title: Electron microscopic localization of ATPase activity in the cytopharyngeal basket of the ciliate Pseudomicrothorax dubius.
abstract: The cytopharyngeal basket of Pseudomicrothorax dubius is used to ingest filamentous blue-green algae. The basket has three main components: a sheath of microfilaments, bundles of microtubules (the nemadesmata), and ribbons of microtubules. The ribbons of microtubules (nemadesmal lamellae) are adpressed to the food vacuole during ingestion. Cytochemical techniques show that both the lamellae and the microfilamentous sheath possess ATPase activity, but the reaction product appears under different conditions in the two cases. The presence of ATPase activity within the microtubular lattices of the feeding organelle suggests the capacity for active motility. Consequently the basket seems to have two motile systems, one may be used to constrict and dilate the cytopharynx while the other is used in the inward propulsion of the forming food vacuole.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D016798:Ciliophora / Q000201:enzymology* / Q000648:ultrastructure; D004064:Digestive System / Q000201:enzymology / Q000648:ultrastructure; D008854:Microscopy, Electron
chemical_list: D000251:Adenosine Triphosphatases