Myung-Suk Kang

Sphingosinicella ginsenosidimutans sp. nov., with ginsenoside converting activity

The Gram-reaction-negative, strictly aerobic, non-motile, nonspore-forming, and rod-shaped bacterial strain designated BS11T was isolated from the compost and its taxonomic position was investigated by using a polyphasic approach. Strain BS11T grew optimally at 30–37°C and at pH 7.0 in the absence of NaCl on nutrient agar. Strain BS11T displayed β-glucosidase activity that was responsible for its ability to transform ginsenoside Rb1 (one of the dominant active components of ginseng) to Rd. On the basis of 16S rRNA gene sequence similarity, strain BS11T was shown to belong to the family Sphingomonadaceae and was related to Sphingosinicella vermicomposti YC7378T (96.3% sequence similarity), S. xenopeptidilytica 3–2W4T (96.2%), S. microcystinivorans Y2T (96.1%), and S. soli KSL-125T (95.9%). The G+C content of the genomic DNA was 64.9%. The major menaquinone was Q-10 and the major fatty acids were summed feature 7 (comprising C18:1ω7c/ω9t/ω12t; 40.6%), C16:0 (22.5%), C17:1ω6c (13.7%) and C17:0 (9.1%). DNA and chemotaxonomic data supported the affiliation of strain BS11T to the genus Sphingosinicella. Strain BS11T could be differentiated genotypically and phenotypically from the recognized species of the genus Sphingosinicella. The novel isolate therefore represents a novel species, for which the name Sphingosinicella ginsenosidimutans sp. nov. is proposed, with the type strain BS11T (=KACC 16619T =JCM 18201T).

Spirosoma montaniterrae sp. nov., an ultraviolet and gamma radiation-resistant bacterium isolated from mountain soil §

A Gram-negative, yellow-pigmented, long-rod shaped bacterial strain designated DY10T was isolated from a soil sample collected at Mt. Deogyusan, Jeonbuk province, South Korea. Optimum growth observed at 30°C and pH 7. No growth was observed above 1% (w/v) NaCl. Comparative 16S rRNA gene sequence analysis showed that strain DY10T belonged to the genus Spirosoma and was distantly related to Spirosoma arcticum R2–35T (91.0%), Spirosoma lingual DSM 74T (90.8%), Spirosoma endophyticum EX36T (90.7%), Spirosoma panaciterrae DSM 21099T (90.5%), Spirosoma rigui WPCB118T (90.2%), Spirosoma spitsbergense DSM 19989T (89.8%), Spirosoma luteum DSM 19990T (89.6%), Spirosoma oryzae RHs22T (89.6%), and Spirosoma radiotolerans DG5AT (89.1%). Strain DY10T showed resistance to gamma and ultraviolet radiation. The chemotaxonomic characteristics of strain DY10T were consistent with those of the genus Spirosoma, with the quinone system with MK-7 as the predominant menaquinone, iso-C15:0, C16:1ω5c, and summed feature3 (C16:1ω7c/C16:1ω6c), and phosphatidylethanolamine as the major polar lipid. The G+C content of the genomic DNA was 53.0 mol%. Differential phenotypic properties with the closely related type strains clearly distinguished strain DY10T from previously described members of the genus Spirosoma and represents a novel species in this genus, for which the name Spirosoma montaniterrae sp. nov. is proposed. The type strain is DY10T (=KCTC 23999T =KEMB 9004–162T =JCM 18492T).

Rhodanobacter aciditrophus sp. nov., an acidophilic bacterium isolated from mine wastewater.

A novel strain (designated sjH1T), characterized as aerobic, Gram-stain-negative, oxidase-positive, catalase-negative, motile and rod-shaped, was isolated from mine wastewater. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain sjH1T belonged to the genus Rhodanobacter. Strain sjH1T was closely related to Rhodanobacter thiooxydans LCS2T (98.0% 16S rRNA gene sequence similarity), Rhodanobacter denitrificans 2APBS1T (97.7%), Rhodanobacter soli DCY45T (97.2%) and Rhodanobacter caeni MJ01T (97.0%). The DNA G+C content of strain sjH1T was 69.2 mol%. DNA-DNA relatedness ( < 60%) indicated that strain sjH1T represents a distinct species that is separate from R. thiooxydans, R. denitrificans, R. soli and R. caeni. The major ubiquinone was Q-8, and major fatty acids were summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), iso-C15 : 0, iso-C17 : 0, iso-C16 : 0 and anteiso-C15 : 0. Based on data from this polyphasic study, it is proposed that sjH1T ( = KCTC 42660T = JCM 30774T) is the type strain of a novel species, Rhodanobacter aciditrophus sp. nov.

