Hattori Takasumi, Kino Kuniki, Kirimura Kohtaro
Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Curr Microbiol. 2009 Apr;58(4):321-5. doi: 10.1007/s00284-009-9369-z. Epub 2009 Feb 12.
The citric acid-producing fungus Aspergillus niger WU-2223L possesses a cyanide-insensitive respiratory pathway catalyzed by alternative oxidase. The regulation of the alternative oxidase under the conditions of citric acid production was determined from the transcription level of the alternative oxidase gene (aox1). PCR and Southern blot analyses revealed that there is only one copy of aox1 on the chromosome of WU-2223L and no homologous gene of aox1. To confirm the regulation stage of alternative oxidase, alternative oxidase activities and aox1 transcription levels were measured under several cultivation conditions, including those for citric acid production. On each cultivation day, the changes in the specific activity of the alternative oxidase were found to be comparable to those in the transcription level of aox1. These results indicate that the activity of the alternative oxidase encoded by aox1 is regulated at the transcription stage under the conditions tested for A. niger WU-2223L.
产柠檬酸的黑曲霉WU - 2223L拥有一条由交替氧化酶催化的对氰化物不敏感的呼吸途径。在柠檬酸生产条件下，通过交替氧化酶基因（aox1）的转录水平来确定交替氧化酶的调控情况。PCR和Southern杂交分析表明，WU - 2223L染色体上仅存在一个aox1拷贝，且不存在aox1的同源基因。为了确定交替氧化酶的调控阶段，在包括柠檬酸生产条件在内的几种培养条件下测量了交替氧化酶活性和aox1转录水平。在每个培养日，发现交替氧化酶的比活性变化与aox1转录水平的变化相当。这些结果表明，在测试的黑曲霉WU - 2223L条件下，由aox1编码的交替氧化酶的活性在转录阶段受到调控。
