title: [Role of Luxs gene on regulation of virulence factors in Salmonella typhimurium].
abstract: OBJECTIVE
  To investigate the role of Luxs gene on the regulation of virulence factors in Salmonella typhimurium.
  
  
  METHODS
  Luxs gene knock-out strain of Salmonella typhimurium of the line 14028S was constructed. Media with Luxs gene knock-out 14028S or wild type 14028S bacteria were added into the media of cultured human intestinal epithelial cells of the line Caco. The numbers of colony formation unit (cfu) were calculated so as to compare the invasion ability. Northern blotting was performed to examine the Luxs gene expression.
  
  
  RESULTS
  When the 14028S cells were in the early logarithmic phase the cfu number was 590, and in the middle and late logarithmic, and stationary phases, the cfu numbers were 246, 57, and 13 respectively. The Luxs gene expression levels increased gradually along with the bacterial growth into different phases. The cfu number A600 nm = 0.25 of the Luxs gene knock-out strain was 597, significantly higher than that of the wild type (315, P < 0.05).
  
  
  CONCLUSIONS
  Luxs gene may be a negative regulator on the invasion ability of Salmonella typhimurium.
authors.affiliation: Institute of Gastroenterology, Fujian Provincial Hospital, Fuzhou 350001, China. mhchen9035@yahoo.com.cn
authors.forename: Ming-hong
authors.initials: MH
authors.lastname: Chen
authors.forename: Zhi-hui
authors.initials: ZH
authors.lastname: Lin
authors.forename: Xiao-wei
authors.initials: XW
authors.lastname: Peng
authors.forename: Xiu-zhen
authors.initials: XZ
authors.lastname: Pan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D018938:Caco-2 Cells; D013437:Carbon-Sulfur Lyases / Q000235:genetics*; D017077:Culture Media, Conditioned; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D012486:Salmonella typhimurium / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria