Aspergillus fumigatus catalases: cloning of an Aspergillus nidulans catalase B homologue and evidence for at least three catalases

The presence of catalases in the water soluble fractions of three Aspergill us fumigatus strains was investigated using nondenaturing and denaturing po lyacrylamide gel electrophoresis and Western analysis. Using non-denaturing polyacrylamide gel electrophoresis and staining for catalase activity, thr ee separate catalases were identified. An A. fumigatus catalase gene (catB) was cloned from genomic DNA using the Aspergillus niger catR gene as a pro be. Polyclonal antibodies were raised to a glutathione S-transferase-CatB f usion product expressed in Escherichia coli. Western analysis indicated tha t, under denaturing conditions, the polyclonal antibody recognised a 90-kDa band and under non-denaturing conditions, two separate bands were identifi ed. These results indicate that A. fumigatus in addition to CatB, produces at least two other catalases, one of which is similar in size to CatB. The polyclonal antibody was also used to observe catalase expression in mice, e xperimentally infected with A. fumigatus. Staining was observed heterogeneo usly throughout the fungal hyphae. This result indicates that catalase is p roduced by A, fumigatus during invasive aspergillosis. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. A ll rights reserved.