Two novel strains of bacteria, CA1-15T and BIUV-7T, were isolated from soil samples gathered in Cheonan-si, Republic of Korea, and Inje-gun, Republic of Korea, respectively. These bacteria are Gram-negative, aerobic, and non-motile. Phylogenetic evaluations, using the sequence of the 16S rRNA gene, showed that strains CA1-15T and BIUV-7T belong to a distinctive clade within the family Sphingomonadaceae (order Sphingomonadales, class Alphaproteobacteria). The strains exhibited the highest similarity in their genetic makeup with representatives of the genus Sphingomonas. Strain CA1-15T was closely related to Sphingomonas echinoides NRRL B-3126T (97.8% similarity in 16S rRNA gene sequence), Sphingomonas oligophenolica JCM 12,082T (97.8%), Sphingomonas glacialis C16yT (97.6%) and Sphingomonas psychrolutea MDB1-AT (97.3%). Strain BIUV-7T was closely related to Sphingomonas nostoxanthinifaciens AK-PDB1-5T (97.0%), Sphingomonas vulcanisoli SN6-13T (96.3%), Sphingomonas naphthae DKC-5-1T (96.2%), and Sphingomonas prati W18RDT (95.7%). The optimal growth conditions for strains CA1-15T and BIUV-7T were determined to be at pH 7.0 and a temperature of 25°C. Analysis of the cellular fatty acids of strain CA1-15T and BIUV-7T revealed that summed feature 8 (C18:1ω7c/C18:1ω6c) (60.4%), summed feature 8 (C18:1ω7c/C18:1ω6c) (62.9%) were the major component, respectively. Additionally, both strains exhibited ubiquinone Q-10 as their major respiratory quinone, and diphosphatidylglycerol (DPG), glycosphingolipid (SGL), and phosphatidylethanolamine (PE) as the major polar lipid. The genome of strain CA1-15T measures 4,133,944bp, comprising 4,026 coding sequences (CDSs) and 46 tRNA genes. Similarly, the genome of strain BIUV-7T is 4,563,252bp, characterized by 4,226 CDSs and 44 tRNA genes. The average nucleotide identity (ANI) analysis and digital DNA-DNA hybridization (dDDH) values between strain CA1-15T and other Sphingomonas species range from 73.2 to 79.9% and 19.4-22.9%, respectively. Comparatively, ANI and dDDH values between strain BIUV-7T and other Sphingomonas species are in the range of 72.9-76.5% and 19.3-20.9%, respectively. Based on the biochemical, chemotaxonomic, and phylogenetic analyses, it is evident that strains CA1-15T and BIUV-7T represent two novel bacterial species within the genus Sphingomonas. Accordingly, the names Sphingomonas immobilis sp. nov. and Sphingomonas natans sp. nov. are proposed. also, CA1-15T(= KCTC 92960T = NBRC 116547T) is the type strain of Sphingomonas immobilis and BIUV-7T(= KCTC 92961T = NBRC 116546T) is the type strain of Sphingomonas natans.

Lake Vostok is the deepest lake of Antarctica but has poor accessibility for study due to a thick glacial cover, however, water samples of this lake have become available for study just recently. Previously, only the microbiome of the ice cover samples was characterized. Here we report results of bacteriological seeding with subsequent identification of the heterotrophic microorganisms (bacteria and micellar fungi) present by 16S rDNA sequencing as well as results of a direct molecular study of the water microbiome. Surprisingly, the data obtained gave evidence of a predominant occurrence of common chemoorganotrophs that were rather psychrotolerant than psychrophilic. We isolated and described strains belonging to eight heterotrophic microbial species able to grow in a rich medium: six bacterial strains belonging to the species Microbacterium testaceum and Microbacterium trichothecenolyticum, Brevundimonas diminuta, Sphingomonas oligophenolica, Sphingomonas sp. and Sphingobium limneticum; and two fungal strains belonging to Dendryphion sp. and Cladosporium fusiforme. Direct study of 16S rDNA purified water samples confirmed the predominance of the Brevundimonas, Microbacterium, Bradyrhizobium, and Bacillus (Bacillus cereus) genera.

