Differentiation of Dictyostelium discoideum cells in suspension culture

Differentiation of Dictyostelium discoideum cells in suspension culture is reported, using a medium containing glucose, albumin, cyclic AMP, EDTA and streptomycin in a phosphate buffer. Production of UDPgalactose:polysaccharide transferase, an enzyme specifically present in prespore cells, and the formation of prespore-specific antigens in more than 60% of the cells, are demonstrated. Differentiation in this medium differs from that previously reported with other suspension systems in that (a) cells form only small, amorphous agglomerates, (b) there is an absolute requirement for cyclic AMP and (c) prior formation of loose cell mounds on a solid substratum is essential for subsequent differentiation in this medium. This last requirement indicates that the differentiation process, giving rise to the prespore-specific enzyme and antigen, can be resolved into two distinct stages, one requiring cell contact on a solid substratum and the other proceeding in small agglomerates incubated in the medium. This medium may be useful for elucidating the role of cyclic AMP and cell contact in slime mould development.