越南槐内生真菌GRPH-0的抗真菌活性及其鉴定

Antifungal activity and taxonomic identification of endophytic fungus GRPH-0 isolated from Sophora tonkinensis Gapnep

目的为新型抗生素的研究提供有价值的菌种资源。方法采用改良的琼脂扩散法从越南槐内生真菌中筛选拮抗白念珠菌的活性菌株并测定其对念珠菌属真菌的抑菌谱;以改良的微量肉汤稀释法测定其代谢产物的抗菌活性;根据形态和分子特征鉴定该菌株的分类学地位。结果菌株GRPH-0活菌块对白念珠菌的抑菌圈直径比阳性对照大,并且对参试念珠菌属真菌均具有不同程度的抑制作用,具有较广的抑菌谱;其代谢产物对白念珠菌及其多重耐药临床分离株的最小抑菌浓度均为4μg/m L,仅为阳性对照的16倍;初步鉴定该菌株为疣孢漆斑菌。结论菌株GRPH-0鉴定为疣孢漆斑菌,对参试病原真菌均显示强的抗真菌活性,具有较大的开发应用潜力。

Objective To provide a valuable resource for the research of novel antibiotics. Methods The antifungal strains against Candida albicans were screened from endophytic fungi isolated from Sophora tonkinensis Gapnep, and the antimicrobial spectrum of these strains against Candida species was sequentially tested using the modified agar disc diffusion method. The in vitro antifungal activity of the metabolites from these strains was tested using the modified broth microdilution method. The taxonomic identification of these strains was based on morphological characters and molecular characters. Results The diameter of the inhibition zone from the mycelial plug of endophytic fungus GRPH-0 against C. albicans was greater than that of the positive control. This strain had different inhibitory actions on Candida species and demonstrateda broad antimicrobial spectrum. The minimal inhibitory concentration values of the metabolites from this strain against Candida albicans and multidrug- resistant isolates in clinical were both 4~tg/mL and sixteen times higher than that of positive control. This strain was preliminarily named as Myrothecium verrucaria. Conclusion The strain GRPH-0 was preliminarily identified as M. verrucaria, and exhibited strong antifungal activity against pathogenic fungi tested. It will have a bright prospect for further exploration and utilization.