Consulta: creatorFacets:"Gueguen, Yannick"
Registros recuperados: 57
Data/hora: 09/06/2024 01:58:42

Characterization of molecular processes involved in the pearl formation in Pinctada margaritifera for a sustainable development of pearl farming industry in French Polynesia
Provedor de dados: 5
Autores: Gueguen, Yannick; Montagnani, Caroline; Joubert, Caroline; Marie, Benjamin; Belliard, Corinne; Tayale, Alexandre; Fievet, Julie; Levy, Peva; Piquemal, David; Marin, Frederic; Le Moullac, Gilles; Ky, Chin-long; Garen, Pierre; Lo, Cedrick; Saulnier, Denis.
Tahiti’s pearl farming industry plays a major socio-economic role in French Polynesia. In an increasingly competitive market where the production of high quality pearls becomes essential, research can help secure and ensure sustainable production. In that context, Ifremer, in close collaboration with the “direction des resources marines” (French Polynesian government agency) has developed research projects on the “sustainable development of pearl farming”. This program is organized along 3 axes: (1) understanding the animal physiology and initiating a genetically selective breeding program of donor oysters; (2) understanding pearl oyster larvae dispersal and recruitment; (3) understanding the molecular mechanisms underlying biomineralization processes...
Tipo: Text
Palavras-chave: Pearl oyster; Biomineralization; Pinctada margaritifera.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00167/27840/26049.pdf

Expression, tissue localization and synergy of antimicrobial peptides and proteins in the immune response of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Schmitt, Paulina; De Lorgeril, Julien; Gueguen, Yannick; Destoumieux-garzon, Delphine; Bachere, Evelyne.
Diverse families of antimicrobial peptides and proteins have been described in oysters. We investigated here how antimicrobials are involved in the immune response against a pathogenic strain of Vibrio splendidus. Oyster antimicrobials were shown to display a wide variety of expression profiles in hemocyte populations and tissues. Oyster defensins are constitutively expressed in specific tissues such as mantle (Cg-Defm) or hemocytes (Cg-Defhs), while Cg-BPI is inducible and Cg-Prp appears down-regulated in hemocytes upon infection. The migratory behavior of hemocytes that express the different antimicrobials was found to be involved in the oyster response to a pathogenic Vibrio infection. Indeed, it contributes to colocalize several antimicrobials that...
Tipo: Text
Palavras-chave: Pacific oyster; Bivalve mollusk; Innate immunity; Bactericidal/permeability-increasing protein; Proline-rich peptide; Defensin; Vibrio.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00093/20382/18267.pdf

Generation and analysis of a 29,745 unique Expressed Sequence Tags from the Pacific oyster (Crassostrea gigas) assembled into a publicly accessible database: the GigasDatabase
Provedor de dados: 5
Autores: Fleury, Elodie; Huvet, Arnaud; Lelong, Christophe; De Lorgeril, Julien; Boulo, Viviane; Gueguen, Yannick; Bachere, Evelyne; Tanguy, Arnaud; Moraga, Dario; Fabioux, Caroline; Lindeque, Penelope; Shaw, Jenny; Reinhardt, Richard; Prunet, Patrick; Davey, Grace; Lapegue, Sylvie; Sauvage, Christopher; Corporeau, Charlotte; Moal, Jeanne; Gavory, Frederick; Wincker, Patrick; Moreews, Francois; Klopp, Christophe; Mathieu, Michel; Boudry, Pierre; Favrel, Pascal.
Background: Although bivalves are among the most-studied marine organisms because of their ecological role and economic importance, very little information is available on the genome sequences of oyster species. This report documents three large-scale cDNA sequencing projects for the Pacific oyster Crassostrea gigas initiated to provide a large number of expressed sequence tags that were subsequently compiled in a publicly accessible database. This resource allowed for the identification of a large number of transcripts and provides valuable information for ongoing investigations of tissue-specific and stimulus-dependant gene expression patterns. These data are crucial for constructing comprehensive DNA microarrays, identifying single nucleotide...
Tipo: Text
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6770.pdf

Microbiota Composition and Evenness Predict Survival Rate of Oysters Confronted to Pacific Oyster Mortality Syndrome
Provedor de dados: 5
Autores: Clerissi, Camille; De Lorgeril, Julien; Petton, Bruno; Lucasson, Aude; Escoubas, Jean Michel; Gueguen, Yannick; Dégremont, Lionel; Mitta, Guillaume; Toulza, Eve.
Pacific Oyster Mortality Syndrome (POMS) affects Crassostrea gigas oysters worldwide and causes important economic losses. Disease dynamic was recently deciphered and revealed a multiple and progressive infection caused by the Ostreid herpesvirus OsHV-1 μVar, triggering an immunosuppression followed by microbiota destabilization and bacteraemia by opportunistic bacterial pathogens. However, it remains unknown if microbiota might participate to protect oysters against POMS, and if microbiota characteristics might be predictive of oyster mortalities. To tackle this issue, we transferred full-sib progenies of resistant and susceptible oyster families from hatchery to the field during a period in favor of POMS. After 5 days of transplantation, oysters from...
Tipo: Text
Palavras-chave: Holobiont; Microbiome; Metabarcoding; Fitness; Bacteria.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00621/73332/72500.pdf

Molecular detection of betanodavirus from the farmed fish, Platax orbicularis (Forsskal) (Ephippidae), in French Polynesia
Provedor de dados: 5
Autores: David, R.; Treguier, Cathy; Montagnani, Caroline; Belliard, Corinne; Levy, Peva; Nedelec, Georges; Joufoques, Vaiana; Remoissenet, G.; Gueguen, Yannick; Cochennec-laureau, Nathalie.
Tipo: Text
Palavras-chave: Betanodavirus; Detection; French Polynesia; Genotype; Platax orbicularis.
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00003/11380/7972.pdf

Rearing effect of biofloc on antioxidant and antimicrobial transcriptional response in Litopenaeus stylirostris shrimp facing an experimental sub-lethal hydrogen peroxide stress
Provedor de dados: 5
Autores: Cardona, Emilie; Saulnier, Denis; Lorgeoux, Benedicte; Chim, Liet; Gueguen, Yannick.
This study compares the antioxidant and antimicrobial transcriptional expression of blue shrimps reared according to two different systems, BioFloc Technology (BFT) and Clear sea Water (CW) and their differential responses when facing an experimental sublethal hydrogen peroxide stress. After 30 days of rearing, juvenile shrimps were exposed to H2O2 stress at a concentration of 30 ppm during 6 hours. The oxidative stress caused by H2O2 was examined in the digestive glands of the shrimp, in which antioxidant enzyme (AOE) and antimicrobial peptide (AMP) gene expression were analysed by quantitative real-time PCR. Results showed that rearing conditions did not affect the expression of genes encoding AOEs or AMPs. However, H2O2 stress induced a differential...
Tipo: Text
Palavras-chave: Biofloc; Shrimps; Antimicrobial peptides; Antioxidant enzymes.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00270/38116/36269.pdf

Gonad transcriptome analysis of pearl oyster Pinctada margaritifera: identification of potential sex differentiation and sex determining genes
Provedor de dados: 5
Autores: Teaniniuraitemoana, Vaihiti; Huvet, Arnaud; Levy, Peva; Klopp, Christophe; Lhuillier, Emeline; Gaertner-mazouni, Nabila; Gueguen, Yannick; Le Moullac, Gilles.
Background  Black pearl farming is based on culture of the blacklip pearl oyster Pinctada margaritifera (Mollusca, lophotrochozoa), a protandrous hermaphrodite species. At first maturation, all individuals are males. The female sex appears progressively from two years old, which represents a limitation for broodstock conditioning for aquaculture production. In marine mollusks displaying hermaphroditic features, data on sexual determinism and differentiation, including the molecular sex determining cascade, are scarce. To increase genomic resources and identify the molecular mechanisms whereby gene expression may act in the sexual dimorphism of P. margaritifera, we performed gonad transcriptome analysis.  Results  The gonad transcriptome of P. margaritifera...
Tipo: Text
Palavras-chave: Pinctada margaritifera; Gametogenesis; Transcriptome; Differential expression; Sex determinism.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00201/31194/29593.pdf

