title: Extraction of violacein from Chromobacterium violaceum provides a new quantitative bioassay for N-acyl homoserine lactone autoinducers.
abstract: 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-Tn5 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.
authors.affiliation: Department of Biology, University of South Florida, Tampa 33620, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Blosser
authors.forename: K M
authors.initials: KM
authors.lastname: Gray
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism; D001681:Biological Assay; D002851:Chromatography, High Pressure Liquid; D002861:Chromobacterium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D017077:Culture Media, Conditioned; D007211:Indoles / Q000302:isolation & purification / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D017077:Culture Media, Conditioned; D007211:Indoles; C088386:homoserine lactone; D015107:4-Butyrolactone; C063155:violacein