紫外线对大肠杆菌的损伤机制研究

Mechanism of Escherichia coli injury under UV disinfection

目的观察紫外线消毒对水中大肠杆菌(E.coli)的损伤情况及其损伤机制。方法选择E.coli ATCC25922为实验菌,用平板计数法研究不同紫外线照射剂量下E.coli的灭活率及损伤情况,用拉曼光谱和透射电子显微镜分别观察紫外线消毒后该菌的膜通透性和细胞形态的变化。结果紫外线消毒后E.coli细胞膜通透性增加4.87倍,拉曼光谱测量显示损伤状态的该菌存在蛋白质、脂质及糖类的结构变化,透射电镜观察显示损伤状态的E.coli质壁出现一定程度的分离。结论紫外线消毒对E.coli的损伤表现在蛋白质、核酸、糖类等多种生物活性分子的不同程度损伤,而不是某种结构的单一损伤。

Objective To study the inactivation kinetics and injury mechanism of Escherichia coli under UV disinfection in drinking water.Methods The inactivation kinetics of E.coli ATCC 25922 was determined by plate count methods in the UV disinfection experiment.The morphology,cell membrane permeabilization and injury of biological macromolecules were observed under a transmission electron microscope （TEM）.The rate of ONPG hydrolysis and changes in activities of antioxidant enzymes were observed Raman spectroscopy.Results the changes of damaged cells involved morphological damage such as loss of the structural integrity of the wall and membrane,condensation of cellular material and leakage of significant amounts of cytoplasmic material,a more than four-fold increase of cell membrane permeabilization and damage to the structure of protein,nucleic acids and phospholipid.Conclusion UV disinfection can lead to a multi-target damage.