Anseongella ginsenosidimutans gen. nov., sp. nov., isolated from soil cultivating ginseng

A Gram-stain-negative, rod-shaped, non-spore-forming, oxidase and catalase-positive, strictly aerobic bacterium, designated strain Gsoil 524T, was isolated from the soil of a ginseng field and subjected to polyphasic taxonomic analysis. Phylogenetic analysis, based on the 16S rRNA gene sequence, placed Gsoil 524T in a distinct lineage in the family Sphingobacteriaceae, sharing 87.2-88.0 % sequence similarity with members of the closely related genera Pedobacter, Mucilaginibacter and Solitalea. Strain Gsoil 524T contained MK-7 as the predominant quinone, and iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 1ω5c as the major fatty acids. Strain Gsoil 524T could be distinguished from the other members of the family Sphingobacteriaceae by a number of chemotaxonomic and phenotypic characteristics. The major polar lipids in strain Gsoil 524T were phosphatidylethanolamine and two unidentified polar lipids. Compared with the standard and reference strains unidentified sphingolipid was also found. Based on this polyphasic taxonomic analysis, strain Gsoil 524T represents a novel species within a novel genus, for which the name Anseongella ginsenosidimutans gen. nov., sp. nov. is proposed. The type strain of Anseongella ginsenosidimutans is Gsoil 524T ( = KACC 14636T = KCTC 22261T = LMG 24494T).

Complete genome sequence of Hymenobacter sedentarius DG5BT, a bacterium resistant to gamma radiation

The ionizing radiation toxicity becomes a primary concern of the world; several exceptional attention was given to the resistance mechanisms of the radiation-resistant bacteria. Hymenobacter sedentarius DG5BT strain isolated from the gamma ray-irradiated soil samples shows resistance against gamma and UV radiation; however, their level of resistance is lower than that of other radiation resistant bacteria. To gain insight of radiation resistance, we carried out the whole genome sequencing of this strain. The genome of DG5BT strain is comprised of 4,868,852 bp (G+C content of 60.96%) including 3,994 protein-coding genes and 55 RNA genes. When compared with other bacteria, there are differences in compositions and copy numbers of several genes involved in DNA repair pathways and defense mechanism against protein damages. In this study, we discuss the implication of such findings concerning other radiation resistant bacteria.

Deinococcus actinosclerus sp. nov., a novel bacterium isolated from soil, South Korea.

Three Gram-stain-positive, catalase- and oxidase-positive coccus- or rod-shaped bacterial strains, designated BM2T, BM4 and BM5, were isolated from soil in South Korea. They showed strong resistance to gamma radiation with a D10 value of 9 kGy but weak UVC resistance. The 16S rRNA sequences of strains BM2T, BM4 and BM5 represent a novel subline within the genus Deinococcus in the family Deinococcaceae. The 16S rRNA gene sequences of strains BM2T, BM4 and BM5 were indistinguishable and showed 98.1-87.3 % similarity with other species of the genus Deinococcus. Strain BM2T exhibited relatively high levels of DNA-DNA hybridization with BM4 (87 ± 0.8 %) and BM5 (92 ± 1.2 %). Meanwhile, it showed a low level of DNA-DNA hybridization ( < 30 %) with other closely related species of the genus Deinococcus. The strains showed the typical chemotaxonomic characteristics of the genus Deinococcus, with the presence of menaquinone 8 as the respiratory quinone; the major fatty acids were summed feature 3 (composed of C16 : 1ω7c/C16 : 1ω6c), C15 : 1ω6c and C16 : 0. The DNA G+C content of strain BM2T was 69.7 mol%. The polar lipid profile included major amounts of phosphatidylglycerol, phosphatidylcholine and an unknown aminolipid. On the basis of phenotypic and genotypic properties, and phylogenetic distinctiveness, strains BM2T, BM4 and BM5 should be classified in a novel species in the genus Deinococcus, for which the name Deinococcus actinosclerus sp. nov. is proposed. The type strain is BM2T ( = KEMB 5401-184T = JCM 30700T); reference strains are BM4 ( = JCM 30701) and BM5 ( = JCM 30702).

Flavisolibacter tropicus sp. nov., isolated from tropical soil.

