Dictyostelium discoideum is a simple but fascinating eukaryotic microorganism,
whose natural habitat is deciduous forest soil and decaying leaves, where the
amoebae feed on bacteria and grow as independent single cells. Exhaustion of the
bacterial food source triggers a developmental program, in which up to 100,000
cells aggregate by chemotaxis towards cAMP. Morphogenesis and cell differentiation
then culminate in the production of spores enabling the organism to survive
unfavorable conditions. Dictyostelium offers unique advantages for studying fundamental
cellular processes with the aid of powerful molecular genetic, biochemical,
and cell biological tools. These processes include signal transduction,
chemotaxis, cell motility, cytokinesis, phagocytosis, and aspects of development
such as cell sorting, pattern formation and cell type differentiation. Recently, Dictyostelium
was also described as a suitable host for pathogenic bacteria in which
one can conveniently study the process of infection. In addition, Dictyostelium has
many of the experimental conveniences of Saccharomyces cerevisiae and is probably
the best experimentally manipulatable protozoan, providing insight into this
diverse group of organisms, which includes some of the most dangerous human
parasites.