[An ultrastructural study on resting cyst of Euplotes encysticus]

For resting cysts of Euplotes encysticus, in their various ciliatures, most of the ciliary shafts above the cilia kinetosomes are degenerated, or preserve their kinetosomes only. Sometimes, kinetosomes of certain frontal and ventral cirri are also disintegrated and disappeared. For remaining cilia, on their shafts, peripheral doublet microtubule (MT) and central pair of MTs still possess their structural pattern of "9 + 2". In few ciliary shafts, the phenomena of 2 sets of "9 + 2" structures surrounded by a common sheath can also be seen. At the center of kinetosomal peripheral triplets (triplet MTs), aggregates of MT-like structures are formed. For kinetosomal accessory structures, only residues of inter-kinetosomal connections and ciliature brackets can be seen. No MT layers can be seen under the pellicles of non-ciliated cortex. At the ciliated cortex, there are peripheral MT layers (corresponding to sub-pellicular MT layers) within the ciliature cavity, MT ribbons at (and near) the deeper parts of ciliature, and scattered MT groups. Besides, various shapes of ciliary shafts structures are seen within cortical vesicles of ciliated regions. Nuclear pores of macronucleus enlarged apparently, reduced in number, and, chromatin attached on the inner membrane of these nuclear pores.