2024 |
Reverté, Jaume; Rambla-Alegre, Maria; Sanchez-Henao, Andres; Mandalakis, Manolis; Peristeraki, Panagiota; Molgó, Jordi; Diogène, Jorge; Sureda, Francesc X; Campàs, Mònica Toxicity Equivalency Factors for Tetrodotoxin Analogues Determined with Automated Patch Clamp on Voltage-Gated Sodium Channels in Neuro-2a Cells Journal Article Journal of Agricultural and Food Chemistry, 72 (32), pp. 18192–18200, 2024, ISSN: 0021-8561, 1520-5118. @article{reverte_toxicity_2024, title = {Toxicity Equivalency Factors for Tetrodotoxin Analogues Determined with Automated Patch Clamp on Voltage-Gated Sodium Channels in Neuro-2a Cells}, author = {Jaume Reverté and Maria Rambla-Alegre and Andres Sanchez-Henao and Manolis Mandalakis and Panagiota Peristeraki and Jordi Molgó and Jorge Diogène and Francesc X Sureda and Mònica Campàs}, url = {https://pubs.acs.org/doi/10.1021/acs.jafc.4c04321 https://imbbc.hcmr.gr/wp-content/uploads/2024/09/2024-Reverte-JAFC-42-pre-print.pdf}, doi = {10.1021/acs.jafc.4c04321}, issn = {0021-8561, 1520-5118}, year = {2024}, date = {2024-09-26}, urldate = {2024-09-26}, journal = {Journal of Agricultural and Food Chemistry}, volume = {72}, number = {32}, pages = {18192--18200}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Kondylatos, Gerasimos; Theocharis, Alexandros; Mandalakis, Manolis; Avgoustinaki, Maria; Karagyaurova, Teodora; Koulocheri, Zoi; Vardali, Sofia; Klaoudatos, Dimitris The Devil Firefish Pterois miles (Bennett, 1828): Life History Traits of a Potential Fishing Resource in Rhodes (Eastern Mediterranean) Journal Article Hydrobiology, 3 (1), pp. 31–50, 2024, ISSN: 2673-9917. @article{kondylatos_devil_2024, title = {The Devil Firefish Pterois miles (Bennett, 1828): Life History Traits of a Potential Fishing Resource in Rhodes (Eastern Mediterranean)}, author = {Gerasimos Kondylatos and Alexandros Theocharis and Manolis Mandalakis and Maria Avgoustinaki and Teodora Karagyaurova and Zoi Koulocheri and Sofia Vardali and Dimitris Klaoudatos}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2024/04/2024-Kondylatos-hydrobiology-17.pdf https://www.mdpi.com/2673-9917/3/1/3}, doi = {10.3390/hydrobiology3010003}, issn = {2673-9917}, year = {2024}, date = {2024-04-01}, urldate = {2024-04-02}, journal = {Hydrobiology}, volume = {3}, number = {1}, pages = {31--50}, abstract = {The devil firefish Pterois miles (Bennett 1828) is recognized as one of the 100 worst invasive alien species (IAS) in the Mediterranean Sea with significant socioeconomic and ecological implications. A total of 363 individuals were collected between April 2021 and March 2022 from the Levantine Sea (the Eastern Mediterranean), aiming to assess the current progression of the population. The male to female ratio (1:1.03) did not significantly depart from 1:1, with length–weight relationships exhibiting positive allometric growth. Five age groups were identified, with the third and fourth age groups being the predominant (74% of the population). The highest reproductive intensity was observed during summer followed by autumn. The onset of sexual maturity (L50) for the total population was estimated at 22.44 cm in total length (2.1 years). The asymptotic length was estimated at 45.35 cm for the total population, with males growing larger than females. Longevity was estimated at 14.4 years for the total population. The inflection point was estimated at 4.31 years for the total population. Length with a 50% probability of capture (LC50) was estimated at 23.03 cm, with the respective age (t50) of 2.2 years. The exploitation rate (E = 0.48) indicated that the population is underexploited. The optimum (Fopt) and target (Flim) fishing mortality were higher in comparison with the present fishing mortality (F = 0.41), indicating a potential for commercial exploitation of the species.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The devil firefish Pterois miles (Bennett 1828) is recognized as one of the 100 worst invasive alien species (IAS) in the Mediterranean Sea with significant socioeconomic and ecological implications. A total of 363 individuals were collected between April 2021 and March 2022 from the Levantine Sea (the Eastern Mediterranean), aiming to assess the current progression of the population. The male to female ratio (1:1.03) did not significantly depart from 1:1, with length–weight relationships exhibiting positive allometric growth. Five age groups were identified, with the third and fourth age groups being the predominant (74% of the population). The highest reproductive intensity was observed during summer followed by autumn. The onset of sexual maturity (L50) for the total population was estimated at 22.44 cm in total length (2.1 years). The asymptotic length was estimated at 45.35 cm for the total population, with males growing larger than females. Longevity was estimated at 14.4 years for the total population. The inflection point was estimated at 4.31 years for the total population. Length with a 50% probability of capture (LC50) was estimated at 23.03 cm, with the respective age (t50) of 2.2 years. The exploitation rate (E = 0.48) indicated that the population is underexploited. The optimum (Fopt) and target (Flim) fishing mortality were higher in comparison with the present fishing mortality (F = 0.41), indicating a potential for commercial exploitation of the species. |
Sabotič, Jerica; Bayram, Engin; Ezra, David; Gaudêncio, Susana P; Haznedaroğlu, Berat Z; Janež, Nika; Ktari, Leila; Luganini, Anna; Mandalakis, Manolis; Safarik, Ivo; Simes, Dina; Strode, Evita; Toruńska-Sitarz, Anna; Varamogianni-Mamatsi, Despoina; Varese, Giovanna Cristina; Vasquez, Marlen I A guide to the use of bioassays in exploration of natural resources Journal Article Biotechnology Advances, 71 , pp. 108307, 2024, ISSN: 07349750. @article{sabotic_guide_2024, title = {A guide to the use of bioassays in exploration of natural resources}, author = {Jerica Sabotič and Engin Bayram and David Ezra and Susana P Gaudêncio and Berat Z Haznedaroğlu and Nika Janež and Leila Ktari and Anna Luganini and Manolis Mandalakis and Ivo Safarik and Dina Simes and Evita Strode and Anna Toruńska-Sitarz and Despoina Varamogianni-Mamatsi and Giovanna Cristina Varese and Marlen I Vasquez}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2024/02/2024-Sabotic-Bioassays-Review-9.pdf https://linkinghub.elsevier.com/retrieve/pii/S0734975024000016}, doi = {10.1016/j.biotechadv.2024.108307}, issn = {07349750}, year = {2024}, date = {2024-02-15}, urldate = {2024-02-15}, journal = {Biotechnology Advances}, volume = {71}, pages = {108307}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ventriglia, G; Fakriadis, I; Papadaki, M; Zupa, R; Pousis, C; Mandalakis, M; Corriero, A; Mylonas, C C Effects of different hormonal treatments on spermatogenesis advancement in hatchery-produced greater amberjack Seriola dumerili (Risso 1810) Journal Article 348 , pp. 114447, 2024, ISSN: 00166480. @article{ventriglia_effects_2024, title = {Effects of different hormonal treatments on spermatogenesis advancement in hatchery-produced greater amberjack Seriola dumerili (Risso 1810)}, author = {G Ventriglia and I Fakriadis and M Papadaki and R Zupa and C Pousis and M Mandalakis and A Corriero and C C Mylonas}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2024/02/2024-Ventriglia-GCE-7.pdf https://linkinghub.elsevier.com/retrieve/pii/S0016648024000078}, doi = {10.1016/j.ygcen.2024.114447}, issn = {00166480}, year = {2024}, date = {2024-02-05}, urldate = {2024-02-09}, volume = {348}, pages = {114447}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Lancerotto, Stefano; Fakriadis, Ioannis; Papadaki, Maria; Mandalakis, Manolis; Sigelaki, Irini; Mylonas, Constantinos C Timing of puberty in F1-generation hatchery-produced greater amberjack (Seriola dumerili) Journal Article General and Comparative Endocrinology, 347 , pp. 114414, 2024, ISSN: 00166480. @article{lancerotto_timing_2024, title = {Timing of puberty in F1-generation hatchery-produced greater amberjack (Seriola dumerili)}, author = {Stefano Lancerotto and Ioannis Fakriadis and Maria Papadaki and Manolis Mandalakis and Irini Sigelaki and Constantinos C Mylonas}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2024/01/2024-Lancerotto-GCE-SI-12ISRPF-1.pdf https://linkinghub.elsevier.com/retrieve/pii/S0016648023002198}, doi = {10.1016/j.ygcen.2023.114414}, issn = {00166480}, year = {2024}, date = {2024-01-01}, urldate = {2024-01-10}, journal = {General and Comparative Endocrinology}, volume = {347}, pages = {114414}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2023 |
Varamogianni-Mamatsi, Despoina; Nunes, Maria João; Marques, Vanda; Anastasiou, Thekla I; Kagiampaki, Eirini; Vernadou, Emmanouela; Dailianis, Thanos; Kalogerakis, Nicolas; Branco, Luís C; Rodrigues, Cecília M P; Sobral, Rita G; Gaudêncio, Susana P; Mandalakis, Manolis Marine Drugs, 21 (12), pp. 612, 2023, ISSN: 1660-3397. @article{varamogianni-mamatsi_comparative_2023, title = {Comparative Chemical Profiling and Antimicrobial/Anticancer Evaluation of Extracts from Farmed versus Wild Agelas oroides and Sarcotragus foetidus Sponges}, author = {Despoina Varamogianni-Mamatsi and Maria João Nunes and Vanda Marques and Thekla I Anastasiou and Eirini Kagiampaki and Emmanouela Vernadou and Thanos Dailianis and Nicolas Kalogerakis and Luís C Branco and Cecília M P Rodrigues and Rita G Sobral and Susana P Gaudêncio and Manolis Mandalakis}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/12/2023-Varamogianni-Mamatsi-marinedrugs-62.pdf https://www.mdpi.com/1660-3397/21/12/612}, doi = {10.3390/md21120612}, issn = {1660-3397}, year = {2023}, date = {2023-12-04}, urldate = {2023-12-05}, journal = {Marine Drugs}, volume = {21}, number = {12}, pages = {612}, abstract = {Marine sponges are highly efficient in removing organic pollutants and their cultivation, adjacent to fish farms, is increasingly considered as a strategy for improving seawater quality. Moreover, these invertebrates produce a plethora of bioactive metabolites, which could translate into an extra profit for the aquaculture sector. Here, we investigated the chemical profile and bioactivity of two Mediterranean species (i.e., Agelas oroides and Sarcotragus foetidus) and we assessed whether cultivated sponges differed substantially from their wild counterparts. Metabolomic analysis of crude sponge extracts revealed species-specific chemical patterns, with A. oroides and S. foetidus dominated by alkaloids and lipids, respectively. More importantly, farmed and wild explants of each species demonstrated similar chemical fingerprints, with the majority of the metabolites showing modest differences on a sponge mass-normalized basis. Furthermore, farmed sponge extracts presented similar or slightly lower antibacterial activity against methicillin-resistant Staphylococcus aureus, compared to the extracts resulting from wild sponges. Anticancer assays against human colorectal carcinoma cells (HCT-116) revealed marginally active extracts from both wild and farmed S. foetidus populations. Our study highlights that, besides mitigating organic pollution in fish aquaculture, sponge farming can serve as a valuable resource of biomolecules, with promising potential in pharmaceutical and biomedical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Marine sponges are highly efficient in removing organic pollutants and their cultivation, adjacent to fish farms, is increasingly considered as a strategy for improving seawater quality. Moreover, these invertebrates produce a plethora of bioactive metabolites, which could translate into an extra profit for the aquaculture sector. Here, we investigated the chemical profile and bioactivity of two Mediterranean species (i.e., Agelas oroides and Sarcotragus foetidus) and we assessed whether cultivated sponges differed substantially from their wild counterparts. Metabolomic analysis of crude sponge extracts revealed species-specific chemical patterns, with A. oroides and S. foetidus dominated by alkaloids and lipids, respectively. More importantly, farmed and wild explants of each species demonstrated similar chemical fingerprints, with the majority of the metabolites showing modest differences on a sponge mass-normalized basis. Furthermore, farmed sponge extracts presented similar or slightly lower antibacterial activity against methicillin-resistant Staphylococcus aureus, compared to the extracts resulting from wild sponges. Anticancer assays against human colorectal carcinoma cells (HCT-116) revealed marginally active extracts from both wild and farmed S. foetidus populations. Our study highlights that, besides mitigating organic pollution in fish aquaculture, sponge farming can serve as a valuable resource of biomolecules, with promising potential in pharmaceutical and biomedical applications. |
Anastasiou, Thekla I; Kagiampaki, Eirini; Kondylatos, Gerasimos; Tselepides, Anastasios; Peristeraki, Panagiota; Mandalakis, Manolis Marine Drugs, 21 (10), pp. 520, 2023, ISSN: 1660-3397. @article{anastasiou_assessing_2023, title = {Assessing the Toxicity of Lagocephalus sceleratus Pufferfish from the Southeastern Aegean Sea and the Relationship of Tetrodotoxin with Gonadal Hormones}, author = {Thekla I Anastasiou and Eirini Kagiampaki and Gerasimos Kondylatos and Anastasios Tselepides and Panagiota Peristeraki and Manolis Mandalakis}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/10/2023-Anastasiou-Mardrugs-55.pdf https://www.mdpi.com/1660-3397/21/10/520}, doi = {10.3390/md21100520}, issn = {1660-3397}, year = {2023}, date = {2023-10-11}, urldate = {2023-10-17}, journal = {Marine Drugs}, volume = {21}, number = {10}, pages = {520}, abstract = {Given the dramatic increase in the L. sceleratus population in the southeastern Aegean Sea, there is growing interest in assessing the toxicity of this pufferfish and the factors controlling its tetrodotoxin (TTX) content. In the present study, liver, gonads, muscle and skin of 37 L. sceleratus specimens collected during May and June 2021 from the island of Rhodes, Greece, were subjected to multi-analyte profiling using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to quantitate TTX and evaluate whether this biotoxin interrelates with hormones. TTX and its analogues 4-epiTTX, 11-deoxyTTX, 11-norTTX-6-ol, 4,9-anhydroTTX and 5,11/6,11-dideoxyTTX were detected in all tissue types. Liver and gonads were the most toxic tissues, with the highest TTX concentrations being observed in the ovaries of female specimens. Only 22% of the analyzed muscle samples were non-toxic according to the Japanese toxicity threshold (2.2 μg TTX eq g−1), confirming the high poisoning risk from the inadvertent consumption of this species. Four steroid hormones (i.e., cortisol, testosterone, androstenedione and β-estradiol) and the gonadotropin-releasing hormone (GnRH) were detected in the gonads. Androstenedione dominated in female specimens, while GnRH was more abundant in males. A positive correlation of TTX and its analogues with β-estradiol was observed. However, a model incorporating sex rather than β-estradiol as the independent variable proven to be more efficient in predicting TTX concentration, implying that other sex-related characteristics are more important than specific hormone-regulated processes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Given the dramatic increase in the L. sceleratus population in the southeastern Aegean Sea, there is growing interest in assessing the toxicity of this pufferfish and the factors controlling its tetrodotoxin (TTX) content. In the present study, liver, gonads, muscle and skin of 37 L. sceleratus specimens collected during May and June 2021 from the island of Rhodes, Greece, were subjected to multi-analyte profiling using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to quantitate TTX and evaluate whether this biotoxin interrelates with hormones. TTX and its analogues 4-epiTTX, 11-deoxyTTX, 11-norTTX-6-ol, 4,9-anhydroTTX and 5,11/6,11-dideoxyTTX were detected in all tissue types. Liver and gonads were the most toxic tissues, with the highest TTX concentrations being observed in the ovaries of female specimens. Only 22% of the analyzed muscle samples were non-toxic according to the Japanese toxicity threshold (2.2 μg TTX eq g−1), confirming the high poisoning risk from the inadvertent consumption of this species. Four steroid hormones (i.e., cortisol, testosterone, androstenedione and β-estradiol) and the gonadotropin-releasing hormone (GnRH) were detected in the gonads. Androstenedione dominated in female specimens, while GnRH was more abundant in males. A positive correlation of TTX and its analogues with β-estradiol was observed. However, a model incorporating sex rather than β-estradiol as the independent variable proven to be more efficient in predicting TTX concentration, implying that other sex-related characteristics are more important than specific hormone-regulated processes. |
Alkassar, Mounira; Sanchez-Henao, Andres; Reverté, Jaume; Barreiro, Lourdes; Rambla-Alegre, Maria; Leonardo, Sandra; Mandalakis, Manolis; Peristeraki, Panagiota; Diogène, Jorge; Campàs, Mònica Evaluation of Toxicity Equivalency Factors of Tetrodotoxin Analogues with a Neuro-2a Cell-Based Assay and Application to Puffer Fish from Greece Journal Article Marine Drugs, 21 (8), pp. 432, 2023, ISSN: 1660-3397. @article{alkassar_evaluation_2023, title = {Evaluation of Toxicity Equivalency Factors of Tetrodotoxin Analogues with a Neuro-2a Cell-Based Assay and Application to Puffer Fish from Greece}, author = {Mounira Alkassar and Andres Sanchez-Henao and Jaume Reverté and Lourdes Barreiro and Maria Rambla-Alegre and Sandra Leonardo and Manolis Mandalakis and Panagiota Peristeraki and Jorge Diogène and Mònica Campàs}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/08/2023-Alkassar-marinedrugs-41.pdf https://www.mdpi.com/1660-3397/21/8/432}, doi = {10.3390/md21080432}, issn = {1660-3397}, year = {2023}, date = {2023-08-11}, urldate = {2023-08-17}, journal = {Marine Drugs}, volume = {21}, number = {8}, pages = {432}, abstract = {Tetrodotoxin (TTX) is a potent marine neurotoxin involved in poisoning cases, especially through the consumption of puffer fish. Knowledge of the toxicity equivalency factors (TEFs) of TTX analogues is crucial in monitoring programs to estimate the toxicity of samples analyzed with instrumental analysis methods. In this work, TTX analogues were isolated from the liver of a Lagocephalus sceleratus individual caught on South Crete coasts. A cell-based assay (CBA) for TTXs was optimized and applied to the establishment of the TEFs of 5,11-dideoxyTTX, 11-norTTX-6(S)-ol, 11-deoxyTTX and 5,6,11-trideoxyTTX. Results showed that all TTX analogues were less toxic than the parent TTX, their TEFs being in the range of 0.75–0.011. Then, different tissues of three Lagocephalus sceleratus individuals were analyzed with CBA and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained TEFs were applied to the TTX analogues’ concentrations obtained by LC-MS/MS analysis, providing an indication of the overall toxicity of the sample. Information about the TEFs of TTX analogues is valuable for food safety control, allowing the estimation of the risk of fish products to consumers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Tetrodotoxin (TTX) is a potent marine neurotoxin involved in poisoning cases, especially through the consumption of puffer fish. Knowledge of the toxicity equivalency factors (TEFs) of TTX analogues is crucial in monitoring programs to estimate the toxicity of samples analyzed with instrumental analysis methods. In this work, TTX analogues were isolated from the liver of a Lagocephalus sceleratus individual caught on South Crete coasts. A cell-based assay (CBA) for TTXs was optimized and applied to the establishment of the TEFs of 5,11-dideoxyTTX, 11-norTTX-6(S)-ol, 11-deoxyTTX and 5,6,11-trideoxyTTX. Results showed that all TTX analogues were less toxic than the parent TTX, their TEFs being in the range of 0.75–0.011. Then, different tissues of three Lagocephalus sceleratus individuals were analyzed with CBA and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained TEFs were applied to the TTX analogues’ concentrations obtained by LC-MS/MS analysis, providing an indication of the overall toxicity of the sample. Information about the TEFs of TTX analogues is valuable for food safety control, allowing the estimation of the risk of fish products to consumers. |
Varamogianni-Mamatsi, Despoina; Anastasiou, Thekla I; Vernadou, Emmanouela; Kouvarakis, Nikos; Kagiampaki, Eirini; Kalogerakis, Nicolas; Dailianis, Thanos; Mandalakis, Manolis Uptake of aquaculture-related dissolved organic pollutants by marine sponges: Kinetics and mechanistic insights from a laboratory study Journal Article Science of The Total Environment, 899 , pp. 165601, 2023, ISSN: 00489697. @article{varamogianni-mamatsi_uptake_2023, title = {Uptake of aquaculture-related dissolved organic pollutants by marine sponges: Kinetics and mechanistic insights from a laboratory study}, author = {Despoina Varamogianni-Mamatsi and Thekla I Anastasiou and Emmanouela Vernadou and Nikos Kouvarakis and Eirini Kagiampaki and Nicolas Kalogerakis and Thanos Dailianis and Manolis Mandalakis}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/08/2023-Varamogianni-Mamatsi-STEnv-40-preprint.pdf https://linkinghub.elsevier.com/retrieve/pii/S0048969723042249}, doi = {10.1016/j.scitotenv.2023.165601}, issn = {00489697}, year = {2023}, date = {2023-08-01}, urldate = {2023-08-14}, journal = {Science of The Total Environment}, volume = {899}, pages = {165601}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Gaudêncio, Susana P; Bayram, Engin; Bilela, Lada Lukić; Cueto, Mercedes; Díaz-Marrero, Ana R; Haznedaroglu, Berat Z; Jimenez, Carlos; Mandalakis, Manolis; Pereira, Florbela; Reyes, Fernando; Tasdemir, Deniz Marine Drugs, 21 (5), pp. 308, 2023, ISSN: 1660-3397. @article{gaudencio_advanced_2023, title = {Advanced Methods for Natural Products Discovery: Bioactivity Screening, Dereplication, Metabolomics Profiling, Genomic Sequencing, Databases and Informatic Tools, and Structure Elucidation}, author = {Susana P Gaudêncio and Engin Bayram and Lada Lukić Bilela and Mercedes Cueto and Ana R Díaz-Marrero and Berat Z Haznedaroglu and Carlos Jimenez and Manolis Mandalakis and Florbela Pereira and Fernando Reyes and Deniz Tasdemir}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/06/2023-Gaudencio-Marinedrugs-25.pdf https://www.mdpi.com/1660-3397/21/5/308}, doi = {10.3390/md21050308}, issn = {1660-3397}, year = {2023}, date = {2023-05-30}, urldate = {2023-06-07}, journal = {Marine Drugs}, volume = {21}, number = {5}, pages = {308}, abstract = {Natural Products (NP) are essential for the discovery of novel drugs and products for numerous biotechnological applications. The NP discovery process is expensive and time-consuming, having as major hurdles dereplication (early identification of known compounds) and structure elucidation, particularly the determination of the absolute configuration of metabolites with stereogenic centers. This review comprehensively focuses on recent technological and instrumental advances, highlighting the development of methods that alleviate these obstacles, paving the way for accelerating NP discovery towards biotechnological applications. Herein, we emphasize the most innovative high-throughput tools and methods for advancing bioactivity screening, NP chemical analysis, dereplication, metabolite profiling, metabolomics, genome sequencing and/or genomics approaches, databases, bioinformatics, chemoinformatics, and three-dimensional NP structure elucidation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Natural Products (NP) are essential for the discovery of novel drugs and products for numerous biotechnological applications. The NP discovery process is expensive and time-consuming, having as major hurdles dereplication (early identification of known compounds) and structure elucidation, particularly the determination of the absolute configuration of metabolites with stereogenic centers. This review comprehensively focuses on recent technological and instrumental advances, highlighting the development of methods that alleviate these obstacles, paving the way for accelerating NP discovery towards biotechnological applications. Herein, we emphasize the most innovative high-throughput tools and methods for advancing bioactivity screening, NP chemical analysis, dereplication, metabolite profiling, metabolomics, genome sequencing and/or genomics approaches, databases, bioinformatics, chemoinformatics, and three-dimensional NP structure elucidation. |
2022 |
Varamogianni-Mamatsi, Despoina; Anastasiou, Thekla I; Vernadou, Emmanouela; Papandroulakis, Nikos; Kalogerakis, Nicolas; Dailianis, Thanos; Mandalakis, Manolis A Multi-Species Investigation of Sponges’ Filtering Activity towards Marine Microalgae Journal Article Marine Drugs, 20 (1), pp. 24, 2022, ISSN: 1660-3397. @article{varamogianni-mamatsi_multi-species_2022, title = {A Multi-Species Investigation of Sponges’ Filtering Activity towards Marine Microalgae}, author = {Despoina Varamogianni-Mamatsi and Thekla I Anastasiou and Emmanouela Vernadou and Nikos Papandroulakis and Nicolas Kalogerakis and Thanos Dailianis and Manolis Mandalakis}, url = {https://www.mdpi.com/1660-3397/20/1/24}, doi = {10.3390/md20010024}, issn = {1660-3397}, year = {2022}, date = {2022-01-01}, urldate = {2022-02-28}, journal = {Marine Drugs}, volume = {20}, number = {1}, pages = {24}, abstract = {Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investigated the clearance capacity of four ubiquitous Mediterranean sponges (Agelas oroides, Axinella cannabina, Chondrosia reniformis and Sarcotragus foetidus) against three microalgal substrates with different size/motility characteristics: the nanophytoplankton Nannochloropsis sp. (textasciitilde3.2 μm, nonmotile) and Isochrysis sp. (textasciitilde3.8 μm, motile), as well as the diatom Phaeodactylum tricornutum (textasciitilde21.7 μm, nonmotile). In vitro cleaning experiments were conducted using sponge explants in 1 L of natural seawater and applying different microalgal cell concentrations under light/dark conditions. The investigated sponges exhibited a wide range of retention efficiencies for the different phytoplankton cells, with the lowest average values found for A. cannabina (37%) and the highest for A. oroides (70%). The latter could filter up to 14.1 mL seawater per hour and gram of sponge wet weight, by retaining 100% of Isochrysis at a density of 105 cells mL−1, under darkness. Our results highlight differences in filtering capacity among sponge species and preferences for microalgal substrates with distinct size and motility traits.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investigated the clearance capacity of four ubiquitous Mediterranean sponges (Agelas oroides, Axinella cannabina, Chondrosia reniformis and Sarcotragus foetidus) against three microalgal substrates with different size/motility characteristics: the nanophytoplankton Nannochloropsis sp. (textasciitilde3.2 μm, nonmotile) and Isochrysis sp. (textasciitilde3.8 μm, motile), as well as the diatom Phaeodactylum tricornutum (textasciitilde21.7 μm, nonmotile). In vitro cleaning experiments were conducted using sponge explants in 1 L of natural seawater and applying different microalgal cell concentrations under light/dark conditions. The investigated sponges exhibited a wide range of retention efficiencies for the different phytoplankton cells, with the lowest average values found for A. cannabina (37%) and the highest for A. oroides (70%). The latter could filter up to 14.1 mL seawater per hour and gram of sponge wet weight, by retaining 100% of Isochrysis at a density of 105 cells mL−1, under darkness. Our results highlight differences in filtering capacity among sponge species and preferences for microalgal substrates with distinct size and motility traits. |
Demetriou, Monica; Raitsos, Dionysios E; Kournopoulou, Antonia; Mandalakis, Manolis; Sfenthourakis, Spyros; Psarra, Stella Phytoplankton Phenology in the Coastal Zone of Cyprus, Based on Remote Sensing and In Situ Observations Journal Article Remote Sensing, 14 (1), pp. 12, 2022, ISSN: 2072-4292. @article{demetriou_phytoplankton_2022, title = {Phytoplankton Phenology in the Coastal Zone of Cyprus, Based on Remote Sensing and In Situ Observations}, author = {Monica Demetriou and Dionysios E Raitsos and Antonia Kournopoulou and Manolis Mandalakis and Spyros Sfenthourakis and Stella Psarra}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/03/2022-Demetriou-RemSensing-4.pdf https://www.mdpi.com/2072-4292/14/1/12}, doi = {10.3390/rs14010012}, issn = {2072-4292}, year = {2022}, date = {2022-01-01}, urldate = {2022-03-11}, journal = {Remote Sensing}, volume = {14}, number = {1}, pages = {12}, abstract = {Alterations in phytoplankton biomass, community structure and timing of their growth (phenology), are directly implicated in the carbon cycle and energy transfer to higher trophic levels of the marine food web. Due to the lack of long-term in situ datasets, there is very little information on phytoplankton seasonal succession in Cyprus (eastern Mediterranean Sea). On the other hand, satellite-derived measurements of ocean colour can only provide long-term time series of chlorophyll (an index of phytoplankton biomass) up to the first optical depth (surface waters). The coupling of both means of observations is essential for understanding phytoplankton dynamics and their response to environmental change. Here, we use 23 years of remotely sensed, regionally tuned ocean-colour observations, along with a unique time series of in situ phytoplankton pigment composition data, collected in coastal waters of Cyprus during 2016. The satellite observations show an initiation of phytoplankton growth period in November, a peak in February and termination in April, with an overall mean duration of textasciitilde4 months. An in-depth exploration of in situ total Chl-a concentration and phytoplankton pigments revealed that pico- and nano-plankton cells dominated the phytoplankton community. The growth peak in February was dominated by nanophytoplankton and potentially larger diatoms (pigments of 19’ hexanoyloxyfucoxanthin and fucoxanthin, respectively), in the 0–20 m layer. The highest total Chl-a concentration was recorded at a station off Akrotiri peninsula in the south, where strong coastal upwelling has been reported. Another station in the southern part, located next to a fish farm, showed a higher contribution of picophytoplankton during the most oligotrophic period (summer). Our results highlight the importance of using available in situ data coupled to ocean-colour remote sensing, for monitoring marine ecosystems in areas with limited in situ data availability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Alterations in phytoplankton biomass, community structure and timing of their growth (phenology), are directly implicated in the carbon cycle and energy transfer to higher trophic levels of the marine food web. Due to the lack of long-term in situ datasets, there is very little information on phytoplankton seasonal succession in Cyprus (eastern Mediterranean Sea). On the other hand, satellite-derived measurements of ocean colour can only provide long-term time series of chlorophyll (an index of phytoplankton biomass) up to the first optical depth (surface waters). The coupling of both means of observations is essential for understanding phytoplankton dynamics and their response to environmental change. Here, we use 23 years of remotely sensed, regionally tuned ocean-colour observations, along with a unique time series of in situ phytoplankton pigment composition data, collected in coastal waters of Cyprus during 2016. The satellite observations show an initiation of phytoplankton growth period in November, a peak in February and termination in April, with an overall mean duration of textasciitilde4 months. An in-depth exploration of in situ total Chl-a concentration and phytoplankton pigments revealed that pico- and nano-plankton cells dominated the phytoplankton community. The growth peak in February was dominated by nanophytoplankton and potentially larger diatoms (pigments of 19’ hexanoyloxyfucoxanthin and fucoxanthin, respectively), in the 0–20 m layer. The highest total Chl-a concentration was recorded at a station off Akrotiri peninsula in the south, where strong coastal upwelling has been reported. Another station in the southern part, located next to a fish farm, showed a higher contribution of picophytoplankton during the most oligotrophic period (summer). Our results highlight the importance of using available in situ data coupled to ocean-colour remote sensing, for monitoring marine ecosystems in areas with limited in situ data availability. |
2021 |
Papadaki, Maria; Mandalakis, Manolis; Anastasiou, Thekla I; Pouli, Marina; Asderis, Michalis; Katharios, Pantelis; Papandroulakis, Nikos; Mylonas, Constantinos C Fish Physiology and Biochemistry, 47 (6), pp. 1777–1792, 2021, ISSN: 1573-5168. @article{papadaki_histological_2021b, title = {Histological evaluation of sex differentiation and early sex identification in hatchery-produced greater amberjack (Seriola dumerili) reared in sea cages}, author = {Maria Papadaki and Manolis Mandalakis and Thekla I Anastasiou and Marina Pouli and Michalis Asderis and Pantelis Katharios and Nikos Papandroulakis and Constantinos C Mylonas}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/01/2021-Papadaki-FFB-82-pre-print.pdf https://doi.org/10.1007/s10695-021-01007-7}, doi = {10.1007/s10695-021-01007-7}, issn = {1573-5168}, year = {2021}, date = {2021-12-01}, urldate = {2021-12-04}, journal = {Fish Physiology and Biochemistry}, volume = {47}, number = {6}, pages = {1777--1792}, abstract = {The histological process of gonadal differentiation, together with the endocrine changes of sex steroid hormones and some of their precursors, was studied in hatchery-produced greater amberjack Seriola dumerili from 101 until 408 days post-hatching (dph), with samplings conducted every 50 days. Histological processing showed that sex differentiation began at 101 dph with the formation of the ovarian cavity in females, while the presumptive males did not yet contain any germ cells in their gonad. At 150 dph, we observed the first germ cells in the developing testes. Sex differentiation in almost all sampled individuals was complete at 408 dph. No size dimorphism was observed between the sexes, and the sex ratio was 1:1, suggesting that there was no influence of early rearing in captivity on sex differentiation. Plasma concentrations of adrenosterone (Ad), androstenedione (Δ4), 11-ketotestosterone (11ΚΤ), testosterone (Τ), estradiol (Ε2), progesterone (P4) and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured in males and females with the use of liquid chromatography tandem mass spectrometry (LC–MS/MS) to examine their role in the sex differentiation process. From the seven hormones, the only one that exhibited differences between the sexes was 11-KT and the plasma 11-KT concentration was found to be a useful indication of greater amberjack sex. Variations were observed in the mean values of Ad, Δ4, 11-KT, T, P4 and 17,20βP over time in one or both sexes, indicating their involvement in the sex differentiation process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The histological process of gonadal differentiation, together with the endocrine changes of sex steroid hormones and some of their precursors, was studied in hatchery-produced greater amberjack Seriola dumerili from 101 until 408 days post-hatching (dph), with samplings conducted every 50 days. Histological processing showed that sex differentiation began at 101 dph with the formation of the ovarian cavity in females, while the presumptive males did not yet contain any germ cells in their gonad. At 150 dph, we observed the first germ cells in the developing testes. Sex differentiation in almost all sampled individuals was complete at 408 dph. No size dimorphism was observed between the sexes, and the sex ratio was 1:1, suggesting that there was no influence of early rearing in captivity on sex differentiation. Plasma concentrations of adrenosterone (Ad), androstenedione (Δ4), 11-ketotestosterone (11ΚΤ), testosterone (Τ), estradiol (Ε2), progesterone (P4) and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured in males and females with the use of liquid chromatography tandem mass spectrometry (LC–MS/MS) to examine their role in the sex differentiation process. From the seven hormones, the only one that exhibited differences between the sexes was 11-KT and the plasma 11-KT concentration was found to be a useful indication of greater amberjack sex. Variations were observed in the mean values of Ad, Δ4, 11-KT, T, P4 and 17,20βP over time in one or both sexes, indicating their involvement in the sex differentiation process. |