Occurrences of 2-methylisoborneol and geosmin –degrading bacteria in a eutrophic reservoir and the role of cell-bound versus dissolved fractions

Ixodes ricinus (I.ricinus) and Dermacentor reticulatus (D.reticulatus) are the most common ticks in Poland. These ticks contain many bacteria, which compose a microbiome with potential impact on humans. The aim of the study was to discover the microbiome of ticks in Poland. Ticks were collected in The Protected Landscape Area of the Bug and Nurzec Valley, Poland, in 2016-2018 by flagging. They were cleaned in 70% ethanol and damaged in mortar with PBS (without Ca2+ and Mg2+ ions). DNA was extracted from the homogenates with spin columns kits, and used as a matrix in end-point PCR for bacterial 16S rRNA fragments amplifications, and further for next generation sequencing (NGS) by ILLUMINA. In 22 ticks (3 I. ricinus and 19 D. reticulatus) 38 microorganisms were detected. The most common were Francisella hispaniensis and Francisella novicida. In 17 ticks, Sphingomonas oligophenolica, and in 12 Rickettsia aeshlimanii were found. In 2, I. ricinus specific DNA of Borrelia americana and Borrelia carolinensis were found. In one female, D. reticulatus Anaplasma phagocytophilum and Anaplasma centrale were found. Pseudomonas lutea and Ps. moraviensis were detected in 9 and 8 ticks, respectively. Polish ticks microbiome contains not only well-known tick-borne pathogens, but also other pathogenic microorganisms. For the first time in Poland, Borrelia americana and Borrelia carolinensis in I. ricinus collected from the environment were detected. The dominant pathogenic microorganisms for humans were Francisella spp. and Rickettsia spp., and non-pathogenic - Sphingomonas oligophenolica. Knowledge of a tick microbiome might be useful in tick-borne biocontrol and tick-borne diseases prevention.

Strain YZ-8T, isolated from soil sampled at Fildes Peninsula, Antarctica, was found to be a Gram-stain-negative, yellow-pigmented, oxidase- and catalase-positive, non-motile, non-spore-forming, rod-shaped and aerobic bacterium. Strain YZ-8T grewoptimally at pH 7.0 and 20 °C. Tolerance to NaCl was up to 0.3 % (w/v) with optimum growth in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YZ-8T belonged to the family Sphingomonas. Strain YZ-8T showed the highest sequence similarities to Sphingomonas molluscorum KMM 3882T (94.4 %), Sphingomonas oligophenolica JCM 12082T (94.4 %), Sphingomonas gotjawalisoli SN6-9T (94.3 %) and Sphingomonas aquatica W1-2-1T (94.3 %). The predominant respiratory isoprenoid quinone and polyamine components were identified as ubiquinone Q-10 and sym-homospermidine, respectively. In addition, carotenoid were also found. The polar lipid profile of the strain YZ-8T was found to contain one phosphatidylethanolamine, an unidentified phospholipid, one diphosphatidylglycerol, one phosphatidylglycerol, two sphingophosphonolipids, one phosphatidylcholine and two unidentified alkali-stable lipids. The G+C content of the genomic DNA was determined to be 58.8 mol%. The main fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c; 35.4 %), summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c; 32.6 %) and C14 : 0 2-OH (7.7 %). On the basis of the evidence presented in this study, a novel species of the genus Sphingomonas, Sphingomonaspaeninsulae sp. nov., is proposed, with the type strain YZ-8T (=CCTCC AB 2017137T=LMG 31027T).

