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| 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 |
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| Mitta, Guillaume; Vandenbulcke, Franck; Noel, Thierry; Romestand, Bernard; Beauvillain, Jean Claude; Salzet, Michel; Roch, Philippe. |
| In previous papers, we characterised 3 types of 4-kDa, cysteine-rich, cationic antimicrobial peptides: MGDs (for Mytilus galloprovincialis defensins), mytilins and myticins, which are abundant in the mussel hemocytes. In the present work, me revealed a differential distribution of the cells expressing the different genes. In addition, using confocal and electron microscopy, we confirmed that defensins and mytilins were partially located in different sub-types of circulating hemocytes although the peptides can be located in the same cell, and even in the same granule. We also demonstrated that mytilins exert their microbicidal effect within the cells through the process of phagosome-mytilin granule fusion leading to the co-location of ingested bacteria and... |
| Tipo: Text |
Palavras-chave: Innate immunity; Hemocyte; Mussel; Myticin; Mytilin; Defensin; Antimicrobial. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-413.pdf |
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| Li, Hui; Toubiana, Mylene; Monfort, Patrick; Roch, Philippe. |
| Several bivalves, including mussels, suffered from mortalities particularly in summer. To look for the possible effect of environmental parameters on immune capacities, Mytilus galloprovincialis were collected monthly from August 2005 to July 2008 from the Palavas Laguna, French Mediterranean coast. Q-PCR was used to quantify the expression of three antimicrobial peptide genes (defensin, mytilin B and myticin B), in addition to lysozyme and HSP70. House keeping gene was 28S rRNA. Defensin, myticin B and lysozyme appeared more expressed in spring-summer than in winter. In contrast, HSP70 expression was higher in winter. Statistical studies using principal component analysis (PCA) and multiple regression models revealed positive influence of temperature on... |
| Tipo: Text |
Palavras-chave: Mollusks; Mytilus; Innate immunity; Seasonal variations; Immune survey; Q PCR; HSP70; Lysozyme; Myticin; Mytilin; Defensin; Antimicrobial peptide. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7345.pdf |
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| Bachere, Evelyne; Rosa, Rafael Diego; Schmitt, Paulina; Poirier, Aurore; Merou, Nicolas; Charriere, Guillaume; Destoumieux-garzon, Delphine. |
| Oysters are sessile filter feeders that live in close association with abundant and diverse communities of microorganisms that form the oyster microbiota. In such an association, cellular and molecular mechanisms have evolved to maintain oyster homeostasis upon stressful conditions including infection and changing environments. We give here cellular and molecular insights into the Crassostrea gigas antimicrobial defense system with focus on antimicrobial peptides and proteins (AMPs). This review highlights the central role of the hemocytes in the modulation and control of oyster antimicrobial response. As vehicles for AMPs and other antimicrobial effectors, including reactive oxygen species (ROS), and together with epithelia, hemocytes provide the oyster... |
| Tipo: Text |
Palavras-chave: Mollusk; Immunity; Antimicrobial peptide; Hemocyte; Defensin. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36552/35097.pdf |
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