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| Registros recuperados: 37 | |
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| Gagnaire, Beatrice; Thomas Guyon, H; Burgeot, Thierry; Renault, Tristan. |
| The shellfish industry is an important economic activity in France, occurring mostly in estuarine zones subject to pollution due to anthropogenic activities. The harmful effects of pollutants on species inhabiting these estuarine zones are not well known. Among marine species, bivalve mollusks---particularly Pacific oyster, Crassostrea gigas-may serve a model of interest. The species is sedentary and filter-feeding, which favors bioaccumulation of pollutants in their tissues. Oysters may be suitable for studies on disturbance by pollutants of physiological activities, among which defense mechanisms are poorly documented in bivalves. In this study, effects of pollutants on hemocyte functions were monitored in Pacific oyster, C. gigas. Hemocytes were exposed... |
| Tipo: Text |
Palavras-chave: Toxicity; Pesticides; PCBs; PAHs; Crassostrea gigas; Pacific oyster; Hemocytes; Flow cytometry; Cellular activities. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1695.pdf |
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| Soletchnik, Patrick; Ropert, Michel; Bedier, Edouard; Costil, K. S.; Dubois, Brice; Degremont, Lionel; Bouget, Jean-francois; Martin, Jean-louis; Enriquez-diaz, M.; Faury, Nicole; Le Moine, Olivier; Renault, Tristan; Gagnaire, Beatrice; Huvet, Arnaud; Moal, Jeanne; Samain, Jean-francois. |
| Field characterization of summer mortality was performed in France in the frame of the Morest project. Natural and hatchery spat were compared between three oyster production areas in France. Regardless of the natural or hatchery origin, oysters died during the reproduction period after temperature reaches 19 degree C. Thus, in southern areas, temperature accelerated gametogenesis of small spat (10mm) as well as adults, and mortality appeared for the two age classes. In contrast, sexual maturation proceeded more slowly in northern where spat mortality was lower compared to 18 months old oysters. However, critical gametogenesis and temperature were not sufficient to induce mortalities, as observed in examples with stable environment. Alternatively sediment... |
| Tipo: Text |
Palavras-chave: Seasonal variation; Oyster culture; Mortality causes; Hatcheries; Gametogenesis; Environmental factors; Crassostrea gigas; Oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3348.pdf |
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| Gagnaire, Beatrice; Soletchnik, Patrick; Madec, Patrick; Geairon, Philippe; Le Moine, Olivier; Renault, Tristan. |
| Summer mortality is an important economic concern for the Pacific oyster, Crassostrea gigas, industry all over the world and particularly in France. Outbreaks appear when oysters are in gonadal maturation. Bivalve defence mechanisms against pathogen invasion are assumed by circulating cells, the hemocytes. A field experiment was conducted in the Marennes-Oleron Basin (Charente-Maritime, France) in order to monitor hemocyte parameters, gametogenesis and mortality rates among C. gigas during 7 months from March to September 2002. Diploid (from natural bed and from hatchery) and triploid oysters were placed at 15 cm or 70 cm above sediment at Marennes-Oleron Basin. Triploid animals were included because they are considered as sterile animals. Mortality rates... |
| Tipo: Text |
Palavras-chave: Sexual maturation; Summer mortality; Triploids; Diploids; Flow cytometry; Hemocyte activities; Crassostrea gigas; Pacific oyster. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2923.pdf |
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| Nicolas, Jean-louis; Renault, Tristan; Gagnaire, Beatrice; Garcia, Celine; Le Roux, F; Miossec, Laurence; Pepin, Jean-francois; Saulnier, Denis. |
| L'un des objectifs principaux des travaux en pathologie des mollusques est d'identifier et d'étudier des agents infectieux capables d'induire des maladies et des mortalités chez les coquillages, en particulier, chez I'huître creuse, Crassostrea gigas, espèce principalement exploitée en France. Ces travaux semblent d'autant plus indispensables qu'il n'existait pas, jusqu'à ces dernières années, de maladies identifiées chez I'huître creuse en Europe excepté le virus herpès suspecté dès 1995 de provoquer des mortalités de naissain (Renault et al, 1995). Les principales maladies des espèces proches sont dues à des parasites comme Haplosporidium nelsoni (Ford et Heskin, 1987) et Perkinsus marinus Olivier et al, 1 998) pour Crassostrea virginica, Marteilia... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00304/41535/40743.pdf |
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| Bado-nilles, Anne; Auffret, Michel; Quentel, Claire; Le Floch, Stéphane; Arzel, Jacqueline; Gagnaire, Beatrice; Renault, Tristan; Thomas-guyon, Hélène. |
| Estuaries and coastal areas are often subjected to much pollution, including pesticides and polycyclic aromatic hydrocarbons (PAHs) produced by anthropic activities. Bay of Marennes-Oléron is an estuarine coastal zone in which there is a high level of aquacultural production and this has adverse effects in aquatic organisms. In fact, PAHs, which are widely spread throughout aquatic ecosystems, have a low polarity and so there is a clear tendency to bioaccumulate in marine organisms (1). The harmful effects of such contaminants on the organism's immune system, leading to a decreased resistance to pathogens, is a relatively new area of research and it still poorly understood. The aim of the present work was to detect the impact in vivo of PAHs on the immune... |
