Polypeptide compositions of amoebae of the cellular slime mould Dictyostelium discoideum separated by partitioning during development.

Amoebae of the cellular slime mould Dictyostelium discoideum at 8 h or 10 h development were separated into two populations by countercurrent distribution in a dextran-poly (ethylene glycol), two-phase system. Two-dimensional, polyacrylamide-gel electrophoresis was then used to separate the polypeptides from the populations of amoebae. The two populations of amoebae at 8 h development differed 9n polypeptide composition as did the populations separated at 10 h development. This confirms that cell differentiation is initiated in D. discoideum prior to 8 h development.