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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 998

Richard D. Allen; Food vacuole membrane growth with microtubule-associated membrane transport in Paramecium. J.Cell Biology 63:904-922, 1974

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Evidence from a morphological study of the oral apparatus of Paramecium caudatum using electron microscope techniques have shown the existence of an elaborate structural system which is apparently designed to recycle digestive-vacuole membrane. Disk-shaped vesicles are filtered out of the cytoplasm by a group of microtubular ribbons. The vesicles, after being transported to the cytostome-cytopharynx region in association with these ribbons, accumulate next to the cytostome-cytopharynx before they become fused with the cytopharyngeal membrane. This fusion allows the nascent food vacuole to grow and increase its membrane surface area. The morphology of this cytostome-cytopharynx region is described in detail and illustrated with a three-dimensional drawing of a portion of this region and a clay sculpture of the oral apparatus of Paramecium. Evidence from the literature for the transformation of food vacuole membrane into disk-shaped vesicles both from condensing food vacuoles and from egested food vacuoles at the cytoproct is presented. This transformation would complete a system of digestive vacuole membrane recycling.