Consulta: creatorFacets:"Ledu, Christophe"
Registros recuperados: 48
Data/hora: 11/06/2024 07:17:21

Analysis of shell colour determinism in the Manila clam Ruditapes philippinarum
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Peignon, Jean-marie; Gerard, Andre; Naciri, Yamama; Ledu, Christophe; Phelipot, Pascal.
The Manila clam presents a large polymorphism for shell colours and patterns. No experiment has been conducted to study the determinism of such a polymorphism which has been well known for a long time. The aim of this study was firstly to determine the genetic variation for shell colour and secondly to produce some homozygous lines for the shell colouring. These lines could then be used as controls for laboratory experiments. The colouring is defined by three characters: asymmetry, ornamentation and hue. Clams with asymmetrical colouring are not fully pigmented, except for a posterior band on the left valve. Clams with symmetrical colouring are fully pigmented on the two valves. Four cross series were conducted between the different characters: Asymmetry...
Tipo: Text
Palavras-chave: Mollusque; Bivalve; Palourde; Ruditapes philippinarum; Génétique; Hérédité mendélienne; Coloration; Asymétrie; Mollusc; Bivalve; Manila clam; Ruditapes philippinarum; Genetics; Mendelian inheritance; Colouration; Asymmetry.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/1995/publication-3204.pdf

Obtention de souches conchylicoles performantes par polyploïdisation (3ème partie)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gerard, Andre; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Noiret, Christophe; Bodoy, Alain; Heurtebise, Serge; Garnier, Jacqueline.
The third part of the polyploidisation program of the main French species of commercial interest, this report presents the actions and results for the year 1991 which was devoted to:- continuation of the development trials of the triploidy induction technique in Ruditapes decussates (i.e. indigenous clam)- production of diploid and triploid populations of Ostrea edulis (i.e. flat oyster)- control of diploid and triploid population performances in cupped oyster and Pacific clam in their natural habitat- continuation of the development of a ploidy control technique through image analysis- beginning of the development of a new polyploidy induction technique in bivalve molluscs
Tipo: Text
Palavras-chave: Ruditapes decussatus; Ostrea edulis; Ruditapes philippinarum; Crassostrea gigas; Imagerie numérique; Cytogénétique; Polyploïdie.
Ano: 1992
URL: http://archimer.ifremer.fr/doc/1992/rapport-3857.PDF

Production en masse de Skeletonema costatum en bassins extérieurs par fertilisation minérale : étude d'un cycle estival
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gautier, Dominique; Ledu, Christophe; Hussenot, Jerome; Gerard, Andre.
La production en masse de Skeletonemca costatum par fertilisation minérale ((N, P, Si) a été étudiée à l'écloserie IFREMER de Ronce-les-Bains sur un bassin de 200 m3 à fond bâché endant un cycle de 11 jours en juillet 1992. (...)
Tipo: Text
Palavras-chave: Phyoplancton; Nutriments; Production en masse; Skeletonema costatum; Diatomées.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00020/13113/10121.pdf

Optimization of triploid induction by the use of 6-DMAP for the oyster Crassostrea gigas (Thunberg)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Is fertility of hybrids enough to conclude that the two oysters Crassostrea gigas and Crassostrea angulata are the same species?
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Obtention de souches conchylicoles performantes par polyploïdisation (5ème partie)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Autotetraploid Pacific oysters (Crassostrea gigas) obtained using normal diploid eggs: induction and impact on cytogenetic stability
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Benabdelmouna, Abdellah; Ledu, Christophe.
We describe two methods of producing viable and fertile autotetraploid Pacific oyster (Crassostrea gigas Thunberg) based on the use of normal-sized oocytes produced by normal diploid females. Our methods showed that the oocyte size is not a limiting factor for the success of the induction to autotetraploidy. These methods offer means of direct introgression of genetic progress from elite diploid lines to tetraploids used as broodstock, avoiding a triploid step with the risk of transferring undesirable traits from highly fecund triploids. High variability in the level of cytogenetic stability was found among the different tetraploid oysters tested showing that induction method has an important impact on the long-term cytogenetic stability of the...
Tipo: Text
Palavras-chave: Oyster; Tetraploid induction; Mosaicism; Aneuploidy; Cytogenetic stability.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00278/38924/37464.pdf

