title: Relevance of the two-component sensor protein CiaH to acid and oxidative stress responses in Streptococcus pyogenes.
abstract: BACKGROUND
  The production of virulence proteins depends on environmental factors, and two-component regulatory systems are involved in sensing these factors. We previously established knockout strains in all suspected two-component regulatory sensor proteins of the emm1 clinical strain of S. pyogenes and examined their relevance to acid stimuli in a natural atmosphere. In the present study, their relevance to acid stimuli was re-examined in an atmosphere containing 5% CO2.
  
  
  RESULTS
  The spy1236 (which is identical to ciaHpy) sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1236 (CiaHpy) two-component sensor protein is involved in acid response of S. pyogenes. CiaH is also conserved in Streptococcus pneumoniae, and it has been reported that deletion of the gene for its cognate response regulator (ciaRpn) made the pneumococcal strains more sensitive to oxidative stress. In this report, we show that the spy1236 knockout mutant of S. pyogenes is more sensitive to oxidative stress than the parental strain.
  
  
  CONCLUSIONS
  These results suggest that the two-component sensor protein CiaH is involved in stress responses in S. pyogenes.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tatsuno
authors.forename: Masanori
authors.initials: M
authors.lastname: Isaka
authors.forename: Ryo
authors.initials: R
authors.lastname: Okada
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi Mizuho-cho Mizuho-ku, Nagoya 467-8601, Japan. tadaoh@med.nagoya-cu.ac.jp.
authors.forename: Tadao
authors.initials: T
authors.lastname: Hasegawa
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D018384:Oxidative Stress; D011494:Protein Kinases / Q000172:deficiency / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D011494:Protein Kinases