Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary.
Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA.
Toxins (Basel). 2018 Apr 20;10(4):168. doi: 10.3390/toxins10040168.
has one gene for alternative oxidase (EC 1.10.3.11). To investigate the relationship between this mitochondrial terminal oxidase and the formation of the mycotoxin sterigmatocystin, the encoding gene was both deleted and overexpressed. Relative to the wild-type, the cyanide-resistant fraction of respiration in the late stationary stage—when sterigmatocystin production occurs—doubled in the overexpressing mutant carrying three gene copies, but decreased to 10% in the deletant. Essentially identical results were obtained regardless whether the cultures were illuminated or protected from light. In contrast, sterigmatocystin yield in the deletant was about half of that in the control when grown in the dark, while overexpression resulted in up to 70% more sterigmatocystin formed, the yield increasing with alternative oxidase activity. Results were quite different when cultures were illuminated: under those conditions, sterigmatocystin volumetric yields were considerably lower, and statistically unvarying, regardless of the presence, absence, or the copy number of . We conclude that the copy number of , and hence, the balance between alternative- and cytochrome C-mediated respiration, appears to correlate with sterigmatocystin production in , albeit only in the absence of light.
它只有一个编码交替氧化酶（EC 1.10.3.11）的基因。为了研究这种线粒体末端氧化酶与真菌毒素桔青霉素形成之间的关系，我们既对其进行了基因缺失，也进行了过表达。与野生型相比，在产桔青霉素的迟滞期（即末期），过表达突变体携带三个 基因拷贝时的氰化物抗性呼吸部分增加了一倍，但在缺失体中减少到 10%。无论培养物是否受到光照或避光保护，都得到了基本相同的结果。相比之下，在黑暗中生长时，缺失体的桔青霉素产量约为对照的一半，而过表达则导致形成的桔青霉素增加了 70%左右，其产量随交替氧化酶活性的增加而增加。当培养物受到光照时，结果则完全不同：在这些条件下，桔青霉素的体积产量明显较低，而且无论 是否存在 ，或 的拷贝数如何，都没有统计学上的变化。我们得出结论， 的拷贝数，以及由此产生的交替呼吸和细胞色素 C 介导呼吸之间的平衡，似乎与 的桔青霉素产量相关，尽管仅在没有光照的情况下如此。
