Percorrer por autor "Kotoulas, Georgios"
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- Comparative analysis and characterization of expressed sequence tags in gilthead sea bream (Sparus aurata) liver and embryosPublication . Sarropoulou, Elena; Power, Deborah; Magoulas, Antonio; Geisler, Robert; Kotoulas, GeorgiosThe gilthead sea bream (Sparus aurata) is one of the main European aquaculture products and a prospective model species for the Sparidae, which includes several other commercially important species. Future selective breeding of aquaculture stocks will be heavily underpinned by molecular genetic techniques, especially by marker-assisted selection (MAS). Gene marker resources in marine fish species, however, lag behind those of other agricultural animals, and only scanty information exists about the genetic source of phenotypic variation and the identity of quantitative trait loci (QTL). In order to develop molecular resources in gilthead sea bream, complementary DNA libraries were constructed from liver and mixed embryo and larval stages by unidirectional cloning. A long-read expressed sequence tag (EST) database was generated, containing 1394 cDNA clones representing 852 unique cDNA sequence-reads. Tissue-specific patterns of gene expression were determined when grouped using the proposal for characterizing cellular component put forward by the Gene Ontology consortium. Transcripts encoding cytoskeletal proteins were most abundant in the embryonic/larval library, while the most abundant transcripts in the liver library encoded secreted and extracellular proteins. Of both libraries, 505 clones were sequenced in both orientations (5Vand 3Vend sequencing), where 226 clones were determined as full-length sequence reads. Cluster analysis of 3Vend-sequenced clones from both libraries revealed that alternative polyadenylation signals were utilized, although no evidence of alternative splicing was found. We report for the first time for gilthead sea bream or any sparid a transcriptional analysis of two tissues and briefly consider the utility of ESTs for characterizing tissue-specific expression profiles. D 2004 Elsevier B.V. All rights reserved.
- European marine omics biodiversity observation network: a strategic outline for the implementation of omics approaches in ocean observationPublication . Santi, Ioulia; Beluche, Odette; Beraud, Mélanie; Buttigieg, Pier Luigi; Casotti, Raffaella; Cox, Cymon J.; Cunliffe, Michael; Davies, Neil; de Cerio, Oihane Diaz; Exter, Katrina; Kervella, Anne Emmanuelle; Kotoulas, Georgios; Lagaisse, Rune; Laroquette, Arnaud; Louro, Bruno; Not, Fabrice; Obst, Matthias; Pavloudi, Christina; Poulain, Julie; Præbel, Kim; Vanaverbeke, Jan; Pade, NicolasMarine ecosystems, ranging from coastal seas and wetlands to the open ocean, accommodate a wealth of biological diversity from small microorganisms to large mammals. This biodiversity and its associated ecosystem function occurs across complex spatial and temporal scales and is not yet fully understood. Given the wide range of external pressures on the marine environment, this knowledge is crucial for enabling effective conservation measures and defining the limits of sustainable use. The development and application of omics-based approaches to biodiversity research has helped overcome hurdles, such as allowing the previously hidden community of microbial life to be identified, thereby enabling a holistic view of an entire ecosystem's biodiversity and functioning. The potential of omics-based approaches for marine ecosystems observation is enormous and their added value to ecosystem monitoring, management, and conservation is widely acknowledged. Despite these encouraging prospects, most omics-based studies are short-termed and typically cover only small spatial scales which therefore fail to include the full spatio-temporal complexity and dynamics of the system. To date, few attempts have been made to establish standardised, coordinated, broad scaled, and long-term omics observation networks. Here we outline the creation of an omics-based marine observation network at the European scale, the European Marine Omics Biodiversity Observation Network (EMO BON). We illustrate how linking multiple existing individual observation efforts increases the observational power in large-scale assessments of status and change in biodiversity in the oceans. Such large-scale observation efforts have the added value of cross-border cooperation, are characterised by shared costs through economies of scale, and produce structured, comparable data. The key components required to compile reference environmental datasets and how these should be linked are major challenges that we address.
