Paradermamoeba valamo Smirnov & Goodkov 1993


Paradermamoeba valamo 1-4, 7-9: locomotive; 5: cell in "non-directed" movement; 10: nucleus (stained preparation)
Scale bar: 20 mkm


Paradermamoeba valamo 1-4: locomotive form; 5: cell, changing the direction of movement; 6: cell in "non-directed" movement; 7: rounded inclusions in the cytoplasm
Scale bar: 20 mkm.



Paradermamoeba valamo 1-3: cell surface; 4: tangential section of the cell surface; 5: mitochondria; 6: strange inclusion in the cytoplasm, resembling discharged microsporidian spore; 7: nucleus; 8: dyctiosome.
Scale bar 500 nm.

Locomotive form flattened, oblong, usually lancet-shaped. Amoeba moves flowingly; neither discrete pseudopodia, nor subpseudopodia are formed. Lateral parts of the body are considerably more flattened than the axial part. The frontal zone of hyaloplasm has long lateral extensions toward the posterior end of the body. As a rule these extensions are not longer than 3/4 of the body length, but sometimes they extend along the whole amoeba. Lateral edge of the body commonly is wavy, uneven and the anterior end of the body is rounded. The dorsal surface of the locomotive form is smooth, without any folds or wrinkles. The wide rounded uroidal region sometimes is of a not clearly differentiated morular type; but the uroidal structures are often lacking in locomotion. The length of the locomotive form is 51-107 mkm (the average length is 62 - 76 mkm, depending on the clone); the breadth in the widest part of the body is 16-30 mkm (the average breadth is 19 - 25 mkm). Length/breadth ratio (L/B) is 2,8 - 3,5.
  • The cell has one spherical nucleus with a single central endosome. The nucleus is about 8 mkm in diameter, the endosome is about 5 mkm in diameter (in living specimens).
  • There is one contractile vacuole, which is usually situated in the posterior part of the amoeba body. The most common inclusions in the cytoplasm are small, dark, optically opaque granules, small food vacuoles. We never observed crystals in the cytoplasm of amoebae. Cysts are unknown.
  • The cell coat of this species is about 520 nm of total thickness, and consists of a layer of regularly arranged tightly packed helical-shaped glycostyles. Coils of neighboring helices overlap. Each glycostyle terminates with a hollow straight funnel-shaped structure, which sometimes seems to be pentagonal in cross-section. The length of the spiral part of the glycostyles is about 400 nm and the diameter is about 100 nm; length of the straight terminal part of glycostyles is about 120 nm. Helices form 7-7,5 turns. They are embedded in an unstructured electron-transparent matrix which does not seem to prevent the neighboring glycostyles from moving in relation to each other.
  • The nucleus has very conspicuous structure. Its nucleolus consists of an cord-like arrangements of nucleolar material, which generally form non-homogenous spherical structure. This structure is visible as a central nucleolus with the light microscopy. Dictyosomes and mitochondria of this species are routine for Euamoebida.

    References
    1. Smirnov A.V., Goodkov A.V. Paradermamoeba valamo n.g, n.sp (Gymnamoebia, Thecamoebidae) - freshwater amoeba from the bottom sediments. Zoologicheskij journal. 1993. 72, 2: 5-11.(in Russian, English summary)
    2. 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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