Determination of gender in the pearl oyster pinctada margaritifera
Provedor de dados: 5
Autores: Chavez-villalba, Jorge; Soyez, Claude; Huvet, Arnaud; Gueguen, Yannick; Lo, Cedrik; Le Moullac, Gilles.
The pearl industry in French Polynesia is based on exploitation of natural stocks of the black-lip pearl oyster (Pinctada margaritifera); it generates an annual turnover of 90 million euros. Improvements in pearl quality need genetic studies to improve the populations. This pearl oyster is a protandric species, where the sex-ratio normally is biased towards males. There is an increasing interest in gender control to find the mechanisms to augment female proportions for management purposes. This review summarizes information on exogenous and endogenous factors regulating gender in this and other bivalves and concludes that P. margaritifera is a protandric hermaphrodite, developing as a male during the first two years and without evidence of an effect from...
Tipo: Text
Palavras-chave: Pearl oyster; Pinctada; Hermaphrodite; Temperature; Food; Stress; Sex genes; Sex steroids.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00040/15100/12543.pdf

Yes, it turns: experimental evidence of pearl rotation during its formation
Provedor de dados: 5
Autores: Gueguen, Yannick; Czorlich, Yann; Mastail, Max; Le Tohic, Bruno; Defay, Didier; Lyonnard, Pierre; Marigliano, Damien; Gauthier, Jean-pierre; Bari, Hubert; Lo, Cedrik; Chabrier, Sebastien; Le Moullac, Gilles.
Cultured pearls are human creations formed by inserting a nucleus and a small piece of mantle tissue into a living shelled mollusc, usually a pearl oyster. Although many pearl observations intuitively suggest a possible rotation of the nucleated pearl inside the oyster, no experimental demonstration of such a movement has ever been done. This can be explained by the difficulty of observation of such a phenomenon in the tissues of a living animal. To investigate this question of pearl rotation, a magnetometer system was specifically engineered to register magnetic field variations with magnetic sensors from movements of a magnetic nucleus inserted in the pearl oyster. We demonstrated that a continuous movement of the nucleus inside the oyster starts after a...
Tipo: Text
Palavras-chave: Pearl oyster; Pearl rotation; Biomineralization.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00275/38598/37127.pdf

Evidence of donor effect on cultured pearl quality from a duplicated grafting experiment on Pinctada margaritifera using wild donors
Provedor de dados: 5
Autores: Tayale, Alexandre; Gueguen, Yannick; Treguier, Cathy; Le Grand, Jacqueline; Cochennec-laureau, Nathalie; Montagnani, Caroline; Ky, Chin-long.
Producing high quality cultured black pearls from Pinctada margaritifera is one of the major challenges for the "pearl oyster" industry in French Polynesia. In order to assess donor effect on cultured pearl quality, wild Pinctada margaritifera originating from the Tuamotu Archipelago were used in a duplicated grafting experiment. After 12 months of culture, nucleus retention was assessed and seven pearl quality traits recorded on the 454 cultured pearls harvested from the experiment. The traits scored were nacre thickness and pearl weight, surface defects, lustre, grade, and the colour components: 1) darkness of cultured pearl colour, and 2) visual perception of colour class (bodycolor and/or overtone). Our results demonstrate for the first time that...
Tipo: Text
Palavras-chave: Cultured pearl oyster; Pearl quality; Nacre; Donor mollusc; Genetic selection; Pteriidae; Blacklip pearl oyster; Pinctada margaritifera; French Polynesia.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00116/22757/20541.pdf

Identification of genes associated with shell color in the black-lipped pearl oyster, Pinctada margaritifera
Provedor de dados: 5
Autores: Lemer, Sarah; Saulnier, Denis; Gueguen, Yannick; Planes, Serge.
Background: Color polymorphism in the nacre of pteriomorphian bivalves is of great interest for the pearl culture industry. The nacreous layer of the Polynesian black-lipped pearl oyster Pinctada margaritifera exhibits a large array of color variation among individuals including reflections of blue, green, yellow and pink in all possible gradients. Although the heritability of nacre color variation patterns has been demonstrated by experimental crossing, little is known about the genes involved in these patterns. In this study, we identify a set of genes differentially expressed among extreme color phenotypes of P. margaritifera using a suppressive and subtractive hybridization (SSH) method comparing black phenotypes with full and half albino individuals....
Tipo: Text
Palavras-chave: Differential expression; Biomineralization; Nacre; Pearl; Pigmentation; Albino.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00275/38627/37167.pdf

Calcein staining of calcified structures in pearl oyster Pinctada margaritifera and the effect of food resource level on shell growth
Provedor de dados: 5
Autores: Linard, Clementine; Gueguen, Yannick; Moriceau, Jacques; Soyez, Claude; Hui, Belinda; Raoux, Aurore; Cuif, Jean Pierre; Cochard, Jean-claude; Le Pennec, Marcel; Le Moullac, Gilles.
Marine mollusc shell growth has been widely measured using fluorochrome marking. In order to test the efficiency and reliability of calcein staining on P. margaritifera shells and pearls, the present study examined two administration methods, different concentrations and several immersion times.Immersion in a 150 mg.L-1 calcein solution for 12 h to 24 h appeared to be the best method for marking P. margaritifera shells. For pearl marking, injection of a 200 mg.L-1 calcein solution into the pearl pouch was the optimal method. Calcein marking was then used to measure the influence of food resource levels on the shell growth. Groups of 23-month-old P. margaritifera were fed at three trophic levels for two months. The two highest food levels tested (6 000...
Tipo: Text
Palavras-chave: Bivalvia; Pearl; Shell; Growth; Scanning electron microscope.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00028/13907/11195.pdf

Bacterial community characterization of water and intestine of the shrimp Litopenaeus stylirostris in a biofloc system
Provedor de dados: 5
Autores: Cardona, Emilie; Gueguen, Yannick; Magré, Kevin; Lorgeoux, Bénédicte; Piquemal, David; Pierrat, Fabien; Noguier, Florian; Saulnier, Denis.
Background  Biofloc technology (BFT), a rearing method with little or no water exchange, is gaining popularity in aquaculture. In the water column, such systems develop conglomerates of microbes, algae and protozoa, together with detritus and dead organic particles. The intensive microbial community presents in these systems can be used as a pond water quality treatment system, and the microbial protein can serve as a feed additive. The current problem with BFT is the difficulty of controlling its bacterial community composition for both optimal water quality and optimal shrimp health. The main objective of the present study was to investigate microbial diversity of samples obtained from different culture environments (Biofloc technology and clear...
Tipo: Text
Palavras-chave: Shrimp; Biofloc; Clear sea water; Bacterial communities; Culture environment; Microbiota.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00346/45694/45314.pdf

Des enzymes pour l'industrie
Provedor de dados: 5
Autores: Querellou, Joel; Gueguen, Yannick; Barbier, Georges; Dietrich, Jacques.
Tipo: Text
Ano: 1999
URL: http://archimer.ifremer.fr/doc/00092/20334/18037.pdf

