Tang M S, Helmstetter C E
J Bacteriol. 1980 Mar;141(3):1148-56. doi: 10.1128/jb.141.3.1148-1156.1980.
Cell division properties of Escherichia coli B/r containing either a dnaC or a dnaI mutation were examined. Incubation at nonpermissive temperature resulted in the eventual production of cells of approximately normal size, or slightly smaller, which lacked chromosomal DNA. The cell division patterns in cultures which were grown at permissive temperature and then shifted to nonpermissive temperature were consistent with: first, division and equipartition of chromosomes by cells which were in the C and D periods at the time of the shift; second, an apparent delay in cell division; and third, commencement of the formation of chromosomeless cells. In glucose-grown cultures of the dnaI mutant, production of chromosomeless cells continued for at least 120 min, whereas in the dnaC mutant chromosomeless cells were formed during a single interval between 110 and 130 min after the temperature shift. The results are discussed in light of the hypothesis that replication of a specific chromosomal region is not an obligatory requirement for the initiation and completion of the processes leading to division in a cell which contains at least one functioning chromosome.
对含有dnaC或dnaI突变的大肠杆菌B/r的细胞分裂特性进行了研究。在非允许温度下培养最终会产生大小约正常或略小的细胞，这些细胞缺乏染色体DNA。在允许温度下生长然后转移到非允许温度的培养物中的细胞分裂模式符合以下情况：第一，在转移时处于C期和D期的细胞对染色体进行分裂和均等分配；第二，细胞分裂明显延迟；第三，开始形成无染色体细胞。在以葡萄糖为培养基生长的dnaI突变体培养物中，无染色体细胞的产生持续至少120分钟，而在dnaC突变体中，无染色体细胞在温度转移后110至130分钟的单个时间段内形成。根据以下假设对结果进行了讨论：对于导致含有至少一条功能染色体的细胞进行分裂的过程的启动和完成而言，特定染色体区域的复制并非必要条件。
