Extraction of violacein from Chromobacterium violaceum provides a new quantitative bioassay for N-acyl homoserine lactone autoinducers

• Published in: Journal of microbiological methods Vol. 40; no. 1; pp. 47 - 55
• Main Authors: Blosser, Renée S, Gray, Kendall M
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01.03.2000; Elsevier Science
• Subjects: 4-Butyrolactone - analogs & derivatives; 4-Butyrolactone - metabolism; Acyl homoserine lactones; Acylated homoserine lactone; Bacteriological methods and techniques used in bacteriology; Bacteriology; Bioassay; Biological and medical sciences; Biological Assay; Chromatography, High Pressure Liquid; Chromobacterium; Chromobacterium - genetics; Chromobacterium - growth & development; Chromobacterium - metabolism; Chromobacterium violaceum; Culture Media, Conditioned; Fatty acyl homoserine lactones; Fundamental and applied biological sciences. Psychology; Indoles - isolation & purification; Indoles - metabolism; Microbiology; N-Hexanoyl homoserine lactone; Quorum sensing; Signal Transduction; violacein; Chromobacterium; Quorum sensing; Bioassay; Acyl homoserine lactones; Pigments; Chromobacterium violaceum; Bacteria; Method; Quantitative analysis
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/S0167-7012(99)00136-0

Fatty acyl homoserine lactones (AHLs) are used as extracellular quorum sensing signals by a variety of Gram-negative bacteria. By activating proteins belonging to the LuxR family of transcriptional regulators, these signal metabolites allow population density-dependent gene regulation within a species, as well as interspecies communication among different bacteria. The experimental detection of AHLs is important in the identification of quorum sensing capabilities in bacteria. Chromobacterium violaceum is a Gram-negative bacterium that produces the purple pigment violacein in response to the presence of the AHL N-hexanoyl homoserine lactone (C6HSL). The mini-Tn 5 mutant strain C. violaceum CV0blu is deficient in the production of this signal molecule but retains the ability to synthesize violacein in response to the presence of C6HSL and a variety of other short-chain AHLs. We have developed a quantitative bioassay that measures the amount of violacein produced by this strain in response to the presence of different concentrations of various AHL molecules. This new assay provides a means of quantifying the amount of a given AHL present in a bacterial culture and can be used to measure differences in AHL production among different strains or different batch cultures of a given species.