Adopt a Bacterium - Chromobacterium violaceum

The Colour purple rocks!!
This is what Chromobacterium violaceum colonies look like on an agar plate.

C. violaceum are rod-shaped, Gram-negative bacteria

Chromobacterium violaceum is a facultative anaerobic, oxidase-positive, glucose-fermenting, non-lactose-fermenting, Gram-negative bacillus. It produces a possible antioxidant called violacein, a purple pigment that gives Chromobacterium violaceum its color. (7) Violacein has been studied and proven to defend microorganism membranes from oxidation or peroxidation. (8) This bacterium can also produce acid (ferment) from glucose, trehalose, N-acetylglucosamine and gluconate, but not L-arabinose, D-galactose or D-maltose. In addition, it can produce cyanide in the form of ammonium cyanide. Lastly, casein is hydrolyzed and arginine decarboxylated in the presence of this bacterium. (3) C. violaceum is also known for being a reporter strain in quorum sensing. (4) Quorum sensing is a phenomenon in which cells perform certain kinds of actions only in specific populations. It is a type of communication used by cells that allows cells to take specific actions when the population grows beyond a certain limit. (11)

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Alia Alissa
Published on Dec 11, 2016

Good overview of_ Chromobacterium violaceum_ characteristics

This summer, my student Ruth Isenberg and I have been learning about time-lapse macro photography---hoping to create "movies" of bacterial interactions.

Violacein-producing bacteria, with their striking purple hues, have undoubtedly piqued the curiosity of scientists since their first discovery. The bisindole violacein is formed by the condensation of two tryptophan molecules through the action of five proteins. The genes required for its production, vioABCDE, and the regulatory mechanisms employed have been studied within a small number of violacein-producing strains. As a compound, violacein is known to have diverse biological activities, including being an anticancer agent and being an antibiotic against Staphylococcus aureus and other Gram-positive pathogens. Identifying the biological roles of this pigmented molecule is of particular interest, and understanding violacein’s function and mechanism of action has relevance to those unmasking any of its commercial or therapeutic benefits. Unfortunately, the production of violacein and its related derivatives is not easy and so various groups are also seeking to improve the fermentative yields of violacein through genetic engineering and synthetic biology. This review discusses the recent trends in the research and production of violacein by both natural and genetically modified bacterial strains.