Carboxymethyl cellulase activity in the myxomycete Physarum polycephalum [Fungi]

Carboxymethyl cellulase (CMCase) activity at different life cycle stages in Physarum polycephalum was measured viscometrically in homogenized axenic cultures incubated with CMC. Protein concentrations were determined using the Bio-Rad (Coomassie Blue) assay. Mean activity for several dilutions of the homogenized samples ranged from 318 CMCase activity units/hr/mg protein in old plasmodia to 2423 CMCase units/hr/mg protein in dry spores. Activity in spores and sclerotia was higher than in a vegetative Plasmodium. This CMCase activity level is comparable to that found in some true fungi and suggests that Myxomycetes may utilize cellulose and play a role in the breakdown of plant products.