Consulta: creatorFacets:"Le Roux, Frederique"
Registros recuperados: 36
Data/hora: 01/06/2024 06:30:44

DEDUCTION : A research project for shrimp farming sustainability in New-Caledonia
Provedor de dados: 5
Autores: Beliaeff, Benoit; Chim, Liet; Della Patrona, Luc; Goyard, Emmanuel; Herlin, Jose; Labreuche, Yannick; Walling, Emilie; Ansquer, Dominique; Brun, Pierre; Castex, Mathieu; Coatanea, Denis; Courties, Claude; De Lorgeril, Julien; Dufour, Robert; Frappier, Julie; Goarant, Cyrille; Huber, Matthias; Lemaire, Pierrette; Lemonnier, Hugues; Loubersac, Lionel; Le Roux, Frederique; Lucas, Ronan; Patrois, Jacques; Peignon, Jean-marie; Pham, Dominique; Ramage, Yannick; Soulard, Benoit; Vic, Marlene; Vourey, Elodie; Wabete, Nelly.
New Caledonian shrimp farming feasibility studies started in the mid-seventies. Today ca. 2000 tons of Litopenaeus stylirostris, introduced in 1978, are semi-intensively produced each year. Since fifteen years, production has been impacted by two seasonal vibriosis, the “Summer” syndrome caused by Vibrio nigripulchritudo in relation to pond bottom and water column quality, and the “Winter Syndrome” caused by Vibrio penaeicida in relation to drastic temperature drops . With the ambition of elucidating processes possibly leading to mortality outbreaks in ponds, Ifremer has been conducting a research program since 2003 under the DESANS project (2003-2006) and the present DEDUCTION project, equally funded by the South and North Provinces and by the Government...
Tipo: Text
Palavras-chave: Shrimp farming; Technical and scientific support; Vibriosis; Water quality; Pathology; Ecophysiology; Genetics; Zoosanitary monitoring and procedures; Multifactorial and multidisciplinary approach.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00143/25438/23591.pdf

Mortalités d'huîtres creuses adultes (Crassostrea gigas) et infection à Vibrio aestuarianus - AESTU
Provedor de dados: 5
Autores: Travers, Marie-agnes; Degremont, Lionel; De Lorgeril, Julien; Azema, Patrick; Montagnani, Caroline; Benabdelmouna, Abdellah; Nicolas, Jean-louis; Le Roux, Frederique.
En 2012, le nombre de cas de mortalités d’huîtres creuses adultes rapportés dans le cadre du réseau Repamo, et dans lesquels la bactérie Vibrio aestuarianus a été isolée, a fortement augmenté. Afin d’apporter de premiers éléments de réponse concernant cette augmentation, les objectifs de cette étude étaient de déterminer si l’émergence/la ré-émergence de V. aestuarianus était associée (i) à l’apparition d’un génotype bactérien particulier et/ou (ii) à une sensibilité accrue de certains animaux. L’Ifremer dispose d’une collection de souches bactériennes appartenant majoritairement au genre Vibrio et qui comporte différents isolats de V. aestuarianus, collectés depuis 2001 pendant ou hors épisodes de mortalité. La comparaison de ces isolats en termes de...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; Huître creuse; Crassostrea gigas; Bactérie; Ré-émergenece; Virulence; Génome; Statut immunitaire; Génétique.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00229/34037/32430.pdf

Pathotyping of Vibrio Isolates by Multiplex PCR Reveals a Risk of Virulent Strain Spreading in New Caledonian Shrimp Farms
Provedor de dados: 5
Autores: Labreuche, Yannick; Pallandre, Laurane; Ansquer, Dominique; Herlin, Jose; Wapotro, Billy; Le Roux, Frederique.
Two recurring syndromes threaten the viability of the shrimp industry in New Caledonia, which represents the second largest export business. The "Syndrome 93" is a cold season disease due to Vibrio penaeicida affecting all shrimp farms, while the "Summer Syndrome" is a geographically restricted vibriosis caused by a virulent lineage of Vibrio nigripulchritudo. Microbiological procedures for diagnosis of these diseases are time-consuming and do not have the ability to discriminate the range of virulence potentials of V. nigripulchritudo. In this study, we developed a multiplex PCR method to simultaneously detect these two bacterial species and allow for pathotype discrimination. The detection limits of this assay, that includes an internal amplification...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00063/17398/15169.pdf

Rapport annuel 2017 de l’unité Physiologie Fonctionnelle des Organismes Marins (PFOM)
Provedor de dados: 5
Autores: Boudry, Pierre; Fleury, Elodie; Le Roux, Frederique; Zambonino, Jose-luis.
Tipo: Text
Ano: 2018
URL: http://archimer.ifremer.fr/doc/00451/56298/57880.pdf

Species-specific mechanisms of cytotoxicity toward immune cells determine the successful outcome of Vibrio infections
Provedor de dados: 5
Autores: Rubio, Tristan; Oyanedel, Daniel; Labreuche, Yannick; Toulza, Eve; Luo, Xing; Bruto, Maxime; Chaparro, Cristian; Torres, Marta; De Lorgeril, Julien; Haffner, Philippe; Vidal-dupiol, Jeremie; Lagorce, Arnaud; Petton, Bruno; Mitta, Guillaume; Jacq, Annick; Le Roux, Frederique; Charriere, Guillaume; Destoumieux-garzon, Delphine.
Vibrio species cause infectious diseases in humans and animals, but they can also live as commensals within their host tissues. How Vibrio subverts the host defenses to mount a successful infection remains poorly understood, and this knowledge is critical for predicting and managing disease. Here, we have investigated the cellular and molecular mechanisms underpinning infection and colonization of 2 virulent Vibrio species in an ecologically relevant host model, oyster, to study interactions with marine Vibrio species. All Vibrio strains were recognized by the immune system, but only nonvirulent strains were controlled. We showed that virulent strains were cytotoxic to hemocytes, oyster immune cells. By analyzing host and bacterial transcriptional...
Tipo: Text
Palavras-chave: T6SS; Toxin; Dual RNA-seq; Cytolysis; Pathogenesis.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00507/61837/65900.pdf

Ecologically realistic model of infection for exploring the host damage caused by Vibrio aestuarianus
Provedor de dados: 5
Autores: Parizadeh, Leila; Tourbiez, Delphine; Garcia, Celine; Haffner, Philippe; Degremont, Lionel; Le Roux, Frederique; Travers, Marie-agnes.
Although vibrios are frequently associated with marine organisms mortality outbreaks, knowledge on their ecology and pathogenicity is sparse, thus limiting disease management and prophylactic strategies. Here, we investigated V. aestuarianus infection onset and progression in the wild, taking advantage of a “claire” pond: a semi‐closed system with limited seawater renewal, theoretically more adapted to disease transmission. We showed a positive association of the bacteria with oysters, which can constitute a reservoir for the bacteria in the winter. Moreover, passage through oysters was found to be necessary for experimental disease reproduction as vibrios shedding from diseased oysters has higher infectivity than from in vitro grown. We next developed an...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00446/55761/57423.pdf

Colonization of polystyrene microparticles by Vibrio crassostreae: light and electron microscopic investigation
Provedor de dados: 5
Autores: Foulon, Valentin; Le Roux, Frederique; Lambert, Christophe; Huvet, Arnaud; Soudant, Philippe; Paul-pont, Ika.
Microplastics collected at sea harbour a high diversity of microorganisms including some Vibrio genus members, raising questions about the role of microplastics as a novel ecological niche for potentially pathogenic microorganisms. In the present study we investigated the adhesion dynamics of Vibrio crassostreae on polystyrene microparticles (micro-PS) using electronic and fluorescence microscopy techniques. Micro-PS were incubated with bacteria in different media (Zobell culture medium and artificial seawater) with or without natural marine aggregates. The highest percentage of colonised particles (38-100%) was observed in Zobell culture medium, which may be related to nutrient availability for production of pili and exopolysaccharide adhesion structures....
Tipo: Text
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00351/46210/45908.pdf

A single regulatory gene is sufficient to alter Vibrio aestuarianus pathogenicity in oysters
Provedor de dados: 5
Autores: Goudenege, David; Travers, Marie-agnes; Lemire, Astrid; Petton, Bruno; Haffner, Philippe; Labreuche, Yannick; Tourbiez, Delphine; Mangenot, Sophie; Calteau, Alexandra; Mazel, Didier; Nicolas, Jean-louis; Jacq, Annick; Le Roux, Frederique.
Oyster diseases caused by pathogenic vibrios pose a major challenge to the sustainability of oyster farming. In France since 2012 a disease affecting specifically adult oysters has been associated with the presence of Vibrio aestuarianus. Here, by combining genome comparison, phylogenetic analyses and high throughput infections of strains isolated before or during the recent outbreaks, we show that virulent strains cluster into two V. aestuarianus lineages independently of the sampling dates. The bacterial lethal dose was not different between strains isolated before or after 2012. Hence the emergence of a new highly virulent clonal strain is unlikely. Each lineage comprises nearly identical strains, the majority of them being virulent, suggesting that...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00226/33685/32530.pdf

Ancestral gene acquisition as the key to virulence potential in environmental Vibrio populations
Provedor de dados: 5
Autores: 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
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00452/56370/57967.pdf

Immune-suppression by OsHV-1 viral infection causes fatal bacteraemia in Pacific oysters
Provedor de dados: 5
Autores: De Lorgeril, Julien; Lucasson, Aude; Petton, Bruno; Toulza, Eve; Montagnani, Caroline; Clerissi, Camille; Vidal-dupiol, Jeremie; Chaparro, Cristian; Galinier, Richard; Escoubas, Jean Michel; Haffner, Philippe; Degremont, Lionel; Charriere, Guillaume; Lafont, Maxime; Delort, Abigail; Vergnes, Agnes; Chiarello, Marlene; Faury, Nicole; Rubio, Tristan; Leroy, Marc; Perignon, Adeline; Regler, Denis; Morga, Benjamin; Alunno-bruscia, Marianne; Boudry, Pierre; Le Roux, Frederique; Destoumieux-garzon, Delphine; Gueguen, Yannick; Mitta, Guillaume.
Infectious diseases are mostly explored using reductionist approaches despite repeated evidence showing them to be strongly in fluenced by numerous interacting host and environmental factors. Many diseases with a complex aetiology therefore remain misunderstood. By developing a holistic approach to tackle the complexity of interactions, we decipher the complex intra-host interactions underlying Pacific oyster mortality syndrome affecting juveniles of Crassostrea gigas, the main oyster species exploited worldwide. Using experimental infections reproducing the natural route of infection and combining thorough molecular analyses of oyster families with contrasted susceptibilities, we demonstrate that the disease is caused by multiple infection with an initial...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00461/57234/59228.pdf

Nigritoxin is a bacterial toxin for crustaceans and insects
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00408/51934/52563.pdf

Oysters and Vibrios as a Model for Disease Dynamics in Wild Animals
Provedor de dados: 5
Autores: Le Roux, Frederique; Wegner, K. Mathias; Polz, Martin F.
Disease dynamics in the wild are influenced by a number of ecological and evolutionary factors not addressed by traditional laboratory-based characterization of pathogens. Here we propose the oyster, Crassostrea gigas, as a model for studying the interaction of the environment, bacterial pathogens, and the host in disease dynamics. We show that an important first step is to ask whether the functional unit of pathogenesis is a bacterial clone, a population, or a consortium in order to assess triggers of disease outbreaks and devise appropriate monitoring tools. Moreover, the development of specific-pathogen-free (SPF) oysters has enabled assessment of the infection process under natural conditions. Finally, recent results show the importance of microbial...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00323/43466/46569.pdf

Populations, not clones, are the unit of vibrio pathogenesis in naturally infected oysters
Provedor de dados: 5
Autores: Lemire, Astrid; Goudenege, David; Versigny, Tiphaine; Petton, Bruno; Calteau, Alexandra; Labreuche, Yannick; Le Roux, Frederique.
Disease in oysters has been steadily rising over the past decade, threatening the long-term survival of commercial and natural stocks. Our understanding and management of such diseases are of critical importance as aquaculture is an important aspect of dealing with the approaching worldwide food shortage. Although some bacteria of the Vibrio genus isolated from diseased oysters have been demonstrated to be pathogenic by experimental infection, direct causality has not been established. Little is known about the dynamics of how the bacterial population hosted by oysters changes during disease progression. Combining experimental ecology, a high-throughput infection assay and genome sequencing, we show that the onset of disease in oysters is associated with...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00244/35565/34107.pdf

