title: Methylovulum psychrotolerans sp. nov., a cold-adapted methanotroph from low-temperature terrestrial environments, and emended description of the genus Methylovulum.
abstract: Two isolates of aerobic methanotrophic bacteria, strains Sph1T and Sph2, were obtained from cold methane seeps in a floodplain of the river Mukhrinskaya, Irtysh basin, West Siberia. Another morphologically and phenotypically similar methanotroph, strain OZ2, was isolated from a sediment of a subarctic freshwater lake, Archangelsk region, northern Russia. Cells of these three strains were Gram-stain-negative, light-pink-pigmented, non-motile, encapsulated, large cocci that contained an intracytoplasmic membrane system typical of type I methanotrophs. They possessed a particulate methane monooxygenase enzyme and utilized only methane and methanol. Strains Sph1T, Sph2 and OZ2 were able to grow at a pH range of 4.0-8.9 (optimum at pH 6.0-7.0) and at temperatures between 2 and 36 °C. Although their temperature optimum was at 20-25 °C, these methanotrophs grew well at lower temperatures, down to 4 °C. The major cellular fatty acids were C16 : 1ω5c, C16 : 1ω6c, C16 : 1ω7c, C16 : 1ω8c, C16 : 0 and C14 : 0; the DNA G+C content was 51.4-51.9 mol%. Strains Sph1T, Sph2 and OZ2 displayed nearly identical (99.1-99.7 % similarity) 16S rRNA gene sequences and belonged to the family Methylococcaceae of the class Gammaproteobacteria. The most closely related organism was Methylovulum miyakonense HT12T (96.0-96.5 % 16S rRNA gene sequence similarity and 90 % pmoA sequence similarity). The novel isolates, however, differed from Methylovulum miyakonense HT12T by cell morphology, pigmentation, absence of soluble methane monooxygenase, more active growth at low temperatures, growth over a broader pH range and higher DNA G+C content. On the basis of these differences, we propose a novel species, Methylovulum psychrotolerans sp. nov., to accommodate these methanotrophs. Strain Sph1T (=LMG 29227T=VKM B-3018T) is the type strain.
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Igor Y
authors.initials: IY
authors.lastname: Oshkin
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Svetlana E
authors.initials: SE
authors.lastname: Belova
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Danilova
authors.affiliation: M.V. Lomonosov Moscow State University, Moscow 119991, Russia.
authors.forename: Kirill K
authors.initials: KK
authors.lastname: Miroshnikov
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, PO Box 59, 1790 AB Den Burg, The Netherlands.
authors.forename: W Irene C
authors.initials: WIC
authors.lastname: Rijpstra
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, PO Box 59, 1790 AB Den Burg, The Netherlands.|Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Geochemistry, Utrecht, The Netherlands.
authors.forename: Jaap S
authors.initials: JS
authors.lastname: Sinninghe Damsté
authors.affiliation: Max-Planck-Institut für terrestrische Mikrobiologie, D-35043 Marburg, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Liesack
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dedysh
mesh_terms: D015373:Bacterial Typing Techniques; D001482:Base Composition; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry; D019015:Geologic Sediments / Q000382:microbiology*; D060106:Lakes / Q000382:microbiology*; D008697:Methane / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D008772:Methylococcaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D010105:Oxygenases / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D017422:Sequence Analysis, DNA; D012800:Siberia
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D010105:Oxygenases; C021555:methane monooxygenase; D008697:Methane; D000432:Methanol