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| Registros recuperados: 48 | |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Baud, Jean-pierre; Heurtebise, Serge; Nourry, Max; Renault, Tristan; Cochennec, Nathalie; Zanette, Yvan; Blachier, Philippe. |
| Deuxième volet du programme d'essai d'acclimatation de l'huître américaine Crassostrea virginica, ce rapport présente les actions et les résultats de l'année 1993 qui a été consacrée au suivi des performances comparées de croissance des populations de C. gigas et C. virginica produites en 1992, ceci en trois sites différents: • dans le bassin de Marennes-Oléron en claire et sur estran, à la station IFREMER de Bouin en élevage intensif, au CREAA sur l'Ile d'Oléron en marais extensif. Au terme de cette seconde année d'étude, il est d'ores et déjà possible d'affirmer que que la souche anglaise de C. virginica étudiée ne présente pas de caractéristiques de croissance susceptibles de la rendre compétitive par rapport au témoin Crassostrea gigas et cela d'autant... |
| Tipo: Text |
Palavras-chave: Mollusques; Acclimatation; Crassostrea virginica; Crassostrea gigas; Génétique; Pathologie. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/00077/18846/16419.pdf |
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| Benabdelmouna, Abdellah; Guyader, Tanguy; Ledu, Christophe; Laporte, Philippe; Degremont, Lionel. |
| Depuis son introduction en France, l’huître creuse du Pacifique Crassostrea gigas subit des épisodes répétés de mortalité estivale touchant principalement les juvéniles. A partir de 2008, un nouveau pallier a été franchi et ces épisodes de mortalité estivale se sont accrus en intensité, touchant jusqu’à 90% des lots. Actuellement, ces mortalités touchent l’ensemble des façades maritimes ainsi que plusieurs pays utilisant des naissains d’origine Française. L’ostréiculture Française est basée sur l’utilisation majoritaire de naissains sauvages issus d’un captage naturel (75 à 80%) réalisé au niveau des bassins d’Arcachon et de Marennes Oléron en complément avec l’utilisation de naissains, principalement triploïdes, produits par diverses écloseries privées... |
| Tipo: Text |
Palavras-chave: Huître creuse; Crassostrea gigas; Mortalité; Condition d'élevage; Historique des lots. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00063/17405/14910.pdf |
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| Collet, Bertrand; Boudry, Pierre; Bougrier, Serge; Heurtebise, Serge; Phelipot, Pascal; Ledu, Christophe; Morand, Berenice; Heral, Maurice; Gerard, Andre. |
| A European programme (GENEPHYS) was launched in 1996 to study the genetic basis and variability of physiological characters involved in growth in Crassostrea gigas. This research programme was a prerequisite for any genetic selection programme on physiological functions. Research groups from Ireland, England, Greece and France are involved in this project and participate in genetic analyses (allozymes and microsatellites) and physiological analyses (ecophysiology, enzymology, stress proteins). Ifremer at La Tremblade was responsible for producing the biological material while Ifremer-CREMA (human-influenced marine ecosystems research centre) was responsible for carrying out non-destructive physiological analyses. |
| Tipo: Text |
Palavras-chave: Sélection génétique; Croissance; Crassostrea gias; Génétique. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/acte-3243.pdf |
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| Benabdelmouna, Abdellah; Nadolna, Katarzyna; Ledu, Christophe. |
| Aneuploidy (or alteration of chromosome number) has been frequently described in diploid, triploid and tetraploid C. gigas. In diploid Pacific oysters, aneuploidy affects 1 to 3 chromosomes in up to 35% of the somatic cells and is positively correlated with inferior growth of the animal and thus could be associated with significant economic loss in this major aquaculture species. In polyploid Pacific oysters, aneuploidy was shown to be more heavily frequent and is linked to reversion to lower ploidy levels and is at the origin of aberrant gametes formation. In this context, identification of individual chromosomes involved in aneuploidy events both in somatic and germinal cells would be an important step towards the study of the exact occurrence of this... |
| Tipo: Text |
Palavras-chave: Chromosome; Aneuploidy; Genetic; Crassostrea gigas; Pacific oysters. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/acte-3502.pdf |
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| Suquet, Marc; Malo, Florent; Quere, Claudie; Ledu, Christophe; Le Grand, Jacqueline; Benabdelmouna, Abdellah. |