A relationship between antimicrobial peptide gene expression and capacity of a selected shrimp line to survive a Vibrio infection
Provedor de dados: 5
Autores: De Lorgeril, Julien; Gueguen, Yannick; Goarant, Cyrille; Goyard, Emmanuel; Mugnier, Chantal; Fievet, Julie; Piquemal, D; Bachere, Evelyne.
Understanding of antimicrobial defence mechanisms of penaeid shrimp should help in the design of efficient strategies for the management and disease control in aquaculture. In this study, we have specifically analysed the expression in circulating hemocytes of antimicrobial peptides (AMPs) encoding genes, such as PEN2 and PEN3, ALF, crustin, lysozyme and a putative cysteine-rich peptide. We evidenced a relationship between the level of expression of some AMPs and the successful response of the shrimp, Litopenaeus stylirostris, to circumvent a pathogenic Vibrio penaeicida infection. Additionally, significant differences in some AMP transcript amounts are evidenced between control, non-selected shrimp line and the third generation breeding of shrimp selected...
Tipo: Text
Palavras-chave: Real time PCR; Cysteine rich peptide; Crustin; Anti LPS factor; Lysozyme; Penaeidins; Immune response; Vibrio penaeicida; Penaeid; Decapoda; Crustacean.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4524.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

Comprendre et prédire les maladies multifactorielles de bivalves marins : le cas de l’huître
Provedor de dados: 5
Autores: De Lorgeril, Julien; Gueguen, Yannick; Mitta, Guillaume.
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00487/59821/62964.pdf

A pearl of a partnership
Provedor de dados: 5
Autores: Gueguen, Yannick; Mazouni, Nabila.
Pearl farming is essential to the economy of French Polynesia, generating thousands of jobs for the islands. What are the main concerns for the current state of pearl farming in the region ?
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00188/29925/28393.pdf

Characterization of MRNP34, a novel methionine-rich nacre protein from the pearl oysters
Provedor de dados: 5
Autores: Marie, Benjamin; Joubert, Caroline; Belliard, Corinne; Tayale, Alexandre; Zanella-cleon, Isabelle; Marin, Frederic; Gueguen, Yannick; Montagnani, Caroline.
Nacre of the Pinctada pearl oyster shells is composed of 98% CaCO3 and 2% organic matrix. The relationship between the organic matrix and the mechanism of nacre formation currently constitutes the main focus regarding the biomineralization process. In this study, we isolated a new nacre matrix protein in P. margaritifera and P. maxima, we called Pmarg- and Pmax-MRNP34 (methionine-rich nacre protein). MRNP34 is a secreted hydrophobic protein, which is remarkably rich in methionine, and which is specifically localised in mineralizing the epithelium cells of the mantle and in the nacre matrix. The structure of this protein is drastically different from those of the other nacre proteins already described. This unusual methionine-rich protein is a new member in...
Tipo: Text
Palavras-chave: Matrix protein; Methionine-rich; Biomineralization; Mollusc; Nacre; Calcifying mantle.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00077/18870/16645.pdf

Characterization of a defensin from the oyster Crassostrea gigas - Recombinant production, folding, solution structure, antimicrobial activities, and gene expression
Provedor de dados: 5
Autores: Gueguen, Yannick; Herpin, Amaury; Aumelas, André; Garnier, Julien; Fievet, Julie; Escoubas, Jean-michel; Bulet, Philippe; Gonzalez, Marcelo; Lelong, Christophe; Favrel, Pascal; Bachere, Evelyne.
In invertebrates, defensins were found in arthropods and in the mussels. Here, we report for the first time the identification and characterization of a defensin (Cg-Def) from an oyster. Cg-def mRNA was isolated from Crassostrea gigas mantle using an expressed sequence tag approach. To gain insight into potential roles of Cg-Def in oyster immunity, we produced the recombinant peptide in Escherichia coli, characterized its antimicrobial activities, determined its solution structure by NMR spectroscopy, and quantified its gene expression in vivo following bacterial challenge of oysters. Recombinant Cg-Def was active in vitro against Gram-positive bacteria but showed no or limited activities against Gram-negative bacteria and fungi. The activity of Cg-Def was...
Tipo: Text
Palavras-chave: Crassostrea gigas; Genomic library; Microbiology; Defensin; Oyster.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2127.pdf

Oyster hemocytes express a proline-rich peptide displaying synergistic antimicrobial activity with a defensin
Provedor de dados: 5
Autores: Gueguen, Yannick; Romestand, Bernard; Fievet, Julie; Schmitt, Paulina; Destoumieux Garzon, Delphine; Franck, Vandenbulcke; Philippe, Bulet; Bachere, Evelyne.
A cDNA sequence that encodes a 61-amino acid polypeptide precursor with homologies to proline-rich antimicrobial peptides (AMPs) was identified in the oyster Crassostrea gigas. After release of a hydrophobic signal peptide. the resulting 37-amino acid peptide, Cg-Prp, is composed of an acidic region and a cationic proline-rich region. To evaluate the biological properties of Cg-Prp, multiple proline-rich peptides corresponding to putative processing of the full-length Cg-Prp were synthesized. A limited antimicrobial activity was observed for two of them, which also showed strong synergistic antimicrobial activity with Cg-Def, a defensin from C gigas. To our knowledge, this is the first evidence of synergy between a defensin and another AMP in an...
Tipo: Text
Palavras-chave: Antimicrobial peptide; Mollusk; Synergy; Invertebrate; Innate immunity; Pacific oyster.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6232.pdf

Relative contribution of natural productivity and compound feed to tissue growth in blue shrimp (Litopenaeus stylirostris) reared in biofloc: Assessment by C and N stable isotope ratios and effect on key digestive enzymes
Provedor de dados: 5
Autores: Cardona, Emilie; Lorgeoux, Benedicte; Geffroy, Claire; Richard, Pierre; Saulnier, Denis; Gueguen, Yannick; Guillou, Gael; Chim, Liet.
The aim of this study was to assess the relative contribution of natural productivity and compound food to the growth of the juvenile blue shrimp Litopenaeus stylirostris reared in a biofloc system. Two experiments were carried out based on the same protocol with three treatments: clear water with experimental diet (CW), biofloc with experimental diet (BF) and biofloc unfed (BU). Shrimp survival was significantly higher in biofloc rearing than in CW rearing. The contribution of the biofloc to shrimp diet was estimated through measurement of carbon and nitrogen stable isotope ratios in shrimp and food sources. Different isotopic compositions between feeds were obtained by feeding natural productivity with a mixture rich in fish meal and the shrimps with a...
Tipo: Text
Palavras-chave: Biofloc; Shrimps; Stable isotope; Digestive enzyme activities; Digestive enzyme mRNA level.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00271/38242/37241.pdf

Temperature and Food Influence Shell Growth and Mantle Gene Expression of Shell Matrix Proteins in the Pearl Oyster Pinctada margaritifera
Provedor de dados: 5
Autores: Joubert, Caroline; Linard, Clementine; Le Moullac, Gilles; Soyez, Claude; Saulnier, Denis; Teaniniuraitemoana, Vaihiti; Ky, Chin-long; Gueguen, Yannick.
In this study, we analyzed the combined effect of microalgal concentration and temperature on the shell growth of the bivalve Pinctada margaritifera and the molecular mechanisms underlying this biomineralization process. Shell growth was measured after two months of rearing in experimental conditions, using calcein staining of the calcified structures. Molecular mechanisms were studied though the expression of 11 genes encoding proteins implicated in the biomineralization process, which was assessed in the mantle. We showed that shell growth is influenced by both microalgal concentration and temperature, and that these environmental factors also regulate the expression of most of the genes studied. Gene expression measurement of shell matrix protein...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00210/32095/30535.pdf

