Effect of sugars on early biochemical events in development of Dictyostelium discoideum.

Abstract

Metabolizable sugars blocked development of the slime mold D. discoideum; the same sugars also inhibited the formation of contact sites A, of membranal 3'':5''-cyclic AMP (cAMP)-binding sites, and of total cAMP phosphodiesterase (3'':5''-cyclic-nucleotide phosphodiesterase; EC 3.1.4.17; 3'':5''-cyclic-nucleotide 5''-nucleotidohydrolase). These inhibitory effects of the sugars on the synthesis of cellular components, required for the aggregation of developing amoebae, were paralleled by an inhibition of the accumulation of cAMP which normally accompanies development. The inhibition by sugars was overcome partially by pulsing the amoebae with nanomolar concentrations of cAMP only after the amoebae had acquired cAMP-binding sites. Apparently metabolizable sugars inhibit development by blocking the formation of cAMP, and conversely, development in D. discoideum may be related to the energetic state of the cell.