| Triploidy induction in shellfish aims to obtain faster growth and sterility of reared individuals. Triploid Pacific oysters are most often not totally sterile, but have greatly reduced reproductive capacities compared to those recorded in diploid individuals. The description of gamete output in triploid aquatic animals is most often confined to the assessment of fecundity in females. The present work aims at further describing gamete quality of triploid Pacific oysters and comparing it to values observed in diploid individuals. Diploid and triploid oysters (produced by mating tetraploid males × diploid females) were reared in standard conditions and then transferred to the wild to allow the offspring to attain reproductive maturity. At the end of... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Reproduction; Triploidy; Gamete. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00277/38835/37581.pdf |
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| Benabdelmouna, Abdellah; Saunier, Alice; Ledu, Christophe; Travers, Marie-agnes; Morga, Benjamin. |
| In the context of the abnormal mass mortality of mussels in France since 2014, Flow CytoMetry (FCM) was used in 2015 and 2016 to study the DNA content and cell cycle characteristics of hemic circulating cells collected from 2000 mussels. The mussels were sampled from 12 wild and cultivated blue mussels stocks distributed along the French Atlantic coast from the south Brittany to Pertuis Charentais areas. During these surveys, various genetic abnormalities were frequently detected, and ploidy characteristics revealed contrasting profiles that corresponded to respective contrasting sanitary status, i.e. healthy mussels with high cytogenetic quality (HCQ) versus diseased mussels with low cytogenetic quality (LCQ). In the present work, FCM and hemocytology... |
| Tipo: Text |
Palavras-chave: Mussels; Hemocytes; Flow cytometry; Hemocytology; Cytogenetic quality; Neoplasia. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00455/56623/58443.pdf |
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| Barre, Marc; Naciri, Yamama; Boudry, Pierre; Goyard, Emmanuel; Launey, Sophie; Cochennec, Nathalie; Heurtebise, Serge; Ledu, Christophe; Phelipot, Pascal; Gerard, Andre. |
| The Aquaculture and Pathological Genetics (GAP) laboratory at La Tremblade has been monitoring three populations of European flat oyster since 1985 or 1989 under selection for higher survival rates in the presence of the parasite Bonamia ostrea. One selection cycle (1985 population) or two (1989 populations) were carried out by mass selection by placing the oysters for several years in a highly infested zone, and then harvesting spawns from survivors. |
| Tipo: Text |
Palavras-chave: Huîtres plates; Génétique; Selection génétique; Ostrea edulis. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/acte-3244.pdf |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Noiret, Christophe; Peudenier, Isabelle; Grizel, Henri. |
| For determination of ploidy levels in bivalves, three techniques are now routinely used: karyological determination. microfluorimetry and flow cytometry. This paper proposes an alternative technique which is based on determination of the optical density (OD) of stained nuclei using image analysis. A karyological and image analysis comparative experiment conducted on juveniles of Crassostrea gigas (Thunberg) and Ruditapes philippinarum (Adam & Reeve) is described and highlights the advantages of the image analysis technique. Initially developed on C. gigas and R. philippinarum, the image analysis method was easily extended to other bivalve species and to different developmental stages, as demonstrated by two experiments conducted on Ostrea edulis (L.).... |
| Tipo: Text |
Palavras-chave: Estimation bivalve triploidy; Image analysis; Triploid; Genetic; Crassostrea gigas; Oysters. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/1994/publication-3200.pdf |
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| Gerard, Andre; Naciri, Yamama; Noiret, Christophe; Ledu, Christophe; Peignon, Jean-marie. |
| For the first time, effective treatments using cytochalasin B were developed to induce triploidy in the European clam, Ruditapes decussatus (L.). The percentage of triploid embrios was assessed by karyological or image analysis. Two treatments (O.5 or 1 mg of cytochasin B (CB per ml of dimethylsulfoxide in 1 l of sea water) were applied at different times after fertilization (10 to 25 mn), for two different periods (15 and 20 min). Best results were obtained for a CB concentration of 1 mg/l. When treatment was applied 15 min after fertilization for a 20 min period, 94% and 95% of triploid embryos were obtained in two repeated experiments. At metamorphosis, the treated larvae appeared to be no smaller than the control larvae in all experiments. Thowever, in... |
| Tipo: Text |
Palavras-chave: Genetic; Ruditapes decussatus; Clam; Induced triploidy. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/1994/publication-3208.pdf |
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| Huvet, Arnaud; Gerard, Andre; Ledu, Christophe; Phelipot, Pascal; Heurtebise, Serge; Boudry, Pierre. |