Genome sequence of Vibrio diabolicus and identification of the exopolysaccharide HE800 biosynthesis locus
Provedor de dados: 5
Autores: Goudenege, David; Boursicot, Vincent; Versigny, Typhaine; Bonnetot, Sandrine; Ratiskol, Jacqueline; Sinquin, Corinne; Lapointe, Gisele; Le Roux, Frederique; Delbarre-ladrat, Christine.
Vibrio diabolicus, a marine bacterium originating from deep-sea hydrothermal vents, produces the HE800 exopolysaccharide with high value for biotechnological purposes, especially for human health. Its genome was sequenced and analyzed; phylogenetic analysis using the core genome revealed V. diabolicus is close to another deep-sea Vibrio sp. (Ex25) within the Harveyi clade and Alginolyticus group. A genetic locus homologous to the syp cluster from Vibrio fischeri was demonstrated to be involved in the HE800 production. However, few genetic particularities suggest that the regulation of syp expression may be different in V. diabolicus. The presence of several types of glycosyltransferases within the locus indicates a capacity to generate diversity in the...
Tipo: Text
Palavras-chave: Genome; Vibrio; Exopolysaccharide; Biosynthesis.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00241/35244/33892.pdf

csrB Gene Duplication Drives the Evolution of Redundant Regulatory Pathways Controlling Expression of the Major Toxic Secreted Metalloproteases in Vibrio tasmaniensis LGP32
Provedor de dados: 5
Autores: Nguyen, An Ngoc; Disconzi, Elena; Charriere, Guillaume; Destoumieux-garzon, Delphine; Bouloc, Philippe; Le Roux, Frederique; Jacq, Annick.
CsrBs are bacterial highly conserved and multiple-copy noncoding small RNAs (sRNAs) that play major roles in cell physiology and virulence. In the Vibrio genus, they are known to be regulated by the two-component system VarSNarA. They modulate the well-characterized quorum sensing pathway controlling virulence and luminescence in Vibrio cholerae and Vibrio harveyi, respectively. Remarkably, Vibrio tasmaniensis LGP32, an oyster pathogen that belongs to the Splendidus Glade, was found to have four copies of csrB, named csrB1-4, compared to two to three copies in other Vibrio species. Here, we show that the extra csrB4 copy results from a csrB3 gene duplication, a characteristic of the Splendidus Glade. Interestingly, csrB genes are regulated in different...
Tipo: Text
Palavras-chave: Bacterial gene regulation; Bacterial sRNAs; Transcriptomics; Vibrio pathogenic to oysters; Host-pathogen interactions.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00476/58785/61319.pdf

Rapport d’activité 2015 - Unité Physiologie Fonctionnelle des Organismes Marins
Provedor de dados: 5
Autores: Boudry, Pierre; Alunno-bruscia, Marianne; Zambonino, Jose-luis; Le Roux, Frederique.
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00346/45767/45409.pdf

The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11-12th March 2015)
Provedor de dados: 5
Autores: Le Roux, Frederique; Wegner, K. Mathias; Baker-austin, Craig; Vezzulli, Luigi; Osorio, Carlos R.; Amaro, Carmen; Ritchie, Jennifer M.; Defoirdt, Tom; Destoumieux-garzon, Delphine; Blokesch, Melanie; Mazel, Didier; Jacq, Annick; Cava, Felipe; Gram, Lone; Wendling, Carolin C.; Strauch, Eckhard; Kirschner, Alexander; Huehn, Stephan.
Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio emergence. A major challenge is to foster cooperation between...
Tipo: Text
Palavras-chave: Global warming; Human health; Aquaculture; Interactions; Animal model; Bacterial disease; Genome plasticity; European network.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00278/38952/37494.pdf

Comparative genomics of pathogenic lineages of Vibrio nigripulchritudo identifies virulence-associated traits
Provedor de dados: 5
Autores: Goudenege, David; Labreuche, Yannick; Krin, Evelyne; Ansquer, Dominique; Mangenot, Sophie; Calteau, Alexandra; Medigue, Claudine; Mazel, Didier; Polz, Martin F.; Le Roux, Frederique.
Vibrio nigripulchritudo is an emerging pathogen of farmed shrimp in New Caledonia and other regions in the Indo-Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have suggested that pathogenicity is linked to particular lineages. Here, we performed high-throughput sequencing-based comparative genome analysis of 16 V. nigripulchritudo strains to explore the genomic diversity and evolutionary history of pathogen-containing lineages and to identify pathogen-specific genetic elements. Our phylogenetic analysis revealed three pathogen-containing V. nigripulchritudo clades, including two clades previously identified from New Caledonia and one novel clade comprising putatively...
Tipo: Text
Palavras-chave: Horizontal gene transfer; Nigritoxin; Phylogeny; Shrimp; Virulence; Vibrio.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00160/27117/28369.pdf

