Xu Z, Afzelius B A
Department of Ultrastructure Research, Wenner-Gren Institute, University of Stockholm, Sweden.
J Ultrastruct Mol Struct Res. 1988 Jun;99(3):254-60. doi: 10.1016/0889-1605(88)90069-9.
Human blood platelets were exposed to 10 microM adenosine diphosphate in order to induce shape changes and their ultrastructure was examined in preparations fixed with a glutaraldehyde-tannic acid mixture. Within 5 sec after the addition of ADP the marginal bundle along the perimeter of the platelet had undergone profound changes. The intertubular filaments of the marginal bundle were lost and, probably as a consequence, the microtubules were dispersed. The microtubules also had fragmented and appeared as straight rods rather than smoothly curved coils. Profiles with 14 or 15 protofilaments rather than the common 13-unit pattern were seen in 16% of the cross-sectioned microtubules. The proportion of incomplete (C-shaped) microtubules or of microtubules with an electron-dense interior also had increased and were interpreted as sections near the terminal ends of a microtubule. We interpret the C-shaped and the "filled" microtubules as signs of a disassembled microtubule and the 14- and 15-protofilament profiles as probably representing new (ends of) microtubules reassembled with a defective control of the proper structure.
将人血血小板暴露于10微摩尔二磷酸腺苷中以诱导其形态变化，并用戊二醛 - 单宁酸混合物固定标本后检查其超微结构。加入ADP后5秒内，血小板周边的边缘束发生了深刻变化。边缘束的管间细丝消失，可能因此微管分散。微管也已断裂，呈现为直杆而非平滑弯曲的螺旋状。在16%的横切微管中可见具有14或15条原丝的形态，而非常见的13单位模式。不完全（C形）微管或内部有电子致密物的微管比例也增加了，被解释为微管末端附近的切片。我们将C形和“填充”微管解释为微管解聚的迹象，而14和15条原丝的形态可能代表重新组装时结构控制有缺陷的新（微管末端）。
