Computer aided three-dimensional reconstruction of the free-living protozoan Bodo sp. (Kinetoplastida: Bodonidae)

Abstract

Computer aided three-dimensional (3-D) reconstructions of Bodo sp., a free-living kinetoplastid, were made from ultrathin (100 nm) and semithin (200 nm) serial sections, which were observed by transmission electron microscopy. Organelles and membrane systems were digitized into a computer and three-dimensional images were generated using the SYNU software package. It was observed that the internal disposition of structures like the contractile vacuole, the Golgi complex, the mitochondrion, and the nucleus maintain a constant relationship relative to each other and to the cytostome and flagellar pocket. The Golgi complex and the contractile vacuole elements are not apparently connected. The contractile vacuole fills a significant volume in the cell. Volume alterations occurring during systole/diastole cycles of the contractile vacuole are compensated by cytoskeletal adaptations. There is a subpellicular microtubule-free area adjacent to the contractile vacuole. Morphological evidence indicates that the flagellar pocket may not be the only site of vacuolar content elimination. A better view of the cytoskeleton was obtained in detergent-extracted cells, where a set of curved microtubules was observed separating the flagellar pocket from the cytostome and surrounding the cytopharynx.