Resting Cyst Wall Glycoproteins Isolated From Two Colpodid Ciliates Are Glycine‐rich Proteins

Abstract

Two glycoproteins bands isolated from the cyst wall protein pattern of two colpodid ciliates, Colpoda inflata (gp46CI) and Colpoda cucullus (gp46CC) were analysed for their amino acid composition. Both glycoproteins are very rich in glycine and have a relatively high hydrophobicity, containing additionally many leucine and alanine residues. Their high degree of similarity is both quantitative and qualitative. Compared with just two previously published reports, their amino acid compositions are similar to those found in the hydrolysed cyst wall total proteins from the ciliates C. steinii and Paraurostyla spp. The amino acid composition corroborates that they are indeed glycoproteins, because asparagine, an amino acid residue suitable for the attachment to N-acetylglucosamine by its amide group (N-glycan), is abundant in both proteins. We discuss our data in relation to other glycine-rich proteins and a comparison with amino acid composition protein databases is carried out.

Analysis of Fruiting Body Development in the Aggregative Ciliate Sorogena stoianovitchae (Ciliophora, Colpodea)

“…The stalk material in Sorogena has a fibrous nature, similar to that of the cyst wall. In fact, cyst walls in a few Colpoda species examined so far consist of glycine‐rich proteins (Izquierdo, Martin‐Gonzalez, and Gutierrez 2000; Tibbs 1982), and the fruiting body stalk of Sorogena is also made from glycine‐rich protein (Blanton, Warner, and Olive 1983). The similarity between the cyst wall and the stalk is strongly suggestive of a common origin for both materials.…”

Can Colpoda travel across oceans? Salinity tolerance of resting cysts may enable global dispersal of the species.

“…The cyst walls of ciliates also contain carbohydrates (24), and the presence of chitin has been inferred in some ciliates following chitinase digestion (24, 63, 64). However, Colpoda species ( C. cucullus, C. steinii ) have been reported to test negative for chitinase digestion, indicating the absence of chitin (24,47,63). On the other hand, we confirmed the presence of chitin in ectocysts by chemical analysis in this study.…”

Differentially Expressed Genes During Fruiting Body Development in the Aggregative Ciliate Sorogena stoianovitchae (Ciliophora: Colpodea)

“…Considering the prediction and the timing of expression, 17L could be secreted into the extracellular matrix by exocytosis at the secretion stage of the mucous matrix, or the later stage of stalk elongation. With reference to the latter stage, the fruiting body stalk of S. stoianovitchae (Blaton et al 1983) and cyst wall of other ciliates (Izquierdo, Martin‐Gonzalez, and Gutierrez 2000; Tibbs 1982) are both composed of glycine‐rich proteins. Both Colpoda and S. stoianovitchae are colpodid ciliates and form resting cysts so that the stalk of S. stoianovitchae and cyst walls of Colpoda are likely to have a common origin.…”