桃柁酚对金黄色葡萄球菌生物膜形成及cidA表达的影响

Effects of totarol on cidA expression and biofilm formation by Staphylococcus aureus

为研究桃柁酚对金黄色葡萄球菌(S.aureus)生物膜形成的影响及其机制,本研究通过结晶紫半定量法和激光共聚焦显微镜检测桃柁酚对S.aureus生物膜形成的影响,利用实时定量RT-PCR分析桃柁酚对cidA及其调控基因的作用,并测定了桃柁酚对胞外DNA(eDNA)释放的作用及对HaCaT细胞的细胞毒性。结果表明,桃柁酚可以有效减少eDNA的释放并抑制S.aureus生物膜的形成,并且抑制趋势呈剂量依赖关系。此外,在1/8×MIC药物浓度时,桃柁酚可以诱导eDNA的释放并诱导生物膜形成。桃柁酚可以通过影响agr和sar调控系统,作用于cidA基因进而影响eDNA释放及生物被膜的形成。而且,4×MIC浓度的桃柁酚对人体无毒害作用。本研究为治疗S.aureus感染提供新的方法,并为进一步研究桃柁酚的作用机制奠定了基础。

To evaluate the effects of totarol on biofilm formation by Staphylococcus aureus, the amount of biofilms and extmcellular DNA （eDNA） were quantified by spectrophotometer. Real-time RT-PCR analysis was performed to detect the expression of the biofilm-related genes. The effects of totarol on S.aureus biofilm were observed by confocal laser microscopy （CLSM）. The toxicity of totarol to HaCaT cells was tested by using a CCK-8-based method. Results showed that eDNA release and biofilm formation by S.aureus effectively inhibited by toratol in a dose-dependent way, and remarkably, eDNA release and biofilm formation were induced when toratol was used at 0.125 p,g/mL. Real-time RT-PCR analysis revealed that totarol was able to impact agrA, sarA and cidA gene expression, eDNA release and biofilm formation. However, the metabolic activity of HaCaT cells was not reducted by the cell viability assay. Therefore, the totarol was an effective antimierobial agent to combat S.aureus biofilms and the present study would lay a foundation for further studies.