黄粉虫幼虫小分子量抗菌肽的分离纯化

Isolation and purification of small antimicrobial peptide from larvae of mealworm,Tenebrio molitor

昆虫抗菌肽具有良好的抑菌效果,有望开发成新一代抗生素。本文以金黄色葡萄球菌和大肠杆菌混合液作为诱导源,采用针刺法使黄粉虫Tenebrio molitor L.幼虫感染微生物产生抗菌肽,并对抗菌肽进行了提取、色谱分离纯化及抑菌活性检测。结果显示,诱导组和对照组的三氟乙酸粗提物无抑菌活性;经SephadexG50、SuperdexPeptide凝胶色谱分离后,从诱导组和对照组均可获得对革兰氏阳性菌金黄色葡萄球菌、枯草芽孢杆菌有抑菌作用的组分,而且诱导组活性明显高于对照组;通过Resource 15RPC反相色谱分离纯化,从诱导组获得一具有明显抑制革兰氏阳性菌的组分,质谱检测该组分为混合肽,主要由分子量为1 876.21 u、1 904.21 u的小肽组成,可能是一种比Thanatin分子量更低的昆虫抗菌肽。

Antimicrobial peptides （AMPs） are so effective against bacteria that they are expected to become the new antibiotics. We induced mealworm, Tenebrio molitor L, , larvae to produce AMPs by pricking their abdomens with a stainless needle that had been dipped in a suspension of living Escherichia coli and Staphylococcus aureus. AMPs were then isolated and purified by methods including 0.1% trifluoroacetic acid （ v： v） extraction, gel filtration chromatography on Sephadex G - 50 and Superdex Peptide, and reverse phase high - performance liquid chromatography （ RP - HPLC）. Eventually, a fraction was obtained from the induced group with strong anti - S. aureus and anti - Bacillus subtilis activities. The analysis of matrix - assisted laser desorption ionization time - of - flight mass spectrometry （ MALDI - TOF MS） indicated that the fraction was composed of two small peptides with molecular masses of 1 876.21 u and 1 904.21 u respectively. This suggests that these peptides are insect AMPs of a lower molecular weight than Thanatin.