不同动物源抗菌肽对大肠杆菌杀菌机制比较研究

Comparative study on bactericidal mechanism of different animal-derived antibacterial peptides on E. coli

试验旨在对比不同动物源抗菌肽对于大肠杆菌的杀菌机制差异。试验以大肠杆菌为受试菌株,将其与4个浓度梯度的4种抗菌肽孵育30 min后破碎,测量其蛋白质含量;另提取大肠杆菌DNA,分别与不同质量比的抗菌肽孵育30 min后进行凝胶电泳,最后用凝胶成像仪观察;将菌液用不同抗菌肽处理后,分别进行革兰氏染色,于1000倍光镜下观察。结果表明,在蛋白质合成抑制试验中,抗菌肽Magainin与LL-37对于菌体蛋白合成的抑制作用要优于C-BF和Melittin。在DNA结合活性试验中,抗菌肽Magainin在所测浓度范围内没有结合活性,其余3种抗菌肽在质量比为1:2时即表现DNA结合活性。在革兰氏染色试验中,4种抗菌肽均表现出对细胞膜的破坏作用。结果提示,4种动物源抗菌肽的胞内杀菌机制存在差异,但均能破坏细菌细胞膜,胞内作用方面,抗菌肽C-BF与抗菌肽Melittin结合DNA的活性较强,抗菌肽Magainin在蛋白质合成抑制上效果显著,而抗菌肽LL-37对于DNA的结合活性和蛋白质合成抑制均有一定效果。

The study was to compare the bactericidal mechanism of different animal-derived antibacterial peptides against E.coli.In the test,E.coli was used as the test strain.After incubating it with four antibacterial peptides with four concentration gradients for 30 minutes,it was broken and the protein content was measured.In addition,E.coli DNA was extracted and compared with antibacterial peptides with different mass ratios.After incubation for 30 minutes,gel electrophoresis was performed,and finally observed with a gel imager.After the bacterial solution was treated with different antibacterial peptides,they were respectively subjected to gram staining and observed under a 1000×light microscope.The results showed that in the protein synthesis inhibition test,the antibacterial peptides Magainin and LL-37 had better inhibitory effects on bacterial protein synthesis than C-BF and Melittin.In the DNA binding activity test,the antibacterial peptide Magainin did not have binding activity in the concentration range tested,and the remaining three antibacterial peptides exhibited DNA binding activity when the mass ratio was 1:2.In the gram staining test,all four antibacterial peptides showed a disruptive effect on the cell membrane.The results suggest that there are differences in the intracellular bactericidal mechanism of the four animal-derived antibacterial peptides,but they can destroy the bacterial cell membrane.In terms of intracellular effects,the antibacterial peptide C-BF and the antibacterial peptide Melittin have a stronger activity of binding DNA,and the antibacterial peptide Magainin has a significant effect on protein synthesis inhibition,while the antibacterial peptide LL-37 has certain effects on DNA binding activity and protein synthesis inhibition.