portrait & nucleus

Description:

Description: Amoeba with a pellicle-like surface noticeable by a rather stiff appearance and, in this case, numerous wrinkles. Movement with a tractor-like rolling of the surface.  Size of locomotive form in this specimen 90x70 µm. Hyaloplasm as an antero-lateral crescent. Contractile vacuole located in posterior end of the cell. Nucleus spherical to ovoid, nucleolus of granular texture (see picture in lower right angle), sometimes divided in 2 or 3 fragments. Phase contrast ; nucleus in modified phase contrast. Amoeba was cultured in filtered water from original habitat and fed with Oscillatoria (Cyanobacteria), rests of which are seen in a food-vacuole in the centre.  It is one of the rugose species of the genus as described by Page and one of the typical representatives of Smirnov’s rugose morphotype.  A future zip-file may contain tables showing the peculiar phagocytosis of oscillatoria by Thecamoeba sphaeronucleolus as well as the fusion of two cells followed by encystment and cell division.