Christidis, Georgios; Mandalakis, Manolis; Anastasiou, Thekla I; Tserpes, George; Peristeraki, Panagiota; Somarakis, Stylianos Keeping Lagocephalus sceleratus off the Table: Sources of Variation in the Quantity of TTX, TTX Analogues, and Risk of Tetrodotoxication Journal Article Toxins, 13 (12), pp. 896, 2021, ISSN: 2072-6651, (BIODIV). @article{christidis_keeping_2021b, title = {Keeping Lagocephalus sceleratus off the Table: Sources of Variation in the Quantity of TTX, TTX Analogues, and Risk of Tetrodotoxication}, author = {Georgios Christidis and Manolis Mandalakis and Thekla I Anastasiou and George Tserpes and Panagiota Peristeraki and Stylianos Somarakis}, url = {https://www.mdpi.com/2072-6651/13/12/896}, doi = {10.3390/toxins13120896}, issn = {2072-6651}, year = {2021}, date = {2021-12-01}, urldate = {2022-01-17}, journal = {Toxins}, volume = {13}, number = {12}, pages = {896}, abstract = {The invasion of the tetrodotoxin (TTX)-bearing silver-cheeked toadfish and potential poisoning due to its consumption (tetrodotoxication) threatens public safety in the Mediterranean Sea. In this study, TTX and TTX analogues of Lagocephalus sceleratus (Gmelin, 1789) were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in fish collected off the island of Crete (Southern Mediterranean). We tested the synergistic effect of a suite of factors potentially affecting toxins’ levels and tetrodotoxication risk using general and generalized linear models, respectively. The type of tissue, geographic origin (Cretan Sea, Libyan Sea), sex, and fish maturity stage were significant predictors of toxin concentrations. Mean TTX was higher in gonads and lower in muscles, higher in the Libyan Sea and in female fish, and lower in juvenile (virgin) fish. The concentration of TTX was also significantly and positively correlated with the concentration of several TTX analogues (4-epiTTX, 4,9-anhydroTTX, 11-deoxyTTX, 5,11/6,11-dideoxyTTX, 5,6,11-trideoxyTTX, 11-norTTX-6-ol). The analysis showed that fish originating from the Libyan Sea had significantly higher probability to cause tetrodotoxication in case of consumption. The variability explained by the models developed in this study was relatively low, indicating that toxin levels are hard to predict and the consumption of L. sceleratus should therefore be avoided.}, note = {BIODIV}, keywords = {}, pubstate = {published}, tppubtype = {article} } The invasion of the tetrodotoxin (TTX)-bearing silver-cheeked toadfish and potential poisoning due to its consumption (tetrodotoxication) threatens public safety in the Mediterranean Sea. In this study, TTX and TTX analogues of Lagocephalus sceleratus (Gmelin, 1789) were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in fish collected off the island of Crete (Southern Mediterranean). We tested the synergistic effect of a suite of factors potentially affecting toxins’ levels and tetrodotoxication risk using general and generalized linear models, respectively. The type of tissue, geographic origin (Cretan Sea, Libyan Sea), sex, and fish maturity stage were significant predictors of toxin concentrations. Mean TTX was higher in gonads and lower in muscles, higher in the Libyan Sea and in female fish, and lower in juvenile (virgin) fish. The concentration of TTX was also significantly and positively correlated with the concentration of several TTX analogues (4-epiTTX, 4,9-anhydroTTX, 11-deoxyTTX, 5,11/6,11-dideoxyTTX, 5,6,11-trideoxyTTX, 11-norTTX-6-ol). The analysis showed that fish originating from the Libyan Sea had significantly higher probability to cause tetrodotoxication in case of consumption. The variability explained by the models developed in this study was relatively low, indicating that toxin levels are hard to predict and the consumption of L. sceleratus should therefore be avoided. |
Medvecky, Matej; Mandalakis, Manolis PepMANDIS: A Peptide Selection Tool for Designing Function-Based Targeted Proteomic Assays in Complex Microbial Systems Journal Article Frontiers in Chemistry, 9 , pp. 722087, 2021, ISSN: 2296-2646. @article{medvecky_pepmandis_2021, title = {PepMANDIS: A Peptide Selection Tool for Designing Function-Based Targeted Proteomic Assays in Complex Microbial Systems}, author = {Matej Medvecky and Manolis Mandalakis}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2021/08/2021-Mandalakis-FiChem-62.pdf https://www.frontiersin.org/articles/10.3389/fchem.2021.722087/full}, doi = {10.3389/fchem.2021.722087}, issn = {2296-2646}, year = {2021}, date = {2021-08-01}, urldate = {2021-08-23}, journal = {Frontiers in Chemistry}, volume = {9}, pages = {722087}, abstract = {The majority of studies focusing on microbial functioning in various environments are based on DNA or RNA sequencing techniques that have inherent limitations and usually provide a distorted picture about the functional status of the studied system. Untargeted proteomics is better suited for that purpose, but it suffers from low efficiency when applied in complex consortia. In practice, the scanning capabilities of the currently employed LC-MS/MS systems provide limited coverage of key-acting proteins, hardly allowing a semiquantitative assessment of the most abundant ones from most prevalent species. When particular biological processes of high importance are under investigation, the analysis of specific proteins using targeted proteomics is a more appropriate strategy as it offers superior sensitivity and comes with the added benefits of increased throughput, dynamic range and selectivity. However, the development of targeted assays requires a priori knowledge regarding the optimal peptides to be screened for each protein of interest. In complex, multi-species systems, a specific biochemical process may be driven by a large number of homologous proteins having considerable differences in their amino acid sequence, complicating LC-MS/MS detection. To overcome the complexity of such systems, we have developed an automated pipeline that interrogates UniProt database or user-created protein datasets (e.g. from metagenomic studies) to gather homolog proteins with a defined functional role and extract respective peptide sequences, while it computes several protein/peptide properties and relevant statistics to deduce a small list of the most representative, process-specific and LC-MS/MS-amenable peptides for the microbial enzymatic activity of interest.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The majority of studies focusing on microbial functioning in various environments are based on DNA or RNA sequencing techniques that have inherent limitations and usually provide a distorted picture about the functional status of the studied system. Untargeted proteomics is better suited for that purpose, but it suffers from low efficiency when applied in complex consortia. In practice, the scanning capabilities of the currently employed LC-MS/MS systems provide limited coverage of key-acting proteins, hardly allowing a semiquantitative assessment of the most abundant ones from most prevalent species. When particular biological processes of high importance are under investigation, the analysis of specific proteins using targeted proteomics is a more appropriate strategy as it offers superior sensitivity and comes with the added benefits of increased throughput, dynamic range and selectivity. However, the development of targeted assays requires a priori knowledge regarding the optimal peptides to be screened for each protein of interest. In complex, multi-species systems, a specific biochemical process may be driven by a large number of homologous proteins having considerable differences in their amino acid sequence, complicating LC-MS/MS detection. To overcome the complexity of such systems, we have developed an automated pipeline that interrogates UniProt database or user-created protein datasets (e.g. from metagenomic studies) to gather homolog proteins with a defined functional role and extract respective peptide sequences, while it computes several protein/peptide properties and relevant statistics to deduce a small list of the most representative, process-specific and LC-MS/MS-amenable peptides for the microbial enzymatic activity of interest. |
Rotter, Ana; Barbier, Michéle; Bertoni, Francesco; Bones, Atle M; Cancela, Leonor M; Carlsson, Jens; Carvalho, Maria F; Cegłowska, Marta; Chirivella-Martorell, Jerónimo; Dalay, Meltem Conk; Cueto, Mercedes; Dailianis, Thanos; Deniz, Irem; Díaz-Marrero, Ana R; Drakulovic, Dragana; Dubnika, Arita; Edwards, Christine; Einarsson, Hjörleifur; Erdoǧan, Ayşegül; Eroldoǧan, Orhan Tufan; Ezra, David; Fazi, Stefano; FitzGerald, Richard J; Gargan, Laura M; Gaudêncio, Susana P; Udovič, Marija Gligora; DeNardis, Nadica Ivošević; Jónsdóttir, Rósa; Kataržytė, Marija; Klun, Katja; Kotta, Jonne; Ktari, Leila; Ljubešić, Zrinka; Bilela, Lada Lukić; Mandalakis, Manolis; Massa-Gallucci, Alexia; Matijošytė, Inga; Mazur-Marzec, Hanna; Mehiri, Mohamed; Nielsen, Søren Laurentius; Novoveská, Lucie; Overlingė, Donata; Perale, Giuseppe; Ramasamy, Praveen; Rebours, Céline; Reinsch, Thorsten; Reyes, Fernando; Rinkevich, Baruch; Robbens, Johan; Röttinger, Eric; Rudovica, Vita; Sabotič, Jerica; Safarik, Ivo; Talve, Siret; Tasdemir, Deniz; Schneider, Xenia Theodotou; Thomas, Olivier P; Toruńska-Sitarz, Anna; Varese, Giovanna Cristina; Vasquez, Marlen I The Essentials of Marine Biotechnology Journal Article Front. Mar. Sci., 8 , pp. 629629, 2021, ISSN: 2296-7745. @article{rotter_essentials_2021, title = {The Essentials of Marine Biotechnology}, author = {Ana Rotter and Michéle Barbier and Francesco Bertoni and Atle M Bones and Leonor M Cancela and Jens Carlsson and Maria F Carvalho and Marta Cegłowska and Jerónimo Chirivella-Martorell and Meltem Conk Dalay and Mercedes Cueto and Thanos Dailianis and Irem Deniz and Ana R Díaz-Marrero and Dragana Drakulovic and Arita Dubnika and Christine Edwards and Hjörleifur Einarsson and Ayşegül Erdoǧan and Orhan Tufan Eroldoǧan and David Ezra and Stefano Fazi and Richard J FitzGerald and Laura M Gargan and Susana P Gaudêncio and Marija Gligora Udovič and Nadica Ivošević DeNardis and Rósa Jónsdóttir and Marija Kataržytė and Katja Klun and Jonne Kotta and Leila Ktari and Zrinka Ljubešić and Lada Lukić Bilela and Manolis Mandalakis and Alexia Massa-Gallucci and Inga Matijošytė and Hanna Mazur-Marzec and Mohamed Mehiri and Søren Laurentius Nielsen and Lucie Novoveská and Donata Overlingė and Giuseppe Perale and Praveen Ramasamy and Céline Rebours and Thorsten Reinsch and Fernando Reyes and Baruch Rinkevich and Johan Robbens and Eric Röttinger and Vita Rudovica and Jerica Sabotič and Ivo Safarik and Siret Talve and Deniz Tasdemir and Xenia Theodotou Schneider and Olivier P Thomas and Anna Toruńska-Sitarz and Giovanna Cristina Varese and Marlen I Vasquez}, url = {https://www.frontiersin.org/articles/10.3389/fmars.2021.629629/full https://imbbc.hcmr.gr/wp-content/uploads/2021/03/2021-Rotter-Frontiers-MS-26.pdf }, doi = {10.3389/fmars.2021.629629}, issn = {2296-7745}, year = {2021}, date = {2021-03-01}, urldate = {2021-03-17}, journal = {Front. Mar. Sci.}, volume = {8}, pages = {629629}, abstract = {Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better health and well-being, new biomedicines, natural cosmeceuticals, environmental conservation, and sustainable energy sources. These societal needs stimulated the interest of researchers on the diverse and underexplored marine environments as promising and sustainable sources of biomolecules and biomass, and they are addressed by the emerging field of marine (blue) biotechnology. Blue biotechnology provides opportunities for a wide range of initiatives of commercial interest for the pharmaceutical, biomedical, cosmetic, nutraceutical, food, feed, agricultural, and related industries. This article synthesizes the essence, opportunities, responsibilities, and challenges encountered in marine biotechnology and outlines the attainment and valorization of directly derived or bio-inspired products from marine organisms. First, the concept of bioeconomy is introduced. Then, the diversity of marine bioresources including an overview of the most prominent marine organisms and their potential for biotechnological uses are described. This is followed by introducing methodologies for exploration of these resources and the main use case scenarios in energy, food and feed, agronomy, bioremediation and climate change, cosmeceuticals, bio-inspired materials, healthcare, and well-being sectors. The key aspects in the fields of legislation and funding are provided, with the emphasis on the importance of communication and stakeholder engagement at all levels of biotechnology development. Finally, vital overarching concepts, such as the quadruple helix and Responsible Research and Innovation principle are highlighted as important to follow within the marine biotechnology field. The authors of this review are collaborating under the European Commission-funded Cooperation in Science and Technology (COST) Action Ocean4Biotech – European transdisciplinary networking platform for marine biotechnology and focus the study on the European state of affairs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better health and well-being, new biomedicines, natural cosmeceuticals, environmental conservation, and sustainable energy sources. These societal needs stimulated the interest of researchers on the diverse and underexplored marine environments as promising and sustainable sources of biomolecules and biomass, and they are addressed by the emerging field of marine (blue) biotechnology. Blue biotechnology provides opportunities for a wide range of initiatives of commercial interest for the pharmaceutical, biomedical, cosmetic, nutraceutical, food, feed, agricultural, and related industries. This article synthesizes the essence, opportunities, responsibilities, and challenges encountered in marine biotechnology and outlines the attainment and valorization of directly derived or bio-inspired products from marine organisms. First, the concept of bioeconomy is introduced. Then, the diversity of marine bioresources including an overview of the most prominent marine organisms and their potential for biotechnological uses are described. This is followed by introducing methodologies for exploration of these resources and the main use case scenarios in energy, food and feed, agronomy, bioremediation and climate change, cosmeceuticals, bio-inspired materials, healthcare, and well-being sectors. The key aspects in the fields of legislation and funding are provided, with the emphasis on the importance of communication and stakeholder engagement at all levels of biotechnology development. Finally, vital overarching concepts, such as the quadruple helix and Responsible Research and Innovation principle are highlighted as important to follow within the marine biotechnology field. The authors of this review are collaborating under the European Commission-funded Cooperation in Science and Technology (COST) Action Ocean4Biotech – European transdisciplinary networking platform for marine biotechnology and focus the study on the European state of affairs. |
Bravakos, Panos; Mandalakis, Manolis; Nomikou, Paraskevi; Anastasiou, Thekla I; Kristoffersen, Jon Bent; Stavroulaki, Melanthia; Kilias, Stephanos; Kotoulas, Georgios; Magoulas, Antonios; Polymenakou, Paraskevi N Genomic adaptation of Pseudomonas strains to acidity and antibiotics in hydrothermal vents at Kolumbo submarine volcano, Greece Journal Article Sci Rep, 11 (1), pp. 1336, 2021, ISSN: 2045-2322. @article{bravakos_genomic_2021, title = {Genomic adaptation of Pseudomonas strains to acidity and antibiotics in hydrothermal vents at Kolumbo submarine volcano, Greece}, author = {Panos Bravakos and Manolis Mandalakis and Paraskevi Nomikou and Thekla I Anastasiou and Jon Bent Kristoffersen and Melanthia Stavroulaki and Stephanos Kilias and Georgios Kotoulas and Antonios Magoulas and Paraskevi N Polymenakou}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2021/02/2021-Bravakos-SciReport-4.pdf http://www.nature.com/articles/s41598-020-79359-y}, doi = {10.1038/s41598-020-79359-y}, issn = {2045-2322}, year = {2021}, date = {2021-01-01}, urldate = {2021-02-02}, journal = {Sci Rep}, volume = {11}, number = {1}, pages = {1336}, abstract = {Abstract Although the rise of antibiotic and multidrug resistant bacteria is one of the biggest current threats to human health, our understanding of the mechanisms involved in antibiotic resistance selection remains scarce. We performed whole genome sequencing of 21 Pseudomonas strains, previously isolated from an active submarine volcano of Greece, the Kolumbo volcano. Our goal was to identify the genetic basis of the enhanced co-tolerance to antibiotics and acidity of these Pseudomonas strains. Pangenome analysis identified 10,908 Gene Clusters (GCs). It revealed that the numbers of phage-related GCs and sigma factors, which both provide the mechanisms of adaptation to environmental stressors, were much higher in the high tolerant Pseudomonas strains compared to the rest ones. All identified GCs of these strains were associated with antimicrobial and multidrug resistance. The present study provides strong evidence that the CO 2 -rich seawater of the volcano associated with low pH might be a reservoir of microorganisms carrying multidrug efflux-mediated systems and pumps. We, therefore, suggest further studies of other extreme environments (or ecosystems) and their associated physicochemical parameters (or factors) in the rise of antibiotic resistance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Although the rise of antibiotic and multidrug resistant bacteria is one of the biggest current threats to human health, our understanding of the mechanisms involved in antibiotic resistance selection remains scarce. We performed whole genome sequencing of 21 Pseudomonas strains, previously isolated from an active submarine volcano of Greece, the Kolumbo volcano. Our goal was to identify the genetic basis of the enhanced co-tolerance to antibiotics and acidity of these Pseudomonas strains. Pangenome analysis identified 10,908 Gene Clusters (GCs). It revealed that the numbers of phage-related GCs and sigma factors, which both provide the mechanisms of adaptation to environmental stressors, were much higher in the high tolerant Pseudomonas strains compared to the rest ones. All identified GCs of these strains were associated with antimicrobial and multidrug resistance. The present study provides strong evidence that the CO 2 -rich seawater of the volcano associated with low pH might be a reservoir of microorganisms carrying multidrug efflux-mediated systems and pumps. We, therefore, suggest further studies of other extreme environments (or ecosystems) and their associated physicochemical parameters (or factors) in the rise of antibiotic resistance. |
Polymenakou, Paraskevi N; Nomikou, Paraskevi; Zafeiropoulos, Haris; Mandalakis, Manolis; Anastasiou, Thekla I; Kilias, Stephanos; Kyrpides, Nikos C; Kotoulas, Georgios; Magoulas, Antoniοs The Santorini Volcanic Complex as a Valuable Source of Enzymes for Bioenergy Journal Article Energies, 14 (5), pp. 1414, 2021, ISSN: 1996-1073. @article{polymenakou_santorini_2021, title = {The Santorini Volcanic Complex as a Valuable Source of Enzymes for Bioenergy}, author = {Paraskevi N Polymenakou and Paraskevi Nomikou and Haris Zafeiropoulos and Manolis Mandalakis and Thekla I Anastasiou and Stephanos Kilias and Nikos C Kyrpides and Georgios Kotoulas and Antoniοs Magoulas}, url = {https://www.mdpi.com/1996-1073/14/5/1414 https://imbbc.hcmr.gr/wp-content/uploads/2021/03/2021-Polymenakou-ENERGIES-24.pdf}, doi = {10.3390/en14051414}, issn = {1996-1073}, year = {2021}, date = {2021-01-01}, urldate = {2021-03-17}, journal = {Energies}, volume = {14}, number = {5}, pages = {1414}, abstract = {Marine microbial communities are an untapped reservoir of genetic and metabolic diversity and a valuable source for the discovery of new natural products of biotechnological interest. The newly discovered hydrothermal vent field of Santorini volcanic complex located in the Aegean Sea is gaining increasing interest for potential biotechnological exploitation. The conditions in these environments, i.e., high temperatures, low pH values and high concentration of heavy metals, often resemble harsh industrial settings. Thus, these environments may serve as pools of enzymes of enhanced catalytic properties that may provide benefits to biotechnology. Here, we screened 11 metagenomic libraries previously constructed from microbial mat samples covering the seafloor and the polymetallic chimneys of Kolumbo volcano as well as mat samples from Santorini caldera, to mine, in silico, genes associated with bioenergy applications. We particularly focused on genes encoding biomass hydrolysis enzymes such as cellulases, hemicellulases and lignin-degrading enzymes. A total of 10,417 genes were found for three specific groups of enzymes—i.e., the endoglucanases, the three different beta-glucosidases BGL, bglX and bglB, and the alpha-galactosidases melA, and rafA. Overall, we concluded that the Santorini–Kolumbo volcanic ecosystems constitute a significant resource of novel genes with potential applications in bioenergy that deserve further investigation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Marine microbial communities are an untapped reservoir of genetic and metabolic diversity and a valuable source for the discovery of new natural products of biotechnological interest. The newly discovered hydrothermal vent field of Santorini volcanic complex located in the Aegean Sea is gaining increasing interest for potential biotechnological exploitation. The conditions in these environments, i.e., high temperatures, low pH values and high concentration of heavy metals, often resemble harsh industrial settings. Thus, these environments may serve as pools of enzymes of enhanced catalytic properties that may provide benefits to biotechnology. Here, we screened 11 metagenomic libraries previously constructed from microbial mat samples covering the seafloor and the polymetallic chimneys of Kolumbo volcano as well as mat samples from Santorini caldera, to mine, in silico, genes associated with bioenergy applications. We particularly focused on genes encoding biomass hydrolysis enzymes such as cellulases, hemicellulases and lignin-degrading enzymes. A total of 10,417 genes were found for three specific groups of enzymes—i.e., the endoglucanases, the three different beta-glucosidases BGL, bglX and bglB, and the alpha-galactosidases melA, and rafA. Overall, we concluded that the Santorini–Kolumbo volcanic ecosystems constitute a significant resource of novel genes with potential applications in bioenergy that deserve further investigation. |
Mandalakis, Manolis; Anastasiou, Thekla I; Martou, Natalia; Keisaris, Sofoklis; Greveniotis, Vasileios; Katharios, Pantelis; Lazari, Diamanto; Krigas, Nikos; Antonopoulou, Efthimia Molecules, 26 (9), pp. 2731, 2021. @article{mandalakis_antibacterial_2021, title = {Antibacterial Effects of Essential Oils of Seven Medicinal-Aromatic Plants Against the Fish Pathogen Aeromonas veronii bv. sobria: To Blend or Not to Blend?}, author = {Manolis Mandalakis and Thekla I Anastasiou and Natalia Martou and Sofoklis Keisaris and Vasileios Greveniotis and Pantelis Katharios and Diamanto Lazari and Nikos Krigas and Efthimia Antonopoulou}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2021/05/2021-Mandalakis-molecules-37.pdf https://www.mdpi.com/1420-3049/26/9/2731}, doi = {10.3390/molecules26092731}, year = {2021}, date = {2021-01-01}, urldate = {2021-05-10}, journal = {Molecules}, volume = {26}, number = {9}, pages = {2731}, abstract = {Despite progress achieved, there is limited available information about the antibacterial activity of constituents of essential oils (EOs) from different medicinal-aromatic plants (MAPs) against fish pathogens and the complex interactions of blended EOs thereof. The present study aimed to investigate possible synergistic antimicrobial effects of EOs from seven Greek MAPs with strong potential against Aeromonas veronii bv. sobria, a fish pathogen associated with aquaculture disease outbreaks. The main objective was to evaluate whether blending of these EOs can lead to increased antimicrobial activity against the specific microorganism. A total of 127 combinations of EOs were prepared and their effect on A. veronii bv. sobria growth was tested in vitro. We examined both the inhibitory and bactericidal activities of the individual EOs and compared them to those of the blended EOs. The vast majority of the investigated combinations exhibited significant synergistic and additive effects, while antagonistic effects were evident only in a few cases, such as the mixtures containing EOs from rosemary, lemon balm and pennyroyal. The combination of EOs from Greek oregano and wild carrot, as well as the combinations of those two with Spanish oregano or savoury were the most promising ones. Overall, Greek oregano, savoury and Spanish oregano EOs were the most effective ones when applied either in pure form or blended with other EOs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Despite progress achieved, there is limited available information about the antibacterial activity of constituents of essential oils (EOs) from different medicinal-aromatic plants (MAPs) against fish pathogens and the complex interactions of blended EOs thereof. The present study aimed to investigate possible synergistic antimicrobial effects of EOs from seven Greek MAPs with strong potential against Aeromonas veronii bv. sobria, a fish pathogen associated with aquaculture disease outbreaks. The main objective was to evaluate whether blending of these EOs can lead to increased antimicrobial activity against the specific microorganism. A total of 127 combinations of EOs were prepared and their effect on A. veronii bv. sobria growth was tested in vitro. We examined both the inhibitory and bactericidal activities of the individual EOs and compared them to those of the blended EOs. The vast majority of the investigated combinations exhibited significant synergistic and additive effects, while antagonistic effects were evident only in a few cases, such as the mixtures containing EOs from rosemary, lemon balm and pennyroyal. The combination of EOs from Greek oregano and wild carrot, as well as the combinations of those two with Spanish oregano or savoury were the most promising ones. Overall, Greek oregano, savoury and Spanish oregano EOs were the most effective ones when applied either in pure form or blended with other EOs. |
Papadaki, Maria; Mandalakis, Manolis; Anastasiou, Thekla I; Pouli, Marina; Asderis, Michalis; Katharios, Pantelis; Papandroulakis, Nikos; Mylonas, Constantinos C Fish Physiology and Biochemistry, 47 (6), pp. 1777–1792, 2021, ISSN: 1573-5168. @article{papadaki_histological_2021, title = {Histological evaluation of sex differentiation and early sex identification in hatchery-produced greater amberjack (Seriola dumerili) reared in sea cages}, author = {Maria Papadaki and Manolis Mandalakis and Thekla I Anastasiou and Marina Pouli and Michalis Asderis and Pantelis Katharios and Nikos Papandroulakis and Constantinos C Mylonas}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2021/12/2021-Papadaki-FFB-69-pre-print-1.pdf https://doi.org/10.1007/s10695-021-01007-7}, doi = {10.1007/s10695-021-01007-7}, issn = {1573-5168}, year = {2021}, date = {2021-01-01}, urldate = {2021-12-04}, journal = {Fish Physiology and Biochemistry}, volume = {47}, number = {6}, pages = {1777--1792}, abstract = {The histological process of gonadal differentiation, together with the endocrine changes of sex steroid hormones and some of their precursors, was studied in hatchery-produced greater amberjack Seriola dumerili from 101 until 408 days post-hatching (dph), with samplings conducted every 50 days. Histological processing showed that sex differentiation began at 101 dph with the formation of the ovarian cavity in females, while the presumptive males did not yet contain any germ cells in their gonad. At 150 dph, we observed the first germ cells in the developing testes. Sex differentiation in almost all sampled individuals was complete at 408 dph. No size dimorphism was observed between the sexes, and the sex ratio was 1:1, suggesting that there was no influence of early rearing in captivity on sex differentiation. Plasma concentrations of adrenosterone (Ad), androstenedione (Δ4), 11-ketotestosterone (11ΚΤ), testosterone (Τ), estradiol (Ε2), progesterone (P4) and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured in males and females with the use of liquid chromatography tandem mass spectrometry (LC–MS/MS) to examine their role in the sex differentiation process. From the seven hormones, the only one that exhibited differences between the sexes was 11-KT and the plasma 11-KT concentration was found to be a useful indication of greater amberjack sex. Variations were observed in the mean values of Ad, Δ4, 11-KT, T, P4 and 17,20βP over time in one or both sexes, indicating their involvement in the sex differentiation process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The histological process of gonadal differentiation, together with the endocrine changes of sex steroid hormones and some of their precursors, was studied in hatchery-produced greater amberjack Seriola dumerili from 101 until 408 days post-hatching (dph), with samplings conducted every 50 days. Histological processing showed that sex differentiation began at 101 dph with the formation of the ovarian cavity in females, while the presumptive males did not yet contain any germ cells in their gonad. At 150 dph, we observed the first germ cells in the developing testes. Sex differentiation in almost all sampled individuals was complete at 408 dph. No size dimorphism was observed between the sexes, and the sex ratio was 1:1, suggesting that there was no influence of early rearing in captivity on sex differentiation. Plasma concentrations of adrenosterone (Ad), androstenedione (Δ4), 11-ketotestosterone (11ΚΤ), testosterone (Τ), estradiol (Ε2), progesterone (P4) and 17,20β-dihydroxy-4-pregnen-3-one (17,20βP) were measured in males and females with the use of liquid chromatography tandem mass spectrometry (LC–MS/MS) to examine their role in the sex differentiation process. From the seven hormones, the only one that exhibited differences between the sexes was 11-KT and the plasma 11-KT concentration was found to be a useful indication of greater amberjack sex. Variations were observed in the mean values of Ad, Δ4, 11-KT, T, P4 and 17,20βP over time in one or both sexes, indicating their involvement in the sex differentiation process. |
Christidis, Georgios; Mandalakis, Manolis; Anastasiou, Thekla I; Tserpes, George; Peristeraki, Panagiota; Somarakis, Stylianos Keeping Lagocephalus sceleratus off the Table: Sources of Variation in the Quantity of TTX, TTX Analogues, and Risk of Tetrodotoxication Journal Article Toxins, 13 (12), pp. 896, 2021, ISSN: 2072-6651. @article{christidis_keeping_2021, title = {Keeping Lagocephalus sceleratus off the Table: Sources of Variation in the Quantity of TTX, TTX Analogues, and Risk of Tetrodotoxication}, author = {Georgios Christidis and Manolis Mandalakis and Thekla I Anastasiou and George Tserpes and Panagiota Peristeraki and Stylianos Somarakis}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/01/2021-Christidis-Toxins-87.pdf https://www.mdpi.com/2072-6651/13/12/896}, doi = {10.3390/toxins13120896}, issn = {2072-6651}, year = {2021}, date = {2021-01-01}, urldate = {2022-01-12}, journal = {Toxins}, volume = {13}, number = {12}, pages = {896}, abstract = {The invasion of the tetrodotoxin (TTX)-bearing silver-cheeked toadfish and potential poisoning due to its consumption (tetrodotoxication) threatens public safety in the Mediterranean Sea. In this study, TTX and TTX analogues of Lagocephalus sceleratus (Gmelin, 1789) were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in fish collected off the island of Crete (Southern Mediterranean). We tested the synergistic effect of a suite of factors potentially affecting toxins’ levels and tetrodotoxication risk using general and generalized linear models, respectively. The type of tissue, geographic origin (Cretan Sea, Libyan Sea), sex, and fish maturity stage were significant predictors of toxin concentrations. Mean TTX was higher in gonads and lower in muscles, higher in the Libyan Sea and in female fish, and lower in juvenile (virgin) fish. The concentration of TTX was also significantly and positively correlated with the concentration of several TTX analogues (4-epiTTX, 4,9-anhydroTTX, 11-deoxyTTX, 5,11/6,11-dideoxyTTX, 5,6,11-trideoxyTTX, 11-norTTX-6-ol). The analysis showed that fish originating from the Libyan Sea had significantly higher probability to cause tetrodotoxication in case of consumption. The variability explained by the models developed in this study was relatively low, indicating that toxin levels are hard to predict and the consumption of L. sceleratus should therefore be avoided.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The invasion of the tetrodotoxin (TTX)-bearing silver-cheeked toadfish and potential poisoning due to its consumption (tetrodotoxication) threatens public safety in the Mediterranean Sea. In this study, TTX and TTX analogues of Lagocephalus sceleratus (Gmelin, 1789) were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in fish collected off the island of Crete (Southern Mediterranean). We tested the synergistic effect of a suite of factors potentially affecting toxins’ levels and tetrodotoxication risk using general and generalized linear models, respectively. The type of tissue, geographic origin (Cretan Sea, Libyan Sea), sex, and fish maturity stage were significant predictors of toxin concentrations. Mean TTX was higher in gonads and lower in muscles, higher in the Libyan Sea and in female fish, and lower in juvenile (virgin) fish. The concentration of TTX was also significantly and positively correlated with the concentration of several TTX analogues (4-epiTTX, 4,9-anhydroTTX, 11-deoxyTTX, 5,11/6,11-dideoxyTTX, 5,6,11-trideoxyTTX, 11-norTTX-6-ol). The analysis showed that fish originating from the Libyan Sea had significantly higher probability to cause tetrodotoxication in case of consumption. The variability explained by the models developed in this study was relatively low, indicating that toxin levels are hard to predict and the consumption of L. sceleratus should therefore be avoided. |
Demetriou, Monica; Raitsos, Dionysios E; Kournopoulou, Antonia; Mandalakis, Manolis; Sfenthourakis, Spyros; Psarra, Stella Phytoplankton Phenology in the Coastal Zone of Cyprus, Based on Remote Sensing and In Situ Observations Journal Article Remote Sensing, 14 (1), pp. 12, 2021, ISSN: 2072-4292. @article{demetriou_phytoplankton_2021, title = {Phytoplankton Phenology in the Coastal Zone of Cyprus, Based on Remote Sensing and In Situ Observations}, author = {Monica Demetriou and Dionysios E Raitsos and Antonia Kournopoulou and Manolis Mandalakis and Spyros Sfenthourakis and Stella Psarra}, url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/01/2022-Demetriou-RemSensing-4.pdf https://www.mdpi.com/2072-4292/14/1/12}, doi = {10.3390/rs14010012}, issn = {2072-4292}, year = {2021}, date = {2021-01-01}, urldate = {2022-01-12}, journal = {Remote Sensing}, volume = {14}, number = {1}, pages = {12}, abstract = {Alterations in phytoplankton biomass, community structure and timing of their growth (phenology), are directly implicated in the carbon cycle and energy transfer to higher trophic levels of the marine food web. Due to the lack of long-term in situ datasets, there is very little information on phytoplankton seasonal succession in Cyprus (eastern Mediterranean Sea). On the other hand, satellite-derived measurements of ocean colour can only provide long-term time series of chlorophyll (an index of phytoplankton biomass) up to the first optical depth (surface waters). The coupling of both means of observations is essential for understanding phytoplankton dynamics and their response to environmental change. Here, we use 23 years of remotely sensed, regionally tuned ocean-colour observations, along with a unique time series of in situ phytoplankton pigment composition data, collected in coastal waters of Cyprus during 2016. The satellite observations show an initiation of phytoplankton growth period in November, a peak in February and termination in April, with an overall mean duration of textasciitilde4 months. An in-depth exploration of in situ total Chl-a concentration and phytoplankton pigments revealed that pico- and nano-plankton cells dominated the phytoplankton community. The growth peak in February was dominated by nanophytoplankton and potentially larger diatoms (pigments of 19’ hexanoyloxyfucoxanthin and fucoxanthin, respectively), in the 0–20 m layer. The highest total Chl-a concentration was recorded at a station off Akrotiri peninsula in the south, where strong coastal upwelling has been reported. Another station in the southern part, located next to a fish farm, showed a higher contribution of picophytoplankton during the most oligotrophic period (summer). Our results highlight the importance of using available in situ data coupled to ocean-colour remote sensing, for monitoring marine ecosystems in areas with limited in situ data availability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Alterations in phytoplankton biomass, community structure and timing of their growth (phenology), are directly implicated in the carbon cycle and energy transfer to higher trophic levels of the marine food web. Due to the lack of long-term in situ datasets, there is very little information on phytoplankton seasonal succession in Cyprus (eastern Mediterranean Sea). On the other hand, satellite-derived measurements of ocean colour can only provide long-term time series of chlorophyll (an index of phytoplankton biomass) up to the first optical depth (surface waters). The coupling of both means of observations is essential for understanding phytoplankton dynamics and their response to environmental change. Here, we use 23 years of remotely sensed, regionally tuned ocean-colour observations, along with a unique time series of in situ phytoplankton pigment composition data, collected in coastal waters of Cyprus during 2016. The satellite observations show an initiation of phytoplankton growth period in November, a peak in February and termination in April, with an overall mean duration of textasciitilde4 months. An in-depth exploration of in situ total Chl-a concentration and phytoplankton pigments revealed that pico- and nano-plankton cells dominated the phytoplankton community. The growth peak in February was dominated by nanophytoplankton and potentially larger diatoms (pigments of 19’ hexanoyloxyfucoxanthin and fucoxanthin, respectively), in the 0–20 m layer. The highest total Chl-a concentration was recorded at a station off Akrotiri peninsula in the south, where strong coastal upwelling has been reported. Another station in the southern part, located next to a fish farm, showed a higher contribution of picophytoplankton during the most oligotrophic period (summer). Our results highlight the importance of using available in situ data coupled to ocean-colour remote sensing, for monitoring marine ecosystems in areas with limited in situ data availability. |
