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| Registros recuperados: 19 | |
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| Rolland, Jean-luc; Medhioub, Walid; Vergnes, Agnes; Abi-khalil, Celina; Savar, Veronique; Abadie, Eric; Masseret, Estelle; Amzil, Zouher; Laabir, Mohamed. |
| To better understand the effect of Paralytic Shellfish Toxins (PSTs) accumulation in the digestive gland of the Pacific oyster, Crassostrea gigas, we experimentally exposed individual oysters for 48 h to a PSTs producer, the dinoflagellate Alexandrium catenella. In comparison to the effect of the non-toxic Alexandrium tamarense, on the eight apoptotic related genes tested, Bax and BI.1 were significantly upregulated in oysters exposed 48 h to A. catenella. Among the five detoxification related genes tested, the expression of cytochrome P450 (CYP1A) was shown to be correlated with toxin concentration in the digestive gland of oysters exposed to the toxic dinoflagellate. Beside this, we observed a significant increase in ROS production, a decrease in... |
| Tipo: Text |
Palavras-chave: Shellfish; Toxin; Biomarker; Expression; Phytoplankton. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00225/33606/32003.pdf |
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| Petit, Vanessa W.; Rolland, Jean-luc; Blond, Alain; Cazevieille, Chantal; Djediat, Chakib; Peduzzi, Jean; Goulard, Christophe; Bachere, Evelyne; Dupont, Joelle; Destoumieux-garzon, Delphine; Rebuffat, Sylvie. |
| Background. Hemocyanins are respiratory proteins with multiple functions. In diverse crustaceans hemocyanins can release histidine-rich antimicrobial peptides in response to microbial challenge. In penaeid shrimp, strictly antifungal peptides are released from the C-terminus of hemocyanins. Methods. The three-dimensional structure of the antifungal peptide PvHCt from Litopenaeus vannamei was determined by NMR. Its mechanism of action against the shrimp pathogen Fusarium oxysporum was investigated using immunochemistry, fluorescence and transmission electron microscopy. Results. PvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact with F. oxysporum, PvHCt bound... |
| Tipo: Text |
Palavras-chave: Antimicrobial peptide; Amphipathic helix; Fungi; Membrane bilayer; Nuclear magnetic resonance (NMR); Fluorescence microscopy. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00301/41202/40362.pdf |
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| Rolland, Jean-luc. |
| The work reported here was motivated by the economical importance of the pacific blue shrimp Litopenaeus stylirostris farming where high mortality rates are due to bacterial and viral diseases. It consists in the characterisation of two original peptides, the first members of a new multifunctional family of peptides from peneide shrimps, the stylicines. Those two peptides, named stylicines 1 and 2, are negatively charged (pI < 6.0), and characterised by a proline-rich N-terminal region and a C-terminal region containing 13 cysteine residues. Stylicines are synthesized by heamocytes where they are stored within small cytoplasmic granules. To understand the role of these peptides in the immune response of shrimps to a vibrio infection, their recombinant... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00024/13558/10612.pdf |
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| Richard, Marion; Bec, Beatrice; Vanhuysse, Charles; Mas, Sébastien; Parin, David; Chantalat, Camila; Le Gall, Patrik; Fiandrino, Annie; Lagarde, Franck; Mortreux, Serge; Ouisse, Vincent; Rolland, Jean-luc; Degut, Anaïs; Hatey, Elise; Fortune, Martine; Roque D'Orbcastel, Emmanuelle; Messiaen, Gregory; Munaron, Dominique; Callier, Myriam; Oheix, Jocelyne; Derolez, Valerie; Mostajir, Behzad. |
| Oysters modify the planktonic microbial community structure by their filtration and NH4 excretion activities. While many studies have been conducted on this subject with adult oysters, none had been carried out in situ with juveniles. Pacific oyster juveniles (Magallana gigas, previously Crassostrea gigas) died massively all over the world since 2008 in relation with OsHV-1 infection. During mortality episodes, sick and dead oysters are not separated from healthy live ones, and left to decay in the surrounding environment, with unknown consequences for the nutrient cycle and planktonic microbial components (PMC). The present study aimed to elucidate for the first time the interactions between oyster juveniles and PMC during a mortality episode. Innovative... |
