Higgins M L, Ferrero M, Daneo-Moore L
J Bacteriol. 1986 Aug;167(2):562-9. doi: 10.1128/jb.167.2.562-569.1986.
Exponential-phase cells of Streptococcus faecium were treated with concentrations of ampicillin and cephalothin which, over 60 min, had little effect on increase in culture mass but resulted in about a 65% inhibition of increase in cell numbers. The resulting drug-treated cells underwent about a doubling in cell mass and volume above that of the untreated cells. The newly divided cells produced in the presence of drugs were shown to be due to the division of central or primary sites of envelope growth present at the time of treatment. Sites that were newly initiated (secondary sites) at the time of treatment or sites initiated after treatment did not divide but enlarged in length and girth to give abnormally large cells. Although the increase in average total volume was the same after each interval of treatment with ampicillin and cephalothin, the primary growth sites of the cephalothin-treated cells grew somewhat more slowly, and their secondary sites grew somewhat more quickly, than did those of the ampicillin-treated cells. Cephalothin-treated cells initiated secondary sites at a rate similar to that of the untreated cells, whereas the ampicillin-treated cells exhibited reduced rates of secondary site initiation. Two models are presented that account for these results.
用不同浓度的氨苄青霉素和头孢菌素处理处于指数生长期的粪肠球菌细胞，在60分钟内，这些浓度对培养物质量的增加影响不大，但导致细胞数量增加受到约65%的抑制。与未处理的细胞相比，经药物处理后的细胞质量和体积增加了约一倍。结果表明，在药物存在的情况下产生的新分裂细胞是由于处理时存在的包膜生长的中央或主要位点的分裂。处理时新启动的位点（次要位点）或处理后启动的位点不分裂，而是长度和周长增大，形成异常大的细胞。尽管用氨苄青霉素和头孢菌素进行每次处理间隔后平均总体积的增加是相同的，但头孢菌素处理的细胞的主要生长位点生长速度稍慢，其次要位点的生长速度比氨苄青霉素处理的细胞稍快。头孢菌素处理的细胞启动次要位点的速率与未处理的细胞相似，而氨苄青霉素处理的细胞次要位点启动速率降低。提出了两个解释这些结果的模型。
