中文摘要：

目的：研究和比较人ⅡA型磷脂酶A2（phospholipase A2,PLA2）衍生多肽M17,P26和N1-11对不同细菌在体外的杀菌效应.方法：根据人ⅡA型PLA2氨基酸顺序分别设计合成3个肽分子M17（p51-67）,P26（p99-124）,N1-11（p1-11）.采用琼脂铺板计数法测定杀菌活性,将不同浓度衍生肽分别与革兰阳性菌（G＋）金黄色葡萄球菌、枯草杆菌、屎肠球菌和革兰阴性菌（G-）大肠杆菌、绿脓杆菌、鲍曼不动杆菌在37℃孵育2.5h,然后铺板并置于37℃恒温箱培养18 ～24 h,记录每一琼脂板上的菌落数（CFU）,并计算多肽作用后的杀菌率.结果：ⅡA型PLA2M17对枯草杆菌、金黄色葡萄球菌、屎肠球菌的杀菌回归方程分别为：Y=1.464X＋3.795（ED50 6.65 mg·L-1）,Y=1.152X ＋3.419（ED50 23.57 mg·L-1）,Y 0.836X＋3.832（ED50 24.95mg·L-1）；对大肠杆菌、鲍曼不动杆菌、绿脓杆菌的杀菌回归方程分别为：Y=0.877X＋4.054（ED5012.00 mg·L-1）,Y=1.094X＋3.371 （ED50 30.83 mg·L-1）,Y=1.027X＋3.626（ED5021.77 mg·L-1）;M17肽分子对G＋菌与G-菌均有较强的杀菌活性.P26和N1-11对金黄色葡萄球菌的杀菌回归曲方程分别为：Y=0.915X ＋2.766（ED50276.39 mg·L-1）,Y=1.389X＋1.668（ED50250.52 mg·L-1）,P26和N1-11对大肠杆菌的杀菌回归方程为：Y=1.327X＋1.437（ED50 484.18 mg·L-1）,Y =0.881X ＋2.903（ED50 240.02 mg·L-1）；N1-11和P26对G＋菌有较强的杀菌活性,但对G-菌杀菌活性较弱.M17肽分子对金黄色葡萄球菌的杀菌活性强于P26及N1-11,M17肽分子对大肠杆菌的杀菌活性明显强于P26及N1-11.结论：衍生自人ⅡA型PLA2保守区域17个氨基酸残基的肽M17对G＋菌和G-菌均有较强的杀菌活性,这可能与M17肽分子更易于与细菌结合并发挥作用有关.

英文摘要：

Objective：To study and compare the bactericidal activity of the polypeptide M17,P26 and N1-11 which derives from hunman group Ⅱ A phospholipase A2 （PLA2,phospholipase A2） in vitro.Method：Peptide M 17 （p51-67）,P26 （P99-124）,N1-11 （p1-11） were synthesized according to the sequence of human Group Ⅱ A PLA2 amino acid.Six species of bacterial,Gram positive （G ＋） Staphy 1 ococcus aureus,Bacillus subtilis,Enterococcus faecium,Gram negative （G-） Escherichia coli,Acinetobacter baumannii,Bacillus pyocyaneus,were incubated with different concentration of polypeptides at 37 ℃ for 2.5 hours in a water bath respectively.Then the reaction solution was diluted and agar plates were poured.After 18-24 hours incubation in the thermostated container at 37 ℃.The colony formed units were counted and the bactericida1 rates were calculated.Result：Regression equation of PLA2M17 bactericidal activity on the G＋ bacteria （lococcus aureus,Bacillus subtilis,Enterococcus faecium） were Y =1.464X ＋ 3.795 （ED50 6.65 mg·L-1）,Y =1.152X ＋ 3.419 （ED50 23.57 mg·L-1）,Y =0.836X ＋ 3.832 （ED50 24.95 mg·L-1）.Regression equation of M17 bactericidal activity on the Gbacteria （E.coli,A.baumannii,B.pyocyaneus） were Y =0.877X ＋4.054 （ED50 12.00 mg·L-1）,Y =1.094X＋3.371 （ED50 30.83 mg·L-1）,Y=1.027X＋3.626 （ED50 21.77 mg·L-1）.PLA2M17 possessed potent bactericidal activity on the G ＋ bacteria and G-bacteria.Regression equation of N1-11 and P26 bactericidal activity onB.subtilis were Y=0.915X＋2.766 （ED50 276.39 mg·L-1）,Y=1.389X＋1.668 （ED50 250.52mg·L-1）.Regression equation of N1-11 and P26 bactericidal activity on E.coli were Y =1.327X ＋ 1.437 （ED50484.18 mg·L-1）,Y =0.881X ＋ 2.903 （ED50 240.02 mg·L-1）.N1-11 and P26 possessed strong bactericidal activity of G ＋ bacteria,but weaker activity of G-bacteria.M17 possessed stronger bactericidal activity than N1-11and P26 on B.subtilis and E.coli.Conclusion：Peptide M17 derived from human Ⅱ type A PL