|
|
|
|
|
| Moreau, Pierrick. |
| The thesis work is part of the very current issue on mass mortality outbreaks affecting Pacific oyster, C. gigas, spat and juveniles and questions about the involvement of pesticides in this phenomenon. The first part of this thesis was devoted to study the effects of pesticides on hemocyte parameters in the Pacific oyster (in vitro and in vivo). The immunomodulator effect of selected pesticides (alone or in mixture) has been explored principally through flow cytometry. The second part concerned the study of the effects of a pesticides mixture on OsHV-1 itself. No direct effects have been reported on the viral particles in presence of the pollutants. Moreover, pesticide effects on Pacific oysters were also explored through experimental pathology assays... |
| Tipo: Text |
Palavras-chave: Pacific oyster; Pesticides; OsHV-1; Autophagy; Immunity; Hemocyte; Pathology. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00226/33740/32149.pdf |
| |
|
|
| Moreau, Pierrick; Faury, Nicole; Burgeot, Thierry; Renault, Tristan. |
| Since 2008, mass mortality outbreaks have been reported in all French regions producing Pacific oysters, and in several Member States of the European Union. These mass mortality events of Pacific oysters are related to OsHV-1 infection. They occur during spring and summer periods leaving suspect the quality of the marine environment and the role of seasonal use of pesticides associated with the arrival of freshwater in oyster rearing areas. Pesticides have been also detected in French coastal waters, especially in areas of oyster production. Using PMA real-time PCR we showed that a mixture of 14 pesticides has no effect on the integrity of virus capsids from viral suspension in the conditions tested. A contact of oysters with this pesticide mixture was... |
| Tipo: Text |
|
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00273/38405/36730.pdf |
| |
|
|
| Moreau, Pierrick; Moreau, Kevin; Morga, Benjamin; Tourbiez, Delphine; Travers, Marie-agnes; Rubinsztein, David; Renault, Tristan. |
| Mass mortality outbreaks of Pacific oysters, Crassostrea gigas, are reported in different areas around the world affecting seriously the shellfish aquaculture sector. Two pathogens are associated with these mortality outbreaks, ostreid herpesvirus 1 (OsHV-1) and Vibrio aestuarianus. In this contexte, a better knowledge is needed in terms of oyster immunity. For this purpose, as an important degradation pathway autophagy was investigated in the Pacific oysters. An in silico research of genes involved in autophagy using the C. gigas genome allowed identification of homologs of ATG1 and ATG8/LC3(Microtubule-associated protein 1A/1B-light chain 3). Gene expression and protein detection were analysed using real-time PCR and western blot, respectively. ATG1 and... |
| Tipo: Text |
Palavras-chave: Autophagy; Pacific oyster; Crassostrea gigas; OsHV-1; Vibrio aestuarianus. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00218/32876/31345.pdf |
| |
|
|
| Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan. |
| Pollutants via run-off into the ocean represent a potential threat to marine organisms, especially bivalves such as oysters living in coastal environments. These organisms filter large volumes of seawater and may accumulate contaminants within their tissues. Pesticide contamination in water could have a direct or indirect toxic action on tissues or cells and could induce alteration of immune system. Bivalve immunity is mainly supported by hemocytes and participates directly by phagocytosis to eliminate pathogens. Some studies have shown that pesticides can reduce immune defences and/or modify genomes in vertebrates and invertebrates. Metaldehyde is used to kill slugs, snails and other terrestrial gastropods. Although metaldehyde has been detected in... |
| Tipo: Text |
Palavras-chave: Immunity; Hemocytes; Metaldehyde; Pacific oyster; Flow cytometry; In vivo; Genetic diversity. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00195/30602/29059.pdf |
| |
|
|
| Renault, Tristan; Tchaleu, Gwenaelle; Faury, Nicole; Moreau, Pierrick; Segarra, Amelie; Barbosa-solomieu, Valerie; Lapegue, Sylvie. |
| Ostreid herpesvirus 1 (OsHV-1) is a DNA virus belonging to the Malacoherpesviridae family from the Herpesvirales order. OsHV-1 has been associated with mortality outbreaks in different bivalve species including the Pacific cupped oyster, Crassostrea gigas. Since 2008, massive mortality events have been reported among C. gigas in Europe in relation to the detection of a variant of OsHV-1, called μVar. Since 2009, this variant has been mainly detected in France. These results raise questions about the emergence and the virulence of this variant. The search for association between specific virus genetic markers and clinical symptoms is of great interest and the characterization of the genetic variability of OsHV-1 specimens is an area of growing interest.... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00172/28306/26582.pdf |
