protozoa have long been portrayed as a "missing link" between
the animals and plants, but perhaps because they are so manifestly
motile, they have tended to be classified as animal more than vegetable
(thus the name protozoa!). The truth is of course much more muddy
and uncertain, as is the case for most issues. Many protists (e.g.
unicellular algae) are obviously affiliated to the plants than
plants, while others (e.g. most amoebae) are considered animal.
However, the "amoebae" are an eclectic group of organisms
connected only by a common life style. It is my contention that Acanthamoeba
are more closely related to plants than animals, but admittedly this argument
is of little actual consequence. However, an understanding of the
basic biology of Acanthamoeba is of course relevant since the
genus is significant to the micro-ecology of soil (and therefore
agriculture) and human health.
is probably the best current tool for the determination of
intra-organism relationships (with a few caveats). These analysis
tend to place Acanthamoeba close to the green algae and plants,
however because Acanthamoeba (well, A. castellanii Neff
strain, at least, the others are not so well characterised) is so G and
C rich, this may be problematic for such analysis. Other
approaches are therefore needed to back this up.