Puzenat, Valentine; Escartín, Javier; Martelat, Jean-Emmanuel; Barreyre, Thibaut; Bauer, Sven Le Moine; Nomikou, Paraskevi; Gracias, Nuno; Allemand, Pascal; Antoniou, Varvara; Coskun, Omer; Garcia, Rafael; Grandjean, Philippe; Jørgensen, Steffen Leth; Magí, Lluís; Mandalakis, Manolis; Orsi, William; Polymenakou, Paraskevi; Schouw, Anders; Vallicrosa, Guillem; Vlasopoulos, Othonas Shallow-water hydrothermalism at Milos (Greece): Nature, distribution, heat fluxes and impact on ecosystems Journal Article Marine Geology, 438 , pp. 106521, 2021, ISSN: 00253227. @article{puzenat_shallow-water_2021, title = {Shallow-water hydrothermalism at Milos (Greece): Nature, distribution, heat fluxes and impact on ecosystems}, author = {Valentine Puzenat and Javier Escartín and Jean-Emmanuel Martelat and Thibaut Barreyre and Sven Le Moine Bauer and Paraskevi Nomikou and Nuno Gracias and Pascal Allemand and Varvara Antoniou and Omer Coskun and Rafael Garcia and Philippe Grandjean and Steffen Leth Jørgensen and Lluís Magí and Manolis Mandalakis and William Orsi and Paraskevi Polymenakou and Anders Schouw and Guillem Vallicrosa and Othonas Vlasopoulos}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0025322721001031}, doi = {10.1016/j.margeo.2021.106521}, issn = {00253227}, year = {2021}, date = {2021-01-01}, urldate = {2022-02-22}, journal = {Marine Geology}, volume = {438}, pages = {106521}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2020 |
Polymenakou, Paraskevi N; Mandalakis, Manolis; Macheras, Michalis; Oulas, Anastasis; Kristoffersen, Jon Bent; Christakis, Christos A; Terzoglou, Vasso; Stavroulaki, Melanthia High genetic diversity and variability of microbial communities in near-surface atmosphere of Crete island, Greece Journal Article Aerobiologia, 36 (3), pp. 341–353, 2020, ISSN: 0393-5965, 1573-3025. @article{polymenakou_high_2020, title = {High genetic diversity and variability of microbial communities in near-surface atmosphere of Crete island, Greece}, author = {Paraskevi N Polymenakou and Manolis Mandalakis and Michalis Macheras and Anastasis Oulas and Jon Bent Kristoffersen and Christos A Christakis and Vasso Terzoglou and Melanthia Stavroulaki}, url = {http://link.springer.com/10.1007/s10453-020-09636-w}, doi = {10.1007/s10453-020-09636-w}, issn = {0393-5965, 1573-3025}, year = {2020}, date = {2020-09-01}, urldate = {2020-08-31}, journal = {Aerobiologia}, volume = {36}, number = {3}, pages = {341--353}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Rotter, Ana; Bacu, Ariola; Barbier, Michèle; Bertoni, Francesco; Bones, Atle M; Cancela, Leonor M; Carlsson, Jens; Carvalho, Maria F; Cegłowska, Marta; Dalay, Meltem Conk; Dailianis, Thanos; Deniz, Irem; Drakulovic, Dragana; Dubnika, Arita; Einarsson, Hjörleifur; Erdoğan, Ayşegül; Eroldoğan, Orhan Tufan; Ezra, David; Fazi, Stefano; FitzGerald, Richard J; Gargan, Laura M; Gaudêncio, Susana P; DeNardis, Nadica Ivošević; Joksimovic, Danijela; Kataržytė, Marija; Kotta, Jonne; Mandalakis, Manolis; Matijošytė, Inga; Mazur-Marzec, Hanna; Massa-Gallucci, Alexia; Mehiri, Mohamed; Nielsen, Søren Laurentius; Novoveská, Lucie; Overlingė, Donata; Portman, Michelle E; Pyrc, Krzysztof; Rebours, Céline; Reinsch, Thorsten; Reyes, Fernando; Rinkevich, Baruch; Robbens, Johan; Rudovica, Vita; Sabotič, Jerica; Safarik, Ivo; Talve, Siret; Tasdemir, Deniz; Schneider, Xenia Theodotou; Thomas, Olivier P; Toruńska-Sitarz, Anna; Varese, Giovanna Cristina; Vasquez, Marlen I A New Network for the Advancement of Marine Biotechnology in Europe and Beyond Journal Article Frontiers in Marine Science, 7 , pp. 278, 2020, ISSN: 2296-7745. @article{rotter_new_2020, title = {A New Network for the Advancement of Marine Biotechnology in Europe and Beyond}, author = {Ana Rotter and Ariola Bacu and Michèle Barbier and Francesco Bertoni and Atle M Bones and Leonor M Cancela and Jens Carlsson and Maria F Carvalho and Marta Cegłowska and Meltem Conk Dalay and Thanos Dailianis and Irem Deniz and Dragana Drakulovic and Arita Dubnika and Hjörleifur Einarsson and Ayşegül Erdoğan and Orhan Tufan Eroldoğan and David Ezra and Stefano Fazi and Richard J FitzGerald and Laura M Gargan and Susana P Gaudêncio and Nadica Ivošević DeNardis and Danijela Joksimovic and Marija Kataržytė and Jonne Kotta and Manolis Mandalakis and Inga Matijošytė and Hanna Mazur-Marzec and Alexia Massa-Gallucci and Mohamed Mehiri and Søren Laurentius Nielsen and Lucie Novoveská and Donata Overlingė and Michelle E Portman and Krzysztof Pyrc and Céline Rebours and Thorsten Reinsch and Fernando Reyes and Baruch Rinkevich and Johan Robbens and Vita Rudovica and Jerica Sabotič and Ivo Safarik and Siret Talve and Deniz Tasdemir and Xenia Theodotou Schneider and Olivier P Thomas and Anna Toruńska-Sitarz and Giovanna Cristina Varese and Marlen I Vasquez}, url = {https://www.frontiersin.org/article/10.3389/fmars.2020.00278}, doi = {10.3389/fmars.2020.00278}, issn = {2296-7745}, year = {2020}, date = {2020-01-01}, journal = {Frontiers in Marine Science}, volume = {7}, pages = {278}, abstract = {Marine organisms produce a vast diversity of metabolites with biological activities useful for humans, e.g., cytotoxic, antioxidant, anti-microbial, insecticidal, herbicidal, anticancer, pro-osteogenic and pro-regenerative, analgesic, anti-inflammatory, anti-coagulant, cholesterol-lowering, nutritional, photoprotective, horticultural or other beneficial properties. These metabolites could help satisfy the increasing demand for alternative sources of nutraceuticals, pharmaceuticals, cosmeceuticals, food, feed, and novel bio-based products. In addition, marine biomass itself can serve as the source material for the production of various bulk commodities (e.g., biofuels, bioplastics, biomaterials). The sustainable exploitation of marine bio-resources and the development of biomolecules and polymers are also known as the growing field of marine biotechnology. Up to now, over 35,000 natural products have been characterized from marine organisms, but many more are yet to be uncovered, as the vast diversity of biota in the marine systems remains largely unexplored. Since marine biotechnology is still in its infancy, there is a need to create effective, operational, inclusive, sustainable, transnational and transdisciplinary networks with a serious and ambitious commitment for knowledge transfer, training provision, dissemination of best practices and identification of the emerging technological trends through science communication activities. A collaborative (net)work is today compelling to provide innovative solutions and products that can be commercialized to contribute to the circular bioeconomy. This perspective article highlights the importance of establishing such collaborative frameworks using the example of Ocean4Biotech, an Action within the European Cooperation in Science and Technology (COST) that connects all and any stakeholders with an interest in marine biotechnology in Europe and beyond.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Marine organisms produce a vast diversity of metabolites with biological activities useful for humans, e.g., cytotoxic, antioxidant, anti-microbial, insecticidal, herbicidal, anticancer, pro-osteogenic and pro-regenerative, analgesic, anti-inflammatory, anti-coagulant, cholesterol-lowering, nutritional, photoprotective, horticultural or other beneficial properties. These metabolites could help satisfy the increasing demand for alternative sources of nutraceuticals, pharmaceuticals, cosmeceuticals, food, feed, and novel bio-based products. In addition, marine biomass itself can serve as the source material for the production of various bulk commodities (e.g., biofuels, bioplastics, biomaterials). The sustainable exploitation of marine bio-resources and the development of biomolecules and polymers are also known as the growing field of marine biotechnology. Up to now, over 35,000 natural products have been characterized from marine organisms, but many more are yet to be uncovered, as the vast diversity of biota in the marine systems remains largely unexplored. Since marine biotechnology is still in its infancy, there is a need to create effective, operational, inclusive, sustainable, transnational and transdisciplinary networks with a serious and ambitious commitment for knowledge transfer, training provision, dissemination of best practices and identification of the emerging technological trends through science communication activities. A collaborative (net)work is today compelling to provide innovative solutions and products that can be commercialized to contribute to the circular bioeconomy. This perspective article highlights the importance of establishing such collaborative frameworks using the example of Ocean4Biotech, an Action within the European Cooperation in Science and Technology (COST) that connects all and any stakeholders with an interest in marine biotechnology in Europe and beyond. |
Priede, Imants G; Burgass, Rhoderick W; Mandalakis, Manolis; Spyros, Apostolos; Gikas, Petros; Burns, Finlay; Drewery, Jim Near-equal compressibility of liver oil and seawater minimises buoyancy changes in deep-sea sharks and chimaeras Journal Article Journal of Experimental Biology, 223 (9), 2020, ISSN: 0022-0949, (Publisher: The Company of Biologists Ltd _eprint: https://jeb.biologists.org/content/223/9/jeb222943.full.pdf). @article{priede_near-equal_2020, title = {Near-equal compressibility of liver oil and seawater minimises buoyancy changes in deep-sea sharks and chimaeras}, author = {Imants G Priede and Rhoderick W Burgass and Manolis Mandalakis and Apostolos Spyros and Petros Gikas and Finlay Burns and Jim Drewery}, url = {https://jeb.biologists.org/content/223/9/jeb222943}, doi = {10.1242/jeb.222943}, issn = {0022-0949}, year = {2020}, date = {2020-01-01}, journal = {Journal of Experimental Biology}, volume = {223}, number = {9}, abstract = {Whereas upper ocean pelagic sharks are negatively buoyant and must swim continuously to generate lift from their fins, deep-sea sharks float or swim slowly buoyed up by large volumes of low-density oils in their livers. Investigation of the pressure, volume, temperature (PVT) relationships for liver oils of 10 species of deep-sea Chondrichthyes shows that the density difference between oil and seawater, Δρ, remains almost constant with pressure down to full ocean depth (11 km, 1100 bar), theoretically providing buoyancy far beyond the maximum depth of occurrence (3700 m) of sharks. However, Δρ does change significantly with temperature and we show that the combined effects of pressure and temperature can decrease buoyancy of oil by up to 10% between the surface and 3500 m depth across interfaces between warm southern and cold polar waters in the Rockall Trough in the NE Atlantic. This increases drag more than 10-fold compared with neutral buoyancy during horizontal slow swimming (0.1 m s-1), but the effect becomes negligible at high speeds. Chondrichthyes generally experience positive buoyancy change during ascent and negative buoyancy change during descent, but contrary effects can occur at interfaces between waters of different densities. During normal vertical migrations buoyancy changes are small, increasing slow-speed drag no more than 2- to 3-fold. Equations and tables of density, pressure and temperature are provided for squalene and liver oils of Chimaeriformes (Harriotta raleighana, Chimaera monstrosa, Hydrolagus affinis), Squaliformes (Centrophorus squamosus, Deania calcea, Centroscymnus coelolepis, Centroscyllium fabricii, Etmopterus spinax) and Carcharhiniformes (Apristurus laurussonii, Galeus murinus).}, note = {Publisher: The Company of Biologists Ltd _eprint: https://jeb.biologists.org/content/223/9/jeb222943.full.pdf}, keywords = {}, pubstate = {published}, tppubtype = {article} } Whereas upper ocean pelagic sharks are negatively buoyant and must swim continuously to generate lift from their fins, deep-sea sharks float or swim slowly buoyed up by large volumes of low-density oils in their livers. Investigation of the pressure, volume, temperature (PVT) relationships for liver oils of 10 species of deep-sea Chondrichthyes shows that the density difference between oil and seawater, Δρ, remains almost constant with pressure down to full ocean depth (11 km, 1100 bar), theoretically providing buoyancy far beyond the maximum depth of occurrence (3700 m) of sharks. However, Δρ does change significantly with temperature and we show that the combined effects of pressure and temperature can decrease buoyancy of oil by up to 10% between the surface and 3500 m depth across interfaces between warm southern and cold polar waters in the Rockall Trough in the NE Atlantic. This increases drag more than 10-fold compared with neutral buoyancy during horizontal slow swimming (0.1 m s-1), but the effect becomes negligible at high speeds. Chondrichthyes generally experience positive buoyancy change during ascent and negative buoyancy change during descent, but contrary effects can occur at interfaces between waters of different densities. During normal vertical migrations buoyancy changes are small, increasing slow-speed drag no more than 2- to 3-fold. Equations and tables of density, pressure and temperature are provided for squalene and liver oils of Chimaeriformes (Harriotta raleighana, Chimaera monstrosa, Hydrolagus affinis), Squaliformes (Centrophorus squamosus, Deania calcea, Centroscymnus coelolepis, Centroscyllium fabricii, Etmopterus spinax) and Carcharhiniformes (Apristurus laurussonii, Galeus murinus). |
Oikonomou, Andreas; Livanou, Eleni; Mandalakis, Manolis; Lagaria, Anna; Psarra, Stella Grazing effect of flagellates on bacteria in response to phosphate addition in the oligotrophic Cretan Sea, NE Mediterranean Journal Article FEMS Microbiology Ecology, 96 (6), 2020, ISSN: 0168-6496, (_eprint: https://academic.oup.com/femsec/article-pdf/96/6/fiaa086/33242983/fiaa086.pdf). @article{oikonomou_grazing_2020, title = {Grazing effect of flagellates on bacteria in response to phosphate addition in the oligotrophic Cretan Sea, NE Mediterranean}, author = {Andreas Oikonomou and Eleni Livanou and Manolis Mandalakis and Anna Lagaria and Stella Psarra}, url = {https://doi.org/10.1093/femsec/fiaa086}, doi = {10.1093/femsec/fiaa086}, issn = {0168-6496}, year = {2020}, date = {2020-01-01}, journal = {FEMS Microbiology Ecology}, volume = {96}, number = {6}, abstract = {The planktonic food web in the oligotrophic Mediterranean Sea is dominated by small-sized (<20 μm) microbes, with nanoflagellates being the major bacterial grazers and the main participants in nutrient cycling. Phosphate is a key nutrient in the P-limited Cretan Sea (NE Mediterranean) and P-availability can affect its trophic dynamics. Here, we examined the grazing potential of heterotrophic (HF) and pigmented (PF) nanoflagellates as a response mechanism to phosphate amendment. Flagellate grazing effect on bacteria was quantified in P-amended nutrient-depleted water from the Cretan Sea over the course of 4 days using microcosm experiments. P-addition positively affected HF abundance, while PF abundance remained unchanged. At the community level, P-addition had a negative effect on PF bacterial removal rates. In the control, PF-grazing rate was significantly higher than that of HF throughout the experiment. Pigment analysis showed no changes in phytoplankton community composition as a result of P-addition, indicating that PF grazing rate declined as a physiological response of the cells. The present study emphasizes the dominant grazing role of PF under P-depleted conditions and reveals that during the late stratified season PF respond to P-addition by lowering their grazing rates, enhancing the relative importance of bacterial removal by HF.}, note = {_eprint: https://academic.oup.com/femsec/article-pdf/96/6/fiaa086/33242983/fiaa086.pdf}, keywords = {}, pubstate = {published}, tppubtype = {article} } The planktonic food web in the oligotrophic Mediterranean Sea is dominated by small-sized (<20 μm) microbes, with nanoflagellates being the major bacterial grazers and the main participants in nutrient cycling. Phosphate is a key nutrient in the P-limited Cretan Sea (NE Mediterranean) and P-availability can affect its trophic dynamics. Here, we examined the grazing potential of heterotrophic (HF) and pigmented (PF) nanoflagellates as a response mechanism to phosphate amendment. Flagellate grazing effect on bacteria was quantified in P-amended nutrient-depleted water from the Cretan Sea over the course of 4 days using microcosm experiments. P-addition positively affected HF abundance, while PF abundance remained unchanged. At the community level, P-addition had a negative effect on PF bacterial removal rates. In the control, PF-grazing rate was significantly higher than that of HF throughout the experiment. Pigment analysis showed no changes in phytoplankton community composition as a result of P-addition, indicating that PF grazing rate declined as a physiological response of the cells. The present study emphasizes the dominant grazing role of PF under P-depleted conditions and reveals that during the late stratified season PF respond to P-addition by lowering their grazing rates, enhancing the relative importance of bacterial removal by HF. |
Polymenakou, Paraskevi N; Nomikou, Paraskevi; Mandalakis, Manolis; Kilias, Stephanos; Kotoulas, Giorgos; Kyrpides, Nikos C; Magoulas, Antonios Microbial Benthic Communities in the Aegean Sea Incollection Springer Berlin Heidelberg, Berlin, Heidelberg, 2020, (Series Title: The Handbook of Environmental Chemistry). @incollection{polymenakou_microbial_2020, title = {Microbial Benthic Communities in the Aegean Sea}, author = {Paraskevi N Polymenakou and Paraskevi Nomikou and Manolis Mandalakis and Stephanos Kilias and Giorgos Kotoulas and Nikos C Kyrpides and Antonios Magoulas}, url = {https://link.springer.com/10.1007/698_2020_685}, doi = {10.1007/698_2020_685}, year = {2020}, date = {2020-01-01}, urldate = {2022-02-17}, publisher = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, note = {Series Title: The Handbook of Environmental Chemistry}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } |
2019 |
Anastasiou, Thekla I; Mandalakis, Manolis; Krigas, Nikos; Vézignol, Thomas; Lazari, Diamanto; Katharios, Pantelis; Dailianis, Thanos; Antonopoulou, Efthimia Molecules, 25 (1), pp. 148, 2019, ISSN: 1420-3049. @article{anastasiou_comparative_2019, title = {Comparative Evaluation of Essential Oils from Medicinal-Aromatic Plants of Greece: Chemical Composition, Antioxidant Capacity and Antimicrobial Activity against Bacterial Fish Pathogens}, author = {Thekla I Anastasiou and Manolis Mandalakis and Nikos Krigas and Thomas Vézignol and Diamanto Lazari and Pantelis Katharios and Thanos Dailianis and Efthimia Antonopoulou}, url = {https://www.mdpi.com/1420-3049/25/1/148}, doi = {10.3390/molecules25010148}, issn = {1420-3049}, year = {2019}, date = {2019-12-01}, urldate = {2020-08-09}, journal = {Molecules}, volume = {25}, number = {1}, pages = {148}, abstract = {The administration of antibiotics in aquaculture has raised concern about the impact of their overuse in marine ecosystems, seafood safety and consumers’ health. This “green consumerism” has forced researchers to find new alternatives against fish pathogens. The present study focused on 12 Mediterranean medicinal-aromatic plants as potential antimicrobials and antioxidant agents that could be used in fish aquaculture. In vitro assays showed that the essential oils (EOs) from all studied plants had anti-bacterial and antioxidant properties, with their efficacy being dependent on their chemical composition. More specifically, EOs rich in carvacrol, p-cymene and γ-terpinene exhibited not only the strongest inhibitory activity against the growth of bacterial pathogens (inhibitory concentration: 26–88 μg mL−1), but also the greatest total antioxidant capacity (ABTS: 2591–5879 μmole mL−1; CUPRAC: 931–2733 μmole mL−1). These compounds were mainly found in the EOs from Greek oregano (Origanum vulgare subsp. hirtum), Spanish oregano (Thymbra capitata) and savoury (Satureja thymbra) collected from cultivations in Greece. The specific EOs stand out as promising candidates for the treatment of bacterial diseases and oxidative stress in farmed fish. Further in vivo experiments are needed to fully understand the effects of EO dietary supplementation on fish farming processes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The administration of antibiotics in aquaculture has raised concern about the impact of their overuse in marine ecosystems, seafood safety and consumers’ health. This “green consumerism” has forced researchers to find new alternatives against fish pathogens. The present study focused on 12 Mediterranean medicinal-aromatic plants as potential antimicrobials and antioxidant agents that could be used in fish aquaculture. In vitro assays showed that the essential oils (EOs) from all studied plants had anti-bacterial and antioxidant properties, with their efficacy being dependent on their chemical composition. More specifically, EOs rich in carvacrol, p-cymene and γ-terpinene exhibited not only the strongest inhibitory activity against the growth of bacterial pathogens (inhibitory concentration: 26–88 μg mL−1), but also the greatest total antioxidant capacity (ABTS: 2591–5879 μmole mL−1; CUPRAC: 931–2733 μmole mL−1). These compounds were mainly found in the EOs from Greek oregano (Origanum vulgare subsp. hirtum), Spanish oregano (Thymbra capitata) and savoury (Satureja thymbra) collected from cultivations in Greece. The specific EOs stand out as promising candidates for the treatment of bacterial diseases and oxidative stress in farmed fish. Further in vivo experiments are needed to fully understand the effects of EO dietary supplementation on fish farming processes. |
Vitali, Francesco; Mandalakis, Manolis; Chatzinikolaou, Eva; Dailianis, Thanos; Senatore, Giuliana; Casalone, Enrico; Mastromei, Giorgio; Sergi, Simona; Lussu, Raffaela; Arvanitidis, Christos; Tamburini, Elena Frontiers in Marine Science, 6 , pp. 590, 2019, ISSN: 2296-7745. @article{vitali_benthic_2019, title = {Benthic Prokaryotic Community Response to Polycyclic Aromatic Hydrocarbon Chronic Exposure: Importance of Emission Sources in Mediterranean Ports}, author = {Francesco Vitali and Manolis Mandalakis and Eva Chatzinikolaou and Thanos Dailianis and Giuliana Senatore and Enrico Casalone and Giorgio Mastromei and Simona Sergi and Raffaela Lussu and Christos Arvanitidis and Elena Tamburini}, url = {https://www.frontiersin.org/article/10.3389/fmars.2019.00590/full}, doi = {10.3389/fmars.2019.00590}, issn = {2296-7745}, year = {2019}, date = {2019-09-01}, urldate = {2020-08-06}, journal = {Frontiers in Marine Science}, volume = {6}, pages = {590}, abstract = {The present study aimed to evaluate the impact of polycyclic aromatic hydrocarbons (PAHs) produced by multiple emission sources on prokaryotic communities in sediments chronically affected by anthropogenic pressures. In this context, surface sediments were investigated in three Mediterranean touristic ports over three sampling periods and in different port sectors. The levels of 16 priority PAHs varied over three orders of magnitude (25–49,000 ng g–1) covering the range of concentrations previously reported for Mediterranean harbors. Pyrogenic processes were found to be the dominant emission source of PAHs, with considerable differences among ports. The prokaryotic communities were identified by using the terminal restriction fragment length polymorphism, targeting the 16S rRNA gene for Bacteria and Archaea as well as the dsrAB gene for sulphate-reducing bacteria (SRB). The structure of the three benthic prokaryotic communities varied consistently among the ports. The structure of Bacteria and Archaea exhibited strong spatiotemporal variations that did not allow us to specifically link the observed differences in community structures with PAH sources. On the contrary, our study provided, for the first time, evidence that the PAH emission sources play a role in structuring benthic communities of SRB. Our findings indicate that the SRB community can be used as a valuable candidate biotic descriptor for bioremediation monitoring in heavily impacted port sediments.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present study aimed to evaluate the impact of polycyclic aromatic hydrocarbons (PAHs) produced by multiple emission sources on prokaryotic communities in sediments chronically affected by anthropogenic pressures. In this context, surface sediments were investigated in three Mediterranean touristic ports over three sampling periods and in different port sectors. The levels of 16 priority PAHs varied over three orders of magnitude (25–49,000 ng g–1) covering the range of concentrations previously reported for Mediterranean harbors. Pyrogenic processes were found to be the dominant emission source of PAHs, with considerable differences among ports. The prokaryotic communities were identified by using the terminal restriction fragment length polymorphism, targeting the 16S rRNA gene for Bacteria and Archaea as well as the dsrAB gene for sulphate-reducing bacteria (SRB). The structure of the three benthic prokaryotic communities varied consistently among the ports. The structure of Bacteria and Archaea exhibited strong spatiotemporal variations that did not allow us to specifically link the observed differences in community structures with PAH sources. On the contrary, our study provided, for the first time, evidence that the PAH emission sources play a role in structuring benthic communities of SRB. Our findings indicate that the SRB community can be used as a valuable candidate biotic descriptor for bioremediation monitoring in heavily impacted port sediments. |
Livanou, Eleni; Lagaria, Anna; Santi, Ioulia; Mandalakis, Manolis; Pavlidou, Alexandra; Lika, Konstadia; Psarra, Stella Deep-Sea Research Part II: Topical Studies in Oceanography, 164 , pp. 100–111, 2019, ISSN: 09670645, (Publisher: Pergamon). @article{livanou_pigmented_2019, title = {Pigmented and heterotrophic nanoflagellates: Abundance and grazing on prokaryotic picoplankton in the ultra-oligotrophic Eastern Mediterranean Sea}, author = {Eleni Livanou and Anna Lagaria and Ioulia Santi and Manolis Mandalakis and Alexandra Pavlidou and Konstadia Lika and Stella Psarra}, url = {https://www.sciencedirect.com/science/article/pii/S096706451930027X?dgcid=coauthor}, doi = {10.1016/j.dsr2.2019.04.007}, issn = {09670645}, year = {2019}, date = {2019-04-01}, journal = {Deep-Sea Research Part II: Topical Studies in Oceanography}, volume = {164}, pages = {100--111}, abstract = {The abundance and grazing effect of small (textbackslashtextless5 μm) pigmented (PNF) and heterotrophic (HNF) nanoflagellates on prokaryotic picoplankton stock (i.e. heterotrophic bacteria (HB) and Synechococcus) were assessed during April 2016 at four stations along a longitudinal transect in the ultra-oligotrophic Eastern Mediterranean Sea and at two selected depths with varying nutrient and light conditions; the 5 m depth representing surface water and the 75 m depth representing the deeper euphotic layer, targeting the Deep Chlorophyll Maximum (DCM) zone at the sampling stations. Cells of size textbackslashtextless3 μm dominated the small nanoflagellate community and accounted for 84 ± 8.2% and 73 ± 12.2% (mean ± sd) of total HNF and PNF, respectively. HNF abundance and their grazing effect on prokaryotic picoplankton did not differ between the two depths, while PNF exhibited higher abundance and grazing effect on prokaryotic picoplankton at 75 m compared to the surface (5 m). HNF dominated prokaryotic picoplankton consumption at 5 m accounting for 67–92% and 71–90% of the HB and Synechococcus consumption, respectively. On the other hand, PNF were the dominant grazers of prokaryotic picoplankton at 75 m accounting for 72–80% of the HB consumption and 60–74% of the Synechococcus consumption. HNF and PNF together consumed 4.4 ± 3.2% d −1 (mean ± sd) of the HB standing stock and 19.7 ± 16% d −1 (mean ± sd) of the Synechococcus standing stock. Moreover, a negative relationship between phosphate concentration and ingestion rates of PNF on prokaryotic picoplankton was observed. Pigment analysis showed that the major PNF groups were Prymnesiophytes followed by Pelagophytes/Chrysophytes. Prymnesiophytes was the group mostly associated with mixotrophy. Overall, our results pinpoint the role of small nanoflagellates as prokaryotic picoplankton consumers and the importance of mixotrophy as a trophic mode for PNF in the ultra-oligotrophic E. Mediterranean Sea.}, note = {Publisher: Pergamon}, keywords = {}, pubstate = {published}, tppubtype = {article} } The abundance and grazing effect of small (textbackslashtextless5 μm) pigmented (PNF) and heterotrophic (HNF) nanoflagellates on prokaryotic picoplankton stock (i.e. heterotrophic bacteria (HB) and Synechococcus) were assessed during April 2016 at four stations along a longitudinal transect in the ultra-oligotrophic Eastern Mediterranean Sea and at two selected depths with varying nutrient and light conditions; the 5 m depth representing surface water and the 75 m depth representing the deeper euphotic layer, targeting the Deep Chlorophyll Maximum (DCM) zone at the sampling stations. Cells of size textbackslashtextless3 μm dominated the small nanoflagellate community and accounted for 84 ± 8.2% and 73 ± 12.2% (mean ± sd) of total HNF and PNF, respectively. HNF abundance and their grazing effect on prokaryotic picoplankton did not differ between the two depths, while PNF exhibited higher abundance and grazing effect on prokaryotic picoplankton at 75 m compared to the surface (5 m). HNF dominated prokaryotic picoplankton consumption at 5 m accounting for 67–92% and 71–90% of the HB and Synechococcus consumption, respectively. On the other hand, PNF were the dominant grazers of prokaryotic picoplankton at 75 m accounting for 72–80% of the HB consumption and 60–74% of the Synechococcus consumption. HNF and PNF together consumed 4.4 ± 3.2% d −1 (mean ± sd) of the HB standing stock and 19.7 ± 16% d −1 (mean ± sd) of the Synechococcus standing stock. Moreover, a negative relationship between phosphate concentration and ingestion rates of PNF on prokaryotic picoplankton was observed. Pigment analysis showed that the major PNF groups were Prymnesiophytes followed by Pelagophytes/Chrysophytes. Prymnesiophytes was the group mostly associated with mixotrophy. Overall, our results pinpoint the role of small nanoflagellates as prokaryotic picoplankton consumers and the importance of mixotrophy as a trophic mode for PNF in the ultra-oligotrophic E. Mediterranean Sea. |
Rizzo, Andrea Luca; Caracausi, Antonio; Chavagnac, Valérie; Nomikou, Paraskevi; Polymenakou, Paraskevi N; Mandalakis, Manolis; Kotoulas, Georgios; Magoulas, Antonios; Castillo, Alain; Lampridou, Danai; Marusczak, Nicolas; Sonke, Jeroen E Geochemistry of CO2-Rich Gases Venting From Submarine Volcanism: The Case of Kolumbo (Hellenic Volcanic Arc, Greece) Journal Article Frontiers in Earth Science, 7 , pp. 60, 2019, ISSN: 2296-6463, (BIODIV). @article{rizzo_geochemistry_2019, title = {Geochemistry of CO2-Rich Gases Venting From Submarine Volcanism: The Case of Kolumbo (Hellenic Volcanic Arc, Greece)}, author = {Andrea Luca Rizzo and Antonio Caracausi and Valérie Chavagnac and Paraskevi Nomikou and Paraskevi N Polymenakou and Manolis Mandalakis and Georgios Kotoulas and Antonios Magoulas and Alain Castillo and Danai Lampridou and Nicolas Marusczak and Jeroen E Sonke}, url = {https://www.frontiersin.org/article/10.3389/feart.2019.00060/full}, doi = {10.3389/feart.2019.00060}, issn = {2296-6463}, year = {2019}, date = {2019-04-01}, urldate = {2022-01-17}, journal = {Frontiers in Earth Science}, volume = {7}, pages = {60}, note = {BIODIV}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Mandalakis, M; Gavriilidou, A; Polymenakou, P N; Christakis, C A; Nomikou, P; Medvecký, M; Kilias, S P; Kentouri, M; Kotoulas, G; Magoulas, A Microbial strains isolated from CO2-venting Kolumbo submarine volcano show enhanced co-tolerance to acidity and antibiotics Journal Article Marine Environmental Research, 2019, ISSN: 01411136, (Publisher: Elsevier Ltd). @article{mandalakis_microbial_2019, title = {Microbial strains isolated from CO2-venting Kolumbo submarine volcano show enhanced co-tolerance to acidity and antibiotics}, author = {M Mandalakis and A Gavriilidou and P N Polymenakou and C A Christakis and P Nomikou and M Medvecký and S P Kilias and M Kentouri and G Kotoulas and A Magoulas}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059814164&doi=10.1016%2fj.marenvres.2019.01.002&partnerID=40&md5=69e25c6daab89af12b0091a2c75b0d18}, doi = {10.1016/j.marenvres.2019.01.002}, issn = {01411136}, year = {2019}, date = {2019-01-01}, journal = {Marine Environmental Research}, abstract = {As ocean acidification intensifies, there is growing global concern about the impacts that future pH levels are likely to have on marine life and ecosystems. By analogy, a steep decrease of seawater pH with depth is encountered inside the Kolumbo submarine volcano (northeast Santorini) as a result of natural CO2 venting, making this system ideal for ocean acidification research. Here, we investigated whether the increase of acidity towards deeper layers of Kolumbo crater had any effect on relevant phenotypic traits of bacterial isolates. A total of 31 Pseudomonas strains were isolated from both surface- (SSL) and deep-seawater layers (DSL), with the latter presenting a significantly higher acid tolerance. In particular, the DSL strains were able to cope with H+ levels that were 18 times higher. Similarly, the DSL isolates exhibited a significantly higher tolerance than SSL strains against six commonly used antibiotics and As(III). More importantly, a significant positive correlation was revealed between antibiotics and acid tolerance across the entire set of SSL and DSL isolates. Our findings imply that Pseudomonas species with higher resilience to antibiotics could be favored by the prospect of acidifying oceans. Further studies are required to determine if this feature is universal across marine bacteria and to assess potential ecological impacts. © 2019 Elsevier Ltd}, note = {Publisher: Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } As ocean acidification intensifies, there is growing global concern about the impacts that future pH levels are likely to have on marine life and ecosystems. By analogy, a steep decrease of seawater pH with depth is encountered inside the Kolumbo submarine volcano (northeast Santorini) as a result of natural CO2 venting, making this system ideal for ocean acidification research. Here, we investigated whether the increase of acidity towards deeper layers of Kolumbo crater had any effect on relevant phenotypic traits of bacterial isolates. A total of 31 Pseudomonas strains were isolated from both surface- (SSL) and deep-seawater layers (DSL), with the latter presenting a significantly higher acid tolerance. In particular, the DSL strains were able to cope with H+ levels that were 18 times higher. Similarly, the DSL isolates exhibited a significantly higher tolerance than SSL strains against six commonly used antibiotics and As(III). More importantly, a significant positive correlation was revealed between antibiotics and acid tolerance across the entire set of SSL and DSL isolates. Our findings imply that Pseudomonas species with higher resilience to antibiotics could be favored by the prospect of acidifying oceans. Further studies are required to determine if this feature is universal across marine bacteria and to assess potential ecological impacts. © 2019 Elsevier Ltd |
2018 |
Polymenakou, Paraskevi; Mandalakis, Manolis; Dailianis, Thanos; Dimitriadis, Charalampos; Medvecky, Matej; Magoulas, Antonios; Gerovasileiou, Vasilis Preliminary assessment of methanogenic microbial communities in marine caves of Zakynthos Island (Ionian Sea, Greece) Journal Article Mediterranean Marine Science, pp. 284, 2018, ISSN: 1791-6763, 1108-393X. @article{polymenakou_preliminary_2018, title = {Preliminary assessment of methanogenic microbial communities in marine caves of Zakynthos Island (Ionian Sea, Greece)}, author = {Paraskevi Polymenakou and Manolis Mandalakis and Thanos Dailianis and Charalampos Dimitriadis and Matej Medvecky and Antonios Magoulas and Vasilis Gerovasileiou}, url = {https://ejournals.epublishing.ekt.gr/index.php/hcmr-med-mar-sc/article/view/14374}, doi = {10.12681/mms.14374}, issn = {1791-6763, 1108-393X}, year = {2018}, date = {2018-06-01}, urldate = {2020-08-06}, journal = {Mediterranean Marine Science}, pages = {284}, abstract = {Mediterranean marine caves remain largely unexplored, while particularly limited information is available about the microbial life existing in these unique environments. The present study is a preliminary assessment of the composition of the active anaerobic microbial community colonizing the walls of newly explored systems of underwater caves and small cavities in Zakynthos Island. The interior of these caves is densely coated with egg-shaped, foam-shaped and filamentous biological structures that are characterised by a strong odor of hydrogen sulfide gas. A total of twelve structures scrapped from cave rocks were subjected to anaerobic cultivation for up to 208 days. Strong to moderate methanogenesis was observed in two different types of egg-shaped structures and one foam-like structure. Interestingly, this was observed in experiments that were performed at room temperature (i.e. 25oC) which is substantially lower than those typically considered optimum for methane production (e.g. 35oC). Analysis of the 16S rRNA genes revealed a clear dominance of archaea and bacteria closely related to known methane producers and sulfate reducers, including members of the families Methanomicrobiaceae, Desulfobulbaceae, Desulfobacteraceae, Desulfuromonaceae, Campylobacteraceae, Marinifilaceae, Clostridiaceae, Incertae Sedis – Family I & II. These results show that Mediterranean marine caves can host members of archaea and bacteria with potential biotechnological interest that deserve further investigation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Mediterranean marine caves remain largely unexplored, while particularly limited information is available about the microbial life existing in these unique environments. The present study is a preliminary assessment of the composition of the active anaerobic microbial community colonizing the walls of newly explored systems of underwater caves and small cavities in Zakynthos Island. The interior of these caves is densely coated with egg-shaped, foam-shaped and filamentous biological structures that are characterised by a strong odor of hydrogen sulfide gas. A total of twelve structures scrapped from cave rocks were subjected to anaerobic cultivation for up to 208 days. Strong to moderate methanogenesis was observed in two different types of egg-shaped structures and one foam-like structure. Interestingly, this was observed in experiments that were performed at room temperature (i.e. 25oC) which is substantially lower than those typically considered optimum for methane production (e.g. 35oC). Analysis of the 16S rRNA genes revealed a clear dominance of archaea and bacteria closely related to known methane producers and sulfate reducers, including members of the families Methanomicrobiaceae, Desulfobulbaceae, Desulfobacteraceae, Desulfuromonaceae, Campylobacteraceae, Marinifilaceae, Clostridiaceae, Incertae Sedis – Family I & II. These results show that Mediterranean marine caves can host members of archaea and bacteria with potential biotechnological interest that deserve further investigation. |
