辣椒籽抗菌肽对黄曲霉的抑制作用

Inhibitory effects of pepper seed antifungal peptide against Aspergillus flavus

研究辣椒籽抗菌肽对玉米中分离的致腐菌(黄曲霉)的作用方式,包括最低抑菌浓度(minimum inhibitory concentration,MIC)、以及对黄曲霉生长、孢子萌发、养分吸收及细胞膜透性的影响。辣椒籽抗菌肽能够抑制黄曲霉生长,在1MIC浓度下萌发率降至18. 51%,浓度达到4MIC时能完全抑制黄曲霉孢子的萌发。在黄曲霉菌快速生长但还未产生孢子的时期(24 h)加入抗菌肽,能有效抑制孢子的产生。在黄曲霉生长的不同阶段(0、24、48 h)加入辣椒籽抗菌肽,其利用培养基中营养物质能力显著降低;通过核酸染料Sytox Green(SG)结合荧光显微镜来研究辣椒籽抗菌肽对黄曲霉的细胞通透性,结果显示,抗菌肽处理后黄曲霉菌丝体细胞内出现荧光,说明细胞膜受到损伤导致通透性发生了改变。

In order to clarify the inhibition mechanisms of pepper seed antifungal peptide( AMP) against cornmildewing Aspergillus flavus,its minimum inhibitory concentration( MIC) and its effects on growth,spore germination,nutrient uptake,and cell membrane permeability of A. flavus were studied. The results showed that pepper seed AMP could inhibit the growth of A. flavus with the MIC of 156. 25 μg/m L. At one-fold MIC,the germination rates of spores decreased to 18. 51% and were completely inhibited at four-fold MIC. When AMP was added during the vegetative growth( in 24 h) of A. flavus,it could effectively inhibit spore formation. When AMP was added at different growth stages(0,24,48 h),it significantly reduced the ability of A. flavus to absorb nutrients from the medium. Sytox Green( SG) combined with a fluorescent microscope showed that the mycelium of AMP-treated A. flavus showed fluorescence,indicated that the cell membrane of A. flavus was damaged and therefore its permeability changed.