Long-term cell fate and functional maintenance of human hepatocyte through stepwise culture configuration.

Human hepatocyte culture system represents by far the most physiologically relevant model for our understanding of liver biology and diseases; however, its versatility has been limited due to the rapid and progressive loss of genuine characteristics, indicating the inadequacy of in vitro milieu for fate maintenance. This study, therefore, is designed to define environmental requirements necessary to sustain the homeostasis of terminally differentiated hepatocytes. Our study reveals that the supplementation of dimethyl sulfoxide (DMSO) is indispensable in mitigating fate deterioration and promoting adaptation to the in vitro environment, resulting in the restoration of tight cell-cell contact, cellular architecture, and polarity. The morphological recovery was overall accompanied by the restoration of hepatocyte marker gene expression, highlighting the interdependence between the cellular architecture and the maintenance of cell fate. However, beyond the recovery phase culture, DMSO supplementation is deemed detrimental due to the potent inhibitory effect on a multitude of hepatocyte functionalities while its withdrawal results in the loss of cell fate. In search of DMSO substitute, our screening of organic substances led to the identification of dimethyl sulfone (DMSO2), which supports the long-term maintenance of proper morphology, marker gene expression, and hepatocytic functions. Moreover, hepatocytes maintained DMSO2 exhibited clinically relevant toxicity in response to prolonged exposure to xenobiotics as well as alcohol. These observations suggest that the stepwise culture configuration consisting of the consecutive supplementation of DMSO and DMSO2 confers the microenvironment essential for the fate and functional maintenance of terminally differentiated human hepatocytes.

Phosphoenolpyruvate depletion mediates both growth arrest and drug tolerance of Mycobacterium tuberculosis in hypoxia.

Mycobacterium tuberculosis (Mtb) infection is difficult to treat because Mtb spends the majority of its life cycle in a nonreplicating (NR) state. Since NR Mtb is highly tolerant to antibiotic effects and can mutate to become drug resistant (DR), our conventional tuberculosis (TB) treatment is not effective. Thus, a novel strategy to kill NR Mtb is required. Accumulating evidence has shown that repetitive exposure to sublethal doses of antibiotics enhances the level of drug tolerance, implying that NR Mtb is formed by adaptive metabolic remodeling. As such, metabolic modulation strategies to block the metabolic remodeling needed to form NR Mtb have emerged as new therapeutic options. Here, we modeled in vitro NR Mtb using hypoxia, applied isotope metabolomics, and revealed that phosphoenolpyruvate (PEP) is nearly completely depleted in NR Mtb. This near loss of PEP reduces PEP-carbon flux toward multiple pathways essential for replication and drug sensitivity. Inversely, supplementing with PEP restored the carbon flux and the activities of the foregoing pathways, resulting in growth and heightened drug susceptibility of NR Mtb, which ultimately prevented the development of DR. Taken together, PEP depletion in NR Mtb is associated with the acquisition of drug tolerance and subsequent emergence of DR, demonstrating that PEP treatment is a possible metabolic modulation strategy to resensitize NR Mtb to conventional TB treatment and prevent the emergence of DR.

Oncogenic human herpesvirus hijacks proline metabolism for tumorigenesis.

Three-dimensional (3D) cell culture is well documented to regain intrinsic metabolic properties and to better mimic the in vivo situation than two-dimensional (2D) cell culture. Particularly, proline metabolism is critical for tumorigenesis since pyrroline-5-carboxylate (P5C) reductase (PYCR/P5CR) is highly expressed in various tumors and its enzymatic activity is essential for in vitro 3D tumor cell growth and in vivo tumorigenesis. PYCR converts the P5C intermediate to proline as a biosynthesis pathway, whereas proline dehydrogenase (PRODH) breaks down proline to P5C as a degradation pathway. Intriguingly, expressions of proline biosynthesis PYCR gene and proline degradation PRODH gene are up-regulated directly by c-Myc oncoprotein and p53 tumor suppressor, respectively, suggesting that the proline-P5C metabolic axis is a key checkpoint for tumor cell growth. Here, we report a metabolic reprogramming of 3D tumor cell growth by oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV), an etiological agent of Kaposi's sarcoma and primary effusion lymphoma. Metabolomic analyses revealed that KSHV infection increased nonessential amino acid metabolites, specifically proline, in 3D culture, not in 2D culture. Strikingly, the KSHV K1 oncoprotein interacted with and activated PYCR enzyme, increasing intracellular proline concentration. Consequently, the K1-PYCR interaction promoted tumor cell growth in 3D spheroid culture and tumorigenesis in nude mice. In contrast, depletion of PYCR expression markedly abrogated K1-induced tumor cell growth in 3D culture, not in 2D culture. This study demonstrates that an increase of proline biosynthesis induced by K1-PYCR interaction is critical for KSHV-mediated transformation in in vitro 3D culture condition and in vivo tumorigenesis.

