不同动物源抗菌肽对沙门氏菌杀菌机制比较研究

Comparative study on bactericidal mechanism of different animal-derived antibacterial peptides on Salmonella

研究旨在比较4种动物源抗菌肽对沙门氏菌的杀菌机制差异。试验将浓度分别为0、1/2MIC、MIC和2MIC的抗菌肽与试验菌株猪霍乱沙门氏菌、肠炎沙门氏菌共同孵育,破碎后测定该2种血清型沙门氏菌的蛋白质含量。利用DNA提取试剂盒提取细菌DNA,依照抗菌肽与DNA质量比为1∶2、1∶1、2∶1、4∶1与试验菌株孵育,通过凝胶成像仪观察DNA条带结果。对经过不同抗菌肽处理的菌液,进行革兰氏染色,在油镜下观察细菌形态结构,拍照记录。结果显示,抗菌肽Magainin对菌体蛋白合成的抑制作用优于Melittin和C-BF,LL-37的蛋白合成抑制作用最弱。抗菌肽Magainin在所测浓度范围内无结合活性,其余3种抗菌肽在质量比为2∶1时,能够完全抑制DNA迁移。在细菌形态影响试验中,4种抗菌肽均表现出对细胞膜的破坏作用。试验表明,4种动物源抗菌肽除Magainin外,对细菌蛋白和DNA合成均有不同程度抑制作用,4种抗菌肽均可以通过破膜机制行使杀菌功能。

The study was to compare the bactericidal mechanisms of four animal-derived antimicrobial peptides against Salmonella.In the experiment,antimicrobial peptides at concentrations of 0,1/2MIC,MIC,and 2MIC were co-incubated with the test strains Salmonella choleraesuis and Salmonella enteritidis,and the protein contents of the two serotypes of Salmonella were determined after breaking.Bacterial DNA was extracted by DNA extraction kit.After incubation with antimicrobial peptides and DNA mass ratios of 1∶2,1∶1,2∶1 and 4∶1,the DNA bands were observed by gel imager.The bacterial liquid treated with different antimicrobial peptides was stained by gram staining,and taken photos after observing the morphological structure of the bacteria under the oil mirror.The results showed that the antimicrobial peptide Magainin had better inhibitory effect on protein synthesis than Melittin and C-BF,while LL-37 had the weakest inhibitory effect on protein synthesis.Magainin had no binding activity in the measured concentration range,and the other three peptides could completely inhibit DNA migration when the mass ratio was 2∶1.In the experiment of bacterial morphology influence,all the antibacterial peptides showed the destruction of cell membrane.The results indicates that all the four animal-derived antimicrobial peptides except Magainin had different inhibitory effects on bacterial protein and DNA synthesis,and all the four antibacterial peptides could perform bactericidal functions through membrane breaking mechanism.