discoideum

Discoideum, correctly known as Dictyostelium discoideum, is a species of social amoeba in the group Amoebozoa. It is widely used as a model organism in cell and developmental biology because of its simple lifecycle, ease of cultivation, and genetic tractability. In laboratory settings, it is studied for basic processes such as chemotaxis, cell movement, and development, as well as for insights into multicellularity.

In nutrient-rich environments, Dictyostelium discoideum exists as unicellular, phagocytosing bacteria. When food becomes scarce, individual cells release and sense cyclic AMP (cAMP) as a chemoattractant, coordinating a rapid aggregation into a multicellular structure. The aggregate develops into a migrating slug (pseudoplasmodium), which then culminates into a fruiting body consisting of a stalk and a head containing resilient spores. Under favorable conditions, spores germinate and resume unicellular growth.

Genetically, the organism has a fully sequenced genome of about 34 megabases and roughly 12,500 predicted protein-coding genes. It is highly amenable to genetic manipulation, with established methods for gene disruption, targeted recombination, and the use of reporter constructs. The AX4 laboratory strain is widely used, among others such as NC4, to study development and signaling.

Dictyostelium discoideum serves as a key model for understanding cellular signaling, chemotaxis, and differentiation, as well as the evolution of multicellularity. Its study has contributed to knowledge about cAMP signaling pathways, cell-type specification (prestalk and prespore differentiation), and interactions between eukaryotic cells and bacteria. The organism continues to be leveraged in research on host-pathogen interactions, vesicle trafficking, and innate cellular responses.