Maria Ioanna Tsertou

@article{skliros_unveiling_2024,
title = {Unveiling Emerging Opportunistic Fish Pathogens in Aquaculture: A Comprehensive Seasonal Study of Microbial Composition in Mediterranean Fish Hatcheries},
author = {Dimitrios Skliros and Maria Kostakou and Constantina Kokkari and Maria Ioanna Tsertou and Christina Pavloudi and Haris Zafeiropoulos and Pantelis Katharios and Emmanouil Flemetakis},
url = {https://www.mdpi.com/2076-2607/12/11/2281
https://imbbc.hcmr.gr/wp-content/uploads/2024/11/2024-Skliros-microorganisms-45.pdf},
doi = {10.3390/microorganisms12112281},
issn = {2076-2607},
year = {2024},
date = {2024-11-12},
urldate = {2024-11-12},
journal = {Microorganisms},
volume = {12},
number = {11},
pages = {2281},
abstract = {The importance of microbial communities in fish hatcheries for fish health and welfare has been recognized, with several studies mapping these communities during healthy rearing conditions and disease outbreaks. In this study, we analyzed the bacteriome of the live feeds, such as microalgae, rotifers, and Artemia, used in fish hatcheries that produce Mediterranean species. Our goal was to provide baseline information about their structure, emphasizing in environmental putative fish pathogenic bacteria. We conducted 16S rRNA amplicon Novaseq sequencing for our analysis, and we inferred 46,745 taxonomically annotated ASVs. Results showed that incoming environmental water plays a significant role in the presence of important taxa that constitute presumptive pathogens. Bio-statistical analyses revealed a relatively stable bacteriome among seasonal samplings for every hatchery but a diverse bacteriome between sampling stations and a distinct core bacteriome for each hatchery. Analysis of putative opportunistic fish pathogenic genera revealed some co-occurrence correlation events and a high average relative abundance of Vibrio, Tenacibaculum, and Photobacterium genera in live feeds, reaching a grand mean average of up to 7.3% for the hatchery of the Hellenic Center of Marine Research (HCMR), 12% for Hatchery A, and 11.5% for Hatchery B. Mapping the bacteriome in live feeds is pivotal for understanding the marine environment and distinct aquaculture practices and can guide improvements in hatchery management, enhancing fish health and sustainability in the Mediterranean region.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{tsertou_isolation_2023,
title = {Isolation and characterization of a novel Tenacibaculum species and a corresponding bacteriophage from a Mediterranean fish hatchery: Description of Tenacibaculum larymnensis sp. nov. and Tenacibaculum phage Larrie},
author = {Maria Ioanna Tsertou and Adriana Triga and Stavros Droubogiannis and Constantina Kokkari and Grammatiki Anasi and Pantelis Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/03/2023-Tsertou-FroMicro-13.pdf
https://www.frontiersin.org/articles/10.3389/fmicb.2023.1078669/full},
doi = {10.3389/fmicb.2023.1078669},
issn = {1664-302X},
year = {2023},
date = {2023-03-07},
urldate = {2023-03-07},
journal = {Frontiers in Microbiology},
volume = {14},
pages = {1078669},
abstract = {Tenacibaculum larymnensis
sp. nov., a novel species of the
Tenacibaculum
genus was isolated from a commercial fish hatchery in Greece. The novel species is phylogenetically close to
T. discolor
and was biochemically and genetically characterized. The genome of
T
.
