Bacteria utilize quorum-sensing systems to modulate environmental stress responses. The quorum-sensing system of Streptococcus mutans is mediated by the competence-stimulating peptide (CSP), whose precursor is encoded by the comC gene. A comC mutant of strain GS5 exhibited enhanced antimicrobial sensitivity to a wide variety of different agents. Since the addition of exogenous CSP did not complement this phenotype, it was determined that the increased tetracycline, penicillin, and triclosan sensitivities resulted from repression of the putative bacteriocin immunity protein gene, bip, which is located immediately upstream from comC. We further demonstrated that the inactivation of bip or smbG, another bacteriocin immunity protein gene present within the smb operon in S. mutans GS5, affected sensitivity to a variety of antimicrobial agents. Furthermore, both the bip and smbG genes were upregulated in the presence of low concentrations of antibiotics and were induced during biofilm formation relative to in planktonic cells. These results suggest, for the first time, that the antimicrobial sensitivity of a bacterium can be modulated by some of the putative bacteriocin immunity proteins expressed by the organism. The implications of these observations for the evolution of bacteriocin immunity protein genes as well as for potential new chemotherapeutic strategies are discussed.

译文

:细菌利用群体感应系统来调节环境应激反应。变异链球菌的群体感应系统由能力刺激肽(CSP)介导,其前体由comC基因编码。菌株GS5的comC突变体对多种不同的药物表现出增强的抗菌敏感性。由于外源CSP的添加不能补充该表型,因此确定增加的四环素,青霉素和三氯生敏感性是由推定的细菌素免疫蛋白基因bip抑制而来的,该基因位于comC的上游。我们进一步证明了bip或smbG(变形链球菌GS5的smb操纵子内存在的另一种细菌素免疫蛋白基因)的失活影响了对多种抗菌剂的敏感性。此外,在低浓度抗生素存在下,bip和smbG基因均被上调,并且在生物膜形成过程中相对于浮游细胞被诱导。这些结果首次表明,细菌的抗菌敏感性可以由生物体表达的某些假定的细菌素免疫蛋白来调节。讨论了这些观察结果对细菌素免疫蛋白基因的进化以及潜在的新化学治疗策略的影响。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录