小肠结肠炎耶尔森菌对多粘菌素B的压力应答

Stress response of Yersinia enterocolitica to polymyxin B

摘要:

[背景] 小肠结肠炎耶尔森菌（Yersinia enterocolitica）是重要的人畜共患食源性病原菌。由于其生存环境与传染性生活方式，小肠结肠炎耶尔森菌暴露在各种生存压力中，而胞膜压力应答能力对维持其环境耐受性和毒力发挥着重要作用。[目的] 探究小肠结肠炎耶尔森菌在胞膜压力应答中的调节机制。[方法] 通过使用多粘菌素B破坏小肠结肠炎耶尔森菌细胞膜的稳定性，并从生长能力、运动能力、生物被膜形成能力以及相关基因表达的变化探讨Rcs （Regulator of capsule synthesis）系统对多粘菌素B产生的胞膜压力的应答。[结果] 多粘菌素B引起的细胞胞膜压力抑制了小肠结肠炎耶尔森菌的运动和生物被膜形成能力；而阻断Rcs信号途径后，小肠结肠炎耶尔森菌的运动和生物被膜形成能力有所恢复。对flhC、hmsS、hmsT等关键下游表型基因的表达水平的分析结果表明Rcs双组分系统对由多粘菌素B诱导的胞膜压力作出响应，通过感知胞膜胁迫向胞内传递信号，积极地调控细菌增强对抗菌肽的抗性。[结论] 明确了Rcs双组分系统在响应多粘菌素B压力胁迫中的特异性调控作用，加深了对小肠结肠炎耶尔森菌环境应答机制的认识。

关键词:小肠结肠炎耶尔森菌;多粘菌素B;胞膜压力;压力应答;Rcs双组分系统

Abstract:

[Background] Yersinia enterocolitica, an important food-borne zoonotic pathogen, is commonly exposed to cell envelope stresses due to its living environment and epidemic properties. The envelope stress responses of Y. enterocolitica play a very important role in maintaining its environmental tolerance and virulence. [Objective] Explore the role of Y. enterocolitica in regulation of cell envelope stress. [Methods] Polymyxin B was used to disrupt the cell membrane stability of Y. enterocolitica, and we explore the response of regulator of capsule synthesis (Rcs) system to the envelop stress by polymyxin B from the changes in growth, motility ability, biofilm formation ability and related gene expression of Y. enterocolitica. [Results] The cell membrane pressure caused by polymyxin B inhibited the motility and biofilm formation of Y. enterocolitica, which were restored after blocking the Rcs signaling pathway. The expression of genes regulated by Rcs system, such as flhC, hmsS and hmsT, were analyzed. The results further confirmed the regulation of Rcs system in response to the membrane pressure induced by polymyxin B. After sensing the envelop stress signals, Rcs system could actively regulate gene expression and cause pleiotropic changes to improve the resistance of Y. enterocolitica to polymyxin B. [Conclusion] This study clarified the specific regulatory role of the Rcs system in response to membrane stress caused by polymyxin B, and will deepen the understanding of the environmental response mechanisms of Y. enterocolitica.

Key words:Yersinia enterocolitica;polymyxin B;envelope stress;stress response;regulator of capsule synthesis (Rcs) phosphorelay system