The mass mortality of blue mussels (Mytilus spp) from the Atlantic coast of France is associated with heavy genomic abnormalities as evidenced by flow cytometry
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Benabdelmouna, Abdellah; Ledu, Christophe.
Since 2014, France’s blue mussel industry has been facing heavy mortality outbreaks (90-100%) affecting both juveniles and adults. This report presents evidence of heavy genomic abnormalities associated with mortality outbreaks in blue mussels, Mytilus edulis-galloprovincialis, from the Atlantic coast of France. In this study, ploidy characteristics of hemic cells were investigated using Flow CytoMetry (FCM), revealing an unusual, broad continuum of ploidy distribution from hypodiploidy to tetraploidy. FCM was additionally used to evaluate, at individual and populations levels, different thresholds of genomic abnormality (GA%) using the percentage of non-diploid nuclei. Individual mussels were considered to be abnormal when more than 10% of hemocytes in...
Tipo: Text
Palavras-chave: Mussels; Mortality; Cytogenetic quality; Hemocytes; Ploidy.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00341/45171/44566.pdf

Acclimatation de nouvelles espèces d'huîtres creuses du genre Crassostrea: hybridation et conservatoire de souches. Contrat Région Poitou-Charentes 1994-1998 - 1ère partie : rapport année 1994
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Naciri, Yamama; Launey, Sophie; Ledu, Christophe; Phelipot, Pascal; Heurtebise, Serge; Gerard, Andre.
Le laboratoire IFREMER "Génétique Aquaculture et Pathologie" (GAP) (La Tremblade et Bouin) a entrepris des actions de recherche sur ces différents points. L'Unité de Recherche en Génétique, en collaboration avec tous Ies membres du Réseau Génétique Mollusques (REGEMO) a axé une partie de ses travaux sur l'acclimatation et l'hybridation de différentes espèces du genre Crassostrea. Ces recherches ont débuté avec le soutien du Conseil Général de Charente-Maritime depuis 1992 sur des essais d'acclimatation de C. virginica, l'huître creuse américaine. En prolongement de cette étude, l'URGE a proposé à la région Poitou Charentes un programme de recherche plus vaste sur l'ensemble des espèces d'huîtres creuses. Le contrat de plan Etat-Région a été signé en...
Tipo: Text
Palavras-chave: Génétique; Acclimatation; Hybridation; Crassostrea; Saccostrea; Génétique population.
Ano: 1994
URL: http://archimer.ifremer.fr/doc/00044/15517/12904.pdf

Acclimatation de nouvelles espèces d'huîtres creuse du genre Crassostrea: hybridation et conservatoire de souches - Contrat de Plan Etat Région Poitou-Charentes 1994-1998 - Synthèse finale
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Heurtebise, Serge; Huvet, Arnaud; Chollet, Bruno; Ledu, Christophe; Phelipot, Pascal; Gerard, Andre.
Actions menées de 1994 à 1998 au sein du conservatoire de souches : 1. Résultats des importations, acclimatation et hybridation. a) Rappel des conditions d'introduction de nouvelles souches. L'importation de toute espèce est conditionnée par les résultats d'une enquête préliminaire dont l'objet est de rechercher les exigences écologiques de l'espèce et la situation épidémiologique dans son milieu d'origine. Le travail du LGP et de ses partenaires a été partagé en différentes actions: 1. Recherche de contacts dans divers pays étrangers, en vue de l'importation d'huîtres présentant des caractéristiques intéressantes. 2. Importation : L'importation se fait selon les normes du CIEM (Conseil International pour l'Exploration de la Mer) : contrôles pathologiques...
Tipo: Text
Palavras-chave: Génétique; Acclimatation; Hybridation; Marqueurs moléculaire; Marqueurs populations; Crassostrea.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00044/15520/12907.pdf

Acclimatation de nouvelles espèces d'huîtres creuses du genre Crassostrea: hybridation et conservatoire de souches. Amélioration de la qualité chez l'huître creuse Crassostrea gigas par sélection de souches performantes - Rapport année 1996
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Naciri, Yamama; Collet, Bertrand; Cornette, Florence; Heurtebise, Serge; Ledu, Christophe; Chollet, Bruno; Phelipot, Pascal; Gerard, Andre.
Les objectifs pour l'année 1996 étaient les suivants: Poursuivre les premières reproductions des espèces pour lesquelles nous disposons de géniteurs GO. L'objectif est toujours de limiter le stockage d'animaux importés en produisant une descendance simultanément à des témoins C. gigas qui serviront de comparaison. Tenter des hybridations inter-spécifiques des différents taxons présents au sein du conservatoire en fonction des connaissances disponibles dans la littérature sur ce sujet (voir pour revue Gaffney et Allen, 1993). • Importer de nouvelles souches ou espèces. Élargir la gamme des espèces présentes au sein du conservatoire de souches (les capacités d'accueil de la salle de quarantaine étant Limitée).
Tipo: Text
Palavras-chave: Génétique; Acclimatation; Hybridation; Crassostrea; Sélection génétique; Saccostrea commercialis.
Ano: 1996
URL: http://archimer.ifremer.fr/doc/00044/15516/12903.pdf

