纳米氧化锌对金黄色葡萄球菌的抑制及其作用机制研究

Study on the inhibition and mechanism of zinc oxide nanoparticles on Staphylococcus aureus

中文关键词:  纳米氧化锌  金黄色葡萄球菌  抗菌性  细胞形态学  细胞生理学

英文关键词:zinc oxide nanoparticles  Staphylococcus aureus  antibacterial activity  cell morphology  cell physiology

中文摘要:

      目的 研究纳米氧化锌对金黄色葡萄球菌的抑制及其作用机制。方法 统计金黄色葡萄球菌在含有0.5、1.0、1.5、2.0和4.0 mg/mL纳米氧化锌的胰蛋白胨大豆肉汤中的活细胞数目, 不同质量浓度纳米氧化锌处理金黄色葡萄球菌后, 分别采用扫描电镜和透射电镜观察细胞形态和超微结构的变化, 并分析细胞中活性氧(O2-)含量及超氧化物歧化酶(superoxide dismutase, SOD)活性的变化。结果 纳米氧化锌可显著抑制金黄色葡萄球菌的生长(P<0.05), 当纳米氧化锌的质量浓度为2.0 mg/mL时, 培养24 h后金黄色葡萄球菌的数目比不加纳米氧化锌的对照组低5.2 logCFU/mL (P<0.05)。经纳米材料处理后, 金黄色葡萄球菌的菌体外形虽然未发生明显改变, 但细胞内部的组织结构遭受严重损伤, 细胞膜结构模糊, 胞内的O2-含量显著升高(P<0.05), SOD酶活性在处理后期显著降低(P<0.05)。结论 纳米氧化锌的处理可使金黄色葡萄球菌菌体细胞组织结构和细胞膜发生损伤, 并导致细胞产生了氧化应激反应, 从而抑制其增殖。

英文摘要:

      Objective To study the inhibitory effect of zinc oxide nanoparticles on Staphylococcus aureus and its mechanism. Methods The numbers of viable cells of S. aureus in trypticase soy broth containing 0.5, 1.0, 1.5, 2.0 and 4.0 mg/mL zinc oxide nanoparticles were calculated, the cellular morphology and ultrastructure of S. aureu were observed by scanning electron microscope and transmission electron microscope respectively, meanwhile, the reactive oxygen (O2-) content and the superoxide dismutase (SOD) activities were determined after S. aureus cells were treated with zinc oxide nanoparticles in different mass concentrations. Results Zinc oxide nanoparticles could significantly inhibit the growth of S. aureus (P<0.05), the number of S. aureus resulted a 5.2 logCFU/mL reduction compared to the non-nanoparticles added control group after 24 h of cultivation (P<0.05) when the mass concentration of zinc oxide nanoparticles was 2.0 mg/mL. Although the cell shape did not show a significant change, the inner structure was seriously damaged, and the cell membrane became obscure after treated with zinc oxide nanoparticles, the inner O2- content increased obviously (P<0.05), while the SOD activity declined significantly during the late treatment of zinc oxide nanoparticles (P<0.05). Conclusion The treatment of zinc oxide nanoparticles can cause the injury on the cell structure and membrane, and lead to cellular oxidative stress response, which should contribute to the inhibition of the proliferation of S. aureus.