Fine structure of basal bodies (kinetosomes) and associated components of Tetrahymena.

Basal bodies (kinetosomes) and adjoining structures, notably the rootlets (kinetodesmal fibres) and a component of the terminal plate, the rosette, have been examined in the electron microscope in sections of whole Tetrahymena and in negatively stained fragments from homogenates. The previously described structure of the basal bodies has been confirmed and certain details, not apparent in sectioned preparations, have been revealed by negative staining. The rosette is a filamentous structure with nine-fold symmetry lying between the fibres of the basal body at the level of the circumciliary ring. The rootlets are composed in the main of a parallel array of filaments with regularly spaced thickenings which, being in register, give rise to a transverse banding with a repeat period of about 320 A. The rootlets are differentiated at one end for attachment to the basal bodies. Some of the structure revealed by negative staining has been analysed by means of optical diffraction.