小球藻兔防御素NP-1抗菌机制初探  

Study on antibacterial mechanism of rabbit defensin NP-1 expressed by Chlorella

作　　者：田新利[1,2] 王新[1] 胡天驹[1] 白丽莉[3] 张浩[1] 陈宇红[3] 朱萌[1] 赵朕龙[1] 高萌[1] 徐超[1] 胡赞民[3] 彭宜红[1] 

机构地区：[1]北京大学基础医学院病原生物学系,100191 [2]邢台医学高等专科学校微生物学和免疫学教研室,054000 [3]中国科学院遗传与发育生物学研究所分子农业研究中心

出　　处：《中华微生物学和免疫学杂志》2013年第10期756-760,共5页Chinese Journal of Microbiology and Immunology

基　　金：国家科技支撑计划项目(2013BAD10B03-3)；中国科学院项目(KSZD-EW-Z-021-3-2)；国家自然科学基金国家基础科学人才培养基金

摘　　要：目的：初步探讨小球藻表达的兔防御素NP-1的抗菌机制。方法通过液体培养抑制测定法、阳离子中和试验和扫描电镜技术，分别测定小球藻表达的兔防御素NP-1对临床分离的1株耐甲氧西林金黄色葡萄球菌（ MRSA）和1株多重耐药铜绿假单胞菌（ MDR-PA）的抑菌动力学作用、明确正电荷在NP-1抗菌作用中的重要性，以及NP-1对细菌形态结构的影响。结果小球藻表达的兔防御素NP-1对MRSA和MDR-PA的抑菌率在3 h达到80％以上，其中对MRSA的抗菌作用具有浓度依赖性；带有正电荷的精氨酸（0．25％～0．50％）能有效抑制NP-1的抗菌作用；此外，扫描电镜观察到NP-1可分别导致菌体出现孔洞（ MRSA）或变形塌陷（ MDR-PA）。结论小球藻兔防御素NP-1对耐药的革兰阳性菌和革兰阴性菌均有良好的抗菌作用；一定浓度的精氨酸能够竞争性抑制NP-1的抗菌作用；NP-1对MRSA的抗菌机制可能属于“孔洞”学说。Objective To investigate antibacterial mechanism of rabbit defensin NP-1 expressed by Chlorella.Methods Liquid culture inhibition assay was used for detecting antibacterial effects of rabbit defensin NP-1 on a methicillin-resistant Staphylococcus aureus （MRSA） isolate and one strain of multidrug resistant Pseudomonas aeruginosa （ MDR-PA） .The cation neutralization test was applied to analyze effects of positive charges on the antibacterial activity of NP-1.The scanning electron microscopy was used to observe bacterial morphological structures of MRSA and MDR-PA with NP-1 intervention .Results The antibacteri-al rates of NP-1 against MRSA and MDR-PA reached up to 80%after three hours of intervention .The anti-bacterial activity of NP-1 against MRSA was in a dose-dependent manner .Competitive inhibition assay dem-onstrated that positively charged arginine , with concentrations ranging from 0.25%to 0.50%, could effec-tively inhibit antibacterial activities of NP-1.The scanning electron microscopy showed that NP-1 could in-duce holes on the membrane of MRSA , and deformation or collapse of MDR-PA.Conclusion The rabbit defensin NP-1 expressed by Chlorella has strong antibacterial effects on drug-resistant gram-positive bacteria and gram-negative bacteria , which could be competitively inhibited by a certain concentration of arginine . The antibacterial mechanism of NP-1against MRSA might be related to the pore-forming process.

关 键 词：NP-1 抗菌机制 MRSA MDR—PA 

分 类 号：R96[医药卫生—药理学]