title: Diversity and methane oxidation of active epibiotic methanotrophs on live Shinkaia crosnieri.
abstract: Shinkaia crosnieri is a galatheid crab that predominantly dwells in deep-sea hydrothermal systems in the Okinawa Trough, Japan. In this study, the phylogenetic diversity of active methanotrophs in the epibiotic microbial community on the setae of S. crosnieri was characterized by reverse transcription-polymerase chain reaction (RT-PCR) of a functional gene (pmoA) encoding a subunit of particulate methane monooxygenase. Phylogenetic analysis of pmoA transcript sequences revealed that the active epibiotic methanotrophs on S. crosnieri setae consisted of gammaproteobacterial type Ia and Ib methanotrophs. The effect of different RNA stabilization procedures on the abundance of pmoA and 16S rRNA transcripts in the epibiotic community was estimated by quantitative RT-PCR. Our novel RNA fixation method performed immediately after sampling effectively preserved cellular RNA assemblages, particularly labile mRNA populations, including pmoA mRNA. Methane consumption in live S. crosnieri was also estimated by continuous-flow incubation under atmospheric and in situ hydrostatic pressures, and provided a clear evidence of methane oxidation activity of the epibiotic microbial community, which was not significantly affected by hydrostatic pressure. Our study revealed the significant ecological function and nutritional contribution of epibiotic methanotrophs to the predominant S. crosnieri populations in the Okinawa Trough deep-sea hydrothermal systems. In conclusion, our study gave clear facts about diversity and methane oxidation of active methanotrophs in the epibiotic community associated with invertebrates.
authors.affiliation: Subsurface Geobiology Advanced Research (SUGAR) Project, Extremobiosphere Research Program (XBR), Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
authors.forename: Tomo-o
authors.initials: TO
authors.lastname: Watsuji
authors.affiliation: 1] Subsurface Geobiology Advanced Research (SUGAR) Project, Extremobiosphere Research Program (XBR), Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan [2] Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Chemosymbiosis System Genomics Team, XBR, Institute of Biogeosciences, JAMSTEC, Yokosuka, Kanagawa, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takaki
authors.affiliation: Life Science Research Center, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ueda
authors.affiliation: Subsurface Geobiology Advanced Research (SUGAR) Project, Extremobiosphere Research Program (XBR), Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kawagucci
authors.affiliation: Subsurface Geobiology Advanced Research (SUGAR) Project, Extremobiosphere Research Program (XBR), Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
mesh_terms: D000818:Animals; D033381:Anomura / Q000382:microbiology*; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D060086:Hydrothermal Vents / Q000737:chemistry / Q000382:microbiology; D007564:Japan; D008697:Methane / Q000032:analysis; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D010105:Oxygenases; C021555:methane monooxygenase; D008697:Methane