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Effect of fatty acids and cholesterol present in bile on expression of virulence factors and motility of Vibrio cholerae

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Title Effect of fatty acids and cholesterol present in bile on expression of virulence factors and motility of Vibrio cholerae
 
Creator Chatterjee, A
Dutta, PK
Chowdhury, R
 
Subject Immunology; Infectious Diseases
 
Description Bile induces pleiotropic responses that affect production of virulence factors, motility, and other phenotypes in the enteric pathogen Vibrio cholerae. Since bile is a heterogeneous mixture, crude bile was fractionated, and the components that mediate virulence gene repression and enhancement of motility were identified by nuclear magnetic resonance, gas chromatography (GC), and GC-mass spectrometry analyses. The unsaturated fatty acids detected in bile, arachidonic, linoleic, and oleic acids, drastically repressed expression of the ctxAB and tcpA genes, which encode cholera toxin and the major subunit of the toxin-coregulated pilus, respectively. The unsaturated fatty acid-dependent repression was due to silencing of ctxAB and tcpA expression by the histone-like nucleoid-structuring protein H-NS, even in the presence of the transcriptional activator ToxT. Unsaturated fatty acids also enhanced motility of V. cholerae due to increased expression of flrA, the first gene of a regulatory cascade that controls motility. H-NS had no role in the fatty acid-mediated enhancement of motility. It is likely that the ToxR/ToxT system that negatively regulates motility is rendered nonfunctional in the presence of unsaturated fatty acids, leading to an increase in motility. Motility and flrA expression were also increased in the presence of cholesterol, another component of bile, in an H-NS- and ToxR/ToxT-independent manner.
 
Publisher AMER SOC MICROBIOLOGYWASHINGTON1752 N ST NW, WASHINGTON, DC 20036-2904 USA
 
Date 2011-09-20T12:12:38Z
2011-09-20T12:12:38Z
2007
 
Type Article
 
Identifier INFECTION AND IMMUNITY
0019-9567
http://hdl.handle.net/123456789/14354
 
Language English