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| Registros recuperados: 85 | |
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| Gagnaire, Pierre-alexandre; Lamy, Jean-baptiste; Cornette, Florence; Heurtebise, Serge; Degremont, Lionel; Flahauw, Emilie; Boudry, Pierre; Bierne, Nicolas; Lapegue, Sylvie. |
| The Pacific cupped oyster is genetically subdivided into two sister taxa, Crassostrea gigas and C. angulata, which are in contact in the north-western Pacific. The nature and origin of their genetic and taxonomic differentiation remains controversial due the lack of known reproductive barriers and the high degree of morphologic similarity. In particular, whether the presence of ecological and/or intrinsic isolating mechanisms contributes to species divergence is unknown. The recent co-introduction of both taxa into Europe offers a unique opportunity to test how genetic differentiation is maintained under new environmental and demographic conditions. We generated a pseudo-chromosome assembly of the Pacific oyster genome using a combination of BAC-end... |
| Tipo: Text |
Palavras-chave: Cupped oysters; Genome assembly; Species divergence; Reproductive barriers; Recombination rate. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00455/56622/58337.pdf |
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| Lapegue, Sylvie; Bedier, Edouard; Goyard, Emmanuel; Degremont, Lionel; Baud, Jean-pierre; Gerard, Andre; Goulletquer, Philippe; Boudry, Pierre. |
| Two oyster species are currently present along the French coasts : the indigenous European flat oyster (Ostrea edulis), and the Pacific cupped oyster (Crassostrea gigas), that has been introduced from Japan since the beginning of the 70ies. The flat oyster successively suffered from two protozoan diseases during the 60ies and its production decreased from 20 000 tons/year by that time to 1 500 tons/year nowadays. Consequently, the oyster production is principally (99%) based upon the Pacific oyster species with approximately 150 000 tons/year among which 90% are grown from the natural spat. However, the hatchery production of this species is developing and was estimated to 400 to 800 millions spat in 2002. Moreover, strengthened relationships between... |
| Tipo: Text |
Palavras-chave: Growth; Selection; Genetic breeding; Genetic; Ostrea edulis; Crassostrea gigas; Oysters; Croissance; Sélection; Amélioration génétique; Génétique; Ostrea edulis; Crassostrea gigas; Huîtres. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3491.pdf |
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| Azema, Patrick; Travers, Marie-agnes; De Lorgeril, Julien; Tourbiez, Delphine; Degremont, Lionel. |
| Since 2008, the emergent virus OsHV 1μvar has provoked massive mortality events in Crassostrea gigas spat and juveniles in France. Since 2012, mortality driven by the pathogenic bacteria Vibrio aestuarianus has stricken market sized adults. A hypothesis to explain the sudden increase in mortality observed in France since 2012 is that selective pressure due to recurrent viral infections could have led to a higher susceptibility of adults to Vibrio infection. In our study, two OsHV-1-resistant lines (AS and BS) and their respective controls (AC and BC) were experimentally challenged in the laboratory to determine their level of susceptibility to V. aestuarianus infection. At the juvenile stage, the selected lines exhibited lower mortality (14 and 33%) than... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00299/41054/40215.pdf |
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| Degremont, Lionel; Soletchnik, Patrick; Doner, Anne. |
| 2001 shows how important the "R" and "S" biological families are for experimentation as well as the need to "preserve" these families from mortality during the first year. The "experimental nursing" conditions do not allow the conservation of dozens of families with many members for 6 to 8 months. Precocious characterisation at around 4-5 months enables a first selection of the biological material, as well as a first answer to the "in lab" genetical selection of the families. After the first results in 2001 (Céline de Ambroggi, LCPC, L. Degremont), two "precocious characterisation of mortality" experiments are carried out in 2002 on the divergent lineage of some genetical families (LGP production). Two 15 day long experiments are conducted in la Tremblade... |
| Tipo: Text |
Palavras-chave: Mortalités; Sélection; Physiologie; Genetique; Crassostrea gigas; Huîtres. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/acte-3406.pdf |
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| Degremont, Lionel; Fortin, Adeline; Boudry, Pierre. |
| Dans le cadre du programme MOREST, une première génération d'huître creuse Crassostrea gigas (G1) a été réalisée en 2001 à partir d'un plan de croisement hiérarchisé par les mâles. La caractérisation sur estran de 44 familles de plein-frères réparties en 17 familles de demi-frères a permis d'estimer l'héritabilité de la survie des naissains en période estivale. La valeur obtenue (h2 = 0,81 ± 0,29) indique que la majorité de la variance phénotypique est d'origine génétique. A partir de familles G1 sélectionnées pour les performances de survies, une sélection divergente visant à améliorer ou diminuer la survie du naissain en période estivale a été réalisée en 2002 et constitue la seconde génération (G2). La sélection divergente comprend deux séries de... |
