Figure 1. Conditions for growth and development. A Dictyostelium cell (green, in the inner circle) can feed on bacterial particles (red) or by the uptake of liquid medium (brown). In the outer circle different setups for cultivation (yellow background) and development (blue background) are shown and discussed clockwise, starting from top. Cells grow in liquid medium either adhering to the surface of a Petri dish or shaking in an Erlenmeyer flask. Cells in a flask can multiply in a suspension of bacteria. Alternatively, the bacteria are spread to produce a lawn on an agar plate. While the cells grow they consume bacteria, and development commences in areas cleared from food. Finally fruiting bodies are formed (green background). When a sufficient amount of cells is spread on a filter or agar surface devoid of nutrients, fruiting bodies come up synchronously. Starved cells in suspension aggregate but do not proceed further in development.

Figure 2. Molecular tools for genetic manipulation of Dictyostelium. The options for investigating the function of a given gene (centre) are illustrated, clockwise from top. Using a promoter (P) and a terminator (T) of choice, fusions with green fluorescent protein (GFP) can be expressed. Alternatively, the GFP open reading frame may be inserted into the resident gene by homologous recombination (knockin, not shown). The heavy arrow indicates overexpression from a strong promoter in a multicopy vector. Site-specific mutations (red box) can be introduced to express dominant negative or other altered versions of the protein. The function of different domains, for example their ability to rescue a mutant phenotype, can be examined by expression of partial genes, indicated by the two constructs representing the 5¢ and the 3¢ part of the gene. Gene knockdown can be achieved by RNA interference with the expression of an inverted repeat separated by a nonpairing (red) loop or by construction of an antisense gene (inverted arrow). Finally, a gene may be disrupted (knockout) by homologous recombination and insertion of a resistance marker (yellow R).