Consulta: creatorFacets:"Labreuche, Yannick"
Registros recuperados: 33
Data/hora: 06/06/2024 09:57:28

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

Effects of extracellular products from the pathogenic Vibrio aestuarianus strain 01/32 on lethality and cellular immune responses of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Labreuche, Yannick; Soudant, Philippe; Goncalves, Madeleine; Lambert, Christophe; Nicolas, Jean-louis.
Vibrio aestuarianus strain 01/32 was previously shown to be pathogenic to Crassostrea gigas juveniles. To investigate virulence mechanisms of this pathogen, we studied the toxicity to oysters of its extracellular products (ECPs). ECPs displayed lethality to animals, with a LD50 value of 3.3 mu g/g body weight. To determine the oyster cellular immune responses induced by these ECPs, we further examined in vitro their effects on C. gigas hemocytes, using flow cytometric-based hemocyte assays. Treatment of hemolymph with ECPs caused a significant inhibition of hemocyte phagocytosis and adhesive capabilities. In contrast, the pathway of reactive oxygen species production was enhanced by higher ECP concentrations. Exposure of hemocytes to live bacteria induced...
Tipo: Text
Palavras-chave: Vibrio aestuarianus; ECPs; Crassostrea gigas; ROS production; Adhesion; Phagocytosis; Flow cytometry; Bivalve immunity.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-1035.pdf

The identification of genes from the oyster Crassostrea gigas that are differentially expressed between progeny exhibiting opposed susceptibility to summer mortality
Provedor de dados: 5
Autores: Huvet, Arnaud; Degremont, Lionel; Labreuche, Yannick; Daniel, Jean-yves; Dubrunfaut, Thomas; Boudry, Pierre; Haure, Joel; Bedier, Edouard; Ropert, Michel; Herpin, Amaury; Cunningham, Charles; Moal, Jeanne; Samain, Jean-francois.
Summer mortality associated with juveniles of the oyster Crassostrea gigas is the result of a complex interaction between the host, pathogens and environment. Divergent selection based on summer survival have been applied to produce families with resistant and susceptible progeny. Here, we describe the use of suppression subtractive hybridization to generate 150 clones that were differentially regulated between resistant and susceptible F2 progeny. The nucleotide sequence of these 150 clones was determined. Among the 25 unique sequences that matched with the products of known genes, those putatively implicated in energy generation (12%) and immune function (16%), systems suspected to be implicated in summer mortality, were extended and analyzed by real...
Tipo: Text
Palavras-chave: Selection; Gene; Genetic; Summer mortality; Crassostrea gigas; Pacific oysters.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/acte-3447.pdf

Non-specific activation of antiviral immunity and induction of RNA interference may engage the same pathway in the Pacific white leg shrimp Litopenaeus vannamei
Provedor de dados: 5
Autores: Labreuche, Yannick; Veloso, Artur; De La Vega, Enrique; Gross, Paul S.; Chapman, Robert W.; Browdy, Craig L.; Warr, Gregory W.
Many questions remain unanswered regarding RNAi-based mechanisms and dsRNA-induced antiviral immune responses in penaeid shrimp. In this study, we report the characterization in the white leg shrimp Litopenaeus vannamei of RNAi pathway associated proteins Lv-Ago 1 and Lv-Ago 2, two members of the Argonaute family of proteins, as well as Lv-sid 1, the first shrimp homologue of Sid-1, a membrane channel-forming protein implicated in the cellular import of dsRNA. To decipher their functional implication in RNAi-related phenomena, we monitored their relative expression following stimulation by specific and non-specific RNA duplexes of diverse length. The findings show that the length of small RNA duplexes plays a critical role in the activation of both...
Tipo: Text
Palavras-chave: Shrimp; Litopenaeus vannamei; RNAi; DsRNA; Argonaute; Sid-1; Antiviral immunity.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00015/12652/9587.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

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

Selection and characterization of potential probiotic bacteria for Litopenaeus stylirostris shrimp hatcheries in New Caledonia
Provedor de dados: 5
Autores: Pham, Dominique; Ansquer, Dominique; Chevalier, Anne; Dauga, Clement; Peyramale, Aude; Wabete, Nelly; Labreuche, Yannick.
In New Caledonia, shrimp hatcheries are confronted with mass mortality in the larval stages, a phenomenon poorly understood as no specific causative agent has been identified. This has resulted in an excessive use of prophylactic antibiotics, although their adverse effects in aquaculture are notorious. The present work was thus aimed at selecting potential probiotic strains for penaeid hatcheries.  From a pool of more than 400 marine bacterial isolates sampled from the local marine environment seven strains exhibited in vitro antagonistic activity towards Vibrio harveyi. These isolates were characterized both phenotypically and genotypically using a biochemical approach and 16S rDNA sequencing. Six out of these seven strains were found to belong to the...
Tipo: Text
Palavras-chave: Shrimp; Litopenaeus stylirostris; Probiotic; Hatchery; Pseudoalteromonas; Immune response.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00190/30129/28591.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

Advances in Genomics and Genetics of Penaeid Shrimp
Provedor de dados: 5
Autores: Robalino, Javier; Chapman, Robert W.; De La Vega, Enrique; O'Leary, Nuala A.; Gorbach, Danielle M.; Du, Zhi-qiang; Rothschild, Max F.; Browdy, Craig L.; Warr, Gregory; Labreuche, Yannick.
This chapter contains sections titled:    Introduction    EST Collection as an Approach to Gene Discovery in Shrimp    Medium- to High-Throughput Studies of Differential Expression and Gene Discovery    RNAi-Based Applications in Shrimp Aquaculture: From Reverse Genetics to Control of Diseases    Markers, Genetic Maps, and Large Insert Genomic Libraries in Shrimp    Analytical Challenges in Genomics and Genetics of Shrimp    Concluding Remarks    Acknowledgments    References
Tipo: Text
Palavras-chave: Penaeid shrimp EST collection; Gene discovery gene expression “snapshot” gametogenesis abiotic stress responses differential expression cloning RNAi-based applications; Shrimp targeted gene silencing RNAi; And gene function genetic markers in breeding.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00070/18149/15775.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

The Role of the Glyoxylate Shunt in the Acclimation to Iron Limitation in Marine Heterotrophic Bacteria
Provedor de dados: 5
Autores: Koedooder, Coco; Gueneugues, Audrey; Van Geersdaele, Remy; Verge, Valerie; Bouget, Francois-yves; Labreuche, Yannick; Obernosterer, Ingrid; Blain, Stephane.
Iron (Fe) is an essential element for marine microbial growth but is present in trace amounts (&lt;0.1 nM) in surface waters of the ocean. In heterotrophic bacteria, Fe-limitation particularly impacts ATP production as Fe is an essential co-factor of enzymes involved in the electron-transport chain as well as the tricarboxylic acid (TCA) cycle. Fe-limitation can therefore drastically reduce both bacterial growth and respiration, consequently affecting the efficiency of organic carbon remineralization. Heterotrophic bacteria possess various strategies to cope with Fe-limitation. In the present study we tested the hypothesis that the induction of the glyoxylate shunt can represent one such strategy. Genetic approaches were used to gain insight into the...
Tipo: Text
Palavras-chave: Iron; Fe-limitation; Photobacterium angustum S14; Glyoxylate shunt; Isocitrate lyase.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00468/58017/60413.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

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

In vitro modulation of reactive oxygen and nitrogen intermediate (ROI/RNI) production in Crassostrea gigas hemocytes
Provedor de dados: 5
Autores: Lambert, Christophe; Soudant, Philippe; Jegaden, Marine; Delaporte, Maryse; Labreuche, Yannick; Moal, Jeanne; Samain, Jean-francois.
Bivalve hemocyte competence has been measured by quantifying functional characteristics, including reactive oxygen intermediate (ROI) production after activation with zymosan or phorbol myristate acetate (PMA). However, untreated oyster hemocytes also produce ROI and RNI (reactive nitrogen intermediates) after bleeding even if not stimulated by Zymosan or PMA. Extensive investigation of this parameter by flow cytometry showed that, in vitro, ROI/RNI production by untreated hemocytes maintained in seawater appeared to be independent of both bacterial burden in the serum and non-self particle phagocytosis. ROI/ RNI production in granulocytes was higher than in hyalinocytes and could be intensified when activated by zymosan but not by PMA. Both cell types...
Tipo: Text
Palavras-chave: NO synthase; NADPH oxidase; Flow cytometry; Reactive nitrogen intermediate RNI; Reactive oxygen intermediate ROI; Hemocytes; Crassostrea gigas.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3057.pdf

