Effect of Anaerobiosis on Expression of Virulence Factors in Vibrio cholerae
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
Effect of Anaerobiosis on Expression of Virulence Factors in
Vibrio cholerae
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| Creator |
Krishnan, H. H
Ghosh, Amalendu Paul, Kalidas Chowdhury, Rukhsana |
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| Subject |
Infectious Diseases and Immunology
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| Description |
In Vibrio cholerae, the transmembrane DNA binding proteins, ToxR and TcpP, activate expression of the
regulatory gene toxT in response to specific environmental signals. The resulting enhanced level of ToxT leads
to a coordinated increase in the production of a subset of virulence factors, including cholera toxin (CT) and
toxin-coregulated pilus (TCP). The effect of anaerobiosis on expression of the V. cholerae virulence regulatory
cascade was examined. The expression of the major regulatory genes, tcpP, toxR, and toxT, in anaerobically
grown V. cholerae was comparable to that in cells grown under aerobic conditions, and no significant difference
in the ToxT-dependent expression of tcpA was detected when aerobic and anaerobic cultures were compared.
However, in spite of the presence of functional ToxT, ctxAB expression was drastically reduced, and practically
no CT was detected in cells grown under anaerobic conditions. In a V. cholerae hns mutant, however, high levels
of ctxAB expression occurred even under anaerobic conditions. Also, deletion of the H-NS binding site from the
ctxAB promoter eliminated anaerobic repression of ctxAB expression. These results suggest that H-NS directly
represses ctxAB expression under anaerobic growth conditions. It has been reported that in the first stage of
infection of infant mice by V. cholerae, tcpA is expressed but ctxAB expression is shut off (S. H. Lee, D. L. Hava,
M. K. Waldor, and A. Camilli, Cell 99: 625-634, 1999). This pattern is similar to the pattern in anaerobic
cultures of V. cholerae. Under all other in vitro conditions, ctxAB and tcpA are known to be coordinately
expressed.
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| Publisher |
American Society for Microbiology
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| Date |
2004
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/526/1/INFECTION_AND_IMMUNITY%2C_72(_7)%2C__3961%2D3967_[48].pdf
Krishnan, H. H and Ghosh, Amalendu and Paul, Kalidas and Chowdhury, Rukhsana (2004) Effect of Anaerobiosis on Expression of Virulence Factors in Vibrio cholerae. Infection and Immunity, 72 (7). pp. 3961-3967. |
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| Relation |
http://dx.doi.org/10.1128/IAI.72.7.3961–3967.2004
http://www.eprints.iicb.res.in/526/ |
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