title: Mariprofundus micogutta sp. nov., a novel iron-oxidizing zetaproteobacterium isolated from a deep-sea hydrothermal field at the Bayonnaise knoll of the Izu-Ogasawara arc, and a description of Mariprofundales ord. nov. and Zetaproteobacteria classis nov.
abstract: A novel iron-oxidizing chemolithoautotrophic bacterium, strain ET2T, was isolated from a deep-sea sediment in a hydrothermal field of the Bayonnaise knoll of the Izu-Ogasawara arc. Cells were bean-shaped, curved short rods. Growth was observed at a temperature range of 15-30 °C (optimum 25 °C, doubling time 24 h) and a pH range of 5.8-7.0 (optimum pH 6.4) in the presence of NaCl at a range of 1.0-4.0 % (optimum 2.75 %). The isolate was a microaerophilic, strict chemolithoautotroph capable of growing using ferrous iron and molecular oxygen (O2) as the sole electron donor and acceptor, respectively; carbon dioxide as the sole carbon source; and either ammonium or nitrate as the sole nitrogen source. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the new isolate was related to the only previously isolated Mariprofundus species, M. ferrooxydans. Although relatively high 16S rRNA gene similarity (95 %) was found between the new isolate and M. ferrooxydans, the isolate was distinct in terms of cellular fatty acid composition, genomic DNA G+C content and cell morphology. Furthermore, genomic comparison between ET2Tand M. ferrooxydans PV-1 indicated that the genomic dissimilarity of these strains met the standard for species-level differentiation. On the basis of its physiological and molecular characteristics, strain ET2T(= KCTC 15556T= JCM 30585T) represents a novel species of Mariprofundus, for which the name Mariprofundus micogutta is proposed. We also propose the subordinate taxa Mariprofundales ord. nov. and Zetaproteobacteria classis nov. in the phylum Proteobacteria.
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan. makita@jamstec.go.jp.|Department of Applied Chemistry, Kanagawa Institute of Technology, 1030 Shimo-ogino, Atsugi, Kanagawa, 243-0292, Japan. makita@jamstec.go.jp.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Makita
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.|Department of Applied Chemistry, Kanagawa Institute of Technology, 1030 Shimo-ogino, Atsugi, Kanagawa, 243-0292, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Tanaka
authors.affiliation: Department of Environmental Conservation, Graduate School of Agriculture, Ehime University, Tarumi, Matsuyama, 790-8566, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mitsunobu
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyazaki
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Nunoura
authors.affiliation: Section 1 Geochemical Oceanography, Office of Marine Research Department of Marine Science, Marine Works Japan Ltd., Yokosuka, 237-0061, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Uematsu
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takaki
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Shinro
authors.initials: S
authors.lastname: Nishi
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shimamura
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
mesh_terms: D052837:Chemoautotrophic Growth; D005227:Fatty Acids / Q000032:analysis; D060086:Hydrothermal Vents; D007501:Iron / Q000378:metabolism; D010802:Phylogeny; D020560:Proteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*
chemical_list: D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D007501:Iron
keywords: Bayonnaise knoll; Hydrothermal field; Iron-oxidizing bacteria; Mariprofundus sp.; Zetaproteobacteria