Abstract
AbstractAmmonia oxidizing archaea (AOA) are widespread and highly abundant in nature. Despite their typical aerobic metabolism, they can be abundant in ecosystems where oxygen is scarce. Recent observations revealed that the AOA isolateNitrosopumilus maritimusproduces oxygen and dinitrogen at nanomolar concentrations, upon oxygen depletion through nitric oxide (NO) dismutation. Here, we explore NO dismutation capability in other ammonia oxidizers with different phylogenetic affinities and from different environmental settings. The organisms explored include three marine AOA, one soil AOA and two soil ammonia-oxidizing bacteria (AOB). Upon oxygen depletion all isolates accumulated oxygen. In incubations with15N tracers with ongoing oxygen accumulation, the AOA strainsNitrosopumilus adriaticusandNitrosopumilus viennensisproduced46N2O from nitrite. Transient46N2O accumulation followed by30N2production was detected in the AOA strainsNitrosopumilus piranensisandNitrosopumilussp. CCS1, supporting the earlier observation that NO-dismutation is a common metabolism in AOA, albeit with physiological variations between different strains. An important physiological variable is the capability to reduce N2O to N2. The finding of oxygen production in several AOA, as well as AOB, indicates that this process is widely distributed among the tree of life and adds an explanation for their abundance in oxygen-depleted environments.
Publisher
Cold Spring Harbor Laboratory
Cited by
1 articles.
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