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| Costa, S.C.P.; Ribeiro, C.; Girard, P.A.; Zumbihl, R.; Brehélin, M.. |
| Haemocytes are the main immunocompetent cells in insect cellular immune reactions. Here, we show that in Spodoptera littoralis, granular haemocytes are the primary phagocyte haemocytes, both in vivo and in vitro. The "trigger" and "zipper" modes of engulfment known in mammal macrophages are active, in vivo, in S. littoralis granular haemocytes, together with macropinocytosis. Lipopolysaccharide as well as lipoteichoic acid inhibit the binding of both Gram-positive (Corynebacterium xerosis) and Gramnegative (Escherichia coli) bacteria on granular haemocytes. In addition, different ligands can inhibit the binding of E coli. Most of these inhibitors are known as ligands of scavenger receptors in mammal macrophages and we hypothesise that one of the receptors... |
| Tipo: Journal Article |
Palavras-chave: SPODOPTERA LITTORALIS; NOCTUELLE MACROPINOCYTOSIS; TRIGGER; ZIPPER; RECEPTOR; INSECT. |
| Ano: 2005 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD201069bfa10d&uri=/notices/prodinra1/2011/05/ |
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| Brugirard-Ricaud, K.; Duchaud, E.; Givaudan, A.; Girard, P.A.; Kunst, F.; Boemare, N.; Brehélin, M.; Zumbihl, R.. |
| Photorhabdus is an entomopathogenic bacterium belonging to the Enterobacteriaceae. The genome of the TT01 strain of Photorhabdus luminescens was recently sequenced and a large number of toxin-encoding genes were found. Genomic analysis predicted the presence on the chromosome of genes encoding a type three secretion system (TTSS), the main role of which is the delivery of effector proteins directly into eukaryotic host cells. We report here the functional characterization of the TTSS. The locus identified encodes the secretion/translocation apparatus, gene expression regulators and an effector protein - LopT - homologous to the Yersinia cysteine protease cytotoxin YopT. Heterologous expression in Yersinia demonstrated that LopT was translocated into mammal... |
| Tipo: Journal Article |
Palavras-chave: ENTOMOPATHOGENIC BACTERIUM; GENE EXPRESSION; ENTOMOPATHOGENIC NEMATODE; INSECT CELL MEMBRANE. |
| Ano: 2005 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD2008e8fb85eb&uri=/notices/prodinra1/2009/03/ |
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| Destoumieux-Garzon, D.; Brehélin, M.; Bulet, B.; Boublik, Y.; Girard, P.A.; Baghdiguian, S.; Zumbihl, R.; Escoubas, J.M.. |
| Background: X-tox proteins are a family of immune-related proteins only found in Lepidoptera and characterized by imperfectly conserved tandem repeats of several defensin-like motifs. Previous phylogenetic analysis of X-tox genes supported the hypothesis that X-tox have evolved from defensins in a lineage-specific gene evolution restricted to Lepidoptera. In this paper, we performed a protein study in which we asked whether X-tox proteins have conserved the antimicrobial functions of their ancestral defensins and have evolved as defensin reservoirs.Methodology/Principal Findings: We followed the outcome of Spod-11-tox, an X-tox protein characterized in Spodoptera frugiperda, in bacteria-challenged larvae using both immunochemistry and antimicrobial assays.... |
| Tipo: Journal Article |
Palavras-chave: LEPIDOPTERE X-TOX PROTEIN; LEPIDOPTERA; IMMUNE-RELATED PROTEIN; ANCESTRAL DEFENSINS; SPODOPTERA FRUGIPERDA. |
| Ano: 2009 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD201095cf8004&uri=/notices/prodinra1/2010/10/ |
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| Costa, S.C.P.; Girard, P.A.; Brehélin, M.; Zumbihl, R.. |
| Photorhabdus species are gram-negative entomopathogenic bacteria of the family Enterobacteriaceae. Among the different members of the genus, one species, Photorhabdus asymbiotica, is a pathogen of both insects and humans. The pathogenicity mechanisms of this bacterium are unknown. Here we show that P. asymbiotica is a facultative intracellular pathogen that is able to replicate inside human macrophage-like cells. Furthermore, P. asymbiotica was shown for the first time in an intracellular location after insect infection. We also demonstrated that among Australian and American clinical isolates, only the Australian strains were able to invade nonphagocytic human cells. In cell culture infection experiments, Australian clinical isolates as well as cell-free... |
| Tipo: Journal Article |
Palavras-chave: PHOTORHABDUS; MACROPHAGE-LIKE CELL; PATHOGENICITY MECHANISM; CELL CULTURE; PATHOGEN INSECT; PATHOGEN HUMAN. |
| Ano: 2009 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD2010d0f9e94c&uri=/notices/prodinra1/2010/10/ |
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| Vigneux, F.; Zumbihl, R.; Jubelin, G.; Ribeiro, C.; Poncet, J.; Baghdiguian, S.; Givaudan, A.; Brehélin, M.. |
| Xenorhabdus nematophila, a member of the Enterobacteriaceae, kills many species of insects by strongly depressing the immune system and colonizing the entire body. A peptide cytotoxin has been purified from X. nematophila broth growth, and the cytolytic effect on insect immunocytes and hemolytic effect on mammalian red blood cells of this toxin have been described (Ribeiro, C., Vignes, M., and Brehelin, M. (2003) J. Mal. Chem. 278, 3030-3039). We show here that this toxin, Xenorhabdus alpha-xenorhabdolysin (Xax), triggers apoptosis in both insect and mammalian cells. We also report the cloning and sequencing of two genes, xaxAB, encoding this toxin in X. nematophila. The expression of both genes in recombinant Escherichia coli led to the production of... |
| Tipo: Journal Article |
Palavras-chave: IMMUNE SYSTEM; ENTOMOPATHOGENIC BACTERIA; CYTOTOXIN. |
| Ano: 2007 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PROD2008d7f6e01&uri=/notices/prodinra1/2010/11/ |
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