Li Sheng-Fa, Zhang Shuai-Bing, Lv Yang-Yong, Zhai Huan-Chen, Li Na, Hu Yuan-Sen, Cai Jing-Ping
College of Biological Engineering, Henan University of Technology, 100 Lianhua Street, Zhengzhou, 450001, Henan, China.
Appl Microbiol Biotechnol. 2021 May;105(9):3745-3757. doi: 10.1007/s00253-021-11293-z. Epub 2021 Apr 20.
Hexanal, a natural volatile organic compound, exerts antifungal activity against Aspergillus flavus; however, the mechanisms underlying these effects are unclear. In this study, we found that the growth of A. flavus mycelium was completely inhibited following exposure to 0.4 μL/mL hexanal (minimal inhibitory concentration). A detailed metabolomics survey was performed to identify changes in metabolite production by A. flavus cells after exposure to 1/2 the minimal inhibitory concentration of hexanal for 6 h, which revealed significant differences in 70 metabolites, including 20 upregulated and 50 downregulated metabolites. Among them, levels of L-malic acid, α-linolenic acid, phosphatidylcholine, D-ribose, riboflavin, D-mannitol, D-sorbitol, and deoxyinosine were significantly reduced. The metabolomics results suggest that the metabolites are mainly involved in the tricarboxylic acid cycle (TCA), ABC transport system, and membrane synthesis in A. flavus cells. Hexanal treatment reduced succinate dehydrogenase and mitochondrial dehydrogenase activity and stimulated superoxide anion and hydrogen peroxide accumulation in A. flavus mycelia. Increases in the electric conductivity and A of the culture supernatant indicated cell membrane leakage. Therefore, hexanal appears to disrupt cell membrane synthesis, induce mitochondrial dysfunction, and increase oxidative stress in A. flavus mycelia. KEY POINTS: • Metabolite changes of A. flavus mycelia were identified after hexanal treatment. • Most differential metabolites were downregulated in hexanal-treated A. flavus. • An antifungal model of hexanal against A. flavus was proposed.
己醛是一种天然挥发性有机化合物，对黄曲霉具有抗真菌活性；然而，这些作用的潜在机制尚不清楚。在本研究中，我们发现，暴露于0.4 μL/mL己醛（最小抑菌浓度）后，黄曲霉菌丝体的生长被完全抑制。进行了详细的代谢组学调查，以确定黄曲霉细胞在暴露于1/2最小抑菌浓度的己醛6小时后代谢产物产生的变化，结果显示70种代谢产物存在显著差异，包括20种上调代谢产物和50种下调代谢产物。其中，L-苹果酸、α-亚麻酸、磷脂酰胆碱、D-核糖、核黄素、D-甘露醇、D-山梨醇和脱氧肌苷的水平显著降低。代谢组学结果表明，这些代谢产物主要参与黄曲霉细胞的三羧酸循环（TCA）、ABC转运系统和膜合成。己醛处理降低了黄曲霉菌丝体中琥珀酸脱氢酶和线粒体脱氢酶的活性，并刺激了超氧阴离子和过氧化氢的积累。培养上清液的电导率和A值增加表明细胞膜渗漏。因此，己醛似乎会破坏黄曲霉菌丝体的细胞膜合成，诱导线粒体功能障碍，并增加氧化应激。要点：• 确定了己醛处理后黄曲霉菌丝体的代谢物变化。• 在己醛处理的黄曲霉中，大多数差异代谢物下调。• 提出了己醛对黄曲霉的抗真菌模型。