A Gram-stain-negative, non-motile, deep yellow, rod-shaped bacterium, designated strain LCS9T, was isolated from a soil sample at the tropical zone within the Ecorium of the National Institute of Ecology in Seocheon, central-western Korea. 16S rRNA gene sequence analysis showed that strain LCS9T clustered with members of the genus Flavisolibacter of the family Chitinophagaceae, phylum Bacteroidetes. Sequence similarities between strain LCS9T and the type strains of the genus Flavisolibacter ranged from 94.6 to 94.9 %. Strain LCS9T grew at 10-37 °C (optimum, 25 °C) and at pH 6.0-10.0 (optimum, pH 7); was positive for catalase and oxidase; and negative for nitrate reduction and production of indole. Cells showed pigment absorbance peaks at 451 and 479 nm, and had 0.03 % survival following exposure to 3 kGy gamma radiation. Strain LCS9T had the following chemotaxonomic characteristics: the major quinone was menaquinone-7 (MK-7); the major fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH; polar lipids included phosphoatidylethanolamine, an unidentified aminophospholipid, unidentified aminolipidsand unidentified lipids. The DNA G+C content was 39.4 mol%. Based on polyphasic analysis, the type strain LCS9T (=KCTC 42070T=JCM 19972T) represents a novel species for which the name Flavisolibacter tropicus sp. nov. is proposed. Radiation resistance in the genus Flavisolibacter has not been reported to date, and so this is the first report of low-level radiation resistance of a member of the genus.

Flavisolibacter ginsenosidimutans sp. nov., with ginsenoside-converting activity isolated from soil used for cultivating ginseng.

A Gram-reaction-negative, aerobic, non-motile and rod-shaped bacterial strain designated Gsoil 636T was isolated from soil of a ginseng cultivation field in Pocheon Province, South Korea and its taxonomic position was investigated using a polyphasic approach. Gsoil 636T grew at 18-30 °C and at pH 6.0-8.0 on R2A medium. Gsoil 636T possessed β-glucosidase activity, which was responsible for its ability to transform ginsenoside Rb1 (ones of the dominant active components of ginseng) to F2. On the basis of 16S rRNA gene sequence similarity, Gsoil 636T was shown to belong to the family Chitinophagaceae and to be related to Flavisolibacter ginsengiterrae Gsoil 492T (96.7 % sequence similarity), Flavisolibacter ginsengisoli Gsoil 643T (96.6 %) and Flavisolibacter rigui 02SUJ3T (96.6 %). The G+C content of the genomic DNA was 48.9 %. The predominant respiratory quinone was MK-7 and the major fatty acids were iso-C15 : 0, summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c) and iso-C17 : 0 3-OH. DNA and chemotaxonomic data supported the affiliation of Gsoil 636T to the genus Flavisolibacter. Gsoil 636T could be differentiated genotypically and phenotypically from the species of the genus Flavisolibacter with validly published names. The isolate therefore represents a novel species, for which the name Flavisolibacter ginsenosidimutans sp. nov. is proposed, with the type strain Gsoil 636T (KCTC 22818T = JCM 18197T = KACC 14277T).

Sphingomonas aquatica sp. nov., isolated from tap water

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.

Hymenobacter sedentarius sp. nov., isolated from a soil

A novel Gram-negative and red-pinkish bacterium designated DG5BT was isolated from a dry soil. Cells were rods that were catalase- and oxidase-positive, and non-motile. The strain was found to grow at temperatures from 10 to 30°C (optimum 25°C) and pH 6.0–8.0, (optimum pH 7) on R2A broth. 16S rRNA gene sequence (1,452 bp) analysis of this strain identified it as a member of the genus Hymenobacter that belongs to the class Cytophagia. The highest gene sequence similarities were with Hymenobacter arizonensis OR362-8T (98.3%), Hymenobacter humi DG31AT (97.6%), and Hymenobacter glaciei VUG-A130T (96.6%). Strain DG5BT exhibited <70% DNA-DNA relatedness with H. arizonensis (34.7 ± 7.0%; reciprocally, 29.7 ± 1.2%) and H. humi (39.4 ± 4.3%; reciprocally, 39.5 ± 3.3%) as a different genomic species, and its genomic DNA G+C content was 59.8%. Strain DG5BT had the following chemotaxonomic characteristics: the major fatty acids are iso-C15:0, anteiso-C15:0, C16:1ω5c, and summed feature 3 (C16:1ω7c / C16:1ω6c); polar lipid profile contained phosphatidylethanolamine (PE), unknown aminophospholipid (APL), unknown glycolipids (GL), unknown phospholipids (PL), and unknown polar lipids (L); the major quinone is MK-7. The absorbance peak of pigment is at 481.0 nm. Strain DG5BT showed low-level resistance to gamma-ray irradiation. Phenotypic, chemotaxonomic, and genotypic properties indicated that isolate DG5BT represents a novel species within the genus Hymenobacter for which the name Hymenobacter sedentarius sp. nov. is proposed. The type strain is DG5BT (=KCTC 32524T =JCM 19636T).