Metabolic activity analyses demonstrate that Lokiarchaeon exhibits homoacetogenesis in sulfidic marine sediments
| Autor: | Aurèle Vuillemin, Paula Rodriguez, Volker Mohrholz, Gonzalo V. Gomez-Saez, William D. Orsi, Timothy G. Ferdelman, Ömer K. Coskun, Gaute Lavik |
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| Rok vydání: | 2020 |
| Předmět: |
Microbiology (medical)
Geologic Sediments Immunology Stable-isotope probing Sulfides Models Biological Applied Microbiology and Biotechnology Microbiology Carbon Cycle 03 medical and health sciences Genome Archaeal Genetics Anaerobiosis 030304 developmental biology 0303 health sciences biology 030306 microbiology Chemistry Carbon fixation Cell Biology biology.organism_classification Archaea Anoxic waters Redox gradient Biochemistry Acetogenesis Fermentation Candidatus Metagenomics Energy Metabolism Oxidation-Reduction |
| Zdroj: | Nature Microbiology |
| Popis: | The genomes of the Asgard superphylum of Archaea hold clues pertaining to the nature of the host cell that acquired the mitochondrion at the origin of eukaryotes1,2,3,4. Representatives of the Asgard candidate phylum Candidatus Lokiarchaeota (Lokiarchaeon) have the capacity for acetogenesis and fermentation5,6,7, but how their metabolic activity responds to environmental conditions is poorly understood. Here, we show that in anoxic Namibian shelf sediments, Lokiarchaeon gene expression levels are higher than those of bacterial phyla and increase with depth below the seafloor. Lokiarchaeon gene expression was significantly different across a hypoxic–sulfidic redox gradient, whereby genes involved in growth, fermentation and H2-dependent carbon fixation had the highest expression under the most reducing (sulfidic) conditions. Quantitative stable isotope probing revealed that anaerobic utilization of CO2 and diatomaceous extracellular polymeric substances by Lokiarchaeon was higher than the bacterial average, consistent with higher expression of Lokiarchaeon genes, including those involved in transport and fermentation of sugars and amino acids. The quantitative stable isotope probing and gene expression data demonstrate homoacetogenic activity of Candidatus Lokiarchaeota, whereby fermentative H2 production from organic substrates is coupled with the Wood–Ljungdahl carbon fixation pathway8. The high energetic efficiency provided by homoacetogenesis8 helps to explain the elevated metabolic activity of Lokiarchaeon in this anoxic, energy-limited setting. |
| Databáze: | OpenAIRE |
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