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| Registros recuperados: 49 | |
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| Nicolas, Jean-louis; Basuyaux, Olivier; Mazurie, Joseph; Thebault, Anne. |
| Since 1997, mass mortality of the abalone Haliotis tuberculata L. has occurred in the natural environment along the French coast. The outbreak of disease started on the south coast of Brittany near Concarneau in 1997, then spread to the north of Brittany (in 1998) and the west coast of Normandy (Golfe de St. Malo in 1999). Between 60 and 80% of the abalone died. In 1999, mortality also affected a land-based abalone farm in Normandy during the summer. At this farm, a Vibrio sp. was isolated in abundance from abalone that had just died. The disease was experimentally reproduced by inoculation or by introducing the pathogen into the surrounding water. This vibrio, identified by genotypic and phenotypic characters, is related to V carchariae. It is similar to... |
| Tipo: Text |
Palavras-chave: Pathogenicity; Bacterial epizootic; Vibrio carchariae; Haliotis tuberculata. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-2795.pdf |
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| Andrieux, Francoise; Azandegbe, Afi; Caradec, Florian; Philippon, Xavier; Kerouel, Roger; Youenou, Agnes; Nicolas, Jean-louis. |
| This study aims to compare the impact of oyster cultures on diagenetic processes and the phosphorus cycle in the sediments of the Aber Benoît and the Rivière d’Auray, estuary of Brittany, France. Our results showed clear evidence of the seasonal impact of oyster cultures on sediment characteristics (grain size, organic matter parameters), and the phosphorus cycle, especially in the Aber Benoît. At this site, seasonal variations of sulfide and Fe concentrations in pore waters, as well as Fe-P concentrations in the solid-phase highlighted a shift from a system governed by iron reduction (Reference) to a system governed by sulphate reduction (Beneath Oyster). This could be partly explained by the increase in labile organic matter (ie, biodeposits) beneath... |
| Tipo: Text |
Palavras-chave: Sediment; Phosphorus; Sulfide; Dissolved Fe/P ratios; Labile organic matter; Oyster cultures. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00209/32003/30441.pdf |
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| Genard, Bertrand; Miner, Philippe; Nicolas, Jean-louis; Moraga, Dario; Boudry, Pierre; Pernet, Fabrice; Tremblay, Rejean. |
| Background: Bacterial infections are common in bivalve larvae and can lead to significant mortality, notably in hatcheries. Numerous studies have identified the pathogenic bacteria involved in such mortalities, but physiological changes associated with pathogen exposure at larval stage are still poorly understood. In the present study, we used an integrative approach including physiological, enzymatic, biochemical, and molecular analyses to investigate changes in energy metabolism, lipid remodelling, cellular stress, and immune status of Crassostrea gigas larvae subjected to experimental infection with the pathogenic bacteria Vibrio coralliilyticus. Findings: Our results showed that V. coralliilyticus exposure induced (1) limited but significant increase... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00144/25504/23662.pdf |
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| Castex, Mathieu; Chim, Liet; Pham, Dominique; Lemaire, Pierrette; Wabete, Nelly; Nicolas, Jean-louis; Schmidely, P; Mariojouls, C. |
| We studied the effects of a lactic acid bacterium, Pediococcus acidilactici (strain MA 18/5M, CNCM), as a dietary probiotic on growth performance and some nutritional and microbiological aspects of the shrimp Litopenaeus stylirostris. Experimental shrimp culture was carried out over 10 weeks, using floating cages of 14 m(2) each set in earthen ponds, in a New Caledonia farm affected by "Summer syndrome", a septicaemic vibriosis caused by Vibrio nigripulchritudo. The experiment design testing probiotic-coated pellets against control was replicated in two earthen ponds. High mortalities, characteristic of Summer syndrome, were observed during the first 2 weeks of the trial. The probiotic improved production in the treated cages from both ponds with increases... |
| Tipo: Text |
Palavras-chave: Vibriosis; Floating cages; Litopenaeus stylirostris; Pediococcus acidilactici; Probiotic. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4079.pdf |
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| Cochennec-laureau, Nathalie; Baud, Jean-pierre; Bedier, Edouard; Boudry, Pierre; Huvet, Arnaud; Nicolas, Jean-louis; Pepin, Jean-francois; Petton, Bruno. |
