Contribution of the myeloperoxidase-dependent oxidative system to host defence against Cryptococcus neoformans.

The in vivo contribution of reactive oxygen species produced by neutrophils against Cryptococcus infection is not widely recognized. Myeloperoxidase (MPO) is a neutrophil-specific enzyme that catalyses the production of hypohalous acids such as HOCl from H2O2. This study investigated the role of MPO in immunological defence against Cryptococcus neoformans in an MPO-deficient (MPO-/-) mouse model.

In vivo role of myeloperoxidase for the host defense.

Myeloperoxidase (MPO) is located within neutrophils capable of producing HOCl. To define the in vivo role of MPO, we have generated MPO-knockout (MPO-KO) mice. The mice without MPO developed normally.

The rpoZ gene, encoding the RNA polymerase omega subunit, is required for antibiotic production and morphological differentiation in Streptomyces kasugaensis.

The occurrence of pleiotropic mutants that are defective in both antibiotic production and aerial mycelium formation is peculiar to streptomycetes. Pleiotropic mutant KSB was isolated from wild-type Streptomyces kasugaensis A1R6, which produces kasugamycin, an antifungal aminoglycoside antibiotic. A 9.

Critical role of myeloperoxidase and nicotinamide adenine dinucleotide phosphate-oxidase in high-burden systemic infection of mice with Candida albicans.

Oxygen metabolites generated by myeloperoxidase (MPO) and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase contribute to microbial killing by phagocytes. To compare the importance of the 2 enzymes for host defense, MPO-deficient (MPO(-/-)) mice and NADPH-oxidase-deficient mice with chronic granulomatous disease (CGD mice) were intraperitoneally infected with 3 different doses of Candida albicans, and their infection severity was analyzed. CGD mice had increased mortality and exhibited increased tissue fungal burden in a dose-dependent manner, whereas normal mice showed no symptoms.