<i>Paludisphaera borealis</i> gen. nov., sp. nov., a hydrolytic planctomycete from northern wetlands, and proposal of <i>Isosphaeraceae</i> fam. nov.

Two isolates of aerobic, budding, pink-pigmented bacteria, designated strains PX4T and PT1, were isolated from a boreal Sphagnum peat 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?:?1?9 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 PX4T and PT1 were members of the order Planctomycetales and displayed 93–94?% 16S rRNA gene sequence similarity to Aquisphaera giovannonii, 91–92?% to species of the genus Singulisphaera and 90–91?% to Isosphaera 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 name Paludisphaera borealis gen. nov., sp. nov., is proposed. The type strain is PX4T (?=?DSM 28747T?=?VKM B-2904T). We also suggest the establishment of a novel family, Isosphaeraceae fam. 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 genera Isosphaera, Aquisphaera, Singulisphaera and Paludisphaer

<i>Telmatocola sphagniphila</i> gen. nov., sp. nov., a Novel Dendriform Planctomycete from Northern Wetlands

Members of the phylum Planctomycetes are common inhabitants of northern wetlands. We used barcoded pyrosequencing to survey bacterial diversity in an acidic (pH 4.0) Sphagnum peat sampled from the peat bog Obukhovskoye, European North Russia. A total of 21189 bacterial 16S rRNA gene sequences were obtained, of which 1081 reads (5.1%) belonged to the Planctomycetes. Two-thirds of these sequences affiliated with planctomycete groups for which characterized representatives have not yet been available. Here, we describe two organisms from one of these previously uncultivated planctomycete groups. One isolate, strain OB3, was obtained from the peat sample used in our molecular study, while another strain, SP2T (=DSM 23888T = VKM B-2710T), was isolated from the peat bog Staroselsky moss. Both isolates are represented by aerobic, budding, pink-pigmented, non-motile, spherical cells that are arranged in unusual, dendriform-like structures during growth on solid media. These bacteria are moderately acidophilic and mesophilic, capable of growth at pH 4.0–7.0 (optimum pH 5.0–5.5) and at 6–30°C (optimum 20–26°C). The preferred growth substrates are various heteropolysaccharides and sugars, the latter being utilized only if provided in low concentrations (=0.025%). In contrast to other described planctomycetes, strains SP2T and OB3 possess weak cellulolytic potential. The major fatty acids are C16:1?5c, C18:1?5c, C16:0, and C18:0. Characteristic lipids are the n-C31 polyunsaturated alkene (9–10 double bonds) and C30:1/C32:1 (?-1) hydroxy fatty acids. The G + C content of the DNA is 58.5–59.0 mol%. Strains SP2T and OB3 share identical 16S rRNA gene sequences, which exhibit only 86 and 87% similarity to those of Gemmata obscuriglobus and Zavarzinella formosa. Based on the characteristics reported here, we propose to classify these novel planctomycetes as representatives of a novel genus and species, Telmatocola sphagniphila gen. nov., sp. no

Methylocystis bryophila sp. nov., a Novel Facultatively Methanotrophic Bacterium from Acidic Sphagnum Peat, and Emended Description of the Genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993

