Production of pyomelanin in the Vibrio campbellii hmgA mutant results in the repression of quorum sensing, bioluminescence and virulence

ABSTRACT: Vibrio campbellii BAA-1116 was used as model organism from the Harveyi clade to understand how melanization affected cellular phenotype, metabolism and virulence. An in-frame deletion of the homogentisate-1,2-dioxygenase (hmgA) gene resulted in the overproduction of a pigment in cell culture supernatants and cellular membranes that was identified as pyomelanin. Unlike previous demonstrations in Vibrio cholerae, Burkholderia cepacia and Pseudomonas aeruginosa, the pigmented V. campbellii mutant did not show increased UV or hydrogen peroxide resistance and was found to be ~2.7 times less virulent then the wild type strain in Penaeus monodon shrimp virulence assays. Microarray-based transcriptomic analyses revealed that the deletion of the hmgA gene and subsequent pyomelanin production negatively effected the expression of 129 genes involved in protein translation, cell division, membrane transport, electron transfer and amino acid utilization. The response was mediated in part by an impairment of the quorum sensing regulon as transcripts of the quorum sensing high cell density master regulator LuxR and other operonic members of this regulon were significantly repressed in the hmgA mutant. Taken together, the results suggest that the pyomelanization of V. campbellii sufficiently impairs the metabolic activities of this organism and renders it less fit and virulent then its isogenic wild type strain. Three biological replicates of V. campbellii BAA-1116 (str) and hmgA mutants were grown to stationary phase (48 h, 200 rpm, 30M-BM-0C, in 50 mL LM medium) and total RNA was extracted from 1.0E+9 cells. Messenger RNA was isolated from the total RNA extracts treated with DNase, labeled with biotin, fragmented and hybridized to V. campbellii BAA-1116 whole genome microarrays (520694F, Affymetrix).

ORGANISM(S): Vibrio campbellii

SUBMITTER: Baochuan Lin 

PROVIDER: E-GEOD-46223 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress