Ciliates such as Paramecium have specialized sites for endocytosis and exocytosis. Most of their surface is not available for internalization of membrane because of the underlying alveolar sac system....

A dividing Didinium nasutum. This large ciliate is capable of engulfing Paramecium. It has a thick ectoplasm containing numerous mucocysts embedded in its extensive epiplasm. Its external surface is c...

High resolution image of the cytoproct is the site of spent vacuole defecation on the surface of Paramecium. When closed the cytoproct forms a long narrow wavy ridge along the posterior suture. At its...

Receptor mediated endocytosis is a process in which extracellular molecules are taken into the cell via coated vesicles that pinch from the plasma membrane. In Paramecium the resulting vesicles fuse w...

High resolution image of vesicles and early endosomes under the membranelles of the peniculus of the buccal cavity. Cilia and basal bodies are tangentially fractured in this quick-freeze deep-etch pre...

Quick-freeze deep-etch rotary-shadowed replica of an early endosome with two clathrin-coated evaginations. Presumably these coated pits contain receptors for cargo that will be pinched off from the ea...

Stacks of 4 or 5 kinetodesmal fibers occupy the longitudinal ridges in a cross-sectioned cell. The kds lie along the right side of each ridge (cell’s left side), and as the kds are tapered, the smal...

A view of an early endosome with at least two coated evaginations showing, lies next to the proximal end of a fractured basal body. Other clathrin cages may indicate other evaginations from the same e...

Electric shock causes massive trichocyst discharge and results in a large accumulation of HRP-labeled vesicles at the ectoplasmic/endoplasmic interface (at the level of the internal ends of the undisc...

Nucleoli in a macronucleus of a cell undergoing micronuclear division. The nucleolus appears to have an organized surface layer composed of parallel threads of subunits. These may be developing riboso...