Chromobacterium violaceum

Scientific classification
Kingdom: Eubacteria Phylum: Proteobacteria Class: Betaproteobacteria Order: Neisseriales Family: Neisseriaceae Genus: Chromobacterium Species: violaceum
Binomial name
Chromobacterium violaceum

Description and significance

Chromobacterium violaceum is a Gram-negative rod shape bacterium that produces violet pigment - hence the name violaceum - when grown in tryptic soy broth (Chen et al, 2002).

Usually found in soils and water of tropical and subtropical regions, with temperature around 20°C-37°C as its optimal temperature; and growth would be inhibited with temperature near or below 4°C (chen et al, 2002).

Cellular Features
Gram stain	Negative
Shape	Sphere, Curved
Arrangement	Singles, Pairs, Chains
Endospores	N/A
Motility	Yes

Optimal Environment
Salinity	N/A
Oxygen Req.	Facultative
Habitats	Multiple
Optimal Temp.	25°C
Temp. Range	Mesophilic

Above tables were borrowed from the following website: [[1]]

Genome structure

Circular chromosome with a length of 4.8 Mbp, 123 RNAs. amd 4407 proteins

Genome Project > Chromobacterium violaceum ATCC 12472 project at LNCC, Brazil
Osbaldiston GW, Greve T, "Estimating adrenal cortical function in dogs with ACTH.", Cornell Vet, 1978 Jul;68(3):308-9
http://www.ncbi.nlm.nih.gov/sites/entrez

Cell structure and metabolism

Wide range of energy sources by using appropriate oxidases and reductases Metabolism: Aerobic vs. Anaerobic Aerobic – growth in minimum medium, able to digest simple sugars using the Embden-Meyerhoff, TCA cycle, and the glyoxylate cycle. Anaerobic – when oxygen availability is scarce, C. violacum decreases pyruvate dehydrogenase activity, uses pyruvates or derivatives of pyruvates as electrons and a hydrogen acceptor in the reoxidation of NADH.

Metabolism of glucose produces acetic and formic acid, not lactic acid as in other microbes.

Metabolism of Trp for production of Violacein

Besides breaking down simple sugars to produce energy, C. violaceum can also metabolize amino acids to produce keto-acids, which are then converted to Acetyl-CoA for energy production. Another non-sugar source for energy harvest would be the β-oxidation of fatty acids into reduced nucleotides and Acetyl-CoA (Creczynski-Pasa, T. B. & Antonio, R. V.).

Ecology

C. violaceum is a free-living microbe common found in soil and water of tropical and subtropical regions; its capability of arsenic resistance and cyanase production allows C. violaceum to contribute to bioremediation such as recycling CCA (chromate copper arsenate), or providing an alternative ways of mining gold from ore without using cyanide solution - cyanide spill causes environmental pollution. Nevertheless, its ability to dehalogenate toxic compounds prevents environmental degradation (Carepo et al).

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Chromobacteria do not usually cause diseases in humans, the first C. violaceum infection reported was in 1927 from Malaysia, and approximately 150 cases reported worldwide, such as Asia, USA, Australia, and Africa (Martinez & Mattar, 2007).

C. violaceum usually enters hosts through injured wounds, skin lession, cervical abscess, or the pharynx (Chen et al, 2002).

Other related infections/inflammations include: regional lymphadenopathy, facial cellulitis, and otitis Symptoms of C.violaceum infection includes but not limit to: systemic inflammation, palor, toxemia, and cyanosis (Martinez & Mattar).

Pathogenic in	Disease
Human	Diarrhea and occasionally Septicemia

Above table was taken from the following website:[[2]]

Application to Biotechnology

Ars Resistance Operon encodes the gene arsC that is transcribed into arsenate reductase, which reduces arsenate into arsenite, and then arsenites are removed from cytoplasm through efflux pumps. This could be applied to "bioremediation process, such as the recycling of CCA (chromated copper arsenate)-treated wood waste" (M.S.P. Carepo et al., 2004).

hcnABC Operon coding for HCN production which could be used in bioleaching for gold recovery; Traditionally, gold is retrieved from ores using cyanide solution through the process of cyanide heap leach process. This process is time consuming and the solution of cyanide-metal complex is stored in ponds, meaning that there is always a possibility of spillage, causing environmental pollution. hcn operon of C. violaceum provides an alternative of mining gold process called bioleaching; in which they could solubilize 100% of the gold within a week (190-91).

ORF-CV0864 (open reading frame)encodes for Acid Dehalogenase on the hcn Operon; this gives the bacterium a very beneficial biological application in detoxifying halogenated compounds that are degradative to the environment (186-7).

Violacein, a compound that forms purple color when reacted in trypic soy broth is reported to have antimicrobial, antiviral, anticancer, and bactericidal activities (Brazilian National Genome Project Consortium).

Current Research

Identification of Chromobacterium violaceum genes with potential biotechnology application in environmental detoxification M.S.P. Carepo et al. proposed the three operons in C. violaceum having pharmacological, biotechnological, and industrial properties. They are, the ars Operon, which gives rise to arsenic resistance to the baterium; cyn Operon, which is capable of cynate detoxification; and the hcn Operon that produces cyanse for biogenic production of cyanide, hcn also composed of an open reading frame (ORF) for acid dehalogenase.

Mouse and Human Cell Activation by N-dodecanoyl-DL-Homoserine Lactone, a Chromobacterium violaceum Autoinducer Homoserine lactones (HSLs) are autoinducers produced by C. violaceum for gene regulation, such as cytokines inflamation, "activation of the NF-kB signaling pathways", and quorum-sensing role.

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability Sequenced genome of C. violaceum shows that this bacterium pocesses multiple-alternative metabolism pathways, capability of adapting to a wide range of environmental stresses, having approximately '500 ORFs for transport-related' proteins; Results also shows that C. violaceum produces proteins that have "drug and heavy metal resistance", some being able to break down chitin, others having the ability to dextoxify xenobiotics.

References

Brazilian National Genome Project Consortium. (September 30, 2003). The complete genome sequence of Chomobacterium violaceum revelas remarkable and exploitable bacterial adaptability. 100, 11660-11665. Retrieved April 2, 2008, from www.pnas.org/cgi/doi/10.1073/pnas.1832124100 www.pnas.org.

Carepo, M., et al. (March 31, 2004). Identification of Chromobacterium violaceum genes with potential biotechnological application in environmental detoxification. Genetics and Molecular Research, 1(1676-5680), 181-194. Retrieved March 20, 2008, from www.funpecrp.com.br GMR.

Chen, C., et al. (September 20, 2002). Chromobacterium violaceum bacteremia: a case report. J Microbiol Immunol Infect, (36), 141-144

Creczynski-Pasa, T. B. & Antonio, R. V. (March 31, 2004). Energetic metabolism of Chromobacterium violaceum. Genetics and Molecular Research, 1(1676-5680), 162-166. Retrieved March 22, 2008, from www.funpecrp.com.br GMR

Gomi, K., et al. (September 5, 2006). Mouse and Human Cell Activation by N-Dodecanoyl-DL-Homoserine Lactone, a Chromobacterium violaceum Autoinducer. INFECTION AND IMMUNITY, 74, 7029-7031. Retrieved March 23, 2008, from www.pubmed.com

Martinez, P. & Mattar, S. (November 2007). Fatal Septicemia Caused by Chromobacterium violaceum In A Child From Colombia. 6(49), 391-393.