Plan de sauvegarde 2011 : synthèse de résultats 2011-2012
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Etudes des bases génétiques et de la varibailité des caractères physiologiques impliqués dans la croissance chez l'huître creuse Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Acclimatation de nouvelles espèces d'huîtres creuses du genre Crassostrea : hybridation et conservatoire de souches. Contrat Région Poitou-Charentes 1999 - Convention 99 RPC-A-203 "Génétique"
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Heurtebise, Serge; Lapegue, Sylvie; Ledu, Christophe; Phelipot, Pascal; Gerard, Andre.
Dans le cadre du plan Etat-Région 1994-1998, un programme de conservatoire de souches a été initié au Laboratoire IFREMER de La Tremblade. Ce conservatoire a pour objectif d'acclimater différentes espèces ou souches d'huîtres creuses (genres Crassostrea et Saccostrea) afin d'acquérir des connaissances sur ces espèces et d'évaluer l'intérêt qu'elles pourraient présenter pour l'ostréiculture locale. L'importation d'espèces étrangères sur les côtes françaises est désormais strictement réglementée: la dissémination d'une nouvelle espèce peut se révéler néfaste d'un point de vue écologique et nuire aux productions existantes. De plus, ces huîtres peuvent être porteuses de pathogènes qui, s'il venaient à se répandre dans le milieu, pourraient toucher les stocks...
Tipo: Text
Palavras-chave: Génétique; Acclimatation; Croisement; Crassostrea gigas; Crassostrea ariakensis; Crassostrea sikamea; Hybridation.
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00044/15514/12901.pdf

Historique, expériences en cours et perspectives du programme de sélection de l'huître plate Ostrea edulis pour la résistance à la bonamiose
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Population genetics of the European flat oyster (Ostrea edulis) : from larvae to populations
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Essai d'acclimatation de Crassostrea virginica et performances biologiques comparées avec Crassostrea gigas (2ème partie)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Effect of ploidy on the mortality of Crassostrea gigas spat caused by OsHV-1 in France using unselected and selected OsHV-1 resistant oysters
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Study of the reproductive potential of triploid oysters
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Normand, Julien; Boudry, Pierre; Cornette, Florence; Ledu, Christophe.
Reproduction was studied in triploid Crassostrea gigas, by crossing gametes from diploid and triploid parents.Triploids are able to produce viable gametes and their resulting progeny consisted in diploids, aneuploids and polyploids. Gametes from triploid parents frequently led to abnormal polar body formation, even before caryogamy occurred. A high frequency of aneuploids was observed, related to the missegregation of chromosomes during meiosis in triploids. This might be due to the observed incomplete synapsis in triploid eggs during Prophase I. The proportion of aneuploids decreased during larval development, reflecting differential mortality between ploidy levels. Due to limited gonadic development and high larval mortality rates, the reproductive...
Tipo: Text
Palavras-chave: Triploid; Genetic; Oysters; Crassostrea gigas.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3319.pdf

A complementary method for production of tetraploid Crassostrea gigas using crosses between diploids and tetraploids with cytochalasin B treatments
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mccombie, Helen; Ledu, Christophe; Phelipot, Pascal; Lapegue, Sylvie; Boudry, Pierre; Gerard, Andre.
We present a new method to produce tetraploid Crassostrea gigas by cytochalasin B inhibition of polar body 2 expulsion in diploid females crossed with tetraploid males. This offers a means of direct introgression of genetic characters from selected diploid to tetraploid lines, avoiding a triploid step. Offspring larval ploidy shifted over time and depended on size, with tetraploids more frequent among the smaller larvae and triploids among the large. Viable tetraploids were found at 4 and 6 months, indicating the technique was successful. The possibility that gynogenesis occurred was tested by microsatellite analysis to confirm the presence of paternally inherited alleles. These were present in all animals of the 2n x 4n + CB (female first) cross. However,...
Tipo: Text
Palavras-chave: Oyster breeding; Gynogenesis; Polar body; Cytochalasin B; Polyploidy; Crassostrea gigas.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-632.pdf

