Pateman J A, Kinghorn J R, Dunn E
J Bacteriol. 1974 Aug;119(2):534-42. doi: 10.1128/jb.119.2.534-542.1974.
Wild-type cells of Aspergillus nidulans synthesize a transport system which appears to be specific for l-glutamate and l-aspartate. The system is energy dependent and concentrates l-glutamate at least 60-fold. In cells grown in the presence of 1% sucrose, l-glutamate uptake activity is regulated by ammonium control, although it is not certain whether this is at the level of transcription or translation. Mutants that are insensitive to ammonium control of certain other unrelated systems, e.g., nitrate reductase, are also insensitive, except in the case of one class of ammonium-insensitive mutants, to ammonium control of l-glutamate transport. The activity of this transport system is specifically impaired in a mutant at the aauA locus. This mutation results in poor growth with l-glutamate or l-aspartate as the sole carbon or nitrogen source and is recessive in the heterozygous diploid aauA1/+ for transport and growth characteristics. The likelihood that the mutation results in a defect of the transport mechanism rather than abnormal ammonium control is discussed.
构巢曲霉的野生型细胞合成一种转运系统，该系统似乎对L-谷氨酸和L-天冬氨酸具有特异性。该系统依赖能量，能将L-谷氨酸浓缩至少60倍。在1%蔗糖存在下生长的细胞中，L-谷氨酸摄取活性受铵调控，不过尚不确定这是在转录水平还是翻译水平。对某些其他不相关系统（如硝酸还原酶）的铵调控不敏感的突变体，除了一类对铵不敏感的突变体，对L-谷氨酸转运的铵调控也不敏感。该转运系统的活性在aauA位点的一个突变体中受到特异性损害。这种突变导致以L-谷氨酸或L-天冬氨酸作为唯一碳源或氮源时生长不良，并且在杂合二倍体aauA1/+中，其转运和生长特性是隐性的。文中讨论了该突变导致转运机制缺陷而非异常铵调控的可能性。
