家蝇幼虫血淋巴中抗真菌肽的诱导方法比较及抗真菌活性

以未诱导组作为空白对照研究比较真菌诱导、超声诱导和热诱导家蝇Musca domestica 幼虫血淋巴初提液的抗真菌肽效果，比较各种诱导方法诱导后的幼虫存活率；用凝胶层析法和高效液相分离纯化热诱导家蝇3龄幼虫抗真菌肽，检测其抗白假丝酵母菌Candida albicans和新生隐球菌Cryptococcus neoformans活性；SDS-PAGE分析抗真菌肽的蛋白分子量范围。结果表明：3种诱导方法诱导后家蝇幼虫均产生具有明显抗真菌作用的抗真菌肽，其初提液抑菌圈大小没有明显差别；真菌诱导组和热诱导组幼虫存活率低于对照组，而超声诱导组与对照组相比则无明显差别。经分离纯化后，抗真菌肽仍具有较好的抗真菌活性；SDS-PAGE分析表明该抗真菌肽有效成分的蛋白分子量在14.4 kD以下。结果提示热诱导家蝇幼虫产生抗真菌肽是一种方便、有效的诱导方式。

Effect of different inducible agents on antifungal peptides of housefly larvae and their antifungal activity

Expression of antifungal peptides from hemolymph of housefly larvae was studied after fungal, thermal and ultrasonic induction, and the survival rates of the larvae were compared between different induction treatments. The peptides were isolated with Sephadex G-50 filtration and HPLC, and their antifungal activity and molecular weight were detected. The results showed that the antifungal peptides in the hemolymph of larvae under three different induction treatments all had obvious antifungal activity to Candida albicans (strain 09) and Cryptococcus neoformans. The survival rates of the larvae of the fungal and thermal induction treatments were obviously lower than that of the control, while that of the ultrasonic induction treatment was not obviously different from that of the control. The antifungal peptide purified from the peptides obtained by the thermal induction still showed high antifungal activity, with its molecular weight less than 14.4 kD. The results suggested that thermal induction was an easy and efficient method to induce antifungal peptides in housefly.