Visualization of the microtubules in a mitotic apparatus and study of the mechanism of chromosome movement.

染色体的运动是借助有丝分裂纺锤体中的微管丝进行的，因此对微管动态行为的研究与染色体的运动机制密切相关。我在体外用高强度暗场光显微镜观察单个微管。实时录像显示了以下证据。1)两个微管群体在体外以动态不稳定的方式共存：一个群体中的微管群体拉长，另一个群体中的微管群体缩短。2)微管的两端处于生长或缩短阶段，并在这两个阶段之间以随机方式频繁交替。3)即使在单个微管上，生长端和缩短端也可以共存，一端继续生长，另一端同时缩短。4)无论是单个微管之间还是单个微管两端之间的相变都不存在相关性。5)任一微管的两端具有显著不同的特性；与非活性端相比，活性端生长更快，相位交替更频繁，长度波动更大。6)微管相关蛋白抑制生长阶段的相转换，稳定微管。

Chromosome movement is performed by aid of microtubule filaments in a mitotic spindle, so that the studies on the dynamic hehabiour of microtubules are closely related to the mechanism of the chormosome movement. I visualized individual microtubules in vitro by high intensity dark-field light microscopy. Real-time video recording reveales the following evidences.1) Two populations of microtubules coexist in a dynamically unstable manner in vitro: those in one population elongate while those in the other shorten. 2) Both ends of a microtubule exist in either the growing or the shortening phase and alternate guite frequently between the two phases in a stochastic manner. 3) Growing and shortening ends can coexist even on a single microtubule, one end continuing to grow simultaneously with shortening at the other end. 4) There is no correlation in the phase conversion either among individual microtubules or between the two ends of a single microtubule. 5) The two ends of any given microtubule have remarkably different charactrstics; the active end grows faster, alternates in phase more frequently and fluctuates in length to a greater extent than the inactive end. 6) Microtubule-associated proteins suppress the phase conversion and stabilize microtubules in the growing phase.