中文摘要：

表皮葡萄球菌（Staphylococcus epidermidis,SE）是寄居在人体和黏膜表面的条件致病菌,因可在医疗植入材料表面形成生物膜（biofilm）而具有致病性。细菌双组分信号转导系统可调控生物膜形成,但其调控机制在SE中研究甚少。本课题对arlRS双组分信号转导系统的反应蛋白ArlR在细菌不同生长期的表达情况进行初步研究。首先构建ArlR原核表达质粒,用纯化重组ArlR免疫小鼠,获得多克隆抗-ArlR抗体,免疫Dot方法检测结果显示小鼠抗-ArlR血清效价〉1∶100000。进一步采用蛋白免疫印迹法检测ArlR在SE1457野生株不同生长期中的表达水平,结果显示,ArlR在2h表达量较低,到4h达高峰,6-10h表达量较4h降低。利用反转录实时荧光定量聚合酶链反应检测arlR基因在不同生长期的转录水平,结果显示相应时间点ArlR蛋白表达水平与arlR基因转录水平一致。本研究结果为后期研究双组分信号转导系统arlRS对SE生物膜形成的影响奠定基础。

英文摘要：

Staphylococcus epidermidis （S. epidermidis） is an opportunistic pathogen that colonizes on the surface of human skin and in mucous membranes. It can form biofilms by adhering to indwelling medical devices, often causing biofilm-associated infection. Two-component signal transduction systems （TCSs） play an important role in modulating biofilm formation in bacteria. However, regulation mechanisms of TCSs in S. epidermidis are still poorly understood. In this study, the expression of response regulator ArlR of arlRS TCS in S. epidermidis growth phases was investigated. The prokaryotic expression plasmid pET28a-arlR was constructed, and ArlR protein was expressed and purified. The purified ArlR was used to immunize mice for inducing anti-ArlR antibodies. The titers of anti-ArlR in the immune sera were over 1 ： 100 000, as determined by immune dot blot technique. ArlR expression in the different growth phases in bacteria was detected by Western blot analysis. Results showed that the expression level of ArlR was lowest at 2-hour culture and highest at 4-hour culture, and declined at 6-hour and 10-hour cultures. Western blot analysis results were confirmed by the transcriptional levels of arlR determined by real-time reverse transcriptase- polymerase chain reaction （RT-PCR） analysis. It would help to get additional insight into arlRS TCS regulation functions in the formation of biofilms in S. epidermidis.