Evaluation of anatomical and histological characteristics of human peripheral nerves: as an effort to develop an efficient allogeneic nerve graft.

Management of peripheral nerve defects is a complicated problem in clinical contexts. Autologous nerve grafting, a gold standard for surgical treatment, has been well known to have several limitations, such as donor site morbidity, a limited amount of available donor tissue, and size mismatches. Acellular nerve allografts (ANAs) have been developed as an alternative and have been applied clinically with favorable outcomes. However, because of the limited availability of commercialized ANAs due to supplier-related issues and high costs, efforts continue to produce alternative sources for ANAs. The present study evaluated the anatomical and histological characteristics of human peripheral nerves using 25 donated human cadavers. The length, diameter, and branching points of various peripheral nerves (median, ulnar, tibial, lateral femoral cutaneous, saphenous, and sural nerves) in both the upper and lower extremities were evaluated. The cross-sectional area (CSA), ratio of fascicular area, and numbers of fascicles were also evaluated via histologic analysis. CSA, the ratio of fascicular area, and the number of fascicles were analyzed statistically in correlation with demographic data (age, sex, height, weight, BMI). The mean length of all evaluated nerves ranged from 17.1 to 41.4 cm, and the mean diameter of all evaluated nerves ranged from 1.2 to 4.9 mm. Multiple regression analysis revealed correlations between the ratio of fascicular area and sex (p = 0.005) and BMI (p = 0.024) (R2 = 0.051). The results of the present study will be helpful in selecting necessary nerve allograft sources while considering the characteristics of each nerve in the upper and lower extremities during ANAs production.

Chiroptical Performances in Self-Assembled Hierarchical Nanosegregated Chiral Intermediate Phases Composed of Two Different Achiral Bent-Core Molecules.

In this paper, chiral intermediate phases composed of two achiral molecules are fabricated by utilizing nanophase separation and molecular hierarchical self-organization. An achiral bent-core guest molecule, exhibiting a calamitic nematic and a dark conglomerate phase according to the temperature, is mixed with another achiral bent-core host molecule possessing a helical nanofilament to separate the phases between them. Two nanosegregated phases are identified, and considerable chiroptical changes, such as circular dichroism and circularly polarized luminescence, are detected at the transition temperatures between the different nanophase-separated states. The nanosegregated chiral phase-wherein the helical nanofilament and dark conglomerate phases are phase-separated-exhibits the highest chiroptical intensities. The luminescence dissymmetry factor, |glum|, in this phase is amplified by an order of magnitude compared with that of another nanosegregated phase, wherein the helical nanofilament and nematic phases are phase-separated.

Control of the Induced Handedness of Helical Nanofilaments Employing Cholesteric Liquid Crystal Fields.

In this paper, a simple and powerful method to control the induced handedness of helical nanofilaments (HNFs) is presented. The nanofilaments are formed by achiral bent-core liquid crystal molecules employing a cholesteric liquid crystal field obtained by doping a rod-like nematogen with a chiral dopant. Homochiral helical nanofilaments are formed in the nanophase-separated helical nanofilament/cholesteric phase from a mixture with a cholesteric phase. This cholesteric phase forms at a temperature higher than the temperature at which the helical nanofilament in a bent-core molecule appears. Under such conditions, the cholesteric liquid crystal field acts as a driving force in the nucleation of HNFs, realizing a perfectly homochiral domain consisting of identical helical nanofilament handedness.

