FIG 6.

Protease activity is controlled by mtfA. A. fumigatus wild-type, ΔmtfA, complementation (com), and mtfA overexpression (OEmtfA) strains were point inoculated on solid Czapek-Dox medium supplemented with 5% skim milk (Difco), and the cultures were incubated for 4 days at 37°C in the dark. Proteolytic activity was quantified by using an azocasein assay as described in Materials and Methods. The experiment was carried out with three replicates. Standard errors are shown. Different letters above the bars represent significantly different values (P ≤ 0.05).