Synthesis of the “PLAN DE SAUVEGARDE” using selected all-triploid oysters to reduce the shortage of spat in France due to OsHV-1–associated mortality in Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Dégremont, Lionel; Maurouard, Elise; Ledu, Christophe; Benabdelmouna, Abdellah.
Due to massive mortality of Crassostrea gigas spat in France since 2008, a “plan de sauvegarde” was set up from 2011 to 2014 (hereafter referred to as PS1 to PS4), in order to reduce the shortage of spat. This plan involved the participation of commercial hatcheries, the French Research Institute for Exploitation of the Sea (Ifremer), and the Direction des Pêches Maritimes et de l'Aquaculture (DPMA) of the French Ministry of Agriculture. It was based on selecting diploid lines of C. gigas for their higher resistance to the oyster herpesvirus OsHV-1 (2nR group), and one of these lines was subsequently tetraploidized (4nR group). Both the 2nR and 4nR groups were produced by Ifremer, and then transferred to commercial hatcheries that produced the selected...
Tipo: Text
Palavras-chave: Triploids; Mortality; Crassostrea gigas; OsHV-1; Disease resistance.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00484/59596/62598.pdf

Chromosome loss in bi-parental progenies of tetraploid Pacific oyster Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mccombie, Helen; Lapegue, Sylvie; Cornette, Florence; Ledu, Christophe; Boudry, Pierre.
Alterations of chromosome number have been observed in the somatic tissue of Crassostrea gigas diploids and artificial polyploids. Tetraploid oysters with abnormal chromosome numbers in some or all of their tissue are considered undesirable as parents either for triploids (produced via a cross with diploids and of aquacultural interest) or for tetraploid breeding. Aneuploid tetraploid oysters may confer the tendency to lose chromosomes and to revert to lower ploidy levels to their offspring. More directly, their offspring could have a lower ploidy because of potential links between somatic and gametic chromosome loss. The present study evaluated the phenomenon in six bi-parental tetraploid families bred from parents of differing somatic ploidy quality. The...
Tipo: Text
Palavras-chave: Crassostrea gigas; Mitosis; Chromosome; Cytogenetics; Aneuploid; Polyptoid; Tetraploid; Oyster.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-633.pdf

Fluorescence in situ hybridization (FISH) or rDNA genes (5S and 18-5.8-28S) as a tool for chromosomal tagging and to assess the occurrence of somatic and sperm aneuploidy in Pacific oyster Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Effects of cytochalasin B on fertilization and ploidy in the Pacific oyster Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ledu, Christophe; Mccombie, Helen.
The effects of cytochalasin B on fertilization and ploidy in Crassostrea gigas were examined in a controlled experiment. This enabled us to better understand why variable ploidy results have been found with the retention of polar bodies in previous studies on bivalve mollusks, and what the interaction with fertilization may be. By looking at the early development of Crassostrea gigas embryos with sequential samples stained using Hoechst 33258, a fluorescent DNA-specific dye, we compared normal evolution of fertilized eggs with that obtained with cytochalasin B treatment. In treated eggs, embryos with both three and four pronuclei were found after the second meiotic division. When embryos had three pronuclei, these were identified as the female pronucleus...
Tipo: Text
Palavras-chave: Crassostrea gigas; Fertilization; Cytochalasin B; Polar body; Polyploidy.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/publication-2845.pdf

Gamete quality in triploid Pacific oyster (Crassostrea gigas)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Induced triploidy in the European clam, Ruditapes decussatus (L.) and performance of triploid larvae
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Amélioration de la qualité chez l'huître creuse Crassostrea gigas par sélection de souches performantes - Contrat de Plan Etat Région Poitou-Charentes 1994-1998 - Rapport année 1995
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Naciri, Yamama; Heral, Maurice; Collet, Bertrand; Bougrier, Serge; Geffard, Olivier; Ledu, Christophe; Phelipot, Pascal; Heurtebise, Serge; Gerard, Andre.
Le programme de recherche présenté ci-dessous est le fruit d'une réflexion conjointe entre généticiens et physiologistes afin de mettre sur pied un ensemble d'expériences permettant d'étudier les bases génétiques de la variabilité des caractères impliqués dans la croissance chez l'huître creuse, Crassostrea gigas.
Tipo: Text
Palavras-chave: Génétique; Sélection génétique; Génétique des populations; Croissance; Crassostrea gigas.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/00044/15518/12905.pdf

Obtention de souches conchylicoles performantes par polyploïdisation (4ème partie)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Image analysis : a new method for estimating triploidy in commercial bivalves
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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 &amp; 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

