Hydrogen peroxide is a product of oxygen consumption byTrichomonas vaginalis

• Published in: Journal of biosciences 1999-09, Vol.24 (3), p.339-344
• Main Authors: Chapman, Alan, Linstead, David J., Lloyd, David
• Format: Article
• Language: English
• Subjects: Hydrogen peroxide; Oxidative stress; Oxygen; Oxygen consumption
• ISSN: 0250-5991; 0973-7138
• DOI: 10.1007/BF02941248

The amitochondriate sexually-transmitted human parasitic protozoanTrichomonas vaginalis (Bushby strain) grown anaerobically on complex medium containing cysteine and ascorbic acid consumed O^sub 2^ avidly (6.9 μM min^sup -1^ per 10^sup 6^ organisms) with an apparentK ^sub m^ value of 5.1 μM O^sub 2^ : O^sub 2^ uptake was inhibited by O^sub 2^ > 120 μM. Spectrophotometric assays in the presence of microperoxidase (419-407 nm) indicated that H^sub 2^O^sub 2^ was produced and that inhibition by high O^sub 2^ concentrations was again evident. Hydrogenosomes oxidizing pyruvate in the presence of ADP and succinate showed similar patterns of O^sub 2^ consumption, H^sub 2^O^sub 2^ production (33.5 pmol min^sup -1^ per mg protein), and O^sub 2^ inhibition. Cytosolic NADH oxidase gave no detectable H^sub 2^O^sub 2^, whereas the cytosolic NADPH oxidase produced H^sub 2^O^sub 2^ at a rate (43 pmol min^sup -1^ per mg protein) greater than that of hydrogenosomes. These results are discussed in relation to the oxidative stress experienced by the pathogen in its natural habitat.[PUBLICATION ABSTRACT]