Competition between hydrogen peroxide and nitrate for electrons from the respiratory chains of Thiosphaera pantotropha and Rhodobacter capsulatus

Richardson, David J. ORCID: https://orcid.org/0000-0002-6847-1832 and Ferguson, Stuart J. (1995) Competition between hydrogen peroxide and nitrate for electrons from the respiratory chains of Thiosphaera pantotropha and Rhodobacter capsulatus. FEMS Microbiology Letters, 132 (1-2). pp. 125-129. ISSN 0378-1097

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Abstract

Thiosphaera pantotropha and some strains of Rhodobacter capsulatus express both a periplasmic nitrate reductase and cytochrome c peroxidase when grown under aerobic conditions. Harvested cell suspensions of either species can respire nitrate in the presence of 200 μM O2 (≈ 80% air saturation), at 70-80% of the anaerobic rate. Addition of hydrogen peroxide to such cells causes a 90% inhibition of nitrate reduction under anaerobic or aerobic conditions. The duration of the inhibition is proportional to the concentration of hydrogen peroxide added and can be ascribed to the expression of periplasmic peroxidases that compete with the nitrate reductase for electrons from the respiratory chain. The results reveal a hitherto unrecognised interaction between reactions of denitrification and the reduction of hydrogen peroxide by a periplasmic peroxidase that may have implications for the denitrification in microaerobic environments. The creation of aerobic conditions in bacterial cultures by addition of hydrogen peroxide, and relying on the generation of oxygen by endogenous catalase activity, is a commonly used technique for studying respiratory processes. The observations presented here demonstrate that results derived from such experiments should be interpreted with caution.

Item Type: Article
Additional Information: Funding Information: S.J.F. thanks the SERC for grants GRIE/70627 and GR/H12225 which supported this work. We thank Dr. Ben Berks and Dr. James Moir for helpful discussions.
Uncontrolled Keywords: cytochrome c peroxidase,denitrification,nitrate reductase,nitrate reduction,periplasm,rhodobacter capsulatus,thiosphaera pantotropha,microbiology,molecular biology,genetics ,/dk/atira/pure/subjectarea/asjc/2400/2404
Faculty \ School:
Faculty of Science > School of Biological Sciences
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Depositing User: LivePure Connector
Date Deposited: 14 Jul 2022 17:30
Last Modified: 15 Jul 2022 00:24
URI: https://ueaeprints.uea.ac.uk/id/eprint/86147
DOI: 10.1016/0378-1097(95)00298-J

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