title: Gene expression profiling of the pH response in Shigella flexneri 2a.
abstract: The pH response of Shigella flexneri 2a 301 was identified by gene expression profiling. Gene expression profiles of cells grown in pH 4.5 or 8.6 were compared with the profiles of cells grown at pH 7.0. Differential expression was observed for 307 genes: 97 were acid up-regulated, 102 were acid down-regulated, 91 were base up-regulated, and 86 were base down-regulated. Twenty-seven genes were found to be both acid and base up-regulated, and 29 genes were both acid and base down-regulated. This study showed that (1) the most pH-dependent genes regulate energy metabolism; (2) the RpoS-dependent acid-resistance system is induced, while the glutamate-dependent acid resistance system is not; (3) high pH up-regulates some virulence genes, while low pH down-regulates them, consistent with Shigella infection of the low gut; and (4) several cross-stress response genes are induced by pH changes. These results also illustrate that many unknown genes are significantly regulated under acid or basic conditions, providing researchers with important information to characterize their function.
authors.affiliation: Department of Microbiology, Medical College of Xi' an Jiaotong University, Xi' an, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Cheng
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Junping
authors.initials: J
authors.lastname: Peng
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Hua
authors.initials: H
authors.lastname: Fu
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Xue
authors.forename: Weijun
authors.initials: W
authors.lastname: Li
authors.forename: Yonglie
authors.initials: Y
authors.lastname: Chu
authors.forename: Qi
authors.initials: Q
authors.lastname: Jin
mesh_terms: D000143:Acids / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D020411:Oligonucleotide Array Sequence Analysis; D012763:Shigella flexneri / Q000187:drug effects / Q000235:genetics*; D014774:Virulence / Q000235:genetics
chemical_list: D000143:Acids; D001426:Bacterial Proteins