| Tipo: Text |
Palavras-chave: Magallana gigas; Crassostrea gigas; Spat; OsHV-1 mu Var; Mortality; Picoplankton; Heterotrophic flagellates; Ciliates; Uronema; Balanion. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00474/58559/61115.pdf |
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| Zappa, Sebastien; Rolland, Jean-luc; Flament, Didier; Gueguen, Yannick; Boudrant, Joseph; Dietrich, Jacques. |
| This work reports the first isolation and characterization of an alkaline phosphatase (AP) from a hyperthermophilic archaeon. An AP gene from Pyrococcus abyssi, a euryarchaeon isolated from a deep-sea hydrothermal vent, was cloned and the enzyme expressed in Escherichia coli. Analysis of the sequence showed conservation of the active site and structural elements of the E. coli AP. The recombinant AP was purified and characterized. Monomeric and homodimeric active forms were detected, with a monomer molecular mass of 54 kDa. Apparent optimum pH and temperature were estimated at 11.0 and 70 degreesC, respectively. Thus far, P. abyssi AP has been demonstrated to be the most thermostable AP, with half-lives at 100 and 105 degreesC of 18 and 5 h, respectively.... |
| Tipo: Text |
Palavras-chave: Escherichia coli; Characterization; Isolation; Gene; Alkaline phosphatase; Pyrococcus abyssi; Archaeon. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-1268.pdf |
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| Abadie, Eric; Kaci, Lamia; Berteaux, Tom; Hess, Philipp; Sechet, Veronique; Masseret, Estelle; Rolland, Jean-luc; Laabir, Mohamed. |
| ulcanodinium rugosum, a recently described dinoflagellate species producing a potent neurotoxin (pinnatoxin G), has been identified in French Mediterranean lagoons and was responsible for recurrent episodes of shellfish toxicity detected by mouse bioassay. Until now, the biology and physiology of V. rugosum have not been fully investigated. We studied the growth characteristics and toxicity of a V. rugosum strain (IFR-VRU-01), isolated in the Ingril lagoon in June 2009 (North-Western French Mediterranean Sea). It was cultivated in Enriched Natural Sea Water (ENSW) with organic (urea) and inorganic (ammonium and nitrate) nitrogen, at a temperature of 25 °C and irradiance of 100 μmol/m2·s−1. Results showed that ammonium was assimilated by cells more rapidly... |
| Tipo: Text |
Palavras-chave: Vulcanodinium rugosum; Pinnatoxin G; Ingril lagoon; Growth; Nitrogen source. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00276/38748/37290.pdf |
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| Medhioub, Walid; Ramondenc, Simon; Vanhove, Audrey; Vergnes, Agnes; Masseret, Estelle; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc. |
| This study assessed the apoptotic process occurring in the hemocytes of the Pacific oyster, Crassostrea gigas, exposed to Alexandrium catenella, a paralytic shellfish toxins (PSTs) producer. Oysters were experimentally exposed during 48 h to the toxic algae. PSTs accumulation, the expression of 12 key apoptotic-related genes, as well as the variation of the number of hemocytes in apoptosis was measured at time intervals during the experiment. Results show a significant increase of the number of hemocytes in apoptosis after 29 h of exposure. Two pro-apoptotic genes (Bax and Bax-like) implicated in the mitochondrial pathway were significantly upregulated at 21 h followed by the overexpression of two caspase executor genes (caspase-3 and caspase-7) at 29 h,... |
| Tipo: Text |
Palavras-chave: Shellfish; Toxins; Apoptosis; Gene expression. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28744/27213.pdf |
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| Abi-khalil, Celina; Lopez-joven, Carmen; Abadie, Eric; Savar, Veronique; Amzil, Zouher; Laabir, Mohamed; Rolland, Jean-luc. |
