中文摘要：

目的：研究在大肠杆菌密度感应缺陷株中表达LuxS蛋白对于生物膜形成相关基因的影响。方法：在大肠杆菌密度感应缺陷株MDA12中表达LuxS蛋白，继而通过Real-time PCR检测菌株间生物膜形成相关基因的表达差异。结果：野生株中生物膜形成相关基因motA、motB表达量约为MDA12的2～5倍，而表达了LuxS蛋白的MDA12中该基因的表达量则为6-8倍，且差异具有统计学意义。结论：大肠杆菌密度感应缺陷株内表达LuxS，可以恢复其密度感应系统继而恢复生物膜形成相关基因的表达。

英文摘要：

Objective： To investigate the effection of expressing LuxS in E. coli quorum sensing defective strain on its biofilm--related genes. Methods： The LuxS protein was expressed in the E. coli quorum sensing defective strain MDAI2. The biofilm--related genes were investigated by real--time PCR. Results： Compared to MDAI2, the bio- film--related genes motA and motB expressed about 2--fold to 5--fold in wild--type strain. When expressed LuxS in MDAI2, these genes expressed more than the defective strain about 6--fold to 8--fold, and the differences were statistically significant. Conclusion： The biofilm--related genes could be recovered by expressing the LuxS protein in quorum sensing defective strain of E. coli.