No growth cycle in physarum

Abstract The activities of a number of enzymes have been determined in growing plasmodia of Physarum polycephalum at 1 h intervals during the naturally synchronous nuclear division cycle. The enzymes selected represent the main pathways of energy metabolism, they do not require posttranslational steps for activation, nor are they directly involved in DNA replication, mitosis or differentiation. We found constant activity levels for all enzymes tested and discuss the lack of endogenous oscillations in the synthesis of the corresponding proteins with respect to the growthcycle concept.