Cyclic AMP gradient in migrating pseudoplasmodia of the cellular slime mold Dictyostelium discoideum.

Several lines of experimental evidence suggest that an anterior-posterior gradient of cyclic AMP exists in migrating pseudoplasmodia of the cellular slime mold Dictyostelium discoideum, and that this gradient may be responsible for control of the proportions of stalk and spore cells that form during culmination. In experiments reported here, the amounts of cyclic AMP present in the anterior and posterior portions of pseudoplasmodia were measured using a protein binding assay, and the levels obtained normalized to protein and DNA. For a variety of pseudoplasmodia migration conditions examined, the anterior portion was found to contain cyclic AMP concentrations 40 to 70% higher than the posterior portions.