Goldberg R B, Chargaff E
Proc Natl Acad Sci U S A. 1971 Aug;68(8):1702-6. doi: 10.1073/pnas.68.8.1702.
The mode of induction of beta-galactosidase (EC 3.2.1.23) in synchronously growing cultures of two Hfr strains of Escherichia coli K12 was investigated. Cells can be induced to form the enzyme during any portion of the cell cycle; but when they are grown permanently in the presence of an inducer, enzyme synthesis is discontinuous. The interruption of beta-galactosidase synthesis appears to be geared to the growth cycle: it occurs when the cells are dividing actively. The observation that lac-specific messenger RNA is produced also in the absence of detectable enzyme synthesis suggests the existence of a control mechanism operating on the level of translation.
对大肠杆菌K12的两个高频重组（Hfr）菌株同步生长培养物中β-半乳糖苷酶（EC 3.2.1.23）的诱导模式进行了研究。在细胞周期的任何阶段，细胞都可被诱导形成该酶；但当细胞在诱导剂存在的情况下持续生长时，酶的合成是不连续的。β-半乳糖苷酶合成的中断似乎与生长周期相关：它发生在细胞活跃分裂时。即使在没有可检测到的酶合成的情况下也会产生乳糖特异性信使核糖核酸这一观察结果表明，存在一种在翻译水平上起作用的控制机制。
