Ultrastructure, Eneystment and Cyst Wall Composition of the Resting Cyst of the Peritrich Ciliate Opisthonecta henneguyi

Abstract

The cyst wall of Opisthonecta henneguyi has been studied ultrastructurally and cytochemically by light and electron microscopy, as well as by chemical and electrophoretic analyses, to examine the structure of the cyst wall and its composition. The cyst wall consists of four morphologically distinct layers. The ectocyst is a thin dense layer. The mesocyst is the thickest layer and is composed of a compact material. The endocyst is a thin layer like the ectocyst, but less dense. The granular layer varies in thickness and is composed of a granular material. In the resting cyst, kinetosomes of both oral apparatus and trochal band as well as the myoneme system are maintained, and only cilia are resorbed. The sugars present in the cyst wall are predominantly N-acetylglucosamine (90%) and glucose (10%). The mesocyst is composed of chitin, and the endocyst includes glycoproteins and acid mucopolysaccharides. During secretion of the cyst wall, the endocyst and granular layer are secreted from precursors synthesized "de novo". No cytoplasmic precursors of ectocyst and mesocyst have been detected.

Phylogeny and Systematic Position of Zosterodasys (Ciliophora, Synhymeniida): A Combined Analysis of Ciliate Relationships Using Morphological and Molecular Data

“…Opisthonecta henneguyi Bradbury (1965); Calvo et al (2003); Guinea and Fernandez-Galiano (1987); Rosenberg and Grim (1966) replicates of random addition sequence followed by TBR branch swapping, tree-fusing, and sectorial searching (Goloboff 1999). We also searched for the shortest trees by repeated parsimony ratchet searches, each with 200 iterations and upweight/downweight frequencies of 20%.…”

Revealing the Diversity and Quantity of Peritrich Ciliates in Environmental Samples Using Specific Primer-based PCR and Quantitative PCR

“…Most of the free-living peritrichs have a complex life cycle with cyst, free-swimming ( i.e. telotroch), and sessile stages (4, 28, 42). Since only the sessile forms are generally morphologically identifiable, they have been recorded from a variety of environments, e.g.…”

Some ultrastructural observations of the vegetative, resting and excysting ciliate, urostyla grandis (urostylidae, hypotrichida)

“…Many hypotrichous ciliates can differentiate into three types of cysts when they face an adverse environment, and the excystment process can occur when the external environment is ameliorated [1][2][3][4][5] . In kinetosome-resorbing cysts, the cilia and sub-pellicle microtubules are fully resorbed.…”