title: An ultrastructural investigation of 180 degrees-rotated ciliary meridians in Tetrahymena pyriformis.
abstract: An ultrastructural investigation has been carried out on 180 degrees-rotated ciliary meridians (inverted meridians) in Tetrahymena pyriformis temperature-sensitive  mutant (mo1b/mo1b), syngen 1, strain B. The longitudinal, transverse and post-ciliary microtubular bands, the kinetodesmal fiber, and the parasomal sac, are shown to be disposed at a 180 degrees angle to their normal positions or orientations. Other abnormalities are as follows: the first 2 basal bodies of the inverted meridian fail to organize into "couplets" and the inverted meridian intrudes into the anterior pole region; an extra longitudinal microtubular band is found in one of the cell lines.
mesh_terms: D000818:Animals; D002923:Cilia / Q000648:ultrastructure; D008870:Microtubules / Q000648:ultrastructure; D009154:Mutation; D013769:Tetrahymena pyriformis / Q000648:ultrastructure*