In silicocomparative studyof the genomic islandsof Vibrio cholerae MJ1236with those ofClassical and El TorN16961strains of Vibrio cholerae
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
In silicocomparative studyof the genomic islandsof Vibrio cholerae
MJ1236with those ofClassical and El TorN16961strains of
Vibrio cholerae
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| Creator |
Dutta, Avirup
Kundu, Jayanta Kumar Kundu, Raghunath Chaudhuri, Keya |
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| Subject |
Molecular & Human Genetics
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| Description |
The evolution of microbial genomes is greatly influenced by horizontal gene
transfer (HGT), where large blocks of horizontally acquired foreign sequences,
often encoding virulence determinants, occur in chromosomes of pathogenic
bacteria. A program DESIGN-ISLAND developed in our laboratory was used on three
completely sequenced Vibrio cholerae genomes, V. cholerae Classical O395, El Tor
N16961 and MJ1236, in order to identify the putative horizontally acquired
regions. The putative genomic islands (GIs) were graphically represented and
analyzed. The study identified distinct regions in the GIs of V. cholerae MJ1236
which were shared either with the Classical or the El Tor strain of V. cholerae. A
cluster comprising of 38 ORFs was common to V. cholerae strains of MJ1236 and
Classical O395 but absent in El Tor N16961. About 5% of the predicted GIs of V.
cholerae MJ1236 were unique to itself. Among these unique ORFs, a region of
mostly hypothetical genes was identified, where the ORFs were present in a large
cluster. The results show that the HGT had played a significant role in the
evolution and the differentiation of V. cholerae MJ1236.
Introduction
Vibrio cholerae, a Gram-negative bacterium, is the etiological
agent of epidemic cholera, that causes a severe and
sometimes lethal diarrheal disease. Vibrio cholerae is classified
into two serogroups: O1 and non-O1. So far, the
toxigenic strains of serogroups O1 and O139 have been
found to cause cholera epidemics. There are two biotypes of
V. cholerae O1, Classical and El Tor. There have been seven
major pandemics since 1817. Isolates of the sixth pandemic
were of O1 classical biotype, whereas the seventh pandemic,
which started in 1961, is associated with El Tor biotype
(Chaudhuri & Chatterjee, 2009). This indicated that a
transition might have occurred, which largely replaced the
V. cholerae Classical by V. cholerae El Tor as the causative
organism for pandemicity between 1905 and 1961. In 1994,
the new Matlab variants of V. cholerae El Tor replaced the
seventh pandemic O1 El Tor strains in Asia and Africa as the
predominant isolate from clinical cases of cholera (Safa
et al., 2008).
In V. cholerae, the two major virulence factors, cholera
toxin (CT) and toxin coregulated pili (TCP), have been
reported to be encoded on mobile genetic elements. The
ctxAB genes, coding for A and B subunits of CT, are encoded
on a filamentous bacteriophage CTXj. TCP, an essential
colonization factor, was originally designated as part of a
pathogenicity island named Vibrio pathogenicity island
(VPI), but this island has more recently been proposed to
be the genome of a filamentous phage, VPIj (Karaolis et al.,
1999). It is well known that the genome organization of
these V. cholerae strains and several other organisms of
related Vibrio species are generally very similar (Tagomori
et al., 2002). Interestingly, the CTXj region of the Matlab
variant of V. cholerae had properties of the CTXj region of
FEMS Microbiol Lett 321 (2011) 75–81 �c 2011 Federation of European Microbiological Societies.
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| Date |
2011
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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/34/1/FEMS_MICROBIOLOGY_LETTERS__321(1)75%2D81_;2011[14].pdf
Dutta, Avirup and Kundu, Jayanta Kumar and Kundu, Raghunath and Chaudhuri, Keya (2011) In silicocomparative studyof the genomic islandsof Vibrio cholerae MJ1236with those ofClassical and El TorN16961strains of Vibrio cholerae. FEMS Microbiol Lett, 321 (1). pp. 75-81. |
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| Relation |
http:/dx.doi.org/10.1111/j.1574-6968.2011.02316.x
http://www.eprints.iicb.res.in/34/ |
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