A new species is proposed for two facultatively methanotrophic representatives of the genus Methylocystis, strains H2sT and S284, which were isolated from an acidic (pH 4.3) Sphagnum peat bog lake (Teufelssee, Germany) and an acidic (pH 3.8) peat bog (European North Russia), respectively. Cells of strains H2sT and S284 are aerobic, Gram-negative, non-motile, curved coccoids or short rods that contain an intracytoplasmic membrane system typical of type II methanotrophs. They possess both a soluble and a particulate methane monooxygenase (MMO); the latter is represented by two isozymes, pMMO1 and pMMO2. The preferred growth substrates are methane and methanol. In the absence of C1 substrates, however, these methanotrophs are capable of slow growth on acetate. Atmospheric nitrogen is fixed by means of an aero-tolerant nitrogenase. Strains H2sT and S284 develop between pH 4.2 and 7.6 (optimum pH 6.0-6.5), and at temperatures between 8 and 37°C (optimum 25-30°C). The major fatty acids are C18:1w8c, C18:1w7c, and C16:1w7c; the major quinone is Q-8. The DNA G+C content is 62.0-62.3 mol%. Strains H2sT and S284 share identical 16S rRNA gene sequences, which displayed 96.6-97.3% similarity to sequences of other taxonomically characterized members of the genus Methylocystis. Therefore, strains H2sT and S284 are classified as a novel species, for which the name Methylocystis bryophila sp. nov. is proposed. Strain H2sT (=DSM 21852T = VKM B-2545T) is the type strain of Methylocystis bryophila.

<i>Paludibaculum fermentans</i> gen. nov., sp. nov., a facultative anaerobe capable of dissimilatory iron reduction from subdivision 3 <i>Acidobacteria</i>

A facultatively anaerobic, non-pigmented and non-spore-forming bacterium was isolated from a littoral wetland of a boreal lake located in Valaam Island, Northern Russia, and designated strain P105T. Cells of this isolate are Gram-negative, non-motile rods coated by S-layers with p2 lattice symmetry. Sugars are the preferred growth substrates. Under anoxic conditions, strain P105T is capable of fermentation and dissimilatory Fe(III) reduction. End products of fermentation are acetate, propionate, and H2. Strain P105T is a mildly acidophilic, mesophilic organism, capable of growth at a pH range of 4.0 - 7.2 (optimum pH 5.5-6.0) and at temperatures between 4 and 35 °C (optimum at 20-28 °C). The major fatty acids are iso-C15:0 and C16:1w7c; the cells contain also significant amounts of 13, 16-dimethyl octacosanedioic acid. The major polar lipids are phosphocholine and phosphoethanolamine; the quinone is MK-8. The G+C content of the DNA is 60.5 mol%. 16S rRNA gene sequence analysis showed that strain P105T belongs to subdivision 3 Acidobacteria and is only distantly related (90% sequence similarity) to the only currently characterized member of this subdivision, Bryobacter aggregatus. The novel isolate differs from Bryobacter aggregatus by cell morphology, ability to grow under anoxic conditions, the presence of iron- and nitrate-reducing capabilities, as well as quinone and polar lipid compositions. These differences suggest that strain P105T (=DSM 26340T = VKM B-2878T) represents a novel genus and species, for which the name Paludibaculum fermentans gen. nov., sp. nov., is proposed

Singulisphaera acidiphila gen. nov., sp. nov., a non-filamentous, Isosphaera-like planctomycete from acidic northern wetlands

Four novel strains of budding bacteria, designated MOB10T, PO2, MPL1015 and BG32, were isolated from acidic wetlands of northern Russia. Cells of these four strains were aerobic, non-motile spheres that occurred singly or in shapeless aggregates and attached to surfaces by means of a holdfast material. The isolates were moderately acidophilic, mesophilic organisms capable of growth between pH 4.2 and 7.5 (optimum growth at pH 5.0–6.2) and at temperatures between 4 and 33 °C (optimum growth at 20–26 °C). The strains possessed a complex intracellular membrane system that compartmentalized the cells. The major fatty acids were C16 : 0, C18 : 19c and C18 : 26c,12c. The major quinone was menaquinone-6 (MK-6). The G+C content of the DNA was 57.8–59.9 mol%. 16S rRNA gene sequence analysis showed that strains MOB10T, PO2, MPL1015 and BG32 were members of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Isosphaera, exhibiting 90 % sequence similarity to the type strain of the thermophilic planctomycete Isosphaera pallida and 95–95.5 % sequence similarity to a taxonomically uncharacterized group of filamentous bacteria from activated sludge, ‘Nostocoida limicola’ III. However, compared with ‘Nostocoida limicola’ III and Isosphaera pallida, the new isolates from acidic wetlands were non-filamentous, unpigmented bacteria, which possessed highly distinctive phospholipid fatty acid profiles and were capable of growth and of degrading several biopolymers under acidic, microaerobic and cold conditions. The data suggest that the four isolates should be considered as representing a novel species of a new genus of the order Planctomycetales, for which the name Singulisphaera acidiphila gen. nov., sp. nov. is proposed. The type strain of Singulisphaera acidiphila is MOB10T (=ATCC BAA-1392T =VKM B-2454T =DSM 18658T).