larymnensis
has 3.66 Mbps length, 31.83% GC content and the genomic analysis demonstrated that it harbors a wide enzymatic repertoire suggestive of increased degrading capacity but also several virulence factors including hemolysins, secretion systems, transporters, siderophores, pili and extracellular proteins. Using the novel strain, a virulent bacteriophage designated as Tenacibaculum phage Larrie was isolated and characterized. Larrie is a novel Siphovirus with relatively large genome, 77.5 kbps with 111 ORFs, a GC content of 33.7% and an exclusively lytic lifestyle. The new phage-host system can serve as an efficient model to study microbial interactions in the aquatic environment which contribute to the nutrient cycling.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{kalatzis_staying_2023,
title = {Staying below the Radar: Unraveling a New Family of Ubiquitous “Cryptic” Non-Tailed Temperate Vibriophages and Implications for Their Bacterial Hosts},
author = {Panos G Kalatzis and Jesper Juel Mauritzen and Caroline Sophie Winther-Have and Slawomir Michniewski and Andrew Millard and Maria Ioanna Tsertou and Pantelis Katharios and Mathias Middelboe},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/02/2023-Kalatzis-IJMolSci-11.pdf
https://www.mdpi.com/1422-0067/24/4/3937},
doi = {10.3390/ijms24043937},
issn = {1422-0067},
year = {2023},
date = {2023-02-17},
urldate = {2023-02-20},
journal = {International Journal of Molecular Sciences},
volume = {24},
number = {4},
pages = {3937},
abstract = {Bacteriophages are the most abundant biological entities in the oceans and play key roles in bacterial activity, diversity and evolution. While extensive research has been conducted on the role of tailed viruses (Class: Caudoviricetes), very little is known about the distribution and functions of the non-tailed viruses (Class: Tectiliviricetes). The recent discovery of the lytic Autolykiviridae family demonstrated the potential importance of this structural lineage, emphasizing the need for further exploration of the role of this group of marine viruses. Here, we report the novel family of temperate phages under the class of Tectiliviricetes, which we propose to name “Asemoviridae” with phage NO16 as a main representative. These phages are widely distributed across geographical regions and isolation sources and found inside the genomes of at least 30 species of Vibrio, in addition to the original V. anguillarum isolation host. Genomic analysis identified dif-like sites, suggesting that NO16 prophages recombine with the bacterial genome based on the XerCD site-specific recombination mechanism. The interactions between the NO16 phage and its V. anguillarum host were linked to cell density and phage–host ratio. High cell density and low phage predation levels were shown to favor the temperate over the lytic lifestyle for NO16 viruses, and their spontaneous induction rate was highly variable between different V. anguillarum lysogenic strains. NO16 prophages coexist with the V. anguillarum host in a mutualistic interaction by rendering fitness properties to the host, such as increased virulence and biofilm formation through lysogenic conversion, likely contributing to their global distribution.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{pavloudi_investigation_2023,
title = {Investigation of systemic granulomatosis in cultured meagre, Argyrosomus regius, using clinical metagenomics},
author = {Christina Pavloudi and Maria Ioanna Tsertou and Efthimia Antonopoulou and Pantelis Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2023/01/2023-Pavloudi-AQUA-pre-print-8.pdf
https://linkinghub.elsevier.com/retrieve/pii/S0044848623000224},
doi = {10.1016/j.aquaculture.2023.739249},
issn = {00448486},
year = {2023},
date = {2023-01-25},
urldate = {2023-01-25},
journal = {Aquaculture},
volume = {567},
pages = {739249},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{cascarano_epitheliocystis_2022,
title = {Epitheliocystis in Greater Amberjack: Evidence of a Novel Causative Agent, Pathology, Immune Response and Epidemiological Findings},
author = {Maria Chiara Cascarano and Maja Ruetten and Lloyd Vaughan and Maria Ioanna Tsertou and Dimitra Georgopoulou and Kleoniki Keklikoglou and Nikos Papandroulakis and Pantelis Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/05/2022-Cascarano-Microorganisms-20.pdf
https://www.mdpi.com/2076-2607/10/3/627},
doi = {10.3390/microorganisms10030627},
issn = {2076-2607},
year = {2022},
date = {2022-03-01},
urldate = {2022-05-09},
journal = {Microorganisms},
volume = {10},
number = {3},
pages = {627},
abstract = {Epitheliocystis is a fish gill disease caused by a broad range of intracellular bacteria infecting freshwater and marine fish worldwide. Here we report the occurrence and progression of epitheliocystis in greater amberjack reared in Crete (Greece). The disease appears to be caused mainly by a novel Betaproteobacteria belonging to the Candidatus Ichthyocystis genus with a second agent genetically similar to Ca. Parilichlamydia carangidicola coinfecting the gills in some cases. After a first detection of the disease in 2017, we investigated epitheliocystis in the following year’s cohort of greater amberjack juveniles (cohort 2018) transferred from inland tanks to the same cage farm in the open sea where the first outbreak was detected. This cohort was monitored for over a year together with stocks of gilthead seabream and meagre co-farmed in the same area. Our observations showed that epitheliocystis could be detected in