Acclimatation de nouvelles espèces d'huîtres creuses du genre Crassostrea: hybridation et conservatoire de souches. Amélioration de la qualité chez l'huîtres creuses Crassostrea gigas par sélection de souches performantes - Contrat de Plan Etat Région Poitou-Charentes 1994-1998 - Convention 97 RPC-R-54 "Génétique" - Rapport année 1997
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Lapegue, Sylvie; Goyard, Emmanuel; Heurtebise, Serge; Ledu, Christophe; Phelipot, Pascal; Gerard, Andre.
Les objectifs pour l'année 1997 étaient les suivants : • Poursuivre les premières reproductions des espèces pour lesquelles nous disposons de géniteurs GO. L'objectif est toujours de limiter le stockage d'animaux importés en produisant une descendance simultanément à des témoins C. gigas qui serviront de comparaison. • Tenter des hybridations inter-spécifiques des différents taxons présents au sein du conservatoire en fonction des connaissances disponibles dans la littérature sur ce sujet (voir pour revue Gaffney et Allen, 1993). • Importer de nouvelles souches ou espèces. Élargir la gamme des espèces présentes au sein du conservatoire de souches (les capacités d'accueil de la salle de quarantaine étant limitée).
Tipo: Text
Palavras-chave: Génétique; Génétique des Populations; Acclimatation; Hybridation; Marqueurs génétiques; Sélection génétique; Crassostrea gigas.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/00044/15519/12906.pdf

Essai d'acclimatation de Crassostrea virginica et performances biologiques comparées avec Crassostrea gigas (1ère partie)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Baud, Jean-pierre; Nourry, Max; Renault, Tristan; Cochennec, Nathalie.
Premier volet du programme d'essai d'acclimatation de l'huître américaine Crassostrea virginica, ce rapport présente les actions et les résultats de l'année 1992 qui a été consacrée à : • l'importation selon les normes du CIEM d'un lot de 50 huîtres en provenance d'Angleterre, • leur élevage en salle de quarantaine et leur conditionnement en vue d'une accélération de la maturation sexuelle, • l'obtention d'une première génération, ainsi que son suivi en élevage larvaire et en micronurserie à l'URGE-La Tremblade, • au contrôle des performances comparées des deux populations de C. virginica et de C. gigas en nurserie de prégrossissement à l'URRA-Bouin pendant toute la période automnale et hivernale. Au terme de cette première année d'étude il apparait que la...
Tipo: Text
Palavras-chave: Mollusques; Acclimatation; Crassostrea virginica; Crassostrea gigas; Génétique; Pathologie.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00077/18843/16417.pdf

Mortality investigation of Mytilus edulis and Mytilus galloprovincialis in France: An experimental survey under laboratory conditions
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Benabdelmouna, Abdellah; Garcia, Celine; Ledu, Christophe; Lamy, Pierre; Maurouard, Elise; Degremont, Lionel.
In the context of mass mortality outbreaks affecting adult and juvenile mussels since 2014 in France, two investigations were conducted to study mussel mortality under laboratory conditions in 2015. The first investigated the horizontal transmission of a putative causal agent of the mortality among two stocks of wild Mytilus edulis and the potential genetic resistance of adults and their progenies. The second evaluated the resistance of pure and hybrid crosses of M. edulis and M. galloprovincialis at the spat stage to a mortality outbreak. For the first time in France, we described several mortality outbreaks affecting spat and adult mussels under laboratory conditions. Mortality was observed for seawater temperatures ranging from 10 to 23 °C, although the...
Tipo: Text
Palavras-chave: Mytilus edulis; Mytilus galloprovincialis; Interspecific hybrids; Mortality outbreaks.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55696/57364.pdf

Différenciation génétique des populations d'huître plate européenne, Ostrea edulis, à l'aide de marqueurs des génomes mitochondrial et nucléaire
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Lapegue, Sylvie; Diaz-almela, E.; Launey, Sophie; Ledu, Christophe; Boudry, Pierre; Naciri-graven, Yamama; Bonhomme, Francois.
Two oyster species are cultivated on the French coasts: the Pacific cupped oyster (Crassostrea gigas), which has been introduced from Japan in the 1970's after the disappearance of the Portuguese oyster Crassostrea angulala, and the European flat oyster (Ostrea edulis). During the second half of the 1960's, the latter suffered successively from two diseases caused by protozoan parasites: marteiliosis (also called "maladie des Abers") and bonamiosis. In France, its production dropped from 20,000 tian in the 1960's to 2,000 today. The impact of these two pathogens as well as the exploitation of the remaining stocks show the importance of the conservation of this species, the only natural European species, whose population is more and more fragmented.
Tipo: Text
Palavras-chave: Marqueurs; Génétique population; Génétique; Ostrea edulis; Crassostrea gigas.
Ano: 2001
URL: http://archimer.ifremer.fr/doc/2001/acte-3273.pdf