Christakis, C A; Polymenakou, P N; Mandalakis, M; Nomikou, P; Kristoffersen, J B; Lampridou, D; Kotoulas, G; Magoulas, A Microbial community differentiation between active and inactive sulfide chimneys of the Kolumbo submarine volcano, Hellenic Volcanic Arc Journal Article Extremophiles, 22 (1), pp. 13–27, 2018, ISSN: 14310651, (Publisher: Springer Tokyo). @article{christakis_microbial_2018, title = {Microbial community differentiation between active and inactive sulfide chimneys of the Kolumbo submarine volcano, Hellenic Volcanic Arc}, author = {C A Christakis and P N Polymenakou and M Mandalakis and P Nomikou and J B Kristoffersen and D Lampridou and G Kotoulas and A Magoulas}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032008505&doi=10.1007%2fs00792-017-0971-x&partnerID=40&md5=2258d2985b658c3f415f37d92d684597}, doi = {10.1007/s00792-017-0971-x}, issn = {14310651}, year = {2018}, date = {2018-01-01}, journal = {Extremophiles}, volume = {22}, number = {1}, pages = {13--27}, abstract = {Over the last decades, there has been growing interest about the ecological role of hydrothermal sulfide chimneys, their microbial diversity and associated biotechnological potential. Here, we performed dual-index Illumina sequencing of bacterial and archaeal communities on active and inactive sulfide chimneys collected from the Kolumbo hydrothermal field, situated on a geodynamic convergent setting. A total of 15,701 OTUs (operational taxonomic units) were assigned to 56 bacterial and 3 archaeal phyla, 133 bacterial and 16 archaeal classes. Active chimney communities were dominated by OTUs related to thermophilic members of Epsilonproteobacteria, Aquificae and Deltaproteobacteria. Inactive chimney communities were dominated by an OTU closely related to the archaeon Nitrosopumilus sp., and by members of Gammaproteobacteria, Deltaproteobacteria, Planctomycetes and Bacteroidetes. These lineages are closely related to phylotypes typically involved in iron, sulfur, nitrogen, hydrogen and methane cycling. Overall, the inactive sulfide chimneys presented highly diverse and uniform microbial communities, in contrast to the active chimney communities, which were dominated by chemolithoautotrophic and thermophilic lineages. This study represents one of the most comprehensive investigations of microbial diversity in submarine chimneys and elucidates how the dissipation of hydrothermal activity affects the structure of microbial consortia in these extreme ecological niches. © 2017, Springer Japan KK.}, note = {Publisher: Springer Tokyo}, keywords = {}, pubstate = {published}, tppubtype = {article} } Over the last decades, there has been growing interest about the ecological role of hydrothermal sulfide chimneys, their microbial diversity and associated biotechnological potential. Here, we performed dual-index Illumina sequencing of bacterial and archaeal communities on active and inactive sulfide chimneys collected from the Kolumbo hydrothermal field, situated on a geodynamic convergent setting. A total of 15,701 OTUs (operational taxonomic units) were assigned to 56 bacterial and 3 archaeal phyla, 133 bacterial and 16 archaeal classes. Active chimney communities were dominated by OTUs related to thermophilic members of Epsilonproteobacteria, Aquificae and Deltaproteobacteria. Inactive chimney communities were dominated by an OTU closely related to the archaeon Nitrosopumilus sp., and by members of Gammaproteobacteria, Deltaproteobacteria, Planctomycetes and Bacteroidetes. These lineages are closely related to phylotypes typically involved in iron, sulfur, nitrogen, hydrogen and methane cycling. Overall, the inactive sulfide chimneys presented highly diverse and uniform microbial communities, in contrast to the active chimney communities, which were dominated by chemolithoautotrophic and thermophilic lineages. This study represents one of the most comprehensive investigations of microbial diversity in submarine chimneys and elucidates how the dissipation of hydrothermal activity affects the structure of microbial consortia in these extreme ecological niches. © 2017, Springer Japan KK. |
Chatzinikolaou, E; Mandalakis, M; Damianidis, P; Dailianis, T; Gambineri, S; Rossano, C; Scapini, F; Carucci, A; Arvanitidis, C Spatio-temporal benthic biodiversity patterns and pollution pressure in three Mediterranean touristic ports Journal Article Science of the Total Environment, 624 , pp. 648–660, 2018, ISSN: 00489697, (Publisher: Elsevier B.V.). @article{chatzinikolaou_spatio-temporal_2018, title = {Spatio-temporal benthic biodiversity patterns and pollution pressure in three Mediterranean touristic ports}, author = {E Chatzinikolaou and M Mandalakis and P Damianidis and T Dailianis and S Gambineri and C Rossano and F Scapini and A Carucci and C Arvanitidis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038809023&doi=10.1016%2fj.scitotenv.2017.12.111&partnerID=40&md5=e7ce64fb16c0df8f7d6cc0aea715e447}, doi = {10.1016/j.scitotenv.2017.12.111}, issn = {00489697}, year = {2018}, date = {2018-01-01}, journal = {Science of the Total Environment}, volume = {624}, pages = {648--660}, abstract = {The Mediterranean Sea is one of the busiest areas worldwide in terms of maritime activity, facing considerable anthropogenic disturbance, such as pollution by hydrocarbons and heavy metals. The present study has evaluated the environmental and benthic biodiversity characteristics of three touristic ports, Cagliari (Sardinia, Italy), Heraklion (Crete, Greece) and El Kantaoui (Tunisia), based on the combined assessment of physical parameters, chemical variables (i.e. nutrients, pigments), sediment pollution and macrobenthic biodiversity. Different port sectors (leisure, fishing, passenger, cargo, shipyard) and different seasons (winter, before touristic period, after touristic period) were compared. Salinity and sediment concentration of copper and antimony were the three environmental parameters most highly correlated with benthic species composition and diversity. Both the environmental variables and the benthic biodiversity patterns were significantly different between the three ports (i.e. different geographical locations). Heraklion port was heavily polluted by AHs in surface and anoxic sediments and had the highest percentage of opportunistic species, while Cagliari had the highest levels of PAHs and UCM and low species richness. El Kantaoui port was less polluted and characterised by a richer biodiversity. The shipyard sector in Heraklion port was significantly different from all other sectors in terms of abiotic and biotic parameters. Physico-chemical and pollution variables recorded during the period after tourism (late summer) were significantly different from the ones recorded in winter. Seasonal differences were not significant between benthic species diversity patterns, but were revealed when the patterns derived from the aggregation of higher taxonomic levels were compared. The present study indicates that a regular-basis monitoring plan including evaluation of environmental health based on benthic biodiversity, can provide a basis for perceiving changes and reveal the degree of anthropogenic disturbance in port environments. © 2017 Elsevier B.V.}, note = {Publisher: Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Mediterranean Sea is one of the busiest areas worldwide in terms of maritime activity, facing considerable anthropogenic disturbance, such as pollution by hydrocarbons and heavy metals. The present study has evaluated the environmental and benthic biodiversity characteristics of three touristic ports, Cagliari (Sardinia, Italy), Heraklion (Crete, Greece) and El Kantaoui (Tunisia), based on the combined assessment of physical parameters, chemical variables (i.e. nutrients, pigments), sediment pollution and macrobenthic biodiversity. Different port sectors (leisure, fishing, passenger, cargo, shipyard) and different seasons (winter, before touristic period, after touristic period) were compared. Salinity and sediment concentration of copper and antimony were the three environmental parameters most highly correlated with benthic species composition and diversity. Both the environmental variables and the benthic biodiversity patterns were significantly different between the three ports (i.e. different geographical locations). Heraklion port was heavily polluted by AHs in surface and anoxic sediments and had the highest percentage of opportunistic species, while Cagliari had the highest levels of PAHs and UCM and low species richness. El Kantaoui port was less polluted and characterised by a richer biodiversity. The shipyard sector in Heraklion port was significantly different from all other sectors in terms of abiotic and biotic parameters. Physico-chemical and pollution variables recorded during the period after tourism (late summer) were significantly different from the ones recorded in winter. Seasonal differences were not significant between benthic species diversity patterns, but were revealed when the patterns derived from the aggregation of higher taxonomic levels were compared. The present study indicates that a regular-basis monitoring plan including evaluation of environmental health based on benthic biodiversity, can provide a basis for perceiving changes and reveal the degree of anthropogenic disturbance in port environments. © 2017 Elsevier B.V. |
Kokkari, C; Sarropoulou, E; Bastias, R; Mandalakis, M; Katharios, P Isolation and characterization of a novel bacteriophage infecting Vibrio alginolyticus Journal Article Archives of Microbiology, 200 (5), pp. 707–718, 2018, ISSN: 03028933, (Publisher: Springer Verlag). @article{kokkari_isolation_2018, title = {Isolation and characterization of a novel bacteriophage infecting Vibrio alginolyticus}, author = {C Kokkari and E Sarropoulou and R Bastias and M Mandalakis and P Katharios}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040930909&doi=10.1007%2fs00203-018-1480-8&partnerID=40&md5=b22268a55a9ed98e93e66d4448fbe221}, doi = {10.1007/s00203-018-1480-8}, issn = {03028933}, year = {2018}, date = {2018-01-01}, journal = {Archives of Microbiology}, volume = {200}, number = {5}, pages = {707--718}, abstract = {Vibrio alginolyticus is a common marine bacterium implicated in disease outbreaks in marine farmed fish and invertebrates. Due to the inappropriate use of antibiotics in aquaculture, alternative therapies have been proposed. One of the most promising options is the use of lytic bacteriophages to control pathogenic bacteria. This work describes the isolation and characterization of a lytic phage (VEN) against a V. alginolyticus strain (V2) isolated from a disease outbreak in common dentex (Dentex dentex) cultured at the Hellenic Centre for Marine Research (HCMR) in Crete, Greece. The bacteriophage is morphologically similar to phages from Podoviridae family and remained stable for 1 year at 4 °C and over 1 h when kept at 50 °C. VEN was able to lyse the host bacteria at several multiplicity of infection (MOI) (0.1–100) in liquid cultures. However, it was unable to infect other V. alginolyticus strains. Its genome consists of 44,603 bp with a GC content of 43.5%, while sequence analysis revealed the presence of 54 potential ORFs with a T7-like genomic organization. Almost 65% of the predicted ORFs presented homology with proteins of the vibriophages Vc1 and phi-A318 infecting Vibrio cyclitrophicus and Vibrio alginolyticus, respectively. Phylogenetic analysis applying the amino acid sequence of the large terminase subunit confirmed the close relationship of these phages. Furthermore, the comparison of the RNA polymerase of these phages revealed that the motifs A, B and C related to the catalytic activity and the recognition loop related to promotor identification were also conserved. VEN has an obligate lytic life cycle demonstrated by experimental data and genomic analysis. These results suggest that VEN may provide a good candidate to control recurrent diseases caused by V. alginolyticus at HCMR. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.}, note = {Publisher: Springer Verlag}, keywords = {}, pubstate = {published}, tppubtype = {article} } Vibrio alginolyticus is a common marine bacterium implicated in disease outbreaks in marine farmed fish and invertebrates. Due to the inappropriate use of antibiotics in aquaculture, alternative therapies have been proposed. One of the most promising options is the use of lytic bacteriophages to control pathogenic bacteria. This work describes the isolation and characterization of a lytic phage (VEN) against a V. alginolyticus strain (V2) isolated from a disease outbreak in common dentex (Dentex dentex) cultured at the Hellenic Centre for Marine Research (HCMR) in Crete, Greece. The bacteriophage is morphologically similar to phages from Podoviridae family and remained stable for 1 year at 4 °C and over 1 h when kept at 50 °C. VEN was able to lyse the host bacteria at several multiplicity of infection (MOI) (0.1–100) in liquid cultures. However, it was unable to infect other V. alginolyticus strains. Its genome consists of 44,603 bp with a GC content of 43.5%, while sequence analysis revealed the presence of 54 potential ORFs with a T7-like genomic organization. Almost 65% of the predicted ORFs presented homology with proteins of the vibriophages Vc1 and phi-A318 infecting Vibrio cyclitrophicus and Vibrio alginolyticus, respectively. Phylogenetic analysis applying the amino acid sequence of the large terminase subunit confirmed the close relationship of these phages. Furthermore, the comparison of the RNA polymerase of these phages revealed that the motifs A, B and C related to the catalytic activity and the recognition loop related to promotor identification were also conserved. VEN has an obligate lytic life cycle demonstrated by experimental data and genomic analysis. These results suggest that VEN may provide a good candidate to control recurrent diseases caused by V. alginolyticus at HCMR. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. |
Mandalakis, M; Panikov, N S; Polymenakou, P N; Sizova, M V; Stamatakis, A A simple cleanup method for the removal of humic substances from soil protein extracts using aluminum coagulation Journal Article Environmental Science and Pollution Research, 25 (24), pp. 23845–23856, 2018, ISSN: 09441344, (Publisher: Springer Verlag). @article{mandalakis_simple_2018, title = {A simple cleanup method for the removal of humic substances from soil protein extracts using aluminum coagulation}, author = {M Mandalakis and N S Panikov and P N Polymenakou and M V Sizova and A Stamatakis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048049746&doi=10.1007%2fs11356-018-2434-z&partnerID=40&md5=eb9d45b91caf01d89a3baea78220a432}, doi = {10.1007/s11356-018-2434-z}, issn = {09441344}, year = {2018}, date = {2018-01-01}, journal = {Environmental Science and Pollution Research}, volume = {25}, number = {24}, pages = {23845--23856}, abstract = {Soil proteomics, the large-scale characterization of the entire protein complement in soils, provides a promising approach for deciphering the role of microbial functioning in terrestrial ecosystems. However, the extraction of soil proteins in sufficient quantities and of adequate purity remains a challenging task mainly due to the co-extraction of interfering humic substances. Up to now, the treatment of soil extracts with liquid phenol has been the “gold standard” for reducing humics, while the NoviPure cleanup kit was recently launched as a non-toxic approach. The present study describes an alternative method for delivering high-purity proteins based on humic coagulation with trivalent aluminum ions (Al3+). Various experimental parameters were optimized individually in order to maximize protein yield and diminish co-extracted humics. The optimized method was applied on a set of soil samples with diverse physicochemical characteristics and a comparison with the other two techniques was conducted. The amount of residual humics resulting from Al3+-based method was 26 and 35% higher than that from phenol treatment and NoviPure Kit, respectively, but these differences were of marginal statistical significance. With regard to extracted proteins, the average yields of the three methods were comparable, without showing any statistically significant differences. Overall, humic coagulation with Al3+ offers comparable cleanup performance in terms of protein yield and purity, but it is less toxic and less complex than the phenol-partitioning method, whereas it is far less expensive than the NoviPure Kit. The new technique is expected to facilitate the implementation of proteomic studies in soils. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.}, note = {Publisher: Springer Verlag}, keywords = {}, pubstate = {published}, tppubtype = {article} } Soil proteomics, the large-scale characterization of the entire protein complement in soils, provides a promising approach for deciphering the role of microbial functioning in terrestrial ecosystems. However, the extraction of soil proteins in sufficient quantities and of adequate purity remains a challenging task mainly due to the co-extraction of interfering humic substances. Up to now, the treatment of soil extracts with liquid phenol has been the “gold standard” for reducing humics, while the NoviPure cleanup kit was recently launched as a non-toxic approach. The present study describes an alternative method for delivering high-purity proteins based on humic coagulation with trivalent aluminum ions (Al3+). Various experimental parameters were optimized individually in order to maximize protein yield and diminish co-extracted humics. The optimized method was applied on a set of soil samples with diverse physicochemical characteristics and a comparison with the other two techniques was conducted. The amount of residual humics resulting from Al3+-based method was 26 and 35% higher than that from phenol treatment and NoviPure Kit, respectively, but these differences were of marginal statistical significance. With regard to extracted proteins, the average yields of the three methods were comparable, without showing any statistically significant differences. Overall, humic coagulation with Al3+ offers comparable cleanup performance in terms of protein yield and purity, but it is less toxic and less complex than the phenol-partitioning method, whereas it is far less expensive than the NoviPure Kit. The new technique is expected to facilitate the implementation of proteomic studies in soils. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. |
2017 |
Lagaria, A; Mandalakis, M; Mara, P; Papageorgiou, N; Pitta, P; Tsiola, A; Kagiorgi, M; Psarra, S Phytoplankton response to Saharan dust depositions in the Eastern Mediterranean Sea: A mesocosm study Journal Article Frontiers in Marine Science, 3 , pp. 287, 2017, ISSN: 22967745, (Publisher: Frontiers Media S. A). @article{lagaria_phytoplankton_2017, title = {Phytoplankton response to Saharan dust depositions in the Eastern Mediterranean Sea: A mesocosm study}, author = {A Lagaria and M Mandalakis and P Mara and N Papageorgiou and P Pitta and A Tsiola and M Kagiorgi and S Psarra}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85015289914&doi=10.3389%2fFMARS.2016.00287&partnerID=40&md5=3b66cf0631eb4cf99802a9b13cb4af20}, doi = {10.3389/FMARS.2016.00287}, issn = {22967745}, year = {2017}, date = {2017-01-01}, journal = {Frontiers in Marine Science}, volume = {3}, pages = {287}, abstract = {The response of phytoplankton populations from surface ultra-oligotrophic waters of the Eastern Mediterranean Sea to Saharan dust additions was studied during a 10-day mesocosm experiment in May 2014. A set of triplicate mesocosms entitled "Single Addition" treatment (SA) was amended with Saharan dust once, while another triplicate set entitled "Repetitive Addition" treatment (RA) received the same amount of dust divided into three consecutive daily doses administered within the first three experimental days, both simulating patterns of dust deposition events taking place in the field. In both treatments, dust particles released small amounts of dissolved inorganic nitrogen and phosphorus which stimulated by 2-fold both chlorophyll-a concentration and primary production for a time period of 6 days, as compared to a set of control mesocosms carried out without dust addition. Phytoplankton response was similar in both treatments, regardless of the dust addition pattern, and it evolved through two distinct phases in both cases. The first phase (i.e., 1-2 days after initial addition) was characterized by enhancement of picoplankton chlorophyll-normalized production rates as a result of elevated orthophosphate concentrations while the second phase (i.e., 3-4 days after initial dust addition), was characterized by elevated chlorophyll-normalized production rates corresponding to larger cells (textgreater 5 μm) as a result of increased mineral nitrogen concentrations. The stimulated primary production of larger cells was not accompanied by a respective increase in carbon biomass suggesting important top-down control. The major phytoplankton taxa detected during the experiment were Synechococcus, Pelagophytes, and Prymnesiophytes. Estimations of cellular pigment concentrations and carbon-to-chlorophyll ratios of identified groups and differences between prokaryotic and eukaryotic cells are discussed. © 2017 Lagaria, Mandalakis, Mara, Papageorgiou, Pitta, Tsiola, Kagiorgi and Psarra.}, note = {Publisher: Frontiers Media S. A}, keywords = {}, pubstate = {published}, tppubtype = {article} } The response of phytoplankton populations from surface ultra-oligotrophic waters of the Eastern Mediterranean Sea to Saharan dust additions was studied during a 10-day mesocosm experiment in May 2014. A set of triplicate mesocosms entitled "Single Addition" treatment (SA) was amended with Saharan dust once, while another triplicate set entitled "Repetitive Addition" treatment (RA) received the same amount of dust divided into three consecutive daily doses administered within the first three experimental days, both simulating patterns of dust deposition events taking place in the field. In both treatments, dust particles released small amounts of dissolved inorganic nitrogen and phosphorus which stimulated by 2-fold both chlorophyll-a concentration and primary production for a time period of 6 days, as compared to a set of control mesocosms carried out without dust addition. Phytoplankton response was similar in both treatments, regardless of the dust addition pattern, and it evolved through two distinct phases in both cases. The first phase (i.e., 1-2 days after initial addition) was characterized by enhancement of picoplankton chlorophyll-normalized production rates as a result of elevated orthophosphate concentrations while the second phase (i.e., 3-4 days after initial dust addition), was characterized by elevated chlorophyll-normalized production rates corresponding to larger cells (textgreater 5 μm) as a result of increased mineral nitrogen concentrations. The stimulated primary production of larger cells was not accompanied by a respective increase in carbon biomass suggesting important top-down control. The major phytoplankton taxa detected during the experiment were Synechococcus, Pelagophytes, and Prymnesiophytes. Estimations of cellular pigment concentrations and carbon-to-chlorophyll ratios of identified groups and differences between prokaryotic and eukaryotic cells are discussed. © 2017 Lagaria, Mandalakis, Mara, Papageorgiou, Pitta, Tsiola, Kagiorgi and Psarra. |
Mandalakis, M; Stravinskaitė, A; Lagaria, A; Psarra, S; Polymenakou, P Ultrasensitive and high-throughput analysis of chlorophyll a in marine phytoplankton extracts using a fluorescence microplate reader Journal Article Analytical and Bioanalytical Chemistry, 409 (19), pp. 4539–4549, 2017, ISSN: 16182642, (Publisher: Springer Verlag). @article{mandalakis_ultrasensitive_2017, title = {Ultrasensitive and high-throughput analysis of chlorophyll a in marine phytoplankton extracts using a fluorescence microplate reader}, author = {M Mandalakis and A Stravinskaitė and A Lagaria and S Psarra and P Polymenakou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019571709&doi=10.1007%2fs00216-017-0392-9&partnerID=40&md5=17de4972e6106b13bb3f85822323f8b2}, doi = {10.1007/s00216-017-0392-9}, issn = {16182642}, year = {2017}, date = {2017-01-01}, journal = {Analytical and Bioanalytical Chemistry}, volume = {409}, number = {19}, pages = {4539--4549}, abstract = {Chlorophyll a (Chl a) is the predominant pigment in every single photosynthesizing organism including phytoplankton and one of the most commonly measured water quality parameters. Various methods are available for Chl a analysis, but the majority of them are of limited throughput and require considerable effort and time from the operator. The present study describes a high-throughput, microplate-based fluorometric assay for rapid quantification of Chl a in phytoplankton extracts. Microplate sealing combined with ice cooling was proved an effective means for diminishing solvent evaporation during sample loading and minimized the analytical errors involved in Chl a measurements with a fluorescence microplate reader. A set of operating parameters (settling time, detector gain, sample volume) were also optimized to further improve the intensity and reproducibility of Chl a fluorescence signal. A quadratic regression model provided the best fit (r2 = 0.9998) across the entire calibration range (0.05–240 pg μL−1). The method offered excellent intra- and interday precision (% RSD 2.2 to 11.2%) and accuracy (% relative error −3.8 to 13.8%), while it presented particularly low limits of detection (0.044 pg μL−1) and quantification (0.132 pg μL−1). The present assay was successfully applied on marine phytoplankton extracts, and the overall results were consistent (average % relative error −14.8%) with Chl a concentrations (including divinyl Chl a) measured by high-performance liquid chromatography (HPLC). More importantly, the microplate-based method allowed the analysis of 96 samples/standards within a few minutes, instead of hours or days, when using a traditional cuvette-based fluorometer or an HPLC system. [Figure not available: see fulltext.]. © 2017, Springer-Verlag Berlin Heidelberg.}, note = {Publisher: Springer Verlag}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chlorophyll a (Chl a) is the predominant pigment in every single photosynthesizing organism including phytoplankton and one of the most commonly measured water quality parameters. Various methods are available for Chl a analysis, but the majority of them are of limited throughput and require considerable effort and time from the operator. The present study describes a high-throughput, microplate-based fluorometric assay for rapid quantification of Chl a in phytoplankton extracts. Microplate sealing combined with ice cooling was proved an effective means for diminishing solvent evaporation during sample loading and minimized the analytical errors involved in Chl a measurements with a fluorescence microplate reader. A set of operating parameters (settling time, detector gain, sample volume) were also optimized to further improve the intensity and reproducibility of Chl a fluorescence signal. A quadratic regression model provided the best fit (r2 = 0.9998) across the entire calibration range (0.05–240 pg μL−1). The method offered excellent intra- and interday precision (% RSD 2.2 to 11.2%) and accuracy (% relative error −3.8 to 13.8%), while it presented particularly low limits of detection (0.044 pg μL−1) and quantification (0.132 pg μL−1). The present assay was successfully applied on marine phytoplankton extracts, and the overall results were consistent (average % relative error −14.8%) with Chl a concentrations (including divinyl Chl a) measured by high-performance liquid chromatography (HPLC). More importantly, the microplate-based method allowed the analysis of 96 samples/standards within a few minutes, instead of hours or days, when using a traditional cuvette-based fluorometer or an HPLC system. [Figure not available: see fulltext.]. © 2017, Springer-Verlag Berlin Heidelberg. |
Lagaria, A; Mandalakis, M; Mara, P; Frangoulis, C; Karatsolis, B -T; Pitta, P; Triantaphyllou, M; Tsiola, A; Psarra, S Phytoplankton variability and community structure in relation to hydrographic features in the NE Aegean frontal area (NE Mediterranean Sea) Journal Article Continental Shelf Research, 149 , pp. 124–137, 2017, ISSN: 02784343, (Publisher: Elsevier Ltd). @article{lagaria_phytoplankton_2017-1, title = {Phytoplankton variability and community structure in relation to hydrographic features in the NE Aegean frontal area (NE Mediterranean Sea)}, author = {A Lagaria and M Mandalakis and P Mara and C Frangoulis and B -T Karatsolis and P Pitta and M Triantaphyllou and A Tsiola and S Psarra}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84996539987&doi=10.1016%2fj.csr.2016.07.014&partnerID=40&md5=ef7234614afbfd8579b69deef5768c78}, doi = {10.1016/j.csr.2016.07.014}, issn = {02784343}, year = {2017}, date = {2017-01-01}, journal = {Continental Shelf Research}, volume = {149}, pages = {124--137}, abstract = {The structure of phytoplankton community in the salinity-stratified Northeastern Aegean frontal area adjacent to the Dardanelles Straits was investigated on a seasonal basis (autumn, spring and summer) and in relation to circulating water masses: the modified Black Sea Water (BSW) and the Levantine Water (LW). By employing High Performance Liquid Chromatography (HPLC) for the analysis of phytoplankton pigments in conjunction with conventional cell counting methodologies (i.e. inverted light microscopy, flow cytometry) and primary production measurements, a comprehensive qualitative and quantitative characterization of phytoplankton community composition and its activity was conducted. Chlorophyll-a normalized production and estimated growth rates presented the highest values within the ‘fresh’ BSW mass during summer, though generally growth rates were low (<0.4 d−1) at all seasons. The spatiotemporal variation of BSW outflow was found to greatly affect the relative contribution of pico-, nano- and micro-phytoplankton to total phytoplankton biomass and production. Large cell organisms, and in particular diatoms, were closely associated with the surface BSW masses outflowing from the Straits. Our results showed that all phytoplankton size components were significant over time and space suggesting a rather multivorous food web functioning of the system. © 2016 Elsevier Ltd}, note = {Publisher: Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } The structure of phytoplankton community in the salinity-stratified Northeastern Aegean frontal area adjacent to the Dardanelles Straits was investigated on a seasonal basis (autumn, spring and summer) and in relation to circulating water masses: the modified Black Sea Water (BSW) and the Levantine Water (LW). By employing High Performance Liquid Chromatography (HPLC) for the analysis of phytoplankton pigments in conjunction with conventional cell counting methodologies (i.e. inverted light microscopy, flow cytometry) and primary production measurements, a comprehensive qualitative and quantitative characterization of phytoplankton community composition and its activity was conducted. Chlorophyll-a normalized production and estimated growth rates presented the highest values within the ‘fresh’ BSW mass during summer, though generally growth rates were low (<0.4 d−1) at all seasons. The spatiotemporal variation of BSW outflow was found to greatly affect the relative contribution of pico-, nano- and micro-phytoplankton to total phytoplankton biomass and production. Large cell organisms, and in particular diatoms, were closely associated with the surface BSW masses outflowing from the Straits. Our results showed that all phytoplankton size components were significant over time and space suggesting a rather multivorous food web functioning of the system. © 2016 Elsevier Ltd |
2016 |
Oulas, Anastasis; Polymenakou, Paraskevi N; Seshadri, Rekha; Tripp, James H; Mandalakis, Manolis; Paez-Espino, David A; Pati, Amrita; Chain, Patrick; Nomikou, Paraskevi; Carey, Steven; Kilias, Stephanos; Christakis, Christos; Kotoulas, Georgios; Magoulas, Antonios; Ivanova, Natalia N; Kyrpides, Nikos C Metagenomic investigation of the geologically unique Hellenic Volcanic Arc reveals a distinctive ecosystem with unexpected physiology. Journal Article Environmental Microbiology, 18 (4), pp. 1122–1136, 2016, ISSN: 1462-2920. @article{oulas_metagenomic_2016, title = {Metagenomic investigation of the geologically unique Hellenic Volcanic Arc reveals a distinctive ecosystem with unexpected physiology.}, author = {Anastasis Oulas and Paraskevi N Polymenakou and Rekha Seshadri and James H Tripp and Manolis Mandalakis and David A Paez-Espino and Amrita Pati and Patrick Chain and Paraskevi Nomikou and Steven Carey and Stephanos Kilias and Christos Christakis and Georgios Kotoulas and Antonios Magoulas and Natalia N Ivanova and Nikos C Kyrpides}, url = {http://www.ncbi.nlm.nih.gov/pubmed/26487573}, doi = {10.1111/1462-2920.13095}, issn = {1462-2920}, year = {2016}, date = {2016-01-01}, journal = {Environmental Microbiology}, volume = {18}, number = {4}, pages = {1122--1136}, abstract = {Hydrothermal vents represent a deep, hot, aphotic biosphere where chemosynthetic primary producers, fuelled by chemicals from Earth's subsurface, form the basis of life. In this study, we examined microbial mats from two distinct volcanic sites within the Hellenic Volcanic Arc (HVA). The HVA is geologically and ecologically unique, with reported emissions of CO2 -saturated fluids at temperatures up to 220°C and a notable absence of macrofauna. Metagenomic data reveals highly complex prokaryotic communities composed of chemolithoautotrophs, some methanotrophs, and to our surprise, heterotrophs capable of anaerobic degradation of aromatic hydrocarbons. Our data suggest that aromatic hydrocarbons may indeed be a significant source of carbon in these sites, and instigate additional research into the nature and origin of these compounds in the HVA. Novel physiology was assigned to several uncultured prokaryotic lineages; most notably, a SAR406 representative is attributed with a role in anaerobic hydrocarbon degradation. This dataset, the largest to date from submarine volcanic ecosystems, constitutes a significant resource of novel genes and pathways with potential biotechnological applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrothermal vents represent a deep, hot, aphotic biosphere where chemosynthetic primary producers, fuelled by chemicals from Earth's subsurface, form the basis of life. In this study, we examined microbial mats from two distinct volcanic sites within the Hellenic Volcanic Arc (HVA). The HVA is geologically and ecologically unique, with reported emissions of CO2 -saturated fluids at temperatures up to 220°C and a notable absence of macrofauna. Metagenomic data reveals highly complex prokaryotic communities composed of chemolithoautotrophs, some methanotrophs, and to our surprise, heterotrophs capable of anaerobic degradation of aromatic hydrocarbons. Our data suggest that aromatic hydrocarbons may indeed be a significant source of carbon in these sites, and instigate additional research into the nature and origin of these compounds in the HVA. Novel physiology was assigned to several uncultured prokaryotic lineages; most notably, a SAR406 representative is attributed with a role in anaerobic hydrocarbon degradation. This dataset, the largest to date from submarine volcanic ecosystems, constitutes a significant resource of novel genes and pathways with potential biotechnological applications. |
Anastasiou, T I; Chatzinikolaou, E; Mandalakis, M; Arvanitidis, C Imposex and organotin compounds in ports of the Mediterranean and the Atlantic: Is the story over? Journal Article Science of the Total Environment, 569-570 , pp. 1315–1329, 2016, ISSN: 00489697, (Publisher: Elsevier B.V.). @article{anastasiou_imposex_2016, title = {Imposex and organotin compounds in ports of the Mediterranean and the Atlantic: Is the story over?}, author = {T I Anastasiou and E Chatzinikolaou and M Mandalakis and C Arvanitidis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978807299&doi=10.1016%2fj.scitotenv.2016.06.209&partnerID=40&md5=f0a46f0f9141ca86261409181b4d0d9b}, doi = {10.1016/j.scitotenv.2016.06.209}, issn = {00489697}, year = {2016}, date = {2016-01-01}, journal = {Science of the Total Environment}, volume = {569-570}, pages = {1315--1329}, abstract = {Organotin compounds are toxic substances released into the marine environment from antifouling paints. Sixty-two years following their first application and 9 years after the complete ban on their use as biocides in 2003 (EC No. 782/2003), their negative impact on mollusks was still evident, as illustrated by imposex (i.e. the masculinization of female gastropods). This phenomenon is widely used to investigate tributyltin (TBT) pollution, with Hexaplex trunculus and Nassarius nitidus being considered as sensitive bioindicators. H. trunculus specimens and sediment samples collected from the ports of Cagliari (Sardinia), El Kantaoui (Tunisia) and Olhão (Portugal), along with N. nitidus individuals from the port of Faro (Portugal), were used for the assessment of imposex intensity and organotin pollution in these areas. High imposex frequency and organotin concentrations (TBT, triphenyltin (TPhT) and their degradation products) were observed, especially in Sardinia, implying that these chemicals remain a significant pollution issue in the specific Mediterranean ports. Moreover, the highly significant relationship established between penis length of imposex-affected females H. trunculus and TBT/TPhT concentrations offers a rapid and nonsacrificial proxy model for assessing the impact of organotins in coastal environments. Finally, the complementary use of more than one TBT bioindicator is advised in order to obtain more accurate results in detailed monitoring studies of TBT pollution. © 2016 Elsevier B.V.}, note = {Publisher: Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Organotin compounds are toxic substances released into the marine environment from antifouling paints. Sixty-two years following their first application and 9 years after the complete ban on their use as biocides in 2003 (EC No. 782/2003), their negative impact on mollusks was still evident, as illustrated by imposex (i.e. the masculinization of female gastropods). This phenomenon is widely used to investigate tributyltin (TBT) pollution, with Hexaplex trunculus and Nassarius nitidus being considered as sensitive bioindicators. H. trunculus specimens and sediment samples collected from the ports of Cagliari (Sardinia), El Kantaoui (Tunisia) and Olhão (Portugal), along with N. nitidus individuals from the port of Faro (Portugal), were used for the assessment of imposex intensity and organotin pollution in these areas. High imposex frequency and organotin concentrations (TBT, triphenyltin (TPhT) and their degradation products) were observed, especially in Sardinia, implying that these chemicals remain a significant pollution issue in the specific Mediterranean ports. Moreover, the highly significant relationship established between penis length of imposex-affected females H. trunculus and TBT/TPhT concentrations offers a rapid and nonsacrificial proxy model for assessing the impact of organotins in coastal environments. Finally, the complementary use of more than one TBT bioindicator is advised in order to obtain more accurate results in detailed monitoring studies of TBT pollution. © 2016 Elsevier B.V. |
