title: Distribution of anaerobic carbon monoxide dehydrogenase genes in deep subseafloor sediments.
abstract: Carbon monoxide (CO) is the simplest oxocarbon generated by the decomposition of organic compounds, and it is expected to be in marine sediments in substantial amounts. However, the availability of CO in the deep subseafloor sedimentary biosphere is largely unknown even though anaerobic oxidation of CO is a thermodynamically favourable reaction that possibly occurs with sulphate reduction, methanogenesis, acetogenesis and hydrogenesis. In this study, we surveyed for the first time the distribution of the CO dehydrogenase gene (cooS), which encodes the catalytic beta subunit of anaerobic CO dehydrogenase (CODH), in subseafloor sediment-core samples from the eastern flank of the Juan de Fuca Ridge, Mars-Ursa Basin, Kumano Basin, and off the Shimokita Peninsula, Japan, during Integrated Ocean Drilling Program (IODP) Expeditions 301, 308 and 315 and the D/V Chikyu shakedown cruise CK06-06, respectively. Our results show the occurrence of diverse cooS genes from the seafloor down to about 390 m below the seafloor, suggesting that microbial communities have metabolic functions to utilize CO in anoxic microbial ecosystems beneath the ocean floor, and that the microbial community potentially responsible for anaerobic CO oxidation differs in accordance with possible energy-yielding metabolic reactions in the deep subseafloor sedimentary biosphere.
  
  
  CONCLUSIONS
  Little is known about the microbial community associated with carbon monoxide (CO) in the deep subseafloor. This study is the first survey of a functional gene encoding anaerobic carbon monoxide dehydrogenase (CODH). The widespread occurrence of previously undiscovered CO dehydrogenase genes (cooS) suggests that diverse micro-organisms are capable of anaerobic oxidation of CO in the deep subseafloor sedimentary biosphere.
authors.affiliation: Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Nankoku, Kochi, Japan.|Geobiotechnology Group, Research and Development Center for Submarine Resources, JAMSTEC, Nankoku, Kochi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hoshino
authors.affiliation: Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Nankoku, Kochi, Japan.|Geobiotechnology Group, Research and Development Center for Submarine Resources, JAMSTEC, Nankoku, Kochi, Japan.|Research and Development Center for Ocean Drilling Science, JAMSTEC, Yokohama, Kanagawa, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Inagaki
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D001421:Bacteria, Anaerobic / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002248:Carbon Monoxide / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D007564:Japan; D009097:Multienzyme Complexes / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D009097:Multienzyme Complexes; D002248:Carbon Monoxide; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase
keywords: carbon monoxide dehydrogenase; cooS gene; deep biosphere; functional gene; subseafloor sediment