Iterson W V, Aten J A
J Bacteriol. 1976 Apr;126(1):384-99. doi: 10.1128/jb.126.1.384-399.1976.
The changes in the morphology of the nucleoids and the mesosomes in Bacillus subtilis cells during synchronous outgrowth after spore germination were followed in large-scale three-dimensional cell reconstructions. Shortly after outgrowth of the cell begins in Spizizen medium with glucose, the mesosome becomes an elongated structure in close contact with a rounded nucleoid. When nuclear replication reaches full activity, the mesosome develops into a single, complicated versatile system, with tubules that traverse the cytoplasm and have elaborations in and near the nucleoplasm. Later the system may retract to form large rounded mesosomes; the tubules and strings of vesicles within these mesosomes probably have been collected from the cytoplasm. Shortly after the first cell division, both sister cells have two nucleoids, but with longer generation times induced by growth in media containing acetate instead of glucose; these sister cells have only one nucleoid each. In acetate-grown cells rounded nucleoids that have no contact with a mesosome may represent nucleoids in a temporary stage of rest. On the other hand, the nucleoids of cells growing in glucose-containing medium are always penetrated by mesosomal material, superficially or deeply. Since the mesosome appears capable of traversing the nuclear fibrils, and even reaching the last strands connecting the dividing nucleoids, it is suggested that this organelle may play a vital role in the Bacillus division cycle.
通过大规模三维细胞重建，追踪了枯草芽孢杆菌孢子萌发后同步生长过程中类核和中体形态的变化。在含有葡萄糖的斯皮兹森培养基中细胞开始生长后不久，中体变成与圆形类核紧密接触的细长结构。当核复制达到完全活跃时，中体发展成一个单一的、复杂的多功能系统，其小管穿过细胞质并在核质内和附近有分支。后来这个系统可能会收缩形成大的圆形中体；这些中体内的小管和囊泡串可能是从细胞质中收集而来的。第一次细胞分裂后不久，两个子细胞都有两个类核，但在含有醋酸盐而非葡萄糖的培养基中生长时，由于代时延长，这些子细胞各自只有一个类核。在醋酸盐培养的细胞中，与中体无接触的圆形类核可能代表处于暂时静止阶段的类核。另一方面，在含葡萄糖培养基中生长的细胞的类核总是被中体物质浅层或深层穿透。由于中体似乎能够穿过核纤维，甚至到达连接正在分裂的类核的最后几条链，因此有人认为这个细胞器可能在芽孢杆菌的分裂周期中起至关重要的作用。