Christopoulou, M E; Mertzimekis, T J; Nomikou, P; Papanikolaou, D; Carey, S; Mandalakis, M Influence of hydrothermal venting on water column properties in the crater of the Kolumbo submarine volcano, Santorini volcanic field (Greece) Journal Article Geo-Marine Letters, 36 (1), pp. 15–24, 2016, ISSN: 02760460, (Publisher: Springer Verlag). @article{christopoulou_influence_2016, title = {Influence of hydrothermal venting on water column properties in the crater of the Kolumbo submarine volcano, Santorini volcanic field (Greece)}, author = {M E Christopoulou and T J Mertzimekis and P Nomikou and D Papanikolaou and S Carey and M Mandalakis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955195173&doi=10.1007%2fs00367-015-0429-z&partnerID=40&md5=0ce02912dabd658b8747026a1d7ede9a}, doi = {10.1007/s00367-015-0429-z}, issn = {02760460}, year = {2016}, date = {2016-01-01}, journal = {Geo-Marine Letters}, volume = {36}, number = {1}, pages = {15--24}, abstract = {The Kolumbo submarine volcano, located 7 km northeast of the island of Santorini, is part of Santorini’s volcanic complex in the south Aegean Sea, Greece. Kolumbo’s last eruption was in 1650 AD. However, a unique and active hydrothermal vent field has been revealed in the northern part of its crater floor during an oceanographic survey by remotely operated vehicles (ROVs) in 2006. In the present study, conductivity-temperature-depth (CTD) data collected by ROV Hercules during three oceanographic surveys onboard E/V Nautilus in 2010 and 2011 have served to investigate the distribution of physicochemical properties in the water column, as well as their behavior directly over the hydrothermal field. Additional CTD measurements were carried out in volcanic cone 3 (VC3) along the same volcanic chain but located 3 km northeast of Kolumbo where no hydrothermal activity has been detected to date. CTD profiles exhibit pronounced anomalies directly above the active vents on Kolumbo’s crater floor. In contrast, VC3 data revealed no such anomalies, essentially resembling open-sea (background) conditions. Steep increases of temperature (e.g., from 16 to 19 °C) and conductivity near the maximum depth (504 m) inside Kolumbo’s cone show marked spatiotemporal correlation. Vertical distributions of CTD signatures suggest a strong connection to Kolumbo’s morphology, with four distinct zones identified (open sea, turbid flow, invariable state, hydrothermal vent field). Additionally, overlaying the near-seafloor temperature measurements on an X–Y coordinate grid generates a detailed 2D distribution of the hydrothermal vent field and clarifies the influence of fluid discharges in its formation. © 2015, Springer-Verlag Berlin Heidelberg.}, note = {Publisher: Springer Verlag}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Kolumbo submarine volcano, located 7 km northeast of the island of Santorini, is part of Santorini’s volcanic complex in the south Aegean Sea, Greece. Kolumbo’s last eruption was in 1650 AD. However, a unique and active hydrothermal vent field has been revealed in the northern part of its crater floor during an oceanographic survey by remotely operated vehicles (ROVs) in 2006. In the present study, conductivity-temperature-depth (CTD) data collected by ROV Hercules during three oceanographic surveys onboard E/V Nautilus in 2010 and 2011 have served to investigate the distribution of physicochemical properties in the water column, as well as their behavior directly over the hydrothermal field. Additional CTD measurements were carried out in volcanic cone 3 (VC3) along the same volcanic chain but located 3 km northeast of Kolumbo where no hydrothermal activity has been detected to date. CTD profiles exhibit pronounced anomalies directly above the active vents on Kolumbo’s crater floor. In contrast, VC3 data revealed no such anomalies, essentially resembling open-sea (background) conditions. Steep increases of temperature (e.g., from 16 to 19 °C) and conductivity near the maximum depth (504 m) inside Kolumbo’s cone show marked spatiotemporal correlation. Vertical distributions of CTD signatures suggest a strong connection to Kolumbo’s morphology, with four distinct zones identified (open sea, turbid flow, invariable state, hydrothermal vent field). Additionally, overlaying the near-seafloor temperature measurements on an X–Y coordinate grid generates a detailed 2D distribution of the hydrothermal vent field and clarifies the influence of fluid discharges in its formation. © 2015, Springer-Verlag Berlin Heidelberg. |
Rizzo, A L; Caracausi, A; Chavagnac, V; Nomikou, P; Polymenakou, P N; Mandalakis, M; Kotoulas, G; Magoulas, A; Castillo, A; Lampridou, D Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system Journal Article Scientific Reports, 6 , 2016, ISSN: 20452322, (Publisher: Nature Publishing Group). @article{rizzo_kolumbo_2016, title = {Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system}, author = {A L Rizzo and A Caracausi and V Chavagnac and P Nomikou and P N Polymenakou and M Mandalakis and G Kotoulas and A Magoulas and A Castillo and D Lampridou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975454736&doi=10.1038%2fsrep28013&partnerID=40&md5=e24dc2fa03414abaf410e586529f758d}, doi = {10.1038/srep28013}, issn = {20452322}, year = {2016}, date = {2016-01-01}, journal = {Scientific Reports}, volume = {6}, abstract = {Submarine volcanism represents ∼80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (∼220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10-6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.}, note = {Publisher: Nature Publishing Group}, keywords = {}, pubstate = {published}, tppubtype = {article} } Submarine volcanism represents ∼80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (∼220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10-6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano. |
Karatsolis, B T H; Dimiza, M; Nomikou, P; Polymenakou, P N; Mandalakis, M; Papanikolaou, D; Archontikis, O; Malinverno, E; Mertzimekis, T; Papa, E; Christopoulou, M E; Triantaphyllou, M V Possible effects of Kolumbo submarine volcano emissions (Cyclades, Aegean Sea) to plankton assemblages Inproceedings Chania, Crete, Greece, 2016, (Publication Title: 3nd International Geo-Cultural Symposium “CHANIA 2016”). @inproceedings{karatsolis_possible_2016, title = {Possible effects of Kolumbo submarine volcano emissions (Cyclades, Aegean Sea) to plankton assemblages}, author = {B T H Karatsolis and M Dimiza and P Nomikou and P N Polymenakou and M Mandalakis and D Papanikolaou and O Archontikis and E Malinverno and T Mertzimekis and E Papa and M E Christopoulou and M V Triantaphyllou}, year = {2016}, date = {2016-01-01}, address = {Chania, Crete, Greece}, note = {Publication Title: 3nd International Geo-Cultural Symposium “CHANIA 2016”}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Rizzo, A L; Caracausi, A; Chavagnac, V; Nomikou, P; Polymenakou, P N; Mandalakis, M; Kotoulas, Georgios; Magoulas, A; Castillo, A Kolumbo active seamount (Greece): a window into the Aegean mantle Inproceedings Nancy, France, 2016, (Publication Title: DINGUE ⋕4, Developments in Noble Gas Understanding and Expertise). @inproceedings{rizzo_kolumbo_2016-1, title = {Kolumbo active seamount (Greece): a window into the Aegean mantle}, author = {A L Rizzo and A Caracausi and V Chavagnac and P Nomikou and P N Polymenakou and M Mandalakis and Georgios Kotoulas and A Magoulas and A Castillo}, year = {2016}, date = {2016-01-01}, address = {Nancy, France}, note = {Publication Title: DINGUE ⋕4, Developments in Noble Gas Understanding and Expertise}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2015 |
Polymenakou, Paraskevi N; Christakis, Christos A; Mandalakis, Manolis; Oulas, Anastasis Pyrosequencing analysis of microbial communities reveals dominant cosmopolitan phylotypes in deep-sea sediments of the eastern Mediterranean Sea Journal Article Research in Microbiology, 166 (5), pp. 448–457, 2015, ISSN: 0923-2508. @article{polymenakou_pyrosequencing_2015, title = {Pyrosequencing analysis of microbial communities reveals dominant cosmopolitan phylotypes in deep-sea sediments of the eastern Mediterranean Sea}, author = {Paraskevi N Polymenakou and Christos A Christakis and Manolis Mandalakis and Anastasis Oulas}, url = {http://www.sciencedirect.com/science/article/pii/S0923250815000571}, doi = {http://dx.doi.org/10.1016/j.resmic.2015.03.005}, issn = {0923-2508}, year = {2015}, date = {2015-06-01}, journal = {Research in Microbiology}, volume = {166}, number = {5}, pages = {448--457}, abstract = {Abstract The deep eastern basin of the Mediterranean Sea is considered to be one of the world's most oligotrophic areas in the world. Here we performed pyrosequenicng analysis of bacterial and archaeal communities in oxic nutrient-poor sediments collected from the eastern Mediterranean at 1025–4393 m depth. Microbial communities were surveyed by targeting the hypervariable V5–V6 regions of the 16S ribosomal RNA gene using bar-coded pyrosequencing. With a total of 13,194 operational taxonomic units (OTUs) or phylotypes at 97% sequence similarities, the phylogenetic affiliation of microbes was assigned to 23 bacterial and 2 archaeal known phyla, 23 candidate divisions at the phylum level and distributed into 186 families. It was further revealed that the microbial consortia inhabiting all sampling sites were highly diverse, but dominated by phylotypes closely related to members of the genus Pseudomonas and Marine Group I archaea. Such pronounced and widespread enrichment probably manifests the cosmopolitan character of these species and raises questions about their metabolic adaptation to the physical stressors and low nutrient availability of the deep eastern Mediterranean Sea.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract The deep eastern basin of the Mediterranean Sea is considered to be one of the world's most oligotrophic areas in the world. Here we performed pyrosequenicng analysis of bacterial and archaeal communities in oxic nutrient-poor sediments collected from the eastern Mediterranean at 1025–4393 m depth. Microbial communities were surveyed by targeting the hypervariable V5–V6 regions of the 16S ribosomal RNA gene using bar-coded pyrosequencing. With a total of 13,194 operational taxonomic units (OTUs) or phylotypes at 97% sequence similarities, the phylogenetic affiliation of microbes was assigned to 23 bacterial and 2 archaeal known phyla, 23 candidate divisions at the phylum level and distributed into 186 families. It was further revealed that the microbial consortia inhabiting all sampling sites were highly diverse, but dominated by phylotypes closely related to members of the genus Pseudomonas and Marine Group I archaea. Such pronounced and widespread enrichment probably manifests the cosmopolitan character of these species and raises questions about their metabolic adaptation to the physical stressors and low nutrient availability of the deep eastern Mediterranean Sea. |
Ruggeri, C; Mandalakis, M; Sergi, S; Bullita, E; Frigau, N; Tamburini, E; Chatzinikolaou, E; Dailianis, T; Arvanitidis, C Characterisation of pollution status and hydrocarbon degraders in seawater of Mediterranean tourist ports Inproceedings 6th European Bioremediation Conference, pp. 596–600, Chania, Crete, Greece, 2015. @inproceedings{ruggeri_characterisation_2015, title = {Characterisation of pollution status and hydrocarbon degraders in seawater of Mediterranean tourist ports}, author = {C Ruggeri and M Mandalakis and S Sergi and E Bullita and N Frigau and E Tamburini and E Chatzinikolaou and T Dailianis and C Arvanitidis}, year = {2015}, date = {2015-01-01}, booktitle = {6th European Bioremediation Conference}, pages = {596--600}, address = {Chania, Crete, Greece}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Anastasiou, T; Chatzinikolaou, E; Mandalakis, M; Arvanitidis, C Imposex status and organotin concentrations in Hexaplex trunculus (Linnaeus, 1758) from the port of Cagliari (Sardinia) Inproceedings 11th Panhellenic Symposium on Oceanography and Fisheries, Mytilene, Greece, 2015. @inproceedings{anastasiou_imposex_2015, title = {Imposex status and organotin concentrations in Hexaplex trunculus (Linnaeus, 1758) from the port of Cagliari (Sardinia)}, author = {T Anastasiou and E Chatzinikolaou and M Mandalakis and C Arvanitidis}, year = {2015}, date = {2015-01-01}, booktitle = {11th Panhellenic Symposium on Oceanography and Fisheries}, address = {Mytilene, Greece}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Panikov, N S; Mandalakis, M; Dai, S; Mulcahy, L R; Fowle, W; Garrett, W S; Karger, B L Near-zero growth kinetics of Pseudomonas putida deduced from proteomic analysis Journal Article Environmental Microbiology, 17 (1), pp. 215–228, 2015, ISSN: 14622912, (Publisher: Blackwell Publishing Ltd). @article{panikov_near-zero_2015, title = {Near-zero growth kinetics of Pseudomonas putida deduced from proteomic analysis}, author = {N S Panikov and M Mandalakis and S Dai and L R Mulcahy and W Fowle and W S Garrett and B L Karger}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921819171&doi=10.1111%2f1462-2920.12584&partnerID=40&md5=1a150070e125eb5952c170115799aed4}, doi = {10.1111/1462-2920.12584}, issn = {14622912}, year = {2015}, date = {2015-01-01}, journal = {Environmental Microbiology}, volume = {17}, number = {1}, pages = {215--228}, abstract = {Intensive microbial growth typically observed in laboratory rarely occurs in nature. Because of severe nutrient deficiency, natural populations exhibit near-zero growth (NZG). There is a long-standing controversy about sustained NZG, specifically whether there is a minimum growth rate below which cells die or whether cells enter a non-growing maintenance state. Using chemostat with cell retention (CCR) of Pseudomonas putida, we resolve this controversy and show that under NZG conditions, bacteria differentiate into growing and VBNC (viable but not non-culturable) forms, the latter preserving measurable catabolic activity. The proliferating cells attained a steady state, their slow growth balanced by VBNC production. Proteomic analysis revealed upregulated (transporters, stress response, self-degrading enzymes and extracellular polymers) and downregulated (ribosomal, chemotactic and primary biosynthetic enzymes) proteins in the CCR versus batch culture. Based on these profiles, we identified intracellular processes associated with NZG and generated a mathematical model that simulated the observations. We conclude that NZG requires controlled partial self-digestion and deep reconfiguration of the metabolic machinery that results in the biosynthesis of new products and development of broad stress resistance. CCR allows efficient on-line control of NZG including VBNC production. A well-nuanced understanding of NZG is important to understand microbial processes in situ and for optimal design of environmental technologies. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.}, note = {Publisher: Blackwell Publishing Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Intensive microbial growth typically observed in laboratory rarely occurs in nature. Because of severe nutrient deficiency, natural populations exhibit near-zero growth (NZG). There is a long-standing controversy about sustained NZG, specifically whether there is a minimum growth rate below which cells die or whether cells enter a non-growing maintenance state. Using chemostat with cell retention (CCR) of Pseudomonas putida, we resolve this controversy and show that under NZG conditions, bacteria differentiate into growing and VBNC (viable but not non-culturable) forms, the latter preserving measurable catabolic activity. The proliferating cells attained a steady state, their slow growth balanced by VBNC production. Proteomic analysis revealed upregulated (transporters, stress response, self-degrading enzymes and extracellular polymers) and downregulated (ribosomal, chemotactic and primary biosynthetic enzymes) proteins in the CCR versus batch culture. Based on these profiles, we identified intracellular processes associated with NZG and generated a mathematical model that simulated the observations. We conclude that NZG requires controlled partial self-digestion and deep reconfiguration of the metabolic machinery that results in the biosynthesis of new products and development of broad stress resistance. CCR allows efficient on-line control of NZG including VBNC production. A well-nuanced understanding of NZG is important to understand microbial processes in situ and for optimal design of environmental technologies. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd. |
2014 |
Mandalakis, M; Polymenakou, P N; Tselepides, A; Lampadariou, N Chemosphere, 106 , pp. 28–35, 2014, ISSN: 00456535, (Publisher: Elsevier Ltd). @article{mandalakis_distribution_2014, title = {Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the southern Cretan margin, eastern Mediterranean Sea: A baseline assessment}, author = {M Mandalakis and P N Polymenakou and A Tselepides and N Lampadariou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896546708&doi=10.1016%2fj.chemosphere.2013.12.081&partnerID=40&md5=d9bfaf22c654867d5090f4abfdeee4cd}, doi = {10.1016/j.chemosphere.2013.12.081}, issn = {00456535}, year = {2014}, date = {2014-01-01}, journal = {Chemosphere}, volume = {106}, pages = {28--35}, abstract = {Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (σAH:326-3758ngg-1, dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (σPAH:9-60ngg-1). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg-1), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg-1) and polychlorinated biphenyls (σPCB:38-1182pgg-1) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. © 2014 Elsevier Ltd.}, note = {Publisher: Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (σAH:326-3758ngg-1, dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (σPAH:9-60ngg-1). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg-1), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg-1) and polychlorinated biphenyls (σPCB:38-1182pgg-1) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. © 2014 Elsevier Ltd. |
Sizova, M V; Muller, P A; Stancyk, D; Panikov, N S; Mandalakis, M; Hazen, A; Hohmann, T; Doerfert, S N; Fowle, W; Earl, A M; Nelson, K E; Epstein, S S International Journal of Systematic and Evolutionary Microbiology, 64 (PART 8), pp. 2642–2649, 2014, ISSN: 14665026, (Publisher: Society for General Microbiology). @article{sizova_oribacterium_2014, title = {Oribacterium parvum sp. nov. and Oribacterium asaccharolyticum sp. nov., obligately anaerobic bacteria from the human oral cavity, and emended description of the genus Oribacterium}, author = {M V Sizova and P A Muller and D Stancyk and N S Panikov and M Mandalakis and A Hazen and T Hohmann and S N Doerfert and W Fowle and A M Earl and K E Nelson and S S Epstein}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906069316&doi=10.1099%2fijs.0.060988-0&partnerID=40&md5=5a565dadacfd28e3029f2de32fc9ee84}, doi = {10.1099/ijs.0.060988-0}, issn = {14665026}, year = {2014}, date = {2014-01-01}, journal = {International Journal of Systematic and Evolutionary Microbiology}, volume = {64}, number = {PART 8}, pages = {2642--2649}, abstract = {Three strictly anaerobic, Gram-positive, non-spore-forming, rod-shaped, motile bacteria, designated strains ACB1T, ACB7T and ACB8, were isolated from human subgingival dental plaque. All strains required yeast extract for growth. Strains ACB1T and ACB8 were able to grow on glucose, lactose, maltose, maltodextrin and raffinose; strain ACB7T grew weakly on sucrose only. The growth temperature range was 30-42 °C with optimum growth at 37 °C. Major metabolic fermentation end products of strain ACB1T were acetate and lactate; the only product of strains ACB7T and ACB8 was acetate. Major fatty acids of strain ACB1T were C14: 0, C16: 0, C16: 1ω7c dimethyl aldehyde (DMA) and C18: 1ω7c DMA. Major fatty acids of strain ACB7T were C12: 0, C14: 0, C16: 0, C16: 1ω7c and C16: 1ω7c DMA. The hydrolysate of the peptidoglycan contained meso-diaminopimelic acid, indicating peptidoglycan type A1γ. Genomic DNA G+C content varied from 42 to 43.3 % between strains. According to 16S rRNA gene sequence phylogeny, strains ACB1T, ACB8 and ACB7T formed two separate branches within the genus Oribacterium, with 98.1-98.6 % sequence similarity to the type strain of the type species, Oribacterium sinus. Predicted DNA-DNA hybridization values between strains ACB1T, ACB8, ACB7T and O. sinus F0268 were <70 %. Based on distinct genotypic and phenotypic characteristics, strains ACB1T and ACB8, and strain ACB7T are considered to represent two distinct species of the genus Oribacterium, for which the names Oribacterium parvum sp. nov. and Oribacterium asaccharolyticum sp. nov. are proposed. The type strains are ACB1T (= DSM 24637T = HM-481T = ATCC BAA-2638T) and ACB7T (= DSM 24638T = HM-482T = ATCC BAA-2639T), respectively. © 2014 IUMS.}, note = {Publisher: Society for General Microbiology}, keywords = {}, pubstate = {published}, tppubtype = {article} } Three strictly anaerobic, Gram-positive, non-spore-forming, rod-shaped, motile bacteria, designated strains ACB1T, ACB7T and ACB8, were isolated from human subgingival dental plaque. All strains required yeast extract for growth. Strains ACB1T and ACB8 were able to grow on glucose, lactose, maltose, maltodextrin and raffinose; strain ACB7T grew weakly on sucrose only. The growth temperature range was 30-42 °C with optimum growth at 37 °C. Major metabolic fermentation end products of strain ACB1T were acetate and lactate; the only product of strains ACB7T and ACB8 was acetate. Major fatty acids of strain ACB1T were C14: 0, C16: 0, C16: 1ω7c dimethyl aldehyde (DMA) and C18: 1ω7c DMA. Major fatty acids of strain ACB7T were C12: 0, C14: 0, C16: 0, C16: 1ω7c and C16: 1ω7c DMA. The hydrolysate of the peptidoglycan contained meso-diaminopimelic acid, indicating peptidoglycan type A1γ. Genomic DNA G+C content varied from 42 to 43.3 % between strains. According to 16S rRNA gene sequence phylogeny, strains ACB1T, ACB8 and ACB7T formed two separate branches within the genus Oribacterium, with 98.1-98.6 % sequence similarity to the type strain of the type species, Oribacterium sinus. Predicted DNA-DNA hybridization values between strains ACB1T, ACB8, ACB7T and O. sinus F0268 were <70 %. Based on distinct genotypic and phenotypic characteristics, strains ACB1T and ACB8, and strain ACB7T are considered to represent two distinct species of the genus Oribacterium, for which the names Oribacterium parvum sp. nov. and Oribacterium asaccharolyticum sp. nov. are proposed. The type strains are ACB1T (= DSM 24637T = HM-481T = ATCC BAA-2638T) and ACB7T (= DSM 24638T = HM-482T = ATCC BAA-2639T), respectively. © 2014 IUMS. |
2013 |
Mandalakis, M; Panikov, N; Dai, S; Ray, S; Karger, B L Comparative proteomic analysis reveals mechanistic insights into Pseudomonas putida F1 growth on benzoate and citrate Journal Article AMB Express, 3 , pp. 1–25, 2013, ISSN: 21910855, (Publisher: Springer Verlag). @article{mandalakis_comparative_2013, title = {Comparative proteomic analysis reveals mechanistic insights into Pseudomonas putida F1 growth on benzoate and citrate}, author = {M Mandalakis and N Panikov and S Dai and S Ray and B L Karger}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887177785&doi=10.1186%2f2191-0855-3-64&partnerID=40&md5=3902c4b437456d5b71c20be0c1d45634}, doi = {10.1186/2191-0855-3-64}, issn = {21910855}, year = {2013}, date = {2013-01-01}, journal = {AMB Express}, volume = {3}, pages = {1--25}, abstract = {Pseudomonas species are capable to proliferate under diverse environmental conditions and thus have a significant bioremediation potential. To enhance our understanding of their metabolic versatility, this study explores the changes in the proteome and physiology of Pseudomonas putida F1 resulting from its growth on benzoate, a moderate toxic compound that can be catabolized, and citrate, a carbon source that is assimilated through central metabolic pathways. A series of repetitive batch cultivations were performed to ensure a complete adaptation of the bacteria to each of these contrasting carbon sources. After several growth cycles, cell growth stabilized at the maximum level and exhibited a reproducible growth profile. The specific growth rates measured for benzoate (1.01 ± 0.11 h-1) and citrate (1.11 ± 0.12 h-1) were similar, while a higher yield was observed for benzoate (0.6 and 0.3 g cell mass per g of benzoate and citrate, respectively), reflecting the different degrees of carbon reduction in the two substrates. Comparative proteomic analysis revealed an enrichment of several oxygenases/dehydrogenases in benzoate-grown cells, indicative of the higher carbon reduction of benzoate. Moreover, the upregulation of all 14 proteins implicated in benzoate degradation via the catechol ortho-cleavage pathway was observed, while several stress-response proteins were increased to aid cells to cope with benzoate toxicity. Unexpectedly, citrate posed more challenges than benzoate in the maintenance of pH homeostasis, as indicated by the enhancement of the Na+/H+ antiporter and carbonic anhydrase. The study provides important mechanistic insights into Pseudomonas adaptation to varying carbon sources that are of great relevance to bioremediation efforts. © 2013 Mandalakis et al.}, note = {Publisher: Springer Verlag}, keywords = {}, pubstate = {published}, tppubtype = {article} } Pseudomonas species are capable to proliferate under diverse environmental conditions and thus have a significant bioremediation potential. To enhance our understanding of their metabolic versatility, this study explores the changes in the proteome and physiology of Pseudomonas putida F1 resulting from its growth on benzoate, a moderate toxic compound that can be catabolized, and citrate, a carbon source that is assimilated through central metabolic pathways. A series of repetitive batch cultivations were performed to ensure a complete adaptation of the bacteria to each of these contrasting carbon sources. After several growth cycles, cell growth stabilized at the maximum level and exhibited a reproducible growth profile. The specific growth rates measured for benzoate (1.01 ± 0.11 h-1) and citrate (1.11 ± 0.12 h-1) were similar, while a higher yield was observed for benzoate (0.6 and 0.3 g cell mass per g of benzoate and citrate, respectively), reflecting the different degrees of carbon reduction in the two substrates. Comparative proteomic analysis revealed an enrichment of several oxygenases/dehydrogenases in benzoate-grown cells, indicative of the higher carbon reduction of benzoate. Moreover, the upregulation of all 14 proteins implicated in benzoate degradation via the catechol ortho-cleavage pathway was observed, while several stress-response proteins were increased to aid cells to cope with benzoate toxicity. Unexpectedly, citrate posed more challenges than benzoate in the maintenance of pH homeostasis, as indicated by the enhancement of the Na+/H+ antiporter and carbonic anhydrase. The study provides important mechanistic insights into Pseudomonas adaptation to varying carbon sources that are of great relevance to bioremediation efforts. © 2013 Mandalakis et al. |
Wiegert, C; Mandalakis, M; Knowles, T; Polymenakou, P N; Aeppli, C; Macháčková, J; Holmstrand, H; Evershed, R P; Pancost, R D; Gustafsson, O Carbon and chlorine isotope fractionation during microbial degradation of tetra-and trichloroethene Journal Article Environmental Science and Technology, 47 (12), pp. 6449–6456, 2013, ISSN: 0013936X. @article{wiegert_carbon_2013, title = {Carbon and chlorine isotope fractionation during microbial degradation of tetra-and trichloroethene}, author = {C Wiegert and M Mandalakis and T Knowles and P N Polymenakou and C Aeppli and J Macháčková and H Holmstrand and R P Evershed and R D Pancost and O Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879211180&doi=10.1021%2fes305236y&partnerID=40&md5=03f5f7bbfe402bab4b6a88ddd20e0412}, doi = {10.1021/es305236y}, issn = {0013936X}, year = {2013}, date = {2013-01-01}, journal = {Environmental Science and Technology}, volume = {47}, number = {12}, pages = {6449--6456}, abstract = {Two-dimensional compound-specific isotope analysis (2D-CSIA), combining stable carbon and chlorine isotopes, holds potential for monitoring of natural attenuation of chlorinated ethenes (CEs) in contaminated soil and groundwater. However, interpretation of 2D-CSIA data sets is challenged by a shortage of experimental Cl isotope enrichment factors. Here, isotope enrichments factors for C and Cl (i.e., εC and εCl) were determined for biodegradation of tetrachloroethene (PCE) and trichloroethene (TCE) using microbial enrichment cultures from a heavily CE-contaminated aquifer. The obtained values were εC = -5.6 ± 0.7‰ (95% CI) and εCl = -2.0 ± 0.5‰ for PCE degradation and εC = -8.8 ± 0.2‰ and εCl = -3.5 ± 0.5‰ for TCE degradation. Combining the values for both εC and εCl yielded mechanism-diagnostic εCl/εC ratios of 0.35 ± 0.11 and 0.37 ± 0.11 for the degradation of PCE and TCE, respectively. Application of the obtained εC and εCl values to a previously investigated field site gave similar estimates for the fraction of degraded contaminant as in the previous study, but with a reduced uncertainty in assessment of the natural attenuation. Furthermore, 16S rRNA gene clone library analyses were performed on three samples from the PCE degradation experiments. A species closely related to Desulfitobacterium aromaticivorans UKTL dominated the reductive dechlorination process. This study contributes to the development of 2D-CSIA as a tool for evaluating remediation strategies of CEs at contaminated sites. © 2013 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional compound-specific isotope analysis (2D-CSIA), combining stable carbon and chlorine isotopes, holds potential for monitoring of natural attenuation of chlorinated ethenes (CEs) in contaminated soil and groundwater. However, interpretation of 2D-CSIA data sets is challenged by a shortage of experimental Cl isotope enrichment factors. Here, isotope enrichments factors for C and Cl (i.e., εC and εCl) were determined for biodegradation of tetrachloroethene (PCE) and trichloroethene (TCE) using microbial enrichment cultures from a heavily CE-contaminated aquifer. The obtained values were εC = -5.6 ± 0.7‰ (95% CI) and εCl = -2.0 ± 0.5‰ for PCE degradation and εC = -8.8 ± 0.2‰ and εCl = -3.5 ± 0.5‰ for TCE degradation. Combining the values for both εC and εCl yielded mechanism-diagnostic εCl/εC ratios of 0.35 ± 0.11 and 0.37 ± 0.11 for the degradation of PCE and TCE, respectively. Application of the obtained εC and εCl values to a previously investigated field site gave similar estimates for the fraction of degraded contaminant as in the previous study, but with a reduced uncertainty in assessment of the natural attenuation. Furthermore, 16S rRNA gene clone library analyses were performed on three samples from the PCE degradation experiments. A species closely related to Desulfitobacterium aromaticivorans UKTL dominated the reductive dechlorination process. This study contributes to the development of 2D-CSIA as a tool for evaluating remediation strategies of CEs at contaminated sites. © 2013 American Chemical Society. |
Oulas, Anastasis; Polymenakou, Paraskevi N; Mandalakis, Manolis; Nomikou, Paraskevi; Carey, Steven; Christakis, Christos; Kotoulas, Georgios; Magoulas, Antonios; Tripp, James H; Espino, David Paez A; Ivanova, Natalia N; Kyrpides, Nikos C Metagenomics of microbial communities inhabiting the Kolumbo volcano shallow-sea hydrothermal vent field and Santorini (caldera) Inproceedings 2013, (Publication Title: The 8th conference of the Hellenic Society for Computational Biology and Bioinformatics - HSCBB13). @inproceedings{oulas_metagenomics_2013, title = {Metagenomics of microbial communities inhabiting the Kolumbo volcano shallow-sea hydrothermal vent field and Santorini (caldera)}, author = {Anastasis Oulas and Paraskevi N Polymenakou and Manolis Mandalakis and Paraskevi Nomikou and Steven Carey and Christos Christakis and Georgios Kotoulas and Antonios Magoulas and James H Tripp and David Paez A Espino and Natalia N Ivanova and Nikos C Kyrpides}, year = {2013}, date = {2013-01-01}, note = {Publication Title: The 8th conference of the Hellenic Society for Computational Biology and Bioinformatics - HSCBB13}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Polymenakou, P N; Nomikou, P; Mandalakis, M; Kilias, S P; Christakis, C; Kyrpides, N; Ivanova, N; Oulas, A; Dailianis, Thanos; Carey, S; Kotoulas, G; Magoulas, A; Papanikolaou, D Microbiological exploration of a unique CO2-rich shallow submarine hydrothermal vent field (Kolumbo, Santorini island, Aegean Sea) Inproceedings Heraklion Crete, Greece, 2013, (Publication Title: Mediterranean Marine Biodiversity Conference Type: Oral Presentation). @inproceedings{polymenakou_microbiological_2013, title = {Microbiological exploration of a unique CO2-rich shallow submarine hydrothermal vent field (Kolumbo, Santorini island, Aegean Sea)}, author = {P N Polymenakou and P Nomikou and M Mandalakis and S P Kilias and C Christakis and N Kyrpides and N Ivanova and A Oulas and Thanos Dailianis and S Carey and G Kotoulas and A Magoulas and D Papanikolaou}, year = {2013}, date = {2013-01-01}, address = {Heraklion Crete, Greece}, note = {Publication Title: Mediterranean Marine Biodiversity Conference Type: Oral Presentation}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Sizova, M V; Muller, P; Panikov, N; Mandalakis, M; Hohmann, T; Hazen, A; Fowle, W; Prozorov, T; Bazylinski, D A; Epstein, S S Stomatobaculum longum gen. nov., sp. nov., an obligately anaerobic bacterium from the human oral cavity Journal Article International Journal of Systematic and Evolutionary Microbiology, 63 (PART4), pp. 1450–1456, 2013, ISSN: 14665026. @article{sizova_stomatobaculum_2013, title = {Stomatobaculum longum gen. nov., sp. nov., an obligately anaerobic bacterium from the human oral cavity}, author = {M V Sizova and P Muller and N Panikov and M Mandalakis and T Hohmann and A Hazen and W Fowle and T Prozorov and D A Bazylinski and S S Epstein}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876076178&doi=10.1099%2fijs.0.042812-0&partnerID=40&md5=19c37c8161298098fdad4d6d9b78c9e5}, doi = {10.1099/ijs.0.042812-0}, issn = {14665026}, year = {2013}, date = {2013-01-01}, journal = {International Journal of Systematic and Evolutionary Microbiology}, volume = {63}, number = {PART4}, pages = {1450--1456}, abstract = {A strictly anaerobic Gram-stain-variable but positive by structure, non-spore-forming bacterium designated Lachnospiraceae bacterium ACC2 strain DSM 24645T was isolated from human subgingival dental plaque. Bacterial cells were 4-40 μm long non-motile rods, often swollen and forming curved filaments up to 200 μm. Cells contained intracellular, poorly crystalline, nanometre-sized iron- and sulfur-rich particles. The micro-organism was able to grow on yeast extract, trypticase peptone, milk, some sugars and organic acids. The major metabolic end-products of glucose fermentation were butyrate, lactate, isovalerate and acetate. The growth temperature and pH ranges were 30-42 °C and 4.9-7.5, respectively. Major fatty acids were C14:0, C14:0 DMA (dimethyl aldehyde), C16:0, C16:1 ω7c DMA. The whole-cell hydrolysate contained meso-diaminopimelic acid, indicating peptidoglycan type A1γ. The DNA G+C content was calculated to be 55.05 mol% from the whole-genome sequence and 55.3 mol% as determined by HPLC. There were no predicted genes responsible for biosynthesis of respiratory lipoquinones, mycolic acids and lipopolysaccharides. Genes associated with synthesis of teichoic and lipoteichoic acids, diaminopimelic acid, polar lipids and polyamines were present. According to the 16S rRNA gene sequence phylogeny, strain DSM 24645T formed, together with several uncultured oral clones, a separate branch within the family Lachnospiraceae, with the highest sequence similarity to the type strain of Moryella indoligenes at 94.2%. Based on distinct phenotypic and genotypic characteristics, we suggest that strain DSM 24645T represents a novel species in a new genus, for which the name Stomatobaculum longum gen. nov., sp. nov. is proposed. The type strain of Stomatobaculum longum is DSM 24645T (=HM-480T; deposited in BEI Resources, an NIH collection managed by the ATCC). © 2013 IUMS Printed in Great Britain.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A strictly anaerobic Gram-stain-variable but positive by structure, non-spore-forming bacterium designated Lachnospiraceae bacterium ACC2 strain DSM 24645T was isolated from human subgingival dental plaque. Bacterial cells were 4-40 μm long non-motile rods, often swollen and forming curved filaments up to 200 μm. Cells contained intracellular, poorly crystalline, nanometre-sized iron- and sulfur-rich particles. The micro-organism was able to grow on yeast extract, trypticase peptone, milk, some sugars and organic acids. The major metabolic end-products of glucose fermentation were butyrate, lactate, isovalerate and acetate. The growth temperature and pH ranges were 30-42 °C and 4.9-7.5, respectively. Major fatty acids were C14:0, C14:0 DMA (dimethyl aldehyde), C16:0, C16:1 ω7c DMA. The whole-cell hydrolysate contained meso-diaminopimelic acid, indicating peptidoglycan type A1γ. The DNA G+C content was calculated to be 55.05 mol% from the whole-genome sequence and 55.3 mol% as determined by HPLC. There were no predicted genes responsible for biosynthesis of respiratory lipoquinones, mycolic acids and lipopolysaccharides. Genes associated with synthesis of teichoic and lipoteichoic acids, diaminopimelic acid, polar lipids and polyamines were present. According to the 16S rRNA gene sequence phylogeny, strain DSM 24645T formed, together with several uncultured oral clones, a separate branch within the family Lachnospiraceae, with the highest sequence similarity to the type strain of Moryella indoligenes at 94.2%. Based on distinct phenotypic and genotypic characteristics, we suggest that strain DSM 24645T represents a novel species in a new genus, for which the name Stomatobaculum longum gen. nov., sp. nov. is proposed. The type strain of Stomatobaculum longum is DSM 24645T (=HM-480T; deposited in BEI Resources, an NIH collection managed by the ATCC). © 2013 IUMS Printed in Great Britain. |