| The multifactorial etiology of massive Crassostrea gigas summer mortalities results from complex interactions between oysters, opportunistic pathogens and environmental factors. In a field survey conducted in 2014 in the Mediterranean Thau Lagoon (France), we evidenced that the development of the toxic dinoflagellate Alexandrium catenella, which produces paralytic shellfish toxins (PSTs), was concomitant with the accumulation of PSTs in oyster flesh and the occurrence of C. gigas mortalities. In order to investigate the possible role of toxic algae in this complex disease, we experimentally infected C. gigas oyster juveniles with Vibrio tasmaniensis strain LGP32, a strain associated with oyster summer mortalities, after oysters were exposed to Alexandrium... |
| Tipo: Text |
Palavras-chave: Harmful algae; Environment; Interaction; Pathogens; Defense; Paralytic shellfish toxin. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00309/42016/41308.pdf |
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| Guinand, B; Rolland, Jean-luc; Bonhomme, Francois. |
| Coastal and estuarine areas in the Bay of Biscay are essential nursery habitats for sole (Solea solea). Using three intronic markers, we investigated patterns of genetic differentiation among cohorts of juveniles (0+, 1+, sub-adults) inhabiting four major nurseries in the Vilaine and Loire river estuaries, the Pertuis d' Antioche strait, and the Gironde estuary. Genetic differentiation was not significant for the age 0- and 1-groups, but was among sub-adult samples (theta(WC) = 0.017; P = 0.031). Hierarchical analyses of genotypic frequencies by nested multivariate ANOVA using redundancy analysis indicated that northern nurseries of Loire and Vilaine rivers had different patterns of genotypic variation with age than southern nurseries of the Pertuis d'... |
| Tipo: Text |
Palavras-chave: Selection; Genetic drift; EPIC PCR; Population genetics; Coastal nurseries; Juveniles; Flatfish. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4299.pdf |
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| Farias, Natanael Dantas; Falchetti, Marcelo; Matos, Gabriel Machado; Schmitt, Paulina; Barreto, Cairé; Argenta, Nicolas; Rolland, Jean-luc; Bachère, Evelyne; Perazzolo, Luciane Maria; Rosa, Rafael Diego. |
| Stylicins are anionic antimicrobial host defense peptides (AAMPs) composed of a proline-rich N-terminal region and a C-terminal portion containing 13 conserved cysteine residues. Here, we have increased our knowledge about these unexplored crustacean AAMPs by the characterization of novel stylicin members in the most cultivated penaeid shrimp, Litopenaeus vannamei. We showed that the L. vannamei stylicin family is composed of two members (Lvan-Stylicin1 and Lvan-Stylicin2) encoded by different loci which vary in gene copy number. Unlike the other three gene-encoded antimicrobial peptide families from penaeid shrimp, the expression of Lvan-Stylicins is not restricted to hemocytes. Indeed, they are also produced by the columnar epithelial cells lining the... |
| Tipo: Text |
Palavras-chave: Crustacean; Penaeid shrimp; Invertebrate immunity; Antimicrobial peptide; Host defense peptide; Molecular diversity. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00466/57816/60102.pdf |
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| Green, Timothy J.; Rolland, Jean-luc; Vergnes, Agnes; Raftos, David; Montagnani, Caroline. |
| The host-pathogen interactions between the Pacific oyster (Crassostrea gigas) and Ostreid herpesvirus type 1 (OsHV-1) are poorly characterised. Herpesviruses are a group of large, DNA viruses that are known to encode gene products that subvert their host’s antiviral response. It is likely that OsHV-1 has also evolved similar strategies as its genome encodes genes with high homology to C. gigas inhibitors of apoptosis (IAPs) and an interferon-stimulated gene (termed CH25H). The first objective of this study was to simultaneously investigate the expression of C. gigas and OsHV-1 genes that share high sequence homology during an acute infection. Comparison of apoptosis-related genes revealed that components of the extrinsic apoptosis pathway (TNF) were... |
