A STUDY OF THE ALKALINE PROTEASES SECRETED BY DIFFERENT ASPERGILLUS SPECIES

Strains from several species of Aspergillus were grown in the presence of soluble collagen, and the major secreted proteins present in the c ulture fluid were examined for proteolytic activity. The possibility o f relatedness among the alkaline proteases secreted by Aspergillus was studied by probing extracts from the various species with polyclonal antisera raised to the isolated alkaline proteases of A.fumigatus and A. oryzae. The pathogenic species A.flavus, A. terreus and A. nidulans hydrolyse collagen and were found to secrete an alkaline protease rel ated to that of Aspergillus fumigatus. In contrast, A. niger and non-p athogenic species such A. glaucus, A. versicolor and A. clavatus were unable to degrade collagen in vitro. These findings suggest a possible pathogenic role for the secreted alkaline proteases of Aspergillus sp ecies.