title: Genetic mechanisms underlying the pathogenicity of cold-stressed Salmonella enterica serovar typhimurium in cultured intestinal epithelial cells.
abstract: Salmonella encounters various stresses in the environment and in the host during infection. The effects of cold (5°C, 48 h), peroxide (5 mM H2O2, 5 h) and acid stress (pH 4.0, 90 min) were tested on pathogenicity of Salmonella. Prior exposure of Salmonella to cold stress significantly (P < 0.05) increased adhesion and invasion of cultured intestinal epithelial (Caco-2) cells. This increased Salmonella-host cell association was also correlated with significant induction of several virulence-associated genes, implying an increased potential of cold-stressed Salmonella to cause an infection. In Caco-2 cells infected with cold-stressed Salmonella, genes involved in the electron transfer chain were significantly induced, but no simultaneous significant increase in expression of antioxidant genes that neutralize the effect of superoxide radicals or reactive oxygen species was observed. Increased production of caspase 9 and caspase 3/7 was confirmed during host cell infection with cold-stressed Salmonella. Further, a prophage gene, STM2699, induced in cold-stressed Salmonella and a spectrin gene, SPTAN1, induced in Salmonella-infected intestinal epithelial cells were found to have a significant contribution in increased adhesion and invasion of cold-stressed Salmonella in epithelial cells.
authors.affiliation: Department of Dietetics, Nutrition and Food Sciences, Utah State University, Logan, Utah, USA School of Veterinary Medicine, Department of Population Health and Reproduction, University of California, Davis, California, USA.
authors.forename: Jigna
authors.initials: J
authors.lastname: Shah
authors.affiliation: Department of Dietetics, Nutrition and Food Sciences, Utah State University, Logan, Utah, USA School of Veterinary Medicine, Department of Population Health and Reproduction, University of California, Davis, California, USA.
authors.forename: Prerak T
authors.initials: PT
authors.lastname: Desai
authors.affiliation: School of Veterinary Medicine, Department of Population Health and Reproduction, University of California, Davis, California, USA bcweimer@ucdavis.edu.
authors.forename: Bart C
authors.initials: BC
authors.lastname: Weimer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018938:Caco-2 Cells; D003080:Cold Temperature; D004847:Epithelial Cells / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D007422:Intestines / Q000166:cytology / Q000382:microbiology*; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D013312:Stress, Physiological; D014774:Virulence
chemical_list: D001426:Bacterial Proteins