Proteomic Analysis of Hippocampus in a Mouse Model of Depression Reveals Neuroprotective Function of Ubiquitin C-terminal Hydrolase L1 (UCH-L1) via Stress-induced Cysteine Oxidative Modifications.

Chronic physical restraint stress increases oxidative stress in the brain, and dysregulation of oxidative stress can be one of the causes of major depressive disorder. To understand the underlying mechanisms, we undertook a systematic proteomic analysis of hippocampus in a chronic restraint stress mouse model of depression. Combining two-dimensional gel electrophoresis (2D-PAGE) for protein separation with nanoUPLC-ESI-q-TOF tandem mass spectrometry, we identified sixty-three protein spots that changed in the hippocampus of mice subjected to chronic restraint stress. We identified and classified the proteins that changed after chronic stress, into three groups respectively functioning in neural plasticity, metabolic processes and protein aggregation. Of these, 5 proteins including ubiquitin C-terminal hydrolase L1 (UCH-L1), dihydropyrimidinase-related protein 2 (DPYL2), haloacid dehalogenase-like hydrolase domain-containing protein 2 (HDHD2), actin-related protein 2/3 complex subunit 5 (ARPC5) and peroxiredoxin-2 (PRDX2), showed pI shifts attributable to post-translational modifications. Further analysis indicated that UCH-L1 underwent differential oxidations of 2 cysteine residues following chronic stress. We investigated whether the oxidized form of UCH-L1 plays a role in stressed hippocampus, by comparing the effects of UCH-L1 and its Cys mutants on hippocampal cell line HT-22 in response to oxidative stress. This study demonstrated that UCH-L1 wild-type and cysteine to aspartic acid mutants, but not its cysteine to serine mutants, afforded neuroprotective effects against oxidative stress; there were no discernible differences between wild-type UCH-L1 and its mutants in the absence of oxidative stress. These findings suggest that cysteine oxidative modifications of UCH-L1 in the hippocampus play key roles in neuroprotection against oxidative stress caused in major depressive disorder.

Heterogeneous nuclear ribonucleoprotein K inhibits heat shock-induced transcriptional activity of heat shock factor 1.

When cells are exposed to heat shock and various other stresses, heat shock factor 1 (HSF1) is activated, and the heat shock response (HSR) is elicited. To better understand the molecular regulation of the HSR, we used 2D-PAGE-based proteome analysis to screen for heat shock-induced post-translationally modified cellular proteins. Our analysis revealed that two protein spots typically present on 2D-PAGE gels and containing heterogeneous nuclear ribonucleoprotein K (hnRNP K) with trioxidized Cys132 disappeared after the heat shock treatment and reappeared during recovery, but the total amount of hnRNP K protein remained unchanged. We next tested whether hnRNP K plays a role in HSR by regulating HSF1 and found that hnRNP K inhibits HSF1 activity, resulting in reduced expression of hsp70 and hsp27 mRNAs. hnRNP K also reduced binding affinity of HSF1 to the heat shock element by directly interacting with HSF1 but did not affect HSF1 phosphorylation-dependent activation or nuclear localization. hnRNP K lost its ability to induce these effects when its Cys132 was substituted with Ser, Asp, or Glu. These findings suggest that hnRNP K inhibits transcriptional activity of HSF1 by inhibiting its binding to heat shock element and that the oxidation status of Cys132 in hnRNP K is critical for this inhibition.

Larkinella knui sp. nov., isolated from soil.

