ИСТИНА

The hyperthermophile Thermotoga maritima, although strictly anaerobic bacterium, is not only able to grow in the presence of a low amount of oxygen in the gas phase (up to 0.5% v/v) but could also consume it. T. maritima consumes O2 via a three-component chain involving an NADH oxidoreductase (NRO), a rubredoxin (Rd) and a flavo-diiron protein (FprA). Two ROS scavenging enzymes (neelaredoxin and rubrerythrin) that are encoded by genes clustered with those coding for FprA, NRO and Rd would have provided the ancestor of Thermotogales with a complete set of enzymes dedicated to antioxidative defence. A psychrophilic strictly anaerobic sulfate-reducing bacterium, isolated recently from the oxygenated sub-surface water layer of the Black Sea and belonged to the genus Desulfofrigus, could also consume O2. With the use of degenerated primers the genes coding for rubredoxin : oxygen oxidoreductase (ROO), cytochrome bd ubiquinol oxidase subunit I (CydA) and cytochrome c oxidase subunit I (CoxI) were detected in the genome of Desulfofrigus sp. as well as dfx and rbr genes coding for desulfoferrodoxin and rubrerythrin.