| Tipo: Text |
Palavras-chave: Crassostrea; Anti-viral response; Apoptosis; Interferon-like; Poly I:C. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00279/39048/37610.pdf |
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| Lopez-joven, Maria-carmen; Rolland, Jean-luc; Haffner, Philippe; Caro, Audrey; Roques, Cecile; Carre, Claire; Travers, Marie-agnes; Abadie, Eric; Laabir, Mohamed; Bonnet, Delphine; Destoumieux-garzon, Delphine. |
| Vibrio species have been associated with recurrent mass mortalities of juvenile oysters Crassostrea gigas threatening oyster farming worldwide. However, knowledge of the ecology of pathogens in affected oyster farming areas remains scarce. Specifically, there are no data regarding (i) the environmental reservoirs of Vibrio populations pathogenic to oysters, (ii) the environmental factors favoring their transmission, and (iii) the influence of oyster farming on the persistence of those pathogens. This knowledge gap limits our capacity to predict and mitigate disease occurrence. To address these issues, we monitored Vibrio species potentially pathogenic to C. gigas in 2013 and 2014 in the Thau Lagoon, a major oyster farming region in the coastal French... |
| Tipo: Text |
Palavras-chave: Vibrio; Shellfish farming; Bivalve mollusks; Mortality outbreak; Phytoplankton; Zooplankton. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00463/57479/59598.pdf |
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| Rolland, Jean-luc; Pelletier, Kevin; Masseret, Estelle; Rieuvilleneuve, Fabien; Savar, Veronique; Santini, Adrien; Amzil, Zouher. |
| The pacific oyster Crassostrea gigas was experimentally exposed to the neurotoxic Alexandrium catenella and a non-producer of PSTs, Alexandrium tamarense (control algae), at concentrations corresponding to those observed during the blooming period. At fixed time intervals, from 0 to 48 h, we determined the clearance rate, the total filtered cells, the composition of the fecal ribbons, the profile of the PSP toxins and the variation of the expression of two a-amylase and triacylglecerol lipase precursor (TLP) genes through semi-quantitative RT-PCR. The results showed a significant decrease of the clearance rate of C. gigas fed with both Alexandrium species. However, from 29 to 48 h, the clearance rate and cell filtration activity increased only in oysters... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Alexandrium catenella; PSP toxins; Digestion; Gene expression. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00130/24170/22172.pdf |
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| Rolland, Jean-luc; Bonhomme, Francois; Lagardere, Francoise; Hassan, M; Guinand, Bruno. |
| Spatial and temporal population genetic structures of the common sole, Solea solea, were studied in Northeastern Atlantic and Mediterranean Sea populations, using three polymorphic exon-primed intron-crossing (EPIC) markers. Results demonstrated significant multilocus differentiation among Eastern Mediterranean and a group composed by Western Mediterranean and Atlantic populations (theta = 0.150, P < 0.001), but also suggested unrecorded genetic differentiation of the Adriatic Sea population. No pattern of isolation-by-distance was recorded across the range covered by sampling, from the Kattegat to the Aegean Sea. Conversely to genetically structured Mediterranean populations, Atlantic populations ranging from Denmark to Portugal could be considered as... |
| Tipo: Text |
Palavras-chave: Marine fish; Genetic structure; Introns; Common sole. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2400.pdf |
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| Robino, Etienne; Poirier, Aurore C.; Amraoui, Hajar; Le Bissonnais, Sandra; Perret, Angelique; Lopez‐joven, Carmen; Auguet, Jean-christophe; Rubio, Tristan P.; Cazevieille, Chantal; Rolland, Jean-luc; Héchard, Yann; Destoumieux‐garzón, Delphine; Charrière, Guillaume. |
