Cheng Fan, Wang Jing, Peng Junping, Yang Jian, Fu Hua, Zhang Xiaobing, Xue Ying, Li Weijun, Chu Yonglie, Jin Qi
Department of Microbiology, Medical College of Xi' an Jiaotong University, Xi' an, China.
FEMS Microbiol Lett. 2007 May;270(1):12-20. doi: 10.1111/j.1574-6968.2007.00647.x. Epub 2007 Feb 5.
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.
通过基因表达谱分析确定了福氏志贺菌2a 301的pH响应。将在pH 4.5或8.6条件下生长的细胞的基因表达谱与在pH 7.0条件下生长的细胞的基因表达谱进行比较。观察到307个基因存在差异表达：97个基因在酸性条件下上调，102个基因在酸性条件下下调，91个基因在碱性条件下上调，86个基因在碱性条件下下调。发现27个基因在酸性和碱性条件下均上调，29个基因在酸性和碱性条件下均下调。这项研究表明：（1）大多数依赖pH的基因调控能量代谢；（2）诱导了RpoS依赖性抗酸系统，而谷氨酸依赖性抗酸系统未被诱导；（3）高pH上调一些毒力基因，而低pH下调这些基因，这与志贺菌在肠道下段的感染情况一致；（4）pH变化诱导了一些交叉应激反应基因。这些结果还表明，许多未知基因在酸性或碱性条件下受到显著调控，为研究人员提供了表征其功能的重要信息。