Diagnosis of vibriosis in the era of genomics: lessons from invertebrates
Provedor de dados: 5
Autores: Le Roux, Frederique.
Global changes linked to increases in temperature and ocean acidification, but also to more direct anthropogenic influences such as aquaculture, have caused a worldwide increase in the reports of Vibrio-associated illnesses affecting humans and also animals such as shrimp and molluscs. Investigation of the emergence of Vibrio pathogenesis events requires the analysis of microbial evolution at the gene, genome and population levels, in order to identify genomic modifications linked to increased virulence, resistance and/or prevalence, or to recent host shift. From a more applied point of view, the elucidation of virulence mechanisms is a prerequisite to devising prophylactic methods to fight infectious agents. In comparison with human pathogens, fairly...
Tipo: Text
Palavras-chave: Écologie; Émergence; Évolution; Invertébrés marins; Vibriose; Virulence; Ecology; Emergence; Evolution; Marine invertebrate; Vibriosis; Virulence.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00344/45560/46722.pdf

Vibrio crassostreae, a benign oyster colonizer turned into a pathogen after plasmid acquisition
Provedor de dados: 5
Autores: 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
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00360/47137/49044.pdf

The major outer membrane protein OmpU of Vibrio splendidus contributes to host antimicrobial peptide resistance and is required for virulence in the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Duperthuy, Marylise; Binesse, Johan; Le Roux, Frederique; Romestand, Bernard; Caro, Audrey; Got, Patrice; Givaudan, Alain; Mazel, Didier; Bachere, Evelyne; Destoumieux Garzon, Delphine.
Vibrio splendidus, strain LGP32, is an oyster pathogen associated with the summer mortalities affecting the production of Crassostrea gigas oysters worldwide. Vibrio splendidus LGP32 was shown to resist to up to 10 mu M Cg-Def defensin and Cg-BPI bactericidal permeability increasing protein, two antimicrobial peptides/proteins (AMPs) involved in C. gigas immunity. The resistance to both oyster Cg-Def and Cg-BPI and standard AMPs (polymyxin B, protegrin, human BPI) was dependent on the ompU gene. Indeed, upon ompU inactivation, minimal bactericidal concentrations decreased by up to fourfold. AMP resistance was restored upon ectopic expression of ompU. The susceptibility of bacterial membranes to AMP-induced damages was independent of the ompU-mediated AMP...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00003/11421/8044.pdf

Bilan 1999 du Réseau REPAMO - Réseau National de Surveillance zoosanitaire des Mollusques marins
Provedor de dados: 5
Autores: Thebault, Anne; Martin, Anne-genevieve; Le Coguic, Yvette; Hirata, Toshio; Tige, Gilbert; Pichot, Yves; Grizel, Henri; Berthe, Franck; Cochennec, Nathalie; Renault, Tristan; Le Roux, Frederique.
Le réseau REPAMO (Réseau de Pathologie des Mollusques) est un réseau de santé animale, qui s'occupe des coquillages marins du littoral français métropolitain. Les mollusques marins des côtes françaises représentent une ressource par la pêche, mais sont surtout une part importante de l'aquaculture. Les pertes liées aux maladies dans ce domaine d'activité sont aujourd'hui considérées comme l'un des principaux facteurs limitants de son développement au niveau mondial. Deux exemples récents suffisent à illustrer ce danger pour l'ostréiculture française : • La culture de l''huître plate Ostrea edulis, déjà atteinte par un parasite, Marteilia refringens, est passée en quelques années de 20 000 tonnes à 1800 tonnes, suite à une épizootie. En effet à la fin des...
Tipo: Text
Palavras-chave: Réseau surveillance; Pathologie; Mollusques bivalves; Mortalité.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00098/20903/18522.pdf

Vibrio splendidus   O-antigen structure: A trade-off between virulence to oysters and resistance to grazers
Provedor de dados: 5
Autores: Oyanedel, Daniel; Labreuche, Yannick; Bruto, Maxime; Amraoui, Hajar; Robino, Etienne; Haffner, Philippe; Rubio, Tristan; Charrière, Guillaume; Le Roux, Frederique; Destoumieux-garzón, Delphine.
A major debate in evolutionary biology is whether virulence is maintained as an adaptive trait and/or evolves to non‐virulence. In the environment, virulence traits of non‐obligatory parasites are subjected to diverse selective pressures and trade‐offs. Here we focus on a population of Vibrio splendidus that displays moderate virulence for oysters. A MARTX (Multifunctional‐autoprocessing repeats‐in‐toxin) and a type‐six secretion system (T6SS) were found to be necessary for virulence toward oysters, while a region (wbe) involved in O‐antigen synthesis is necessary for resistance to predation against amoebae. Gene inactivation within the wbe region had major consequences on the O‐antigen structure, conferring lower immunogenicity, competitive advantage and...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00619/73070/72194.pdf

