Studies On The Cortical Cytoskeleton And Structure Differentiation In Hypotrichous Ciliates

The cortical cytoskeleton is the major component of ciliate cortex, whose shape and structure plays an important role in revealing the cell structure mode of ciliate. To describe its complexity, physiological function, as well as the relationship with other cell structure, three species of ciliate including Euplotes gracilis, Euplotes elegans and Onychodromus quadricornutus were used. By means of scanning electron microscopy and non-ionic detergent extraction, the formation and location of three-dimension network composed of non-ciliated-regional skeleton, cliature skeleton and skeleton-associated fibers was detected; by use of transmission electron microscopy, the ultrastructure of cortical cytoskeleton in interphase and that under the treatment of colchicines was observed; by use of protargol technique, the differentiation of many kinds of ciliature and ciliature-associated fibers was discussed. The result are as follows:1. SEM-observations on the cortical cytoskeleton of Euplotes gracilis after biochemical de-membraneBy means of non-ionic detergent extraction and scanning electron microscopy, it was shown that the cortical cytoskeleton is a three-dimension network composed of non-ciliaed-regional skeleton, ciliature skeleton and skeleton- associated fibers in Euplotes gracilis. All kinds of the skeleton are made up of the fibers forming fiber net, layer, band, sheet and other structural units. The non-ciliaed cortical skeleton is Composed of the surface fiber net and the sub-pellicular fiber layer located in the cortical periphery. The ciliature skeletons, i. e. adoral zone of membranelles skeleton, paroral membrane skeleton and frontal-ventral-transverse cirri skeleton, are located inthe cortex according to their corticotype and form an elementary part of the ventral cytoskeleton. Although These skeletons manifested different appearances, they possessed identical structure, namely a functional unit formed by the kinetosomes, ciliature bracket and skeleton-as-sociated fibers. It was supposed that the fiber net forming the regional structures on the cell surface might play a role in connection of the surface parts and in the interaction between the cell and its environment. It is the first time to show the whole structure of adoral and ventral fiber-network-skeleton in Euplote by means of biochemical de-membrane technique, the result indicate that the shape and arrangement of silverline systen in Euplotes is in accordance with that of in the same species of Euplotes. This network may divide the cell surface into different parts to force the pellicle near the microtubule-organelle inside the cell closer, as well as to make the communication between the cell and environment possible. The ciliature skeleton has several known functions: first, the kinetosomal bracket play a role in the formation of microtubule-organizing-center; second, the skeleton-associated fibers might not only relative to the communication of ciliature inside the cell but harmonize the ciliate movement. For the structure and function of the cell is in close relationship, the kinetosomal complex of ciliature in Euplotes act as microtubule-organizing-center to both ciliature bracket and skeleton-associated fibers and is key to cilia movement. The TEM technique could only show some local structures including sub-pellicle microtubule layer, ciliature and ciliature skeleton, furthermore, the ciliate cell, especially the cortex on the surface of which is so complex, it is most valuable in this paper to use several method to reveal the 3D structure of cortical cytoskeleton in Euplotes for the first time. In ciliature cytoskeleton, the kinetosomal complex might play a role of microtubule-organizing center in the formation of ciliature bracket and skeleton- associated fibers and etc. 2. Ultrastruetural observations on the cortex and cytoskeleton of Euplotes elegant To reveal the shape of ciliate cytoskeleton and its relationship with other kinds ofcellular structure, the structure of Euplotse elegant treated with colchicineand the cell in interphaes were o...