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Registros recuperados: 65 | |
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Gardon, Tony; Huvet, Arnaud; Paul-pont, Ika; Cassone, Anne-laure; Koua, Manaarii Sham; Soyez, Claude; Jezequel, Ronan; Receveur, Justine; Le Moullac, Gilles. |
Pearl-farming leads to significant plastic pollution in French Polynesia (FP) as the end of life of most farming gear is currently poorly managed. Plastic debris released into the aquatic environment accumulates, with potentially detrimental effects on the lagoon ecosystem and pearl oyster Pinctada margaritifera, a species of ecological, commercial and social value. Here, we tested the effects of leachates from new (N) and aged (A) plastic pearl-farming gear (spat collector and synthetic rope) obtained after 24 h and 120 h incubation, on the embryo-larval development of the pearl oyster using an in-vitro assay. Embryos were exposed for 24 h and 48 h to a negative control (0) and the leachate from 0.1, 1, 10 and 100 g of plastic. L−1. After 24 h exposure to... |
Tipo: Text |
Palavras-chave: Aquaculture; Synthetic materials; Hazardous chemicals; Toxicity; Marine bivalve; Early development. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00627/73917/73257.pdf |
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Hui, Belinda; Demoy-schneider, Marina; Vonau, Vincent; Le Moullac, Gilles; Moriceau, Jacques; Le Pennec, Marcel; Cochard, Jean-claude. |
Cryopreservation is a useful tool for genetic improvement which has been applied to several bivalve mollusk species. It would allow to keep the gametes of selected individuals and to preserve ex-situ the biodiversity of wild populations of the black-lip pearl oyster Pinctada margaritifera threatened of standardization by the seed transfers between the islands in French Polynesia. The ability to cryopreserve spermatozoa would bring about significant benefits to the cultured black pearl industry. Sperm freezing supposes the control of different steps: preparation of breeders, sperm collection, evaluation of sperm quality and the freezing process itself. Broodstock conditioning in hatchery allows to obtain gametes from the pearl oyster. Sperm quality is... |
Tipo: Text |
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Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00029/14043/11238.pdf |
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Le Moullac, Gilles. |
Summer mortality of the oyster result from the interaction of many factors. A respiratory assumption proposes a link between the supposed causes of the energy state, the cultivation methods and the medium. This work is focused towards the search for specific metabolic markers of environmental stresses. The cDNA of genes coding for PK and PEPCK were cloned and sequenced in order to detect their regulation level. The sediment nearness affects the state of energy reserves, the metabolic pathways of energy production implying a regulation of the PK. Face to the dissolved oxygen decline, oysters were oxyregulator but with a low regulation ability. In hypoxia, glycolysis was slowed down. PK activity was inhibited resulting from an increase in alanine sensitivity... |
Tipo: Text |
Palavras-chave: Régulation; Enzyme; Expression génique; Anoxie; Bivalve. |
Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/these-4315.pdf |
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Lambert, C.; Moal, J.; Pouvreau, Stephane; Le Moullac, Gilles; Samain, Jean-francois. |
Les mortalités apparaissent toujours très rapidement après le passage de la température de l'eau à 19°C. II a bien été montré que ce n'était pas la valeur absolue de la température qui était associée à la mortalité, puisque des années très chaudes comme 2003, peu de mortalités étaient enregistrées. II s'agit plutôt d'un seuil à partir duquel le risque devient réel. La température affecte tous les processus de la physiologie et c'est un facteur clef de la distribution géographique des espèces. Les espèces se maintiennent dans les conditions environnementales qui ont permis leur adaptation. Les mortalités traduisent donc une rupture de l'adaptation ou une modification brutale de l'environnement qui peut affecter les équilibres qui se sont installés entre... |
Tipo: Text |
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Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00304/41537/40745.pdf |
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Fournier, Jonathan; Dupuy, Celie; Bouvy, Marc; Couraudon-reale, Marine; Charpy, Loic; Pouvreau, Stephane; Le Moullac, Gilles; Le Pennec, Marie-annick; Cochard, Jean-claude. |
In atoll lagoons of French Polynesia, growth and reproduction of pearl oysters are mainly driven by plankton concentration. However, the actual diet of black-lip pearl oysters P. margaritifera in these lagoons is poorly known. To fill this gap, we used the flow through chamber method to measure clearance rates of P. margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia). We found : (i) that pearl oysters cleared plankton at a rate that was positively related to plankton biovolume, (ii) that nanoflagellates were the main source of carbon for the pearl oysters, (iii) that the quantity and origin of carbon filtrated by pearl oysters was highly dependent on the concentration and composition of plankton. These results provide essential... |
