Quarterly Journal of Microscopical Science, Vol s2-80, 601-634, Copyright © 1938 by Company of Biologists

Memoirs: The Cytology of Amoeba Proteus ‘Y’ and the Effects of Large and Small Centrifugal Forces

¹ Department of Zoology, Trinity College, Dublin

1. When Amoeba proteus is subjected to high centrifugal force most of the cytoplasmic bodies are thrown out of the cell, so this work was done with the ordinary electrical centrifuge.

2. The stratification of the various cytoplasmic components according to their specific gravity is as follows: the contractile vacuole and the fat, being the lightest, occupy the centripetal position; then there is a layer of cytoplasm followed by mitochondria, neutral-red bodies, crystals, and nutritive spheres. The nucleus occupies a position in between the crystals and the nutritive spheres (Text-fig. 2).

3. The redistribution of the various cytoplasmic components takes place within a few minutes after amoebae have been centrifuged by the electrical centrifuge. Ultra-centrifuged organisms kept in culture solution remain rounded for 10-15 days, and no cyst formation takes place. The crystals and nutritive spheres are reformed; the former seem to be the products of excretion formed by the metabolic activity of the cell.

4. The nutritive spheres contain glycogen as reserve food material, and give positive tests for glycogen with iodine and Best's carmine.

5. There is no evidence that the bodies which stain with neutral red are the homologue of the metazoan Golgi apparatus, although they are pre-existing bodies in Amoeba proteus . The contractile vacuole does not blacken even after prolonged osmication. No certain homologue of the Golgi apparatus was found in Amoeba proteus.

6. Fat and glycogen are two distinct types of storage material present in Amoeba proteus. The former is very well seen with osmic acid, Sudan IV, and Nile blue tests.