目的 研究分离自药用植物白毛蛇Humata tyermanni的内生真菌链格孢菌发酵产物醋酸乙酯提取物（B06_e）对金黄色葡萄球菌细胞膜完整性和通透性的影响。方法 采用二倍稀释法测定B06_e对金黄色葡萄球菌的最小抑菌浓度（MIC）；测定B06_e作用前后金黄色葡萄球菌培养液电导率，206、280 nm处吸光度（A）值的变化并结合流式细胞术研究B06_e作用前后细胞膜通透性的变化。利用扫描电子显微镜（SEM）及傅里叶红外变换光谱（FT-IR）研究B06_e对细胞膜结构的影响。结果 B06_e对金黄色葡萄球菌的MIC为50 μg/mL。3×MIC处理组的电导率是对照组的1.06倍；经B06_e处理后，反应液的A₂₆₀和A₂₈₀值均显著高于对照组；3×MIC处理组的β-半乳糖苷酶活性是对照组的9.43倍；流式细胞仪分析表明3×MIC处理组被碘化丙啶（PI）着染的阳性细胞比例是对照组的47.63倍；SEM和FT-IR分析结果显示，B06_e处理后，菌体细胞结构发生了损伤。结论 B06_e能增强金黄色葡萄球菌细胞膜的通透性，破坏细胞膜的完整性，造成外源物质的大量流入和细胞质的大量外泄，从而使得菌体细胞内渗透压和代谢调控紊乱，最终导致细菌丧失生长繁殖的能力。

Objective To investigate the effect of ethyl acetate extract (B06_e) from fermentation liquid of an endophytic fungus Alternaria spp. on the cell membrane integrity and the permeability of Staphylococcus aureus.Methods The minimum inhibitory concentration (MIC) of B06_e against S. aureus was measured by double dilution method; The changes of electric conductivity of bacterial culture, A₂₆₀ and A₂₈₀ before and after treated by B06_e were analyzed, respectively. Besides, the changes of cell membrane permeability before and after by B06_e was measured by flow cytometry. The effect of B06_e on the cell membrane structure was investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR).Results The results showed that MIC value of B06_e against S. aureus was 50 μg/mL. The conductivity of 3×MIC treatment group was 1.06 times of the value of the control group; after treatment of B06_e, the values of A₂₆₀ and A₂₈₀ were significantly higher than those of the control group:The beta-galactosidase activity of 3×MIC treatment group was 9.43 times more than the value of the control group; Flow cytometry analysis showed that 3×MIC treatment group by propidium iodide (PI) staining of positive cells was 47.63 times more than the control group; SEM and FT-IR analysis showed that the structure of bacterial cell changed after B06_e treatment.Conclusion B06_e can kill S. aureus cell by increasing the permeability of its cell membrane and destroy cell membrane integrity.

国家自然科学基金项目资助（31460032；81660581）