Mitochondrial and microsatellite genetic differentiation of the flat oyster Ostrea edulis along the european coasts, and comparison with allozyme data
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Etude de la CINétique et DIffusion de la MORtalité (CINDIMOR) chez les juvéniles de l'huître creuse Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Ressources génétiques chez l'huître creuse Crassostrea gigas : variabilité, différenciation et adaptation aux conditions de production en Charente Maritime
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Huvet, Arnaud; Boudry, Pierre; Baud, Jean-pierre; Nourry, Max; Phelipot, Pascal; Gerard, Andre; Ledu, Christophe; Heurtebise, Serge; Cornette, Florence; Blouin, Frederic; Bedier, Edouard; Lapegue, Sylvie.
es marqueurs génétiques, particulièrement bien adaptés à ces problématiques car hypervariables, ont été mis au point récemment dans notre laboratoire en collaboration avec le laboratoire Génome et Populations de Montpellier (CNRS). Ils permettent désormais l'analyse approfondie et la discrimination fine de populations d'huîtres creuses Crassostrea gigas et de rechercher si certaines d'entre-elles n'auraient pas des caractéristiques intéressantes pour l'ostréiculture locale (croissance, résistance estivale, affinage ... ). La diffusion de telles populations auprès de la profession serait plus rapide car il s'agit de la même espèce. Selon les recommandations du CIEM, il faut effectuer une mise en quarantaine des huîtres importées (après contrôles sanitaires)...
Tipo: Text
Palavras-chave: Génétique; Génétique des populations; Marqueurs génétiques; Microsatellite; Huître creuse; Crassostrea gigas.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00044/15563/12952.pdf

CAPRETAR : Etude comparative des caractéristiques cytogénétiques et des performances de survie de naissains sauvages issus du CAPtage PREcoce ou TARdif
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Benabdelmouna, Abdellah; Hemissi, Issam; Bodin, Stephane; Robert, Stephane; Ledu, Christophe; Laporte, Philippe.
L'action de recherche CAPRETAR (CAptage PREcoce ou TARdif: 2009-2010) a été réalisée dans le cadre du Contrat de Plan Etat Région - Poitou Charentes (CPER-PC 2007- 2013) développement durable des Pertuis Charentais. Cette action, s 'inscrit dans le cadre d 'un lien direct qui existerait entre la nature précoce/tardive d 'un captage naturel et la qualité des naissains de l'huître creuse C. gigas qui en sont issus (qualité génétique : « R » résistante ou « S » sensible et qualité génomique : taux des aneuploïdies et des dommages à l'ADN). L'objectif de cette action vise à estimer durant l 'année (2010) les performances relatives de survie de naissains issus d 'un captage précoce ou tardif réalisé l'année précédente (2009). Les résultats escomptés visent à...
Tipo: Text
Palavras-chave: Génétique; Cytogénétique; Captage; Reproduction; Huîtres creuses; Crassostrea gigas.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00062/17283/14794.pdf

Plan de sauvegarde 2012, 3ème édition : synthèse des résultats 2012-2013
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34041/32448.pdf

Acclimatation de nouvelles espèces d'huîtres creuses du genre Crassostrea: hybridations et conservatoire de souches. Contrat de Plan Etat Région Poitou- Charentes 1994-1998 - Convention 95/RPC-R-57 "Génétique" - Rapport année 1995
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Naciri, Yamama; Heurtebise, Serge; Delsert, Claude; Ledu, Christophe; Phelipot, Pascal; Chollet, Bruno; Cochennec, Nathalie; Gerard, Andre.
Le laboratoire IFREMER "Génétique Aquaculture et Pathologie" (GAP) (La Tremblade et Bouin) a entrepris des actions de recherche sur ces différents points. L'Unité de Recherche en Génétique, en collaboration avec tous les membres du Réseau Génétique Mollusques (REGEMO), a axé une partie de ses travaux sur l'acclimatation et l'hybridation de différentes espèces du genre Crassostrea. Ces recherches ont débuté avec le soutien du Conseil Général de Charente-Maritime depuis 1992 sur des essais d'acclimatation de C. virginica, l'huître creuse américaine. En prolongement de cette étude, l'URGE a proposé à la région Poitou-Charentes un programme de recherche plus vaste sur l'ensemble des espèces d'huîtres creuses.
Tipo: Text
Palavras-chave: Génétique; Acclimatation; Hybridation; Crassostrea virgnica.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/00044/15515/12902.pdf

