title: The impact of the LuxS mutation on phenotypic expression of factors critical for Campylobacter jejuni colonization.
abstract: Studies have collectively shown the wide impact that luxS mutation has on the expression and function of various aspects of Campylobacter jejuni virulence. Previous work from our group demonstrated that LuxS mutagenesis negatively impacts colonization of the gastrointestinal tract of several host species. To determine what is responsible for the colonization defect, we used a mechanistic approach to understand how the luxS mutation affects the expression of key physiologic factors important to the colonization ability of C. jejuni. This included expression of genes from the CmeABC efflux system, cell morphology, and motility through mucin substrate between wildtype, luxS mutant, and luxS complement of the C. jejuni strains 11168 and/or IA3902. We also measured and compared the activated methyl cycle (AMC) metabolite levels of the IA3902 luxS mutant to wildtype. Results showed that mutagenesis of the luxS gene completely disrupted the AMC with altered concentrations of AMC metabolites both upstream and downstream of LuxS. Multidrug efflux pump genes cmeABC and cmeR showed no significant changes in expression levels within the luxS mutant. Though motility through mucin was not completely unaffected by the luxS mutation, the lack of differences in cell morphology between wildtype and luxS mutant suggest that morphology is not responsible for the slight changes in mucin penetration observed in one of our luxS mutants. Though additional studies are warranted, these findings suggest that the CmeABC multi-drug efflux pump, cell morphology and mucin penetration are not major mechanisms responsible for the luxS mutant's colonization defect in its host.
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA, 50011-1134, USA.
authors.forename: Kathy T
authors.initials: KT
authors.lastname: Mou
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA, 50011-1134, USA; Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, 1800 Christensen Drive, Ames, IA, 50011-1134, USA. Electronic address: pplummer@iastate.edu.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Plummer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D016123:Campylobacter jejuni / Q000166:cytology / Q000235:genetics*; D013437:Carbon-Sulfur Lyases / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D009068:Movement; D009077:Mucins; D009154:Mutation
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D009077:Mucins; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria
keywords: AI-2/LuxS; Campylobacter jejuni; Cell morphology; Efflux pump; Motility; Mucin