| Tipo: Text |
Palavras-chave: Huître creuse; Crassostrea gigas; Génétique; Sélection; Estran. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00035/14668/11970.pdf |
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| Delaporte, Maryse; Soudant, P; Lambert, C; Jegaden, M; Moal, Jeanne; Pouvreau, Stephane; Degremont, Lionel; Boudry, Pierre; Samain, Jean-francois. |
| Within the framework of a national scientific program named "MORtalites ESTivales de l'huitre creuse Crassostrea gigas" (MOREST), a family-based experiment was developed to study the genetic basis of resistance to summer mortality in the Pacific oyster, Crassostrea gigas. As part of the MOREST project, the second generation of three resistant families and two susceptible families were chosen and pooled into two respective groups: "R" and "S". These two groups of oysters were conditioned for 6 months on two food levels (4% and 12% of oyster soft-tissue dry weight in algal dry weight per day) with a temperature gradient that mimicked the Marennes-Oleron natural cycle during the oyster reproductive period. Oyster mortality remained low for the first two... |
| Tipo: Text |
Palavras-chave: Summer mortality; Reproduction; Reactive oxygen species ROS; Hemocyte parameters; Genetic selection; Crassostrea gigas. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3578.pdf |
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| Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Costil, K. S.; Dubois, Brice; Degremont, Lionel; Bouget, Jean-francois; Martin, Jean-louis; Enriquez-diaz, M.; Faury, Nicole; Le Moine, Olivier; Renault, Tristan; Gagnaire, Beatrice; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois. |
| Field characterization of summer mortality was performed in France in the frame of the Morest project. Natural and hatchery spat were compared between three oyster production areas in France. Regardless of the natural or hatchery origin, oysters died during the reproduction period after temperature reaches 19 degree C. Thus, in southern areas, temperature accelerated gametogenesis of small spat (10mm) as well as adults, and mortality appeared for the two age classes. In contrast, sexual maturation proceeded more slowly in northern where spat mortality was lower compared to 18 months old oysters. However, critical gametogenesis and temperature were not sufficient to induce mortalities, as observed in examples with stable environment. Alternatively sediment... |
| Tipo: Text |
Palavras-chave: Seasonal variation; Oyster culture; Mortality causes; Hatcheries; Gametogenesis; Environmental factors; Crassostrea gigas; Oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3348.pdf |
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| Leprêtre, Maxime; Faury, Nicole; Segarra, Amelie; Claverol, Stéphane; Degremont, Lionel; Palos-ladeiro, Mélissa; Armengaud, Jean; Renault, Tristan; Morga, Benjamin. |
| Massive mortality outbreaks affecting Pacific oysters (Crassostrea gigas) spat/juveniles are often associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted using two contrasted Pacific oyster families for their susceptibility to viral infection. Live oysters were sampled at 12, 26, and 144 h post infection (hpi) to analyze host-pathogen interactions using comparative proteomics. Shotgun proteomics allowed the detection of seven viral proteins in infected oysters, some of them with potential immunomodulatoy functions. Viral proteins were mainly detected in susceptible oysters sampled at 26 hpi, which correlates with the mortality and... |
| Tipo: Text |
Palavras-chave: Proteomics; Interactions; Antiviral response; OsHV-1; Pacific oysters. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00669/78075/80307.pdf |
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| De Lorgeril, Julien; Petton, Bruno; Lucasson, Aude; Perez, Valérie; Stenger, Pierre-louis; Degremont, Lionel; Montagnani, Caroline; Escoubas, Jean Michel; Haffner, Philippe; Allienne, Jean-françois; Leroy, Marc; Lagarde, Franck; Vidal Dupiol, Jeremie; Gueguen, Yannick; Mitta, Guillaume. |
| Background: As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible). Results: We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein... |
| Tipo: Text |
Palavras-chave: Pacific oyster; Oyster disease; Resistance; OsHV-1; Antiviral molecular pathways; Invertebrate immunity. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00602/71369/69811.pdf |
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| Agnew, M. Victoria; Friedman, Carolyn S.; Langdon, Christopher; Divilov, Konstantin; Schoolfield, Blaine; Morga, Benjamin; Degremont, Lionel; Dhar, Arun K.; Kirkland, Peter; Dumbauld, Brett; Burge, Colleen A.. |
| Pacific oysters, Crassostrea gigas, are one of the most productive aquaculture species in the world. However, they are threatened by the spread of Ostreid herpesvirus-1 (OsHV-1) and its microvariants (collectively “µvars”), which cause mass mortalities in all life stages of Pacific oysters globally. Breeding programs have been successful in reducing mortality due to OsHV-1 variants following viral outbreaks; however, an OsHV-1-resistant oyster line does not yet exist in the United States (US), and it is unknown how OsHV-1 µvars will affect US oyster populations compared to the current variant, which is similar to the OsHV-1 reference, found in Tomales Bay, CA. The goals of this study were to investigate the resistance of C. gigas juveniles produced by the... |
| Tipo: Text |
Palavras-chave: OsHV-1; Mu vars; Oyster; Virus; Tolerance; Virulence; QPCR. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00665/77739/79862.pdf |
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| Degremont, Lionel; Maurouard, Elise; Godfrin, Yoann; Travers, Marie-agnes; Morga, Benjamin; Lamy, Jean-baptiste; Benabdelmouna, Abdellah. |
| Depuis 2012, le nombre de cas de mortalités d’huîtres creuses adultes (Crassostrea gigas) rapportés dans le cadre des réseaux de surveillance de l’Ifremer, et dans lesquels la bactérie Vibrio aestuarianus a été isolée, a fortement augmenté. Les objectifs de cette étude étaient (1) d’étudier la sensibilité des huîtres C. gigas à une infection à V. aestuarianus pour des lots diploïdes et triploïdes et (2) déterminer la réponse à la sélection pour une meilleure résistance à V. aestuarianus pour des huîtres C. gigas. Neuf stocks ont été utilisés, répartis en trois niveaux de sélection, chacun étant donc répliqué par trois pontes. Pour chaque stock, un lot diploïde (2n), un lot triploïde (3n_chim) produit par la rétention d’un globule polaire, et trois lots... |
| Tipo: Text |
Palavras-chave: Vibrio aestuarianus; OsHV-1; Sélection; Résistance; Triploïdes; Huître creuse; Crassostrea gigas; Vibrio aestuarianus; OsHV-1; Selective breeding; Disease resistance Pacific oyster; Crassostrea gigas; Triploids. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00404/51530/52140.pdf |
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| Segarra, Amelie; Mauduit, Florian; Faury, Nicole; Trancart, Suzanne; Degremont, Lionel; Tourbiez, Delphine; Haffner, Philippe; Barbosa-solomieu, Valerie; Pepin, Jean-francois; Travers, Marie-agnes; Renault, Tristan. |
| Background: Massive mortality outbreaks affecting Pacific oyster (Crassostrea gigas) spat in various countries have been associated with the detection of a herpesvirus called ostreid herpesvirus type 1 (OsHV-1). However, few studies have been performed to understand and follow viral gene expression, as it has been done in vertebrate herpesviruses. In this work, experimental infection trials of C. gigas spat with OsHV-1 were conducted in order to test the susceptibility of several bi-parental oyster families to this virus and to analyze host-pathogen interactions using in vivo transcriptomic approaches. Results: The divergent response of these oyster families in terms of mortality confirmed that susceptibility to OsHV-1 infection has a significant... |
| Tipo: Text |
Palavras-chave: Interactions; Ostreid herpesvirus 1; Gene expression; Susceptibility; Crassostrea gigas. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00199/31029/29431.pdf |
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| Parizadeh, Leila; Tourbiez, Delphine; Garcia, Celine; Haffner, Philippe; Degremont, Lionel; Le Roux, Frederique; Travers, Marie-agnes. |
| Although vibrios are frequently associated with marine organisms mortality outbreaks, knowledge on their ecology and pathogenicity is sparse, thus limiting disease management and prophylactic strategies. Here, we investigated V. aestuarianus infection onset and progression in the wild, taking advantage of a “claire” pond: a semi‐closed system with limited seawater renewal, theoretically more adapted to disease transmission. We showed a positive association of the bacteria with oysters, which can constitute a reservoir for the bacteria in the winter. Moreover, passage through oysters was found to be necessary for experimental disease reproduction as vibrios shedding from diseased oysters has higher infectivity than from in vitro grown. We next developed an... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00446/55761/57423.pdf |
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| Degremont, Lionel; Boudry, Pierre; Soletchnik, Patrick; Bedier, Edouard; Ropert, Michel; Samain, Jean-francois. |
| Three successive generations were produced between 2001 and 2003 to assess to what extent genetic variability exists for this trait in juvenile oysters Crassostrea gigas. For each generation, two groups were selected for their high ("R" for resistant) and low ("S" for susceptible) survival. Significant differences of mortality were observed during the first year in Rivière d'Auray (RA) (Brittany-France). However, low and similar mortality were observed for both groups, with no significant difference between groups in the first and second generation in this site, where the first summer is the critical sensitive period with a clear age effect. In Baie des Veys (BDV) (Normandie-France), where mortalities usually mainly affect adults, mortality between... |
| Tipo: Text |
Palavras-chave: Genetic variability; Genetic; Summer mortality; Crassostrea gigas; Pacific oysters. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3442.pdf |
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| Delaporte, Maryse; Moal, Jeanne; Soudant, Philippe; Lambert, Christophe; Pouvreau, Stephane; Enriquez, Martha; Degremont, Lionel; Soletchnik, Patrick; Gagnaire, Beatrice; Ropert, Michel. |
| In the frame of MOREST project, a common biological material, resulting of a mixture of different families produced in experimental hatchery, was reared in two different environmental fields : Normandy and Charente. Concomitantly, a pool was conditioned at the Ifremer Argenton hatchery with three different algae levels : 4%, 8% and 12% of algal dry weight per oyster dry weight. During the experiments, five immune parameters were studied in parallel with survival rate and reproductive status (stages and intensity). Site location, seasonal variations and experimental diet level clearly influenced oyster immune parameters. Haemocyte counts were higher for oysters reared in Normandy than those reared in Charente and in hatchery. Granulocyte percentage was... |
| Tipo: Text |
Palavras-chave: Defense mechanisms; Nutrition; Seasonal variations; Physiology; Crassostrea gigas; Pacific oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3500.pdf |
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| Degremont, Lionel; Ledu, Christophe; Maurouard, Elise; Nourry, Max; Benabdelmouna, Abdellah. |
| The effect of ploidy on the mortality of Crassostrea gigas spat caused by the ostreid herpesvirus (OsHV-1) genotype μVar was investigated at five sites along the Atlantic coast in France in 2011. Sibling diploids and triploids were produced using either unselected or selected OsHV-1-resistant oysters. No significant interactions were found between the factors of environment, genotype and ploidy at the endpoint dates. The mean mortality rates at the sites were 62 and 59% for diploids and triploids, respectively, and the two rates were not significantly different. The mean mortality rates were 33 and 32% for sibling diploids and triploids, respectively, when OsHV-1-resistant parents were used, and 91 and 85%, respectively, when unselected parents were used.... |
| Tipo: Text |
Palavras-chave: Diploid; Triploid; Mortality; Crassostrea gigas; Ostreid herpesvirus OsHV-1. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00199/31028/29427.pdf |
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| Degremont, Lionel; Boudry, Pierre; Ropert, Michel; Samain, Jean-francois; Bedier, Edouard; Soletchnik, Patrick. |
| This study investigated the effects of age (first or second summer of life) and environment (three study sites on French coasts) on summer mortality in Crassostrea gigas, using three generations of oysters produced during the Morest project. For each generation, two groups of oysters, selected either as 'resistant' (R) or 'susceptible' (S) to summer mortality at the age of 6 months in Rivière d'Auray (RA, South Brittany), were evaluated. In Ronce (Marennes-Oléron Bay) and RA, R oysters had low mortality during their first and second summers, while mortality was higher during the second summer in Baie des Veys (BDV, Normandy). In RA, S oysters exhibited higher mortality during their first summer than during their second, while the opposite result was found... |
| Tipo: Text |
Palavras-chave: Summer mortality; Age; Environment; Genetic; Crassostrea gigas. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6972.pdf |
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| Degremont, Lionel; Boudry, Pierre; Soletchnik, Patrick; Bedier, Edouard; Ropert, Michel; Samain, Jean-francois. |
| Three successive generations were produced between 2001 and 2003 to assess to what extent genetic variability exists for survival in juvenile oysters Crassostrea gigas. For each generation, two groups were selected for their high ("R" for resistant) and low ("S" for susceptible) survival. Significant differences in mortality were observed during the first year in Riviere d'Auray (RA) (Brittany-France). However, low and similar mortality were observed for both groups, with no significant difference between groups in the first and second generation in this site, where the first summer is the critical, sensitive period with a clear age effect. In Baie des Veys (BDV) (Normandie-France), where mortalities usually mainly affect adults, mortality between groups,... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Spat; Spatial variations; Survival; Rearing; Mollusc culture; Marine molluscs; Environmental factors; Nursery grounds; Mortality causes; Biological age; Aquaculture techniques. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3385.pdf |
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| Registros recuperados: 85 | |
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