Polymenakou, P N; Mandalakis, M Aerobiologia, 29 (3), pp. 429–441, 2013, ISSN: 03935965. @article{polymenakou_assessing_2013, title = {Assessing the short-term variability of bacterial composition in background aerosols of the Eastern Mediterranean during a rapid change of meteorological conditions}, author = {P N Polymenakou and M Mandalakis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880310891&doi=10.1007%2fs10453-013-9295-1&partnerID=40&md5=ef667ffa44cfdff0d4e71cddb8e8b969}, doi = {10.1007/s10453-013-9295-1}, issn = {03935965}, year = {2013}, date = {2013-01-01}, journal = {Aerobiologia}, volume = {29}, number = {3}, pages = {429--441}, abstract = {This study used a PCR-based molecular identification technique to examine bacterial assemblage composition in background aerosols of the eastern Mediterranean Sea during a rapid change of meteorological conditions. 16S rDNA fragments of 166 clones were identified and were affiliated with six bacterial phyla (Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Spirochetes, and Fusobacteria), plant-related sequences, and other uncultivated bacterial groups. The analyzed clones were closely related to sequences previously characterized from diverse sources including soil, plants, marine water and sediment, human skin, activated sludge, house dust, indoor air, gut microbiota, and food. Plant- and human-associated sequences accounted for the largest fraction of the identified clones. Spore-forming Firmicutes showed a considerable increase when air mass origin changed from north to south implying that south winds favored bacterial spores transportation from the inland of Crete or North Africa. However, no conclusive trends were revealed for other groups of microorganisms. The influence of air mass origin was further investigated for marine- and terrestrial-associated sequences. A higher number of marine-associated sequences were identified when south winds crossed the inland of Crete, while the opposite was observed when north winds passed over the Aegean Sea. This discrepancy could be partly explained by the fact that the north winds were blowing at very low speed which constrained the formation of sea-spray aerosols and the ejection of marine microbes from sea surface to the atmosphere. Overall, the interpretation of bacterial assemblage composition in relation to the meteorological conditions was proved to be a complicated task which is in line with previous studies. © 2013 Springer Science+Business Media Dordrecht.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This study used a PCR-based molecular identification technique to examine bacterial assemblage composition in background aerosols of the eastern Mediterranean Sea during a rapid change of meteorological conditions. 16S rDNA fragments of 166 clones were identified and were affiliated with six bacterial phyla (Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Spirochetes, and Fusobacteria), plant-related sequences, and other uncultivated bacterial groups. The analyzed clones were closely related to sequences previously characterized from diverse sources including soil, plants, marine water and sediment, human skin, activated sludge, house dust, indoor air, gut microbiota, and food. Plant- and human-associated sequences accounted for the largest fraction of the identified clones. Spore-forming Firmicutes showed a considerable increase when air mass origin changed from north to south implying that south winds favored bacterial spores transportation from the inland of Crete or North Africa. However, no conclusive trends were revealed for other groups of microorganisms. The influence of air mass origin was further investigated for marine- and terrestrial-associated sequences. A higher number of marine-associated sequences were identified when south winds crossed the inland of Crete, while the opposite was observed when north winds passed over the Aegean Sea. This discrepancy could be partly explained by the fact that the north winds were blowing at very low speed which constrained the formation of sea-spray aerosols and the ejection of marine microbes from sea surface to the atmosphere. Overall, the interpretation of bacterial assemblage composition in relation to the meteorological conditions was proved to be a complicated task which is in line with previous studies. © 2013 Springer Science+Business Media Dordrecht. |
2011 |
Mandalakis, M; Apostolaki, M; Tziaras, T; Polymenakou, P; Stephanou, E G Free and combined amino acids in marine background atmospheric aerosols over the Eastern Mediterranean Journal Article Atmospheric Environment, 45 (4), pp. 1003–1009, 2011, ISSN: 13522310. @article{mandalakis_free_2011, title = {Free and combined amino acids in marine background atmospheric aerosols over the Eastern Mediterranean}, author = {M Mandalakis and M Apostolaki and T Tziaras and P Polymenakou and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650970210&doi=10.1016%2fj.atmosenv.2010.10.046&partnerID=40&md5=2b9f84c32b126f829caf5b42b32eab66}, doi = {10.1016/j.atmosenv.2010.10.046}, issn = {13522310}, year = {2011}, date = {2011-01-01}, journal = {Atmospheric Environment}, volume = {45}, number = {4}, pages = {1003--1009}, abstract = {During a six-week intensive field campaign at a background marine site of the Eastern Mediterranean, consecutive 24-h air samples were collected and analyzed for combined (CAA) and free amino acids (FAA), as well as for key chemical characteristics of aerosols. The total concentration of CAA (719 ± 326 pmol m-3) was on average four times higher than that of FAA (172 ± 147 pmol m-3), while glycine was the most abundant compound detected in both FAA and CAA. Back-trajectory analysis demonstrated that the geographical origin of the air masses did not have a significant influence on the atmospheric levels of amino acids. Wind speed was found to be the most important meteorological factor and it exhibited a negative correlation with both FAA and CAA. Moreover, FAA and CAA concentrations showed a more pronounced correlation with water-soluble organic carbon (WSOC) than elemental carbon. On average, FAA and CAA accounted for 0.3 ± 0.2% and 1.8 ± 0.8% of WSOC, respectively. The levels of anionic surfactants determined as methylene blue active substances did not show any positive correlation with CAA, while the corresponding correlation with FAA was only of marginal significance. The total protein concentration measured by NanoOrange assay was six times higher compared to that measured through CAA. It is suggested that the results from the application of commercially available protein quantitation kits should always be considered with caution, as these are more prone to matrix-related interferences. © 2010 Elsevier Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } During a six-week intensive field campaign at a background marine site of the Eastern Mediterranean, consecutive 24-h air samples were collected and analyzed for combined (CAA) and free amino acids (FAA), as well as for key chemical characteristics of aerosols. The total concentration of CAA (719 ± 326 pmol m-3) was on average four times higher than that of FAA (172 ± 147 pmol m-3), while glycine was the most abundant compound detected in both FAA and CAA. Back-trajectory analysis demonstrated that the geographical origin of the air masses did not have a significant influence on the atmospheric levels of amino acids. Wind speed was found to be the most important meteorological factor and it exhibited a negative correlation with both FAA and CAA. Moreover, FAA and CAA concentrations showed a more pronounced correlation with water-soluble organic carbon (WSOC) than elemental carbon. On average, FAA and CAA accounted for 0.3 ± 0.2% and 1.8 ± 0.8% of WSOC, respectively. The levels of anionic surfactants determined as methylene blue active substances did not show any positive correlation with CAA, while the corresponding correlation with FAA was only of marginal significance. The total protein concentration measured by NanoOrange assay was six times higher compared to that measured through CAA. It is suggested that the results from the application of commercially available protein quantitation kits should always be considered with caution, as these are more prone to matrix-related interferences. © 2010 Elsevier Ltd. |
2010 |
Kouridaki, I; Polymenakou, P N; Tselepides, A; Mandalakis, M; Jr., Smith K L Phylogenetic diversity of sediment bacteria from the deep Northeastern Pacific Ocean: A comparison with the deep Eastern Mediterranean Sea Journal Article International Microbiology, 13 (3), pp. 143–150, 2010, ISSN: 11396709, (Publisher: Sociedad Espanola de Microbiologia). @article{kouridaki_phylogenetic_2010, title = {Phylogenetic diversity of sediment bacteria from the deep Northeastern Pacific Ocean: A comparison with the deep Eastern Mediterranean Sea}, author = {I Kouridaki and P N Polymenakou and A Tselepides and M Mandalakis and K L Smith Jr.}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79251591617&doi=10.2436%2f20.1501.01.119&partnerID=40&md5=2af215d627ad9a23e6fb4253c3cce940}, doi = {10.2436/20.1501.01.119}, issn = {11396709}, year = {2010}, date = {2010-01-01}, journal = {International Microbiology}, volume = {13}, number = {3}, pages = {143--150}, abstract = {The variability of bacterial community composition and diversity was studied by comparative analysis of five 16S rRNA gene clone libraries from deep-sea sediments (water column depth: 4000 m) of the Northeastern Pacific Ocean and Eastern Mediterranean Sea. This is the first comparison of the bacterial communities living in these deep-sea ecosystems. The estimated chlorophyll a, organic carbon, and C/N ratio provided evidence of significant differences in the trophic state of the sediments between the Northeastern Pacific Ocean and the much warmer Eastern Mediterranean Sea. A diverse range of 16S rRNA gene phylotypes was found in the sediments of both regions. These were represented by 11 different taxonomic groups, with Gammaproteobacteria predominating in the Northeastern Pacific Ocean sediments and Acidobacteria in the Eastern Mediterranean microbial community. In addition, several 16S rRNA gene phylotypes only distantly related to any of the previously identified sequences (non-affiliated rRNA genes) represented a significant fraction of the total sequences. The potential diversity at the two sites differs but remains largely unexplored and remains of continuing scientific interest.}, note = {Publisher: Sociedad Espanola de Microbiologia}, keywords = {}, pubstate = {published}, tppubtype = {article} } The variability of bacterial community composition and diversity was studied by comparative analysis of five 16S rRNA gene clone libraries from deep-sea sediments (water column depth: 4000 m) of the Northeastern Pacific Ocean and Eastern Mediterranean Sea. This is the first comparison of the bacterial communities living in these deep-sea ecosystems. The estimated chlorophyll a, organic carbon, and C/N ratio provided evidence of significant differences in the trophic state of the sediments between the Northeastern Pacific Ocean and the much warmer Eastern Mediterranean Sea. A diverse range of 16S rRNA gene phylotypes was found in the sediments of both regions. These were represented by 11 different taxonomic groups, with Gammaproteobacteria predominating in the Northeastern Pacific Ocean sediments and Acidobacteria in the Eastern Mediterranean microbial community. In addition, several 16S rRNA gene phylotypes only distantly related to any of the previously identified sequences (non-affiliated rRNA genes) represented a significant fraction of the total sequences. The potential diversity at the two sites differs but remains largely unexplored and remains of continuing scientific interest. |
Harrad, S; Wit, De C A; Abdallah, M A -E; Bergh, C; Björklund, J A; Covaci, A; Darnerud, P O; Boer, De J; Diamond, M; Huber, S; Leonards, P; Mandalakis, M; Östman, C; Haug, L S; Thomsen, C; Webster, T F Environmental Science and Technology, 44 (9), pp. 3221–3231, 2010, ISSN: 0013936X. @article{harrad_indoor_2010, title = {Indoor contamination with hexabromocyclododecanes, polybrominated diphenyl ethers, and perfluoroalkyl compounds: An important exposure pathway for people?}, author = {S Harrad and C A De Wit and M A -E Abdallah and C Bergh and J A Björklund and A Covaci and P O Darnerud and J De Boer and M Diamond and S Huber and P Leonards and M Mandalakis and C Östman and L S Haug and C Thomsen and T F Webster}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951838242&doi=10.1021%2fes903476t&partnerID=40&md5=13253de877e4d2349ff96cc5f51075f2}, doi = {10.1021/es903476t}, issn = {0013936X}, year = {2010}, date = {2010-01-01}, journal = {Environmental Science and Technology}, volume = {44}, number = {9}, pages = {3221--3231}, abstract = {This review underlines the importance of indoor contamination as a pathway of human exposure to hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), and perfluoroalkyl compounds (PFCs). There is ample evidence of substantial contamination of indoor dust with these chemicals and that their concentrations in indoor air exceed substantially those outdoors. Studies examining the relationship between body burden and exposure via indoor dust are inconsistent; while some indicate a link between body burdens and PBDE and HBCD exposure via dust ingestion, others find no correlation. Likewise, while concentrations in indoor dust and human tissues are both highly skewed, this does not necessarily imply causality. Evidence suggests exposure via dust ingestion is higher for toddlers than adults. Research priorities include identifying means of reducing indoor concentrations and indoor monitoring methods that provide the most "biologically-relevant" measures of exposure as well as monitoring a wider range of microenvironment categories. Other gaps include studies to improve understanding of the following: emission rates and mechanisms via which these contaminants migrate from products into indoor air and dust; relationships between indoor exposures and human body burdens; relevant physicochemical properties; the gastrointestinal uptake by humans of these chemicals from indoor dust; and human dust ingestion rates. © 2010 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This review underlines the importance of indoor contamination as a pathway of human exposure to hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), and perfluoroalkyl compounds (PFCs). There is ample evidence of substantial contamination of indoor dust with these chemicals and that their concentrations in indoor air exceed substantially those outdoors. Studies examining the relationship between body burden and exposure via indoor dust are inconsistent; while some indicate a link between body burdens and PBDE and HBCD exposure via dust ingestion, others find no correlation. Likewise, while concentrations in indoor dust and human tissues are both highly skewed, this does not necessarily imply causality. Evidence suggests exposure via dust ingestion is higher for toddlers than adults. Research priorities include identifying means of reducing indoor concentrations and indoor monitoring methods that provide the most "biologically-relevant" measures of exposure as well as monitoring a wider range of microenvironment categories. Other gaps include studies to improve understanding of the following: emission rates and mechanisms via which these contaminants migrate from products into indoor air and dust; relationships between indoor exposures and human body burdens; relevant physicochemical properties; the gastrointestinal uptake by humans of these chemicals from indoor dust; and human dust ingestion rates. © 2010 American Chemical Society. |
Mandalakis, M; Apostolaki, M; Stephanou, E G Trace analysis of free and combined amino acids in atmospheric aerosols by gas chromatography-mass spectrometry Journal Article Journal of Chromatography A, 1217 (1), pp. 143–150, 2010, ISSN: 00219673. @article{mandalakis_trace_2010, title = {Trace analysis of free and combined amino acids in atmospheric aerosols by gas chromatography-mass spectrometry}, author = {M Mandalakis and M Apostolaki and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049084756&doi=10.1016%2fj.chroma.2009.11.021&partnerID=40&md5=7d80d9025c5ad2bd86ed78301c7f59a7}, doi = {10.1016/j.chroma.2009.11.021}, issn = {00219673}, year = {2010}, date = {2010-01-01}, journal = {Journal of Chromatography A}, volume = {1217}, number = {1}, pages = {143--150}, abstract = {The analysis of amino acids by gas chromatography mass spectrometry (GC-MS) after their derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide was investigated as an alternative approach for the determination of free (FAA) and combined amino acids (CAA) in aerosols. This technique showed excellent linearity with r2 values ranging from 0.9029 to 0.9995 and instrumental limits of detection ranging from 0.3 to 46 pg for the different amino acids. The quality of water used for sample extraction was found to be of utmost importance for achieving low blank levels of FAA and CAA. The addition of isopropanol during the extraction of aerosols was also shown to minimize the coextraction of inorganic salts that interfered with the analysis of FAA, Moreover, the ascorbic acid was found to be the most effective reagent for preventing the oxidative destruction of CAA during the hydrolysis process. By the analysis of spiked aerosol samples, the average recoveries determined for FAA and CAA were higher than 60% and the associated relative standard deviation was lower than 10% for the majority of amino acids. The application of the adopted method in background aerosols of the eastern Mediterranean enabled the unambiguous identification and quantification of 20 amino acids. The total concentration of FAA and CAA in aerosols ranged from 13 to 34 ng m-3 and from 29 to 79 ng m-3, respectively. The GC-MS based method is proposed to overcome several analytical difficulties usually encountered with the conventional HPLC-fluoresence technique. © 2009 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The analysis of amino acids by gas chromatography mass spectrometry (GC-MS) after their derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide was investigated as an alternative approach for the determination of free (FAA) and combined amino acids (CAA) in aerosols. This technique showed excellent linearity with r2 values ranging from 0.9029 to 0.9995 and instrumental limits of detection ranging from 0.3 to 46 pg for the different amino acids. The quality of water used for sample extraction was found to be of utmost importance for achieving low blank levels of FAA and CAA. The addition of isopropanol during the extraction of aerosols was also shown to minimize the coextraction of inorganic salts that interfered with the analysis of FAA, Moreover, the ascorbic acid was found to be the most effective reagent for preventing the oxidative destruction of CAA during the hydrolysis process. By the analysis of spiked aerosol samples, the average recoveries determined for FAA and CAA were higher than 60% and the associated relative standard deviation was lower than 10% for the majority of amino acids. The application of the adopted method in background aerosols of the eastern Mediterranean enabled the unambiguous identification and quantification of 20 amino acids. The total concentration of FAA and CAA in aerosols ranged from 13 to 34 ng m-3 and from 29 to 79 ng m-3, respectively. The GC-MS based method is proposed to overcome several analytical difficulties usually encountered with the conventional HPLC-fluoresence technique. © 2009 Elsevier B.V. All rights reserved. |
Holmstrand, H; Zencak, Z; Mandalakis, M; Andersson, P; Gustafsson, Ö Chlorine isotope evidence for the anthropogenic origin of tris-(4-chlorophenyl)methane Journal Article Applied Geochemistry, 25 (9), pp. 1301–1306, 2010, ISSN: 08832927. @article{holmstrand_chlorine_2010, title = {Chlorine isotope evidence for the anthropogenic origin of tris-(4-chlorophenyl)methane}, author = {H Holmstrand and Z Zencak and M Mandalakis and P Andersson and Ö Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955664186&doi=10.1016%2fj.apgeochem.2010.06.001&partnerID=40&md5=cae61131de32477986d1c0ad156179d9}, doi = {10.1016/j.apgeochem.2010.06.001}, issn = {08832927}, year = {2010}, date = {2010-01-01}, journal = {Applied Geochemistry}, volume = {25}, number = {9}, pages = {1301--1306}, abstract = {Compound-specific Cl-isotope analysis was performed on the persistent and bioaccumulating compound tris-(4-chlorophenyl)methane (4,4',4″-TCPMe, referred to as TCPMe in this study) to elucidate whether its main source is natural or anthropogenic. Blubber from the Baltic grey seal (Halichoerus grypus) was extracted by continuous acetonitrile partitioning, and the TCPMe was isolated from the extract by preparative-capillary gas chromatography. Chlorine isotope analysis was subsequently performed by sealed-tube combustion in conjunction with thermal-ionization mass spectrometry (TIMS). The δ37Cl of TCPMe was -3.5±0.5‰, similar to the previously reported δ37Cl of technical grade p,p'-DDT (referred to as DDT in this study). The data is not consistent with a putative marine natural source of TCPMe, as enzymatic (biotic) production is reported to give values of δ37Cl<-10‰. The δ37Cl-TCPMe data thus supports the hypothesis that TCPMe is produced as a byproduct during DDT synthesis and is released to the environment through the same pathways as DDT. It is also consistent with tris-(4-chlorophenyl)methanol as the primary biotransformation product of TCPMe. © 2010 Elsevier Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Compound-specific Cl-isotope analysis was performed on the persistent and bioaccumulating compound tris-(4-chlorophenyl)methane (4,4',4″-TCPMe, referred to as TCPMe in this study) to elucidate whether its main source is natural or anthropogenic. Blubber from the Baltic grey seal (Halichoerus grypus) was extracted by continuous acetonitrile partitioning, and the TCPMe was isolated from the extract by preparative-capillary gas chromatography. Chlorine isotope analysis was subsequently performed by sealed-tube combustion in conjunction with thermal-ionization mass spectrometry (TIMS). The δ37Cl of TCPMe was -3.5±0.5‰, similar to the previously reported δ37Cl of technical grade p,p'-DDT (referred to as DDT in this study). The data is not consistent with a putative marine natural source of TCPMe, as enzymatic (biotic) production is reported to give values of δ37Cl<-10‰. The δ37Cl-TCPMe data thus supports the hypothesis that TCPMe is produced as a byproduct during DDT synthesis and is released to the environment through the same pathways as DDT. It is also consistent with tris-(4-chlorophenyl)methanol as the primary biotransformation product of TCPMe. © 2010 Elsevier Ltd. |
Polymenakou, P N; Kyrpides, N; Mavrommatis, K; Ivanova, N; Mandalakis, M; Alexandri, S Metagenomic exploration of the newly discovered hydrothermal vent sites in the submarine Kolumbo volcano (Santorini, Greece): Preliminary results Inproceedings Noesis, Thessaloniki, Greece, 2010, (Publication Title: 3rd National Mikrobiokosmos Conference Type: Oral Presentation). @inproceedings{polymenakou_metagenomic_2010, title = {Metagenomic exploration of the newly discovered hydrothermal vent sites in the submarine Kolumbo volcano (Santorini, Greece): Preliminary results}, author = {P N Polymenakou and N Kyrpides and K Mavrommatis and N Ivanova and M Mandalakis and S Alexandri}, year = {2010}, date = {2010-01-01}, address = {Noesis, Thessaloniki, Greece}, note = {Publication Title: 3rd National Mikrobiokosmos Conference Type: Oral Presentation}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Polymenakou, P N; Mandalakis, M; Wijker, R; Hofstetter, T Microbial degradation of dinitrotoluenes (2,4- and 2,6-DNTs) by mixed soil cultures for the determination of isotopic fractionation Inproceedings Noesis, Thessaloniki, Greece, 2010, (Publication Title: 3rd National Mikrobiokosmos Conference Type: poster). @inproceedings{polymenakou_microbial_2010, title = {Microbial degradation of dinitrotoluenes (2,4- and 2,6-DNTs) by mixed soil cultures for the determination of isotopic fractionation}, author = {P N Polymenakou and M Mandalakis and R Wijker and T Hofstetter}, year = {2010}, date = {2010-01-01}, address = {Noesis, Thessaloniki, Greece}, note = {Publication Title: 3rd National Mikrobiokosmos Conference Type: poster}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Tziaras, T; Spyros, A; Mandalakis, M; Apostolaki, M; Stephanou, E G Water soluble organic compounds over the eastern Mediterranean: Study of their occurrence and sources Inproceedings Geophysical Research Abstracts, pp. EGU2010–15342, 2010. @inproceedings{tziaras_water_2010, title = {Water soluble organic compounds over the eastern Mediterranean: Study of their occurrence and sources}, author = {T Tziaras and A Spyros and M Mandalakis and M Apostolaki and E G Stephanou}, year = {2010}, date = {2010-01-01}, booktitle = {Geophysical Research Abstracts}, volume = {12}, pages = {EGU2010--15342}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2009 |
Polymenakou, P N; Lampadariou, N; Mandalakis, M; Tselepides, A Phylogenetic diversity of sediment bacteria from the southern Cretan margin, Eastern Mediterranean Sea Journal Article Systematic and Applied Microbiology, 32 (1), pp. 17–26, 2009, ISSN: 07232020. @article{polymenakou_phylogenetic_2009, title = {Phylogenetic diversity of sediment bacteria from the southern Cretan margin, Eastern Mediterranean Sea}, author = {P N Polymenakou and N Lampadariou and M Mandalakis and A Tselepides}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149484940&doi=10.1016%2fj.syapm.2008.09.006&partnerID=40&md5=17b34fc20d7f492b43bc1cb3ba96588f}, doi = {10.1016/j.syapm.2008.09.006}, issn = {07232020}, year = {2009}, date = {2009-01-01}, journal = {Systematic and Applied Microbiology}, volume = {32}, number = {1}, pages = {17--26}, abstract = {This study is the first culture-independent report on the regional variability of bacterial diversity in oxic sediments from the unexplored southern Cretan margin (SCM). Three main deep basins (water column depths: 2670-3603 m), located at the mouth of two submarine canyons (Samaria Gorge and Paximades Channel) and an adjacent slope system, as well as two shallow upper-slope stations (water column depths: 215 and 520 m), were sampled. A total of 454 clones were sequenced and the bacterial richness, estimated through five clone libraries using rarefaction analysis, ranged from 71 to 296 unique phylotypes. The average sequence identity of the retrieved Cretan margin sequences compared to the textgreater1,000,000 known rRNA sequences was only 93.5%. A diverse range of prokaryotes was found in the sediments, which were represented by 15 different taxonomic groups at the phylum level. The phylogenetic analysis revealed that these new sequences grouped with the phyla Acidobacteria, Planctomycetes, Actinobacteria, Gamma-, Alpha- and Delta-proteobacteria. Only a few bacterial clones were affiliated with Chloroflexi, Bacteroidetes, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Nitrospirae, Beta-proteobacteria, Lentisphaerae and Dictyoglomi. A large fraction of the retrieved sequences (12%) did not fall into any taxonomic division previously characterized by molecular criteria, whereas four novel division-level lineages, termed candidate division SCMs, were identified. Bacterial community composition demonstrated significant differences in comparison to previous phylogenetic studies. This divergence was mainly triggered by the dominance of Acidobacteria and Actinobacteria and reflected a bacterial community different from that currently known for oxic and pristine marine sediments. © 2008 Elsevier GmbH. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This study is the first culture-independent report on the regional variability of bacterial diversity in oxic sediments from the unexplored southern Cretan margin (SCM). Three main deep basins (water column depths: 2670-3603 m), located at the mouth of two submarine canyons (Samaria Gorge and Paximades Channel) and an adjacent slope system, as well as two shallow upper-slope stations (water column depths: 215 and 520 m), were sampled. A total of 454 clones were sequenced and the bacterial richness, estimated through five clone libraries using rarefaction analysis, ranged from 71 to 296 unique phylotypes. The average sequence identity of the retrieved Cretan margin sequences compared to the textgreater1,000,000 known rRNA sequences was only 93.5%. A diverse range of prokaryotes was found in the sediments, which were represented by 15 different taxonomic groups at the phylum level. The phylogenetic analysis revealed that these new sequences grouped with the phyla Acidobacteria, Planctomycetes, Actinobacteria, Gamma-, Alpha- and Delta-proteobacteria. Only a few bacterial clones were affiliated with Chloroflexi, Bacteroidetes, Firmicutes, Gemmatimonadetes, Verrucomicrobia, Nitrospirae, Beta-proteobacteria, Lentisphaerae and Dictyoglomi. A large fraction of the retrieved sequences (12%) did not fall into any taxonomic division previously characterized by molecular criteria, whereas four novel division-level lineages, termed candidate division SCMs, were identified. Bacterial community composition demonstrated significant differences in comparison to previous phylogenetic studies. This divergence was mainly triggered by the dominance of Acidobacteria and Actinobacteria and reflected a bacterial community different from that currently known for oxic and pristine marine sediments. © 2008 Elsevier GmbH. All rights reserved. |
Mandalakis, M; Besis, A; Stephanou, E G Particle-size distribution and gas/particle partitioning of atmospheric polybrominated diphenyl ethers in urban areas of Greece Journal Article Environmental Pollution, 157 (4), pp. 1227–1233, 2009, ISSN: 02697491. @article{mandalakis_particle-size_2009, title = {Particle-size distribution and gas/particle partitioning of atmospheric polybrominated diphenyl ethers in urban areas of Greece}, author = {M Mandalakis and A Besis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-60949094059&doi=10.1016%2fj.envpol.2008.12.010&partnerID=40&md5=48f607e7fc48bf8949aa8137b5690d8f}, doi = {10.1016/j.envpol.2008.12.010}, issn = {02697491}, year = {2009}, date = {2009-01-01}, journal = {Environmental Pollution}, volume = {157}, number = {4}, pages = {1227--1233}, abstract = {Ambient concentrations, gas/particle partitioning and particle-size distribution of polybrominated diphenyl ethers (PBDEs) were investigated in two urban areas (Athens and Heraklion) of Greece. Atmospheric (gas + particle) concentrations of ∑PBDE varied from 21 to 30 pg m -3 in the center of Athens and from 4 to 44 pg m -3 in the suburbs of Heraklion. A predominance of particulate PBDEs was observed in Athens (71-76% in particles), whereas the opposite was evident in Heraklion (69-92% in gas phase). In both urban areas, PBDE particle-size distribution featured a distinct enrichment in smaller particles. A similar trend was also observed in aerosols of a background marine site. For all sampling sites, more than 46% of ∑PBDE was associated with particles of <0.57 μm in diameter. Our results imply that particulate PBDEs may have long atmospheric residence time and they may be capable of reaching the deeper parts of the human respiratory system. © 2008 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ambient concentrations, gas/particle partitioning and particle-size distribution of polybrominated diphenyl ethers (PBDEs) were investigated in two urban areas (Athens and Heraklion) of Greece. Atmospheric (gas + particle) concentrations of ∑PBDE varied from 21 to 30 pg m -3 in the center of Athens and from 4 to 44 pg m -3 in the suburbs of Heraklion. A predominance of particulate PBDEs was observed in Athens (71-76% in particles), whereas the opposite was evident in Heraklion (69-92% in gas phase). In both urban areas, PBDE particle-size distribution featured a distinct enrichment in smaller particles. A similar trend was also observed in aerosols of a background marine site. For all sampling sites, more than 46% of ∑PBDE was associated with particles of <0.57 μm in diameter. Our results imply that particulate PBDEs may have long atmospheric residence time and they may be capable of reaching the deeper parts of the human respiratory system. © 2008 Elsevier Ltd. All rights reserved. |
Iacovidou, E; Mandalakis, M; Stephanou, E G Chemosphere, 77 (9), pp. 1161–1167, 2009, ISSN: 00456535. @article{iacovidou_occurrence_2009, title = {Occurrence and diurnal variation of polychlorinated biphenyls and polybrominated diphenyl ethers in the background atmosphere of Eastern Mediterranean}, author = {E Iacovidou and M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-71749101095&doi=10.1016%2fj.chemosphere.2009.09.043&partnerID=40&md5=4a75a32f6b1bdd94889204dfe7497dbb}, doi = {10.1016/j.chemosphere.2009.09.043}, issn = {00456535}, year = {2009}, date = {2009-01-01}, journal = {Chemosphere}, volume = {77}, number = {9}, pages = {1161--1167}, abstract = {During a two-week intensive field campaign conducted at a background location of the Eastern Mediterranean, consecutive 10-h air samples were collected under intense photochemical conditions and analyzed for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The average gas-phase concentration of total PCBs and PBDEs was 73 ± 29 and 3.9 ± 2.1 pg m-3, respectively. The study of Clausius-Clapeyron plots and air mass back-trajectories assigned the origin of air masses as the factor largely controlling the variation of PCB and PBDE air concentrations in the study area. Using principal component analysis, discrete differences in PCBs homologue profiles were revealed between day and night samples and attributed to the daytime reaction with hydroxyl radicals. In contrast, PBDE homologue profiles did not show any characteristic day-to-night shifts that could be attributed to hydroxyl radical reaction or photolysis. © 2009 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } During a two-week intensive field campaign conducted at a background location of the Eastern Mediterranean, consecutive 10-h air samples were collected under intense photochemical conditions and analyzed for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The average gas-phase concentration of total PCBs and PBDEs was 73 ± 29 and 3.9 ± 2.1 pg m-3, respectively. The study of Clausius-Clapeyron plots and air mass back-trajectories assigned the origin of air masses as the factor largely controlling the variation of PCB and PBDE air concentrations in the study area. Using principal component analysis, discrete differences in PCBs homologue profiles were revealed between day and night samples and attributed to the daytime reaction with hydroxyl radicals. In contrast, PBDE homologue profiles did not show any characteristic day-to-night shifts that could be attributed to hydroxyl radical reaction or photolysis. © 2009 Elsevier Ltd. All rights reserved. |
Polymenakou, P N; Mandalakis, M; isoSoil Party, Scientific Contaminant-specific isotope analyses as sharp environmental-forensics tools for site characterisation, monitoring and source apportionment of pollutants in soil: the isoSoil project Inproceedings Caravel Hotel, Athens, Greece, 2009, (Publication Title: 2nd National Mikrobiokosmos Conference Type: poster). @inproceedings{polymenakou_contaminant-specific_2009, title = {Contaminant-specific isotope analyses as sharp environmental-forensics tools for site characterisation, monitoring and source apportionment of pollutants in soil: the isoSoil project}, author = {P N Polymenakou and M Mandalakis and Scientific isoSoil Party}, year = {2009}, date = {2009-01-01}, address = {Caravel Hotel, Athens, Greece}, note = {Publication Title: 2nd National Mikrobiokosmos Conference Type: poster}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Polymenakou, P N; Kyrpides, N; Mandalakis, M; Alexandri, S Metagenomic exploration of the newly discovered hydrothermal vent sites in the submarine Kolumbo volcano (Santorini, Greece) Inproceedings Caravel Hotel, Athens, Greece, 2009, (Publication Title: 2nd National Mikrobiokosmos Conference Type: poster). @inproceedings{polymenakou_metagenomic_2009, title = {Metagenomic exploration of the newly discovered hydrothermal vent sites in the submarine Kolumbo volcano (Santorini, Greece)}, author = {P N Polymenakou and N Kyrpides and M Mandalakis and S Alexandri}, year = {2009}, date = {2009-01-01}, address = {Caravel Hotel, Athens, Greece}, note = {Publication Title: 2nd National Mikrobiokosmos Conference Type: poster}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2008 |
