Consulta: subjectFacets:"Defensin"
Registros recuperados: 8
Data/hora: 02/06/2024 01:18:11

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

The new insights into the oyster antimicrobial defense: Cellular, molecular and genetic view
Provedor de dados: 5
Autores: 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

Differential distribution and defence involvement of antimicrobial peptides in mussel
Provedor de dados: 5
Autores: 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

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

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

Resistance to Antimicrobial Peptides in Vibrios
Provedor de dados: 5
Autores: Destoumieux-garzón, Delphine; Duperthuy, Marylise; Vanhove, Audrey; Schmitt, Paulina; Wai, Sun.
Vibrios are associated with a broad diversity of hosts that produce antimicrobial peptides (AMPs) as part of their defense against microbial infections. In particular, vibrios colonize epithelia, which function as protective barriers and express AMPs as a first line of chemical defense against pathogens. Recent studies have shown they can also colonize phagocytes, key components of the animal immune system. Phagocytes infiltrate infected tissues and use AMPs to kill the phagocytosed microorganisms intracellularly, or deliver their antimicrobial content extracellularly to circumvent tissue infection. We review here the mechanisms by which vibrios have evolved the capacity to evade or resist the potent antimicrobial defenses of the immune cells or tissues...
Tipo: Text
Palavras-chave: Vibrio; Lipopolysaccharide; Outer membrane vesicle; Membrane transporter; Innate immunity; Defensin; Cathelicidin; Bactericidal/permeability-increasing protein.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00276/38767/37308.pdf

An intimate link between antimicrobial peptide sequence diversity and binding to essential components of bacterial membranes
Provedor de dados: 5
Autores: Schmitt, Paulina; Rosa, Rafael D.; Destoumieux-garzon, Delphine.
Antimicrobial peptides and proteins (AMPs) are widespread in the living kingdom. They are key effectors of defense reactions and mediators of competitions between organisms. They are often cationic and amphiphilic, which favors their interactions with the anionic membranes of microorganisms. Several AMP families do not directly alter membrane integrity but rather target conserved components of the bacterial membranes in a process that provides them with potent and specific antimicrobial activities. Thus, lipopolysaccharides (LPS), lipoteichoic acids (LTA) or the peptidoglycan precursor Lipid II are targeted by a broad series of AMPs. Studying the functional diversity of immune effectors tells us about the essential residues involved in AMP mechanism of...
Tipo: Text
Palavras-chave: Functional diversity; Defensin; Anti-lipopolysaccharide factor; Mechanism of action; Resistance.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00286/39710/38165.pdf

Influence of temperature, salinity and E. coli tissue content on immune gene expression in mussel: Results from a 2005-2008 survey
Provedor de dados: 5
Autores: 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