Dictyostelium

Dictyostelium is a genus of social amoebae in the family Dictyosteliaceae. They live in soil and leaf litter, where single-celled amoebae feed on bacteria. When nutrients become scarce, they communicate and coordinate a developmental program that transforms solitary cells into a multicellular organism capable of forming a stalk and spores.

The best-studied member of the genus is Dictyostelium discoideum, though several other species exist. Together, these organisms are classified as Dictyostelia within the Amoebozoa. In the laboratory, they are used as a model to study fundamental cellular processes and development.

During starvation, cells secrete and respond to cyclic AMP (cAMP), organizing into an outward-moving wave that induces chemotaxis and aggregation into a mound. The mound can elongate into a migrating slug, or pseudoplasmodium, which then differentiates into a fruiting body consisting of a supportive stalk and a spore-containing sorus. A sexual cycle can also occur under adverse conditions, forming macrocysts. Cell fate is subdivided into prestalk and prespore lineages, with signaling molecules such as DIF-1 guiding differentiation.

Genomics and genetics are well developed for Dictyostelium. The genome is about 34 megabases with around 12,500 predicted genes. The organism is highly amenable to genetic manipulation, including gene knockouts and reporter constructs, and is supported by dedicated databases and research resources.

Dictyostelium serves as a model for studying cell motility and chemotaxis, signal transduction, endocytosis, and multicellular development. Its relatively simple, controllable system provides insights relevant to higher eukaryotes, including aspects of immune cell behavior and tissue organization. In the lab, they are typically cultured on bacterial lawns and induced to develop by starvation on non-nutrient media.