The alternative oxidase (AOX) catalyzes the transfer of electrons from ubiquinol to oxygen without the translocation of protons across the inner mitochondrial membrane. This enzyme has been proposed to participate in the regulation of cell growth, sporulation, yeast-mycelium transition, resistance to reactive oxygen species, infection, and production of secondary metabolites. Two approaches have been used to evaluate AOX function: incubation of cells for long periods of time with AOX inhibitors or deletion of AOX gene. However, AOX inhibitors might have different targets. To test non-specific effects of n-octyl gallate (nOg) and salicylhydroxamic acid (SHAM) on fungal physiology we measured the growth and respiratory capacity of two fungal strains lacking (Ustilago maydis-Δaox and Saccharomyces cerevisiae) and three species containing the AOX gene (U. maydis WT, Debaryomyces hansenii, and Aspergillus nidulans). For U. maydis, a strong inhibition of growth and respiratory capacity by SHAM was observed, regardless of the presence of AOX. Similarly, A. nidulans mycelial growth was inhibited by low concentrations of nOg independently of AOX expression. In contrast, these inhibitors had no effect or had a minor effect on S. cerevisiae and D. hansenii growth. These results show that nOg and SHAM have AOX independent effects which vary in different microorganisms, indicating that studies based on long-term incubation of cells with these inhibitors should be considered as inconclusive.

替代氧化酶（AOX）催化电子从泛醇转移到氧气，而质子不会穿过线粒体内膜。已经提出该酶参与细胞生长，孢子形成，酵母-菌丝体转变，对活性氧的抗性，感染和次级代谢产物的产生的调节。已使用两种方法评估AOX功能：将细胞与AOX抑制剂长时间孵育或删除AOX基因。但是，AOX抑制剂可能具有不同的靶标。为了测试没食子酸正辛酯（nOg）和水杨基异羟肟酸（SHAM）对真菌生理的非特异性作用，我们测量了两种缺少的真菌菌株（Ustilago maydis- Δaoxand酿酒酵母（Saccharomyces cerevisiae）和三个含有AOX基因的物种（U. maydis WT，汉逊Debaryomyces hansenii和构巢曲霉（Aspergillus nidulans））。对于U. maydis，无论是否存在AOX，均观察到SHAM对生长和呼吸能力的强烈抑制。类似地，低浓度的nOg抑制构巢曲霉菌丝体的生长，而与AOX的表达无关。相比之下，这些抑制剂对酿酒酵母和汉逊酵母无作用或有轻微作用。增长。这些结果表明，nOg和SHAM在不同微生物中具有独立于AOX的作用，这表明基于将细胞与这些抑制剂长期温育的研究不应被认为是结论性的。