A Gram-stain-negative, motile by gliding, rod-shaped, aerobic bacterium, designated 15J6-3T6T, was isolated from a soil sample collected from Jeju Island, South Korea, and characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 15J6-3T6T belongs to the family Cytophagaceae and is related to Larkinella harenae 15J9-9T (93.9 % similarity), Larkinella arboricola Z0532T (93.6 %), Larkinella bovis M2TB15T (93.3 %), and Larkinella insperata LMG 22510T (93.3 %). The DNA G+C content of strain 15J6-3T6T was 50.6 mol%. The detection of phosphatidylethanolamine and an unidentified polar lipid as major polar lipids, menaquinone-7 as the predominant quinone, and C16 : 1ω5c, iso-C15 : 0, and iso-C17 : 0 3-OH as the major fatty acids also supports the affiliation of the isolate to the genus Larkinella. Based on its phenotypic properties and phylogenetic distinctiveness, we propose that strain 15J6-3T6T should be classified in the genus Larkinella as a representative of a novel species, for which the name Larkinella knui sp. nov. is proposed. The type strain is 15J6-3T6T (=KCTC 42998T=JCM 31989T).

Spirosoma humi sp. nov., Isolated from Soil in South Korea.

A Gram-stain-negative, non-motile, rod-shaped, aerobic bacterial strain, designated S7-4-1T, was isolated from soil in Gyeongsangnam-do, South Korea and characterized using a polyphasic approach to determine its taxonomic position. Phylogenic analysis based on the 16S rRNA gene sequence showed that strain S7-4-1T belonged to the family Cytophagaceae and was most closely related to Spirosoma fluviale MSd3T (96.2%), 'Spirosoma radiotolerans' DG5A (96.0%), Spirosoma pulveris JSH5-14T (95.9%), and Spirosoma linguale DSM 74T (95.8%). The G+C content of the genomic DNA of the isolate was 49.0 mol%. The strain contained summed feature 3 (C16:1 ω7c/C16:1 ω6c; 41.0%), C16:1 ω5c (24.9%), and C15:0 iso (9.3%) as the major fatty acids, menaquinone MK-7 as the predominant respiratory quinone, and phosphatidylethanolamine and an unidentified aminophospholipid as the main polar lipids, which supported its affiliation with the genus Spirosoma. The results of physiological and biochemical tests allowed the genotypic and phenotypic differentiation of the isolate from recognized Spirosoma species. On the basis of its phenotypic properties, genotypic distinctiveness, and chemotaxonomic features, strain S7-4-1T represents a novel species of the genus Spirosoma, for which the name Spirosoma humi sp. nov. is proposed. The type strain is S7-4-1T (= KCTC 52729T = JCM 32132T).

Spirosoma terrae sp. nov., Isolated from Soil from Jeju Island, Korea.

The taxonomic position of bacterial strain, designated 15J9-4T, recovered from a beach soil sample on Jeju Island, South Korea, was established using a polyphasic approach. Strain 15J9-4T was assigned to phylum Bacteroidetes within the family Cytophagaceae based on 16S rRNA gene similarities. The closest phylogenetic relatives with validly published names were Spirosoma panaciterrae Gsoil 1519T (94.2% similarity) and Spirosoma luteolum 16F6ET (94.1%). Cells were rod-shaped, Gram-stain-negative, and non-motile. The isolate grew on NA, R2A, TSA, and LB agar. The temperature limits for growth were 10 and 30 °C with an optimum at 25 °C and the pH range was 7-8. Menaquinone MK-7 was the predominant respiratory quinone. The major cellular fatty acids comprised summed feature 3 (C16:1 ω6c/C16:1 ω7c, 30.2%), C16:1 ω5c (22.2%), iso C15:0 (12.9%), and C16:0 (8.8%). Phosphatidylethanolamine was identified as the major polar lipid. The G+C content of the genomic DNA was 48.4 mol%. The results obtained from the polyphasic analyses allowed for the genotypic and phenotypic differentiation of strain 15J9-4T from recognized Spirosoma species. Therefore, the isolate is considered to represent a novel species in the genus Spirosoma, for which the name Spirosoma terrae sp. nov. is proposed. The type strain is 15J9-4T (= KCTC 52035T = JCM 31994T).

