Morishita T, Yura T
J Bacteriol. 1976 Feb;125(2):416-22. doi: 10.1128/jb.125.2.416-422.1976.
Rifampin-resistant mutants were isolated from Lactobacillus casei S1 and examined for possible simultaneous alteration in nutritional properties. Among the 36 mutants obtained either spontaneously or after mutagenesis with 2-aminopurine, 22 were found to be altered with respect to the specific growth requirements. The majority (20 of 22) of the latter mutants were shown to require L-glutamine in addition to the nutrients required by the parental strain for maximal growth, whereas the remaining mutants had apparently lost the requirement for L-aspartate. Further studies with one of the glutamine-requiring mutants revealed that the rifampin resistance of this strain is due to the resistance of ribonucleic acid polymerase itself and that a single mutation is responsible for both rifampin resistance and the glutamine requirement. These results strongly indicate that a structural alteration of the ribonucleic acid polymerase caused by the rifampin resistance mutation somehow affected glutamine metabolism, possibly through change in selective transcription of the genes involved.
从干酪乳杆菌S1中分离出耐利福平突变体，并检测其营养特性是否可能同时发生改变。在通过自发突变或用2-氨基嘌呤诱变获得的36个突变体中，发现有22个在特定生长需求方面发生了改变。后一类突变体中的大多数（22个中的20个）显示，除了亲代菌株生长所需的营养物质外，还需要L-谷氨酰胺才能实现最大生长，而其余突变体显然不再需要L-天冬氨酸。对其中一个需要谷氨酰胺的突变体进行的进一步研究表明，该菌株对利福平的抗性是由于核糖核酸聚合酶本身具有抗性，并且单个突变导致了对利福平的抗性和对谷氨酰胺的需求。这些结果有力地表明，由利福平抗性突变引起的核糖核酸聚合酶结构改变以某种方式影响了谷氨酰胺代谢，可能是通过改变相关基因的选择性转录来实现的。
