Paramoeba cells reproduce asexually by binary fission, with mitotic division of the nucleus. Division of the parasome also occurs, either simultaneously with the nucleus or at some time before cytokinesis.
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No electron-microscopic observations have been made on nuclear or
parasomal division. At the light microscope level, mitotic division is of
the "mesomitotic" pattern. The nucleolus and nuclear envelope are no
longer visible after prophase. Spindle microtubules extend from discrete
poles to the chromosomes. No centrioles or other obvious structures are
present at the poles. Cytokinesis normally occurs immediately after the
completion of mitosis. How the parasome divides is unknown; light microscopical observations do not reveal figures that resemble mitosis. The most accessible report of cell division in Paramoeba is that by Page (1970). |
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There are no flagellate stages in the life history. Protistologists in
the late 19th and early 20th centuries, including Schaudinn, the person who first
described Paramoeba, sometimes reported that
flagellate stages were present. These early workers usually did not
have access to monoprotist cultures. The existence of flagellate cells
was refuted by
Hollande (1940, 1980), who found
that the "zooids" seen
by Schaudinn and others were contaminants representing unrelated
protistan species.
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