REGULATION OF PROTEIN AND CELLULASE EXCRETION IN THE RUMINAL FUNGUS NEOCALLIMASTIX-FRONTALIS EB188

Extracellular protein and cellulase excretion secretions were studied in the ruminal fungus Neocallimastix frontalis EB188. Cellulase assay and polyacrylamide gel electrophoresis was used to characterize protein excretion patterns caused by media switches of established cultures. Glucose switch medium caused the excretion of low levels of cellulase and increased amounts of low-molecular-weight proteins. Cellulose switch medium caused the excretion of high levels of cellulase and increased amounts of high-molecular-weight proteins. Several proteins were excreted uniquely or in greater amounts in cellulose cultures than in glucose cultures. Distinct protein excretion patterns suggested that regulation of cellulase was a closely controlled process in ruminal fungi. © 1990 Springer-Verlag New York Inc.