greater amberjack gills as early as a month following the transfer to sea cages, with ionocytes at the base of the gill lamellae being initially infected. Cyst formation appears to trigger a proliferative response, leading to the fusion of lamellae, impairment of gill functions and subsequently to mortality. Lesions are characterized by infiltration of immune cells, indicating activation of the innate immune response. At later stages of the outbreak, cysts were no longer found in ionocytes but were observed in mucocytes at the trailing edge of the filament. Whole cysts appeared finally to be expelled from infected mucocytes directly into the water, which might constitute a novel means of dispersion of the infectious agents. Molecular screening indicates that meagre is not affected by this disease and confirms the presence of previously described epitheliocystis agents, Ca. Ichthyocystis sparus, Ca. Ichthyocystis hellenicum and Ca. Similichlamydia spp., in gilthead seabream. Prevalence data show that the bacteria persist in both gilthead seabream and greater amberjack cohorts after first infection.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{tsertou_comparative_2022,
title = {Comparative study of Chronic Ulcerative Dermatopathy in cultured meagre, Argyrosomus regius},
author = {M I Tsertou and N Papandroulakis and K Keklikoglou and I Kalantzi and M Tsapakis and A Tsalafouta and M Pavlidis and E Antonopoulou and P Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/05/2022-Tsertou-AQUA-pre-print-34.pdf
https://linkinghub.elsevier.com/retrieve/pii/S0044848622004173},
doi = {10.1016/j.aquaculture.2022.738301},
issn = {00448486},
year = {2022},
date = {2022-01-01},
urldate = {2022-05-09},
journal = {Aquaculture},
volume = {556},
pages = {738301},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{droubogiannis_vibrio_2022,
title = {Vibrio Phage Artemius, a Novel Phage Infecting Vibrio alginolyticus},
author = {Stavros Droubogiannis and Lydia Pavlidi and Maria Ioanna Tsertou and Constantina Kokkari and Dimitrios Skliros and Emmanouil Flemetakis and Pantelis Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/07/2022-Droubogiannis-pathogen-54.pdf
https://www.mdpi.com/2076-0817/11/8/848},
doi = {10.3390/pathogens11080848},
issn = {2076-0817},
year = {2022},
date = {2022-01-01},
urldate = {2022-07-29},
journal = {Pathogens},
volume = {11},
number = {8},
pages = {848},
abstract = {Vibrio alginolyticus is an important pathogen of marine animals and has been the target of phage therapy applications in marine aquaculture for many years. Here, we report the isolation and partial characterization of a novel species of the Siphoviridae family, the Vibrio phage Artemius. The novel phage was species-specific and could only infect strains of V. alginolyticus. It could efficiently reduce the growth of the host bacterium at various multiplicities of infection as assessed by an in vitro lysis assay. It had a genome length of 43,349 base pairs. The complete genome has double-stranded DNA with a G + C content of 43.61%. In total, 57 ORFs were identified, of which 19 were assigned a predicted function. A genomic analysis indicated that Vibrio phage Artemius is lytic and does not harbor genes encoding toxins and antibiotic resistance determinants.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@incollection{tsertou_chronic_2022,
title = {Chronic diseases of the lateral line organ in fish},
author = {Maria Ioanna Tsertou and Efthimia Antonopoulou and Pantelis Katharios},
url = {https://imbbc.hcmr.gr/wp-content/uploads/2022/10/2022-Tsertou-EUD-preprint-67-1.pdf
https://linkinghub.elsevier.com/retrieve/pii/B9780128122112000640},
doi = {10.1016/B978-0-12-812211-2.00064-0},
isbn = {9780128122112},
year = {2022},
date = {2022-01-01},
urldate = {2022-10-12},
booktitle = {Aquaculture Pathophysiology},
pages = {721--725},
publisher = {Elsevier},
keywords = {},
pubstate = {published},
tppubtype = {incollection}
}

@article{tsertou_effect_2020,
title = {The effect of dietary vitamin D3, minerals (Ca, P) and plant-protein sources in the development of systemic granulomatosis in meagre (Argyrosomus regius, Asso, 1801)},
author = {M I Tsertou and S Chatzifotis and R Fontanillas and E Cotou and E Fountoulaki and E Antonopoulou and P Katharios},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0044848619326626},
doi = {10.1016/j.aquaculture.2020.735052},
issn = {00448486},
year = {2020},
date = {2020-05-01},
urldate = {2020-08-31},
journal = {Aquaculture},
volume = {521},
pages = {735052},
abstract = {Systemic Granulomatosis (SG) affects the majority of cultured meagre (Argyrosomus regius). This pathological condition, whose aetiology is still not known, is identified by multiple granulomas in a variety of organs that become calcified and necrotic with time. The available evidence supports the hypothesis that SG is a metabolic disorder associated with nutritional imbalances, and the present study examined the role of dietary vitamin D3, minerals (Ca, P) and plant-protein sources in the development of the disease. The use of plant-protein in the diet formulation exacerbated the progression of SG, while vitamin D3 did not prevent its occurrence. On the other hand, the severity of SG was improved by increasing the P content in the feed. However, the exact irritant that causes this inflammatory response in meagre is still unknown and more research needs to examine other nutritional factors.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{katharios_native_2020,
title = {Native parasite affecting an introduced host in aquaculture: cardiac henneguyosis in the red seabream Pagrus major Temminck & Schlegel (Perciformes: Sparidae) caused by Henneguya aegea n. sp. (Myxosporea: Myxobolidae)},
author = {Pantelis Katharios and Panos Varvarigos and Kleoniki Keklikoglou and Maja Ruetten and Jerry Sojan and Morgina Akter and Maria Chiara Cascarano and Maria Ioanna Tsertou and Constantina Kokkari},
url = {https://doi.org/10.1186/s13071-020-3888-7},
doi = {10.1186/s13071-020-3888-7},
issn = {17563305},
year = {2020},
date = {2020-01-01},
journal = {Parasites & Vectors},
volume = {13},
number = {1},
pages = {27},
abstract = {BACKGROUND: Henneguya Thélohan, 1892 (Myxobolidae) is one of the most species-rich genera of myxosporean parasites infecting fish. Although common in nature, there are few reports of these parasites causing important disease in aquaculture. In this paper, we describe a new species of Henneguya infecting Pagrus major (Temminck & Schlegel), a fish host introduced to the Mediterranean Sea from Japan in the late 1980s. RESULTS: Large plasmodia of the parasite were found in the bulbus arteriosus and in the ventricle of the infected fish. Spores were found mainly in the kidney and heart and were accompanied by melanized macrophages or vascular intimal proliferation mixed with a mild non-suppurative response, respectively. Comparisons of morphometric data for spore and polar capsule length and width, suggest a unique combination of features in the newly described species. Molecular analysis, based on 18S rDNA sequence of the parasite, followed by phylogenetic analysis, indicated that the parasite described here is a novel species of Henneguya, clustered with the marine congeneric species. CONCLUSIONS: Henneguya aegea n. sp. infects in aquaculture P. major, a host introduced as eggs to the Mediterranean from Japan. Despite the high host specificity of the myxobolid parasites, H. aegea n. sp. seems to be able to use P. major as a host and propagate successfully, causing morbidity and mortality. This could result in spillback of the new species from high density cultured non-native P. major to native fish hosts.},
note = {ISBN: 1307102038887
Publisher: BioMed Central},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{tsertou_aetiology_2018,
title = {The aetiology of systemic granulomatosis in meagre (Argyrosomus regius): The “Nocardia” hypothesis},
author = {M I Tsertou and M Smyrli and C Kokkari and E Antonopoulou and P Katharios},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052467668&doi=10.1016%2fj.aqrep.2018.08.002&partnerID=40&md5=625a13223330d31956144851287ee794},
doi = {10.1016/j.aqrep.2018.08.002},
issn = {23525134},
year = {2018},
date = {2018-01-01},
journal = {Aquaculture Reports},
volume = {12},
pages = {5--11},
abstract = {One of the most important bottlenecks of meagre (Argyrosomus regius) production is Systemic Granulomatosis (SG), a pathological condition affecting the majority of farmed populations. The aetiology of the disease, which is characterized by multiple granulomas in all soft tissues, is unknown; however, two hypotheses have been raised. The first is that it may be a metabolic disorder similar to systemic granulomas observed in other cultured fishes. The second hypothesis is that it is caused by bacterial pathogens, most likely Nocardia spp. (i.e. nocardiosis). The aim of this study was to test the bacterial pathogen hypothesis as the aetiological factor of SG. Meagre from various locations of Greece were sampled and examined using microbiological, molecular and histological techniques. The prevalence of granulomas in fish was 100% and was not correlated to an infectious agent, whereas nocardiosis was found in a single incidence (prevalence: 1.3%). The results suggest that nocardiosis is not the cause of SG, as it is most probably present in a confined geographical region in Greece. The metabolic disorder hypothesis for SG is more probable and more research has to been done to conclusively identify the aetiological factor of SG. © 2018 The Authors},
note = {Publisher: Elsevier B.V.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{andree_diplectanum_2016,
title = {Diplectanum sciaenae (Van Beneden & Hesse, 1863) (Monogenea) infecting meagre, Argyrosomus regius (Asso, 1801) broodstock in Catalonia, Spain. A case report},
author = {K B Andree and A Roque and N Duncan and E Gisbert and A Estevez and M I Tsertou and P Katharios},
url = {https://doi.org/10.1016/j.vprsr.2016.02.006},
doi = {10.1016/j.vprsr.2016.02.006},
year = {2016},
date = {2016-01-01},
journal = {Veterinary Parasitology: Regional Studies and Reports},
volume = {1-2},
pages = {75--79},
abstract = {Recurrent infection of captive meagre, Argyrosomus regius, by a monogenean parasite has been observed in the broodstock facilities of Institut de Recerca i Tecnologia Agroalimentàries (IRTA) in Catalonia, Spain, between 2008 and 2015. Following handling procedures related with hormonal treatment for spawning induction, one fish died. Post-mortem examination and detailed microscopical examination using light microscopy, SEM, and histology revealed intense infection by Diplectanum sciaenae (Monogenea, Diplectanidae) which caused noteworthy gill pathology. In the present study, we provide detailed description of the parasite and the pathology caused to its host. This is the first report associating this parasite with disease and mortality in farmed meagre.},
note = {Publisher: Elsevier B.V.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}