Ontogeny of osmoregulation in the Pacific blue shrimp, Litopenaeus stylirostris (decapoda, penaeidae): Deciphering the role of the Na+/K+-ATPase
Provedor de dados: 5
Autores: Pham, Dominique; Charmantier, Guy; Boulo, Viviane; Wabete, Nelly; Ansquer, Dominique; Dauga, Clement; Grousset, Evelyse; Labreuche, Yannick; Charmantier-daures, Mireille.
The role of the main ion transporting enzyme Na +/K + − ATPase in osmoregulation processes was investigated in Litopenaeus stylirostris. The development and localization of the osmoregulation sites were studied during ontogenesis by immunodetection of Na+ K+-ATPase using monoclonal antibodies and transmission electron microscopy (TEM). Osmoregulation sites were identified as the pleurae and branchiostegites in the zoeae and mysis stages. In the subsequent post-metamorphic stages the osmoregulatory function was mainly located in the epipodites and branchiostegites and osmotic regulation was later detected in the gills. The presence of ionocytes and microvilli in these tissues confirmed their role in ionic processes. The complete open reading frame of the...
Tipo: Text
Palavras-chave: Penaeid; Litopenaeus stylirostris; Ontogeny; Osmoregulation; Na+/K+-ATPase; RNA interference.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00311/42176/41477.pdf

Proteinaceous exotoxins of shrimp-pathogenic isolates of Vibrio penaeicida and Vibrio nigripulchritudo
Provedor de dados: 5
Autores: Aguirre-guzman, Gabriel; Labreuche, Yannick; Ansquer, Dominique; Espiau, Benoit; Levy, Peva; Ascencio, Felipe; Saulnier, Denis.
The pathogenicity of two V. penaeicida strains, AM101 and KH-1, with different geographic origin, and V. nigripulchritudo strain AM102, were investigated in juvenile blue shrimp species Litopenaeus stylirostris. Alive bacteria and protein fractions (PFs) obtained from cell-free supernatants (CFS) were used in experimental challenges. Strains AM102, AM101, and KH-1 produced respectively 60, 54 and 12% mortality at 96h after infection using 104 cfu mL-1 of bacterial suspension. Exocellular toxin-like factors were evidenced in CFS from the New Caledonian strains (AM102 and AM101) but not the Japanese strain (KH-1). At 48h post injection of each CFS, mortality rates were respectively 96,98 and 5% when these strains were cultivated at 20°C, whereas only O,16...
Tipo: Text
Palavras-chave: Pathogenicity; Exotoxin; Shrimp; Litopenaeus stylirostris; Vibrio nigripulchritudo; Vibrio penaeicida.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/2003/publication-2807.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

Insights into the antiviral functions of the RNAi machinery in penaeid shrimp
Provedor de dados: 5
Autores: Labreuche, Yannick; Warr, Gregory W.
Over the last decade, RNA interference pathways have emerged in eukaryotes as critical regulators of many diverse biological functions including, among others, transcriptional gene regulation, post-transcriptional gene silencing, heterochromatin remodelling, suppression of transposon activity, and antiviral defences. Although this gene silencing process has been reported to be relatively well conserved in species of different phyla, there are important discrepancies between plants, invertebrates and mammals. In penaeid shrimp, the existence of an intact and functional RNAi machinery is supported by a rapidly growing body of evidence. However, the extent to which this process participates to the host immune responses remains poorly defined in this non-model...
Tipo: Text
Palavras-chave: Shrimp; Innate immune response; In vertebrate immunity; RNA interference; Virus.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00119/23063/20899.pdf

