黑翅土白蚁共生真菌BYSTW3的抗菌活性代谢产物

Antimicrobial metabolites of BYSTW3, a symbiotic fungus from Odontotermes formosanus

摘要:

[目的]黑翅土白蚁共生真菌BYSTW3菌株的鉴定及其活性次级代谢产物的研究。[方法]对目标菌株BYSTW3进行形态学观察和ITS序列分析，初步确定其分类地位。采取滤纸片法和生长速率法，分别对该菌株粗提物进行抗细菌、抗真菌活性的测定。综合运用多种色谱柱分离方法对活性成分进行分离纯化，结合多种谱图数据对化合物结构进行解析。[结果]经鉴定，BYSTW3为Pleosporales （格孢腔目）真菌，是一潜在新种。在测试浓度为100μg/mL时，粗提物对苹果树腐烂病菌（Valsa mali）和苦瓜枯萎病菌（Fusarium oxysporum f.sp.mornordicae）表现出中等强度的抑制活性，分别为54.5%和53.4%。通过分离纯化，共得到3个活性化合物Physcion （1）、FK-17-p2a （2）和Citrinin （3），其中化合物1和3均首次从格孢腔目真菌中分离得到。当供试浓度为30μg/滤纸片时，化合物3对金黄色葡萄球菌（Staphylococcus aureus）、枯草芽孢杆菌（Bacillus subtilis）、大肠杆菌（Escherichia coli）均具有良好的抑菌作用，抑菌圈直径分别为23.0、24.2、20.7 mm。[结论]BYSTW3是一株发展前景较为良好的潜在新菌，具有开发微生物源杀菌剂的潜在研究价值。

Abstract:

[Objective] We identified fungus BYSTW3, from Odontotermes formosanus, and studied its active secondary metabolites. [Methods] BYSTW3 was identified by morphological observation and ITS (Internal Transcribed Spacer) sequence analysis. The antibacterial and antifungal activities of crude extracts were tested by filter paper method and growth rate method respectively. The crude extracts were separated and purified by a variety of chromatographic column separation methods, and the structures of the compounds were analyzed with a variety of spectral data. [Results] Strain BYSTW3 was identified as a potential new species of Pleosporales sp. The crude extract of BYSTW3 inhibited radical growth of Valsa mali and Fusarium oxysporum f. sp. mornordicae with the inhibition rates of 54.5% and 53.4% at the concentration of 100 μg/mL. Bioactivity-guided fractionation lead to the isolation of three fungal metabolites 1−3, including physcion (1), FK-17-p2a (2) and citrinin (3). Both compounds 1 and 3 were firstly isolated from the fungus of Pleosporales sp.. At the concentration of 30 μg/disc, compound 3 showed potent antibacterial activity against Staphyloccocus aureus, Bacillus subtilis and Escherichia coli with the mean halo diameter of 23.0 mm, 24.2 mm and 20.7 mm, respectively. [Conclusion] BYSTW3 is a potential new strain with good prospects as a new antimicrobial agents from microbial resources.