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Amoeba borokensis CCAP 1503/7.

Inverted NikonDiaphot, phase contrast.
Locomotive forms, nucleus and uroidal structures.

Photo: A.Smirnov

Amoeba borokensis Kalinina, Afon'kin, Gromov, Khrebtukova & Page, 1987
CCAP 1503/7

  • Lentgh in locomotion 210-545 mkm (average about 370 mkm). Majority of amoebae are polypodial (polytactic) under favourable conditions, with small minority orthotactic. Floating form of radial type; several thick pseudopodia of unequal lenght radiate from irregular central mass of the granuloplasm. Most of crystals rectangular plates.

  • Nucleus of granular type, a compress sphere or ovoid, occasionally almost discoid, but not concave, 23-37 mkm in diameter (average 29 mkm).

  • Surface coat consists of crinkly filaments 200-250 nm above the plasma membrane, more fine that in A. proteus; mitochondrial heteromorphism is known; honeycomb-like nuclear lamina (Kalinina et al., 1987).

  • This species is generally smaller and less wrinkled than A. proteus. Identification require special attention. As far as I know, the only record of this species is from the original isolation site.TEM of the cell coat is obligate for correct identification; nuclear DNA content of this species is about half that of A. proteus (Kalinina et al., 1987). Incompatible with other species of the genus Amoeba by nuclear transplantation.

  • Freshwater, North-Western Russia. Cultivation: PJ medium + Tetrahymena. Can be maintained for some time in PJ + wheat (rise) grain, in presence of Tetrahymena.

  • The type strain is available from Culture Collection of Algae and Protozoa, CEH Windermere, UK.

  • Basic references for identification:
    • Kalinina L.V., Afon'kin S.Yu., Gromov D.B., Khrebtukova I.A. and Page F.C. 1987. Amoeba borokensis n.sp., a rapidly dividing organism especially suitable for experimental purposes. Arch. Protistenk. 132: 343-361.
    • Page F.C. 1988. A new key to freshwater and soil gymnamoebae. FBA, Ambleside. 122p.
    • Page F.C. 1991. Nackte Rhizopoda. in: Protozoenfauna, b.2. Gustav Fisher, Stuttgart. 3-172.
    Note that the keys by Page from 1988 and 1991 harbour slightly different sets of illustrations for this species.

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