title: A new cell morphotype among methane oxidizers: a spiral-shaped obligately microaerophilic methanotroph from northern low-oxygen environments.
abstract: Although representatives with spiral-shaped cells are described for many functional groups of bacteria, this cell morphotype has never been observed among methanotrophs. Here, we show that spiral-shaped methanotrophic bacteria do exist in nature but elude isolation by conventional approaches due to the preference for growth under micro-oxic conditions. The helical cell shape may enable rapid motility of these bacteria in water-saturated, heterogeneous environments with high microbial biofilm content, therefore offering an advantage of fast cell positioning under desired high methane/low oxygen conditions. The pmoA genes encoding a subunit of particulate methane monooxygenase from these methanotrophs form a new genus-level lineage within the family Methylococcaceae, type Ib methanotrophs. Application of a pmoA-based microarray detected these bacteria in a variety of high-latitude freshwater environments including wetlands and lake sediments. As revealed by the environmental pmoA distribution analysis, type Ib methanotrophs tend to live very near the methane source, where oxygen is scarce. The former perception of type Ib methanotrophs as being typical for thermal habitats appears to be incorrect because only a minor proportion of pmoA sequences from these bacteria originated from environments with elevated temperatures.
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Danilova
authors.affiliation: G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
authors.forename: Natalia E
authors.initials: NE
authors.lastname: Suzina
authors.affiliation: CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia.
authors.forename: Jodie
authors.initials: J
authors.lastname: Van De Kamp
authors.affiliation: UiT The Arctic University of Norway, Department of Arctic and Marine Biology, Tromsø, Norway.
authors.forename: Mette M
authors.initials: MM
authors.lastname: Svenning
authors.affiliation: CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia.
authors.forename: Levente
authors.initials: L
authors.lastname: Bodrossy
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia.
authors.forename: Svetlana N
authors.initials: SN
authors.lastname: Dedysh
mesh_terms: D017753:Ecosystem; D060106:Lakes / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D008772:Methylococcaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D010105:Oxygenases; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D053833:Wetlands
chemical_list: D010105:Oxygenases; C021555:methane monooxygenase; D008697:Methane; D010100:Oxygen