| Ce bilan comprend deux parties : la première est dédiée à une synthèse des travaux présentés lors des journées « Surmortalités des huîtres creuses, Crassostrea gigas » les 8 et 9 décembre 2009 et, la seconde partie, à une proposition d'un projet de recherche spécifique 2010-2012 en complément des propositions de « sortie de crise ». Contexte Les mortalités estivales de l'huître creuse, Crassostrea gigas, sont décrites depuis une vingtaine d'années en France mais également au Japon, en Corée, aux USA et en Australie. Ces phénomènes ou « syndrome des mortalités estivales » ont fait l'objet d'une étude pluridisciplinaire en France entre 2001 et 2006 (Défi MOREST). Toutefois, en 2008 et 2009, l'ostréiculture française a du faire face à deux épisodes de... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/2010/acte-7393.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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| Huvet, Arnaud; Royer, J.; Moal, J.; Burgeot, Thierry; Lapègue, Sylvie; Boulo, Viviane; Nicolas, Jean-louis; Lambert, C.. |
| Les résultats du programme MOREST démontrent l'existence d'une composante génétique à la survie estivale du naissain et nous permettent de disposer aujourd'hui d'huTtres « résistantes» (R) et « susceptibles» (S) aux mortalités estivales (Dégremont et aL, 2002, 2005). La forte héritabilité estimée face à un tel système multifactoriel permet de suspecter que le caractère sélectionné puisse être gouverné par un ou un trés petit nombre de gènes sur une région chromosomique donnée. D'après le modèle d'interaction suspecté entre l'environnement, l'huître et des pathogènes opportunistes, une hiérarchie des facteurs, conduisant aux mortalités, permet de montrer qu'aucun d'entre eux ne peut provoquer à lui seul les mortalités mais que leur combinaison est... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/00306/41706/40917.pdf |
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| Lambert, Christian; Nicolas, Jean-louis; Bultel, Valérie. |
| Using a chemiluminescence (CL) test, it had been previously demonstrated that Vibrio pectenicida, which is pathogenic to Pecten maximus larvae, was able to inhibit completely the CL activity of P, maximus hemocytes and partially inhibit those of Crassostrea gigas, Conversely, a Vibrio sp, strain, S322, pathogenic to C,gigas larvae was more active in reducing the CL activity of oyster hemocytes than of scallop hemocytes, Using this same CL biotest, V, pectenicida and S322 cytoplasmic extracts were shown to reproduce CL inhibition while the cytoplasmic extract of a nonpathogenic strain (U1, Pseudoalteromonas) was without effect. Moreover, cytoplasmic extract as well as live V, pectenicida cells provoked, within a few hours, death of P. maximus hemocytes... |
| Tipo: Text |
Palavras-chave: Bivalves; Hemocyte; Toxin; Chemiluminescence; Crassostrea gigas; Pecten maximus; Vibrio pectenicida. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-466.pdf |
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| Person-le Ruyet, Jeanine; Baudin-laurenc, Félix; Devauchelle, Nicole; Metailler, Robert; Nicolas, Jean-louis; Robin, Jean; Guillaume, Jean. |
| Turbot, Scophthalmus maximus Rafinesque, 1810: Psetta maxima Linnaeus, 1758, is a marine demersal carnivorous flatfish of the Scophthalmidae family, relatively abundant in Europe: from 68°N down to Morocco 30°N. It is also abundant in the Mediterranean Sea as far as Turkey. But it is lacking in the Black Sea, where two very close species, S. maeoticus and S. ponticus, are naturally found (Figure 1). Turbot are caught on sand, gravel, or mixed bottoms at a depth of 20 to 70 m. The total annual catch is less than 10,000 for all Europe in spite of the high market price: from 10 to 25 U.S. $/kg according to the country and the size of the fish (0.65 to 15 kg). Turbot was selected for aquaculture in the early 1970s, both in the United Kingdom and France due to... |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00048/15930/13356.pdf |
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| Asmani, Katia; Petton, Bruno; Le Grand, Jacqueline; Mounier, Jerome; Robert, Rene; Nicolas, Jean-louis. |
| The first aim of this study was to determine the stocking density limits for Pacific oyster Crassostrea gigas larvae reared in flow-through system (FTS) and recirculating aquaculture systems (RAS). The second aim was to examine biofilm formation on the larval tank wall and its interaction with larvae growth. Three larvae concentrations were tested: 50, 150, and 300 mL−1. Chemical parameters and larvae performance were measured. The biofilm was observed by scanning electron microscopy, and its bacterial composition was investigated by pyrosequencing analysis of part of the 16S rRNA gene. The highest growth (13 µm day–1), survival (87%) and metamorphosis (50%) rates were observed in FTS at 50 larvae mL–1, while lower and similar performances occurred at... |