| |
|
|
| Renault, Tristan; Moreau, Pierrick; Faury, Nicole; Pepin, Jean-francois; Segarra, Amelie; Webb, Stephen. |
| Although there are a number of ostreid herpesvirus 1 (OsHV-1) variants, it is expected that the true diversity of this virus will be known only after the analysis of significantly more data. To this end, we analyzed 72 OsHV-1 "specimens" collected mainly in France over an 18-year period, from 1993 to 2010. Additional samples were also collected in Ireland, the United States, China, Japan, and New Zealand. Three virus genome regions (open reading frame 4 [ORF4], ORF35, -36, -37, and -38, and ORF42 and -43) were selected for PCR analysis and sequencing. Although ORF4 appeared to be the most polymorphic genome area, distinguishing several genogroups, ORF35, -36, -37, and -38 and ORF42 and -43 also showed variations useful in grouping subpopulations of this... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00083/19445/17221.pdf |
| |
|
|
| Moreau, Pierrick; Moreau, Kevin; Segarra, Amelie; Tourbiez, Delphine; Travers, Marie-agnes; Rubinsztein, David C.; Renault, Tristan. |
| Recent mass mortality outbreaks around the world in Pacific oysters, Crassostrea gigas, have seriously affected the aquaculture economy. Although the causes for these mortality outbreaks appear complex, infectious agents are involved. Two pathogens are associated with mass mortality outbreaks, the virus ostreid herpesvirus 1 (OsHV-1) and the bacterium Vibrio aestuarianus. Here we describe the interactions between these 2 pathogens and autophagy, a conserved intracellular pathway playing a key role in innate immunity. We show for the first time that autophagy pathway is present and functional in Pacific oysters and plays an important role to protect animals from infections. This study contributes to better understand the innate immune system of Pacific... |
| Tipo: Text |
Palavras-chave: Autophagy; Crassostrea gigas; OsHV-1; Pacific oyster; Vibrio aestuarianus; ATG; Autophagy-related; Atg8-PE; Atg8-phosphatidylethenolamine; DNA; Deoxyribonucleic acid; Hpi; Hours postinfection; LC3-II; Cleaved; Lipidated and autophagosome-associated form of LC3; MAP1LC3A; B (LC3A; B); Microtubule-associated proteins 1 light chain 3 alpha. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00269/37989/36072.pdf |
| |
|
|
| Schikorski, David; Renault, Tristan; Saulnier, Denis; Faury, Nicole; Moreau, Pierrick; Pepin, Jean-francois. |
| In 2008 and 2009, acute mortalities occurred in France among Pacific cupped oyster, Crassostrea gigas, spat. Different hypothesis including the implication of environmental factors, toxic algae and/or pathogens have been explored. Diagnostic tests indicated that OsHV-1 including a particular genotype, termed OsHV-1 mu Var, was detected in most of samples and especially in moribund oysters with the highlighting of virus particles looking like herpes viruses by TEM examination. In this study, an experimental protocol to reproduce OsHV-1 infection in laboratory conditions was developed. This protocol was based on the intramuscular injection of filtered (0.22 mu m) tissue homogenates prepared from naturally OsHV-1 infected spat collected on French coasts... |
| Tipo: Text |
|
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00037/14795/12104.pdf |
| |
|
|
| Moreau, Pierrick; Burgeot, Thierry; Renault, Tristan. |
| Pesticides are frequently detected in estuaries among the pollutants found in estuarine and coastal areas and may have major ecological consequences. They could endanger organism growth, reproduction or survival. In the context of high mortality outbreaks affecting Pacific oysters, Crassostrea gigas, in France since 2008, it appears of importance to determine the putative effects of pesticides on oyster susceptibility to infectious agents. Massive mortality outbreaks reported in this species, mainly in spring and summer, may suggest an important role played by the seasonal use of pesticides and freshwater input in estuarine areas where oyster farms are frequently located. To understand the impact of some pesticides detected in French waters, their effects... |
| Tipo: Text |
Palavras-chave: Immunity; Hemocytes; Pesticides; Pacific oyster; Crassostrea gigas; Flow cytometry; Bivalve. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00144/25555/23700.pdf |
| |
|
|
|
