title: Visualization of calcium-binding sites at plasma membrane of shock-frozen Acanthamoeba cells.
abstract: Electron-dense deposits appear at the protoplasmic side of plasma membrane in Acanthamoeba log-phase cells when fixed either with glutaraldehyde or formaldehyde supplemented with Ca2+. Similar deposits appear when the cells are preloaded with Ca2+ and thereafter shock-frozen and prepared for electron microscopic examination by freeze-substitution technique. This suggests that their formation reflects the presence of a physiologically active system involved in capturing excess of inflowing calcium.
mesh_terms: D000656:Amoeba / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000648:ultrastructure; D005615:Freezing; D008854:Microscopy, Electron; D013194:Staining and Labeling
chemical_list: D002118:Calcium