Division of Crop Protection/Division of Crop Utilisation, Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala, India.
Lett Appl Microbiol. 2012 May;54(5):410-7. doi: 10.1111/j.1472-765X.2012.03223.x. Epub 2012 Mar 6.
The aim of the present study was to purify and characterize a natural antimicrobial compound from Bacillus sp. strain N associated with a novel rhabditid entomopathogenic nematode.
The cell-free culture filtrate of a bacterium associated with a novel entomopathogenic nematode (EPN), Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by column chromatography, and two bioactive compounds were isolated and their chemical structures were established based on spectral analysis. The compounds were identified as 3,4',5-trihydroxystilbene (1) and 3,5-dihydroxy-4-isopropylstilbene (2). The presence of 3,4',5-trihydroxystilbene (resveratrol) is reported for the first time in bacteria. Compound 1 showed antibacterial activity against all the four test bacteria, whereas compound 2 was effective against the Gram-positive bacteria only. Compounds 1 and 2 were active against all the five fungi tested and are more effective than bavistin, the standard fungicide. The antifungal activity of the compounds against the plant pathogenic fungi, Rhizoctonia solani is reported for the first time.
Cell-free extract of the bacterium and isolated stilbenes demonstrated high antibacterial activity against bacteria and fungi especially against plant pathogenic fungi. We conclude that the bacterium-associated EPN are promising sources of natural bioactive secondary metabolites.
Stilbene compounds can be used for the control of fungi and bacteria.
本研究旨在从与一种新型刺线虫相关的芽孢杆菌菌株 N 中纯化和鉴定一种天然抗菌化合物。
与一种新型昆虫病原线虫（小杆线虫属）相关的细菌的无细胞培养滤液表现出很强的抗菌活性。细菌培养滤液的乙酸乙酯提取物通过柱层析进行纯化，分离出两种具有生物活性的化合物，并根据光谱分析确定其化学结构。这些化合物被鉴定为 3,4',5-三羟基芪（1）和 3,5-二羟基-4-异丙基芪（2）。3,4',5-三羟基芪（白藜芦醇）首次在细菌中被发现。化合物 1 对所有 4 种测试细菌均表现出抗菌活性，而化合物 2 仅对革兰氏阳性菌有效。化合物 1 和 2 对所有测试的 5 种真菌均具有活性，并且比标准杀菌剂百菌清更有效。该化合物对植物病原真菌立枯丝核菌的抗真菌活性是首次报道。
细菌的无细胞提取物和分离出的芪类化合物表现出对细菌和真菌，特别是植物病原真菌的高抗菌活性。我们得出结论，与细菌相关的昆虫病原线虫是天然生物活性次生代谢产物的有前途的来源。
芪类化合物可用于控制真菌和细菌。
