title: The role of the QseC quorum-sensing sensor kinase in colonization and norepinephrine-enhanced motility of Salmonella enterica serovar Typhimurium.
abstract: Transcriptional analysis of Salmonella enterica serovar Typhimurium (S. Typhimurium) in the presence of the mammalian hormone norepinephrine revealed up-regulation of genes in the flagellar and chemotaxis regulon. Motility assays confirmed enhanced motility of wild-type S. Typhimurium in the presence of norepinephrine that could be blocked by the alpha-adrenergic antagonist, phentolamine. Furthermore, a mutation in the qseC gene, encoding the sensor kinase of the two-component QseBC quorum-sensing system, also diminished motility of S. Typhimurium. To investigate the role of S. Typhimurium QseC in vivo, 13-week old pigs were intranasally inoculated with equal concentrations (1 x 10(9)CFU) of wild-type S. Typhimurium and a qseC mutant. Over a 1-week competitive index experiment, the qseC mutant displayed decreased colonization of the gastrointestinal tract compared to the wild-type parent strain. Thus, this study has identified a role for the QseBC quorum-sensing signal transduction system in motility and swine colonization of S. Typhimurium. Cross-talk between cell-cell communication systems in Salmonella (quorum sensing) and host hormones may explain opportunistic behaviors of the pathogen, such as immune evasion and stress-induced recrudescence of Salmonella, during fluctuations of host hormone levels.
authors.affiliation: Swine Odor and Manure Management Research Unit, USDA, ARS, National Soil Tilth Laboratory, Ames, IA 50011, USA. brad.bearson@ars.usda.gov
authors.forename: Bradley L
authors.initials: BL
authors.lastname: Bearson
authors.forename: Shawn M D
authors.initials: SM
authors.lastname: Bearson
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects*; D005243:Feces / Q000382:microbiology; D005260:Female; D005408:Flagellin / Q000235:genetics; D041981:Gastrointestinal Tract / Q000382:microbiology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D053038:Quorum Sensing / Q000187:drug effects; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000502:physiology*; D013552:Swine; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D005408:Flagellin; D010770:Phosphotransferases; D009638:Norepinephrine