Pectolytic, cellulytic and proteolytic activities expressed by cultures of Endothia parasitica, and inhibition of these activities by components extracted from Chinese and American chestnut inner bark

Three classes of enzymatic activity were expressed in cultures of virulent and hypovirulent strains of Endothia parasitica. Polygalacturonase, cellulase, and protease activities accumulated in liquid cultures. Polygalacturonase activity was also detected in samples from active cankers resulting from infection by virulent strains of E. parasitica. The acidification of liquid media, as well as chestnut tissue in advance of growing mycelium, was determined and compared with the pH optima for the three enzyme activities. Additionally, polyphenolic extracts from Castanea mollissima were found to be more effective in eliminating polygalacturonase activity than were extracts from Castanea dentata. A specific inhibitor of polygalacturonase activity was also isolated. Polygalacturonase inhibitory activity extracted from C. mollissima inner bark was found to be more than twice as potent as the same activity extracted from C. dentata inner bark.