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Microbiology. 2002 Apr;148(Pt 4):1129-1142. doi: 10.1099/00221287-148-4-1129.

Redundancy, phylogeny and differential expression of Histoplasma capsulatum catalases.

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Donald W. Reynolds Dept of Geriatrics2, Department of Microbiology and Immunology3, and Department of Biochemistry and Molecular Biology4, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA.
Central Arkansas Veterans Healthcare System, GRECC and Medical Research, VAMC 151/LR, 4300 West 7th St, Little Rock, AR 72205, USA1.
Department of Biology and Center for Genetics and Molecular Medicine, University of Louisville, 139 Life Science Bldg, Louisville, KY 40292, USA5.
Applied Biosystems GmbH, Brunnenweg 13, 64321 Weiterstadt, Federal Republic of Germany6.


Histoplasma capsulatum produces an extracellular catalase termed M antigen, which is similar to catalase B of Aspergillus and Emericella species. Evidence is presented here for two additional catalase isozymes in H. capsulatum. Catalase A is highly similar to a large-subunit catalase in Aspergillus and Emericella species, while catalase P is a small-subunit catalase protein with greatest similarity to known peroxisomal catalases of animals and Saccharomycotina yeasts. Complete cDNAs for the CATA and CATP genes (encoding catalases A and P, respectively) were isolated. The transcriptional expression of the H. capsulatum CATA, CATB (M antigen) and CATP genes was assessed by Northern blot hybridizations on total RNA. Results at the transcript levels for these genes are shown for three conditions: cell morphology (mycelial versus yeast phase cells), oxidative stress (in response to a challenge with H(2)O(2)) and carbon source (glucose vs glycerol). Collectively, these results demonstrated regulation of CATA by both cell morphology and oxidative stress, but not by carbon source, and regulation of CATB and CATP by carbon source but not cell morphology or oxidative stress. A phylogenetic analysis of presently available catalase sequences and intron residences was done. The results support a model for evolution of eukaryotic monofunctional catalase genes from prokaryotic genes.

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