Leptographiumbhutanense提取物抑菌活性的初步分析

Preliminary Analysis on Antibacterial Activity of Leptographium bhutanense Extract

内生真菌是动植物体内的微生物类群,其多样性、复杂性和特殊性的特点使其能够产生化学结构新颖、具有多种生物活性的次生代谢产物。本研究采用纸片法检测Leptographium bhutanense发酵提取物对13种致病细菌的抑菌活性,并对抗菌化合物的最低抑菌浓度（MIC）、热稳定性、光稳定性进行检测;同时,采用OSMAC策略寻找产抗菌化合物的最佳培养基、最佳培养时间和最佳接种量。分析显示提取物对3种人体致病细菌（蜡样芽孢杆菌,副溶血性弧菌,溶血性葡萄球菌）具有抑菌活性;其MIC值分别为：12.5mg/mL、6.25 mg/mL和6.25 mg/mL;提取物具有较好的热稳定性和光稳定性。产抗菌化合物的最佳培养基为：MFS,最佳培养时间和最佳接种量分别为15 d和1.0 g/100 mL。本研究为昆虫内生真菌抗菌化合物的开发利用提供帮助。

Endophytic fungi are microorganisms in the body of animals and plants, and their characters of diversity, complexity and specificity make it possible to produce secondary metabolites with novel chemical structure and biological activities. In this study, the antibacterial activity of L. bhutanense fermentation extract on 13 pathogenic bacteria was detected by paper method. We tested the minimum inhibitory concentration（MIC）, thermal stability and photo-stability of antimicrobial compounds. Simultaneously, OSMAC strategy was utilized to find the optimum culture medium, culture time and inoculum size. The analysis indicated that the extract of L. bhutanense had antibacterial activity on three kinds of human pathogenic bacteria（Bacillus cereus,Vibrio parahaemolyticus, Staphylococcus aureus）, the MIC values of which were 12.5 mg/mL, 6.25 mg/mL, and 6.25 mg/mL respectively. The extract also had well thermal stability and light stability. MFS was the optimum culture medium for producing antibacterial compounds. The optimum culture time and inoculum size were 15 d and 1.0 g/100 mL. The study could provide help for the development and utilization in antibacterial compounts of insect endophytic fungi.