INDUCTION OF SYNCHRONOUS DIFFERENTIATION (ENCYSTMENT) IN PHYSARUM-POLYCEPHALUM MYXAMOEBAE

Encystment of Physarum polycephalum myxamoebae, grown under nearly identical physiological conditions as plasmodia is induced by transfer to a salts medium containing 0.5 M mannitol or mannose. After 24 h induction approximately 50% of amoebae had differentiated to cells which were identified to be young cysts by light and electron microscopy. Several other polyols, sugars, biogenic amines, and a starvation period from 24 h to one week caused no reproducible cyst formation. In contrast to the formation of dormant forms in the plasmodial stage of the life cycle, the induction of cysts and their germination to amoebae are not inhibited neither by actinomycin C nor by cycloheximide. In addition, the isoenzyme spectra of aminopeptidases and acid proteases remain nearly identical in growing and differentiating amoebae. © 1979 Springer-Verlag.