乳酸链球菌素对肉食杆菌和腐生葡萄球菌的抑菌机制研究

Study on the antibacterial mechanism of Nisin against Carnivorous bacteria and Saprophytic staphylococcus

中文关键词:  乳酸链球菌素  肉食杆菌  腐生葡萄球菌  抑菌机制

英文关键词:Nisin  Carbibacterium divergens  Staphylococcus saprophyticus  antibacterial mechanism

中文摘要:

      目的 研究乳酸链球菌素(Nisin)对肉食杆菌(Carbibacterium divergens)和腐生葡萄球菌(Staphylococcus saprophyticus)的抑菌作用机制。方法 采用肉汤稀释法测定乳酸链球菌素对肉食杆菌和腐生葡萄球菌的最小抑菌浓度(minimal inhibitory concentration, MIC), 由细菌生长曲线、电导率、胞外核酸、胞外蛋白、碱性磷酸酶(alkaline phosphatase, AKP)活力, 并采用扫描电子显微镜(scanning electron microscope, SEM)观察, 综合评价乳酸链球菌素对肉食杆菌和腐生葡萄球菌细胞结构的影响, 通过测定细胞保护酶中的超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)活力来分析乳酸链球菌素对肉食杆菌和腐生葡萄球菌细胞酶活性影响。结果 乳酸链球菌素对肉食杆菌和腐生葡萄球菌的MIC分别为6.2500 mg/mL和10.000 mg/mL, 菌体经MIC和2 MIC处理后, 其正常生长受到抑制, 其对肉食杆菌的抑菌作用明显强于腐生葡萄球菌被抑制的作用。SEM观察发现, 经MIC乳酸链球菌素处理后的两种菌体细胞形态发生扭曲收缩、有褶皱, 电导率、胞外核酸、胞外蛋白含量和AKP活力升高, 而菌体的SOD与CAT活力均降低。结论 乳酸链球菌素能够改变肉食杆菌和腐生葡萄球菌细胞的形态、增加膜的通透性, 造成了细胞内容物的泄露, 降低菌体内细胞保护酶的作用, 从而导致细菌的死亡, 乳酸链球菌素对肉食杆菌的抑制作用强于对腐生葡萄球菌。

英文摘要:

      Objective To study the antibacterial mechanism of Nisin against Carbibacterium divergens and Staphylococcus saprophyticus. Methods The broth dilution method was used to determine the minimum inhibitory concentration (MIC) of Nisin against Carbibacterium divergens and Staphylococcus saprophyticus, the effects of Nisin on the cell structure of Carbibacterium divergens and Staphylococcus saprophyticus were comprehensively evaluated by bacterial growth curve, electrical conductivity, extracellular nucleic acid, extracellular protein, alkaline phosphatase (AKP) activity, and scanning electron microscope (SEM) was used to observe and comprehensively evaluate the effects of Nisin on the cell structures of Carbibacterium divergens and Staphylococcus saprophyticus. The cellular enzymatic activity of Nisin against Carbibacterium divergens and Staphylococcus saprophyticus was analyzed by measuring the activity of superoxide dismutase (SOD) and catalase (CAT) among cytoprotective enzymes. Results The MICs of Nisin against Carbibacterium divergens and Staphylococcus saprophyticus were 6.2500 mg/mL and 10.000 mg/mL, respectively. After MIC and 2 MIC treatment, the normal growth of the bacteria was inhibited, and its antibacterial effect on Carbibacterium divergens was significantly stronger than that of Staphylococcus saprophyticus. Through SEM observation, it was found that the cell morphogenesis of 2 kinds of bacteria after treatment with MIC Nisin was twisted, shrunk and wrinkled. The electrical conductivity, extracellular nucleic acid, extracellular protein content, and AKP activity increased, while the SOD and CAT activities of the bacteria decreased. Conclusion Nisin can alter the morphology of cells in Carbibacterium divergens and Staphylococcus saprophyticus, increase membrane permeability, cause leakage of cell content, reduce the role of cell protective enzymes in the cell, and ultimately lead to bacterial death. Nisin has a stronger inhibitory effect on Carbibacterium divergens than on Staphylococcus saprophyticus.