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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 898

Cicily Chapman-Andresen and Jytte Reichstein Nilsson; Studies on endocytosis in amoebae. The distribution of pinocytically ingested dyes in relation to food vacuoles in Chaos chaos. II. Electron microscopic observations using alcian blue. Compt.Rend.Trav.Lab.Carlsberg 36(10):189-206, 1967

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An electron microscopic study was made of the digestive cycle in Chaos chaos after feeding with Stentor polymorphus; the fine structural details of the cytoplasm and organelles adjacent to the food vacuoles in normal amoebae were compared with corresponding regions in amoebae which had pinocytosed alcian blue solutions. Shortly after ingestion of the ciliate prey an accumulation of small (ca. 2-3 um) vesicles was found on the cytoplasmic side of the food vacuole membrane. Quantitative data showed that these vesicles were similar in size and number in control and dye-treated cells, while in the latter, observations on 1 u Epon sections by light microscopy revealed that a certain proportion of the vesicles contained dye granules. Similar vesicles were always found in the supranuclear zones of amoebae centrifuged in vivo, again a certain proportion of the vesicles in dye treated amoebae contained dye granules. These vesicles are considered to be secondary lysosomes formed by fusion of the pinocytic vesicles with a primary, enzyme-bearing organelle, which may be identical with the small (ca. 0.2 um) vesicles, which have a slightly dense content, and were found in the supranuclear zone of centrifuged amoebae, and also around older food vacuoles. This hypothesis is supported by earlier light microscopic observations on the distribution of dyes and of acid phosphatase activity under similar experimental conditions.