Pinctada margaritifera responses to temperature and pH: Acclimation capabilities and physiological limits
Provedor de dados: 5
Autores: Le Moullac, Gilles; Soyez, Claude; Latchere, Oihana; Vidal-dupiol, Jeremie; Fremery, Juliette; Saulnier, Denis; Lo Yat, Alain; Belliard, Corinne; Mazouni-gaertner, Nabila; Gueguen, Yannick.
The pearl culture is one of the most lucrative aquacultures worldwide. In many South Pacific areas, it depends on the exploitation of the pearl oyster Pinctada margaritifera and relies entirely on the environmental conditions encountered in the lagoon. In this context, assessing the impact of climatic stressors, such as global warming and ocean acidification, on the functionality of the resource in terms of renewal and exploitation is fundamental. In this study, we experimentally addressed the impact of temperature (22, 26, 30 and 34 °C) and partial pressure of carbon dioxide pCO2 (294, 763 and 2485 μatm) on the biomineralization and metabolic capabilities of pearl oysters. While the energy metabolism was strongly dependent on temperature, results showed...
Tipo: Text
Palavras-chave: Global change; Pearl oyster; Bioenergetic; Biomineralization; Pacific ocean; French Polynesia.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00332/44364/43969.pdf

Effect of temperature, food availability, and estradiol injection on gametogenesis and gender in the pearl oyster     Pinctada margaritifera
Provedor de dados: 5
Autores: Teaniniuraitemoana, Vaihiti; Lepretre, Maxime; Levy, Peva; Vanaa, Vincent; Parrad, Sophie; Gaertner-mazouni, Nabila; Gueguen, Yannick; Huvet, Arnaud; Le Moullac, Gilles.
The black-lip pearl oyster Pinctada margaritifera is a protandrous hermaphrodite species. Its economic value has led to the development of controlled hatchery reproduction techniques, although many aspects remain to be optimized. In order to understand reproductive mechanisms and their controlling factors, two independent experiments were designed to test hypotheses of gametogenesis and sex ratio control by environmental and hormonal factors. In one, pearl oysters were exposed under controlled conditions at different combinations of temperature (24 and 28°C) and food level (10,000 and 40,000 cells mL−1); whereas in the other, pearl oysters were conditioned under natural conditions into the lagoon and subjected to successive 17β-estradiol injections (100 μg...
Tipo: Text
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00285/39638/38184.pdf

Transcriptome and proteome analysis of Pinctada margaritifera calcifying mantle and shell: focus on biomineralization
Provedor de dados: 5
Autores: Joubert, Caroline; Piquemal, David; Marie, Benjamin; Manchon, Laurent; Pierrat, Fabien; Zanella-cleon, Isabelle; Cochennec-laureau, Nathalie; Gueguen, Yannick; Montagnani, Caroline.
Background: The shell of the pearl-producing bivalve Pinctada margaritifera is composed of an organic cell-free matrix that plays a key role in the dynamic process of biologically-controlled biomineralization. In order to increase genomic resources and identify shell matrix proteins implicated in biomineralization in P. margaritifera, high-throughput Expressed Sequence Tag (EST) pyrosequencing was undertaken on the calcifying mantle, combined with a proteomic analysis of the shell. Results: We report the functional analysis of 276 738 sequences, leading to the constitution of an unprecedented catalog of 82 P. margaritifera biomineralization-related mantle protein sequences. Components of the current "chitin-silk fibroin gel-acidic macromolecule" model of...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00020/13154/10202.pdf

Molecular characterization of two isoforms of defensin from hemocytes of the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Gonzalez, Marcelo; Gueguen, Yannick; Desserre, Geraldine; De Lorgeril, Julien; Romestand, Bernard; Bachere, Evelyne.
Antimicrobial peptides (AMPs) are important components of the host innate immune response against microbial invasion. We previously characterized the first AMP from an oyster, a defensin, that was shown to be continuously expressed in the mantle of Crassostrea gigas. In this study, we report the cDNA cloning of two new isoforms of the defensin AMP family (Cg-defh1 and Cg-defh2) from the hemocytes of the oyster. The deduced amino acid sequences reveal two peptides of 73 amino acid residues with a mature portion consisting of 43 amino acid residues. Cy-Defh1 and CyDefh2 share 86% amino acid identity and belong to the "arthropod-molluscs defensin family". qRT-PCR analyses indicate that Cg-defh2 is continuously expressed in the hemocytes of C. gigas. In...
Tipo: Text
Palavras-chave: Defensin; Antimicrobial peptide; Hemocytes; Pacific oyster; Marine invertebrate; Mollusc bivalve.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2331.pdf

NMR Structure of rALF-Pm3, an Anti-Lipopolysaccharide Factor from Shrimp: Model of the Possible Lipid A-Binding Site
Provedor de dados: 5
Autores: Yang, Yinshan; Boze, Helene; Chemardin, Patrick; Padilla, Andre; Moulin, Guy; Tassanakajon, Anchalee; Pugniere, Martine; Roquet, Francoise; Destoumieux Garzon, Delphine; Gueguen, Yannick; Bachere, Evelyne; Aumelas, Andre.
The anti-lipopolysaccharide factor ALF-Pm3 is a 98-residue protein identified in hemocytes from the black tiger shrimp Penaeus monodon. It was expressed in Pichia pastoris from the constitutive glyceraldehyde-3-phosphate dehydrogenase promoter as a folded and N-15 uniformly labeled rALF-Pm3 protein. Its 3D structure was established by NMR and consists of three alpha-helices packed against a four-stranded beta-sheet. The C-34-C-55 disulfide bond was shown to be essential for the structure stability. By using surface plasmon resonance, we demonstrated that rALF-Pm3 binds to LPS, lipid A and to OM(R)-174, a soluble analogue of lipid A. Biophysical studies of rALF-Pm3/LPS and rALF-Pm3/OM(R)-174 complexes indicated rather high molecular sized aggregates, which...
Tipo: Text
Palavras-chave: Ultracentrifugation; Surface plasmon resonance; Septic shock; Structure; NMR; Lipid A; Lipopolysaccharide; Anti lipopolysaccharide factor.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6320.pdf

Evidence of a bactericidal permeability increasing protein in an invertebrate, the Crassostrea gigas Cg-BPI
Provedor de dados: 5
Autores: Gonzalez, Marcelo; Gueguen, Yannick; Destoumieux Garzon, Delphine; Romestand, Bernard; Fievet, Julie; Pugniere, M; Roquet, F; Escoubas, Jean-michel; Vandenbulcke, F; Levy, O; Saune, Laure; Bulet, P; Bachere, Evelyne.
A cDNA sequence with homologies to members of the LPS-binding protein and bactericidal/permeability-increasing protein (BPI) family was identified in the oyster Crassostrea gigas. The recombinant protein was found to bind LIPS, to display bactericidal activity against Escherichia coli, and to increase the permeability of the bacterial cytoplasmic membrane. This indicated that it is a BPI rather than an LPS-binding protein. By in situ hybridization, the expression of the C gigas BPI (Cg-bpi) was found to be induced in hemocytes after oyster bacterial challenge and to be constitutive in various epithelia of unchallenged oysters. Thus, Cg-bpi transcripts were detected in the epithelial cells of tissues/organs in contact with the external environment (mantle,...
Tipo: Text
Palavras-chave: Oyster innate immunity; Mollusk; Hemocyte; Epithelia; Antimicrobial.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-3564.pdf

