Iba H, Okada Y
Biochim Biophys Acta. 1981 Mar 26;653(1):61-8. doi: 10.1016/0005-2787(81)90104-0.
Envelope-free nucleoids were isolated from an asymmetrically dividing bacterium, Caulobacter crescentus. In the nucleoid fraction, most of the DNA and nascent RNA in the cell and about 2% of the total cellular proteins were recovered. The sedimentation coefficient of the nucleoid was constant (1260 S) during the G1 period of the swarmer cell cycle and increased to 1940 S during the S period. Since both replicating (S period) and non-replicating (G1 period) chromosomes had a similar superhelical concentration, the increase in the sedimentation coefficient was simply explained by duplication of the nucleoid structure. The duplicated nucleoid was shown to segregate prior to the cell division. The pulse-labeled proteins recovered in the nucleoid fraction contained several stage-specific species, most of which were detected at the beginning of S period.
从不对称分裂的细菌新月柄杆菌中分离出无包膜类核。在类核部分，回收了细胞中大部分的DNA和新生RNA以及约2%的细胞总蛋白。类核的沉降系数在游动细胞周期的G1期保持恒定（1260 S），在S期增加到1940 S。由于复制期（S期）和非复制期（G1期）的染色体具有相似的超螺旋浓度，沉降系数的增加可简单地解释为类核结构的复制。已证明复制后的类核在细胞分裂之前发生分离。在类核部分回收的脉冲标记蛋白包含几种阶段特异性的蛋白质，其中大多数在S期开始时被检测到。
