DMCA
ULTRASTRUCTURE OF THE PROXIMAL REGION OF SOMATIC CILIA IN PARAMECIUM TETRA URELIA
| Citations: | 5 - 0 self |
BibTeX
@MISC{Dute_ultrastructureof,
author = {Roland Dute and Ching Kung},
title = {ULTRASTRUCTURE OF THE PROXIMAL REGION OF SOMATIC CILIA IN PARAMECIUM TETRA URELIA},
year = {}
}
Share
 |
 |
 |
 |
||
OpenURL
Abstract
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. KEY WORDS cilia 9 Paramecium plaques 9 polycationic ferritin transition zone membrane Recent studies show that there are specialized structures at the proximal region of the cilium just above the basal body. Electron microscope examination of freeze-fractured material shows rings of 7-8-nm particles, the necklace, in the ciliary membrane at its junction with the plasma membrane in Mytilus gill (26). In certain protozoan cilia, many
Keyphrases
terminal plate axosomal plate basal body transition zone various internal structural linkage freeze-fracture material transition-zone specialization outer doublet microtubule polycationic ferritin future study outer membrane surface electron microscope examination ciliary necklace ciliary beating mode plasma membrane mytilus gill transition region thin-section technique three-dimensional model membrane specialization proximal set proximal region form plaquelike array axoneme reach connect adjacent outer doublet plaque region ciliary membrane proximal boundary specialized structure certain protozoan cilium plaque particle wild-type paramecium somatic cilium reverse beating nine transitional fiber paramecium tetraurelia intermediate plate paramecium plaque central tubule key word 7-8-nm particle possible function freeze-fractured material show ring unit membrane
