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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, Arpita
Dutta, Pradeep K
Chowdhury, Rukhsana
 
Subject Infectious Diseases and Immunology
 
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 histonelike
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.
 
Date 2007
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/356/1/INFECTION_AND_IMMUNITY%2C_75%2C(_4)%2C_1946%2D1953[97].pdf
Chatterjee, Arpita and Dutta, Pradeep K and Chowdhury, Rukhsana (2007) Effect of Fatty Acids and Cholesterol Present in Bile on Expression of Virulence Factors and Motility of Vibrio cholerae. Infection and Immunity, 75 (4). pp. 1946-1953.
 
Relation http://dx.doi.org/10.1128/IAI.01435-06
http://www.eprints.iicb.res.in/356/