Genetic dissection of the final exocytosis steps in Paramecium tetraurelia cells: cytochemical determination of Ca2+-ATPase activity over performed exocytosis sites.
In different Paramecium tetraurelia strains the occurrence of a Ca2+-ATPase (or p-nitro-phenylphosphatase) activity at the preformed attachment and exocytosis sites of the secretory vesicles (trichocysts) was analysed by electron-microscopic cytochemistry and X-ray microanalysis. In conjunction with freeze-fracture studies it was found that only those strains, which contain rosette particles, display this Ca2+-ATPase activity (7S, K 40I, nd 9 (18 degrees C), while other strains (nd 6, nd 9 (27 degrees C), tam 38) are devoid of both these characteristics. The presence (absence) of rosette particles and of Ca2+-ATPase activity at the preformed exocytosis sites is correlated with the capability (incapability) of performing exocytosis in these strains. We discuss several possible interpretations of this structure-function correlation.
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002462:Cell Membrane / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005089:Exocytosis; D008854:Microscopy, Electron; D009154:Mutation; D009940:Organoids / Q000201:enzymology; D010247:Paramecium / Q000201:enzymology* / Q000235:genetics / Q000648:ultrastructure
D000252:Calcium-Transporting ATPases