A Gram-stain-negative, rod-shaped bacterium, designated as strain GL-C-18T, was isolated from soil sample collected at Mu Us Sandy Land, China, and its taxonomic position was investigated using a polyphasic approach. Growth was observed in the presence of 0-1 % (w/v) NaCl (optimum, 0 %), pH 6.0-9.0 (optimum, pH 7.0-8.0) and 20-37 °C. On the basis of 16S rRNA gene sequence similarity, strain GL-C-18T belonged to the family Sphingomonadaceae and was most closely related to Sphingosinicella vermicomposti YC7378T (95.7 %), Sphingomonas oligophenolica S213T (95.0 %) and Sphingobium boeckii 301T (94.8 %). The draft genome of strain GL-C-18T was 6.09 Mb, and the G+C content was 66.0 %. The average nucleotide identity value to Sphingosinicella vermicomposti YC7378T was 83.7 %. The predominant respiratory quinone was Q-10. The major fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16:0 and C14 : 0 2OH. The main polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. On the basis of chemotaxonomic, phylogenetic and phenotypic evidence, strain GL-C-18T represents a novel species of the genus Sphingomonas, for which the name Sphingomonasdeserti sp. nov. is proposed. The type strain is GL-C-18T (=ACCC 60076T=KCTC 62411T).

A yellow-pigmented, Gram-stain-negative, short-rod-shaped bacterial strain, MIMD3T, was isolated from biological soil crusts collected in Liangcheng, north-western China. Cell growth could be observed at 10-37 °C (optimum 25 °C), at pH 5-8 (optimum 6.6) and in the presence of 1 % (w/v) NaCl (optimum 0 %). The genomic DNA G+C content was 65.0 mol%. Analysis of 16S rRNA gene sequences showed that strain MIMD3T shared the highest similarity with Sphingomonas vulcanisoli KCTC 42454T (95.1 %), Sphingomonas oligophenolica JCM 12082T (94.8 %), Sphingomonas mali IFO 15500T (94.5 %), Sphingomonas. leidyi ATCC 15260T (94.4 %) and Sphingomonas formosensis CC-Nfb-2T (94.3 %). The strain had Q-10 as the predominant respiratory quinone, and sym-homospermidine as the major polyamine. The major fatty acids of the strain were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C19 : 0 cyclo ω8c, C14 : 0 2-OH and C16 : 0. The main polar lipids of strain MIMD3T were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and sphingoglycolipid. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, it is concluded that strain MIMD3T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas crusticola sp. nov. is proposed. The type strain is MIMD3T (=KCTC 42801T=MCCC 1K01310T).

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, designated W1-2-1T, was isolated from tap water in South Korea. The strain was characterized by a polyphasic approach to clarify its taxonomic position. Strain W1-2-1T grew at 18-42 °C and at pH 6.0-10.0 on R2A medium. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Sphingomonas and is most closely related to the Sphingomonas oligophenolica JCM 12082T (97.2 % similarity), Sphingomonas asaccharolyticaNBRC 15499T (96.8 %), Sphingomonas desiccabilis CP1DT (96.8 %), Sphingomonas pruniNBRC 15498T (96.8 %), Sphingomonas hankookensis ODN7T (96.4 %) and Sphingomonas yabuuchiae DSM 14562T (95.8 %). Chemotaxonomic data [major ubiquinone - Q10, major polyamine - homospermidine, major fatty acids - summed feature 8 (C18 : 1ω7c/ω6c), C16 : 0 and C14 : 0 2-OH and presence of sphingoglycolipid] supported the affiliation of the strain to the genus Sphingomonas. The G+C content of genomic DNA was 67.1 mol%. However, low level of DNA-DNA relatedness value between strain W1-2-1T and S. oligophenolica JCM 12082T and the results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain W1-2-1T from other Sphingomonas species with validly published names. Therefore, the isolate represents a novel species, for which the name Sphingomonas aquatica sp. nov. (type strain W1-2-1T=KACC 18309T=LMG 28596T) is proposed.

