Amoeba proteus CCAP 1503/9.
Inverted NikonDiaphot, phase contrast.
Locomotive forms, nucleus and uroidal structures.
Amoeba proteus (Pallas, 1766) Leidy, 1878
Lentgh in locomotion 220-740 mkm (average about 425 mkm).
Majority of amoebae are polypodial (polytactic) under favourable
conditions, with small minority orthotactic. Most of crystals
truncate bipyramids. Floating form of radial type; several thick pseudopodia of unequal
lenght radiate from irregular central mass of the granuloplasm.
Nucleus of granular type, discoid, often concave, 22-62 mkm
in diameter (average 40 mkm).
Surface coat consists of crinkly filaments
up to 230 nm above plasma membrane; mitochondrial heteromorphism is known
(Flickinger, 1974); honeycomb-like nuclear lamina (Page, 1986).
Identification of this species is often questionable. Nearly any
large uninucleate amoebae with granular nucleus appears to be
an A. proteus, but not nesessarily is. There are many
species, resembling A. proteus (see Page, 1988, p. 59);
species distinction and sinonimity are still under discussion.
I would advice to assign an isolate to the species A. proteus
only after careful consideration of all arguments "for and
against". TEM of the cell coat (obligate for correct identification)
shows some variability in length and shape of the filaments
even between different recognised strains of this species.
Keep in mind that in many laboratories and in some of culture
collections there are
local isolates named "A. proteus" without proper
investigation. For important studies, like biochemical and
molecular comparison of species and phylogeny I would strongly
advice to use only the isolates with known history of
identification (like these available from the
Collection of Algae and Protozoa, CEH Windermere, UK),
but not a local ones of unknown origin.
Freshwater, Europe, North America (but perhaps, worldwide).
Cultivation: PJ medium + Tetrahymena. Can be
maintained for some time in PJ + wheat (rise) grain, in
presence of Tetrahymena.
Basic references for identification:
Note that the keys by Page from 1988 and 1991 harbour slightly
different sets of illustrations for this species.
- Flickinger C.J. 1974. The fine structure of four "species"
of Amoeba. J. Protozool. 21: 59-68.
- Page F.C. 1986. The genera and possible relationships of
the family Amoebidae, with special attention to
comparative ultrastructure. Protistologica. 22: 301-316.
- 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.
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