Le contrôle des croisements chez l’huître perlière Pinctada margaritifera : La maturation ovocytaire in vitro et l’induction de la ponte
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00182/29290/27731.pdf

REGEMO Réseau Génétique Mollusques. Compte rendu de la réunion des 13 et 14 décembre 1993 - Nantes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gerard, Andre; Naciri, Yamama; Peignon, Jean-marie; Ledu, Christophe; Phelipot, Pascal; Baud, Jean-pierre; Nourry, Max; Haure, Joel; Coatanea, Denis; Oheix, Jocelyne; Vercelli, Catherine; Chabirand, Jean-michel; Borel, Michel; Maurer, Daniele; Heurtebise, Serge; Garnier, Jacqueline; Martin, Anne-genevieve; Tige, Gilbert; Mazurie, Joseph; Langlade, Aime.
Cette réunion des membres du Réseau Génétique Mollusques avait pour objet de faire un bilan provisoire des actions en cours et surtout de mettre en place les protocoles et les calendriers du début de l'année 1994. La première demi-journée a été réservée à un exposé de Yamama NACIRI sur les bases de la Génétique Quantitative et ses applications dans le cadre des programmes de sélection des mollusques.La deuxième demi-journée a été consacrée au bilan des actions de 1993. Les représentants de chaque site, intervenant dans une opération du réseau en 1993, ont fait une présentation orale de leurs résultats. Un résumé de chaque intervention vous est fourni dans ce document. Il est important de souligner que tous ces bilans sont provisoires, en premier lieu parce...
Tipo: Text
Palavras-chave: Génétique; Sélection génétique; Huître plate; Ostrea edulis; Croissance; Génétique population.
Ano: 1993
URL: http://archimer.ifremer.fr/doc/00049/15982/13425.pdf

Diversité et différentiation génétique chez l'huître plate européenne : de la population à l'individu (Actes)
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Launey, Sophie; Diaz-almela, A.; Naciri-graven, Yamama; Ledu, Christophe; Mira, S.; Taris, Nicolas; Bonhomme, Francois; Lapegue, Sylvie.
PCR-based DNA markers enable the study of diversity and differentiation of marine organisms at different stages of their life cycle. Our study of European fiat oyster (Ostrea edulis) populations 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. Similar patterns of variation were found using allozymes, microsatellites and mitochondrial DNA, aIl which support an isolation by distance model. High variability was observed in the range of diversity between populations using a mitochondrial marker, a reflection of small effective population sizes in sorne locations. A 10fold quantitative difference was observed in Fst,...
Tipo: Text
Palavras-chave: Recruitment; Diversity; Molecular markers; Population genetics; Ostrea edulis; Flat oyster; Dynamique de recrutement; Diversité génétique; Microsatellites; Marqueurs moléculaires; Génétique des populations; Ostrea edulis; Huître plate.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/acte-2851.pdf

Genomic abnormalities affecting mussels (Mytilus edulis-galloprovincialis) in France are related to ongoing neoplastic processes, evidenced by dual flow cytometry and cell monolayer analyses
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Chromosome loss in tetraploid families of the Pacific oyster Crassostrea gigas
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mccombie, Helen; Lapegue, Sylvie; Cornette, Florence; Ledu, Christophe; Boudry, Pierre.
Alterations of  chromosome number have been observed in the somatic tissue of  Crassostrea gigas diploids and artificial polyploids bred in this species.   Tetraploid animals with lower chromosome counts in some or all of their somatic tissue are considered undesirable as parents either for commercial triploids (produced via a  cross with diploids) or for tetraploid breeding because (1) they may confer the tendency to lose chromosomes and revert to lower ploidy levels to their offspring or (2) their offspring could have a lower ploidy directly because of potential links between somatic and gametic chromosome loss.  The present study evaluated the phenomenon in bi-parental tetraploid families bred from parents of differing ploidy quality, including a...
Tipo: Text
Palavras-chave: Tetraploid; Chromosome; Genetic; Crassostrea gigas; Oyster.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/acte-3435.pdf