Evidence in oyster of a plasma extracellular superoxide dismutase which binds LPS
Provedor de dados: 5
Autores: Gonzalez, Marcelo; Romestand, Bernard; Fievet, Julie; Huvet, Arnaud; Lebart, M; Gueguen, Yannick; Bachere, Evelyne.
We have characterized in the oyster Crassostrea gigas an extracellular superoxide dismutase (Cg-EcSOD) which appears to bind lipopolysaccharides (LPS). The protein has been purified from the oyster plasma and identified as a Cu/ZnSOD according to its N-terminal sequencing and biological activity. Cg-EcSOD expression and synthesis are restricted to hemocytes as revealed by in situ hybridization and immunocytochemistry. Cg-EcSOD-expressing hemocytes were seen in blood circulation, in connective tissues, and closely associated to endothelium blood vessels. Cg-EcSOD presents in its amino acid sequence a LPS-binding motif found in the endotoxin receptor CD14 and we show that the protein displays an affinity to Escherichia coli bacteria and with LPS and Lipid A....
Tipo: Text
Palavras-chave: Beta integrin; Oxidative burst; Hemocyte; Crassostrea gigas; Invertebrate; Mollusc bivalve.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-3583.pdf

Molecular Signatures Discriminating the Male and the Female Sexual Pathways in the Pearl Oyster Pinctada margaritifera
Provedor de dados: 5
Autores: Teaniniuraitemoana, Vaihiti; Huvet, Arnaud; Levy, Peva; Gaertner-mazouni, Nabila; Gueguen, Yannick; Le Moullac, Gilles.
The genomics of economically important marine bivalves is studied to provide better understanding of the molecular mechanisms underlying their different reproductive strategies. The recently available gonad transcriptome of the black-lip pearl oyster Pinctada margaritifera is a novel and powerful resource to study these mechanisms in marine mollusks displaying hermaphroditic features. In this study, RNAseq quantification data of the P. margaritifera gonad transcriptome were analyzed to identify candidate genes in histologically-characterized gonad samples to provide molecular signatures of the female and male sexual pathway in this pearl oyster. Based on the RNAseq data set, stringent expression analysis identified 1,937 contigs that were differentially...
Tipo: Text
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00256/36768/35374.pdf

Non‐invasive functional exploration techniques for bivalves with applications to pearl oyster   Pinctada margaritifera
Provedor de dados: 5
Autores: Le Moullac, Gilles; Soyez, Claude; Lyonnard, Pierre; Chabrier, Sébastien; Milhade, Leo; Gueguen, Yannick; Beliaeff, Benoit.
Non‐invasive functional exploration techniques can provide information on different aspects of general organism functioning and, unlike lethal or invasive techniques, allow individual organisms to be monitored for as long as necessary. For bivalves, a fairly wide variety of methods and instrumental means exist allowing physiology to be assessed on‐line while keeping animals alive and intact. The current range of non‐invasive techniques for bivalves consists of systems for measuring metabolic flows and valve activity, which can be used on bivalve molluscs for as long as an individual animal's characteristics (e.g. size) make this technically feasible. In this paper, we present some of these non‐invasive techniques with applications for pearl oyster and list...
Tipo: Text
Palavras-chave: Bivalve; Filtration; Pearl rotation; Respiration; Valvometry.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00599/71161/69551.pdf

Influence of farmed pearl oysters and associated biofouling communities on nutrient regeneration in lagoons of French Polynesia
Provedor de dados: 5
Autores: Lacoste, Elise; Gueguen, Yannick; Le Moullac, Gilles; Koua, Manaarii Sham; Gaertner-mazouni, Nabila.
Bivalve cultivation can significantly contribute to nutrient cycling in semi-enclosed ecosystems. We investigated the influence of suspended pearl oyster culture on nutrient regeneration in the water column of 3 oligotrophic lagoons in French Polynesia. The aim of this first study performed in a tropical area was to assess the seasonal variability of nutrient fluxes and to quantify the contribution of biofouling communities. In situ metabolic enclosure systems were used to measure nutrient uptake or release by ‘cultivation units’ (i.e. 4 pearl oysters with or without associated biofouling). In all 3 study lagoons (Tahiti, Mangareva, Ahe), nutrient fluxes produced by pearl oyster and associated biofouling communities (CR units) were 4- to 6-fold higher than...
Tipo: Text
Palavras-chave: Pearl oysters; Biofouling; Nutrient flux; Aquaculture impact.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00201/31193/29592.pdf

Functional Divergence in Shrimp Anti-Lipopolysaccharide Factors (ALFs): From Recognition of Cell Wall Components to Antimicrobial Activity
Provedor de dados: 5
Autores: Rosa, Rafael Diego; Vergnes, Agnes; De Lorgeril, Julien; Goncalves, Priscila; Perazzolo, Luciane Maria; Saune, Laure; Romestand, Bernard; Fievet, Julie; Gueguen, Yannick; Bachere, Evelyne; Destoumieux-garzon, Delphine.
Antilipopolysaccharide factors (ALFs) have been described as highly cationic polypeptides with a broad spectrum of potent antimicrobial activities. In addition, ALFs have been shown to recognize LPS, a major component of the Gram-negative bacteria cell wall, through conserved amino acid residues exposed in the four-stranded beta-sheet of their three dimensional structure. In penaeid shrimp, ALFs form a diverse family of antimicrobial peptides composed by three main variants, classified as ALF Groups A to C. Here, we identified a novel group of ALFs in shrimp (Group D ALFs), which corresponds to anionic polypeptides in which many residues of the LPS binding site are lacking. Both Group B (cationic) and Group D (anionic) shrimp ALFs were produced in a...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00160/27077/25236.pdf

PenBase, the shrimp antimicrobial peptide penaeidin database: Sequence-based classification and recommended nomenclature
Provedor de dados: 5
Autores: Gueguen, Yannick; Garnier, Julien; Robert, Lorenne; Lefranc, Marie-paule; Mougenot, Isabelle; De Lorgeril, Julien; Janech, Michael; Gross, Paul S.; Warr, Gregory W.; Cuthbertson, Brandon; Barracco, Margherita A.; Bulet, Philippe; Aumelas, Andre&amp;#769;; Yang, Yinshan; Bo, Dong; Xiang, Jianhai; Tassanakajon, Anchalee; Piquemal, Piquemal; Bachere, Evelyne.
Antimicrobial peptides play a major role in innate immunity. The penaeidins, initially characterized from the shrimp Litopenaeus vannamei, are a family of antimicrobial peptides that appear to be expressed in all penaeid shrimps. As of recent, a large number of penaeid nucleotide sequences have been identified from a variety of penaeid shrimp species and these sequences currently reside in several databases under unique identifiers with no nomenclatural continuity. To facilitate research in this field and avoid potential confusion due to a diverse number of nomenclatural designations, we have made a systematic effort to collect, analyse, and classify all the penaeidin sequences available in every database. We have identified a common penaeidin signature...
Tipo: Text
Palavras-chave: Nomenclature; Sequence database; Crustacea; Antimicrobial peptide; Penaeid shrimp; Penaeidin.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2332.pdf

Differential basal expression of immune genes confers Crassostrea gigas resistance to Pacific Oyster Mortality Syndrome
Provedor de dados: 5
Autores: De Lorgeril, Julien; Petton, Bruno; Lucasson, Aude; Perez, Valérie; Stenger, Pierre-louis; Degremont, Lionel; Montagnani, Caroline; Escoubas, Jean Michel; Haffner, Philippe; Allienne, Jean-françois; Leroy, Marc; Lagarde, Franck; Vidal Dupiol, Jeremie; Gueguen, Yannick; Mitta, Guillaume.
Background: As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible). Results: We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein...
Tipo: Text
Palavras-chave: Pacific oyster; Oyster disease; Resistance; OsHV-1; Antiviral molecular pathways; Invertebrate immunity.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00602/71369/69811.pdf

