[Light- and electron-microscopic study of pelobiont Pelomyxa secunda (Gruber, 1884) comb. nov. (Archamoebae, Pelobiontida)].

Morphology of a pelobiont Pelomyxa secunda (Gruber, 1884) comb. nov. was investigated at light- and electron-microscopical levels. Locomotive forms are elongated or cigar-shaped. The size of active forms varies from 200 to 300 µm. Larger individuals (up to 400 µm) are not able to directed movement. Organism can produce short, usually finger-shaped hyaline pseudopodia at the frontal side or laterally. The cell coat is represented by amorphous glycocalix, up to 300 nm in thickness. A thin periphery cytoplasmic zone is deprived of any organelles, vacuoles, endocytobionts and other inclusions and separated from main cytoplasm by a layer of arranged microfilaments. P. secunda is multinucleate organism; nuclei are of granular type. The nucleolar material is represented by two forms of discrete structures differing in size and electron density. Two or three layers of short microtubules organized in the parallel arrangement are associated with outer side of the nuclear envelop. P. secunda possess two types of obligate prokaryotic endocytobionts lying in individual symbiontophoric vacuoles. Undulipodia, kinetosomes and root microtubular derivatives are not observed in P. secunda cells as well as any developed cytoplasmic microtubular cytoskeleton.

[Comparative morphology of the subphilum Conosa Cavalier-Smith 1998].

Comparative analysis of archamoebae and slime molds morphology revealed that this organisms have a marked similarity in organization of locomotive forms, structure of glycocalix and also in organization of nuclear and flagellar apparatus. A possible scheme of formation the modern diversity of Conosa group was proposed.

[Morphology of Mastigamoeba aspera Schulze, 1875 (Archamoebae, Pelobiontida)].

The morphology of Mastigamoeba aspera, a type species of the genus Mastigamoeba Schulze, 1875, has been investigated at the light- and electron-microscopical level. Motile individuals are oval or peach-shaped. Motile flagella is situated at the anterior end of uninucleate cells. During locomotion, the surface of mastigamoebes forms many conical or finger-shaped hyaline pseudopodia, wereas bulbous uroid is often formed at the posterior end of the cell. Micropopulations of M. aspera consist of uninucleate flagellate forms as well as multinucleate aflagellate ones. There is a thick layer ofglycocalix on the cell surface where many rod-shaped bacterial ectobionts live. The nucleus is vesicular with spherical central nucleolus. The flagellar apparatus of M. aspera is connected with nucleus to form so called kariomastigont. A single kinetosome is associated with many radial microtubules and a lateral root. A distinct microtubule organization centre (MTOC) is situated at the basal part of the kinetosome. Microtubules of the nuclear cone are connected with the MTOC. This microtubules take part in the formation of kariomastigont. The axoneme has a standart set of microtubules 9(2)+2. Digestive vacuoles are the main component of the cytoplasm of M. aspera. Beside, many light-difracted granules and glycogen bodies were found in the cells. Mitochondria, dictyosomes of the Golgi apparatus and microbodies were not revealed in the cytoplasm of M. aspera.