Tipo: Text |
Palavras-chave: Pinctada margaritifera; Clearance rates; French Polynesia; Phytoplankton; Protists. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00078/18888/16599.pdf |
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Cuif, Jean-pierre; Burghammer, Manfred; Chamard, Virginie; Dauphin, Yannicke; Godard, Pierre; Le Moullac, Gilles; Nehrke, Gernot; Perez-huerta, Alberto. |
Consistently classified among the references for calcite simple prisms, the microstructural units that form the outer layer of the Pinctada margaritifera have been investigated through a series of morphological, crystallographical and biochemical characterizations. It is often said that the polygonal transverse shape of the prisms result from the competition for space between adjacent crystals. In contrast to this classical scheme the Pinctada prisms appear to be composed of four successive developmental stages from the concentrically growing disks on the internal side of the periostracum to the morphological, structural and compositional changes in both envelopes and mineral components at the end of the prisms. These latest structural and compositional... |
Tipo: Text |
Palavras-chave: Biomineralization; Bivalve shell; Microstructure; Calcite prisms. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00249/36039/34574.pdf |
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Sangare, Nathanael; Lo-yat, Alain; Le Moullac, Gilles; Pecquerie, Laure; Thomas, Yoann; Beliaeff, Benoit; Andrefouet, Serge. |
In French Polynesia black pearl farming represents one of the dominant business sectors. However, it still entirely relies on unpredictable Pinctada margaritifera spat collection success, which is itself conditioned by larval development completion. To assess the relationship between larval development and recruitment success, we studied under controlled conditions the effect of food concentration on development, growth, ingestion rate, survival and metabolic rate at the larval stage. Larvae were exposed to four different phytoplankton densities (2,5; 7,5; 15 and 30 cell.μL−1). Larvae survived equally all over the range of phytoplankton concentration with an average survival rate of 16% at the end of experiments. Food concentration significantly affected... |
Tipo: Text |
Palavras-chave: Bivalve larvae; Pinctada margaritifera; Physiology; Energetics; Dynamic energy budget theory; Pearl farming; Aquaculture. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00476/58795/61446.pdf |
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Latchere, Oihana; Mehn, Vincent; Gaertner-mazouni, Nabila; Le Moullac, Gilles; Fievet, Julie; Belliard, Corinne; Cabral, Philippe; Saulnier, Denis. |
Environmental parameters, such as food level and water temperature, have been shown to be major factors influencing pearl oyster shell growth and molecular mechanisms involved in this biomineralization process. The present study investigates the effect of food level (i.e., microalgal concentration) and water temperature, in laboratory controlled conditions, on the last stages of pearl mineralization in order to assess their impact on pearl quality. To this end, grafted pearl oysters were fed at different levels of food and subjected to different water temperatures one month prior to harvest to evaluate the effect of these factors on 1) pearl and shell deposition rate, 2) expression of genes involved in biomineralization in pearl sacs, 3) nacre... |
Tipo: Text |
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Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00428/54007/55223.pdf |
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Lacoste, Elise; Le Moullac, Gilles; Levy, Peva; Gueguen, Yannick; Gaertner-mazouni, Nabila. |
In bivalve aquaculture, dominant fouling organisms are filter feeders which can compete for food with reared bivalves, sometimes causing mortality or reducing their growth rate. This study investigated the effect of biofouling on the farmed pearl oyster Pinctada margaritifera in two lagoons of French Polynesia. Survival, growth and reproduction of 2 year-old pearl oysters were monitored with regular sampling schedules, from the initial stage of colonization up to 20 months of biofouling accumulation. Control groups of pearl oysters were kept free of biofouling as is the current practice in pearl farms. After more than a year of monitoring, no significant difference was recorded in shell growth rate between pearl oysters reared with epibionts and the... |
Tipo: Text |
Palavras-chave: Pearl oyster culture; Pinctada margaritifera; Biofouling; Growth; Reproduction. |
Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00201/31188/29587.pdf |
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Vahirua Lechat, I; Laure, F; Le Coz, Jean-rene; Bianchini, J; Bellais, M; Le Moullac, Gilles. |
