Paradermamoeba levis Smirnov & Goodkov 1994


Paradermamoeba levis 1-4, 10-11: locomotive; 5: cell in "non-directed" movement; 6: floating form; 7,12: resting cell; 8: binucleate cell (alive); 9: binucleate cell (stained preparation);
Scale bar: 20 mkm



Paradermamoeba levis 1-2: nucleus; 3,5: nuclear envelope contacting with RER; 4: mitochondria; 6-7: cell surface; 8: dyctiosome
Scale bar: 500 nm.

Paradermamoeba levis 1-3: strange inclusions in the cytoplasm, resembling discharged microsporidian spores; 4: fibrillar material in the cytoplasm; 5: food vacuoles 6: contractile vacuole.

Scale bar 500 nm.
  • Locomotive form flattened, oblong. Lateral parts of the body usually are more flattened than the axial part, but sometimes these flattened extensions are not pronounced or disappear. The frontal zone of hyaloplasm has long lateral extensions toward the posterior end of the body. The length of locomotive amoeba ranges from 23 to 53 mkm (average length 35-46 mkm). The breadth is about 6-18 mkm. Average length/breadth ratio (L/B) is 3,5 - 3,9.
  • Floating form is of the radial type. There is a central mass of granuloplasm with 5-7 thick, blunt, hyaline pseudopodia often of unequal length; the longest ones are 4-5 times longer than the diameter of the central granular mass.
  • The nucleus is of the vesicular type. In living specimens it measures 2,3-5,7 mkm in diameter (average diameter is 4 mkm); the central endosome is about 1,5-2,9 mkm. The number of nuclei per
  • cell is variable. Among 46 simultaneously inspected amoebae there were 32 with one nucleus, 12 with two nuclei and 2 with three nuclei. When an amoeba contains two nuclei, they are unequal in size and often closely associated with each other. In living specimens such associations often look like one nucleus with two endosomes, but the presence of two separate nuclei may be confirmed in stained preparations. It should be mentioned, that sometimes nearly all amoebae in a culture contained two nuclei, but during other periods only a few binucleate specimens were observed.
  • The amoeba has one contractile vacuole, which is generally situated at the posterior part of the body. We never observed crystals in the cytoplasm. Cysts are unknown.
  • At the ultrastructural level the nucleus of this species has central non-homogenous nucleolus, sometimes with the central lacuna. The cell coat consists of a spiral glycostyles (like in P.valamo), but P.levis lacks the distinct straight terminal structures on the distal end of glycostyles. The total thickness of the cell surface is about 220 nm; the diameter of the helices is about 90 nm, and they form 3-4 turns. Dictyosomes and elongate mitochondria of this species have routine structure. Conspicuous feature of P.levis is the regular presence of the cytoplasmic inclusions of unclear nature.

    References
    1. Smirnov A.V., Goodkov A. V. Freshwater Gymnamoebae with a new type of surface structure - Paradermamoeba valamo and P.levis n. sp. (Thecamoebidae), and notes on the diagnosis of the family. // Acta Protozoologica, 1994. 33: P.109-115.

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