College of Innovation and Management, Songkhla Rajabhat University, Songkhla 90000, Thailand.
Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama 9390398, Japan.
J Appl Microbiol. 2023 Feb 16;134(2). doi: 10.1093/jambio/lxac091.
The study reports the antifungal and antiaflatoxigenic mechanism activity of freeze-dried culture filtrate of Streptomyces philanthi RL-1-178 (DCF RL-1-178) against two aflatoxigenic strains (Aspergillus parasiticus and A. flavus) and identification of its active component.
Significant inhibition in ergosterol biosynthesis by the DCF RL-1-178 appeared on the plasma membrane. Moreover, the DCF RL-1-178 showed dose-dependent inhibition of methylglyoxal (MG) (an aflatoxin inducer) biosynthesis and exhibited a novel antiaflatoxigenic action mechanism. Significant impairments in enzymatic [superoxide dismutase (SOD) and catalase (CAT)] and nonenzymatic [oxidized and reduced glutathione (GSH) and ratio of oxidized and reduced glutathione (GSSG)] anti-oxidative defense molecules were observed in the two aflatoxigenic cells. The active component of the DCF RL-1-178 was identified as natamycin. The natamycin exhibited against A. parasiticus and A. flavus with the minimum inhibitory concentration (MIC) values of 0.5 and 1.0 µg ml-1, respectively, while the minimum fungicidal concentration values were the same (4.0 µg ml-1).
The DCF RL-1-178 containing natamycin exhibited the following effects: (1) inhibition of cellular ergosterol biosynthesis on plasma membrane, (2) reduction in MG (aflatoxin inducer) confirmed novel antiaflatoxigenic mechanism of action, and (3) caused remarkable debasement in antioxidant defense enzymes (SOD and CAT) and nonenzymatic defense molecules (GSH and GSSG) revealing biochemical mechanism of action.
本研究报告了吸水链霉菌 RL-1-178（DCF RL-1-178）冻干培养滤液的抗真菌和抗黄曲霉毒素作用机制，该作用机制针对两种产黄曲霉毒素菌株（寄生曲霉和黄曲霉），并鉴定了其有效成分。
DCF RL-1-178 对细胞膜上麦角甾醇生物合成有显著抑制作用。此外，DCF RL-1-178 对甲基乙二醛（MG）（黄曲霉毒素诱导剂）的生物合成表现出剂量依赖性抑制作用，并表现出一种新的抗黄曲霉毒素作用机制。在两种产黄曲霉毒素细胞中，观察到酶（超氧化物歧化酶（SOD）和过氧化氢酶（CAT））和非酶（氧化和还原谷胱甘肽（GSH）和氧化和还原谷胱甘肽（GSSG）比值）抗氧化防御分子显著受损。DCF RL-1-178 的有效成分被鉴定为纳他霉素。纳他霉素对寄生曲霉和黄曲霉的最小抑菌浓度（MIC）值分别为 0.5 和 1.0 μg ml-1，而最小杀菌浓度值相同（4.0 μg ml-1）。
含纳他霉素的 DCF RL-1-178 具有以下作用：（1）抑制细胞膜上细胞麦角甾醇生物合成，（2）减少 MG（黄曲霉毒素诱导剂）证实了新的抗黄曲霉毒素作用机制，（3）导致抗氧化防御酶（SOD 和 CAT）和非酶防御分子（GSH 和 GSSG）显著下降，揭示了其生化作用机制。
