蝇蛆抗菌肽的抑菌活性及其理化特性的探究

摘要

In order to obtain high an tibacterial activity of Musca domestica antibacterial peptide and apply it as a substitute for antibiotics in animal husbandry industry,the higher antibacterial activity components of antibacterial peptides from Musca domestica larvae were purified from antibacterial peptides crude extract by Sephadex G-25 and G-50 gel filtration chromatography.Determining its antibacterial activity, thermal stability , repeated freezing and thawing stability and the effect of pH on antibacterial activity . The results showed that antibacterial peptides crudes extracted from Musca domestica larvae had marked inhibition effect to escherichia coli, staphylococcus aureus and salmonellas.Identifing purified antibacterial peptides' molecular weight obtained by SDS-PAGE was about 10kD.The determination results of physical and chemical characteristics of antibacterial peptides showed that antibacterial peptides from Musca domestica larvae had a good thermal stability.When the time of repeated freezing and thawing was less than 8, antibacterial activity of antibacterial peptides from Musca domestica had no significant differences.While freezing and thawing times was more than 8,it still had antibacterial activity but decrease. When pH was from 4.0 to 9.0, its antibacterial activities exist no obvious differences (P>0.05).While pH was up to 10.0 ,its antibacterial activity decreases significantly. There was a difference to antibacterial peptides'antibacterial activity, when pH was beyond a certain value.The study provided the basic data for antibacterial peptides from Musca domestica larvae as safe antibiotics were applied to futher development and utilization of animal husbandry industry.%为了获得具有较高抑菌活性的蝇蛆抗菌肽，并将其作为抗生素替代品应用于畜牧养殖业，本研究通过G-25和G-50凝胶柱层析对蝇蛆抗菌肽粗提液进行纯化得到抗菌活性较高蝇蛆抗菌肽组分，测定其抑菌活性的同时开展其热稳定性、反复冻融稳定性及不同 pH 对其活性影响研究。结果显示：蝇蛆抗菌肽粗提液对大肠杆菌、金黄色葡萄球菌、沙门氏菌均有显著的抑制作用；利用SDS-PAGE技术，鉴定纯化的蝇蛆抗菌肽的蛋白质分子量约为10 kD；蝇蛆抗菌肽具有较好的热稳定性；反复冻融对其抗菌活性的影响无显著差异，超过8次后抑菌活性受到抑制，但仍具有抑菌活性；用不同pH作用蝇蛆抗菌肽测定其酸碱稳定性，当pH为4.0—9.0的范围内，蝇蛆抗菌肽的抑菌活性间差异不显著（P＞0.05），pH达到10.0时，抑菌活性明显降低，说明强碱性条件会影响蝇蛆抗菌肽的抑菌活性。本研究对蝇蛆抗菌肽作为绿色抗生素替代品用于畜牧养殖业的进一步开发与利用提供了科学依据。