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, designated X1(T), was isolated from the permafrost region of Qilian Mountains in northwest of China. Phylogenetic analyses of 16S rRNA gene sequence revealed that strain X1(T) was a member of the genus Sphingomonas and shared the highest 16S rRNA gene sequence similarity with Sphingomonas oligophenolica JCM 12082(T) (96.9%), followed by Sphingomonas glacialis CGMCC 1.8957(T) (96.7%) and Sphingomonas alpina DSM 22537(T) (96.4%). Strain X1(T) was able to grow at 15-30 °C, pH 6.0-10.0 and with 0-0.3% NaCl (w/v). The DNA G+C content of the isolate was 64.8 mol%. Strain X1(T)-contained Q-10 as the dominant ubiquinone and C(18:1)ω7c, C(16:1)ω7c, C(16:0) and C(14:0) 2-OH as the dominant fatty acids. The polar lipid profile of strain XI(T)-contained sphingoglycolipid, phosphatidylglycerol, phosphatidylethanolamine, one unidentified glycolipid and two unidentified phospholipid. Due to the phenotypic and genetic distinctiveness and other characteristic studied in this article, we consider X1(T) as a novel species of the genus Sphingomonas and propose to name it Sphingomonas qilianensis sp. nov. The type strain is X1(T) (=CGMCC 1.15349(T) = KCTC 42862(T)).

A non-motile, rod-shaped, yellow bacterium, designated C16y(T), was isolated from alpine glacier cryoconite. Cells behaved Gram-positively, were aerobic and psychrophilic (good growth at 1-25 °C). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain C16y(T) was related to the genus Sphingomonas and had highest 16S rRNA gene sequence similarity with Sphingomonas oligophenolica JCM 12082(T) (97.6 %) and Sphingomonas echinoides DSM 1805(T) (97.2 %). DNA-DNA hybridization demonstrated that strain C16y(T) could not be considered as a member of either Sphingomonas oligophenolica or Sphingomonas echinoides. Strain C16y(T) contained Q-10 as the predominant ubiquinone and C₁₈:₁ and C₁₆:₀ were the dominant fatty acids. The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, five unidentified glycolipids, two unidentified aminophospholipids and two unidentified lipids. The major polyamines were the triamines sym-homospermidine and spermidine. The G+C content was 67.9 mol%. Combined data from phenotypic, phylogenetic and DNA-DNA relatedness studies demonstrated that strain C16y(T) is a representative of a novel species of the genus Sphingomonas, for which we propose the name Sphingomonas glacialis sp. nov. The type strain is C16y(T) (=DSM 22294(T) =CGMCC 1.8957(T) =CIP 110131(T) [corrected]).

The taxonomic position of a halo- and organo-sensitive, oligotrophic soil bacterium, strain S213(T), was investigated. Cells were Gram-negative, non-motile, strictly aerobic, yellow-pigmented rods of short to medium length on diluted nutrient broth. When 0.1-0.4 % (w/v) NaCl was added to diluted media composed of peptone and meat extract, growth was inhibited with increasing NaCl concentration and the cells became long aberrant forms. When 6 mM CaCl(2) was added, the cells grew quite normally and aberrant cells were no longer found at 0.1-0.5 % (w/v) NaCl. Chemotaxonomically, strain S213(T) contains chemical markers that indicate its assignment to the Sphingomonadaceae: the presence of ubiquinone Q-10 as the predominant respiratory quinone, C(18 : 1) and C(16 : 0) as major fatty acids, C(14 : 0) 2-OH as the major 2-hydroxy fatty acid and sphingoglycolipids. 16S rRNA gene sequence analysis indicated that strain S213(T) belongs to the genus Sphingomonas, exhibiting high sequence similarity to the 16S rRNA gene sequences of Sphingomonas mali IFO 15500(T) (98.3 %), Sphingomonas pruni IFO 15498(T) (98.0 %), Sphingomonas asaccharolytica IFO 15499(T) (97.9 %) and Sphingomonas echinoides DSM 1805(T) (97.8 %). The results of DNA-DNA hybridization experiments and its phenotypic characteristics clearly distinguished the strain from its nearest neighbours and demonstrate that strain S213(T) represents a novel Sphingomonas species, for which the name Sphingomonas oligophenolica sp. nov. is proposed. The type strain is S213(T) (=JCM 12082(T)=CIP 107926(T)).