Caractérisation de la virulence d'une souche de Vibrio aestuarianus, pathogène de l'huître Crassostrea gigas
Provedor de dados: 5
Autores: Labreuche, Yannick.
In France. shellfish production is a traditional. well-established industry. mainly based upon commercial farming of the Pacifie oyster. Crassostrea gigas. Since the 1980's, annual mass mortalities of C. gigas have been reported during summer. Several studies on this subject have demonstrated that these mortality outbreaks resulted from complex interactions between the physiologieal andJor genetic status of the oysters. environmental factors, and one or more infectious agents, among which are bacteria of the genus Vibrio.
Tipo: Text
Palavras-chave: Huître; Crassostrea gigas; Bactéries; Vibrio aestuarlanus; Pathogénicité; Produits extracellulaires; Métalloprotéase; Hémocytes; Interactions hôte/pathogène; Oyster; Crassostrea gigas; Bacteria; Vibrio aestuarianus; Pathogenicity; Extracellular products; Metalloprotease; Hemocytes; Host/pathogen interactions.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/00034/14561/11859.pdf

Detection of shrimp pathogen Vibrio nigripulchritudo in sediments of a New-Caledonian grow-out pond during a drying period
Provedor de dados: 5
Autores: Charme, Marion; Ansquer, Dominique; Vourey, Elodie; Walling, Emilie; Beliaeff, Benoit; Labreuche, Yannick.
Experimental infections together with epidemiological studies have shown that pathogenic and non‐pathogenic isolates of V. nigripulchritudo co‐existed in shrimp farm environment (2, 3). Moreover, obtained results also demonstrated that the “summer syndrome”was caused by a single, possibly emerging, cluster of virulent strains. Consequently, it was hypothesized that pathogenic strains of V. nigripulchritudo may persist from one year to the next in the shrimp farm environment and re‐develop inside the grow‐out system at the following rearing cycle (3). This study was therefore aimed at determining whether V. nigripulchritudo isolates may survive, or not, in a shrimp pond bottom soil during a 18‐week drying period. To this end, V.nigripulchritudo mapping was...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/00197/30874/29242.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

Lack of evidence for Litopenaeus vannamei Toll receptor (lToll) involvement in activation of sequence-independent antiviral immunity in shrimp
Provedor de dados: 5
Autores: Labreuche, Yannick; O'Leary, Nuala A.; De La Vega, Enrique; Veloso, Artur; Gross, Paul S.; Chapman, Robert W.; Browdy, Craig L.; Warr, Gregory W.
injection of non-specific dsRNA initiates a broad-spectrum innate antiviral immune response in the Pacific white shrimp, Litopenaeus vannamei, however, the receptor involved in recognition of this by-product of viral infections remains unknown. In vertebrates, dsRNA sensing is mediated by a class of Toll-like receptors (TLRs) and results in activation of the interferon system. Because a TLR (lToll) was recently characterized in L. vannamei, we investigated its potential role in dsRNA recognition. We showed that injection of non-specific RNA duplexes did not modify lToll gene expression. A reverse genetic approach was therefore implemented to study its role in vivo. Silencing of lToll did not impair the ability of nonspecific dsRNA to trigger protection...
Tipo: Text
Palavras-chave: Shrimp; Virus; RNA interference; Invertebrate immunity; Innate immune response; Toll like receptor; DSRNA.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6428.pdf

Molecular and phenotypic characterization of Vibrio aestuarianus subsp francensis subsp nov., a pathogen of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: 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

