Leslie R J, Pickett-Heaps J D
J Cell Biol. 1983 Feb;96(2):548-61. doi: 10.1083/jcb.96.2.548.
Our simple instrumentation for generating a UV-microbeam is described UV microbeam irradiations of the central spindle in the pennate diatom Hantzschia amphioxys have been examined through correlated birefringence light microscopy and TEM. A precise correlation between the region of reduced birefringence and the UV-induced lesion in the microtubules (MTs) of the central spindle is demonstrated. The UV beam appears to dissociate MTs, as MT fragments were rarely encountered. The forces associated with metaphase and anaphase spindles have been studied via localized UV-microbeam irradiation of the central spindle. These spindles were found to be subjected to compressional forces, presumably exerted by stretched or contracting chromosomes. Comparisons are made with the results of other writers. These compressional forces caused the poles of a severed anaphase spindle to move toward each other and the center of the cell. As these poles moved centrally, the larger of the two postirradiational central spindle remnants elongated with a concomitant decrease in the length of the overlap. Metaphase spindles, in contrast, did not elongate nor lose their overlap region. Our interpretation is that the force for anaphase spindle elongation in Hantzschia is generated between half-spindles in the region of MT overlap.
我们描述了一种用于产生紫外微束的简单仪器。通过相关双折射光学显微镜和透射电子显微镜（TEM），对羽纹硅藻纤细菱形藻中央纺锤体的紫外微束照射进行了研究。结果表明，中央纺锤体双折射降低的区域与微管（MTs）中紫外线诱导的损伤之间存在精确的相关性。紫外光束似乎会使微管解离，因为很少遇到微管片段。通过对中央纺锤体进行局部紫外微束照射，研究了与中期和后期纺锤体相关的力。发现这些纺锤体受到压缩力，推测是由伸展或收缩的染色体施加的。并与其他作者的结果进行了比较。这些压缩力导致切断的后期纺锤体的两极相互靠近并移向细胞中心。随着这些极向中央移动，两个照射后中央纺锤体残余物中较大的一个会伸长，同时重叠部分的长度会减小。相比之下，中期纺锤体既不伸长也不失去其重叠区域。我们的解释是，纤细菱形藻后期纺锤体伸长的力是在微管重叠区域的半纺锤体之间产生的。