Vibrio aestuarianus zinc metalloprotease causes lethality in the Pacific oyster Crassostrea gigas and impairs the host cellular immune defenses
Provedor de dados: 5
Autores: 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

Selection of  Vibrio crassostreae  relies on a plasmid expressing a type 6 secretion system cytotoxic for host immune cells
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00510/62129/66343.pdf

Molecular Targets for Coevolutionary Interactions Between Pacific Oyster Larvae and Their Sympatric Vibrios
Provedor de dados: 5
Autores: Wegner, K. Mathias; Piel, Damien; Bruto, Maxime; John, Uwe; Mao, Zhijuan; Alunno-bruscia, Marianne; Petton, Bruno; Le Roux, Frederique.
Bacteria of the Vibrio genus are the most predominant infectious agents threatening marine wildlife and aquaculture. Due to the large genetic diversity of these pathogens, the molecular determinants of Vibrio virulence are only poorly understood. Furthermore, studies tend to ignore co-evolutionary interactions between different host populations and their locally encountered Vibrio communities. Here, we explore the molecular targets of such co-evolutionary interactions by analyzing the genomes of nine Vibrio strains from the Splendidus-clade showing opposite virulence patterns towards two populations of Pacific oysters introduced into European Wadden Sea. By contrasting Vibrio phylogeny to their host specific virulence patterns, we could identify two core...
Tipo: Text
Palavras-chave: Virulence; Host-pathogen interaction; Local adaptation; Biological invasion; Emerging disease; Wadden Sea.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00512/62409/66669.pdf

Use of OmpU porins for attachment and invasion of Crassostrea gigas immune cells by the oyster pathogen Vibrio splendidus
Provedor de dados: 5
Autores: Duperthuy, Marylise; Schmitt, Paulina; Garzon, Edwin; Caro, Audrey; Rosa, Rafael D.; Le Roux, Frederique; Lautredou-audouy, Nicole; Got, Patrice; Romestand, Bernard; De Lorgeril, Julien; Kieffer-jaquinod, Sylvie; Bachere, Evelyne; Destoumieux-garzon, Delphine.
OmpU porins are increasingly recognized as key determinants of pathogenic host Vibrio interactions. Although mechanisms remain incompletely understood, various species, including the human pathogen Vibrio cholera, require OmpU for host colonization and virulence. We have shown previously that OmpU is essential for virulence in the oyster pathogen Vibrio splendidus LGP32. Here, we showed that V. splendidus LGP32 invades the oyster immune cells, the hemocytes, through subversion of host-cell actin cytoskeleton. In this process, OmpU serves as an adhesin/invasin required for beta-integrin recognition and host cell invasion. Furthermore, the major protein of oyster plasma, the extracellular superoxide dismutase Cg-EcSOD, is used as an opsonin mediating the...
Tipo: Text
Palavras-chave: Host-pathogen interaction; Innate immunity; Invertebrate; Mollusk; Oxidative burst.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00031/14177/12166.pdf

Outer membrane vesicles are vehicles for the delivery of Vibrio tasmaniensis virulence factors to oyster immune cells
Provedor de dados: 5
Autores: Vanhove, Audrey; Duperthuy, Marylise; Charriere, Guillaume; Le Roux, Frederique; Goudenege, David; Gourbal, Benjamin; Kieffer-jaquinod, Sylvie; Coute, Yohann; Wai, Sun Nyunt; Destoumieux-garzon, Delphine.
Vibrio tasmaniensis LGP32, a facultative intracellular pathogen of oyster haemocytes, was shown here to release outer membrane vesicles (OMVs) both in the extracellular milieu and inside haemocytes. Intracellular release of OMVs occurred inside phagosomes of intact haemocytes having phagocytosed few vibrios as well as in damaged haemocytes containing large vacuoles heavily loaded with LGP32. The OMV proteome of LGP32 was shown to be rich in hydrolases (25%) including potential virulence factors such as proteases, lipases, phospholipases, haemolysins and nucleases. One major caseinase/gelatinase named Vsp for vesicular serine protease was found to be specifically secreted through OMVs in which it is enclosed. Vsp was shown to participate in the virulence...
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00199/31009/29459.pdf

