Introduction to Fungi, Third Edition

PROTOSTELIOMYCETES: PROTOSTELID PLASMODIAL SLIME MOULDS
45
Fig 2.4 Dictyostelium discoideum. Development of sorocarp (after Bonner,1944). (a) (c) Aggregation. (d) (h) Migration.
(i) (n) Culmination. C 1
End of aggregation. H 1
End of migration. I 1
Beginning of culmination and stalk formation. J 1
Flattened stage
of culmination. I 1
A later stage of culmination.
some of them cheat only to a degree or only
if altruistic non-cheater strains are present,
whereas others are entirely unable to make a
fruit body in the absence of wild-type amoebae
prepared to form the pre-stalk cells (Dao et al.,
2000; Strassmann et al., 2000). The cheater
phenomenon has raised thought-provoking questions
about the evolution and control of cheating
in social systems (Hudson et al., 2002).
Another interesting aspect involves the mode
of nutrition of Dictyostelium by the phagocytosis
of bacterial cells. Several bacteria pathogenic to
humans and other animals, e.g. Pseudomonas
aeruginosa and Legionella pneumophila, also kill
Dictyostelium upon ingestion (Solomon et al.,
2000; Pukatzki et al., 2002). The observation
that interactions between Dictyostelium amoebae
and phagocytosed bacterial pathogens are similar
to those involving human phagocytes may
stimulate further research on this fascinating
slime mould (Steinert & Heuner, 2005).
2.4 Protosteliomycetes: protostelid
plasmodial slime moulds
This class of organisms (zool.: Protostelea) comprises
14 genera and 35 species (Kirk et al., 2001).