Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
Microbiology (Reading). 2011 Nov;157(Pt 11):3187-3194. doi: 10.1099/mic.0.050534-0. Epub 2011 Aug 26.
The virulence of Streptococcus pyogenes depends on proteins that are produced by this bacterium. The production of virulence proteins depends on environmental factors, and two-component regulatory systems are considered to be involved in sensing these factors. One of the environmental factors is acid stimuli. We established knockout strains in all speculated two-component regulatory sensor proteins of the M1 clinical strain of S. pyogenes and examined their relevance to acid stimuli. The parental strain and its derived knockout strains were cultured in a medium adjusted to pH 7.6 or 6.0, and their growth in broth was compared. The spy1622 sensor knockout strain showed significant growth reduction compared with the parental strain in broth at pH 6.0, suggesting that the Spy1622 two-component sensor protein is involved in sensing acid stimuli. To further examine the role of the Spy1622 two-component sensor protein in virulence, blood bactericidal assays and mouse infection model experiments were performed. We found that the spy1622 knockout strain was less virulent than the parental strain, which suggests that the Spy1622 two-component sensor protein could play an important role in virulence.
化脓链球菌的毒力取决于该细菌产生的蛋白质。毒力蛋白的产生取决于环境因素，而双组分调节系统被认为参与了这些因素的感应。环境因素之一是酸刺激。我们在化脓链球菌 M1 临床株的所有推测的双组分调节传感器蛋白中建立了敲除株，并研究了它们与酸刺激的相关性。将亲本株及其衍生的敲除株在 pH 值为 7.6 或 6.0 的培养基中培养，并比较其在肉汤中的生长情况。Spy1622 传感器敲除株在 pH 值为 6.0 的肉汤中的生长明显低于亲本株，表明 Spy1622 双组分传感器蛋白参与了酸刺激的感应。为了进一步研究 Spy1622 双组分传感器蛋白在毒力中的作用，进行了血液杀菌测定和小鼠感染模型实验。我们发现，spy1622 敲除株的毒力比亲本株低，这表明 Spy1622 双组分传感器蛋白在毒力中可能发挥重要作用。
