中文摘要：

目的利用反义RNA技术下调菌体内p日旭的表达水平，考察parE基因下调对大肠埃希菌生长以及新生霉素敏感性的影响。方法应用反义RNA基因沉默技术，首先构建靶NparE的反义RNA菌株，下调parE基因的表达；然后过表达回补parE基因，根据生长表型判断parE基因对菌体生长以及药物敏感性的影响，通过FIC指数测定进一步判断parE基因沉默与新生霉素药物敏感性的相关性。结果构建了一株反义RNA菌株E．coliDH5α／pHNparE，其生长速率跟反义诱导剂PTG浓度呈反比，且对新生霉素药物敏感性增加，而对其他药物敏感性无变化；回补的parE基因能够缓解菌体生长受抑制现象，并对新生霉素的敏感性降低，部分抑菌浓度指数（FICI）小于0．5，表明反义菌株的沉默与新生霉素之间具有协同作用。结论E.coli中parE基因的下调会抑制菌体的生长，并增加菌体对新生霉素的药物敏感性。

英文摘要：

Objective To investigate the effect of antisense RNA mediated parE gene downregulation on bacterial growth and sensitivity to novobiocin of Escherichia coli. Methods Antisense RNA strain with specific parE gene downregulation was constructed based on antisense RNA technology, and then the silenced gene was complementated by gene-over expression. Gene silencing efficacy on bacterial growth and drug sensitivity was investigated by assessing cell growth. Then the correlation between parE silencing and novobiocin was complementated by fractional inhibitory concentration indices （FICIs） calculations. Results We constructed a strain of E.coli DH5α/pHNparE which can express antisense RNA of parE. Its growth rate was reducing with the increasing concentration of inducing agent, IPTG. Suppressing of the parE expression does not sensitize E.coli DH5α/pHNparE strain to PEA, FOS and TMP except novobiocin. The complementation of parE gene lead to a rescue of cell growth and low sensitivity to novobiocin treatment. Furthermore, fractional inhibitory concentration index （FICI〈0.5） showed a high level of synergy between parE silencing and novobiocin. Conclusion The downregulation of parE in E.coli resulted in bacterial growth retardation and sensitization to novobiocin.