猪β-防御素体外抗菌活性和抗氧化活性研究  

In vitro Detections of Antimicrobial and Antioxidant Activities of Porcine β-defensins

作　　者：薛现凤[1] 韩菲菲[1] 高彦华[1] 刘倚帆[1] 夏溪[1] 汪以真[1] 

机构地区：[1]浙江大学饲料科学研究所,浙江省饲料与动物营养重点实验室,农业部华东动物营养与饲料科学重点实验室,杭州310058

出　　处：《农业生物技术学报》2012年第11期1291-1299,共9页Journal of Agricultural Biotechnology

基　　金：国家杰出青年基金(No.31025027);中国博士后科学基金第五批特别资助项目(No.2012T50528)

摘　　要：抗菌肽在哺乳动物先天免疫系统中发挥着非常关键的作用。猪β-防御素1（pBD-1）和β-防御素2（pBD-2）是猪体内两种重要的抗菌肽。本研究采用化学方法合成pBD-1和pBD-2，通过改良的微量肉汤稀释法研究了pBD-1和pBD-2对8种革兰氏阴性菌和3种革兰氏阳性菌的抗菌活性，并利用透射电镜初步探究了pBD-1和pBD-2可能的杀菌机制；本研究还进-步探讨了pBD-1和pBD．2的体外抗氧化活性。抗菌试验结果表明，pBD-1对EscherichiacoliEPEC078：K80和Bacillus subtilis ATCC6633具有较好的抑菌活性，最小抑菌浓度（MtC）均为32μg／mL，最小杀菌浓度（MBC）分别为32μg／mL和128μg／mL;pBD．2仅对Pseudomonas．aeruginosaCMCC10104有较好的抗菌活性，MIC为8twdmL，MBC为32μg／mL，对其他细菌抗菌活性较弱；透射电镜观察结果表明，pBD-1和pBD-2能够作用于菌体细胞膜杀灭细菌；抗氧化活性实验结果表明，pBD-1和pBD-2在0-256μg／mL范围内，具有清除自由基的功能和还原力，且呈现浓度依赖效应。研究结果揭示，pBD-1和pBD-2对特定细菌发挥抗菌作用的同时，还具有-定的抗氧化活性，为进-步阐明pBD-1和pBD-2的生物学功能及其开发和应用提供了基础资料。Defensins are antimicrobial peptides which play important roles in the innate immune system of mammals. β-defensin-1 （pBD-1） and β-defensin-2（pBD-2） are two defensins of great importance in swine. The information on defensin activity and function is very scarce. To study their antimicrobial and antioxidant activities, pBD-1 and pBD-2 were chemically synthesized, and their antirnicrobial activities against eight gram-negative bacteria and three gram-positive bacteria were determined by minimal inhibitory concentration （MIC）. The mechanisms of antimicrobial peptide activity were preliminary inquiried by transmission electron microscope, and the antioxidant activities in vitro were also studied. The results showed that pBD-1 had strong inhibition against Escherichia coli EPEC O78：K80 and Bacillus subtilis ATCC 6633, which MIC were both 32 μg/mL and minimal bactericide concentration（MBC） were 32 μg/mL and 128 μg/mL, respectively. But pBD-2 had strong inhibition just against Pseudomonas.aeruginosa CMCC 10104, which MIC was 8 μg/mL and MBC was 32 μg/mL. Transmission electron microscopy results showed that pBD-1 and pBD-2 might kill bacteria through the formation of transmembrane pore. pBD-1 and pBD-2 showed radicals scavenging activities and reducing power. Furthermore, the antioxidative activities of them were stronger when the concentrations were higher within certain concentration ranges. In conclusion, the research results indicated that pBD-1 and pBD-2 not only had antimicrobial activities but also had antioxidant activities in certain extent, and this may provide data base to clarify their biological functions and their development and application in animal husbandry.

关 键 词：猪 防御素 抗菌活性 抗氧化 

分 类 号：S859.796[农业科学—临床兽医学]