The Organism
Dictyostelium discoideum amoebae grow as separate, independent cells, however, upon starvation they interact and form a multicellular structure (Figure 1). The soil-living amoeba is an excellent organism for the study of the molecular mechanisms underlying differentiation, signal transduction, phagocytosis, cytokinesis, cell motility, host – pathogen interactions and autophagy. Many of these processes resemble those seen in mammalian cells and involved genes can be knocked-out rapidly by targeted homologous recombination. The organism has a short life cycle, is easy to cultivate and can be grown in large quantities which facilitates biochemical analysis. Thus, Dictyostelium is perfectly suited for the analysis of novel as well as evolutionary highly conserved genes using the available armoury of molecular biological techniques.
The composite shows different stages of the D. discoideum developmental cycle in clockwise direction starting at the lower right with the loose aggregate. The final stage is a mature fruiting body (right), that is composed of a mass of spores supported by a stalk. Under standard laboratory conditions the developmental cycle from starving amoebae till the formation of mature fruiting bodies is completed within 24 hours. Scale bar is 250 µm. Courtesy of Drs. M.J. Grimson and R.L. Blanton; modified.