A Sustained Immune Response Supports Long-Term Antiviral Immune Priming in the Pacific Oyster,  Crassostrea gigas
Provedor de dados: 5
Autores: Lafont, Maxime; Vergnes, Agnes; Vidal-dupiol, Jeremie; De Lorgeril, Julien; Gueguen, Yannick; Haffner, Philippe; Petton, Bruno; Chaparro, Cristian; Barrachina, Celia; Destoumieux-garzon, Delphine; Mitta, Guillaume; Gourbal, Benjamin; Montagnani, Caroline.
Over the last decade, innate immune priming has been evidenced in many invertebrate phyla. If mechanistic models have been proposed, molecular studies aiming to substantiate these models have remained scarce. We reveal here the transcriptional signature associated with immune priming in the oyster Crassostrea gigas. Oysters were fully protected against Ostreid herpesvirus 1 (OsHV-1), a major oyster pathogen, after priming with poly(I·C), which mimics viral double-stranded RNA. Global analysis through RNA sequencing of oyster and viral genes after immune priming and viral infection revealed that poly(I·C) induces a strong antiviral response that impairs OsHV-1 replication. Protection is based on a sustained upregulation of immune genes, notably genes...
Tipo: Text
Palavras-chave: Innate immunity; Priming; OsHV-1; Antiviral response; Immune memory; Oyster; POMS; Poly(I·C); Interferon; Transcriptomic.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00614/72580/71541.pdf

Quelles stratégies alternatives aux antibiotiques en aquaculture ?
Provedor de dados: 5
Autores: Nicolas, Jean-louis; Gatesoupe, Joel; Frouel, Stephane; Bachere, Evelyne; Gueguen, Yannick.
Tipo: Text
Ano: 2007
URL: http://archimer.ifremer.fr/doc/00066/17704/15222.pdf

Maîtrise technique de la production de poissons lagonaires Rapport 2008 et annexes
Provedor de dados: 5
Autores: Maamaatuaiahutapu, Moana; Joufoques, Vaiana; Tamata, Thiery; Dupieux, Sylvain; Teissier, Alexandre; Rarahu, David; Remoissenet, Georges; Gasset, Eric; Knockaert, Camille; Gueguen, Yannick; Coves, Denis.
Ce rapport traite de la poursuite de l’acquisition de connaissances, du début du transfert vers le secteur privé et des futurs travaux sur de l’élevage du Paraha peue (Platax orbicularis).   Acquisition de connaissances porte sur (i) Grossissement en cages en fonction du site d’élevage, tests de produits immuno-stimulants, définition de traitements anti-parasitaires, mise au point des méthodes de transport d’alevins et la mise en cages précoces d’animaux de 1 g pour le transport par voie aérienne vers les îles (i.i.) Synchronisation des pontes et mise en place d’un plan de croisement de géniteurs diminuant le risque de consanguinité et permettant un progrès génétique par la domestication et/ou la sélection, ainsi que la mise au point d’outils de...
Tipo: Text
Ano: 2008
URL: http://archimer.ifremer.fr/doc/00128/23887/21820.pdf

Replication factor C from the hyperthermophilic archaeon Pyrococcus abyssi does not need ATP hydrolysis for clamp-loading and contains a functionally conserved RFC PCNA-binding domain
Provedor de dados: 5
Autores: Henneke, Ghislaine; Gueguen, Yannick; Flament, Didier; Azam, Philippe; Querellou, Joel; Dietrich, Jacques; Hubscher, Ulrich; Raffin, Jean-paul.
The molecular organization of the replication complex in archaea is similar to that in eukaryotes. Only two proteins homologous to subunits of eukaryotic replication factor C (RFC) have been detected in Pyrococcus abyssi (Pab). The genes encoding these two proteins are arranged in tandem. We cloned these two genes and co-expressed the corresponding recombinant proteins in Escherichia coli. Two inteins present in the gene encoding the small subunit (Pab RFC-small) were removed during cloning. The recombinant protein complex was purified by anion-exchange and hydroxyapatite chromatography. Also, the Pab RFC-small subunit could be purified, while the large subunit (Pab RFC-large) alone was completely insoluble. The highly purified Pab RFC complex possessed an...
Tipo: Text
Palavras-chave: PCNA binding domain; Pyrococcus abyssi; Hyperthermophile; Archaea; Replication factor C.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/2002/publication-675.pdf

Integrated management of pearl culture in French Polynesia in the context of global change: Synopsis of existing results
Provedor de dados: 5
Autores: Gueguen, Yannick; Gaertner-mazouni, Nabila; Lo, Cedrik; Le Moullac, Gilles.
The paper presents a state of the art on knowledge of the black pearl oyster aquaculture at the scale of French Polynesia. It also introduces the main results obtained throughout the multi-partners POLYPERL project. The goal of this project was to develop an integrated and participative action-research of the pearl oyster culture system, focusing on the environmental, technological, economical and societal dimensions impacting the industry. The research proposed ranges from the understanding of biological phenomena of the production system to socio-economic aspects and governance of the industry, taking into account the management of anthropogenic, climate and health risks. We introduce here the different papers from the POLYPERL project that are compiled...
Tipo: Text
Palavras-chave: Pearl culture; Global change; French Polynesia; Pinctada margaritifera.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00346/45698/45320.pdf

Contribution of Viral Genomic Diversity to Oyster Susceptibility in the Pacific Oyster Mortality Syndrome
Provedor de dados: 5
Autores: Delmotte, Jean; Chaparro, Cristian; Galinier, Richard; De Lorgeril, Julien; Petton, Bruno; Stenger, Pierre-louis; Vidal-dupiol, Jeremie; Destoumieux-garzon, Delphine; Gueguen, Yannick; Montagnani, Caroline; Escoubas, Jean Michel; Mitta, Guillaume.
Juvenile Pacific oysters (Crassostrea gigas) are subjected to recurrent episodes of mass mortalities that constitute a threat for the oyster industry. This mortality syndrome named “Pacific Oyster Mortality Syndrome” (POMS) is a polymicrobial disease whose pathogenesis is initiated by a primary infection by a variant of an Ostreid herpes virus named OsHV-1 μVar. The characterization of the OsHV-1 genome during different disease outbreaks occurring in different geographic areas has revealed the existence of a genomic diversity for OsHV-1 μVar. However, the biological significance of this diversity is still poorly understood. To go further in understanding the consequences of OsHV-1 diversity on POMS, we challenged five biparental families of oysters to two...
Tipo: Text
Palavras-chave: Crassostrea gigas; Herpesvirus diversity; Genotype-genotype interactions; Oyster genetic background; Viral populations.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00643/75533/76414.pdf

Biofouling development and its effect on growth and reproduction of the farmed pearl oyster Pinctada margaritifera
Provedor de dados: 5
Autores: Lacoste, Elise; Le Moullac, Gilles; Levy, Peva; Gueguen, Yannick; Gaertner-mazouni, Nabila.
In bivalve aquaculture, dominant fouling organisms are filter feeders which can compete for food with reared bivalves, sometimes causing mortality or reducing their growth rate. This study investigated the effect of biofouling on the farmed pearl oyster Pinctada margaritifera in two lagoons of French Polynesia. Survival, growth and reproduction of 2 year-old pearl oysters were monitored with regular sampling schedules, from the initial stage of colonization up to 20 months of biofouling accumulation. Control groups of pearl oysters were kept free of biofouling as is the current practice in pearl farms. After more than a year of monitoring, no significant difference was recorded in shell growth rate between pearl oysters reared with epibionts and the...
Tipo: Text
Palavras-chave: Pearl oyster culture; Pinctada margaritifera; Biofouling; Growth; Reproduction.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00201/31188/29587.pdf

