Response to Hypoxia, Reduction of Electron Acceptors, and Subsequent Survival by Filamentous Fungi
Response to Hypoxia, Reduction of Electron Acceptors, and Subsequent Survival by Filamentous Fungi
复制标题
DOI：
10.1271/bbb.80487
复制
发表时间：
2009-01
期刊：
影响因子：
--
通讯作者：
N. Takaya
中科院分区：
文献类型：
--
作者：
N. Takaya
丝状真菌通常栖息在常氧环境中，利用氧气作为呼吸和生物合成某些必需细胞成分的底物。本文综述了丝状真菌在氧限制（缺氧）条件下的代谢机制。反硝化作用是尖孢镰刀菌和其他真菌将硝酸盐或亚硝酸盐还原为一氧化二氮，产生一氧化氮作为反应中间体的一种机制。细胞色素P450nor作为一氧化氮还原酶的参与是真菌反硝化作用的独特特征，而不是细胞色素bc型一氧化氮还原酶，这是细菌机制所独有的。氨发酵是硝酸盐还原为铵的机制，它允许真菌在缺氧条件下生长。对模式丝状真菌构巢曲霉（Aspergillusnidulans）的研究表明，编码NAD（P）H依赖性硝酸盐还原酶和亚硝酸盐还原酶的niaD和niA对于产生氨是必需的。由于niaD和niiA已被确定为真菌的硝酸盐利用基因，氨发酵和硝酸盐利用机制可能共享硝酸盐还原机制。本文还讨论了近年来有关A. nidulans。
Filamentous fungi usually inhabit normoxic environments by utilizing oxygen as a substrate for respiration and for the biosynthesis of some essential cellular components. This review examines the metabolic mechanisms used by filamentous fungi under oxygen-limited (hypoxic) conditions. Denitrification is one mechanism through which Fusarium oxysporum and other fungi reduce nitrate or nitrite to nitrous oxide, generating nitric oxide as a reaction intermediate. The involvement of cytochrome P450nor as a nitric oxide reductase is a unique feature of fungal denitrification, as opposed to cytochrome bc-type nitric oxide reductase, which is unique to the bacterial mechanism. Ammonia fermentation is the mechanism through which nitrate is reduced to ammonium, and it allows fungal growth under hypoxic conditions. Studies of the model filamentous fungus Aspergillus nidulans have revealed that niaD and niiA encoding NAD(P)H-dependent nitrate and nitrite reductases are essential for producing ammonia. Since niaD and niiA have been identified as genes for nitrate utilization by the fungus, ammonia fermentation and nitrate utilization mechanisms probably share a nitrate-reducing mechanism. I also discuss recent progress in studies of the hypoxic response of A. nidulans.