| Tipo: Text |
Palavras-chave: Pacific oyster; Larval culture; High stocking density; Biofilm; Filamentous bacteria. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50611/51324.pdf |
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| Nicolas, Jean-louis; Ansquer, Dominique; Cochard, Jean-claude. |
| A bacterial strain belonging to the genus Vibrio was involved in a recurrent outbreak of disease in Manila clam Tapes philippinarum larvae at a commercial hatchery, This vibrio, named VTP for convenience, was not related to the known pathogenic vibrios and possessed unusual characteristics, Only Manila clam larvae and postlarvae were affected by the disease, Oyster and scallop larvae were not affected by vrp, Survival of vrp was found to be of short duration in seawater but even a very small number of cells (1 cell per 5 ml) could initiate the disease, VTP did not grow on thiosulfate-citratebile-sucrose agar and was resistant to chloramphenicol. An epidemiological study utilizing bioassays revealed the presence of VTP in adult bivalves and in the... |
| Tipo: Text |
Palavras-chave: Bacterial diseases; Clam culture; Larvae; Pathogenic bacteria; Tapes philippinarum; Vibrio. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00037/14872/12198.pdf |
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| Garnier, Matthieu; Labreuche, Yannick; Nicolas, Jean-louis. |
| Eleven Vibrio isolates invading the hemolymph of live and moribund oysters (Crassostrea gigas) collected in the field and from a hatchery in France, were characterized by a polyphasic approach. Phylogenetic analysis of 16S rRNA, gyrB and toxR genes indicated high homogeneity between these strains and the Vibrio aestuarianus type strain (ATCC35048(T)), and confirmed previous 16S rRNA analysis. In contrast, DNA:DNA hybridization was from 61% to 100%, while phenotypic characters and virulence tests showed a large diversity between the strains. Nevertheless, several common characters allowed the isolates to be distinguished from the reference strain. On the basis of several distinct phenotypic characteristics, it is proposed to establish two subspecies within... |
| Tipo: Text |
Palavras-chave: Polyphasic approach; Summer mortalities; Crassostrea gigas; Pathogen; French isolates; Vibrio aestuarianus. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4961.pdf |
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| Labreuche, Yannick; Lambert, Christophe; Soudant, Philippe; Boulo, Viviane; Huvet, Arnaud; Nicolas, Jean-louis. |
| The strategies used by bacterial pathogens to circumvent host defense mechanisms remain largely undefined in bivalve molluscs. In this study, we investigated experimentally the interactions between the Pacific oyster (Crassostrea gigas) immune system and Vibrio aestuarianus strain 01/32, a pathogenic bacterium originally isolated from moribund oysters. First, an antibiotic-resistant V. aestuarianus strain was used to demonstrate that only a limited number of bacterial cells was detected in the host circulatory system, suggesting that the bacteria may localize in some organs. Second, we examined the host defense responses to V. aestuarianus at the cellular and molecular levels, using flow-cytometry and real-time PCR techniques. We showed that hemocyte... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Oyster; Pathogenesis; Vibrio aestuarianus; Bivalve immunity. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2182.pdf |
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| Labreuche, Yannick; Le Roux, Frederique; Henry, Joel; Zatylny, Celine; Huvet, Arnaud; Lambert, Christophe; Soudant, Philippe; Mazel, Didier; Nicolas, Jean-louis. |
| Extracellular products (ECPs) of the pathogenic Vibrio aestuarianus 01/32 were previously reported to display lethality in Crassostrea gigas oysters and to cause morphological changes and immunosuppression in oyster hemocytes. To identify the source of this toxicity, biochemical and genetic approaches were developed. ECP protease activity and lethality were shown to be significantly reduced following incubation with metal chelators, suggesting the involvement of a zinc metalloprotease. An open reading frame of 1836 bp encoding a 611-aa metalloprotease (designated yam) was identified. The deduced protein sequence showed high homology to other Vibrio metalloproteases reported to be involved in pathogenicity. To further confirm the role of this enzyme in ECP... |
