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| Registros recuperados: 65 | |
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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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| 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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| 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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| Burgeot, Thierry; Gagnaire, Beatrice; Renault, Tristan; Haure, Joel; Moraga, D.; David, E.; Boutet, L.; Sauriau, P.g.; Malet, Nathalie; Bouchet, V.; Lapegue, Sylvie; Bouilly, Karine; Le Moullac, Gilles; Arzul, Genevieve; Knoery, Joel; Quiniou, Francoise; Bacher, Cedric; Soletchnik, Patrick. |
| Les mortalités d'huîtres observées sur les côtes françaises apparaissent principalement à proximité du sédiment et pendant la gamétogenèse. Les interactions de facteurs environnementaux sur les écosystèmes conchylicoles comme la température, les apports des bassins versants et le compartiment sédimentaire illustrent un risque de mortalité lié à différentes sources de stress (Thème 1). Les variations de la qualité de la ressource trophique pendant l'effort de gamétogenèse favorise une baisse de l'énergie disponible (Thème 2) et contraint l'organisme fragilisé à fournir un effort d'adaptation (Fent 2004). L'apparition d'un stress pendant cette période sensible des huîtres pourrait constituer un facteur aggravant de mortalité. L'objectif de cette étude est... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00304/41538/40746.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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| 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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| Gueguen, Yannick; Montagnani, Caroline; Joubert, Caroline; Marie, Benjamin; Belliard, Corinne; Tayale, Alexandre; Fievet, Julie; Levy, Peva; Piquemal, David; Marin, Frederic; Le Moullac, Gilles; Ky, Chin-long; Garen, Pierre; Lo, Cedrick; Saulnier, Denis. |
| Tahiti’s pearl farming industry plays a major socio-economic role in French Polynesia. In an increasingly competitive market where the production of high quality pearls becomes essential, research can help secure and ensure sustainable production. In that context, Ifremer, in close collaboration with the “direction des resources marines” (French Polynesian government agency) has developed research projects on the “sustainable development of pearl farming”. This program is organized along 3 axes: (1) understanding the animal physiology and initiating a genetically selective breeding program of donor oysters; (2) understanding pearl oyster larvae dispersal and recruitment; (3) understanding the molecular mechanisms underlying biomineralization processes... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Biomineralization; Pinctada margaritifera. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00167/27840/26049.pdf |
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| Le Moullac, Gilles; Goraguer, Herle; Maihota, Mayalen; Teissier, Hinano; Tiapari, Jerome; Bennett, Auguste; Soyez, Claude. |
| Dans le cadre du programme Reproduction de l’huître perlière Pinctada margaritifera, dont l’objectif est la maîtrise des croisements, le conditionnement en laboratoire des reproducteurs est une étape nécessaire pour espérer contrôler et synchroniser la maturation de ces reproducteurs. Les facteurs présumés qui permettront de contrôler la maturation sont d’ordre environnemental : l’alimentation et la température. Cependant avant d’espérer établir la relation entre la fonction physiologique et les facteurs qui contrôlent cette fonction, il est indispensable de mettre en œuvre une zootechnie adaptée aux besoins vitaux de façon à assurer la survie et une bonne croissance. Cette étude a pour objectif de tester la survie et la croissance des huîtres perlières... |
| Tipo: Text |
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| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00182/29288/27729.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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| Le Moullac, Gilles; Cheize, Marie; Gastineau, Olivier; Daniel, Jean-yves; Le Coz, Jean-rene; Huvet, Arnaud; Moal, Jeanne; Pouvreau, Stephane; Van Wormhoudt, A; Samain, Jean-francois. |
| The purpose of this study is to examine the response of the oyster Crassostrea gigas to sulphide at different biological scales. A first experiment was designed to measure for 20 h the clearance (CR) and oxygen consumption (OC) rates of oysters exposed at different concentrations of sulphide (0, 3, 6, 12, 20, and 40 mu M). The second experiment was carried out to evaluate the metabolic adaptations to chronic sulphide exposure for 10 days by measuring PK and PEPCK enzyme activities, succinate and alanine content, the adenylate energy charge (AEC), and the activity of the electron transport system (ETS)in whole oysters at above 20 mu M. PK and PEPCK mRNAs and enzyme activities have been measured in adductor muscle. When exposed to sulphide above 20 mu M, CR... |
| Tipo: Text |
Palavras-chave: ATP; AEC; Electron transport system; Succcinate; Alanine; Phosphoenolpyruvate carboxykinase; Pyruvate kinase; Oxygen consumption; Clearance rate; Crassostrea gigas; Sulphide; Oyster. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3924.pdf |
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| Le Moullac, Gilles; Hui, Belinda; Vonau, Vincent; Levy, Peva; Cochard, Jean-claude. |
| Preliminary experiments allowed defining basic requirements of Pinctada margaritifera for somatic and gonadic growth in controlled conditions. This study was continued by observation of the gametogenesis at a cellular level. In April/May 2008, 125 oysters were conditioned for 30 days in 25 tubular tanks (30 L). Water was renewed 4 times/hour. A mixed (v:v) diet of Isochrysis galbana (T-Iso) and Chaetoceros gracilis was supplied continuously. A control batch of 125 oysters was maintained in trays in the lagoon. An initial sample of 30 individuals was made. Gonadic changes were first characterized using a gonadal development index (GDI) based on the ratio of the gonad area to the total visceral mass area on a sagittal section of the body. Histological... |
| Tipo: Text |
Palavras-chave: Pearl oyster; Reproduction; Gametogenesis; Broodstock. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00029/14010/11196.pdf |
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| Teaniniuraitemoana, Vaihiti; Lepretre, Maxime; Levy, Peva; Vanaa, Vincent; Parrad, Sophie; Gaertner-mazouni, Nabila; Gueguen, Yannick; Huvet, Arnaud; Le Moullac, Gilles. |
| The black-lip pearl oyster Pinctada margaritifera is a protandrous hermaphrodite species. Its economic value has led to the development of controlled hatchery reproduction techniques, although many aspects remain to be optimized. In order to understand reproductive mechanisms and their controlling factors, two independent experiments were designed to test hypotheses of gametogenesis and sex ratio control by environmental and hormonal factors. In one, pearl oysters were exposed under controlled conditions at different combinations of temperature (24 and 28°C) and food level (10,000 and 40,000 cells mL−1); whereas in the other, pearl oysters were conditioned under natural conditions into the lagoon and subjected to successive 17β-estradiol injections (100 μg... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00285/39638/38184.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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| Registros recuperados: 65 | |
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