抗菌肽JH-3的抑菌活性及其稳定性分析

Analysis of Antimicrobial Activity and Stability of Antibacterial Peptide JH-3

对牛血红蛋白源抗菌肽P3进行氨基酸改造,并了解改造后抗菌肽JH-3的抑菌活性和稳定性。通过微量稀释法检测了抗菌肽JH-3的最小抑菌浓度（MIC）,通过扫描电镜观察了细菌和真菌形态的变化,测定了抗菌肽JH-3的溶血性、热稳定性、酸碱稳定性和盐稳定性。结果表明：抗菌肽JH-3对革兰阳性菌（金黄色葡萄球菌、猪链球菌2型）的MIC为6.25-25μg·mL^-1,对革兰阴性菌（大肠杆菌、猪霍乱沙门菌、副猪嗜血杆菌、胸膜肺炎放线杆菌）的MIC为3.125-50μg·mL^-1,对真菌（白色念珠菌）的MIC为12.5μg·mL^-1,均具有良好的抗菌活性。经抗菌肽JH-3处理后,大肠杆菌细胞表面出现皱缩、孔洞;金黄色葡萄球菌出现菌体皱缩,细胞的完整性受到破坏;白色念珠菌细胞表面出现凹陷、突出、裂痕。在6-100倍MIC时312.5μg·mL^-1抗菌肽JH-3的溶血率仅12.84%;75-100℃的高温、80-100mmol·L^-1的高浓度NaCl和pH 4.0及pH 10.0的高酸碱性对抗菌肽JH-3的抑菌活性没有明显的影响。研究结果为抗菌肽JH-3的临床应用提供了理论基础,且抗菌肽JH-3有替代抗生素成为新抗菌药物的潜力。

The aim of the present study was to modify antimicrobial peptide P3 from bovine hemoglobin on amino acid,and to know the antibacterial activity and stability of the antibacterial peptide JH-3modified based on P3.The minimum inhibitory concentrations（MIC）of JH-3against several bacteria were detected with the method of serial dilution.The morphology changes of bacterial and fungus were observed by scanning electron microscope（SEM）.The hemolytic activity,thermal stability,acid base stability and salt stability of the antibacterial peptide JH-3were determined.The results showed that the MIC of JH-3against gram positive bacteria（Staphylococcus aureus,Streptococcus suis 2type）was between 6.25-25μg·mL^-1.The MIC against Gram negative bacteria（Escherichia coli,Salmonella choleraesuis,Haemophilus parasuis,Actinobacillus pleuropneumoniae）was between 3.125-50μg·mL^-1.The MIC against fugus（Monilia albicans）was 12.5μg·mL^-1.Shrinkage and holes appeared on the surface of treated E.coli cells.Shrinkage and incomplement presented on the cell surface of S.Aureus.And M.albicanshowed sunken,protruding and crack.Hemolytic rate of JH-3was only 12.84% at 312.5μg·mL-1（6-100timesMIC）.At the condition of 75-100 ℃,80-100mmol·L^-1 NaCl,pH 4and pH 10,the antimicrobial activity of JH-3was not changed significantly.These findings provided theoretical basis for the clinical application of antimicrobial peptide JH-3,and antibacterial peptide JH-3has the potential as the new antibacterial drugs instead of antibiotics.