| Tipo: Text |
Palavras-chave: PaHs; Contamination; Crassostrea gigas; Oyster. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3428.pdf |
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| Morga, Benjamin; Arzul, Isabelle; Chollet, Bruno; Gagnaire, Beatrice; Renault, Tristan. |
| Bonamiosis is a disease affecting the flat oyster Ostrea edulis and caused by the protozoa parasite Bonamia ostreae, which is affiliated to the haplosporidia order and the cercozoa phylum. This parasite is mainly intracellular, infecting haemocytes, circulating cells playing an important role in the oyster's defence mechanisms. Even though the parasite's cycle has not been completely understood yet, direct infection from infected oysters to healthy oysters is possible. This leads us to think that there is no intermediary host in the cycle. Very little data on the parasite's infection mechanisms or the host's defence mechanisms is available. In order to better comprehend the Bonamia ostreae / host interaction, some flat oyster's haemocytes have been put in... |
| Tipo: Text |
Palavras-chave: Hémocytes; Ostrea edulis; Bonamia ostreae; Parasite; Huîtres. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3368.pdf |
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| Arzul, Isabelle; Bond, Celine; Gagnaire, Beatrice; Chollet, Bruno; Morga, Benjamin; Ferrand, Sylvie; Robert, Maeva; Renault, Tristan. |
| Bonamiosis due to the intrahaemocytic protistan parasite Bonamia ostreae is a European endemic disease affecting flat oysters Ostrea edulis. The parasite has been described in different ecosystems from estuaries to open sea and no clear correlations could be demonstrated between the development of the disease and environmental parameters such as temperature or salinity. The parasite life cycle, including its survival outside the host is not completely known. Nevertheless, the infection can be directly transmitted by cohabitation between infected and non infected oysters suggesting that the parasite does not need intermediate host to complete its cycle. In the present study, the impact of temperature and salinity on the survival of purified parasites... |
| Tipo: Text |
Palavras-chave: Effects; Temperarature; Salinity; Bonamia ostreae; Parasite; Pathology; Flat oyster; Ostrea edulis; Oyster. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3375.pdf |
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| Gagnaire, Beatrice; Duchemin, M; Auffret, Mathieu; Thomas-guyon, Helene; Renault, Tristan. |
| Parameters of hemocyte populations have been considered as relevant indicators of bivalve health and are currently used in immunotoxicological studies. Hemocytes in hemolymph can be collected by puncturing either the pericardial cavity or the adductor muscle sinus with a syringe. Flow cytometry is a methodological approach that is increasingly being used in laboratories for the study of hemocyte parameters in aquatic invertebrates. However, various protocols for hemocyte processing in laboratories equipped with different types of cytometers have been published. In this context, two flow cytometers ( EPICS XL4 (R), Beckman Coulter and FacsCalibur (R), Becton Dickinson) and two sites of hemocyte collection ( pericardial cavity and adductor muscle sinus) were... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Phagocytosis; Hemocytes; Flow cytometry. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3898.pdf |
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| Delaporte, Maryse; Moal, Jeanne; Soudant, Philippe; Lambert, Christophe; Pouvreau, Stephane; Enriquez, Martha; Degremont, Lionel; Soletchnik, Patrick; Gagnaire, Beatrice; Ropert, Michel. |
| In the frame of MOREST project, a common biological material, resulting of a mixture of different families produced in experimental hatchery, was reared in two different environmental fields : Normandy and Charente. Concomitantly, a pool was conditioned at the Ifremer Argenton hatchery with three different algae levels : 4%, 8% and 12% of algal dry weight per oyster dry weight. During the experiments, five immune parameters were studied in parallel with survival rate and reproductive status (stages and intensity). Site location, seasonal variations and experimental diet level clearly influenced oyster immune parameters. Haemocyte counts were higher for oysters reared in Normandy than those reared in Charente and in hatchery. Granulocyte percentage was... |
| Tipo: Text |
Palavras-chave: Defense mechanisms; Nutrition; Seasonal variations; Physiology; Crassostrea gigas; Pacific oysters. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/acte-3500.pdf |
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| Bouilly, Karine; Gagnaire, Beatrice; Bonnard, Marc; Thomas-guyon, Helene; Renault, Tristan; Miramand, Pierre; Lapegue, Sylvie. |
| Pacific oysters, Crassostrea gigas, are commonly reared in estuaries where they are exposed to anthropogenic pollution. Much research has been made on the toxicity of cadmium to aquatic organisms because the compound recurrently contaminates their environment. Our study examined the influence of cadmium on aneuploidy level (lowered chromosome number in a percentage of somatic cells) and hemocyte parameters in C. gigas at different stages of life. Adults and juveniles were exposed to two different concentrations of cadmium. The first concentration applied was equivalent to a peak value found in Marennes-Oleron bay (Charente-Maritime, France; 50 ng L-1) and the second was 10 times higher (500 ng L-1). Exposure to 50 ng L-1 cadmium caused a significant... |
