This Article Full Text (PDF) Other Versions of this Article: IAI.01435-06v1 75/4/1946    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chatterjee, A. Articles by Chowdhury, R. Search for Related Content PubMed PubMed Citation Articles by Chatterjee, A. Articles by Chowdhury, R.

 Previous Article  |  Next Article 

Infect. Immun. doi:10.1128/IAI.01435-06
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

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

Biophysics Division and Medicinal Chemistry Division; Indian Institute of Chemical Biology, Calcutta 700 032, India

^* To whom correspondence should be addressed. Email: rukhsana{at}iicb.res.in.

	Abstract

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 NMR, GC and GC-MS analyses. The unsaturated fatty acids detected in bile, arachidonic, linoleic and oleic, drastically repressed expression of the ctxAB and tcpA genes, encoding cholera toxin and the major subunit of the toxin co-regulated 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 non-functional 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 a H-NS and ToxR/ToxT independent manner.

This article has been cited by other articles:

• Bina, X. R., Provenzano, D., Nguyen, N., Bina, J. E. (2008). Vibrio cholerae RND Family Efflux Systems Are Required for Antimicrobial Resistance, Optimal Virulence Factor Production, and Colonization of the Infant Mouse Small Intestine. Infect. Immun. 76: 3595-3605 [Abstract] [Full Text]  
• Chatterjee, A., Chowdhury, R. (2008). Bile and Unsaturated Fatty Acids Inhibit the Binding of Cholera Toxin and Escherichia coli Heat-Labile Enterotoxin to GM1 Receptor. Antimicrob. Agents Chemother. 52: 220-224 [Abstract] [Full Text]