Spirosoma harenae sp. nov., a Bacterium Isolated from a Sandy Beach.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J8-9T, was isolated from a sandy beach in Jeju Island, South Korea. The isolate was able to grow between 10 and 30 °C, pH 5-8, and in presence of 0-1% (w/v) NaCl. Based on 16S rRNA gene phylogenetic analysis, the novel strain was closely related to members of the genus Spirosoma (96.1-90.9% similarities) and showed highest sequence similarity to Spirosoma panaciterrae DSM 21099T (96.1%). The G + C content of the genomic DNA of strain 15J8-9T was 45.1 mol%. The isolate contained menaquinone MK-7 as the predominant respiratory quinone, phosphatidylethanolamine as the major polar lipid, and summed feature 3 (C16:1 ω6c/C16:1 ω7c; 28.0%), C16:1 ω5c (23.4%), iso-C15:0 (13.5%), and C16:0 (11.5%) as the major fatty acids that supported the affiliation of strain 15J8-9T to the genus Spirosoma. The isolate could be differentiated clearly from recognized Spirosoma species on the basis of several phenotypic, genotypic and chemotaxonomic features. Therefore, strain 15J8-9T is considered to represent a novel species of the genus the genus Spirosoma, for which the name Spirosoma harenae sp. nov. is proposed. The type strain is 15J8-9T (= KCTC 52030T = JCM 31993T).

Hymenobacter aquaticus sp. nov., a radiation-resistant bacterium isolated from a river.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F3PT, was isolated from the Han River, South Korea, and characterized taxonomically using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed 16F3PT to be within the genus Hymenobacter, and most closely related to Hymenobacterchitinivorans Txc1T (98.62 %) and Hymenobacterelongatus VUG-A112T (98.46 %). The phylogenetic distance from other species of the genus Hymenobacter with validly published names was greater than 4 % (i.e. sequence similarity was less than 96.0 %). Chemotaxonomic data also supported the classification of strain 16F3PT within the genus Hymenobacter. C16 : 0 (19.8 %), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 15.4 %) and iso-C15 : 0 (13.0 %) were the major fatty acids, MK-7 was the predominant respiratory quinone, and phosphatidylethanolamine was the major polar lipid. The G+C content of the genomic DNA of strain 16F3PT was 61.9 mol%. DNA-DNA hybridization experiments showed that the values for DNA-DNA relatedness between strain 16F3PT and the phylogenetically closest neighbours were below 19 %. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 16F3PT represents a novel species of the genus Hymenobacter, for which the name Hymenobacter aquaticus sp. nov. is proposed. The type strain is 16F3PT (=KCTC 52194T=JCM 31653T).

Flaviaesturariibacter terrae sp. nov., isolated from mountain soil.

A Gram-stain-negative, aerobic, rod-shaped, non-motile and pale yellow-pigmented bacterial strain, designated as HY03T, was isolated from mountain soil. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HY03T belonged to the family Chitinophagaceae in the phylum Bacteroidetes and was most closely related to Flaviaesturariibacter amylovorans GCR0105T at a similarity of 95.4 %. The genomic DNA G+C content of strain HY03T was 43.2 mol%. The major fatty acids of the isolate were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The polar lipid profile of strain HY03T consisted of the major compound phosphatidylethanolamine and moderate amounts of an unknown aminophospholipid, unknown phospholipids and unknown lipids. The predominant respiratory quinone was menaquinone 7 (MK-7). Phylogenetic, genotypic, phenotypic and chemotaxonomic characteristics indicated that strain HY03T represents a novel species within the genus Flaviaesturariibacter, for which the name Flaviaesturariibacter terrae sp. nov. is proposed. The type strain is HY03T (=KCTC 52511T=JCM 31723T).

Adhaeribacter terrae sp. nov., a novel bacterium isolated from soil.