| Tipo: Text |
Palavras-chave: Vibrio aestuarianus; Metalloprotease; Crassostrea gigas; Oyster; Hemocytes; Extracellular products. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00015/12649/9588.pdf |
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| Choquet, Gwenaelle; Soudant, P; Lambert, C; Nicolas, Jean-louis; Paillard, C. |
| Vibrio tapetis is the causative agent of brown ring disease (BRD), which affects a species of clam, Ruditapes philippinarum. After incubation with V. tapetis, hemocytes lose filopods and become rounded, indicating cytotoxic activity of the bacterium. To rapidly quantify this cytotoxicity, a flow-cytometry test was developed based on the capacity of V tapetis to inhibit adhesion of clam hemocytes to plastic. Several bacteria:hemocyte ratios, the cytotoxicity of other Vibrio spp. pathogenic to bivalves, and that of various V. tapetis isolates were tested. Inhibition of adherence is detectable with as few as 5 bacteria per hemocyte. The greater cytotoxic activity of V tapetis compared to that of V splendidus and V pectenicida suggests a specific pathogenicity... |
| Tipo: Text |
Palavras-chave: Cytotoxicity; Flow cytometry; Vibrio tapetis; Ruditapes philippinarum; Bivalve hemocytes; Pathogenicity. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/00000/10761/7590.pdf |
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| Nicolas, Jean-louis; Corre, S; Gauthier, Gilles; Robert, Rene; Ansquer, Dominique. |
| Scallop Pecten maximus larvae have been cultured at the Argenton and Tinduff (Brittany, France) hatcheries with antibiotic treatment (chloramphenicol at 8 ppm) for 15 yr. Without treatment, outbreak of disease has normally occurred between Day 12 and Day 19 or sometimes earlier. A bacteriological study of larvae reared with and without antibiotic was performed over a 4 yr period. Among the collected strains, 2 clusters (C and F) of vibrios were present at high densities only in larvae cultured without treatment. One cluster (C) was routinely isolated over the 4 yr of study, while the other (F) was collected only in the third year. Their virulence with respect to scallop larvae and their lack of infectivity with respect to oyster larvae were demonstrated in... |
| Tipo: Text |
Palavras-chave: Larvae; Bivalve; Vibrio; Scallop. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00090/20077/17716.pdf |
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| Kesarcodi-watson, Aditya; Miner, Philippe; Nicolas, Jean-louis; Asmani, Katia; Robert, Rene. |
| During a series of experiments, bacteriological elements in scallop larval rearing were investigated: larvae susceptibility to pathogens as a function of their age, and the use of probiotic bacteria during larviculture. Younger larvae (d5 PF) were highly more susceptible to pathogenic-challenge than their older siblings, which were challenged at an older age (d15 PF). A challenge with 104 CFU mL−1 of V. pectenicida killed 100% of d5 PF larvae 7 days following challenge, yet killed only 9% of d15 PF larvae 9 days following challenge. Use of the probiotics Phaeobacter gallaeciensis, Alteromonas macleodii 0444 and Neptunomonas sp. 0536, provided for larger larvae, a high yield of competent larvae and, perhaps more importantly, protection against... |
| Tipo: Text |
Palavras-chave: Scallop; Pecten maximus; Probiotics; Alteromonas macleodii; Neptunomonas; Phaeobacter. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00210/32153/30900.pdf |
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| Garnier, Matthieu; Labreuche, Yannick; Garcia, Celine; Robert, Maeva; Nicolas, Jean-louis. |
| A study was conducted to investigate the involvement of bacteria in oyster mortalities during summer. Moribund and apparently healthy oysters were sampled during mortality events along the French coast and in rearing facilities, usually when temperature reached 19 degrees C or higher, and oysters were in the gonadal maturation phase. Hemolymph samples were aseptically withdrawn and submitted to bacteriological analysis. In healthy oysters, bacteria colonized hernolymph at low concentrations depending on the location. In most moribund oysters, bacteria were present in hemolymph and other tissues. These bacterial populations were more often diverse in oysters originating from the open sea than from facilities where animals were generally infected by a single... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2406.pdf |
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| Registros recuperados: 49 | |
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