Ultrastructure of lipid bodies in Tilletia caries teliospores

The ultrastructure of lipid bodies within developing, dormant, and germinating Tilletia caries (DC). Tul. (race T-16) teliospores was studied by freeze-etching and thin-sectioning techniques. When teliospores were prefixed in sodium cacodylate-buffered glutaraldehyde-acrolein for 24 h before further processing, most of the lipid bodies appeared to have a uniformly osmiophilic matrix. Some of these lipid bodies were surrounded by thin electron-dense lines that appeared to be half-unit membranes. Occasionally this membrane seemed to be absent, allowing for a direct interface between lipid and cytosol. Irregular electron-dense patterns were occasionally observed in lipid bodies of developing, dormant, and germinating teliospores. A lamellar substructure with 6- to 10-nm center-to-center spacing was visible in the electron-dense patterns at high magnifications. Irregular fracture patterns were visible in freeze-etch replicas.