Canepari P, Botta G, Satta G
J Bacteriol. 1984 Jan;157(1):130-3. doi: 10.1128/jb.157.1.130-133.1984.
The effect of mecillinam, a beta-lactam antibiotic that specifically binds penicillin-binding protein 2 of Escherichia coli, causes transition from rod to coccal shape, and inhibits cell division in sensitive cells, has been tested on three different E. coli temperature-sensitive cell division mutants. At the nonpermissive temperature, the antibiotic allows an increase in cell number for strains BUG6 and AX655 but not for AX621. In strain AX655, the cell division stimulation was observed only if the antibiotic was added immediately after shifting to the nonpermissive temperature, whereas in BUG6, the rise in cell number was observed also when mecillinam was added after 90 min of incubation at the nonpermissive temperature. In all cases, cell division began occurring 30 min after addition of the antibiotic. Mecillinam had no effect on division of dnaA, dnaB temperature-sensitive mutants or on division of BUG6 derivatives made resistant to this antibiotic. Other beta-lactam antibiotics such as penicillin, ampicillin, cephalexin, and piperacillin and non beta-lactam antibiotics such as fosfomycin, teichomycin, and vancomycin that inhibit cell wall synthesis did not show any effect on cell division for any of the mutants. The response of the three cell division mutants to mecillinam is interpreted in terms of a recently proposed model for shape regulation in bacteria.
美西林是一种β-内酰胺抗生素，它能特异性结合大肠杆菌的青霉素结合蛋白2，使细菌从杆状转变为球菌形状，并抑制敏感细胞的细胞分裂。我们已在三种不同的大肠杆菌温度敏感型细胞分裂突变体上测试了美西林的作用。在非允许温度下，该抗生素能使BUG6和AX655菌株的细胞数量增加，但对AX621菌株无效。在AX655菌株中，只有在转移到非允许温度后立即添加抗生素，才能观察到细胞分裂的刺激作用；而在BUG6菌株中，在非允许温度下孵育90分钟后添加美西林，也能观察到细胞数量的增加。在所有情况下，添加抗生素30分钟后细胞开始分裂。美西林对dnaA、dnaB温度敏感型突变体的分裂或对已对该抗生素产生抗性的BUG6衍生物的分裂均无影响。其他抑制细胞壁合成的β-内酰胺抗生素，如青霉素、氨苄青霉素、头孢氨苄和哌拉西林，以及非β-内酰胺抗生素，如磷霉素、替考拉宁和万古霉素，对任何突变体的细胞分裂均无影响。根据最近提出的细菌形状调控模型，对这三种细胞分裂突变体对美西林的反应进行了解释。