Use of Natural Antimicrobial Peptides and Bacterial Biopolymers for Cultured Pearl Production
Provedor de dados: 5
Autores: Simon-colin, Christelle; Gueguen, Yannick; Bachere, Evelyne; Kouzayha, Achraf; Saulnier, Denis; Gayet, Nicolas; Guezennec, Jean.
Cultured pearls are the product of grafting and rearing of Pinctada margaritifera pearl oysters in their natural environment. Nucleus rejections and oyster mortality appear to result from bacterial infections or from an inappropriate grafting practice. To reduce the impact of bacterial infections, synthetic antibiotics have been applied during the grafting practice. However, the use of such antibiotics presents a number of problems associated with their incomplete biodegradability, limited efficacy in some cases, and an increased risk of selecting for antimicrobial resistant bacteria. We investigated the application of a marine antimicrobial peptide, tachyplesin, which is present in the Japanese horseshoe crab Tachypleus tridentatus, in combination with...
Tipo: Text
Palavras-chave: Pearl oyster; Exopolysaccharide; Tachyplesin; Antimicrobial.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00275/38599/37128.pdf

Molecular characterization of penaeidins from two Atlantic Brazilian shrimp species, Farfantepenaeus paulensis and Litopenaeus schmitti
Provedor de dados: 5
Autores: Barracco, Margherita; De Lorgeril, Julien; Gueguen, Yannick; Bachere, Evelyne.
We report here the molecular cloning of new members of the penaeidin family from two Atlantic penaeids from Brazil, Litopenaeus schmitti and Farfantepenaeus paulensis. The presence of penaeidins in the granular hemocytes of both shrimps was first evidenced by immunofluorescence, using polyclonal antibodies raised against L. vannamei penaeidin Litvan PEN3-1. cDNAs from the hemocytes of both Brazilian species were obtained by reverse transcription and the sequences encoding penaeidins were amplified by PCR, using primers based on penaeidin consensus sequences. Five penaeidin clones were obtained. According to the international penaeidin classification (PenBase, http://www.penbase.immunaqua.com), the deduced amino acid sequences of two clones from L. schmitti...
Tipo: Text
Palavras-chave: Immuno detection; Molecular cloning; Litopenaeus schmitti; Farfantepenaeus paulensis; Brazilian penaeid shrimps; Hemocytes; Antimicrobial peptides; Penaeidins.
Ano: 2005
URL: http://archimer.ifremer.fr/doc/2005/publication-3582.pdf

Effect of electrolysis treatment on the biomineralization capacities of pearl oyster Pinctada margaritifera juveniles
Provedor de dados: 5
Autores: Latchere, Oihana; Fievet, Julie; Lo, Cedrik; Schneider, Denis; Dieu, Stephanie; Cabral, Philippe; Belliard, Corinne; Ky, Chin-long; Gueguen, Yannick; Saulnier, Denis.
The present study investigated the effect of electrolysis on the biomineralization capacities of juveniles of the mollusk Pinctada margaritifera for the first time. Size-selected individuals from two groups, “Medium” and “Large”, from a multi-parental family produced in a hatchery system were subjected to electrolysis under a low voltage current over a nine-week experimental period. The growth of the juveniles was individually monitored and assessed weekly by wet weight and shell height measurements. At the end of the experiment, mantle tissue was sampled for biomineralization-related gene expression analysis. Electrolysis significantly increased pearl oyster growth in terms of shell height and wet weight for Large juveniles from the 5th and the 2nd week,...
Tipo: Text
Palavras-chave: Pearl oyster; Pinctada margaritifera; Electrolysis; Biomineralization; Gene expression.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00343/45410/44924.pdf

Rapid accumulation of an interleukin 17 homolog transcript in Crassostrea gigas hemocytes following bacterial exposure
Provedor de dados: 5
Autores: Roberts, S; Gueguen, Yannick; De Lorgeril, Julien; Goetz, F.
Interleukin-17 (IL-17) gene models have been found in the sequenced genomes of Strongylocentrotus purpuratus and Caenorhabditis elegans. However, there have been no published reports on the empirical cloning and characterization of any interleukin cDNAs in invertebrates. From a Pacific oyster (Crossostrea gigas) hemocyte cDNA library, two clones were obtained that encoded a protein similar to vertebrate IL-17s. The putative oyster IL-17 homolog (CgIL-17) was 27% identical to rainbow trout IL-17D, 21% to human IL-17D and 24% to an IL-17D-like gene model obtained from the annotation of the sea urchin genome. IL-17s from the oyster, sea urchin, trout and human, contained conserved cysteine residues found in all forms of IL-17 in mammals. Injection of bacteria...
Tipo: Text
Palavras-chave: Invertebrate innate immunity; Crassostrea gigas; Invertebrate cytokines; Hemocytes; Pacific oyster; Interleukin.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-4151.pdf

Characterization of a highly thermostable alkaline phosphatase from the euryarchaeon Pyrococcus abyssi
Provedor de dados: 5
Autores: 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

Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers
Provedor de dados: 5
Autores: Gueguen, Yannick; Saulnier, Denis; Santini, Adrien; Magre, Kevin; Garen, Pierre; Bernagout, Solene; Nohl, Marine; Bouisset, Patrick; Helme, Herehia; Planes, Serge; Le Moullac, Gilles.
This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM,...
Tipo: Text
Palavras-chave: Pinctada margaritifera; French Polynesia; Cadmium; Chromium; Gene expression; Metallothionein.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00376/48707/49146.pdf

Oyster hemolymph is a complex and dynamic ecosystem hosting bacteria, protists and viruses
Provedor de dados: 5
Autores: Dupont, Samuel; Lokmer, A.; Corre, E.; Auguet, Jean-christophe; Petton, Bruno; Toulza, E.; Montagnani, Caroline; Tanguy, G.; Pecqueur, D.; Salmeron, C.; Guillou, L.; Desnues, C.; La Scola, B.; Bou Khalil, J.; De Lorgeril, Julien; Mitta, Guillaume; Gueguen, Yannick; Escoubas, Jean Michel.
Background The impact of the microbiota on host fitness has so far mainly been demonstrated for the bacterial microbiome. We know much less about host-associated protist and viral communities, largely due to technical issues. However, all microorganisms within a microbiome potentially interact with each other as well as with the host and the environment, therefore likely affecting the host health. Results We set out to explore how environmental and host factors shape the composition and diversity of bacterial, protist and viral microbial communities in the Pacific oyster hemolymph, both in health and disease. To do so, five oyster families differing in susceptibility to the Pacific oyster mortality syndrome were reared in hatchery and transplanted into a...
Tipo: Text
Palavras-chave: Oyster genetic background; Hemolymph microbiota dynamics; Early-life microbiota; Trans-kingdom interactions; Crassostrea gigas; Within-host ecosystem.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00627/73916/73254.pdf