Ressources génétiques chez les huîtres creuses : conservatoire de souche et marqueurs moléculaires
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Heurtebise, Serge; Collet, Bertrand; Cornette, Florence; Ledu, Christophe; Phelipot, Pascal; Gerard, Andre.
The cupped oyster strain bank was created at Ifremer at La Tremblade in 1992. It was funded by the Poitou-Charentes regional council. Its goals were: 1. to study the intra- and interspecific genetic differentiation within the genus Crassostrea. 2. to study acclimatization potential of foreign oysters in French waters in order to identify species that could replace Crassostrea gigas in case of a major disease outbreak in C. gigas or in case of a need or desire to diversify shellfish production. 3. to study the possibility of interspecific hybridisation in the genus Crassostrea and hybrid performance.
Tipo: Text
Palavras-chave: Saccostrea commercialis; Crassostrea rhisophorae; Crassostrea gasar; Crassostrea sikamea; Crassostrea virginica; Crassostrea rivularis; Crassotea angulata; Crassostrea gigas; Génétique.
Ano: 1997
URL: http://archimer.ifremer.fr/doc/1997/acte-3242.pdf

Contrôle de la gamétogénèse des huîtres creuses et plates. Relations "reproduction" et "génétique"
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gerard, Andre; Naciri-graven, Yamama; Boudry, Pierre; Launey, Sophie; Heurtebise, Serge; Ledu, Christophe; Phelipot, Pascal.
At the end of the 1980s, after two decades of aquaculture research in molluscs, Ifremer initiated its first genetic studies. These new studies quickly revealed the limits of knowledge in aquaculture, particularly in terms of controlling oyster reproduction. This presentation attempts to summarize the available information on genetics in aquaculture. In particular, breeding practices in the 1980s involved populations of broodstock, while genetics requires modern techniques where individuals, not just populations, can be identified. Controlling reproduction at the individual level in oysters raises new questions that existing protocols cannot address, especially in terms of controlling sex determination, individual maturity, spawning synchrony, chemical...
Tipo: Text
Palavras-chave: Gamètes; Fécondation; Induction ponte; Reproducteur; Conditionnement; Gamétogénèse; Génétique; Reproduction; Crassostrea gigas; Huîtres.
Ano: 1995
URL: http://archimer.ifremer.fr/doc/1995/acte-3210.pdf

Programme 3 : Gestion durable des productions ostréicoles : les apports de la génétique. Convention 2000 RPC-A-530 Ifremer - Région Poitou-Charentes
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Boudry, Pierre; Huvet, Arnaud; Fabioux, Caroline; Lapegue, Sylvie; Heurtebise, Serge; Ledu, Christophe; Blouin, Frederic; Phelipot, Pascal; Gerard, Andre.
L'étude de la variabilité génétique de l' huître creuse Crassastrea gigas est un point essentiel dans la mise en place de programmes de gestion des ressources génétiques et de sélection chez cette espèce. C. gigas, originaire du Japon, a été introduite dans de nombreuses régions du monde et représente aujourd'hui plus de 95 % de la production mondiale d' huîtres. Introduite en France au début des années 1970 pour remplacer l' huître portugaise Crassostrea angulata, c'est aujourd 'hui une ressource de première importance pour notre région. Malgré la maîtrise du cycle de reproduction de l'espèce et son importance commerciale, elle n' a pas été génétiquement améliorée et on peut donc considérer les stocks comme « sauvages» ou « non domestiqués ». De plus, la...
Tipo: Text
Palavras-chave: Génétique; Ressources génétiques; Différenciation génétique; Hybridation; Anomalies chromosomiques; Huîtres creuses; Crassostrea gigas; Crassostrea angulata.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00044/15564/12955.pdf

Blue mussel mortality outbreak in France is associated with heavy genomic abnormalities detected by flow cytometric analysis of hemolymph
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Benabdelmouna, Abdellah; Ledu, Christophe.
Since 2014, blue mussel industry in France has been facing heavy mortality outbreaks (90–100%) affecting both juveniles and adults. This report presents evidence of heavy genomic abnormalities associated with mortality outbreaks in blue mussels from the Atlantic coast of France. Ploidy characteristics of hemic cells were investigated using Flow CytoMetry (FCM), revealing an unusual, broad continuum of ploidy distribution from hypodiploidy to tetraploidy. FCM was additionally used to evaluate, at individual and populations levels, different thresholds of genomic abnormality (GA%)using the percentage of non-diploid nuclei. Individual mussels were considered to be abnormal when more than 10% of hemocytes in S–G2/M phase were present. At the population level,...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00356/46720/46591.pdf