Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/28/2007
Publication Date: 8/28/2007
Citation: Jesudhasan, P.R., Cepeda, M.L., Widmer, K., Dowd, S.E., Soni, K.A., Hume, M.E., Zhu, J., Pillai, S.D. 2007. Gene regulation of Salmonella enterica serovar Typhimurium as influenced by LuxS/AI-2 [abstract]. American Society for Microbiology Cell to Cell Communication in Bacteria Abstracts, October 7-10, 2007, Austin, Texas. No. 111B.
Technical Abstract: Quorum sensing is mediated by small signaling molecules, autoinducer molecules. The luxS gene which is conserved in several Gram-positive and Gram-negative bacteria is involved in the synthesis of the autoinducer molecule-2 (AI-2). Genes controlled by luxS in S. Typhimurium were identified using microarrays from wild type Salmonella Typhimurium and its isogenic luxS mutant, in two growth conditions (presence and absence of glucose), and at two different time points (mid-log and early-stationary phase). Minimal differential gene expression was observed in the presence of glucose. In the absence of glucose, a total of 1560 genes were differentially expressed; 1361 genes were identified as luxS/AI-2-regulated at the mid-log phase and 199 genes at the early-stationary phase with a significant P<0.05. The microarray results were validated by performing quantitative real-time PCR on selected genes. The results suggest that although the expression of the luxS gene in Salmonella Typhimurium is independent of the growth condition, its role in the production of AI-2 and the regulation of genes depends on the growth condition. It was found that luxS/AI-2 plays a vital role in a variety of processes such as metabolism, virulence gene expression, motility, transcription, and translation. AI-2 was observed to control several key virulence genes.