Terawaki Y, Rownd R
J Bacteriol. 1972 Feb;109(2):492-8. doi: 10.1128/jb.109.2.492-498.1972.
The replication of the R factor Rts1 in Proteus mirabilis was examined by using the technique of CsCl density-gradient centrifugation. The proportion of Rts1 deoxyribonucleic acid (DNA) relative to the host chromosomal DNA (% R-DNA) was 7% in both exponential and stationary growth phases in Penassay Broth and supplemented M9 minimal medium at 30 C. The chromosomal DNA content per cell varied over a threefold range in the different growth media. In agreement with previous genetic observations, the replication of Rts1 was found to be temperature-sensitive and Rts1 DNA was diluted from the cells during exponential growth at 42 C. (14)N-(15)N medium transfer experiments have shown that individual copies of Rts1 are selected at random for replication during the duplication of the multicopy episome pool.
运用氯化铯密度梯度离心技术，对奇异变形杆菌中R因子Rts1的复制情况进行了检测。在30℃的检测肉汤培养基和添加了营养成分的M9基本培养基中，处于指数生长期和稳定期的细菌内，Rts1脱氧核糖核酸（DNA）相对于宿主染色体DNA的比例（% R-DNA）均为7%。在不同的生长培养基中，每个细胞的染色体DNA含量在三倍的范围内变化。与之前的遗传学观察结果一致，发现Rts1的复制具有温度敏感性，并且在42℃的指数生长期，Rts1 DNA会从细胞中被稀释掉。（14）N-（15）N培养基转移实验表明，在多拷贝附加体库复制过程中，Rts1的各个拷贝是随机被选择用于复制的。
