Extracellular cyclic-amp phosphodiesterase regulation in agar plate cultures of Dictyostelium discoideum.

Extracellular cyclic-AMP phosphodiesterase and the inhibitor of this enzyme is tested in agar plate cultures of two Dictyostelium discoideum wild-type strains and in a mutant which lacks the inhibitor. Under the conditions used, the phosphodiesterase inhibitor is formed in both wild-type strains either before or in an early stage of cell aggregation. During aggregation of one strain the phosphodiesterase activity is extremely low, excluding a necessary function of the enzyme in the aggregation process.