Zavarzinella formosa gen. nov., sp. nov., a novel stalked, Gemmata-like planctomycete from a Siberian peat bog

An aerobic, pink-pigmented, budding and rosette-forming bacterium was isolated from an acidic Sphagnum peat bog and designated strain A10T. The 16S rRNA gene sequence analysis showed that strain A10T was a member of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Gemmata, with 90 % sequence similarity to that of Gemmata obscuriglobus, the only taxonomically described organism of this group. Ellipsoid-shaped cells of strain A10T were uniformly covered with crateriform pits and possessed long (up to 10–15 µm) and unusually thick (0.5–0.7 µm) stalks of a unique ultrastructure. Thin sections revealed a complex intracellular membrane system compartmentalizing the cells. Strain A10T was a moderately acidophilic, mesophilic organism capable of growth at pH values between 3.8 and 7.2 (with an optimum at pH 5.5–6.0) and at temperatures between 10 and 30 °C (with an optimum at 20–25 °C). The major fatty acids were C18 : 0, C18 : 15c and C16 : 15c and the major quinone was MK-6. Cells of strain A10T contained high amounts of bound saturated and monounsaturated C26–C32 (-1) hydroxy fatty acids. The G+C content of the DNA was 62.5 mol%. The unique cell morphology, the capability of growth in acidic conditions and a number of chemotaxonomic and genotypic characteristics served to differentiate strain A10T from G. obscuriglobus. Based on these data, the novel isolate should be considered as representing a novel genus and species of planctomycetes, for which the name Zavarzinella formosa gen. nov., sp. nov. is proposed The type strain is A10T (=DSM 19928T=VKM B-2478T)

<i>Planctomicrobium piriforme</i> gen. nov., sp. nov., a stalked planctomycete from a littoral wetland of a boreal lake

An aerobic, budding, non-pigmented and rosette-forming bacterium was isolated from a littoral wetland of a boreal lake located in Valaam Island, northern Russia, and designated strain P3T.Ellipsoidal to pear-shaped cells of this bacterium were covered with crateriform pits and possessed stalks suggesting a planctomycete morphotype. 16S rRNA gene sequence analysis confirmed that strain P3T was a member of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Planctomyces, with 89 and 86% sequence similarity to Planctomyces brasiliensis and Planctomyces maris, respectively. Strain P3T was a mildly acidophilic, mesophilic organism capable of growth at pH values between pH 4.2 and 7.1 (with an optimum at pH 6.0–6.5) and at temperatures between 10 and 30 o C (optimum at 20–28 o C).Most sugars, a number of polysaccharides and several organic acids were the preferred growthsubstrates. Compared with Planctomyces brasiliensis and Planctomyces maris, which require NaCl for growth, strain P3T was salt-sensitive and did not develop at NaCl concentrations above 0.5% (w/v). The major fatty acids were C16 : 0 and C16 : 1w7c; the cells also contained significant amounts of C18 : 1w7c and C18 : 0. The major intact polar lipids were diacylglycerol-O-(N,N,Ntrimethyl)homoserine (DGTS) lipids; the major neutral lipids were long-chain 1,(w-1)-diols andC31 : 9 hydrocarbon. The quinone was MK-6, and the G+C content of the DNA was 59.0 mol%.Strain P3T differed from Planctomyces brasiliensis and Planctomyces maris by cell morphology,substrate utilization pattern and a number of physiological characteristics. Based on these data,the novel isolate should be considered as representing a novel genus and species ofplanctomycetes, for which the name Planctomicrobium piriforme gen. nov., sp. nov., is proposed. The type strain is P3T (=DSM 26348T=VKM B-2887T)

<i>Fimbriiglobus ruber</i> gen. nov., sp. nov., a <i>Gemmata</i>-like planctomycete from <i>Sphagnum</i> peat bog and the proposal of <i>Gemmataceae</i> fam. nov.

