COMPUTER-AIDED 3-DIMENSIONAL RECONSTRUCTION OF THE FREE-LIVING PROTOZOAN BODO SP (KINETOPLASTIDA, BODONIDAE)

Computer aided three-dimensional (3-D) reconstructions of Bodo sp., a free-living kinetoplastid, were made from ultrathin (100 nm) and semit hin (200 nm) serial sections, which were observed by transmission elec tron microscopy. Organelles and membrane systems were digitized into a computer and three-dimensional images were generated using the SYNU s oftware package. It was observed that the internal disposition of stru ctures like the contractile vacuole, the Golgi complex, the mitochondr ion, and the nucleus maintain a constant relationship relative to each other and to the cytostome and flagellar pocket. The Golgi complex an d the contractile vacuole elements are not apparently connected. The c ontractile vacuole fills a significant volume in the cell. Volume alte rations occurring during systole/diastole cycles of the contractile va cuole are compensated by cytoskeletal adaptations. There is a subpelli cular microtubule-free area adjacent to the contractile vacuole. Morph ological evidence indicates that the flagellar pocket may not be the o nly site of vacuolar content elimination. A better view of the cytoske leton was obtained in detergent-extracted cells, where a set of curved microtubules was observed separating the flagellar pocket from the cy tostome and surrounding the cytopharynx.