Ultrastructure of the proximal region of somatic cilia in Paramecium tetraurelia.
Ultrastructure of the proximal region of somatic cilia in Paramecium tetraurelia.
复制标题
DOI：
10.1083/jcb.78.2.451
复制
发表时间：
1978-08
期刊：
影响因子：
--
通讯作者：
Kung C
中科院分区：
文献类型：
--
作者：
Dute R;Kung C
本文研究了四毛草履虫（Paramecium tetraurelia）基部终板与体细胞（非口腔）纤毛9 + 2区之间的过渡区形态。冻裂和薄片技术揭示了膜的特化和各种内部结构的联系。冻裂材料显示出一组颗粒打断了单元膜。较远端的颗粒形成斑块状排列，而较近的颗粒形成纤毛“项链”。斑块区域与外膜表面的阴离子位点相对应，这是由多阳离子铁蛋白结合所揭示的。斑块颗粒和项链颗粒似乎都是通过连接结构的复合体与外部双态微管接触。在过渡区的内部，轴小体板支撑轴小体，轴小体被一圈轻填充的物质包围。轴突体的两个中心小管中只有一个到达并穿透轴突体。轴小体板下四个环，每个环约。20nm宽，连接相邻的外部双极。一个中间板块位于这些环的近端，一个终端板块标志着这个带的近端边界。九根过渡纤维从终板区域延伸到质膜。利用上述观察结果构建了“野生型”草履虫体细胞纤毛过渡区的三维模型。由于草履虫可以在正常和反向纤毛跳动模式下进行检测，并且由于无法反向跳动的突变体是可用的，因此预计该模型将在未来关于过渡区特化可能功能的研究中有用。
The morphology of the transition zone between the terminal plate of the basal body and the 9 + 2 region of the somatic (non-oral) cilium has been examined in Paramecium tetraurelia. Freeze-fracture and thin- section techniques disclosed both membrane specializations and various internal structural linkages. Freeze-fracture material revealed sets of particles interrupting the unit membrane. The more distal of these form plaquelike arrays while the proximal set of particles forms the ciliary "necklace." The plaque regions correspond to anionic sites on the outer membrane surface as revealed by binding of polycationic ferritin. Both the plaque particles and the necklace particles appear to be in contact with outer doublet microtubules via a complex of connecting structures. In the interior of the transition zone an axosomal plate supports an axosome surrounded by a ring of lightly packed material. Only one of the two central tubules of the axoneme reaches and penetrates the axosome. Below the axosomal plate four rings, each approx. 20 nm wide, connect adjacent outer doublets. An intermediate plate lies proximal to these rings, and a terminal plate marks the proximal boundary of this zone. Nine transitional fibers extend from the region of the terminal plate to the plasmalemma. The observations described above have been used to construct a three-dimensional model of the transition region of "wild-type" Paramecium somatic cilia. It is anticipated that this model will be useful in future studies concerning possible function of transition-zone specializations, since Paramecium may be examined in both normal and reversed ciliary beating modes, and since mutants incapable of reverse beating are available.