Strain HY02T was isolated from a soil sample collected at Namyangju-si, Gyeonggi-do, Republic of Korea. Cells of this strain were observed to be Gram-stain-negative, short and rod-shaped. Colonies were red in colour. A 16S rRNA gene sequence analysis identified this strain as a member of the genus Adhaeribacter in the family Cytophagaceae, with the highest level of 16S rRNA gene sequence similarity to Adhaeribacter terreus DNG6T (98.08 %). This strain was positive for oxidase but negative for catalase activity and acid production from glucose. Growth of strain HY02T was observed at 15-30 °C, pH 7-8 and in the presence of 0-1 % NaCl. The isolate contained MK-7 as the predominant respiratory quinone, and C18 : 0, iso-C15 : 0, summed feature 4 (anteiso-C17 : 1 B/iso-C17 : 1 I) and C16 : 0 were the major fatty acids. The major polar lipid was phosphatidylethanolamine. The genomic DNA G+C content of strain HY02T was 44.0 mol%. Phenotypic and chemotaxonomic data supported the affiliation of strain HY02T with the genus Adhaeribacter. However, strain HY02T exhibited a relatively low level of DNA-DNA relatedness with A. terreus(16.3±3.5 %). Based on its phenotypic and genotypic properties, together with its phylogenetic distinctiveness, strain HY02T should be considered a representative of a novel species in the genus Adhaeribacter, for which the name Adhaeribacter terrae sp. nov. is proposed. The type strain is HY02T (=KCTC 52512T=JCM 31652T).

Larkinella ripae sp. nov., isolated from seashore soil.

Strain 15J11-11T was isolated from soil collected at the seashore and was Gram-staining-negative, short-rod-shaped, gliding and pale-pink pigmented. Flexirubin-type pigments were absent. The isolate grew at a temperature range of 15 to 30 °C and a pH range of 7 to 8. Comparative 16S rRNA gene sequence studies showed that strain 15J11-11T belonged to the genus Larkinella within the phylum Bacteroidetes and was most closely related to Larkinella arboricola Z0532T (95.6 %), Larkinella bovis M2TB15T (95.4 %), and Larkinella insperata LMG 22510T (95.2 %). The genomic DNA G+C content of strain 15J11-11T was 53.2 mol%. The strain contained phosphatidylethanolamine, phosphatidylserine, an unidentified aminophospholipid and two unidentified polar lipids as the major polar lipids; menaquinone-7 as the predominant quinone and C16 : 1ω5c, iso-C15 : 0 and iso-C17 : 0 3-OH as the major fatty acids which supported the affiliation of strain 15J11-11T to the genus Larkinella. Based on its phenotypic properties and phylogenetic distinctiveness, strain 15J11-11T represents a novel species of the genus Larkinella, for which the name Larkinella ripae sp. nov. is proposed. The type strain is 15J11-11T (=KCTC 42996T=JCM 31657T).

Spirosoma koreense sp. nov., a species of the family Cytophagaceae isolated from beach soil.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J8-5T, was isolated from beach soil on Jeju Island, Republic of Korea. The isolate grew at 10-37 °C (optimal 25 °C), pH 6-8 (optimal pH 7) and in the presence of 0-1 % (w/v) NaCl. The results of comparative 16S rRNA gene sequence analysis indicated that strain 15J8-5T represented a member of the family Cytophagaceae, phylum Bacteroidetes and was most closely related to Spirosoma knui 15J8-12T (93.1 % similarity), Spirosoma spitsbergense SPM-9T (93.1 %) and Spirosoma endophyticum EX36T (93.1 %). The G+C content of the genomic DNA of the novel strain was 48.0 mol%. The isolate contained menaquinone MK-7 as the predominant respiratory quinone, phosphatidylethanolamine as the major polar lipid, and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 32.8 %), C16 : 1ω5c (24.8 %) and C16 : 0 (11.7 %) as the major fatty acids, which supported the affiliation of strain 15J8-5T to the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J8-5T from members of the genus Spirosoma. Based on its phenotypic properties and phylogenetic distinctiveness, strain 15J8-5T represents a novel species of the genus Spirosoma, for which the name Spirosomakoreense sp. nov. is proposed. The type strain is 15J8-5T (=KCTC 52027T=JCM 31992T).

