The catalase and superoxide dismutase genes are transcriptionally up-regulated upon oxidative stress in the strictly anaerobic archaeon Methanosarcina barkeri.
Methanosarcina barkeri is a strictly anaerobic methanogenic archaeon, which can survive oxidative stress. The oxidative stress agent paraquat (PQ) suppressed growth of M. barkeri at concentrations of 50-200 microM. Hydrogen peroxide (H2O2) inhibited growth at concentrations of 0.4-1.6 mM. Catalase activity in cell-free extracts of M. barkeri increased about threefold during H2O2 stress (1.3 mM H2O2, 2-4 h exposure) and nearly twofold during superoxide stress (160 microM PQ, 2 h exposure). PQ (160 microM, 2-4 h exposure) and H2O2 (1.3 mM, 2 h exposure) also influenced superoxide dismutase activity in cell-free extracts of M. barkeri. Dot-blot analysis was performed on total RNA isolated from H2O2- and PQ-exposed cultures, using labelled internal DNA fragments of the sod and kat genes. It was shown that H2O2 but not PQ strongly induced up-regulation of the kat gene. PQ and to a lesser degree H2O2 induced the expression of superoxide dismutase. The results indicate the regulation of the adaptive response of M. barkeri to different oxidative stresses.
Brioukhanov
Andrei L
AL
Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Überlandstrasse 133, 8600 Dübendorf, Switzerland.|Department of Microbiology, Biological Faculty, Lomonosov Moscow State University, Vorob'evy Hills 1/12, 119992 Moscow, Russia.
Netrusov
Alexander I
AI
Department of Microbiology, Biological Faculty, Lomonosov Moscow State University, Vorob'evy Hills 1/12, 119992 Moscow, Russia.
Eggen
Rik I L
RIL
Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Überlandstrasse 133, 8600 Dübendorf, Switzerland.
D000693:Anaerobiosis; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D019848:Gene Expression Regulation, Archaeal; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017021:Methanosarcina barkeri / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D010269:Paraquat / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D016877:Oxidants; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D010269:Paraquat