Preservation of ultrastructure in phosphatidylcholine vesicles by tannic acid and OsO4.
To improve preservation and visualization of membrane structure in artificial phosphatidylcholine vesicles (PC liposomes), the following three fixation formulas including tannic acid (TA) and osmium (OsO4) steps were tested: (1) TA-OsO4, (2) OsO4-TA, and (3) OsO4-TA-OsO4. The TA-OsO4 method, known to stabilize PC against conventional dehydration, was inadequate for characterizing liposome structure because it induced a serious artifact that the liposomes were aggregated and fused. On the other hand, the OsO4-TA method did not cause the artifact but only a dull EM image was obtained for the membrane structure. The best results with egg PC liposomes have been obtained by the OsO4-TA-OsO4 method which gives improved preservation and enhanced contrast of membrane structure.
D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine; D047348:Hydrolyzable Tannins; D008081:Liposomes; D008854:Microscopy, Electron; D008954:Models, Biological; D008968:Molecular Conformation; D009993:Osmium Tetroxide; D010713:Phosphatidylcholines
D047348:Hydrolyzable Tannins; D008081:Liposomes; D010713:Phosphatidylcholines; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; D009993:Osmium Tetroxide; D004134:Dimyristoylphosphatidylcholine