The fatty acid and sterol composition of the oyster Pinctada margaritifera during oogenesis and in eggs was analysed. No major differences were observed during oogenesis, but the egg composition was significantly different from that of gonads. The amount of saturated fatty acids was the highest in eggs and the C16:0 predominant (P < 5%); by contrast, the amount of 22:6(n-3) was significantly lower (P < 5%) than in gonads. No major differences were observed for the polar lipid (PL) composition during oogenesis. The main free sterols in gonads and eggs were cholesterol and brassicasterol. Among free sterols, the proportion of cholesterol diminished continuously from the beginning to the end of gonad maturation, and this decrease persisted in eggs after... |
Tipo: Text |
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Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-5902.pdf |
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Linard, Clementine; Gueguen, Yannick; Moriceau, Jacques; Soyez, Claude; Hui, Belinda; Raoux, Aurore; Cuif, Jean Pierre; Cochard, Jean-claude; Le Pennec, Marcel; Le Moullac, Gilles. |
Marine mollusc shell growth has been widely measured using fluorochrome marking. In order to test the efficiency and reliability of calcein staining on P. margaritifera shells and pearls, the present study examined two administration methods, different concentrations and several immersion times.Immersion in a 150 mg.L-1 calcein solution for 12 h to 24 h appeared to be the best method for marking P. margaritifera shells. For pearl marking, injection of a 200 mg.L-1 calcein solution into the pearl pouch was the optimal method. Calcein marking was then used to measure the influence of food resource levels on the shell growth. Groups of 23-month-old P. margaritifera were fed at three trophic levels for two months. The two highest food levels tested (6 000... |
Tipo: Text |
Palavras-chave: Bivalvia; Pearl; Shell; Growth; Scanning electron microscope. |
Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00028/13907/11195.pdf |
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Le Moullac, Gilles; Boglio, Eric; Goarant, Cyrille. |
Une substance immunostimulante administrée par voie orale est testée chez la crevette Penaeus stylirostris. Cette expérimentation est réalisée à la station de St Vincent afin de se rapprocher des conditions du Syndrôme 93. Les effets sont mesurés pendant 2 semaines sur des paramètres hématologiques (hémocytes totaux, cellules à grands granules, coloration spécifique : cellules incorporant le rouge neutre). D'autre part un stress des crevettes en cage sur un fond réduit en bassin constitue le challenge. L'administration de l'immunostimulant par voie orale augmente significativement le nombre des hémocytes totaux, ainsi que les cellules incorporant le rouge neutre. Cependant le stress de la mise en cage sur fond réduit n'a pas déclenché de mortalité de type... |
Tipo: Text |
Palavras-chave: Penaeus stylirostris; Syndrome 93; Immunostimulant; Hémocyte; Stade de mue.. |
Ano: 1997 |
URL: https://archimer.ifremer.fr/doc/00680/79245/81762.pdf |
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Van Wormhoudt, Alain; Le Moullac, Gilles; Klein, Birgit; Sellos, Daniel. |
Las tripsinas, entre las proteasas, y las amilasas, entre las carbohidrasas, son las enzimas más activas en Penaeus vannamei, un camarón de interés comercial, especialmente en Latinoamérica. Estas enzimas y sus cDNAS fueron caracterizados. En lo que respecta a las tripsinas, se reconocieron cinco isoformas y se analizaron sus cDNAs correspondientes, los cuales codifican una preproenzima de 225 aminoácidos conteniendo un supuesto precursor peptídico de 14 residuos y una secuencia señal altamente hidrofobica de 14 aminoácidos. Dentro de la secuencia del zimogeno, se detectaron algunos sitios autocatalíticos (Int. J. Biochem. Cell Biol. 1996, 28, 551-563). Con respecto a las amilasas, dos isoformas fueron purificadas y caracterizadas; se hizo una selección en... |
Tipo: Text |
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Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00176/28726/27183.pdf |
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Ky, Chin-long; Le Moullac, Gilles. |
Size is the most important and valuable quality trait of cultured pearls produced by the black-lipped pearl oyster, Pinctada margaritifera. In French Polynesia, several breeding programmes have been started that aim to improve this size trait, which is highly related to shell growth rate in both recipient and donor oysters. Shell growth rate dictates the time of grafting, size of implanted nuclei and bio-mineralisation potential of the mantle and pearl sac. We assessed shell growth rate through routine digital shell biometric analysis on 22 hatchery families produced between 2005 and 2008. These included full-sib families and half-sib families derived from polyandry (one dam crossed with two or more sires). Results showed that: 1) a significant family... |
Tipo: Text |
Palavras-chave: Pinctada margaritifera; Pearl oyster; Hatchery-produced families; Growth performance; Shell diameter; Cultured pearl size. |
Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00387/49810/50384.pdf |
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Registros recuperados: 65 | |
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