title: Paludisphaera borealisgen. nov., sp. nov., a hydrolytic planctomycete from northern wetlands, and proposal ofIsosphaeraceaefam. nov.
abstract: Two isolates of aerobic, budding, pink-pigmented bacteria, designated strains PX4Tand PT1, were isolated from a borealSphagnumpeat bog and a forested tundra wetland. Cells of these strains were non-motile spheres that occurred singly or in short chains. Novel isolates were capable of growth at pH values between 3.5 and 6.5 (optimum at pH 5.0-5.5) and at temperatures between 6 and 30 °C (optimum at 15-25 °C). Most sugars and a number of polysaccharides including pectin, xylan, lichenin and Phytagel were used as growth substrates. The major fatty acids were C16 : 0, C18 : 1ω9 and C18 : 0; the major polar lipids were phosphocholine and trimethylornithine. The quinone was menaquinone-6, and the G+C content of the DNA was 66 mol%. Strains PX4Tand PT1 were members of the orderPlanctomycetalesand displayed 93-94 % 16S rRNA gene sequence similarity toAquisphaera giovannonii, 91-92 % to species of the genusSingulisphaeraand 90-91 % toIsosphaera pallida. The two novel strains, however, differed from members of these genera by cell morphology, substrate utilization pattern and a number of physiological characteristics. Based on these data, the novel isolates should be considered as representing a novel genus and species of planctomycetes, for which the namePaludisphaera borealisgen. nov., sp. nov., is proposed. The type strain is PX4T( = DSM 28747T= VKM B-2904T). We also suggest the establishment of a novel family,Isosphaeraceaefam. nov., to accommodate stalk-free planctomycetes with spherical cells, which can be assembled in short chains, long filaments or shapeless aggregates. This family includes the generaIsosphaera, Aquisphaera, SingulisphaeraandPaludisphaera.
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Irina S
authors.initials: IS
authors.lastname: Kulichevskaya
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
authors.forename: Anastasia A
authors.initials: AA
authors.lastname: Ivanova
authors.affiliation: G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow region, 142292, Russia.
authors.forename: Natalia E
authors.initials: NE
authors.lastname: Suzina
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: 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