Bacteria Genomes - CHROMOBACTERIUM VIOLACEUM

Chromobacterium violaceum are Gram-negative , non-sporing, non-acid fast small rods or coccobacilli. They are 0.6-0.9µm x 1.5-3.0µm in size. Motility of C. violaceum is achieved by means of a single polar flagellum and up to four antigenically and structurally distinct lateral flagellae. C. violaceum are facultative anaerobes with a growth range from 15-40C. Optimal growth is achieved at 30-35C. They are considered as normal flora of soil and water in tropical to subtropical areas where they may play a role in the rhizosphere. These bacteria are not present as part of the normal flora of humans or animals.

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world, including the Rio Negro in the Brazilian Amazon. It is possibly because C. violaceum has been forced to adapt to living in these harsh environments that is has adapted to life with a scarcity of nutrients, and high levels of radiation and other toxic threats.

Chromobacterium violaceum could be used for the production of violacein, which has antibiotic characteristics particularly against soil amoebae and trypanosomes. It can also be used to assay for L-tryptophan. C. violaceum does not regulate any of its tryptophan genes transcriptionally. It uses the amino acid tryptophan to synthesize the antibiotic violaceum. Chromobacterium violaceum also produces other antibiotics; Aerocyanidine is active against Gram-positive organisms and Aerocavin is active against Gram-positive and Gram-negative organisms.

Human infection caused by Chromobacterium violaceum is rare, but when it occurs it is associated with a high mortality rate. Human infections are reported from several continents, particularly Australia, South America, and Southeast Asia where the typical disease presentation includes cutaneous inflammation, sepsis, liver abscesses and ocular infections. Currently there are no vaccines.

It has been suggested that C. violaceum strains can be used for the extraction of gold from soil. As a result of the production of cyanide, which reacts with the gold to form the complex anion [Au(CN)2]-, the gold is solublised and easily extracted.

References:

Proc. Natl. Acad. Sci. USA 100 (20):11660-5 (2003)
Clin. Infect. Dis. (3):505-7 (1993 )
http://web.umr.edu/~microbio/BIO221_2000/Chromobacterium_violaceum.html
http://www.genomenewsnetwork.org/sequenced_genomes/genome_guide_p1a.shtml
http://www.licr.org/07_spot/091503_chromo.htm