Yudkin M D
J Bacteriol. 1977 Apr;130(1):57-61. doi: 10.1128/jb.130.1.57-61.1977.
From strains of Escherichia coli that carry deletions of the trp region, five different mutants were isolated that were capable of synthesizing tryptophanase at unusually high rates in conditions of severe catabolite repression. Notwithstanding the comparative insensitivity to catabolite repression, the rates of tryptophanase synthesis in the mutants were greatly diminished by the introduction of a defective gene for adenyl cyclase. Each of the mutants segregated variants of the parental type. The results of genetic analysis appear to be consistent with the mutants arose by duplication of the tryptophanase gene.
从携带色氨酸区域缺失的大肠杆菌菌株中,分离出了五个不同的突变体,它们能够在严重的分解代谢物阻遏条件下以异常高的速率合成色氨酸酶。尽管对分解代谢物阻遏相对不敏感,但通过引入有缺陷的腺苷酸环化酶基因,突变体中色氨酸酶的合成速率大大降低。每个突变体都分离出了亲本类型的变体。遗传分析结果似乎与这些突变体是由色氨酸酶基因复制产生的这一观点一致。