Lectin-binding glycoconjugates in Paramecium primaurelia : changes with cellular age and starvation

Abstract

Lectins with different sugar specificities and binding to phagosome-lysosome systems as well as cell surface constituents were used to study glycoconjugate variation throughout culture and clonal life in Paramecium primaurelia, particularly during the transition period from logarithmic to stationary growth phase and in relation to clonal decline, respectively. These lectins include Griffonia simplicifolia agglutinin II (GS II), Ricinus communis agglutinin (RCA120). Arachis hypogea agglutinin (PNA), succinyl concanavalin A (succinyl-con A), and Triticum vulgaris agglutinin (WGA). The labeling obtained varies both according to the lectin used and to the culture and clonal age of the cells. Negative results were obtained in logarithmic growth phase cells and in clonal young cells by using lectin GS II. Conversely, lectins RCA120 and PNA bind to the cell surface, the oral region as well as cilia, and do not undergo modifications with culture or clonal age and after permeabilization. WGA binds to constituents of the cell surface, trichocyst tips, food vacuoles, the oral region, and cilia but the extent of labeling decreases as culture age increases; during clonal decline, cells show the same labeling pattern as starved cells. Finally, the lectin succinyl-con A shows a large amount of binding sites on the cell surface, on trichocyst tips, and in the oral region of logarithmic-phase cells, whereas the number of sites decreases in late stationary phase. The data obtained partly differ from those reported in the literature and the differences can be attributed to the culture conditions and species examined. Nevertheless, the assumption that a rearrangement of some glycoconjugates of membrane throughout culture and clonal life of Paramecium is confirmed.

Cell differentiation and morphogenesis in the colony-forming choanoflagellate Salpingoeca rosetta

“…Plant-based lectins, which bind specifically and with high affinity to distinct sugar groups, have been used as cell surface probes for cell differentiation in animals and unicellular eukaryotes (Allen et al, 1988; Falk et al, 1994; Lueken et al, 1981; Ramoino, 1997; Ramoino et al, 2001). We found that one lectin, wheat germ agglutinin (WGA), selectively labels the plasma membrane of all cells in rosette and chain colonies at equal levels (Fig.…”

Cell surface lectin-binding glycoconjugates on marine planktonic protists

“…4a and b). In contrast, Ramoino (1997) reported intense binding of PNA to the cilia and cell surface of Paramecium primaurelia . PNA also binds to a number of species belonging to the dinoflagellate genera Gymnodinium , Prorocentrum and Alexandrium (Cho, 2002).…”

“…1). Studies by Allen et al (1988) and Ramoino (1997) demonstrate that formaldehyde and paraformaldehyde also permeabilize ciliate pellicles. To date, fixing protists before lectin incubation has been the most common method of preparation (e.g.…”

“…2d and e). Con A has been reported to bind to a wide variety of dinoflagellate, diatom, coccolithophore, prymnesiophyte and ciliate species, highlighting that mannose/glucose residues commonly occur on the surface of protozoan cells and their prey (Ramoino, 1997; Cho, 2002; Takahashi et al , 2002; Strom et al , 2003; Kremp & Anderson, 2004; Wootton et al , 2006). The lack of Con A binding to Paraphysomonas vestita could potentially be explained by the presence of silicified scales which cover the cell surface of this species.…”

“…In order to determine the relevance of carbohydrate–protein interactions within microbial food webs, a suitable protocol for studying the presence and localization of cell surface sugar moieties is required. There are a wealth of studies investigating lectin binding to carbohydrates within a broad range of free‐living protists, including ciliates, dinoflagellates, diatoms and coccolithophores (Costas & Rodas, 1994; Ramoino, 1997; Cho, 2002; Takahashi et al , 2002; Strom et al , 2003; Kremp & Anderson, 2004; Wilks & Sleigh, 2004). The method of preparation in the majority of studies, however, causes permeabilization of cell walls, resulting in lectins binding to internal cell structures in addition to those on the cell surface (Lueken et al , 1981; Allen et al , 1988; Ramoino, 1997).…”