Surfactin对蜡样芽孢杆菌芽孢灭活作用途径研究

Study on the inactivation of spores of Bacillus cereus by Surfactin

目的研究Surfactin对蜡样芽孢杆菌芽孢灭活机制。方法将不同浓度Surfactin和芽孢相互作用后,利用紫外分光光度计检测芽孢内大分子组分(如蛋白质、核酸等)的泄漏情况。结果研究发现300和450μg/mL的Surfactin处理后的菌悬液中可明显检测到核酸和蛋白质的泄露。随着时间的延长,加入Surfactin后可使其DNA紫外吸收光谱发生变化,导致DNA最大吸收峰发生红移现象,最初的最大吸收峰253.5 nm移至了257 nm,产生了明显的增色效应。流式细胞的结果说明在最低抑菌浓度(minimal inhibitory concentration,MIC)的情况下,芽孢的膜结构没有明显破损,核内遗传物质没有明显泄露,随着时间延长,泄漏明显;在2~3 MIC浓度的情况下,芽孢的膜结构有明显破损,核内遗传物质有明显泄露。结论Surfactin通过破坏芽孢壁的完整性、与DNA结合对蜡样芽孢杆菌芽孢发挥灭活效应。

Objective To study the mechanism of Surfactin inactivation of Bacillus cereus spores.Methods After the interaction of Surfactin and spores at different concentrations,the leakage of macromolecular components(such as proteins,nucleic acids,etc.)in spores was detected by ultraviolet spectrophotometer.Results The study found that 300 and 450μg/mL Surfactin treatment could clearly detect the leakage of nucleic acids and proteins in the bacterial suspension.With the extension of time,the addition of Surfactin could change the UV absorption spectrum of DNA,resulting in the red shift of the maximum absorption peak of DNA.The initial maximum absorption peak shifted from 253.5 nm to 257 nm,which produced a significant hyperchromic effect.The results of flow cytometry showed that at the minimum inhibitory concentration(MIC),the membrane structure of spores was not significantly damaged,and there was no obvious leakage of genetic material in the nucleus,leakage was significant with the extension of time.Under the condition of 2-3 MIC concentration,the membrane structure of spores was obviously damaged,and the genetic material in the nucleus was obviously leaked.Conclusion Surfacin can inactivate Bacillus cereus spores by destroying the integrity of spore wall and combining with DNA.