Spirosoma litoris sp. nov., a bacterium isolated from beach soil.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J16-2T3AT, was isolated from beach soil on Jeju Island, South Korea. Strain 15J16-2T3AT grew at 10-37 °C (optimum growth at 25 °C) and pH 6.5-8.5 (optimum growth at pH 7). Based on 16S rRNA gene phylogenetic analysis, the novel strain was closely related to members of the genus Spirosoma(94.8-89.9 % similarities) and formed a separate branch within the genus together with Spirosoma luteolum 16F6ET in neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees. The G+C content of the genomic DNA of strain 15J16-2T3AT was 47.6 mol%. The detection of menaquinone MK-7 as the predominant respiratory quinone, a fatty acid profile with summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 35.5 %), C16 : 1ω5c (26.6 %), and iso C15 : 0 (10.1 %) as the major components, phosphatidylethanolamine and unidentified aminophospholipid as the major polar lipids also support the affiliation of strain 15J16-2T3AT with the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J16-2T3AT from members the genus Spirosoma. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 15J16-2T3AT represents a novel species of the genus Spirosoma, for which the name Spirosoma litoris sp. nov. is proposed. The type strain is 15J16-2T3AT (=KCTC 52029T=JCM 31999T).

Hymenobacter seoulensis sp. nov., isolated from river water.

A Gram-stain-negative, aerobic, rod-shaped, non-motile and pink-pigmented bacterial strain, designated 16F7GT, was isolated from river water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 16F7GT belongs to the genus Hymenobacter. The 16S rRNA gene sequence similarity to members of the genus Hymenobacter ranged from 90.5 to 97.4 %, and the most closely related strains were Hymenobacter rigui WPCB131T (97.4 %) and Hymenobacter xinjiangensis X2-1gT (97.3 %). Strain 16F7GT had <70 % DNA-DNA relatedness with H. rigui (32.8±7.8 %) and H. xinjiangensis (30.2±6.2 %), indicating that it represents a novel genospecies. Cells were catalase- and oxidase-positive. The genomic DNA G+C content was 56.6 mol%. The major fatty acids were summed feature 4 (C17 : 1iso I/C17 : 1 anteiso B; 19.8 %), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 18.4 %), C15 : 0 iso (17.0 %), C16 : 1ω5c (11.8 %) and C15 : 0 anteiso (9.8 %). The major polar lipid was phosphatidylethanolamine and the predominant respiratory quinone was menaquinone 7 (MK-7). Based on the phylogenetic, phenotypic, genotypic and chemotaxonomic analyses, it is concluded that strain 16F7GT represents a novel species within the genus Hymenobacter, for which the name Hymenobacter seoulensis sp. nov. is proposed. The type strain is 16F7GT (=KCTC 52197T=JCM 31655T).

Spirosoma knui sp. nov., a radiation-resistant bacterium isolated from the Han River.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J8-12T, was isolated from a water sample after exposure to 3 kGy of gamma radiation. The strain showed resistance to gamma radiation with a dose required to reduce the bacterial population 10 fold (D10) value of 4.7 kGy. The results of comparative 16S rRNA gene sequence analysis indicated that strain 15J8-12T represented a member of the family Cytophagaceae, phylum Bacteroidetes, and was most closely related to 'Spirosomafluminis' 15J17 (97.92 %) and Spirosoma arcticum R2-35T (92.22 %). The G+C content of the genomic DNA of 15J8-12T was 51.3 mol%. The detection of menaquinone MK-7 as the predominant respiratory quinone, a fatty acid profile with summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 40.5 %), C16 : 1ω5c (35.3 %), C15 : 0 iso (6.9 %) and C16 : 0 (6.8 %) as the major components and phosphatidylethanolamine as the major polar lipid also supported the affiliation of 15J8-12T with the genus Spirosoma. The DNA-DNA relatedness between 15J8-12T and 'Spirosoma fluminis' 15J17 was 27.8 %. On the basis of its phenotypic and genotypic properties, together with its phylogenetic distinctiveness, 15J8-12T should be considered to be a representative of a novel species of the genus Spirosoma, for which the name Spirosoma knui sp. nov. is proposed. The type strain is 15J8-12T (=KCTC 52510T=JCM 31407T).