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

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.