The nature and features of organization of reserve polysaccharides in three Pelomyxa species (Archamoebea, Pelobiontida)

Pelomyxa doughnuta sp. nov. (Archamoebea, Pelobiontida) with an unusual nucleus-glycogen association

We described Pelomyxa doughnuta sp. nov. and examined it with the use of light, electron and immunofluorescence microscopy as well as cytochemical methods. The cells of P. doughnuta sp. nov. are usually binuclear, although cells with one, three or four nuclei are sometimes found in the population. A unique feature of the new species is a dense capsule around the nucleus. It consists of a continuous layer of glycogen 5-20 µm thick. The tubulin cytoskeleton is mainly represented by perinuclear microtubules. P. doughnuta sp. nov. has a filamentous glycocalyx and strongly reduced components of flagellar apparatus. Obligate prokaryotic endocytobionts of two morphotypes are present in the cytoplasm.