Genome sequence of Vibrio splendidus: an abundant planctonic marine species with a large genotypic diversity
Provedor de dados: 5
Autores: Le Roux, Frederique; Zouine, Mohamed; Chakroun, Nesrine; Binesse, Johan; Saulnier, Denis; Bouchier, Christiane; Zidane, Nora; Ma, Laurence; Rusniok, Christophe; Lajus, Aurelie; Buchrieser, Carmen; Medigue, Claudine; Polz, Martin F.; Mazel, Didier.
P&gt;Vibrio splendidus is a dominant Vibrio species in seawater presenting a remarkable genetic diversity; several strains have been linked to invertebrate's mortality. We report the complete genome sequence of V. splendidus LGP32, an oyster pathogen, and its comparison with partial genome sequences from related strains. As is typical for the genus, V. splendidus LGP32 contains two chromosomes (3.29 and 1.67 Mb) and most essential cellular processes are encoded by chromosome 1. Comparison with two other V. splendidus partial genome sequences (strains 12B01 and Med222) confirms the previously suggested high genotypic diversity within this species and led to the identification of numerous strain-specific regions that could frequently not be assigned to a...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6632.pdf

The One Health Concept: 10 Years Old and a Long Road Ahead
Provedor de dados: 5
Autores: Destoumieux-garzon, Delphine; Mavingui, Patrick; Boetsch, Gilles; Boissier, Jerome; Darriet, Frederic; Duboz, Priscilla; Fritsch, Clementine; Giraudoux, Patrick; Le Roux, Frederique; Morand, Serge; Paillard, Christine; Pontier, Dominique; Sueur, Cedric; Voituron, Yann.
Over the past decade, a significant increase in the circulation of infectious agents was observed. With the spread and emergence of epizootics, zoonoses, and epidemics, the risks of pandemics became more and more critical. Human and animal health has also been threatened by antimicrobial resistance, environmental pollution, and the development of multifactorial and chronic diseases. This highlighted the increasing globalization of health risks and the importance of the human–animal–ecosystem interface in the evolution and emergence of pathogens. A better knowledge of causes and consequences of certain human activities, lifestyles, and behaviors in ecosystems is crucial for a rigorous interpretation of disease dynamics and to drive public policies. As a...
Tipo: Text
Palavras-chave: One health; EcoHealth; Infectious disease; Non-communicable disease; Multifactorial disease; Ecotoxicology; Interdisciplinary research; Public health.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00425/53676/54518.pdf

Virulence of an emerging pathogenic lineage of Vibrio nigripulchritudo is dependent on two plasmids
Provedor de dados: 5
Autores: Le Roux, Frederique; Labreuche, Yannick; Davis, Brigid M.; Iqbal, Naeem; Mangenot, Sophie; Goarant, Cyrille; Mazel, Didier; Waldor, Matthew K.
Vibrioses are the predominant bacterial infections in marine shrimp farms. Vibrio nigripulchritudo is an emerging pathogen of the cultured shrimp Litopenaeus stylirostris in New Caledonia and other regions in the Indo-Pacific. The molecular determinants of V. nigripulchritudo pathogenicity are unknown; however, molecular epidemiological studies have revealed that recent pathogenic V. nigripulchritudo isolates from New Caledonia all cluster into a monophyletic clade and contain a small plasmid, pB1067. Here, we report that a large plasmid, pA1066 (247 kb), can also serve as a marker for virulent V. nigripulchritudo, and that an ancestral version of this plasmid was likely acquired prior to other virulence-linked markers. Additionally, we demonstrate that...
Tipo: Text
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00031/14196/11469.pdf

Rapport d’activité 2018-2019 UNITE RBE/PFOM. Physiologie Fonctionnelle des Organismes Marins
Provedor de dados: 5
Autores: Boudry, Pierre; Fleury, Elodie; Le Roux, Frederique; Zambonino Infante, Jose-luis.
Activités scientifiques 2018-2019
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00689/80155/83222.pdf