An aerobic, budding, dark pink to red-pigmented bacterium was isolated from an acidic boreal Sphagnum peat bog anddesignated strain SP5T. Cells of this strain were non-motile spheres that were uniformly covered with crateriform pits andfimbria, and tended to form aggregates during growth in liquid media. Strain SP5T was capable of growth between pH 4.0and pH 6.8 (optimum at pH 5.5–6.0) and at temperatures between 10 and 30 ?C (optimum at 20–25 ?C). The preferred growthsubstrates were sugars and some heteropolysaccharides. The major fatty acids were C20 : 1!9c, C16 : 1!9c and C16 : 0, and themajor polar lipid was trimethylornithine. Cells contained also significant amounts of bound (!-1)OH-C30 : 1 fatty acid. Thequinone was menaquinone-6, and the G+C content of the DNA was 60.7 mol%. Strain SP5T was a member of the orderPlanctomycetales and belonged to the phylogenetic lineage defined by the genus Gemmata. It displayed 88 and 89% 16SrRNA gene sequence similarity to Gemmata obscuriglobusUQM 2246T and ‘Gemmata massiliana’ IIL30, 89% to Zavarzinellaformosa A10T and 86% to Telmatocola sphagniphila SP2T. However, strain SP5T differed from members of these genera bycell morphology, substrate utilization pattern and fatty acid composition. Based on these data, the novel isolate should beconsidered as representing a novel species of a new genus of planctomycetes, for which the name Fimbriiglobus ruber gen.nov., sp. nov, is proposed. The type strain is SP5T (=LMG 29572T=VKM B-3045T). We also suggest the establishment of anovel family, Gemmataceaefam. nov., which includes the phylogenetically related genera Gemmata, Zavarzinella, Telmatocolaand Fimbriiglobus

Zavarzinella formosa gen. nov., sp. nov., a novel stalked, Gemmata-like planctomycete from a Siberian peat bog

An aerobic, pink-pigmented, budding and rosette-forming bacterium was isolated from an acidic Sphagnum peat bog and designated strain A10T. The 16S rRNA gene sequence analysis showed that strain A10T was a member of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Gemmata, with 90 % sequence similarity to that of Gemmata obscuriglobus, the only taxonomically described organism of this group. Ellipsoid-shaped cells of strain A10T were uniformly covered with crateriform pits and possessed long (up to 10–15 µm) and unusually thick (0.5–0.7 µm) stalks of a unique ultrastructure. Thin sections revealed a complex intracellular membrane system compartmentalizing the cells. Strain A10T was a moderately acidophilic, mesophilic organism capable of growth at pH values between 3.8 and 7.2 (with an optimum at pH 5.5–6.0) and at temperatures between 10 and 30 °C (with an optimum at 20–25 °C). The major fatty acids were C18 : 0, C18 : 15c and C16 : 15c and the major quinone was MK-6. Cells of strain A10T contained high amounts of bound saturated and monounsaturated C26–C32 (-1) hydroxy fatty acids. The G+C content of the DNA was 62.5 mol%. The unique cell morphology, the capability of growth in acidic conditions and a number of chemotaxonomic and genotypic characteristics served to differentiate strain A10T from G. obscuriglobus. Based on these data, the novel isolate should be considered as representing a novel genus and species of planctomycetes, for which the name Zavarzinella formosa gen. nov., sp. nov. is proposed The type strain is A10T (=DSM 19928T=VKM B-2478T).