Polymenakou, P N; Mandalakis, M; Stephanou, E G; Tselepides, A Particle size distribution of airborne microorganisms and pathogens during an intense African dust event in the eastern Mediterranean Journal Article Environmental Health Perspectives, 116 (3), pp. 292–296, 2008, ISSN: 00916765. @article{polymenakou_particle_2008, title = {Particle size distribution of airborne microorganisms and pathogens during an intense African dust event in the eastern Mediterranean}, author = {P N Polymenakou and M Mandalakis and E G Stephanou and A Tselepides}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40849120624&doi=10.1289%2fehp.10684&partnerID=40&md5=60deb0b8f1ff1ce93a2880b8b87b4a54}, doi = {10.1289/ehp.10684}, issn = {00916765}, year = {2008}, date = {2008-01-01}, journal = {Environmental Health Perspectives}, volume = {116}, number = {3}, pages = {292--296}, abstract = {Background: The distribution of microorganisms, and especially pathogens, over airborne particles of different sizes has been ignored to a large extent, but it could have significant implications regarding the dispersion of these microorganisms across the planet, thus affecting human health. Objectives: We examined the microbial quality of the aerosols over the eastern Mediterranean region during an African storm to determine the size distribution of microorganisms in the air. Methods: We used a five-stage cascade impactor for bioaerosol collection in a coastal city on the eastern Mediterranean Sea during a north African dust storm. Bacterial communities associated with aerosol particles of six different size ranges were characterized following molecular culture-independent methods, regardless of the cell culturability (analysis of 16S rRNA genes). Results: All 16S rDNA clone libraries were diverse, including sequences commonly found in Soil and marine ecosystems. Spore-forming bacteria such as Firmicules dominated large particle sizes (textgreater 3.3 μm), whereas clones affiliated with Actinobacteria (found commonly in soil) and Bacteroidetes (widely distributed in the environment) gradually increased their abundance in aerosol particles of reduced size (textless 33 μm). A large portion of the clones detected at respiratory particle sizes (textless 3.3 μm) were phylogenetic neighbors to human pathogens that have been linked to several diseases. Conclusions: The presence of aerosolized bacteria in small, size particles may have significant implications to human health via intercontinental transportation of pathogens.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background: The distribution of microorganisms, and especially pathogens, over airborne particles of different sizes has been ignored to a large extent, but it could have significant implications regarding the dispersion of these microorganisms across the planet, thus affecting human health. Objectives: We examined the microbial quality of the aerosols over the eastern Mediterranean region during an African storm to determine the size distribution of microorganisms in the air. Methods: We used a five-stage cascade impactor for bioaerosol collection in a coastal city on the eastern Mediterranean Sea during a north African dust storm. Bacterial communities associated with aerosol particles of six different size ranges were characterized following molecular culture-independent methods, regardless of the cell culturability (analysis of 16S rRNA genes). Results: All 16S rDNA clone libraries were diverse, including sequences commonly found in Soil and marine ecosystems. Spore-forming bacteria such as Firmicules dominated large particle sizes (textgreater 3.3 μm), whereas clones affiliated with Actinobacteria (found commonly in soil) and Bacteroidetes (widely distributed in the environment) gradually increased their abundance in aerosol particles of reduced size (textless 33 μm). A large portion of the clones detected at respiratory particle sizes (textless 3.3 μm) were phylogenetic neighbors to human pathogens that have been linked to several diseases. Conclusions: The presence of aerosolized bacteria in small, size particles may have significant implications to human health via intercontinental transportation of pathogens. |
Mandalakis, M; Holmstrand, H; Andersson, P; Gustafsson, O Compound-specific chlorine isotope analysis of polychlorinated biphenyls isolated from Aroclor and Clophen technical mixtures Journal Article Chemosphere, 71 (2), pp. 299–305, 2008, ISSN: 00456535. @article{mandalakis_compound-specific_2008, title = {Compound-specific chlorine isotope analysis of polychlorinated biphenyls isolated from Aroclor and Clophen technical mixtures}, author = {M Mandalakis and H Holmstrand and P Andersson and O Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-39149123565&doi=10.1016%2fj.chemosphere.2007.09.004&partnerID=40&md5=52a8cb261cb38b463c655b3abbeb09ed}, doi = {10.1016/j.chemosphere.2007.09.004}, issn = {00456535}, year = {2008}, date = {2008-01-01}, journal = {Chemosphere}, volume = {71}, number = {2}, pages = {299--305}, abstract = {Compound-specific chlorine isotope analysis (CSIA-Cl) is promising as a novel and powerful method for monitoring in situ degradation of organochlorines in the environment and for source fingerprinting purposes. In order to apply CSIA-Cl in field studies of polychlorinated biphenyls (PCBs), the chlorine isotopic composition (δ37Cl) of individual PCB congeners in source materials must be known. In the present study, we determined δ37Cl of 18 congeners isolated from three widely produced technical mixtures. All congeners provided δ37Cl ranging between -1.9‰ and -3.5‰. Although the comparable products Aroclor 1242 (-2.0‰ to -2.5‰) and Clophen A30 (-1.9‰ to -3.0‰) were synthesized by different industries, they provided similar δ37Cl for the same type of congeners. On the contrary, the more chlorinated congeners present in Aroclor 1254 (-2.1 to -3.5‰) were more 37Cl depleted compared to Aroclor 1242 manufactured by the same company. Overall, δ37Cl of PCB congeners decreased by -0.26 ‰ for each additional chlorine atom. © 2007 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Compound-specific chlorine isotope analysis (CSIA-Cl) is promising as a novel and powerful method for monitoring in situ degradation of organochlorines in the environment and for source fingerprinting purposes. In order to apply CSIA-Cl in field studies of polychlorinated biphenyls (PCBs), the chlorine isotopic composition (δ37Cl) of individual PCB congeners in source materials must be known. In the present study, we determined δ37Cl of 18 congeners isolated from three widely produced technical mixtures. All congeners provided δ37Cl ranging between -1.9‰ and -3.5‰. Although the comparable products Aroclor 1242 (-2.0‰ to -2.5‰) and Clophen A30 (-1.9‰ to -3.0‰) were synthesized by different industries, they provided similar δ37Cl for the same type of congeners. On the contrary, the more chlorinated congeners present in Aroclor 1254 (-2.1 to -3.5‰) were more 37Cl depleted compared to Aroclor 1242 manufactured by the same company. Overall, δ37Cl of PCB congeners decreased by -0.26 ‰ for each additional chlorine atom. © 2007 Elsevier Ltd. All rights reserved. |
Mandalakis, M; Stephanou, E G; Horii, Y; Kannan, K Emerging contaminants in car interiors: Evaluating the impact of airborne PBDEs and PBDD/Fs Journal Article Environmental Science and Technology, 42 (17), pp. 6431–6436, 2008, ISSN: 0013936X. @article{mandalakis_emerging_2008, title = {Emerging contaminants in car interiors: Evaluating the impact of airborne PBDEs and PBDD/Fs}, author = {M Mandalakis and E G Stephanou and Y Horii and K Kannan}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-50849143799&doi=10.1021%2fes7030533&partnerID=40&md5=ffdc03f19db656de13db56ae4912d3a4}, doi = {10.1021/es7030533}, issn = {0013936X}, year = {2008}, date = {2008-01-01}, journal = {Environmental Science and Technology}, volume = {42}, number = {17}, pages = {6431--6436}, abstract = {Air samples from automobile cabins were collected and analyzed for polybrominated diphenyl ethers (PBDEs), polybrominated dibenzofurans (PBDFs), and polybrominated dibenzo-p-dioxins (PBDDs). The concentration of total PBDEs (ΣPBDE; sum of 19 congeners) varied from 0.4 to 2644 pg m -3, with a median of 201 pg m -3, while BDE 47, 99, and 209 collectively accounted for 70 ± 30% of ΣPBDE concentrations. Multiple linear regression analysis revealed that ΣPBDE concentration was significantly influenced by vehicle's age and interior temperature. More specifically, ΣPBDE decreased over time and increased with the rise of temperature. The daily inhalation intake of PBDEs during commuting was estimated to range from 0.5 to 2909 pg day -1 (median 221 pg day -1) and contributed 29% of the overall daily exposure to PBDEs via inhalation. When excluding BDE 209, a lower contribution was calculated for this source (18%), but this was still comparable with residential exposure (22%). The levels of PBDD/Fs were generally below the limits of detection and only in one case were hepta-BDFs positively detected at a concentration of 61 pg m -3. This study demonstrates that car interiors, especially when new, contain high levels of airborne PBDEs and represent a potential route of human exposure via inhalation. © 2008 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Air samples from automobile cabins were collected and analyzed for polybrominated diphenyl ethers (PBDEs), polybrominated dibenzofurans (PBDFs), and polybrominated dibenzo-p-dioxins (PBDDs). The concentration of total PBDEs (ΣPBDE; sum of 19 congeners) varied from 0.4 to 2644 pg m -3, with a median of 201 pg m -3, while BDE 47, 99, and 209 collectively accounted for 70 ± 30% of ΣPBDE concentrations. Multiple linear regression analysis revealed that ΣPBDE concentration was significantly influenced by vehicle's age and interior temperature. More specifically, ΣPBDE decreased over time and increased with the rise of temperature. The daily inhalation intake of PBDEs during commuting was estimated to range from 0.5 to 2909 pg day -1 (median 221 pg day -1) and contributed 29% of the overall daily exposure to PBDEs via inhalation. When excluding BDE 209, a lower contribution was calculated for this source (18%), but this was still comparable with residential exposure (22%). The levels of PBDD/Fs were generally below the limits of detection and only in one case were hepta-BDFs positively detected at a concentration of 61 pg m -3. This study demonstrates that car interiors, especially when new, contain high levels of airborne PBDEs and represent a potential route of human exposure via inhalation. © 2008 American Chemical Society. |
Holmstrand, H; Mandalakis, M; Zencak, Z; Gadomski, D; Andersson, P; Gustafsson, Ö Compound-specific chlorine and bromine-isotope analysis in organohalogens from the ambient environment Inproceedings Geophysical Research Abstracts, pp. EGU2008–A–03637, 2008. @inproceedings{holmstrand_compound-specific_2008, title = {Compound-specific chlorine and bromine-isotope analysis in organohalogens from the ambient environment}, author = {H Holmstrand and M Mandalakis and Z Zencak and D Gadomski and P Andersson and Ö Gustafsson}, url = {https://www.meetings.copernicus.org/www.cosis.net/abstracts/EGU2008/03637/EGU2008-A-03637.pdf}, year = {2008}, date = {2008-01-01}, booktitle = {Geophysical Research Abstracts}, volume = {10}, pages = {EGU2008--A--03637}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Polymenakou, P N; Lampadariou, N; Mandalakis, M; Kouridaki, I; Gontikaki, E; Alexandri, S; Tselepides, A; Lykousis, V Exploring the deep-sea microbial habitats of the Eastern Mediterranean Sea Inproceedings Demokritos Athens, Greece, 2008, (Publication Title: 1st National Mikrobiokosmos Conference Type: Oral Presentation). @inproceedings{polymenakou_exploring_2008, title = {Exploring the deep-sea microbial habitats of the Eastern Mediterranean Sea}, author = {P N Polymenakou and N Lampadariou and M Mandalakis and I Kouridaki and E Gontikaki and S Alexandri and A Tselepides and V Lykousis}, year = {2008}, date = {2008-01-01}, address = {Demokritos Athens, Greece}, note = {Publication Title: 1st National Mikrobiokosmos Conference Type: Oral Presentation}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Polymenakou, P N; Lampadariou, N; Mandalakis, M; Tselepides, A The unique bacterial diversity of the Eastern Mediterranean deep-sea oxic sediments Inproceedings 2008, (Publication Title: EMBO Workshop: Microbial diversity and metagenomics: science, technology, applications and regulatory affairs Type: Invited Oral Presentation: EMBO poster prize). @inproceedings{polymenakou_unique_2008, title = {The unique bacterial diversity of the Eastern Mediterranean deep-sea oxic sediments}, author = {P N Polymenakou and N Lampadariou and M Mandalakis and A Tselepides}, year = {2008}, date = {2008-01-01}, note = {Publication Title: EMBO Workshop: Microbial diversity and metagenomics: science, technology, applications and regulatory affairs Type: Invited Oral Presentation: EMBO poster prize}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Stephanou, E G; Mandalakis, M; Tsapakis, M; Apostolaki, M Study of PAHs’ and PCBs’ occurrence and fate in marine aerosols of Eastern Mediterranean Inproceedings Goldschmidt Conference Abstracts, pp. 12S, A897, 2008. @inproceedings{stephanou_study_2008, title = {Study of PAHs’ and PCBs’ occurrence and fate in marine aerosols of Eastern Mediterranean}, author = {E G Stephanou and M Mandalakis and M Tsapakis and M Apostolaki}, year = {2008}, date = {2008-01-01}, booktitle = {Goldschmidt Conference Abstracts}, volume = {72}, pages = {12S, A897}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Mandalakis, M; Atsarou, V; Stephanou, E G Airborne PBDEs in specialized occupational settings, houses and outdoor urban areas in Greece Journal Article Environmental Pollution, 155 (2), pp. 375–382, 2008, ISSN: 02697491. @article{mandalakis_airborne_2008, title = {Airborne PBDEs in specialized occupational settings, houses and outdoor urban areas in Greece}, author = {M Mandalakis and V Atsarou and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-48449083661&doi=10.1016%2fj.envpol.2007.11.016&partnerID=40&md5=118efe97145f295d84bb7bfbe545d5be}, doi = {10.1016/j.envpol.2007.11.016}, issn = {02697491}, year = {2008}, date = {2008-01-01}, journal = {Environmental Pollution}, volume = {155}, number = {2}, pages = {375--382}, abstract = {Airborne polybrominated diphenyl ethers (PBDEs) were measured in workplaces, homes and urban outdoor air in Greece. The geometric mean concentrations of total PBDEs (sum of 19 congeners) in offices (205 pg m-3), internet cafes/computer rooms (127 pg m-3) and computers/electronics shops (85 pg m-3) were significantly higher than those in furniture stores (12 pg m-3), homes (8 pg m-3) and outdoor air (18 pg m-3). The daily inhalation intake of PBDEs estimated for the employees of the four occupational settings ranged from 0.2 to 1.4 ng day-1 and it was significantly lower than the expected dietary intake (∼77 ng day-1). Although inhalation generally represented a small fraction of the overall daily exposure to PBDEs (∼1%), the results from a heavily contaminated office (10 848 pg m-3 of total PBDEs) indicated that the intake from this route (65 ng day-1) may, in some extreme cases, be as important as diet. © 2007 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Airborne polybrominated diphenyl ethers (PBDEs) were measured in workplaces, homes and urban outdoor air in Greece. The geometric mean concentrations of total PBDEs (sum of 19 congeners) in offices (205 pg m-3), internet cafes/computer rooms (127 pg m-3) and computers/electronics shops (85 pg m-3) were significantly higher than those in furniture stores (12 pg m-3), homes (8 pg m-3) and outdoor air (18 pg m-3). The daily inhalation intake of PBDEs estimated for the employees of the four occupational settings ranged from 0.2 to 1.4 ng day-1 and it was significantly lower than the expected dietary intake (∼77 ng day-1). Although inhalation generally represented a small fraction of the overall daily exposure to PBDEs (∼1%), the results from a heavily contaminated office (10 848 pg m-3 of total PBDEs) indicated that the intake from this route (65 ng day-1) may, in some extreme cases, be as important as diet. © 2007 Elsevier Ltd. All rights reserved. |
2007 |
Mandalakis, M; Stephanou, E G Atmospheric concentration characteristics and gas-particle partitioning of PCBs in a rural area of eastern Germany Journal Article Environmental Pollution, 147 (1), pp. 211–221, 2007, ISSN: 02697491. @article{mandalakis_atmospheric_2007, title = {Atmospheric concentration characteristics and gas-particle partitioning of PCBs in a rural area of eastern Germany}, author = {M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33847323992&doi=10.1016%2fj.envpol.2006.08.035&partnerID=40&md5=119f2d5830ea3cd3b85b8d99853ab5b4}, doi = {10.1016/j.envpol.2006.08.035}, issn = {02697491}, year = {2007}, date = {2007-01-01}, journal = {Environmental Pollution}, volume = {147}, number = {1}, pages = {211--221}, abstract = {Atmospheric concentrations of polychlorinated biphenyls (PCBs) were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany. The average total concentration of PCBs was 110 ± 80 pg m-3 and they were predominately present in the gas phase (∼95%). Composition of individual congeners closely resembled those of Clophen A30 and Aroclor 1232. Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius-Clapeyron plots (-4500 to -8000) indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Particle-gas partitioning coefficients (KP) of PCBs were well correlated with the respective sub-cooled vapor pressures (PLo), but the slopes obtained from log KP versus log PLo plots (-0.16 to -0.59) deviated significantly from the expected value of -1. Overall, gas-particle partitioning of PCBs was better simulated by Junge-Pankow than octanol/air partition coefficient-based model. © 2006 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Atmospheric concentrations of polychlorinated biphenyls (PCBs) were measured in 14 successive daytime and nighttime air samples collected from Melpitz, a rural site in eastern Germany. The average total concentration of PCBs was 110 ± 80 pg m-3 and they were predominately present in the gas phase (∼95%). Composition of individual congeners closely resembled those of Clophen A30 and Aroclor 1232. Partial vapor pressures of PCBs were well correlated with temperature and the steep slopes obtained from Clausius-Clapeyron plots (-4500 to -8000) indicated that evaporation from adjacent land surfaces still controls the atmospheric levels of these pollutants. Particle-gas partitioning coefficients (KP) of PCBs were well correlated with the respective sub-cooled vapor pressures (PLo), but the slopes obtained from log KP versus log PLo plots (-0.16 to -0.59) deviated significantly from the expected value of -1. Overall, gas-particle partitioning of PCBs was better simulated by Junge-Pankow than octanol/air partition coefficient-based model. © 2006 Elsevier Ltd. All rights reserved. |
Holmstrand, H; Mandalakis, M; Zencak, Z; Andersson, P; Gustafsson, O Chemosphere, 69 (10), pp. 1533–1539, 2007, ISSN: 00456535. @article{holmstrand_first_2007, title = {First compound-specific chlorine-isotope analysis of environmentally-bioaccumulated organochlorines indicates a degradation-relatable kinetic isotope effect for DDT}, author = {H Holmstrand and M Mandalakis and Z Zencak and P Andersson and O Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348894035&doi=10.1016%2fj.chemosphere.2007.05.067&partnerID=40&md5=693f22cd95fe2bd4dd3109505dde5008}, doi = {10.1016/j.chemosphere.2007.05.067}, issn = {00456535}, year = {2007}, date = {2007-01-01}, journal = {Chemosphere}, volume = {69}, number = {10}, pages = {1533--1539}, abstract = {Compound-specific chlorine-isotope analysis (CSIA-Cl) of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (p,p′-DDE) in blubber from Baltic Grey seal (Halichoerus grypus) was performed in order to investigate if a kinetic isotope effect (KIE) could be observed concomitant to environmental degradation of DDT. The δ37Cl of p,p′-DDT and p,p′-DDE were -0.69 ± 0.21‰ and -2.98 ± 0.57‰ (1σ}, keywords = {}, pubstate = {published}, tppubtype = {article} } Compound-specific chlorine-isotope analysis (CSIA-Cl) of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (p,p′-DDE) in blubber from Baltic Grey seal (Halichoerus grypus) was performed in order to investigate if a kinetic isotope effect (KIE) could be observed concomitant to environmental degradation of DDT. The δ37Cl of p,p′-DDT and p,p′-DDE were -0.69 ± 0.21‰ and -2.98 ± 0.57‰ (1σ |
2006 |
Mandalakis, M; Atsarou, V; Stephanou, E G Indoor air levels of polybrominated diphenyl ethers in homes and workplaces in Greece Inproceedings Organohalogen Compounds, pp. 492–494, 2006. @inproceedings{mandalakis_indoor_2006, title = {Indoor air levels of polybrominated diphenyl ethers in homes and workplaces in Greece}, author = {M Mandalakis and V Atsarou and E G Stephanou}, year = {2006}, date = {2006-01-01}, booktitle = {Organohalogen Compounds}, volume = {68}, pages = {492--494}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Teuten, E L; Johnson, C G; Mandalakis, M; Asplund, L; Gustafsson, O; Unger, M; Marsh, G; Reddy, C M Spectral characterization of two bioaccumulated methoxylated polybrominated diphenyl ethers Journal Article Chemosphere, 62 (2), pp. 197–203, 2006, ISSN: 00456535. @article{teuten_spectral_2006, title = {Spectral characterization of two bioaccumulated methoxylated polybrominated diphenyl ethers}, author = {E L Teuten and C G Johnson and M Mandalakis and L Asplund and O Gustafsson and M Unger and G Marsh and C M Reddy}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-28444446663&doi=10.1016%2fj.chemosphere.2005.05.023&partnerID=40&md5=19cfac57ec819f2b14073b66d0a47aa0}, doi = {10.1016/j.chemosphere.2005.05.023}, issn = {00456535}, year = {2006}, date = {2006-01-01}, journal = {Chemosphere}, volume = {62}, number = {2}, pages = {197--203}, abstract = {Two methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were isolated from a True's beaked whale (Mesoplodon mirus) and identified by NMR ( 1H, 1H-1H and 1H-13C) and high resolution mass spectrometry as 2-(2′,4′-dibromophenoxy)-3,5- dibromoanisole (6-MeO-BDE47) and 2-(2′,4′-dibromophenoxy)-4,6- dibromoanisole (2′-MeO-BDE68). Previously the structures of these bioaccumulated compounds have been determined by comparison of their mass spectra and gas chromatographic (GC) retention times with those of authentic standards. While this method is accepted and generally successful, NMR of the isolated compounds allows us to definitively identify the congeners. Our characterizations are consistent with those made for MeO-PBDEs in other organisms, identified by chromatographic methods. © 2005 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were isolated from a True's beaked whale (Mesoplodon mirus) and identified by NMR ( 1H, 1H-1H and 1H-13C) and high resolution mass spectrometry as 2-(2′,4′-dibromophenoxy)-3,5- dibromoanisole (6-MeO-BDE47) and 2-(2′,4′-dibromophenoxy)-4,6- dibromoanisole (2′-MeO-BDE68). Previously the structures of these bioaccumulated compounds have been determined by comparison of their mass spectra and gas chromatographic (GC) retention times with those of authentic standards. While this method is accepted and generally successful, NMR of the isolated compounds allows us to definitively identify the congeners. Our characterizations are consistent with those made for MeO-PBDEs in other organisms, identified by chromatographic methods. © 2005 Elsevier Ltd. All rights reserved. |
Holmstrand, H; Mandalakis, M; Zencak, Z; Gustafsson, Ö; Andersson, P Chlorine isotope fractionation of a semi-volatile organochlorine compound during preparative megabore-column capillary gas chromatography Journal Article Journal of Chromatography A, 1103 (1), pp. 133–138, 2006, ISSN: 00219673. @article{holmstrand_chlorine_2006, title = {Chlorine isotope fractionation of a semi-volatile organochlorine compound during preparative megabore-column capillary gas chromatography}, author = {H Holmstrand and M Mandalakis and Z Zencak and Ö Gustafsson and P Andersson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-29844436046&doi=10.1016%2fj.chroma.2005.11.009&partnerID=40&md5=3c4fbc5f3d5bb7f9913400ab81b2cf11}, doi = {10.1016/j.chroma.2005.11.009}, issn = {00219673}, year = {2006}, date = {2006-01-01}, journal = {Journal of Chromatography A}, volume = {1103}, number = {1}, pages = {133--138}, abstract = {Chlorine isotope fractionation during preparative capillary gas chromatography (pcGC) was investigated using 1,1,1-trichloro-2,2-bis(p- chlorophenyl)ethane (DDT) as a model compound for semi-volatile organochlorine (OCl) molecules. Chlorine isotope analysis by thermal ionization mass spectrometry revealed no significant alteration of the chlorine isotope composition when the whole peaks were collected in pcGC (δ37Cl -3.2‰ versus -3.6‰ for the unprocessed DDT, ±0.5‰ SD). However, distinct isotope fractionations were measured for the front (δ37Cl -5.1‰) and tail (δ37Cl -1.8‰) segments of partially collected samples. Isolation of individual OCls by pcGC enables accurate off-line chlorine isotope analysis, and thus facilitates the investigation of naturally occurring OCls. © 2005 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chlorine isotope fractionation during preparative capillary gas chromatography (pcGC) was investigated using 1,1,1-trichloro-2,2-bis(p- chlorophenyl)ethane (DDT) as a model compound for semi-volatile organochlorine (OCl) molecules. Chlorine isotope analysis by thermal ionization mass spectrometry revealed no significant alteration of the chlorine isotope composition when the whole peaks were collected in pcGC (δ37Cl -3.2‰ versus -3.6‰ for the unprocessed DDT, ±0.5‰ SD). However, distinct isotope fractionations were measured for the front (δ37Cl -5.1‰) and tail (δ37Cl -1.8‰) segments of partially collected samples. Isolation of individual OCls by pcGC enables accurate off-line chlorine isotope analysis, and thus facilitates the investigation of naturally occurring OCls. © 2005 Elsevier B.V. All rights reserved. |
Holmstrand, H; Gadomski, D; Mandalakis, M; Tysklind, M; Irvine, R; Andersson, P; Gustafsson, Ö Origin of PCDDs in Ball Clay assessed with compound-specific chlorine isotope analysis and radiocarbon dating Journal Article Environmental Science and Technology, 40 (12), pp. 3730–3735, 2006, ISSN: 0013936X. @article{holmstrand_origin_2006, title = {Origin of PCDDs in Ball Clay assessed with compound-specific chlorine isotope analysis and radiocarbon dating}, author = {H Holmstrand and D Gadomski and M Mandalakis and M Tysklind and R Irvine and P Andersson and Ö Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745152689&doi=10.1021%2fes0602142&partnerID=40&md5=bd5ef3dfec20a26979baa18cc19fc427}, doi = {10.1021/es0602142}, issn = {0013936X}, year = {2006}, date = {2006-01-01}, journal = {Environmental Science and Technology}, volume = {40}, number = {12}, pages = {3730--3735}, abstract = {Polychlorinated dibenzo-p-dioxins (PCDDs) of high concentrations in a ball clay deposit from the Mississippi Embayment were found to be consistent with a natural abiotic and non-pyrogenic origin by investigation with bulk radiocarbon analysis, compound-specific chlorine isotope analysis (CSIA- δ37Cl) of octachlorodibenzo-p-dioxin (OCDD), and black carbon (BC) analysis. The conventional radiocarbon date of total organic carbon from a depth of approximately 10 m in three parallel cores ranged from 14 700 years to >48 000 years, indicating that the strata with elevated levels of PCDDs have remained isolated from recent anthropogenic input in these >40 Ma old clay sediments. The CSIA-δ37Cl of OCDD yielded a δ37Cl of -0.2%, which is significantly higher than the postulated range for biotic chlorination by chloroperoxidase enzymes, -11 to -10‰, and falls within the known range for abiotic organochlorines, -6 to +3‰. The absence of correlations between concentrations of PCDDs and corresponding pyrogenic black carbon (BC), together with estimations of BC sorptive loadings and the absence of polychlorinated dibenzofurans (PCDFs), suggest that vegetation fires did not form these ball-clay PCDDs. Results from this study indicate that the high levels of the toxic and carcinogenic PCDDs found in kaolinite-bearing clays may result from natural abiotic formation via in situ surface-promoted reactions on the clay mineral, including a so-far unknown organic precursor, rather than being the result of anthropogenic contamination. © 2006 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polychlorinated dibenzo-p-dioxins (PCDDs) of high concentrations in a ball clay deposit from the Mississippi Embayment were found to be consistent with a natural abiotic and non-pyrogenic origin by investigation with bulk radiocarbon analysis, compound-specific chlorine isotope analysis (CSIA- δ37Cl) of octachlorodibenzo-p-dioxin (OCDD), and black carbon (BC) analysis. The conventional radiocarbon date of total organic carbon from a depth of approximately 10 m in three parallel cores ranged from 14 700 years to >48 000 years, indicating that the strata with elevated levels of PCDDs have remained isolated from recent anthropogenic input in these >40 Ma old clay sediments. The CSIA-δ37Cl of OCDD yielded a δ37Cl of -0.2%, which is significantly higher than the postulated range for biotic chlorination by chloroperoxidase enzymes, -11 to -10‰, and falls within the known range for abiotic organochlorines, -6 to +3‰. The absence of correlations between concentrations of PCDDs and corresponding pyrogenic black carbon (BC), together with estimations of BC sorptive loadings and the absence of polychlorinated dibenzofurans (PCDFs), suggest that vegetation fires did not form these ball-clay PCDDs. Results from this study indicate that the high levels of the toxic and carcinogenic PCDDs found in kaolinite-bearing clays may result from natural abiotic formation via in situ surface-promoted reactions on the clay mineral, including a so-far unknown organic precursor, rather than being the result of anthropogenic contamination. © 2006 American Chemical Society. |
Holmstrand, H; Andersson, P; Gustafsson, Ö; Mandalakis, M; Zencak, Z; Gadomski, D Development and applications of compound-specific chlorine isotope analysis of organochlorines: The cases of PCDD in UṠ. ball clay and DDT in the Baltic environment Inproceedings Organohalogen Compounds, pp. 13–16, 2006. @inproceedings{holmstrand_development_2006, title = {Development and applications of compound-specific chlorine isotope analysis of organochlorines: The cases of PCDD in UṠ. ball clay and DDT in the Baltic environment}, author = {H Holmstrand and P Andersson and Ö Gustafsson and M Mandalakis and Z Zencak and D Gadomski}, year = {2006}, date = {2006-01-01}, booktitle = {Organohalogen Compounds}, volume = {68}, pages = {13--16}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Zencak, Z; Holmstrand, H; Mandalakis, M; Unger, M; Andersson, P; Gustafsson, Ö Compound specific isotope analysis indicates abiotic chlorination as formation mechanism of tris(4-chlorophenyl)methane Inproceedings Organohalogen Compounds, pp. 2314–2317, Oslo, Norway, 2006. @inproceedings{zencak_compound_2006, title = {Compound specific isotope analysis indicates abiotic chlorination as formation mechanism of tris(4-chlorophenyl)methane}, author = {Z Zencak and H Holmstrand and M Mandalakis and M Unger and P Andersson and Ö Gustafsson}, url = {http://dioxin20xx.org/wp-content/uploads/pdfs/2006/06-530.pdf}, year = {2006}, date = {2006-01-01}, booktitle = {Organohalogen Compounds}, volume = {68}, pages = {2314--2317}, address = {Oslo, Norway}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2005 |
Mandalakis, M; Apostolaki, M; Stephanou, E G; Stavrakakis, S Mass budget and dynamics of polychlorinated biphenyls in the eastern Mediterranean Sea Journal Article Global Biogeochemical Cycles, 19 (3), pp. 1–16, 2005, ISSN: 08866236. @article{mandalakis_mass_2005, title = {Mass budget and dynamics of polychlorinated biphenyls in the eastern Mediterranean Sea}, author = {M Mandalakis and M Apostolaki and E G Stephanou and S Stavrakakis}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-27744457044&doi=10.1029%2f2004GB002403&partnerID=40&md5=c448a5c9bc9bcb79e6dc5fc720676fec}, doi = {10.1029/2004GB002403}, issn = {08866236}, year = {2005}, date = {2005-01-01}, journal = {Global Biogeochemical Cycles}, volume = {19}, number = {3}, pages = {1--16}, abstract = {Polychlorinated biphenyls (PCBs) were measured in dry deposition and sediment trap samples from the eastern Mediterranean and the results of the present and previous studies were synthesized in order to construct a mass balance budget describing the status and dynamics of PCBs in this region. According to our calculations, the burden of total PCBs in the euphotic zone of the eastern Mediterranean should approach 84,000 kg, while the corresponding pool in the overlying atmosphere should be about 162 kg. The atmospheric input of PCBs in the respective water basin through dry and wet deposition should be 300 and 1300 kg yr-1, respectively. On the contrary, air-sea exchange should cause a net volatilization of PCBs from seawater to the atmosphere by 3150 kg yr-1. Moreover, PCBs are removed from the water column with a settling flux of 350 kg yr-1 and under steady state conditions, an additional input of these pollutants should be required to counterbalance the outflows from the water basin. The discharge of urban and industrial sewage, riverine input and transport of more polluted surface waters from western to eastern Mediterranean may account for most of this inflow. In the atmospheric compartment, the removal flux of PCBs due to their destruction by hydroxyl radicals (6650 kg yr-1) was approximately 4 times higher than their deposition flux (wet plus dry). On the basis of these data, 5100 kg of PCBs should enter into the atmosphere of eastern Mediterranean annually in order to achieve steady state conditions. This influx may result from long or short range transport of atmospheric PCBs emitted from contaminated terrestrial surfaces. Copyright 2005 by the American Geophysical Union.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polychlorinated biphenyls (PCBs) were measured in dry deposition and sediment trap samples from the eastern Mediterranean and the results of the present and previous studies were synthesized in order to construct a mass balance budget describing the status and dynamics of PCBs in this region. According to our calculations, the burden of total PCBs in the euphotic zone of the eastern Mediterranean should approach 84,000 kg, while the corresponding pool in the overlying atmosphere should be about 162 kg. The atmospheric input of PCBs in the respective water basin through dry and wet deposition should be 300 and 1300 kg yr-1, respectively. On the contrary, air-sea exchange should cause a net volatilization of PCBs from seawater to the atmosphere by 3150 kg yr-1. Moreover, PCBs are removed from the water column with a settling flux of 350 kg yr-1 and under steady state conditions, an additional input of these pollutants should be required to counterbalance the outflows from the water basin. The discharge of urban and industrial sewage, riverine input and transport of more polluted surface waters from western to eastern Mediterranean may account for most of this inflow. In the atmospheric compartment, the removal flux of PCBs due to their destruction by hydroxyl radicals (6650 kg yr-1) was approximately 4 times higher than their deposition flux (wet plus dry). On the basis of these data, 5100 kg of PCBs should enter into the atmosphere of eastern Mediterranean annually in order to achieve steady state conditions. This influx may result from long or short range transport of atmospheric PCBs emitted from contaminated terrestrial surfaces. Copyright 2005 by the American Geophysical Union. |
Mandalakis, M; Gustafsson, Ö; Alsberg, T; Egebäck, A -L; Reddy, C M; Xu, L; Klanova, J; Holoubek, I; Stephanou, E G Contribution of biomass burning to atmospheric polycyclic aromatic hydrocarbons at three european background sites Journal Article Environmental Science and Technology, 39 (9), pp. 2976–2982, 2005, ISSN: 0013936X. @article{mandalakis_contribution_2005, title = {Contribution of biomass burning to atmospheric polycyclic aromatic hydrocarbons at three european background sites}, author = {M Mandalakis and Ö Gustafsson and T Alsberg and A -L Egebäck and C M Reddy and L Xu and J Klanova and I Holoubek and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18344396135&doi=10.1021%2fes048184v&partnerID=40&md5=e821f5d70d448ac54af11b534fa61cfa}, doi = {10.1021/es048184v}, issn = {0013936X}, year = {2005}, date = {2005-01-01}, journal = {Environmental Science and Technology}, volume = {39}, number = {9}, pages = {2976--2982}, abstract = {Radiocarbon analysis of atmospheric polycyclic aromatic hydrocarbons (PAHs) from three background areas in Sweden, Croatia, and Greece was performed to apportion their origin between fossil and biomass combustion. Diagnostic ratios of PAHs implied that wood and coal combustion was relatively more important in the northern European site, while combustion of fossil fuels was the dominant source of PAHs to the two central-southern European background sites. The radiocarbon content (Δ14C) of atmospheric PAHs in Sweden ranged between -388‰ and -381‰, while more depleted values were observed for Greece (-914‰) and Croatia (-888‰). Using a 14C isotopic mass balance model it was calculated that biomass burning contributes nearly 10% of the total PAH burden in the studied southern European atmosphere with fossil fuel combustion making up the 90% balance. In contrast, biomass burning contributes about 50% of total PAHs in the atmosphere at the Swedish site. Our results suggest that the relative contributions of biomass burning and fossil fuels to atmospheric PAHs may differ considerably between countries, and therefore, different national control strategies might be needed if a further reduction of these pollutants is to be achieved on a continental-global scale. © 2005 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Radiocarbon analysis of atmospheric polycyclic aromatic hydrocarbons (PAHs) from three background areas in Sweden, Croatia, and Greece was performed to apportion their origin between fossil and biomass combustion. Diagnostic ratios of PAHs implied that wood and coal combustion was relatively more important in the northern European site, while combustion of fossil fuels was the dominant source of PAHs to the two central-southern European background sites. The radiocarbon content (Δ14C) of atmospheric PAHs in Sweden ranged between -388‰ and -381‰, while more depleted values were observed for Greece (-914‰) and Croatia (-888‰). Using a 14C isotopic mass balance model it was calculated that biomass burning contributes nearly 10% of the total PAH burden in the studied southern European atmosphere with fossil fuel combustion making up the 90% balance. In contrast, biomass burning contributes about 50% of total PAHs in the atmosphere at the Swedish site. Our results suggest that the relative contributions of biomass burning and fossil fuels to atmospheric PAHs may differ considerably between countries, and therefore, different national control strategies might be needed if a further reduction of these pollutants is to be achieved on a continental-global scale. © 2005 American Chemical Society. |
