Publication Date:
2015-10-23
Description:
The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. In marine sediments, AOM is performed by dual-species consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) inhabiting the methane-sulfate transition zone. The biochemical pathways and biological adaptations enabling this globally relevant process are not fully understood. Here we study the syntrophic interaction in thermophilic AOM (TAOM) between ANME-1 archaea and their consortium partner SRB HotSeep-1 (ref. 6) at 60 degrees C to test the hypothesis of a direct interspecies exchange of electrons. The activity of TAOM consortia was compared to the first ANME-free culture of an AOM partner bacterium that grows using hydrogen as the sole electron donor. The thermophilic ANME-1 do not produce sufficient hydrogen to sustain the observed growth of the HotSeep-1 partner. Enhancing the growth of the HotSeep-1 partner by hydrogen addition represses methane oxidation and the metabolic activity of ANME-1. Further supporting the hypothesis of direct electron transfer between the partners, we observe that under TAOM conditions, both ANME and the HotSeep-1 bacteria overexpress genes for extracellular cytochrome production and form cell-to-cell connections that resemble the nanowire structures responsible for interspecies electron transfer between syntrophic consortia of Geobacter. HotSeep-1 highly expresses genes for pili production only during consortial growth using methane, and the nanowire-like structures are absent in HotSeep-1 cells isolated with hydrogen. These observations suggest that direct electron transfer is a principal mechanism in TAOM, which may also explain the enigmatic functioning and specificity of other methanotrophic ANME-SRB consortia.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wegener, Gunter -- Krukenberg, Viola -- Riedel, Dietmar -- Tegetmeyer, Halina E -- Boetius, Antje -- England -- Nature. 2015 Oct 22;526(7574):587-90. doi: 10.1038/nature15733.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck Institute for Marine Microbiology, 28359 Bremen, Germany. ; MARUM, Center for Marine Environmental Sciences, University Bremen, 28359 Bremen, Germany. ; Max Planck Institute for Biophysical Chemistry, 37077 Gottingen, Germany. ; Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany. ; Center for Biotechnology, Bielefeld University, 33615 Bielefeld, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26490622" target="_blank"〉PubMed〈/a〉
Keywords:
Anaerobiosis
;
Archaea/*metabolism
;
Bacteria/*metabolism
;
Cytochromes/metabolism
;
Electron Transport
;
Fimbriae, Bacterial/metabolism
;
Geologic Sediments/microbiology
;
Heme/metabolism
;
Hydrogen/metabolism
;
Hydrothermal Vents/microbiology
;
Methane/*metabolism
;
Microbiota/physiology
;
Molecular Sequence Data
;
Oceans and Seas
;
Sulfates/metabolism
;
Symbiosis
;
Temperature
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
