氧化锌纳米颗粒对大肠杆菌的毒性效应及机制

以大肠杆菌为研究对象,通过检测纳米氧化锌暴露下大肠杆菌的生长、胞内活性氧簇(ROS)水平以及酶活性的变化,研究了纳米氧化锌对大肠杆菌的毒性效应以及可能的毒性机制。结果表明,纳米氧化锌能够抑制大肠杆菌的细胞生长;纳米氧化锌浓度越高,对大肠杆菌的抑制作用越大,其半效应浓度(EC50)为251 mg/L。在纳米氧化锌暴露下的大肠杆菌的细胞中ROS随着暴露时间的增加而升高,而细胞内过氧化氢酶(CAT)活性、超氧化物歧化酶(SOD)活性以及总抗氧化能力(T-AOC)均显著升高。这说明氧化损伤是纳米氧化锌的重要毒性机制,同时大肠杆菌能够通过提高酶活性对纳米ZnO暴露做出应激的反应以减轻其对细胞造成的伤害。

Toxicity Effects and Mechanism of ZnO Nanoparticles on Escherichia coli

Toxicity effects and mechanism of ZnO NPs on Escherichia coli were studied. Experiments were carried out to study the inhibitive effect of ZnO NPs on E. coli growth. E. coli were exposed to ZnO NPs for 2 h, the intracellular reactive oxygen species （ROS） and antioxi- dant enzyme activities were determined. The toxicity results showed that ZnO NPs could inhibit the growth of E. coli in liquid LB medium （ECso = 251 rag/L）. Besides, intracellular ROS of E. coli treated with ZnO NPs increased with the prolongation of exposhre. Moreover, the activities of catalase （CAT）, superoxide dismutase （SOD）, total antioxidant capacity （T-AOC） were significantly increased. These results demonstrated that oxidative damage was the important mechanism of ZnO toxicity to E. coli. And E. coli can improve the enzyme activity to re- duce the damage of ZnO NPs to some degree.