Impact of pCO2 on the energy, reproduction and growth of the shell of the pearl oyster Pinctada margaritifera
Provedor de dados: 5
Autores: Le Moullac, Gilles; Soyez, Claude; Vidal-dupiol, Jeremie; Belliard, Corinne; Fievet, Julie; Sham-koua, Manaarii; Lo-yat, Alain; Saulnier, Denis; Gaertner-mazouni, N.; Gueguen, Yannick.
The possible consequences of acidification on pearl farming are disruption of oyster metabolism and change in growth. In the laboratory, we studied the impact of pCO2 (3540, 1338 and 541μatm) on the physiology of pearl oysters exposed for 100 days. This experiment was repeated after an interval of one year. Several physiological compartments were examined in pearl oysters: the scope for growth by measuring ingestion, assimilation and oxygen consumption, gametogenesis by means of histological observations, shell growth by measurement and observation by optical and electronic microscopy, and at molecular level by measuring the expression of nine genes of mantle cells implied in the biomineralisation process. Results from both experiments showed that high...
Tipo: Text
Palavras-chave: Global change; Pearl oyster; Bioenergetic; Biomineralization; Pacific Ocean; French Polynesia.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00321/43189/42737.pdf

Inefficient immune response is associated with microbial permissiveness in juvenile oysters affected by mass mortalities on field
Provedor de dados: 5
Autores: De Lorgeril, Julien; Escoubas, Jean Michel; Loubiere, Vincent; Pernet, Fabrice; Le Gall, Patrik; Vergnes, Agnes; Aujoulat, Fabien; Jeannot, Jean-luc; Jumas-bilak, Estelle; Got, Patrice; Gueguen, Yannick; Destoumieux-garzon, Delphine; Bachere, Evelyne.
Since 2008, juvenile Crassostrea gigas oysters have suffered from massive mortalities in European farming areas. This disease of complex etiology is still incompletely understood. Triggered by an elevated seawater temperature, it has been associated to infections by a herpes virus named OsHV-1 as well as pathogenic vibrios of the Splendidus clade. Ruling out the complexity of the disease, most of our current knowledge has been acquired in controlled experiments. Among the many unsolved questions, it is still ignored what role immunity plays in the capacity oysters have to survive an infectious episode. Here we show that juvenile oysters susceptible to the disease mount an inefficient immune response associated with microbial permissiveness and death. We...
Tipo: Text
Palavras-chave: Host pathogen interaction; Innate immunity; Invertebrate; Mollusk; In situ mortality; Total bacteria; Crassostrea gigas.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00433/54470/55845.pdf

Development of in situ hybridisation using 16S rRNA gene to monitor black-lip pearl oyster, Pinctada margaritifera, larvae in plankton samples
Provedor de dados: 5
Autores: Thomas, Yoann; Belliard, Corinne; Garen, Pierre; Gueguen, Yannick; Montagnani, Caroline.
In French Polynesia, the black-lip pearl oyster Pinctada margaritifera has been farmed to produce pearls since the 1980s, forming the basis of a major industry. The sustainability of this activity relies on spat collection in the lagoons. However, pearl oyster spat can be difficult to identify for the evaluation of stock variations. It is especially hard to distinguish Pinctada spp. larvae at a very early stage of development. In the present study, a whole- mount in situ hybridisation (ISH) technique was developed to allow the discrimination of larvae of closely-related pearl oyster species found in the French Polynesian atolls. Using specific ribosomal 16S-DNA sequence data, we were able to successfully differentiate between Pinctada margaritifera and...
Tipo: Text
Palavras-chave: Whole larvae in situ hybridisation; 16S rRNA; Plankton; Species identification; Pearl oyster; Pinctada margaritifera.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00035/14603/11923.pdf

An updated assessment of     Symbiodinium     spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B
Provedor de dados: 5
Autores: Rouze, Heloise; Lecellier, Gael J.; Saulnier, Denis; Planes, Serge; Gueguen, Yannick; Wirshing, Herman H.; Berteaux-lecellier, Veronique.
The adaptative bleaching hypothesis (ABH) states that, depending on the symbiotic flexibility of coral hosts (i.e., the ability of corals to “switch” or “shuffle” their algal symbionts), coral bleaching can lead to a change in the composition of their associated Symbiodinium community and, thus, contribute to the coral’s overall survival. In order to determine the flexibility of corals, molecular tools are required to provide accurate species delineations and to detect low levels of coral-associated Symbiodinium. Here, we used highly sensitive quantitative (real-time) PCR (qPCR) technology to analyse five common coral species from Moorea (French Polynesia), previously screened using only traditional molecular methods, to assess the presence of...
Tipo: Text
Palavras-chave: Corals; French polynesia; Clade B; Symbiodinium; QPCR; Flexibility; Generalist; Faithful clade.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00365/47652/47683.pdf

Biofloc technology applied to rear shrimp Litopenaeus Stylirostris broodstock: An integrated and development research project in New Caledonia and French Polynesia
Provedor de dados: 5
Autores: Chim, Liet; Cardona, Emilie; Lorgeoux, Benedicte; Gueguen, Yannick; Saulnier, Denis; Goguenheim, Jean; Wantiez, Laurent; Cahu, Chantal.
Shrimp farming in New-Caledonia faces up to difficulties. A fluctuating quality of broodstock prevents sustainable production of larvae in quantity and quality. The traditional extensive rearing method of broodstock in outdoor earthen ponds used in New Caledonia raises several issues: poor water quality control and biosecurity. Therefore it is fundamental to modify the broodstock culture strategy in order to achieve an easier water quality management and maximal biosecurity. Biofloc technology (BFT) offers easier water quality management, higher natural productivity, higher level of biosecurity, and could be a good alternative. Since 2011 a R&amp;D program started under the supervision of IFREMER in New Caledonia and French Polynesia in order to study and...
Tipo: Text
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00250/36084/34635.pdf

Molecular diversity of antimicrobial effectors in the oyster Crassostrea gigas
Provedor de dados: 5
Autores: Schmitt, Paulina; Gueguen, Yannick; Desmarais, Erick; Bachere, Evelyne; De Lorgeril, Julien.
Background: To gain insight into the molecular diversity of antimicrobial peptides and proteins in the oyster Crassostrea gigas, we characterized and compared the sequence polymorphism of the antimicrobial peptides (AMPs), Cg-Defensins (Cg-Defs) and Cg-Proline Rich peptide (Cg-Prp), and of the bactericidal permeability increasing protein, Cg-BPI. For that, we analyzed genomic and transcript sequences obtained by specific PCR amplification and in silico searches. Results: High diversification among the three antimicrobial effectors was evidenced by this polymorphism survey. On the basis of sequence phylogenies, each AMP aggregates into clearly defined groups of variants and is the product of a multigenic family displaying a variety of gene structures. In...
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00001/11182/6691.pdf

Different secretory repertoires control the biomineralization processes of prism and nacre deposition of the pearl oyster shell
Provedor de dados: 5
Autores: Marie, Benjamin; Joubert, Caroline; Tayale, Alexandre; Zanella-cleon, Isabelle; Belliard, Corinne; Piquemal, David; Cochennec-laureau, Nathalie; Marin, Frederic; Gueguen, Yannick; Montagnani, Caroline.
Mollusca evolutionary success can be attributed partly to their efficiency to sustain and protect their soft body with an external biomineralized structure, the shell. Current knowledge of the protein set responsible for the formation of the shell microstructural polymorphism and unique properties remains largely patchy. In Pinctada margaritifera and Pinctada maxima, we identified 80 shell matrix proteins, among which 66 are entirely unique. This is the only description of the whole "biomineralization toolkit" of the matrices that, at least in part, is thought to regulate the formation of the prismatic and nacreous shell layers in the pearl oysters. We unambiguously demonstrate that prisms and nacre are assembled from very different protein repertoires....
Tipo: Text
Palavras-chave: Mantle; Mollusk shell matrix proteins; Proteome; Transcriptome; Evolution.
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00118/22959/20922.pdf