The identification of genes from the oyster Crassostrea gigas that are differentially expressed in progeny exhibiting opposed susceptibility to summer mortality
Provedor de dados: 5
Autores: Huvet, Arnaud; Herpin, Amaury; Degremont, Lionel; Labreuche, Yannick; Samain, Jean-francois; Cunningham, Charles.
Summer mortality associated with juveniles of the oyster Crassostrea gigas is probably the result of a complex interaction between the host, pathogens and environmental factors. Genetic variability in the host appears to be a major determinant in its sensitivity to summer mortality. Previously, divergent selection criteria based on summer survival have been applied to produce oyster families with resistant and susceptible progeny. In this paper, we describe the use of suppression subtractive hybridization to generate 150 C gigas clones that were differentially regulated between resistant and susceptible F2 progeny. The nucleotide sequence of these clones was determined. In 28%, the inferred amino sequence was found to match the products of known genes, 14%...
Tipo: Text
Palavras-chave: Suppression subtractive hybridization; Oysters; Differentially regulated genes; Bivalves; Bacterial challenge.
Ano: 2004
URL: http://archimer.ifremer.fr/doc/2004/publication-651.pdf

Cellular and molecular hemocyte responses of the Pacific oyster, Crassostrea gigas, following bacterial infection with Vibrio aestuarianus strain 01/32
Provedor de dados: 5
Autores: 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

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

Long dsRNAs promote an anti-viral response in Pacific oyster hampering ostreid herpesvirus 1 replication
Provedor de dados: 5
Autores: Pauletto, Marianna; Segarra, Amelie; Montagnani, Caroline; Quillien, Virgile; Faury, Nicole; Le Grand, Jacqueline; Miner, Philippe; Petton, Bruno; Labreuche, Yannick; Fleury, Elodie; Fabioux, Caroline; Bargelloni, Luca; Renault, Tristan; Huvet, Arnaud.
Double-stranded RNA (dsRNA)-mediated genetic interference (RNAi) is a widely used reverse genetic tool for determining the loss-of-function phenotype of a gene. Here, the possible induction of an immune response by long dsRNA was tested in a marine bivalve (Crassostrea gigas), as well as the specific role of the subunit 2 of the nuclear factor kappa B inhibitor (I kappa B2). This gene is a candidate of particular interest for functional investigations in the context of oyster mass mortality events, as Cg-I kappa B2 mRNA levels exhibited significant variation depending on the amount of ostreid herpesvirus 1 (OsHV-1) DNA detected. In the present study, dsRNAs targeting Cg-I kappa B2 and green fluorescent protein genes were injected in vivo into oysters...
Tipo: Text
Palavras-chave: Anti-viral response; RNA interference; Inhibitor of NF-kappa B; Marine bivalve; Ostreid herpesvirus 1.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00409/52011/52698.pdf

Evidence for the involvement of pathogenic bacteria in summer mortalities of the Pacific oyster Crassostrea gigas
Provedor de dados: 5
Autores: 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
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2406.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

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

Projet Déduction 2007-2010. Bilan par action et annexes
Provedor de dados: 5
Autores: Beliaeff, Benoit; Laugier, Thierry; Chim, Liet; Coatanea, Denis; Della Patrona, Luc; Goyard, Emmanuel; Herlin, Jose; Labreuche, Yannick; Lemaire, Pierrette; Lemonnier, Hugues; Morvan, Patrice; Patrois, Jacques; Peignon, Jean-marie; Pham, Dominique; Soulard, Benoit; Wabete, Nelly; Walling, Emilie; Ansquer, Dominique; Castex, Mathieu; Lucas, Ronan; Reynaud, Yann; Ifremer, LEAD-NC,.
Ce document constitue le bilan détaillé des résultats du projet DEDUCTION (2007-2010) , action par action. Le projet DEDUCTION "DEveloppement DUrable de la Crevetticulture, Traitement de l’Information et Observatoire du système en Nouvelle-Calédonie" est un projet de recherche et de développement en soutien à la filière crevetticole néo-calédonienne. C'est un programme très horizontal et pluridisciplinaire en poursuivant et développant les ouvertures scientifiques, techniques et thématiques établies à la faveur de DESANS. Son ossature s’articule autour de 4 actions : 3 actions de recherche et une action transversale devant faciliter les interfaces entre la recherche et sa finalité, entre les chercheurs et les partenaires locaux (GFA, Provinces,...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00199/31006/35663.pdf