粪肠球菌的大量增殖并形成生物膜是根尖周病变治疗失败的主要原因。申请者前期研究发现新基因- - 生物膜形成相关基因（bfrg基因）突变的粪肠球菌，其生物膜形成显著降低，提示bfrg基因与细菌生物膜的形成关系密切，但具体机制尚不清楚。本项目采用Realtime PCR和Western blot等方法探明bfrg基因在生物膜形成过程中的表达状态；应用Knock in和Knock out技术上调或下调bfrg的表达，观察其对生物膜形成的影响；进而利用基因表达谱芯片和免疫共沉淀结合质谱分析技术，筛选其调控的下游分子和相互作用分子，探讨bfrg基因影响细菌生物膜形成的分子机制。通过以上研究，明确bfrg基因在粪肠球菌生物膜形成中发挥的具体作用，阐明其调控生物膜形成的分子机制，以此调控通路的相关分子为重要的药物靶点，阻断其对生物膜形成的正调控作用，为研发新型抗细菌生物膜药物和抑制剂提供新思路。

Multi-species bacterial infection is the key factor in oral infectious diseases. Enterococcus faecalis (E. faecalis) is a prominent pathogen causing root canal treatment failure. The inherent ability of E. faecalis to forming biofilm has made it eradication challenging in endodontically treated teeth. Previous studies have shown that the mutation of bfrg gene lead to dramatic decrease in the amount of biomass of Enterococcus faecalis biofilm. Indicating that bfrg gene plays a role in the biofilm formation of Enterococcus faecalis. But the molecular mechanisms of this process are still unknown. This study will investigate the expression profile of bfrg gene during biofilm formation of Enterococcus faecalis by Realtime PCR and Western blot. Then assess the effects of up or down regulation of bfrg gene expression on the biofilm formation of Enterococcus faecalis by Knock in or Knock out methods. Finally, using Co-Immunoprecipitation method coupled with mass spectrometry technology and gene expression microarray technology, the molecules that interact with BFRG protein will be screened out, and the possible modulation mechanism of bfrg gene on Enterococcus faecalis biofilm formation being analyzed. By these experiments, the relationship between bfrg gene expression and Enterococcus faecalis biofilm formation will be confirmed, and the possible molecular mechanism of bfrg gene on biofilm formation will be elucidated. The findings in this research will provide us new targets or methods to develop novel anti-biofilm bactericidal and inhibitory agents.