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Genetic organization of pre-CTX and CTXn prophages in the genome of an environmental Vibrio cholerae non-O1, non-O139 strain

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Title Genetic organization of pre-CTX and CTXn prophages in the genome of an environmental Vibrio cholerae non-O1, non-O139 strain
 
Creator Maiti, Diganta
Das, Bhabatosh
Saha, Arjun
Nandy, Ranjan K
Nair, G. Balakrish
Bhadra, Rupak K
 
Subject Infectious Diseases and Immunology
 
Description The cholera toxin (CT) is a critical determinant of the virulence of epidemic Vibrio cholerae strains.
The ctxAB operon encoding CT is part of the genome of a filamentous bacteriophage CTXW, which
may integrate as a single copy or as multiple copies in the genome of V. cholerae. The CTXW
genome is composed of RS2 (2?4 kb) and core (4?5 kb) regions. In the present study extensive
genetic mapping analyses indicated that two copies of tandemly arrayed CTX prophages are
integrated in the small chromosome of an environmental V. cholerae strain, VCE232, belonging to
serogroup O4. Further mapping revealed that the integration of prophages has occurred in the
same genetic locus of the small chromosome of VCE232 as that of V. cholerae O1 biotype El Tor
strains. Interestingly, a new type of RS2-like element 3?5 kb in size was found in the CTX prophage
genome in the small chromosome of VCE232. Cloning followed by sequencing of the new
RS2-like element of VCE232 revealed the presence of three ORFs, which probably encode highly
divergent types of phage regulatory proteins. Furthermore, the strain VCE232 also harbours two
copies of a tandemly arranged CTX prophage devoid of the ctxAB genes, called pre-CTX
prophage, in its large chromosome. The presence of multiple copies of diverse CTX prophages in
both the chromosomes of VCE232 suggests that toxigenic environmental V. cholerae
non-O1, non-O139 strains could play a role in the emergence of new epidemic clones.
 
Date 2006
 
Type Article
PeerReviewed
 
Format application/pdf
 
Identifier http://www.eprints.iicb.res.in/416/1/MICROBIOLOGY%2DSGM_%2C__152_%2C3633%2D3641[8].pdf
Maiti, Diganta and Das, Bhabatosh and Saha, Arjun and Nandy, Ranjan K and Nair, G. Balakrish and Bhadra, Rupak K (2006) Genetic organization of pre-CTX and CTXn prophages in the genome of an environmental Vibrio cholerae non-O1, non-O139 strain. Microbiology-SGM, 152. pp. 3633-3641.
 
Relation http://dx.doi.org/10.1099/mic.0.2006/000117-0
http://www.eprints.iicb.res.in/416/