Chromosome replication in Caulobacter crescentus growing in a nutrient broth
Chromosome replication in Caulobacter crescentus growing in a nutrient broth
复制标题
在营养肉汤中生长的新月柄杆菌的染色体复制
作者：
H. Iba;A. Fukuda;Y. Okada
通过检测新月柄杆菌在快速生长营养肉汤中同步生长过程中脱氧核糖核酸（DNA）合成的速率，研究了新月柄杆菌细胞周期中染色体复制的模式。如先前报道的缓慢生长基本培养基中的细胞周期（Degnen和Newton，1972），营养肉汤中的柄杆菌属细胞周期（以最快的可用生长速率）由DNA合成活性方面的三个不同时期组成。swarmer细胞周期包括合成前期（G1），合成期（S），和合成后期（G2）的30，50和35分钟，分别，而柄细胞周期包括S和G2期的50和35分钟，分别。对营养肉汤中同步生长的细胞进行染色以使核体可视化。在群集细胞和柄细胞中均可见两个核小体，在分裂前细胞中可见四个核小体。化学测定每个细胞的DNA含量，发现在群集细胞和柄细胞中大致相同;它相当于先前报道的动力学复杂性预期值的大约两倍（Wood等人，1976）用于柄杆菌DNA。
The pattern of chromosome replication in the Caulobacter crescentus cell cycle was studied by examining the rate of deoxyribonucleic acid (DNA) synthesis during synchronous growth in a fast-growth nutrient broth. As reported previously for the cell cycle in a slow-growth minimal medium (Degnen and Newton, 1972), the Caulobacter cell cycle (at the fastest available growth rate) in nutrient broth consisted of three distinct periods in terms of DNA synthetic activity. The swarmer-cell cycle consisted of a presynthetic period (G1), synthetic period (S), and postsynthetic period (G2) of 30, 50, and 35 min, respectively, whereas the stalked-cell cycle consisted of S and G2 periods of 50 and 35 min, respectively. Synchronously growing cells in the nutrient broth were stained to visualize nuclear bodies. Two nuclear bodies could be discerned in both swarmer and stalked cells, and four could be discerned in predivisional cells. DNA content per cell was determined chemically and found to be about the same in swarmer and stalked cells; it was equivalent to roughly twice the value expected from the kinetic complexity reported previously (Wood et al., 1976) for Caulobacter DNA.