Matsuoka T, Shigenaka Y, Naitoh Y
Cell Struct Funct. 1985 Mar;10(1):63-70. doi: 10.1247/csf.10.63.
In the large heliozoan Echinosphaerium, contractile tubules (formerly called X-bodies) are located between the axopodial membrane and the axonemal microtubules. When axopodial contraction occurs, the tubules have been thought to be transformed from a tubular to a granular form, as seen in ultra-thin sections. Our detailed morphological observations of the contractile tubules, however, have revealed that this so-called granulation of the contractile tubules is mediated by self-twisting and supercoiling during contraction. We also examined the localization of calcium during axopodial contraction using a potassium pyroantimonate assay. Ca-Sb deposits were detected on contractile tubules only during the twisting and coiling of this organelle. Our results indicate that axopodial contraction is enforced by the twisting and coiling of contractile tubules, which action probably is mediated by Ca2+ ions.
在大型太阳虫类的棘球虫属中，收缩性小管（以前称为X体）位于轴伪足膜和轴丝微管之间。当轴伪足发生收缩时，从小超薄切片中可以看出，这些小管被认为已从管状转变为颗粒状。然而，我们对收缩性小管的详细形态学观察表明，这种所谓的收缩性小管颗粒化是由收缩过程中的自扭曲和超螺旋介导的。我们还使用焦锑酸钾测定法研究了轴伪足收缩过程中钙的定位。仅在该细胞器扭曲和盘绕期间，在收缩性小管上检测到钙-锑沉积物。我们的结果表明，轴伪足收缩是由收缩性小管的扭曲和盘绕加强的，这种作用可能由钙离子介导。