| Tipo: Text |
Palavras-chave: Phenoloxidase; Flow cytometry; Hemocytes; Aneuploidy; Crassostrea gigas; Cadmium. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1687.pdf |
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| Renault, Tristan; Soletchnik, Patrick; Le Moine, Olivier; Faury, Nicole; Guilpain, Patrice; Geairon, Philippe; Razet, Daniel; Seugnet, Jean-luc; Gagnaire, Beatrice; Kerdudou, Nolwenn. |
| Massive abnormal mortalities of flat oysters Crassostrea during the summer period are nothing new, and such episodes have been described in scientific literature for about forty years. Numerous studies demonstrate that there is not one single identified cause to this phenomenon and that it is, on the contrary, a combination of different parameters. This program proposes a multidisciplinary approach to the problem of summer mortality of C. gigas in which the working hypothesis is that these mortalities result from the interaction of three parameters: environment, host and pathogens. As a consequence, this program gathers all the necessary competences for the study of these interactions: competences in genetics, physiology, immunology, ecotoxicology,... |
| Tipo: Text |
Palavras-chave: Marennes Oléron; Activité hémoctyaire; Synergie écologie côtière; Pathologie; Paramètres hémocytaires; Physiologie; Paramètres; Reproduction; Mortalités; Crassostrea gigas; Huîtres. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/acte-3404.pdf |
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| Faucet, Jerome; Maurice, Manuelle; Gagnaire, Beatrice; Renault, Tristan; Burgeot, Thierry. |
| As the marine mussel Mytilus edulis is commonly used as a sentinel species, it would be useful to develop a primary culture of the target organs most often in contact with the marine environment. This study reports an improved method for dissociating the digestive gland and gills of M. edulis and considers the effect of mussel storage on cell viability and functionality before culture initiation. Viability and enzymatic activities such as those of esterase and peroxidase were monitored by flow cytometry, a sensitive, objective technique allowing large volumes of cells to be counted within a short time. A primary culture of digestive gland showed more than 75% viability after 72 h. Mussels were maintained in an aquarium containing clean, oxygenated seawater... |
| Tipo: Text |
Palavras-chave: Mytilus edulis; Gill; Flow cytometry; Digestive gland; Cell culture. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-936.pdf |
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| Samain, Jean-francois; Degremont, Lionel; Soletchnik, Patrick; Haure, Joel; Bedier, Edouard; Ropert, Michel; Moal, Jeanne; Huvet, Arnaud; Bacca, Helene; Van Wormhoudt, A; Delaporte, Maryse; Costil, K; Pouvreau, Stephane; Lambert, Christian; Boulo, Viviane; Soudant, Philippe; Nicolas, Jean-louis; Leroux, Frederique; Renault, Tristan; Gagnaire, Beatrice; Geret, Florence; Boutet, Isabelle; Burgeot, Thierry; Boudry, Pierre. |
| Summer mortality of Pacific oysters is known in several countries. However no specific pathogen has been systematically associated with this phenomenon. A complex combination of environmental and biological parameters has been suggested as the cause and is now starting to be identified. A high genetic basis was found for survival in oysters when a first generation (G1) was tested in three sites during summer. This paper presents a synthesis on physiological characteristics of two selected groups ('R' and 'S', from families selected for resistance and susceptibility to summer mortality respectively), of the second and third generations. R and S showed improvement or reduction of survival compared with the control in both field and laboratory trials... |
| Tipo: Text |
Palavras-chave: ROS; Temperature; Stress; Hemocytes; Reproduction; Genetic selection; Resistant oyster; Crassostrea gigas; Pacific Oyster; Summer mortality. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2809.pdf |
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| Gagnaire, Beatrice; Gay, Melanie; Huvet, Arnaud; Daniel, Jean-yves; Saulnier, Denis; Renault, Tristan. |
| To assess the impact of pollution induced by pesticides on Pacific oyster, Crassostrea gigas, health in France, in vivo effects of combined pesticide exposure and bacterial challenge on cell activities and gene expression in hemocytes were tested using flow cytometry and real-time PCR. As a first step, an in vivo model of experimental contamination was developed. Pacific oysters were exposed to a mixture of eight pesticides (atrazine, glyphosate, alachlor, metolachlor, fosetyl-alumimium, terbuthylazine, diuron and carbaryl) at environmentally relevant concentrations over a 7-day period. Hemocyte parameters (cell mortality, enzyme activities and phagocytosis) were monitored using flow cytometry and gene expression was evaluated by real-time PCR (RT-PCR).... |
| Tipo: Text |
Palavras-chave: Gene expression; Flow cytometry; Vibrio splendidus; Pathogenesis; Phagocytosis; Hemocyte; Pesticides; Bivalve immunity; Crassostrea gigas; Pacific oyster. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3022.pdf |
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| Registros recuperados: 37 | |
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