title: Methyloferula stellata gen. nov., sp. nov., an acidophilic, obligately methanotrophic bacterium that possesses only a soluble methane monooxygenase.
abstract: Two strains of aerobic methanotrophic bacteria, AR4(T) and SOP9, were isolated from acidic (pH 3.8-4.0) Sphagnum peat bogs in Russia. Another phenotypically similar isolate, strain LAY, was obtained from an acidic (pH 4.0) forest soil in Germany. Cells of these strains were Gram-negative, non-pigmented, non-motile, thin rods that multiplied by irregular cell division and formed rosettes or amorphous cell conglomerates. Similar to Methylocella species, strains AR4(T), SOP9 and LAY possessed only a soluble form of methane monooxygenase (sMMO) and lacked intracytoplasmic membranes. Growth occurred only on methane and methanol; the latter was the preferred growth substrate. mRNA transcripts of sMMO were detectable in cells when either methane or both methane and methanol were available. Carbon was assimilated via the serine and ribulose-bisphosphate (RuBP) pathways; nitrogen was fixed via an oxygen-sensitive nitrogenase. Strains AR4(T), SOP9 and LAY were moderately acidophilic, mesophilic organisms capable of growth between pH 3.5 and 7.2 (optimum pH 4.8-5.2) and at 4-33 °C (optimum 20-23 °C). The major cellular fatty acid was 18 : 1ω7c and the quinone was Q-10. The DNA G+C content was 55.6-57.5 mol%. The isolates belonged to the family Beijerinckiaceae of the class Alphaproteobacteria and were most closely related to the sMMO-possessing methanotrophs of the genus Methylocella (96.4-97.0 % 16S rRNA gene sequence similarity), particulate MMO (pMMO)-possessing methanotrophs of the genus Methylocapsa (96.1-97.0 %), facultative methylotrophs of the genus Methylovirgula (96.1-96.3 %) and non-methanotrophic organotrophs of the genus Beijerinckia (96.5-97.0 %). Phenotypically, strains AR4(T), SOP9 and LAY were most similar to Methylocella species, but differed from members of this genus by cell morphology, greater tolerance of low pH, detectable activities of RuBP pathway enzymes and inability to grow on multicarbon compounds. Therefore, we propose a novel genus and species, Methyloferula stellata gen. nov., sp. nov., to accommodate strains AR4(T), SOP9 and LAY. Strain AR4(T) ( = DSM 22108(T)  = LMG 25277(T)  = VKM B-2543(T)) is the type strain of Methyloferula stellata.
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Vorobev
authors.affiliation: Max-Planck-Institut für terrestrische Mikrobiologie, D-35043 Marburg, Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Baani
authors.affiliation: G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow region 142292, Russia.
authors.forename: Nina V
authors.initials: NV
authors.lastname: Doronina
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Allyson L
authors.initials: AL
authors.lastname: Brady
authors.affiliation: Max-Planck-Institut für terrestrische Mikrobiologie, D-35043 Marburg, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Liesack
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.|Max-Planck-Institut für terrestrische Mikrobiologie, D-35043 Marburg, Germany.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Dunfield
authors.affiliation: S. N. Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow 117312, Russia.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dedysh
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001482:Base Composition; D042062:Beijerinckiaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D002244:Carbon / Q000378:metabolism; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D005227:Fatty Acids / Q000032:analysis; D020869:Gene Expression Profiling; D005858:Germany; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D010105:Oxygenases / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D002244:Carbon; D010105:Oxygenases; C021555:methane monooxygenase; D008697:Methane; D000432:Methanol