细菌外膜蛋白参与革兰氏阴性细菌对异丙醇耐受的调节

细菌外膜蛋白与细菌对异丙醇耐受关系密切,但迄今为止尚未见相关研究.本文首先采用基于双向电泳(two dimensional electrophoresis,2-DE)的蛋白质组学技术,研究E.coli K-12 BW25113在有无异丙醇条件下外膜蛋白表达的差异.结果发现,外膜蛋白LamB、FadL和OmpC以及OmpT、Tsx、OmpA和OmpF在异丙醇应激条件下表达量分别上调和下调.然后通过基因敲除、补救和高表达等功能基因组学的方法,探讨这些功能外膜蛋白在异丙醇应激耐受中所起的作用,发现LamB、OmpA和OmpC在E.coli K-12 BW25113对异丙醇耐受过程中起到更重要的作用.最后,对EnvZ/OmpR双组分信号转导系统在对异丙醇耐受中的作用进行了研究,证实EnvZ/OmpR双组分信号转导系统确实参与细菌对异丙醇的耐受.因此,外膜蛋白的改变和EnvZ/OmpR双组分信号转导系统的调节是革兰氏阴性细菌对异丙醇耐受的一种重要机制。

Outer Membrane Proteins are Involved in the Regulation of Isopropanol Tolerance of Gram Negative Bacteria

To study the relationship between outer membrane proteins (OMPs) and bacterial isopropanol tolerance, we characterized E.coli K-12 BW25113 OMPs function related to isopropanol tolerance at the sub-proteome level to understand tolerance mechanism of bacteria to disinfectant. Two dimensional electrophoresis (2-DE) and mass spectrometry (MS) technologies were used to identify differential expression of OMPs of E.coli K-12 BW25113 in response to isopropanol stress. Up-regulation of LamB, FadL and OmpC, and down-regulation of OmpT, Tsx, OmpA and OmpF were detected. Furthermore, we investigated roles of these altered proteins in resistance to the disinfectant through gene knockout, complementation and overexpression. Our results showed that LamB, OmpA and OmpC played more important role in the resistance than the others. Finally, we characterized the ability of EnvZ/OmpR two-component signal transduction system in exposure to disinfectant. These results indicated the importance of OMPs and EnvZ/OmpR two-component signal transduction system in response to isopropanol.