Vibrio cholerae
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| Vibrio cholerae | ||||||||||||||
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| Vibrio cholerae Pacini 1854 |
Vibrio cholerae (also Kommabacillus) is a gram negative bacterium with a curved-rod shape that causes cholera in humans.[1][2] V. cholerae and other species of the genus Vibrio belong to the gamma subdivision of the Proteobacteria. There are two major strains of V. cholerae, classic and El Tor, and numerous other serogroups.
V. cholerae was first isolated as the cause of cholera by Italian anatomist Filippo Pacini in 1854, but his discovery was not widely known until Robert Koch, working independently thirty years later, publicized the knowledge and the means of fighting the disease.[citation needed]
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[edit] Habitat
V. cholerae occurs naturally in the plankton of fresh, brackish, and salt water, attached primarily to copepods in the zooplankton. Coastal cholera outbreaks typically follow zooplankton blooms. This makes cholera a typical zoonosis.
[edit] Pathogenesis
V. cholerae colonizes the gastrointestinal tract, where it adheres to villi. Additionally, it produces two different proteases called chitinase and mucinase. Chitinase is responsible for the ability of Vibrio cholerae to enter copapods. Mucinase is a non-specific protease that assists entry into the human gastro-intestinal tract.
Vibrio cholerae produces what is called a ZOT toxin, termed as "Zona Occludans Toxin". This toxin specifically attacks the zona occludans or "tight" junctions joining epithelial cells.
[edit] Genomics and Evolution
The 4.0 Mbp genome of N16961, an O1 serogroup, El Tor biotype, 7th pandemic strain of V. cholerae, is comprised of two circular chromosomes of unequal size that are predicted to encode a total of 3,885 genes. The genomic sequence of this representative strain has furthered our understanding of the genetic and phenotypic diversity found within the species V. cholerae. Sequence data have been used to identify horizontally acquired sequences, dissect complex regulatory and signaling pathways, and develop computational approaches to predict patterns of gene expression and the presence of metabolic pathway components. Microarrays are being used to study the evolution of the organism. Genomic sequencing of additional strains, subtractive hybridization studies and the introduction of new model systems have also contributed to the identification of novel sequences and pathogenic mechanisms associated with other strains.[2]
[edit] See also
[edit] References
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill. ISBN 0838585299.
- ^ a b Faruque SM; Nair GB (editors). (2008). Vibrio cholerae: Genomics and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-33-2 .
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