Kawada-Matsuo Miki, Tatsuno Ichiro, Arii Kaoru, Zendo Takeshi, Oogai Yuichi, Noguchi Kazuyuki, Hasegawa Tadao, Sonomoto Kenji, Komatsuzawa Hitoshi
Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Appl Environ Microbiol. 2016 Sep 16;82(19):5930-9. doi: 10.1128/AEM.01897-16. Print 2016 Oct 1.
Two-component systems (TCSs) are regulatory systems in bacteria that play important roles in sensing and adapting to the environment. In this study, we systematically evaluated the roles of TCSs in the susceptibility of the group A Streptococcus (GAS; Streptococcus pyogenes) SF370 strain to several types of lantibiotics. Using individual TCS deletion mutants, we found that the deletion of srtRK (spy_1081-spy_1082) in SF370 increased the susceptibility to nisin A, which is produced by Lactococcus lactis ATCC 11454, but susceptibility to other types of lantibiotics (nukacin ISK-1, produced by Staphylococcus warneri, and staphylococcin C55, produced by Staphylococcus aureus) was not altered in the TCS mutants tested. The expression of srtFEG (spy_1085 to spy_1087), which is located downstream of srtRK and is homologous to ABC transporters, was increased in response to nisin A. However, srtEFG expression was not induced by nisin A in the srtRK mutant. The inactivation of srtFEG increased the susceptibility to nisin A. These results suggest that SrtRK controls SrtFEG expression to alter the susceptibility to nisin A. Further experiments showed that SrtRK is required for coexistence with L. lactis ATCC 11454, which produces nisin A. Our results elucidate the important roles of S. pyogenes TCSs in the interactions between different bacterial species, including bacteriocin-producing bacteria.
In this study, we focused on the association of TCSs with susceptibility to bacteriocins in S. pyogenes SF370, which has no ability to produce bacteriocins, and reported two major new findings. We demonstrated that the SrtRK TCS is related to susceptibility to nisin A by controlling the ABC transporter SrtFEG. We also showed that S. pyogenes SrtRK is important for survival when the bacteria are cocultured with nisin A-producing Lactococcus lactis This report highlights the roles of TCSs in the colocalization of bacteriocin-producing bacteria and non-bacteriocin-producing bacteria. Our findings provide new insights into the function of TCSs in S. pyogenes.
双组分系统（TCSs）是细菌中的调节系统，在感知和适应环境方面发挥着重要作用。在本研究中，我们系统地评估了TCSs在A群链球菌（GAS；化脓性链球菌）SF370菌株对几种类型羊毛硫抗生素敏感性中的作用。使用单个TCS缺失突变体，我们发现SF370中srtRK（spy_1081-spy_1082）的缺失增加了对乳酸乳球菌ATCC 11454产生的乳链菌肽A的敏感性，但在所测试的TCS突变体中，对其他类型羊毛硫抗生素（华纳葡萄球菌产生的努卡霉素ISK-1和金黄色葡萄球菌产生的葡萄球菌素C55）的敏感性没有改变。位于srtRK下游且与ABC转运蛋白同源的srtFEG（spy_1085至spy_1087）的表达在响应乳链菌肽A时增加。然而，在srtRK突变体中，乳链菌肽A并未诱导srtEFG表达。srtFEG的失活增加了对乳链菌肽A的敏感性。这些结果表明，SrtRK控制SrtFEG的表达以改变对乳链菌肽A的敏感性。进一步的实验表明，SrtRK是与产生乳链菌肽A的乳酸乳球菌ATCC 11454共存所必需的。我们的结果阐明了化脓性链球菌TCSs在不同细菌物种（包括产细菌素的细菌）之间相互作用中的重要作用。
在本研究中，我们关注了无产生细菌素能力的化脓性链球菌SF370中TCSs与对细菌素敏感性的关联，并报告了两个主要的新发现。我们证明，SrtRK TCS通过控制ABC转运蛋白SrtFEG与对乳链菌肽A的敏感性相关。我们还表明，当化脓性链球菌与产生乳链菌肽A的乳酸乳球菌共培养时，SrtRK对其生存很重要。本报告强调了TCSs在产细菌素细菌和不产细菌素细菌共定位中的作用。我们的发现为化脓性链球菌中TCSs的功能提供了新的见解。
