McDonald K, Pickett-Heaps J D, McIntosh J R, Tippit D H
J Cell Biol. 1977 Aug;74(2):377-88. doi: 10.1083/jcb.74.2.377.
Central spindles from five dividing cells (one metaphase, three anaphase, and one telophase) of Diatoma vulgare were reconstructed from serial sections. Each spindle is made up of two half-spindles that are composed almost entirely of polar microtubules. A small percentage of continuous microtubules and free microtubules were present in every stage except telophase. The half-spindles interdigitate at the midregion of the central spindle, forming a zone of overlap where the microtubules from one pole intermingle with those of the other. At metaphase the overlap zone is fairly extensive, but as elongation proceeds, the spindle poles move apart and the length of the overlap decreases because fewer microtubules are sufficiently long to reach from the pole to the zone of interdigitation. At telophase, only a few tubules are long enough to overlap at the midregion. Concurrent with the decrease in the length of the overlap zone is an increase in the staining density of the intermicrotubule matrix at the same region. These changes in morphology can most easily be explained by assuming zone mechanochemical interaction between microtubules in the overlap zone which results in a sliding apart of the two half-spindles.
从普通硅藻的五个分裂细胞（一个中期、三个后期和一个末期）的中央纺锤体通过连续切片进行了重建。每个纺锤体由两个半纺锤体组成，这两个半纺锤体几乎完全由极微管构成。除末期外，每个阶段都存在少量连续微管和游离微管。半纺锤体在中央纺锤体的中部相互交错，形成一个重叠区，来自一个极的微管与另一个极的微管在此处混合。在中期，重叠区相当广泛，但随着伸长的进行，纺锤体极分开，重叠长度减小，因为足够长到从极延伸到交错区的微管数量减少。在末期，只有少数微管长到足以在中部重叠。与重叠区长度的减小同时发生的是同一区域微管间基质染色密度的增加。这些形态变化最容易通过假设重叠区微管之间的区域机械化学相互作用来解释，这种相互作用导致两个半纺锤体相互滑开。