- Gene expression profiling of gilthead sea bream during early development and detection of stress-related genes by the application of cDNA microarray technologyPublication . Sarropoulou, Elena; Kotoulas, Georgios; Power, Deborah; Geisler, RobertGene expression profiling of gilthead sea bream during early development and detection of stress-related genes by the application of cDNA microarray technology. Physiol Genomics 23: 182–191, 2005. First published July 26, 2005; doi:10.1152/physiolgenomics.00139.2005.—Large-scale gene expression studies were performed for one of the main European aquaculture species, the gilthead sea bream Sparus auratus L. For this purpose, a cDNA microarray containing 10,176 clones from a cDNA library of mixed embryonic and larval stages was constructed. In addition to its importance for aquaculture, the taxonomic position and the relatively small genome size of sea bream makes it a prospective model for evolutionary biology and comparative genomics. However, so far, no large-scale analysis of gene expression exists for this species. In the present study, gene expression was analyzed in gilthead sea bream during early development, a significant period in the determination of quantitative traits and therefore of considerable interest for aquaculture. Synexpression groups expressed primarily early and late in development were determined and were composed of both known and novel genes. Furthermore, it was possible to identify stress response genes induced by cortisol injections using the cDNA microarray generated. The creation of gene expression profiles for sea bream by microarray hybridization will accelerate identification of candidate genes involved in multifactorial traits and certain regulatory pathways and will also contribute to a better understanding of the genetic background of fish physiology, which may help to improve aquaculture practices.
- A gene-based radiation hybrid map of the gilthead sea bream Sparus aurata refines and exploits conserved synteny with Tetraodon nigroviridisPublication . Sarropoulou, Elena; Franch, Rafaella; Louro, Bruno; Power, Deborah; Bargelloni, Luca; Magoulas, Antonio; Senger, Fabrice; Kotoulas, Georgios; Geisler, RobertBackground: Comparative teleost studies are of great interest since they are important in aquaculture and in evolutionary issues. Comparing genomes of fully sequenced model fish species with those of farmed fish species through comparative mapping offers shortcuts for quantitative trait loci (QTL) detections and for studying genome evolution through the identification of regions of conserved synteny in teleosts. Here a comparative mapping study is presented by radiation hybrid (RH) mapping genes of the gilthead sea bream Sparus aurata, a non-model teleost fish of commercial and evolutionary interest, as it represents the worldwide distributed species-rich family of Sparidae. Results: An additional 74 microsatellite markers and 428 gene-based markers appropriate for comparative mapping studies were mapped on the existing RH map of Sparus aurata. The anchoring of the RH map to the genetic linkage map resulted in 24 groups matching the karyotype of Sparus aurata. Homologous sequences to Tetraodon were identified for 301 of the gene-based markers positioned on the RH map of Sparus aurata. Comparison between Sparus aurata RH groups and Tetraodon chromosomes (karyotype of Tetraodon consists of 21 chromosomes) in this study reveals an unambiguous one-to-one relationship suggesting that three Tetraodon chromosomes correspond to six Sparus aurata radiation hybrid groups. The exploitation of this conserved synteny relationship is furthermore demonstrated by in silico mapping of gilthead sea bream expressed sequence tags (EST) that give a significant similarity hit to Tetraodon. Conclusion: The addition of primarily gene-based markers increased substantially the density of the existing RH map and facilitated comparative analysis. The anchoring of this gene-based radiation hybrid map to the genome maps of model species broadened the pool of candidate genes that mainly control growth, disease resistance, sex determination and reversal, reproduction as well as environmental tolerance in this species, all traits of great importance for QTL mapping and marker assisted selection. Furthermore this comparative mapping approach will facilitate to give insights into chromosome evolution and into the genetic make up of the gilthead sea bream.