Etude des agents pathogènes et épidémiologie
Provedor de dados: 5
Autores: Renault, Tristan; Le Roux, Frederique; Berthe, Franck; Robert, Maeva; Chollet, Bruno; Gerard, Andre.
Le programme 4 portant sur la pathologie des coquillages dans le cadre d'une gestion durable des productions ostréicoles, comporte 2 actions principales réparties en une étude d'épidémiologie analytique et descriptive des agents pathogènes (Action 1), et l'étude des relations hôtes/agents pathogènes (Action 2). Les résultats 2001 présentés ici sont relatifs à ces 2 actions, avec notamment des informations sur les infections à virus de type herpès, et de recherche de bactéries pathogènes chez Crassostrea gigas lors des épisodes de mortalités estivales. Par ailleurs, l'émergence d'un programme national, intitulé MOREST (pour Mortalités Estivales) sur l' huître creuse C. gigas va permettre de rappeler le contexte scientifique des relations hôtes/pathogènes.
Tipo: Text
Palavras-chave: Pathologie; Agents pathogènes; Epidémiologie; Huître creuse; Crassostrea gigas.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00199/31011/29414.pdf

Crassostrea gigas mortality in France: the usual suspect, a herpes virus, may not be the killer in this polymicrobial opportunistic disease
Provedor de dados: 5
Autores: Petton, Bruno; Bruto, Maxime; James, Adele; Labreuche, Yannick; Alunno-bruscia, Marianne; Le Roux, Frederique.
Successive disease outbreaks in oyster (Crassostrea gigas) beds in France have resulted in dramatic losses in production, and subsequent decline in the oyster-farming industry. Deaths of juvenile oysters have been associated with the presence of a herpes virus (OsHV-1 µvar) and bacterial populations of the genus Vibrio. Although the pathogenicity of OsHV-1 µvar, as well as several strains of Vibrio has been demonstrated by experimental infections, our understanding of the complexity of infections occurring in the natural environment remains limited. In the present study, we use specific-pathogen-free (SPF) oysters infected in an estuarine environment to study the diversity and dynamics of cultured microbial populations during disease expression. We observe...
Tipo: Text
Palavras-chave: Pacific oysters; Summer mortality; Herpes virus; Vibrio pathogenicity; Experimental infection.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00271/38220/36377.pdf

Vibrio gigantis sp nov., isolated from the haemolymph of cultured oysters (Crassostrea gigas)
Provedor de dados: 5
Autores: Le Roux, Frederique; Goubet, A; Thompson, F; Faury, Nicole; Gay, Melanie; Swings, J; Saulnier, Denis.
Polyphasic analysis of four new Vibrio isolates originating from the haemolymph of diseased cultured oysters is described. The new isolates were closely related to Vibrio splendidus, having 98 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on DNA gyrase subunit B (gyrB), RNA polymerase Quo factor (rpoD), replication origin-binding protein (rctB) and transmembrane regulatory protein (toxR) genes, fluorescent amplified fragment length polymorphism and DNA-DNA hybridization experiments clearly showed that the new isolates form a tight genomic group that is different from the currently known Vibrio species. It is proposed that these new isolates should be accommodated in a novel species, Vibrio gigantis sp. nov. Phenotypic features that...
Tipo: Text
Palavras-chave: Vibrio gigantis; Haemoplymph; Disease; Crassostrea gigas; Oyster culture.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-792.pdf

Epidémiologie analytique et descriptive des agents pathogènes, étude de la diversité des virus de type herpès (action 1). Etude des relations hôtes/agents pathogènes, pathogénèse des infections à virus de type herpèsvirus (action 2) - Contrat Région Poitou-Charentes 2000-2006
Provedor de dados: 5
Autores: Renault, Tristan; Le Roux, Frederique; Berthe, Franck; Arzul, Isabelle; Miossec, Laurence; Robert, Maeva; Chollet, Bruno.
Nous disposons aujourd'hui d'o utils diagnostiques sensibles et spécifiques (PCR, HIS ... ) et d'un protocole de transmission de l' infection qui permettent d'assurer un suivi des productions larvaires en écloserie de bivalves pour les espèces considérées comme sensibles aux infections à herpèsvirus, mais également pour de nouvelles espèces. En effet, des mortalités massives (100 %) ont été rapportées dans une écloserie de coquille St-Jacques en Bretagne et ont pu être associées à la détection de OsHV -1. Les résultats obtenus concernant cette espèce, Pecten maximus, complètent et reflètent l'ensemble des travaux réalisés.
Tipo: Text
Palavras-chave: Pathologie; Epidémiologie; Virus; Herpès virus; Bivalves; Crassostrea gigas; Ruditapes philippinarum; Pecten maximus.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00043/15472/12851.pdf