Latest Research on Chromobacterium: Jan – 2020

Autotoxic antibiotic production by a marine Chromobacterium

An antibiotic-producing Chromobacter was isolated from a sea-water sample from the North Pacific Gyre. The bacterium produces 3 bromine-containing metabolites: tetrabromopyrrole, 2-(2′-hydroxy-3′, 5′-dibromophenyl)-3, 4, 5-tribromopyrrole, and hexabromo-2, 2′-bipyrrole. It also synthesizes n-propyl 4-hydroxybenzoate and 4-hydroxybenzaldehyde. a number of these compounds were shown to be liable for autoinhibition of the Chromobacterium itself, also as for antibiotic action against other forms of bacteria. [1]

Chromobacterium violaceum: A Review of Pharmacological and Industiral Perspectives

Violet-pigmented bacteria, which are described since the top of the 19th century, are occasionally the causative agent of septicemia and sometimes cause fatal infection in human and animals. Bacteria, producing violet colonies thanks to the assembly of a nondiffus-ible pigment violacein, were classified as a redefined genus Chromobacterium. Chromobacterium violaceum is Gram-negative, and saprophyte from soil and water is generally considered nonpathogenic to human, but is an opportunistic pathogen of utmost virulence for human and animals. The biosynthesis and biological activities of violacein and therefore the diverse effects of this pigment are studied. Besides violacein, C. violaceum produces other antibiotics, like aerocyanidin and aerocavin, which exhibit in vitro activity against both Gram-negative and Gram-positive bacteria. [2]

Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones

Quorum sensing relies upon the interaction of a diffusible signal molecule with a transcriptional activator protein to couple organic phenomenon with cell population density. In Gram-negative bacteria, such signal molecules are usually N-acylhomoserine lactones (AHLs) which differ within the structure of their N-acyl side chains. Chromobacterium violaceum, a Gram-negative bacterium commonly found in soil and water, produces the characteristic purple pigmen violacein. Previously the authors described a violacein-negative, mini-Tn5 mutant of C. violaceum (CV026) during which pigment production are often restored by incubation with supernatants from the wild-type strain. To develop this mutant as a general biosensor for AHLs, the natural C. violaceum AHL molecule was first chemically characterized. By using solvent extraction, HPLC and mass spectrometry, one AHL, N-hexanoyl-L-homoserine lactone (HHL), was identified in wild-type C. violaceum culture supernatants which was absent from CV026. Since the assembly of violacein constitutes an easy assay for the detection of AHLs, we explored the power of CV026 to reply to a series of synthetic AHL and N-acylhomocysteine thiolactone (AHT) analogues. [3]

Chromobacterium spp. mediate their anti-Plasmodium activity through secretion of the histone deacetylase inhibitor romidepsin

The Chromobacterium sp. Panama bacterium has in vivo and in vitro anti-Plasmodium properties. To assess the character of the Chromobacterium-produced anti-Plasmodium factors, chemical partition was conducted by bioassay-guided fractionation where different fractions were assayed for activity against asexual stages of P. falciparum. The isolated compounds were further partitioned by reversed-phase FPLC followed by size-exclusion chromatography; high resolution UPLC and ESI/MS data were then collected and revealed that the foremost active fraction contained a cyclic depsipeptide, which was identified as romidepsin. [4]

Anti-Quorum Sensing Activity of Tetracera scandens and Aleurites moluccana Leaf Extracts against Chromobacterium violaceum

Aims: to check the efficacy of Tetracera scandens (L.) Merr. and candlenut (L.) Wiild. methanolic leaf extracts on the inhibition of quorum sensing-dependent pigmentation of Chromobacterium violaceum.

Study design: In-vitro quorum sensing inhibition design was conducted.

Place and Duration of Study: The study was conducted at the biology lab , College of Science, Pamantasan ng Lungsod ng Maynila between November 2015 to May 2016.

Methodology: The leaf extracts were obtained through soaking in methanol and subsequent rotary evaporation. Qualitative screening of the anti-quorum sensing activities of the extracts were done through Agar Well Diffusion Assay. The Minimum Quorum Sensing Inhibition Concentration decided through two-fold serial dilution then wells were streaked on Mueller-Hinton Agar plates to spot the Minimum Bactericidal Concentration. Disc Diffusion Assay was done to quantitatively measure the anti-quorum sensing activities of the leaf extracts. [5]

Reference

[1] Andersen, R.J., Wolfe, M.S. and Faulkner, D.J., 1974. Autotoxic antibiotic production by a marine Chromobacterium. Marine Biology, 27(4), (Web Link)

[2] Durán, N. and Menck, C.F., 2001. Chromobacterium violaceum: a review of pharmacological and industiral perspectives. Critical reviews in microbiology, 27(3), (Web Link)

[3] McClean, K.H., Winson, M.K., Fish, L., Taylor, A., Chhabra, S.R., Camara, M., Daykin, M., Lamb, J.H., Swift, S., Bycroft, B.W. and Stewart, G.S., 1997. Quorum sensing and Chromobacterium violaceum: exploitation of violacein production and inhibition for the detection of N-acylhomoserine lactones. Microbiology, 143(12), (Web Link)

[4] Chromobacterium spp. mediate their anti-Plasmodium activity through secretion of the histone deacetylase inhibitor romidepsin
Raúl G. Saraiva, Callie R. Huitt-Roehl, Abhai Tripathi, Yi-Qiang Cheng, Jürgen Bosch, Craig A. Townsend & George Dimopoulos
Scientific Reports volume 8, (Web Link)

[5] D. Guzman, J. P. and Padilla, L. V. (2017) “Anti-Quorum Sensing Activity of Tetracera scandens and Aleurites moluccana Leaf Extracts against Chromobacterium violaceum”, Microbiology Research Journal International, 22(1), (Web Link)

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