- A genetic linkage map of the hermaphrodite teleost fish Sparus aurata L.Publication . Franch, Rafaella; Louro, Bruno; Tsalavouta, Matina; Chatziplis, Dimitris; Tsigenopoulos, C.; Sarropoulou, Elena; Antonello, Jenny; Magoulas, Andonis; Mylonas, Constantinos C.; Babbucci, Massimiliano; Patarnello, T.; Power, Deborah; Kotoulas, Georgios; Bargelloni, LucaThe gilthead sea bream (Sparus aurata L.) is a marine fish of great importance for fisheries and aquaculture. It has also a peculiar sex-determination system, being a protandrous hermaphrodite. Here we report the construction of a first-generation genetic linkage map for S. aurata, based on 204 microsatellite markers. Twenty-six linkage groups (LG) were found. The total map length was 1241.9 cM. The ratio between sex-specific map lengths was 1:1.2 (male:female). Comparison with a preliminary radiation hybrid (RH) map reveals a good concordance, as all markers located in a single LG are located in a single RH group, except for Ad-25 and CId-31. Comparison with the Tetraodon nigroviridis genome revealed a considerable number of evolutionary conserved regions (ECRs) between the two species. The mean size of ECRs was 182 bp (sequence identity 60–90%). Forty-one ECRs have a known chromosomal location in the pufferfish genome. Despite the limited number of anchoring points, significant syntenic relationships were found. The linkage map presented here provides a robust comparative framework for QTL analysis in S. aurata and is a step toward the identification of genetic loci involved both in the determination of economically important traits and in the individual timing of sex reversal.
- Genomic resources for the aquaculture of European sea bassPublication . Volckaert, F.; Batargias, C.; Bonhomme, F.; Canario, Adelino V. M.; Chistiakov, D.; Choudhuri, J. V.; Galibert, F.; Georgoudis, A.; Haley, Chris; Hellemans, Bart; Kuhl, H.; Kotoulas, Georgios; Law, A.; Libertini, A.; Magoulas, A.; McAndrew, B. J.; Reinhardt, Richard; Senger, Fabrice; Souche, E.; Tsigenopoulos, C.; Whitaker, H. A.The BASSMAP consortium, funded by the European Union, has been set up to improve the understanding of the genome of European sea bass (Dicentrarchus labrax). The specific aim is to locate genes of known function on the physical map and to compare specific regions among perciforms. We have produced an F1 cross of outbred sea bass as mapping panel and a Bacterial Artificial Chromosome library (7× redundancy and 165 kb average insert size). End sequencing of the BAC library is in progress and a radiation hybrid panel is under construction.
- metaGOflow: a workflow for the analysis of marine genomic observatories shotgun metagenomics dataPublication . Zafeiropoulos, Haris; Beracochea, Martin; Ninidakis, Stelios; Exter, Katrina; Potirakis, Antonis; De Moro, Gianluca; Richardson, Lorna; Corre, Erwan; Machado, João Paulo; Pafilis, Evangelos; Kotoulas, Georgios; Santi, Ioulia; Finn, Robert D; J. Cox, Cymon; Pavloudi, ChristinaBackground: Genomic Observatories (GOs) are sites of long-term scientific study that undertake regular assessments of the genomic biodiversity. The European Marine Omics Biodiversity Observation Network (EMO BON) is a network of GOs that conduct regular biological community samplings to generate environmental and metagenomic data of microbial communities from designated marine stations around Europe. The development of an effective workflow is essential for the analysis of the EMO BON metagenomic data in a timely and reproducible manner. Findings: Based on the established MGnify resource, we developed metaGOflow. meta GOflow supports the fast inference of taxonomic profiles from GO-derived data based on ribosomal RNA genes and their functional annotation using the raw reads. Thanks to the Research Object Crate packaging, relevant metadata about the sample under study, and the details of the bioinformatics analysis it has been subjected to, are inherited to the data product while its modular implementation allows running the workflow partially. The analysis of 2 EMO BON samples and 1 Tara Oceans sample was performed as a use case. Conclusions: metaGOflow is an efficient and robust workflow that scales to the needs of projects producing big metagenomic data such as EMO BON. It highlights how containerization technologies along with modern workflow languages and metadata package approaches can support the needs of researchers when dealing with ever-increasing volumes of biological data. Despite being initially oriented to address the needs of EMO BON, metaGOflowis a flexible and easy-to-use workflow that can be broadly used for one-sample-at-a-time analysis of shotgun metagenomics data.
