Submitted to: American Society for Microbiology General Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 22, 2012
Publication Date: June 16, 2012
Citation: Bearson, B.L., Bearson, S.M.D., Lee, I.S. 2012. Phenotype microarray analysis of a Salmonella enterica serovar Typhimurium qseC mutant compared to a qseBC mutant and the wild-type strain [abstract]. In: Abstracts of the 112th General Meeting of the American Society for Microbiology, June 16-19, 2012, San Francisco, California. p. 228. Technical Abstract: The Salmonella enterica serovar Typhimurium QseBC two-component system has previously been shown to regulate bacterial motility and colonization potential in the porcine gastrointestinal tract. A qseC mutant has decreased bacterial motility and decreased colonization in swine. However, in the absence of both qseB and qseC genes, bacterial motility and swine colonization of the S. Typhimurium qseBC mutant is similar to the wild-type strain. Therefore, in the absence of the QseC sensor kinase, the QseB response regulator is deregulated and alters several cellular phenotypes. To investigate additional phenotypes that may be altered in a qseC mutant compared to wild-type or the qseBC mutant, phenotypic microarrays were performed using all 20 of Biolog’s phenotype microarray panels (PM). Phenotype microarray results indicate that growth was stimulated for the qseC mutant in the presence of multiple nucleotides and amino acids on PM5 compared to wild-type S. Typhimurium and the qseBC mutant. Although growth stimulation occurred on PM5, bacterial growth was not enhanced for the qseC mutant when using these nucleotides and amino acids as carbon sources on PM1 compared to the wild-type and the qseBC mutant, suggesting that growth is stimulated in a defined medium in the presence of low concentrations of nucleotides or amino acids, but these nucleotides or amino acids do not enhance bacterial growth when they are the sole carbon source. In contrast to the enhanced phenotypes for nutrient stimulation, the qseC mutant displayed chemical sensitivities to various compounds on PM11-20 compared to the wild-type and the qseBC mutant, including some antibiotics and chemicals that inhibit the cell membrane, membrane transport, and respiration. The phenotype microarray data indicates that the absence of the qseC gene causes pleiotropic effects that may contribute to the reduced competitive fitness of the qseC mutant in the swine gastrointestinal tract.