| ibrios are ubiquitous in marine environments and opportunistically colonize a broad range of hosts. Strains of Vibrio tasmaniensis present in oyster farms can thrive in oysters during juvenile mortality events and behave as facultative intracellular pathogen of oyster hemocytes. Herein, we wondered whether V. tasmaniensis LGP32 resistance to phagocytosis is specific to oyster immune cells or contributes to resistance to other phagocytes, like marine amoebae. To address this question, we developed an integrative study, from the first description of amoeba diversity in oyster‐farms to the characterization of LGP32 interactions with amoebae. An isolate of the Vannella genus, Vannella sp. AP1411, which was collected from oyster farms, is ubiquitous, and... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00509/62109/66292.pdf |
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| Rolland, Jean-luc; Abdelouahab, Mahdia; Dupont, J.; Lefevre, F.; Bachere, Evelyne; Romestand, Bernard. |
| The present study reports the characterization of Ls-Stylicin1, a novel antimicrobial peptide from the penaeid shrimp, Litopenoeus stylirostris. The predicted mature peptide of 82 residues is negatively charged (theoretical pl=5.0) and characterized by a proline-rich N-terminal region and a C-terminal region containing 13 cysteine residues. The recombinant Ls-Stylicin1 has been isolated in both monomeric and dimeric forms. Both display strong antifungal activity against Fusarium oxysporum (1.25 mu M < MIC <2.5 mu M), a pathogenic fungus of shrimp, but lower antimicrobial activity against Gram () bacteria, Vibrio sp. (40 mu M < MIC <80 mu M). However, rLs-Stylicin1 is able to agglutinate Vibrio pennaeicidae in vitro in agreement with its potent... |
| Tipo: Text |
Palavras-chave: Ls-Stylicin 1; Peptide; Shrimp; Antifungal; Agglutination; Vibrio. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00003/11387/8094.pdf |
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| Abikhalil, Celina; Finkelstein, Darren S.; Conejero, Genevieve; Du Bois, Justin; Destoumieux-garzon, Delphine; Rolland, Jean-luc. |
| Exposure of the toxin-producing dinoflagellate Alexandrium catenella (A. catenella) was previously demonstrated to cause apoptosis of hemocytes in the oyster species Crassostrea gigas. In this work, a coumarin-labeled saxitoxin appeared to spread throughout the cytoplasm of the hemocytes. PSTs, including saxitoxin, were also shown to be directly responsible for inducing apoptosis in hemocytes, a process dependent on caspase activation and independent of reactive oxygen species (ROS) production. A series of in vitro labeling and microscopy experiments revealed that STX and analogs there of induced nuclear condensation, phosphatidylserine exposure, membrane permeability, and DNA fragmentation of hemocytes. Unlike in vertebrates, gonyautoxin-5 (GTX5), which... |
| Tipo: Text |
Palavras-chave: Shellfish; Toxin; Harmful algae; Phytoplankton. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00391/50272/50905.pdf |
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| Hadjadji, Imen; Laabir, Mohamed; Frihi, Hocine; Collos, Yves; Shao, Zhao Jun; Berrebi, Patrick; Abadie, Eric; Amzil, Zouher; Chomérat, Nicolas; Rolland, Jean-luc; Rieuvilleneuve, Fabien; Masseret, Estelle. |
| Physiological plasticity gives HABs species the ability to respond to variations in the surrounding environment. The aim of this study was to examine morphological and physiological variability in Alexandrium pacificum R.W. Litaker (Group IV) (former Alexandrium catenella) blooming in Annaba bay, Algeria. Monoclonal cultures of up to 30 strains of this neurotoxic dinoflagellate were established by the germination of single resting cysts from the surface sediment of this southern Mediterranean marine ecosystem. Ribotyping confirmed formally for the first time that A. pacificum is developing in Eastern Algerian waters. Toxin analyses of A. pacificum strains revealed substantial intraspecific variability in both the profile and toxin amount. However, the... |
| Tipo: Text |
Palavras-chave: Alexandrium pacificum; Mediterranean; Toxin profile; Growth; Intraspecific variability. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73620/73598.pdf |
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| Registros recuperados: 19 | |
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