- The ocean sampling day consortiumPublication . Kopf, Anna; Bicak, Mesude; Kottmann, Renzo; Schnetzer, Julia; Kostadinov, Ivaylo; Lehmann, Katja; Fernandez-Guerra, Antonio; Jeanthon, Christian; Rahav, Eyal; Ullrich, Matthias; Wichels, Antje; Jones, Scott; Orlic, Sandi; Steinke, Michael; Busch, Julia; Duarte, Bernardo; Caçador, Isabel; ten Hoopen, Petra; Canning-Clode, João; Aguirre-Macedo, Ma L.; Bobrova, Oleksandra; Vezzi, Alessandro; Marteinsson, Viggo; Collin, Rachel; Reynisson, Eyjolfur; Loureiro, Clara M.; Luna, Gian M.; Quero, Grazia M.; Löscher, Carolin R.; Kremp, Anke; Amaral, Valentina; DeLorenzo, Marie E.; Yoshida, Takashi; Øvreås, Lise; Wang, Shiao; Fuhrman, Jed A.; Tolman, Jennifer; LaRoche, Julie; Penna, Antonella; Frischer, Marc; Davis, Timothy; Katherine, Barker; Meyer, Christopher P.; Ogata, Hiroyuki; Conan, Pascal; Todorova, Nadezhda; Alonso, Cecilia; Stambler, Noga; Goodwin, Kelly; Nyhus, Paul A. F.; Yakimov, Michael M.; Santana, Rafael; Baltar, Federico; Bodrossy, Levente; Ingleton, Tim; Van De Kamp, Jodie; Frampton, Dion M.; Ostrowski, Martin; Van Ruth, Paul; Karamfilov, Ventzislav; Malthouse, Paul; Bizsel, Kemal C.; Claus, Simon; Deneudt, Klaas; Pedrotti, Maria L.; Munnik, Kate; Mortelmans, Jonas; Pitois, Sophie; Wallom, David; Salter, Ian; Costa, Rodrigo; Schroeder, Declan C.; Kandil, Mahrous M.; Rodriguez-Ezpeleta, Naiara; Kotoulas, Georgios; Berteaux-Lecellier, Veronique; Cochrane, Guy; Wecker, Patricia; Cariou, Thierry; Cancio, I.; Lauro, Federico M.; Vaulot, Daniel; Bienhold, Christina; Ghazal, Hassan; Chaouni, Bouchra; Essayeh, Soumya; Ettamimi, Sara; Iriberri, Juan; Zaid, El H.; Golyshin, Peter N.; Boukhatem, Noureddine; L’Haridon, Stephane; Martin, Patrick; Bouali, Abderrahim; Chahboune, Rajaa; Barrijal, Said; Timinouni, Mohammed; El Otmani, Fatima; Bennani, Mohamed; Mea, Marianna; Gasol, Josep M.; Jensen, Rachelle M.; Gerdts, Gunnar; Hinks, Jamie; Gebbels, Susan; Rosselli, Riccardo; Jude-Lemeilleur, Florence; De Pascale, Fabio; Bente, Edvardsen; Schiavon, Riccardo; dos Santos, Antonina; Moncheva, Snejana; Villar, Emilie; Pesant, Stéphane; Cataletto, Bruno; Malfatti, Francesca; Polymenakou, Paraskevi; Edirisinghe, Ranjith; Sonnenschein, Eva C.; Silveira, Jorge A. H.; Barbier, Michele; Karlsen, Hans E.; Dzhembekova, Nina; Turk, Valentina; Tinta, Tinkara; Fuller, Wayne J.; Salihoglu, Ilkay; Serakinci, Nedime; Ergoren, Mahmut C.; Bresnan, Eileen; Johnson, Zackary; Ramos, Sandra; Sinigalliano, Christopher D.; Siam, Rania; Gidley, Maribeth L.; Biancalana, Florencia; Zingone, Adriana; O’Gara, Fergal; Danovaro, Roberto; Tsiamis, George; Clark, M. S.; Costa, Ana C.; El Bour, Monia; Martins, Ana M.; Magalhães, Catarina; Collins, R. E.; Poulton, Nicole; Ducluzeau, Anne-Lise; Abdallah, Rehab Z.; Jackson, Stephen; Martinez, Jonathan; Costello, Mark J.; Amaral-Zettler, Linda A.; Gilbert, Jack A.; Davies, Neil; Field, Dawn; Glöckner, Frank O.Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.