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| Bruto, Maxime; James, Adele; Petton, Bruno; Labreuche, Yannick; Chenivesse, Sabine; Alunno-bruscia, Marianne; Polz, Martin F.; Le Roux, Frederique. |
| Vibrios are frequently associated with oyster mortality; however whether they are the primary causative agent or secondary opportunistic colonizers is not well understood. Here we combine analysis of natural infection dynamics, population genomics and molecular genetics to ask (i) to what extent oysters are passively colonized by Vibrio population present in the surrounding water, (ii) how populations turn over during pathogenicity events and (iii) what genetic factors are responsible for pathogenicity. We identified several populations of Vibrio preferentially associated with oyster tissues. Among these, Vibrio crassostreae is particularly abundant in diseased animals while nearly absent in the surrounding water, and its pathogenicity is correlated with... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00360/47137/49044.pdf |
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| Piel, Damien; Bruto, Maxime; James, Adele; Labreuche, Yannick; Lambert, Christophe; Janicot, Adrian; Chenivesse, Sabine; Petton, Bruno; Wegner, K. Mathias; Stoudmann, Candice; Blokesch, Melanie; Le Roux, Frederique. |
| Pacific oyster mortality syndrome affects juveniles of Crassostrea gigas oysters and threatens the sustainability of commercial and natural stocks of this species. Vibrio crassostreae has been repeatedly isolated from diseased animals and the majority of the strains have been demonstrated to be virulent for oysters. In this study we showed that oyster farms exhibited a high prevalence of a virulence plasmid carried by V. crassostreae while oysters, at an adult stage, were reservoirs of this virulent population. The pathogenicity of V. crassostreae depends on a novel transcriptional regulator, which activates the bidirectional promoter of a Type 6 Secretion System (T6SS) genes cluster. Both the T6SS and a second chromosomal virulence factor, r5.7, are... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00510/62129/66343.pdf |
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| Bruto, Maxime; Labreuche, Yannick; James, Adele; Piel, Damien; Chenivesse, Sabine; Petton, Bruno; Polz, Martin F.; Le Roux, Frederique. |
| Diseases of marine animals caused by bacteria of the genus Vibrio are on the rise worldwide. Understanding the eco-evolutionary dynamics of these infectious agents is important for predicting and managing these diseases. Yet, compared to Vibrio infecting humans, knowledge of their role as animal pathogens is scarce. Here we ask how widespread is virulence among ecologically differentiated Vibrio populations, and what is the nature and frequency of virulence genes within these populations? We use a combination of population genomics and molecular genetics to assay hundreds of Vibrio strains for their virulence in the oyster Crassostrea gigas, a unique animal model that allows high-throughput infection assays. We show that within the diverse Splendidus... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00452/56370/57967.pdf |
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| Labreuche, Yannick; Chenivesse, Sabine; Jeudy, Alexandra; Le Panse, Sophie; Boulo, Viviane; Ansquer, Dominique; Pages, Sylvie; Givaudan, Alain; Czjzek, Mirjam; Le Roux, Frederique. |
| The Tetraconata (Pancrustacea) concept proposes that insects are more closely related to aquatic crustaceans than to terrestrial centipedes or millipedes. The question therefore arises whether insects have kept crustacean-specific genetic traits that could be targeted by specific toxins. Here we show that a toxin (nigritoxin), originally identified in a bacterial pathogen of shrimp, is lethal for organisms within the Tetraconata and non-toxic to other animals. X-ray crystallography reveals that nigritoxin possesses a new protein fold of the α/β type. The nigritoxin N-terminal domain is essential for cellular translocation and likely encodes specificity for Tetraconata. Once internalized by eukaryotic cells, nigritoxin induces apoptotic cell death through... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00408/51934/52563.pdf |
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