Gustafsson, Ö; Elmquist, M; Kukulska, Z; Cornelissen, G; Mandalakis, M; Persson, J; Bucheli, T; Reddy, C On the analysis of black carbon in sediments: Evaluation of field data for geochemical consistency Inproceedings Geophysical Research Abstracts, pp. EGU05–A–06089, 2005. @inproceedings{gustafsson_analysis_2005, title = {On the analysis of black carbon in sediments: Evaluation of field data for geochemical consistency}, author = {Ö Gustafsson and M Elmquist and Z Kukulska and G Cornelissen and M Mandalakis and J Persson and T Bucheli and C Reddy}, year = {2005}, date = {2005-01-01}, booktitle = {Geophysical Research Abstracts}, volume = {7}, pages = {EGU05--A--06089}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2004 |
Mandalakis, M; Stephanou, E G Wet deposition of polychlorinated biphenyls in the eastern Mediterranean Journal Article Environmental Science and Technology, 38 (11), pp. 3011–3018, 2004, ISSN: 0013936X. @article{mandalakis_wet_2004, title = {Wet deposition of polychlorinated biphenyls in the eastern Mediterranean}, author = {M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2542447209&doi=10.1021%2fes030078q&partnerID=40&md5=62f74bf720be4dfe07eb56dbbd3b4ed2}, doi = {10.1021/es030078q}, issn = {0013936X}, year = {2004}, date = {2004-01-01}, journal = {Environmental Science and Technology}, volume = {38}, number = {11}, pages = {3011--3018}, abstract = {The concentrations of polychlorinated biphenyls (PCBs) were measured in rain samples collected from a semi-urban and a marine background site of the eastern Mediterranean. The concentration of ΣPCB (sum of 54 PCB congeners) in the city of Heraklion (2.9 ± 1.9 ng L-1) was not significantly higher than the corresponding concentration measured at the background sampling station of Finokalia (1.9 ± 0.9 ng L-1). In both sites, the sum of tri- and tetrachlorinated congeners accounted for more than 55% of ΣPCB in rainwater. For all samples, the percentage of particle-bound PCBs ranged between 6.6% and 63.8%, providing an average value of 31 ± 18%. The washout ratios of particulate PCBs (Wp) were constant for individual congeners regardless the degree of chlorination. Average W P values ranged between 1.9 × 105 and 5.2 × 105 while a value of 2.7(±1.3) × 105 was deduced for ΣPCB. The corresponding washout ratios for gaseous PCBs were substantially lower and ranged between 7 × 103 (PCB 99) and 1. 3 × 105 (PCB 180). Washout ratios of gaseous PCBs were also calculated based on Henry's law, and they were found to be 30-920 times lower than those obtained from field measurements. On the basis of our data, the wet deposition flux of ΣPCB in the eastern Mediterranean should approach 820 ng m-2 yr-1. This flux is similar with the values recently reported for several background sites of the United States and Europe, but it is 1 order of magnitude lower than the flux of PCBs measured in the western Mediterranean 16 yr ago.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The concentrations of polychlorinated biphenyls (PCBs) were measured in rain samples collected from a semi-urban and a marine background site of the eastern Mediterranean. The concentration of ΣPCB (sum of 54 PCB congeners) in the city of Heraklion (2.9 ± 1.9 ng L-1) was not significantly higher than the corresponding concentration measured at the background sampling station of Finokalia (1.9 ± 0.9 ng L-1). In both sites, the sum of tri- and tetrachlorinated congeners accounted for more than 55% of ΣPCB in rainwater. For all samples, the percentage of particle-bound PCBs ranged between 6.6% and 63.8%, providing an average value of 31 ± 18%. The washout ratios of particulate PCBs (Wp) were constant for individual congeners regardless the degree of chlorination. Average W P values ranged between 1.9 × 105 and 5.2 × 105 while a value of 2.7(±1.3) × 105 was deduced for ΣPCB. The corresponding washout ratios for gaseous PCBs were substantially lower and ranged between 7 × 103 (PCB 99) and 1. 3 × 105 (PCB 180). Washout ratios of gaseous PCBs were also calculated based on Henry's law, and they were found to be 30-920 times lower than those obtained from field measurements. On the basis of our data, the wet deposition flux of ΣPCB in the eastern Mediterranean should approach 820 ng m-2 yr-1. This flux is similar with the values recently reported for several background sites of the United States and Europe, but it is 1 order of magnitude lower than the flux of PCBs measured in the western Mediterranean 16 yr ago. |
Mandalakis, M; Zebühr, Y; Gustafsson, Ö Efficient isolation of polyaromatic fraction from aliphatic compounds in complex extracts using dimethylformamide-pentane partitionings Journal Article Journal of Chromatography A, 1041 (1-2), pp. 111–117, 2004, ISSN: 00219673. @article{mandalakis_efficient_2004, title = {Efficient isolation of polyaromatic fraction from aliphatic compounds in complex extracts using dimethylformamide-pentane partitionings}, author = {M Mandalakis and Y Zebühr and Ö Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942567872&doi=10.1016%2fj.chroma.2004.04.038&partnerID=40&md5=e5e205d42a77a25eb4e3a323824426fd}, doi = {10.1016/j.chroma.2004.04.038}, issn = {00219673}, year = {2004}, date = {2004-01-01}, journal = {Journal of Chromatography A}, volume = {1041}, number = {1-2}, pages = {111--117}, abstract = {A liquid-liquid partitioning method was optimized for the rapid and quantitative separation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from aliphatic hydrocarbons in complex primary extracts. This technique was based on the selective extraction of PAHs and PCBs from an aliphatic solvent into dimethylformamide (DMF). Partition experiments demonstrated that the optimal performance was achieved with a DMF (5% H 2O)-n-pentane binary system. The optimized application of two consecutive DMF (5% H2O)-n-pentane treatments to extracts from two different polluted sediments facilitated the elimination of alkanes and unresolved complex mixture by more than 94% while the average recoveries of spiked deuterated-PAHs and 13C labeled PCBs ranged from 84 to 94 and 75 to 96%, respectively. © 2004 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A liquid-liquid partitioning method was optimized for the rapid and quantitative separation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from aliphatic hydrocarbons in complex primary extracts. This technique was based on the selective extraction of PAHs and PCBs from an aliphatic solvent into dimethylformamide (DMF). Partition experiments demonstrated that the optimal performance was achieved with a DMF (5% H 2O)-n-pentane binary system. The optimized application of two consecutive DMF (5% H2O)-n-pentane treatments to extracts from two different polluted sediments facilitated the elimination of alkanes and unresolved complex mixture by more than 94% while the average recoveries of spiked deuterated-PAHs and 13C labeled PCBs ranged from 84 to 94 and 75 to 96%, respectively. © 2004 Elsevier B.V. All rights reserved. |
Mandalakis, M; Gustafsson, Ö; Reddy, C M; Xu, L Radiocarbon apportionment of fossil versus biofuel combustion sources of polycyclic aromatic hydrocarbons in the Stockholm metropolitan area Journal Article Environmental Science and Technology, 38 (20), pp. 5344–5349, 2004, ISSN: 0013936X. @article{mandalakis_radiocarbon_2004, title = {Radiocarbon apportionment of fossil versus biofuel combustion sources of polycyclic aromatic hydrocarbons in the Stockholm metropolitan area}, author = {M Mandalakis and Ö Gustafsson and C M Reddy and L Xu}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044256299&doi=10.1021%2fes049088x&partnerID=40&md5=dada99d9431117db76b594464cebbbb1}, doi = {10.1021/es049088x}, issn = {0013936X}, year = {2004}, date = {2004-01-01}, journal = {Environmental Science and Technology}, volume = {38}, number = {20}, pages = {5344--5349}, abstract = {Source-diagnostic markers and the isotopic composition of polycyclic aromatic hydrocarbons (PAHs) were examined in surface sediments from the greater Stockholm waterways to deduce the contribution from biomass sources to the environmental PAH load. The summed concentration of 20 PAHs ranged from 0.8 to 45.1 μg/g (dry weight) and exhibited a steep decline with increasing distance from the city center evidencing that sources within the metropolitan area of Stockholm dominate its PAH burden. Several diagnostic PAH ratios indicated an overwhelming predominance of pyrogenic sources over the petrogenic ones, while retene and 1,7-dimethylphenanthrene were unable to correctly evaluate the contribution from biomass combustion. The stable carbon isotope composition (δ13C) of individual PAHs ranged from -24.8 to -27.0% but also was proved inefficient to discriminate between different types of fuels due to the overlapping signals in various sources. The Δ14C values of PAHs ranged between -550.4 and -934.1%, indicating a clear predominance of fossil fuel sources. By using an isotopic mass balance approach, we estimated that on average 17 ± 9% of PAHs derived from biomass combustion. This radiocarbon apportionment, in conjunction with detailed energy statistics for the Stockholm region, revealed that the ambient PAH burden is roughly similar, per unit energy produced, from fossil fuels and biofuels. Societies' shifting energy policies toward a larger reliance on biofuels may thus not lead to further deterioration of air quality and respiratory ailments for the urban population.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Source-diagnostic markers and the isotopic composition of polycyclic aromatic hydrocarbons (PAHs) were examined in surface sediments from the greater Stockholm waterways to deduce the contribution from biomass sources to the environmental PAH load. The summed concentration of 20 PAHs ranged from 0.8 to 45.1 μg/g (dry weight) and exhibited a steep decline with increasing distance from the city center evidencing that sources within the metropolitan area of Stockholm dominate its PAH burden. Several diagnostic PAH ratios indicated an overwhelming predominance of pyrogenic sources over the petrogenic ones, while retene and 1,7-dimethylphenanthrene were unable to correctly evaluate the contribution from biomass combustion. The stable carbon isotope composition (δ13C) of individual PAHs ranged from -24.8 to -27.0% but also was proved inefficient to discriminate between different types of fuels due to the overlapping signals in various sources. The Δ14C values of PAHs ranged between -550.4 and -934.1%, indicating a clear predominance of fossil fuel sources. By using an isotopic mass balance approach, we estimated that on average 17 ± 9% of PAHs derived from biomass combustion. This radiocarbon apportionment, in conjunction with detailed energy statistics for the Stockholm region, revealed that the ambient PAH burden is roughly similar, per unit energy produced, from fossil fuels and biofuels. Societies' shifting energy policies toward a larger reliance on biofuels may thus not lead to further deterioration of air quality and respiratory ailments for the urban population. |
2003 |
Mandalakis, M; Stephanou, E G Loss Processes of PCBs in the subtropical atmosphere: Study of PCB-OH radical reactions in eastern Mediterranean Inproceedings Organohalogen Compounds, pp. 2, 2003. @inproceedings{mandalakis_loss_2003, title = {Loss Processes of PCBs in the subtropical atmosphere: Study of PCB-OH radical reactions in eastern Mediterranean}, author = {M Mandalakis and E G Stephanou}, year = {2003}, date = {2003-01-01}, booktitle = {Organohalogen Compounds}, volume = {60-65}, pages = {2}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Mandalakis, M; Gustafsson, Ö Journal of Chromatography A, 996 (1-2), pp. 163–172, 2003, ISSN: 00219673, (Publisher: Elsevier). @article{mandalakis_optimization_2003, title = {Optimization of a preparative capillary gas chromatography-mass spectrometry system for the isolation and harvesting of individual polycyclic aromatic hydrocarbons}, author = {M Mandalakis and Ö Gustafsson}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038021269&doi=10.1016%2fS0021-9673%2803%2900612-5&partnerID=40&md5=e062f00b78a8f49e937856db9a1d8a87}, doi = {10.1016/S0021-9673(03)00612-5}, issn = {00219673}, year = {2003}, date = {2003-01-01}, journal = {Journal of Chromatography A}, volume = {996}, number = {1-2}, pages = {163--172}, abstract = {Operation parameters of a preparative capillary gas chromatography (pcGC) system were optimized to facilitate clean and efficient harvesting of individual polycyclic aromatic hydrocarbons (PAHs) for subsequent compound-specific radiocarbon analysis. For PAHs, the recommended optimized settings of the specially-designed pcGC cooled injection system (CIS) and preparative fraction collector (PFC) are: 5 s CIS solvent venting time, deactivation of CIS "stop flow" injection mode, autoinjector "fast injection" mode, 60 s CIS splitless time, 340°C PFC switch temperature, and 30°C (ambient) trapping temperature. These optimized conditions yielded highly reproducible, pure, and efficient pcGC harvesting of six PAHs with mass recoveries of 90-100% and purity of the isolates of 97-100%. © 2003 Elsevier Science B.V. All rights reserved.}, note = {Publisher: Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } Operation parameters of a preparative capillary gas chromatography (pcGC) system were optimized to facilitate clean and efficient harvesting of individual polycyclic aromatic hydrocarbons (PAHs) for subsequent compound-specific radiocarbon analysis. For PAHs, the recommended optimized settings of the specially-designed pcGC cooled injection system (CIS) and preparative fraction collector (PFC) are: 5 s CIS solvent venting time, deactivation of CIS "stop flow" injection mode, autoinjector "fast injection" mode, 60 s CIS splitless time, 340°C PFC switch temperature, and 30°C (ambient) trapping temperature. These optimized conditions yielded highly reproducible, pure, and efficient pcGC harvesting of six PAHs with mass recoveries of 90-100% and purity of the isolates of 97-100%. © 2003 Elsevier Science B.V. All rights reserved. |
Mandalakis, M; Stephanou, E G Chimia, 57 (9), pp. 505–508, 2003, ISSN: 00094293, (Publisher: Swiss Chemical Society). @article{mandalakis_high-resolution_2003, title = {High-resolution gas chromatographytandem mass spectrometry: A sensitive analytical technique suitable for the study of atmospheric processes of polychlorinated biphenyls and dibenzo-p-dioxins/furans}, author = {M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142120836&doi=10.2533%2f000942903777678984&partnerID=40&md5=4b93582001ea9a5083275dafbcce3443}, doi = {10.2533/000942903777678984}, issn = {00094293}, year = {2003}, date = {2003-01-01}, journal = {Chimia}, volume = {57}, number = {9}, pages = {505--508}, abstract = {The trace-level environmental determination of polychlorinated biphenyls (PCBs) and 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) requires the use of delicate fractionation and analytical techniques such as high-resolution gas chromatography coupled with high-resolution mass spectrometry. The analytical requirements are even higher if atmospheric physicochemical processes of these persistent organic compounds (POPs) are to be studied in remote areas, where concentrations are very low. The optimization of a fractionation method, and of the high-resolution gas chromatography/ion trap tandem mass spectrometry system instrumental parameters enabled us to establish the optimum conditions for the determination of atmospheric PCBs and PCDD/Fs at the low pg or even fg m-3 level. By using this analytical procedure, we accomplished the reliable determination of ca. 54 PCBs and 17 PCDD/Fs individual congeners, of different chlorination level, in the gas and particulate phase of atmospheric aerosol samples collected from the Eastern Mediterranean basin. Furthermore, we were also able to study the atmospheric physicochemical and loss processes of PCBs, such as gas-particle partitioning, wet and dry deposition, and PCBs reaction with hydroxyl radicals.}, note = {Publisher: Swiss Chemical Society}, keywords = {}, pubstate = {published}, tppubtype = {article} } The trace-level environmental determination of polychlorinated biphenyls (PCBs) and 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) requires the use of delicate fractionation and analytical techniques such as high-resolution gas chromatography coupled with high-resolution mass spectrometry. The analytical requirements are even higher if atmospheric physicochemical processes of these persistent organic compounds (POPs) are to be studied in remote areas, where concentrations are very low. The optimization of a fractionation method, and of the high-resolution gas chromatography/ion trap tandem mass spectrometry system instrumental parameters enabled us to establish the optimum conditions for the determination of atmospheric PCBs and PCDD/Fs at the low pg or even fg m-3 level. By using this analytical procedure, we accomplished the reliable determination of ca. 54 PCBs and 17 PCDD/Fs individual congeners, of different chlorination level, in the gas and particulate phase of atmospheric aerosol samples collected from the Eastern Mediterranean basin. Furthermore, we were also able to study the atmospheric physicochemical and loss processes of PCBs, such as gas-particle partitioning, wet and dry deposition, and PCBs reaction with hydroxyl radicals. |
Mandalakis, M; Berresheim, H; Stephanou, E G Direct evidence for destruction of polychlorobiphenyls by OH radicals in the subtropical troposphere Journal Article Environmental Science and Technology, 37 (3), pp. 542–547, 2003, ISSN: 0013936X. @article{mandalakis_direct_2003, title = {Direct evidence for destruction of polychlorobiphenyls by OH radicals in the subtropical troposphere}, author = {M Mandalakis and H Berresheim and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346668318&doi=10.1021%2fes020163i&partnerID=40&md5=cc89166d5dfc3f872f49f7a04a15e1bf}, doi = {10.1021/es020163i}, issn = {0013936X}, year = {2003}, date = {2003-01-01}, journal = {Environmental Science and Technology}, volume = {37}, number = {3}, pages = {542--547}, abstract = {Although laboratory studies have indicated that OH radicals readily oxidize polychorobiphenyls (PCBs) in the gas-phase, this mechanism has never been positively demonstrated under real atmospheric conditions. By applying elaborated sampling and analytical techniques we achieved for the first time simultaneously a field study of the diurnal atmospheric cycle of OH radical and PCBs in a remote site of eastern Mediterranean. In all cases, the concentration of ΣPCB (sum of 27 congeners) showed a characteristic depletion during daytime, while the concentration of OH radicals was at the maximum levels. By assuming that the depletion of PCBs was caused solely by the destruction from OH radicals, PCB-OH rate constants (KOH) of different PCB congeners were determined from field data by applying the relative rate method. Our field-determined KOH values were notably coherent with those previously measured in laboratory experiments. In all measurement periods, the KOH values consistently decreased in sequence for those compounds showing an increasing degree of chlorination on the biphenyl group. Bytaking into account KOH values and latitude-dependent concentration of OH radicals, it was estimated that, near to tropical and subtropical regions, the atmospheric lifetimes of PCBs 8 and 110 should be substantially low (10 and 20 days, respectively). A significant fraction of PCBs should be destroyed during their residence over tropical/subtropical regions, due to the intensive destruction by OH.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Although laboratory studies have indicated that OH radicals readily oxidize polychorobiphenyls (PCBs) in the gas-phase, this mechanism has never been positively demonstrated under real atmospheric conditions. By applying elaborated sampling and analytical techniques we achieved for the first time simultaneously a field study of the diurnal atmospheric cycle of OH radical and PCBs in a remote site of eastern Mediterranean. In all cases, the concentration of ΣPCB (sum of 27 congeners) showed a characteristic depletion during daytime, while the concentration of OH radicals was at the maximum levels. By assuming that the depletion of PCBs was caused solely by the destruction from OH radicals, PCB-OH rate constants (KOH) of different PCB congeners were determined from field data by applying the relative rate method. Our field-determined KOH values were notably coherent with those previously measured in laboratory experiments. In all measurement periods, the KOH values consistently decreased in sequence for those compounds showing an increasing degree of chlorination on the biphenyl group. Bytaking into account KOH values and latitude-dependent concentration of OH radicals, it was estimated that, near to tropical and subtropical regions, the atmospheric lifetimes of PCBs 8 and 110 should be substantially low (10 and 20 days, respectively). A significant fraction of PCBs should be destroyed during their residence over tropical/subtropical regions, due to the intensive destruction by OH. |
Stephanou, E G; Mandalakis, M; Apostolaki, M Transport and Atmospheric Processes PCBs in the subtropical atmosphere of Eastern Mediterranean Inproceedings Goldschmidt Conference Abstracts, pp. 18, 447, 2003. @inproceedings{stephanou_transport_2003, title = {Transport and Atmospheric Processes PCBs in the subtropical atmosphere of Eastern Mediterranean}, author = {E G Stephanou and M Mandalakis and M Apostolaki}, year = {2003}, date = {2003-01-01}, booktitle = {Goldschmidt Conference Abstracts}, volume = {67}, pages = {18, 447}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2002 |
Mandalakis, M; Tsapakis, M; Tsoga, A; Stephanou, E G Gas-particle concentrations and distribution of aliphatic hydrocarbons, PAHs, PCBs and PCDD/Fs in the atmosphere of Athens (Greece) Journal Article Atmospheric Environment, 36 (25), pp. 4023–4035, 2002, ISSN: 13522310. @article{mandalakis_gas-particle_2002, title = {Gas-particle concentrations and distribution of aliphatic hydrocarbons, PAHs, PCBs and PCDD/Fs in the atmosphere of Athens (Greece)}, author = {M Mandalakis and M Tsapakis and A Tsoga and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036721043&doi=10.1016%2fS1352-2310%2802%2900362-X&partnerID=40&md5=161204708dab3e6a7e4e7908d8e4d22d}, doi = {10.1016/S1352-2310(02)00362-X}, issn = {13522310}, year = {2002}, date = {2002-01-01}, journal = {Atmospheric Environment}, volume = {36}, number = {25}, pages = {4023--4035}, abstract = {Air samples were collected at the urban center, a background site, and the adjacent coastal area of the metropolitan area of Athens during July 2000. Gas and particle phase concentrations of aliphatic hydrocarbons, α,β-hopanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were identified and measured. Total concentrations of aliphatic hydrocarbons, ranged between 943.0ngm-3 (urban site) and 947.1ngm-3 (coastal area) in the gas and from 141.8ngm-3 (coastal site) up to 469.0ngm-3 (urban center) in the particulate phase. The total concentration of α,β-hopanes (12 homologues) in the urban area was ca. 0.2ngm-3 in the gas and 1.0ngm-3 in the particulate phase. Total PAH concentrations (∑PAHs of 20 members) ranged from 3.5ngm-3 (background site) to 26.0ngm-3 (urban center) in the gas and from 1.3ngm-3 (coastal area) up to 5.0ngm-3 (urban center) in the particulate phase. The total concentration of PCBs (∑PCBs of 38 congeners) in the gas plus the particulate phase of the atmosphere ranged from 80.5pgm-3 (background site) up to 348.6pgm-3 (urban center) and the corresponding concentration of PCDD/Fs ranged from 166.6fgm-3 (background site) up to 701.5fgm-3 (urban center), respectively. Gas-particle partition coefficients Kp of n-alkanes, PAHs, PCBs and PCDD/Fs were well correlated (R2=0.50-0.99) with the sub-cooled liquid vapor pressure PL o. The average slopes mr of logKp versus log PL o for n-alkanes (-0.46) and PCBs (-0.44) were low compared to other urban areas. The corresponding mr values for PAHs (-0.57), PCDDs (-0.78) and PCDFs (-0.75) are comparable to those obtained in other urban areas. Copyright © 2002 Elsevier Science Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Air samples were collected at the urban center, a background site, and the adjacent coastal area of the metropolitan area of Athens during July 2000. Gas and particle phase concentrations of aliphatic hydrocarbons, α,β-hopanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were identified and measured. Total concentrations of aliphatic hydrocarbons, ranged between 943.0ngm-3 (urban site) and 947.1ngm-3 (coastal area) in the gas and from 141.8ngm-3 (coastal site) up to 469.0ngm-3 (urban center) in the particulate phase. The total concentration of α,β-hopanes (12 homologues) in the urban area was ca. 0.2ngm-3 in the gas and 1.0ngm-3 in the particulate phase. Total PAH concentrations (∑PAHs of 20 members) ranged from 3.5ngm-3 (background site) to 26.0ngm-3 (urban center) in the gas and from 1.3ngm-3 (coastal area) up to 5.0ngm-3 (urban center) in the particulate phase. The total concentration of PCBs (∑PCBs of 38 congeners) in the gas plus the particulate phase of the atmosphere ranged from 80.5pgm-3 (background site) up to 348.6pgm-3 (urban center) and the corresponding concentration of PCDD/Fs ranged from 166.6fgm-3 (background site) up to 701.5fgm-3 (urban center), respectively. Gas-particle partition coefficients Kp of n-alkanes, PAHs, PCBs and PCDD/Fs were well correlated (R2=0.50-0.99) with the sub-cooled liquid vapor pressure PL o. The average slopes mr of logKp versus log PL o for n-alkanes (-0.46) and PCBs (-0.44) were low compared to other urban areas. The corresponding mr values for PAHs (-0.57), PCDDs (-0.78) and PCDFs (-0.75) are comparable to those obtained in other urban areas. Copyright © 2002 Elsevier Science Ltd. |
Mandalakis, M; Stephanou, E G Environmental Toxicology and Chemistry, 21 (11), pp. 2270–2275, 2002, ISSN: 07307268. @article{mandalakis_polychlorinated_2002, title = {Polychlorinated biphenyls associated with fine particles (PM2.5) in the urban environment of Chile: Concentration levels, and sampling volatilization losses}, author = {M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036837688&partnerID=40&md5=103f99d2532d3e08bec6f200b9fb9303}, issn = {07307268}, year = {2002}, date = {2002-01-01}, journal = {Environmental Toxicology and Chemistry}, volume = {21}, number = {11}, pages = {2270--2275}, abstract = {Polychlorinated biphenyls (PCBs) were measured in fine particles (PM2.5, particles smaller than 2.5 μm in diameter) collected in two urban areas of Chile, Santiago and Temuco, during August and October 1998. A diffusion denuder sampling system was used for the collection of 19 samples. The concentrations of total PCBs (47 congeners) ranged from 672 to 1,790 pg/m3 in the city of Temuco and from 1,159 to 2,750 pg/m3 in Santiago. These concentrations are moderately higher than those observed in other urban areas around the world. High amounts of PCBs may volatilize from fine particles during aerosols sampling using conventional high-volume samplers. Average volatilization losses, determined by the diffusion denuder system, varied between 54 and 97%, showing a strong dependence on partial pressure of individual PCB congeners and air temperature. Overall, our results suggest that measurements of PCBs in the particulate phase of the atmosphere, by using conventional high-volume samplers, might be significantly underestimated because of volatilization losses. The underestimation of PCB and other toxic semivolatile organic compound (SOC) levels associated with fine particles in the urban environment may have consequences to the estimation of health risk posed by inhalation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polychlorinated biphenyls (PCBs) were measured in fine particles (PM2.5, particles smaller than 2.5 μm in diameter) collected in two urban areas of Chile, Santiago and Temuco, during August and October 1998. A diffusion denuder sampling system was used for the collection of 19 samples. The concentrations of total PCBs (47 congeners) ranged from 672 to 1,790 pg/m3 in the city of Temuco and from 1,159 to 2,750 pg/m3 in Santiago. These concentrations are moderately higher than those observed in other urban areas around the world. High amounts of PCBs may volatilize from fine particles during aerosols sampling using conventional high-volume samplers. Average volatilization losses, determined by the diffusion denuder system, varied between 54 and 97%, showing a strong dependence on partial pressure of individual PCB congeners and air temperature. Overall, our results suggest that measurements of PCBs in the particulate phase of the atmosphere, by using conventional high-volume samplers, might be significantly underestimated because of volatilization losses. The underestimation of PCB and other toxic semivolatile organic compound (SOC) levels associated with fine particles in the urban environment may have consequences to the estimation of health risk posed by inhalation. |
Mandalakis, M; Stephanou, E G Study of atmospheric PCB concentrations over the eastern Mediterranean Sea Journal Article Journal of Geophysical Research: Atmospheres, 107 (D23), 2002, ISSN: 2169897X, (Publisher: Blackwell Publishing Ltd). @article{mandalakis_study_2002, title = {Study of atmospheric PCB concentrations over the eastern Mediterranean Sea}, author = {M Mandalakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-2542452603&doi=10.1029%2f2001JD001566&partnerID=40&md5=c9307efd806bc8c8189a8992004e2a39}, doi = {10.1029/2001JD001566}, issn = {2169897X}, year = {2002}, date = {2002-01-01}, journal = {Journal of Geophysical Research: Atmospheres}, volume = {107}, number = {D23}, abstract = {Air samples were collected between April 1999 and March 2001 at a background marine site in the eastern Mediterranean Sea and analyzed for polychlorinated biphenyls (PCBs). The average concentrations of total PCB congeners (∑PCBs) in the gas and particulate phases of the atmosphere were 68.1 ± 28.8 and 2.3 ± 1.8 pg/m3, respectively. The lack of seasonal variation for the atmospheric concentration of individual congeners and ∑PCBs and the shallow slopes obtained from the Clausius-Clapeyron (CC) plots for several PCB congeners indicated that long-range transport is the main factor controlling the atmospheric levels of PCBs in this area. Most of the episodes with elevated concentrations of ∑PCBs concurred with air transport from western and central Europe. This observation was mostly attributed to the predominance of N-NW winds in eastern Mediterranean. The wind speed apparently did not affect the atmospheric concentration of PCBs. Significant changes observed on the homologue group profile of PCBs were mostly related to the origin of air parcels sampled and during summer were most probably related to the reaction of the lighter congeners with OH radicals. Partitioning of PCBs between gas and particulate phases was well correlated with the subcooled liquid vapor pressure (PLo) for 11 of the 37 samples. The slopes of log Kp versus log PLo ranged between -0.233 and -0.445 and are among the shallowest measured worldwide. This fact may indicate absorption of PCBs in particles covered by a polar film. Copyright 2002 by the American Geophysical Union.}, note = {Publisher: Blackwell Publishing Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Air samples were collected between April 1999 and March 2001 at a background marine site in the eastern Mediterranean Sea and analyzed for polychlorinated biphenyls (PCBs). The average concentrations of total PCB congeners (∑PCBs) in the gas and particulate phases of the atmosphere were 68.1 ± 28.8 and 2.3 ± 1.8 pg/m3, respectively. The lack of seasonal variation for the atmospheric concentration of individual congeners and ∑PCBs and the shallow slopes obtained from the Clausius-Clapeyron (CC) plots for several PCB congeners indicated that long-range transport is the main factor controlling the atmospheric levels of PCBs in this area. Most of the episodes with elevated concentrations of ∑PCBs concurred with air transport from western and central Europe. This observation was mostly attributed to the predominance of N-NW winds in eastern Mediterranean. The wind speed apparently did not affect the atmospheric concentration of PCBs. Significant changes observed on the homologue group profile of PCBs were mostly related to the origin of air parcels sampled and during summer were most probably related to the reaction of the lighter congeners with OH radicals. Partitioning of PCBs between gas and particulate phases was well correlated with the subcooled liquid vapor pressure (PLo) for 11 of the 37 samples. The slopes of log Kp versus log PLo ranged between -0.233 and -0.445 and are among the shallowest measured worldwide. This fact may indicate absorption of PCBs in particles covered by a polar film. Copyright 2002 by the American Geophysical Union. |
Gustafsson, Ö; Axelman, J; Bandh, C; Jönsson, A; Broman, D; Breivik, K; Manö, S; Pacyna, J; Cziudaj, G; Petrick, G; Schulz-Bull, D; Meijer, S; Ockenden, W; Jones, K; Sweetman, A; Mandalakis, M; Tsapakis, M; Stephanou, E G; van Drooge, B; Ribes, S; Torres, C; Grimalt, J Global budget for PCBs provides prediction of their environmental longevities Inproceedings Abstracts of Papers of the American Chemical Society, pp. Part 1–2, ENVR 7, 2002, (Publication Title: Abstracts of Papers of the American Chemical Society Type: Conference Publication Part 1-2, ENVR 7). @inproceedings{gustafsson_global_2002, title = {Global budget for PCBs provides prediction of their environmental longevities}, author = {Ö Gustafsson and J Axelman and C Bandh and A Jönsson and D Broman and K Breivik and S Manö and J Pacyna and G Cziudaj and G Petrick and D Schulz-Bull and S Meijer and W Ockenden and K Jones and A Sweetman and M Mandalakis and M Tsapakis and E G Stephanou and B van Drooge and S Ribes and C Torres and J Grimalt}, year = {2002}, date = {2002-01-01}, booktitle = {Abstracts of Papers of the American Chemical Society}, volume = {224}, pages = {Part 1--2, ENVR 7}, note = {Publication Title: Abstracts of Papers of the American Chemical Society Type: Conference Publication Part 1-2, ENVR 7}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
2001 |
Mandalakis, M; Tsapakis, M; Stephanou, E G Journal of Chromatography A, 925 (1-2), pp. 183–196, 2001, ISSN: 00219673, (Publisher: Elsevier). @article{mandalakis_optimization_2001, title = {Optimization and application of high-resolution gas chromatography with ion trap tandem mass spectrometry to the determination of polychlorinated biphenyls in atmospheric aerosols}, author = {M Mandalakis and M Tsapakis and E G Stephanou}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035800692&doi=10.1016%2fS0021-9673%2801%2901033-0&partnerID=40&md5=bc2efef41df1a986a561509985d9f65b}, doi = {10.1016/S0021-9673(01)01033-0}, issn = {00219673}, year = {2001}, date = {2001-01-01}, journal = {Journal of Chromatography A}, volume = {925}, number = {1-2}, pages = {183--196}, abstract = {Optimization of the Finnigan GCQ ion trap mass spectrometry (ITMS) system and a clean-up procedure were carried out in order to apply high-resolution gas chromatography-tandem mass spectrometry for the analysis of polychlorinated biphenyls (PCBs) in aerosols. Six ITMS operating parameters, including isolation time, excitation voltage, excitation time, 'q' value, ion source temperature and electron energy were adjusted in order to optimize the instrument analytical performance. The adjustment of all parameters substantially increased the sensitivity of ITMS in the MS-MS mode. Changes in isolation time did not particularly affect ITMS sensitivity while ion source temperature had the strongest influence. After optimization, a limit of detection of 600 fg/μl with S/N varying from 8 up to 91 was achieved. The application of the optimized ITMS parameters conjointly with the developed clean-up procedure resulted in method detection limits of 10-20 fg/m3 for the determination of PCBs, in the particulate and gas phase of the atmospheric aerosol of background areas in the Eastern Mediterranean and Sweden. Copyright © 2001 Elsevier Science B.V.}, note = {Publisher: Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } Optimization of the Finnigan GCQ ion trap mass spectrometry (ITMS) system and a clean-up procedure were carried out in order to apply high-resolution gas chromatography-tandem mass spectrometry for the analysis of polychlorinated biphenyls (PCBs) in aerosols. Six ITMS operating parameters, including isolation time, excitation voltage, excitation time, 'q' value, ion source temperature and electron energy were adjusted in order to optimize the instrument analytical performance. The adjustment of all parameters substantially increased the sensitivity of ITMS in the MS-MS mode. Changes in isolation time did not particularly affect ITMS sensitivity while ion source temperature had the strongest influence. After optimization, a limit of detection of 600 fg/μl with S/N varying from 8 up to 91 was achieved. The application of the optimized ITMS parameters conjointly with the developed clean-up procedure resulted in method detection limits of 10-20 fg/m3 for the determination of PCBs, in the particulate and gas phase of the atmospheric aerosol of background areas in the Eastern Mediterranean and Sweden. Copyright © 2001 Elsevier Science B.V. |