姜黄素光动力技术对食源性致病菌抗氧化酶体系的影响研究

Effect of curcumin-based photodynamic technology on antioxidant enzyme of foodborne pathogenic bacteria

新型非热光动力技术以产生活性氧(reactive oxygen species,ROS)的方式有效灭活食源致病菌,然而其对不同细菌的杀菌机制尚不清晰。文章以大肠杆菌(Escherichia coli)O157:H7 ATCC 700728和金黄色葡萄球菌(Staphylococcus aureus)ATCC 6538为研究对象,借助聚合酶链式反应(polymerase chain reaction,PCR)、蛋白质印迹法(Western Blot)、酶活力检测等方法,解析以姜黄素为光敏剂的光动力技术对细菌抗氧化酶体系的影响,明确其对不同革兰氏细菌杀菌机制的区别。结果表明:2种细菌的抗氧化酶活力随着姜黄素浓度的升高而降低;经光动力处理后,除超氧化物歧化酶(SOD)外,大肠杆菌抗氧化酶体系相关基因和蛋白的表达水平差异不大,然而金黄色葡萄球菌相关基因和蛋白的表达水平却呈现显著降低。研究表明,活性氧诱导细菌内环境的紊乱,降低其抗氧化能力是导致其死亡的直接原因之一,并且金黄色葡萄球菌比大肠杆菌对光动力技术更为敏感。

The new non-thermal photodynamic technology effectively inactivates foodborne pathogens by generating reactive oxygen species(ROS).However,the sterilization mechanism on different bacteria is still unclear.In this paper,Escherichia coli O157:H7 ATCC 700728 and Staphylococcus aureus ATCC 6538 were used as research objects.By the detection of polymerase chain reaction(PCR),Western Blot,and enzyme activities,the effects of curcumin-based photodynamic technology on the bacterial antioxidant enzyme system were analyzed,and the differences of the germicidal mechanisms between diverse bacteria were identified.The results showed that the antioxidant enzyme activities of the two bacteria decreased with increasing curcumin concentration.After photodynamic treatment,the differences of expression levels of genes and proteins related to the antioxidant enzyme of E.coli were nonsignificant except superoxide dismutase(SOD).But the expression levels of the S.aureus-related genes and proteins were remarkably reduced.Studies have shown that ROS induces disturbances in the internal environment of bacteria,then reducing its antioxidant capacity,which is one of the direct reasons of death.Moreover,S.aureus is more sensitive than E.coli to photodynamic technology.