| The distinction of the two cupped oysters Crassostrea gigas (Thunberg, 1793) and Crassostrea angulata (Lamark, 1819) into two species was chiefly due to their differing geographical distributions, C. gigas being present in Asia and C. angulata in Europe. Today it is commonly accepted that C. angulata and C. gigas are a single species according to morphological, genetic and F1 hybridization data. However, the demonstration of the fertility of their hybrids and the absence of any reproductive isolation remained to be investigated. Consequently, we studied the fertility of hybrids and sperm competition by performing three different experiments and producing G1 and G2 hybrid progenies between wild populations of C. angulata and C. gigas. Progenies showed very... |
| Tipo: Text |
Palavras-chave: Crassostrea angulata; Crassostrea gigas; Developmental yields of larvae; Fertility; Controlled crosses; Hybridization. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-1395.pdf |
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| Le Moullac, Gilles; Rouxel, Catherine; Vonau, Vincent; Ledu, Christophe; Cochard, Jean-claude. |
| Afin de mener à bien le programme Maîtrise de la Reproduction chez l’huître perlière Pinctada margaritifera dont la perspective est l’amélioration génétique, il est essentiel de contrôler les croisements au niveau individuel. Ces croisements ne pourront être contrôlés que dans la mesure où les gamètes mâles et femelles sont obtenus séparément. Ceci permettra aussi de valider les travaux en cryoconservation des spermatozoïdes et de faciliter la production de polyploïdes. Ces travaux répondent aussi aux préoccupations d’amélioration génétique. Cette étude est basée sur deux approches complémentaires. D’une part, l’étude de la maturation ovocytaire in vitro afin de déterminer les conditions qui permettront de disposer d’ovocytes prêts à être fécondés. D’autre... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00182/29290/27731.pdf |
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| Lapegue, Sylvie; Diaz-almela, E.; Launey, Sophie; Ledu, Christophe; Boudry, Pierre; Naciri-graven, Yamama; Bonhomme, Francois. |
| Natural populations of the European flat oyster, Ostrea edulis, have been harvested since Roman times. This species is distributed along the European Atlantic coasts, from Norway to Morocco, as well as the Mediterranean Sea and Black sea coasts. Previous studies, based on allozymes, have concluded that isolation by distance is taking place in the Mediterranean sea and the Atlantic ocean. Because of the presumed non neutrality of these markers, another approach was made to examine the genetic differentiation of this species using nuclear microsatellite and mitochondrial markers, both considered as neutral, and to compare the results to those observed with allozymes. |
| Tipo: Text |
Palavras-chave: Microsatellite markers; Ostrea edulis; Flat oyster; Genetic. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/acte-3497.pdf |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Bodoy, Alain; Heurtebise, Serge; Garnier, Jacqueline; Baud, Jean-pierre; Nourry, Max; Haure, Joel; Martin, Anne-genevieve; Claude, Serge; Barret, Jean; Devauchelle, Nicole; Joly, Jean-pierre; Goulletquer, Philippe; Coatanea, Denis; Oheix, Jocelyne; Zanette, Yvan; Blachier, Philippe. |
| This fourth part of the polyploidisation program reports the experiments that were conducted in 1992 and that were devoted to : - the acquiring of a new method using an epifluroescent microscope - the development o a new technique for inducing polyploidy - the triploidy induction for the Europena clam Ruditapes decussatus - the settlement of performance controls conducted on diploid and triploid populations of Ostrea edulis - results of performance controls conducted on diploid and triploid populations of Crassostrea gigas and Ruditapes philippinarum |
| Tipo: Text |
Palavras-chave: Ruditapes decussatus; Ruditapes philippinarum; Ostrea edulis; Crassostra gigas; Cytongenetics; Polyploidy; Ruditapes decussatus; Ruditapes philippinarum; Ostrea edulis; Crassostrea gigas; Cytogénétique; Polyploïdie. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/1993/rapport-3859.PDF |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Baud, Jean-pierre; Nourry, Max; Haure, Joel; Heurtebise, Serge; Garnier, Jacqueline; Martin, Anne-genevieve; Claude, Serge; Langlade, Aime; Joly, Jean-pierre; Goulletquer, Philippe; Ruelle, Francois; Coatanea, Denis; Oheix, Jocelyne; Vercelli, Catherine; Chabirand, Jean-michel; Maurer, Daniele; Borel, Michel; Cardinal, Mireille; Cornet, Josiane; Le Pennec, Marcel; Le Mercier, A.. |
