Nordström K, Austin S J
Department of Microbiology, Uppsala University, Sweden.
Mol Microbiol. 1993 Nov;10(3):457-63. doi: 10.1111/j.1365-2958.1993.tb00918.x.
The following characteristics are relevant when replication of chromosomes and plasmids is discussed in relation to the cell cycle: the timing or replication, the selection of molecules for replication, and the coordination of multiple initiation events within a single cell cycle. Several fundamentally different methods have been used to study these processes: Meselson-Stahl density-shift experiments, experiments with the so-called 'baby machine', sorting of cells according to size, and flow cytometry. The evidence for precise timing and co-ordination of chromosome replication in Escherichia coli is overwhelming. Similarly, the high-copy-number plasmid ColE1 and the low-copy-number plasmids R1/R100 without any doubt replicate randomly throughout the cell cycle. Data about the low-copy-number plasmids F and P1 are conflicting. This calls for new types of experiments and for a better understanding of how these plasmids control their replication and partitioning.
当讨论染色体和质粒的复制与细胞周期的关系时，以下特征是相关的：复制时间、用于复制的分子选择以及单个细胞周期内多个起始事件的协调。已经使用了几种根本不同的方法来研究这些过程：梅塞尔森-斯塔尔密度转移实验、使用所谓“婴儿机器”的实验、根据大小对细胞进行分选以及流式细胞术。大肠杆菌中染色体复制精确时间和协调的证据是压倒性的。同样，高拷贝数质粒ColE1和低拷贝数质粒R1/R100无疑在整个细胞周期中随机复制。关于低拷贝数质粒F和P1的数据相互矛盾。这就需要新型实验，并更好地理解这些质粒如何控制它们的复制和分配。
