Chakrabarti S L, Maitra P K
J Bacteriol. 1974 Jun;118(3):1179-80. doi: 10.1128/jb.118.3.1179-1180.1974.
Several streptomycin-resistant mutants of Escherichia coli have been isolated which require exogenous isoleucine for growth. The majority of these strains were of streptomycin-dependent phenotype. If grown in the absence of streptomycin, these streptomycin-dependent auxotrophs (Sm(d-aux)) strains were unable to produce beta-galactosidase and aldolase activities and also failed to exhibit donor properties in conjugation. Genetic analysis indicated that the isoleucine requirement of these strains could be caused by a mutation at the strA locus.
已分离出几种大肠杆菌的链霉素抗性突变体，它们生长需要外源性异亮氨酸。这些菌株中的大多数具有链霉素依赖型表型。如果在没有链霉素的情况下生长，这些链霉素依赖型营养缺陷型（Sm(d-aux)）菌株无法产生β-半乳糖苷酶和醛缩酶活性，并且在接合中也未能表现出供体特性。遗传分析表明，这些菌株对异亮氨酸的需求可能是由strA位点的突变引起的。