| This fifth part of the polyploidisation program reports the experiments that were conducted in 1993 and that were devoted to : - monitoring growth performance of Ostrea edulis diploids and triploids in La Trinité sur Mer and Palavas - monitoring growth performance of Crassostrea gigas diploids and triploids in Port en Bessin, Marennes Oleron (2 locations), Arcachon and Palavas - comparative study of gametogenesis for C. gigas diploids and triploids - comparative study of C. gigas diploids and triploids using sensorial analysis At the end of fifth year, it was clear that triploids are advantageous although such a statement must be moderated according to locations. The gametogenesis stydy showed that triploidy is associated with partial to complete... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Ostrea edulis; Cytogenetics; Polyploidy; Crassostra gigas; Ostrea edulis; Cytogénétique; Polyploïdie. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/1994/rapport-3860.PDF |
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| Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe. |
| A novel method using 6-dimcthylaminopurinc (6-0MAP) has recently been demonstrated to be a good triploid inductor for bivalve molluscs. The effects of 6-DMAP concentration, timing of treatment after fertilization and treatment duration on survival and triploid induction of Crassostrea gigas (Thunberg) embryos were examined. An influence of sperm concentration was also detected and discussed. Survival to D-stage was inversely related to 6-DMAP concentration and the percentage of triploids was shown to be 6-DMAP dose dependent. Two optimal moments for treatment application were determined corresponding to extrusions of the first and second polar bodies. Optimal treatment of 450 µmol/l 6-DMAP beginning 15 min after fertilization over a 10 min period yielded... |
| Tipo: Text |
Palavras-chave: Genetic; Triploid induction; Crassostrea gigas; 6 DMAP; Triploid; Oysters. |
| Ano: 1994 |
URL: http://archimer.ifremer.fr/doc/1994/publication-3198.pdf |
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| Chavanne, Herve; Maurouard, Elise; Yonneau, Caroline; Heroin, Debora; Ledu, Christophe; Degremont, Lionel; Benabdelmouna, Abdellah. |
| Afin de permettre l’approvisionnement partiel des établissements ostréicoles en naissain « à survie améliorée », un protocole d’approvisionnement partiel de sauvegarde (PSI) a été mis en place en 2010 entre le CNC, les CRCs, les écloseurs et l’Ifremer afin de fournir aux ostréiculteurs du naissain présentant les meilleures chances de survie face aux mortalités estivales. Il avait ainsi été décidé que des écloseries privées produiraient du naissain triploïde « à survie améliorée » en 2010 à partir de géniteurs, femelles diploïdes et mâles tétraploïdes, sélectionnés et fournis par Ifremer. Sur la base notamment des recommandations des Assises de la Conchyliculture, l’opération a été reconduite en 2011 (PSII) et 2012 (PSIII). Suite aux productions réalisées... |
| Tipo: Text |
Palavras-chave: Mortalités; Crassostrea gigas; Huîtres creuses; Triploïde R; Sélection Génétique. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00143/25412/23563.pdf |
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| Degremont, Lionel; Maurouard, Elise; Connes, Coralie; Ledu, Christophe; Benabdelmouna, Abdellah. |
| Depuis 2008 l’ostréiculture française subit des mortalités massives d'huîtres creuses, Crassostrea gigas, qui menacent les approvisionnements en naissains et, par voie de conséquence, fragilise la filière ostréicole. C’est dans ce contexte qu'a été mis en place à partir de 2010 une opération désignée sous le terme plan de sauvegarde. Cette opération sous forme contractuelle fait intervenir l'Ifremer, des écloseries privées, le Ministère en charge de l'Agriculture et le CNC. Le premier plan de sauvegarde (PS1) a été initié en 2010, suivi par un deuxième en 2011 (PS2), et un troisième en 2012 (PS3). L’objectif premier de ce plan est d’apporter une réponse temporaire au déficit de production grandissant en fournissant aux écloseries des animaux présentant une... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00229/34041/32448.pdf |
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| Boudry, Pierre; Launey, Sophie; Diaz-almela, E.; Naciri-graven, Yamama; Ledu, Christophe; Mira, Sara; Taris, Nicolas; Bonhomme, Francois; Lapegue, Sylvie. |
| Nowadays, PCR-based DNA markers allow the study of diversity and differentiation of marine organisms at different stages of their life cycle. Our study of European flat oyster (Ostrea edulis) populations has aimed to describe their spatial and temporal dynamics. First, we analyzed adults sampled over the natural range of the species. An Atlantic/Mediterranean differentiation pattern was observed. Results were congruent between allozymes, microsatellites and mitochondrial DNA and support an isolation by distance model. High variability was observed in the breadth of diversity between populations using a mitochondrial marker, this highlights the small effective population sizes in some locations. A 10-fold quantitative difference was observed in Fst... |
| Tipo: Text |
Palavras-chave: Larvae; Reproduction; Genetic; Ostrea edulis; European flat oyster; Population genetics. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/acte-3493.pdf |
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| Registros recuperados: 48 | |
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