Chaos nobile CCAP 1511/2.
Olympus BH2, DIC
Polytactic and orthotactic locomotive forms,
uroidal structures and nuclei.
Chaos nobile (Penard, 1902) Bovee & Jahn, 1973
Lentgh in locomotion 240-820 mkm (average 450-500 mkm).
Majority of amoebae orthotactic in locomotion (monopodial with distinct
lateral wrinkles), few are polytactic (polypodial).
Crystals are small bipyramids.
This species has very characteristic floating form of irregular
outlines, with branching and re-branching pseudopodia. Each pseudopod
possess a pronounced thickening at the distal end.
6-49 discoid, biconvex nuclei of granular type,
15-23 mkm in diameter (average 18.5 mkm).
Surface coat consists of crinkled filaments,
about 200 mkm in length, radiating from amorphous basal layer.
Overall thickness of the cell coat 176-240 nm. Honeycomb-like
nuclear lamina (Page, 1986).
This species resembles Chaos glabrum very much. The
major LM difference is the floating form. Chaos nobile has a
very specific floating form with branching and re-branching
pseudopodia, bearing a characteristic thickenings at the proximal ends
(see Page, 1988). In Chaos glabrum the floating form is
radial, like in Amoeba proteus. Another difference is the
ultrastructure of the cell coat. TEM of the cell coat is obligate for
identification, keep in mind that filaments in proteus-like
amoebae may coagulate under the EM fixation.
The culture is available from the from the
Collection of Algae and Protozoa, CEH Windermere, UK)
Freshwater, Europe, North America.
Cultivation: MP + Colpidium colpoda. May be
maintained for some time in PJ +
wheat (rise) grain, in presence of small ciliates and
Basic references for identification
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.
Smirnov A.V. and Goodkov A.V. 1997. Description of a large,
multinucleate lobose amoeba Chaos glabrum n.sp.
(Lobosea, Amoebidae), with notes on the diagnosis of the genus
Chaos. Acta Protozool. 36: 227-233.
Note that the keys by Page from 1988 and 1991 harbour slightly
different sets of illustrations for this species.
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