Matsuhashi S, Kamiryo T, Blumberg P M, Linnett P, Willoughby E, Strominger J L
J Bacteriol. 1974 Feb;117(2):578-87. doi: 10.1128/jb.117.2.578-587.1974.
The mechanism of killing of Escherichia coli by a novel beta-lactam antibiotic, an amidino penicillin, has been investigated. This compound converts E. coli to relatively stable spherical forms at low concentration. However, the amidino penicillin caused no alteration in any of those parameters of peptidoglycan synthesis which can be studied. Above 10 mug of the antibiotic per ml the cells began to lyse, and a second mode of killing appeared. Mutants resistant to the amidino penicillin were isolated and several were studied in detail. Three mutant phenotypes were distinguished: (i) spherical shape and hypersensitive to lysis by either amidino penicillin or ampicillin; (ii) spherical shape and normally sensitive to lysis; (iii) rod shape, converted to viable spheres by amidino penicillin and normally sensitive to lysis.
一种新型β-内酰胺抗生素——脒基青霉素对大肠杆菌的杀菌机制已被研究。该化合物在低浓度时可将大肠杆菌转化为相对稳定的球形。然而，脒基青霉素对任何可研究的肽聚糖合成参数均无影响。每毫升抗生素浓度高于10微克时，细胞开始裂解，出现了第二种杀菌模式。分离出了对脒基青霉素耐药的突变体，并对其中几个进行了详细研究。区分出了三种突变体表型：(i) 球形且对脒基青霉素或氨苄青霉素裂解高度敏感；(ii) 球形且对裂解正常敏感；(iii) 杆状，被脒基青霉素转化为活的球形且对裂解正常敏感。
