title: Identification of Salmonella enterica serovar Typhimurium genes associated with growth suppression in stationary-phase nutrient broth cultures and in the chicken intestine.
abstract: Over 2,800 Tn 5 insertion mutants of Salmonella enterica sv. Typhimurium were screened for the loss of ability to suppress the multiplication of a spectinomycin-resistant (Spc(r)) but otherwise isogenic S. enterica sv. Typhimurium strain, when the Spc(r) mutant was added to 24-h LB broth cultures of the mutants. Selected "growth non-suppressive" (GNS) mutants were defective in respiration (insertions in arcA and fnr), amino acid biosynthesis (aroA and aroD), nutrient uptake and its regulation (tdcC and crp), and chemotaxis (fliD). In the last GNS mutant, the transposon inactivated yhjH, an ORF with unknown function which shows sequence similarity to di-guanylate cyclase and to novel two-component signal transduction proteins. In newly hatched chickens, all of the mutants, with the exception of the fliDmutant, were also unable to suppress colonization of the alimentary tract by the parent strain inoculated 1 day later. Defined mutations in luxS or sdiA,genes which contribute to quorum sensing in S. enterica sv. Typhimurium, had no effect on the stationary-phase growth suppression. Analysis of a transcriptional fusion construct indicated that yhjH was moderately expressed in the exponential phase of growth and up-regulated upon entry into stationary phase. Expression of yhjH was also considerably suppressed by the addition of supernatant from a 24-h stationary-phase S. enterica sv. Typhimurium culture, suggesting that the gene belongs to a new sensing and signaling regulatory pathway in S. enterica sv. Typhimurium.
authors.affiliation: Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic.
authors.forename: Ivan
authors.initials: I
authors.lastname: Rychlik
authors.forename: Gerald
authors.initials: G
authors.lastname: Martin
authors.forename: Ulrich
authors.initials: U
authors.lastname: Methner
authors.forename: Margaret
authors.initials: M
authors.lastname: Lovell
authors.forename: Lenka
authors.initials: L
authors.lastname: Cardova
authors.forename: Alena
authors.initials: A
authors.lastname: Sebkova
authors.forename: Mojmor
authors.initials: M
authors.lastname: Sevcik
authors.forename: Jiri
authors.initials: J
authors.lastname: Damborsky
authors.forename: Paul A
authors.initials: PA
authors.lastname: Barrow
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D013437:Carbon-Sulfur Lyases; D002465:Cell Movement; D002645:Chickens; D003470:Culture Media; D004251:DNA Transposable Elements / Q000235:genetics; D005798:Genes, Bacterial / Q000502:physiology*; D007422:Intestines / Q000382:microbiology*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D012486:Salmonella typhimurium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004251:DNA Transposable Elements; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria