title: Transcript changes in Vibrio cholerae in response to salt stress.
abstract: Vibrio cholerae, which is a serious human intestinal pathogen, often resides and thrives in estuaries but requires major self-regulation to overcome intestinal hyperosmotic stress or high salt stress in water and food. In the present study, we selected multiple O1 and O139 group V. cholerae strains that were isolated from different regions and during different years to study their salt tolerance. Based on the mechanisms that other bacteria use to respond to high salt stress, we selected salt stress-response related genes to study the mechanisms which V. cholerae responds to high salt stress. V. cholerae strains showed salt-resistance characteristics that varied in salt concentrations from 4% to 6%. However, group O1 and group O139 showed no significant difference in the degree of salt tolerance. The primary responses of bacteria to salt stress, including Na(+) exclusion, K(+) uptake and glutamate biosynthesis, were observed in V. cholerae strains. In addition, some sigma factors were up-regulated in V. cholerae strains, suggesting that V. cholerae may recruit common sigma factors to achieve an active salt stress response. However, some changes in gene transcript levels in response to salt stress in V. cholerae were strain-specific. In particular, hierarchical clustering of differentially expressed genes indicated that transcript levels of these genes were correlated with the degree of salt tolerance. Therefore, elevated transcript levels of some genes, including sigma factors and genes involved in peptidoglycan biosynthesis, may be due to the salt tolerance of strains. In addition, high salt-tolerant strains may recruit common as well as additional sigma factors to activate the salt stress response.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155, Changbai Road, Changping, Beijing 102206 China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310006 China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Fu
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155, Changbai Road, Changping, Beijing 102206 China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310006 China.
authors.forename: Weili
authors.initials: W
authors.lastname: Liang
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155, Changbai Road, Changping, Beijing 102206 China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310006 China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Du
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155, Changbai Road, Changping, Beijing 102206 China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310006 China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Yan
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 155, Changbai Road, Changping, Beijing 102206 China ; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, 310006 China.
authors.forename: Biao
authors.initials: B
authors.lastname: Kan
keywords: PCR array; Salt stress; Transcription; Vibrio cholerae