Structural and functional characterization of a monoclonal antibody blocking TIGIT.

TIGIT is an immune checkpoint receptor that is expressed on subsets of activated T cells and natural killer (NK) cells. Several ligands for TIGIT, including poliovirus receptor (PVR), are expressed on cancer cells and mediate inhibitory signaling to suppress antitumor activities of the immune cells. Many studies support that the TIGIT signaling is a potential target for cancer immunotherapy. We developed an IgG4-type monoclonal antibody against human TIGIT, designated as MG1131, using a phage display library of single-chain variable fragments (scFvs). MG1131 interacts with TIGIT much more tightly than PVR does. The crystal structure of a scFv version of MG1131 bound to TIGIT was determined, showing that MG1131 could block the PVR-TIGIT interaction and thus the immunosuppressive signaling of TIGIT. Consistently, MG1131 is bound to TIGIT-expressing cells and interferes with PVR binding to these cells. Moreover, MG1131 increased NK cell-mediated tumor killing activities, inhibited immunosuppressive activity of regulatory T (Treg) cells from healthy donors, and restored interferon-γ secretion from peripheral blood mononuclear cells derived from multiple myeloma patients. MG1131 also increased T cell infiltration to the tumor site and inhibited tumor growth in mice. Collectively, these data indicate that MG1131 modulates the effector functions of T cells and NK cells positively and Treg cells negatively.

The Protective Effect of Edible Bird's Nest against the Immune-senescence Process of UVB-irradiated Hairless Mice.

Edible bird's nest (EBN) is a nutritious food with many beneficial effects, including protecting cells against oxidation and infection due to wounds, bacteria or viruses. EBN has shown antiaging, anti-inflammatory and wound-healing properties in skin cells. Here, we investigated whether EBN has protective effects against photoaging, inflammation and immune-senescence in hairless mice treated with UVB irradiation. The skin thickness was lower in mice on an EBN diet than in mice treated with UVB alone. The level of hydration was significantly increased, while the index of transepidermal water loss decreased, in groups on the EBN diet. EBN also reduced erythema index in UVB-irradiated mice. At the molecular level, skin elasticity and antiaging are associated with high expression of elastin, collagen and filaggrin and low expression of the membrane metalloproteinases, MMP-1 and MMP-2. Inflammatory markers such as interleukins, IL-1ß and IL-6, and TNF-α decreased significantly in the EBN groups. Caspase-3, an important factor in the apoptotic pathway and in congenital and adaptive immune responses, decreased in the EBN groups. Moreover, EBN diminished the overexpression of immunoglobulin E and elevated mast cell counts in UVB-irradiated mice. Overall, these findings suggest that EBN protects skin against aging and alleviates inflammation in UVB-irradiated hairless mice.

Dysfunction of NMDA receptors in neuronal models of an autism spectrum disorder patient with a DSCAM mutation and in Dscam-knockout mice.

Heterogeneity in the etiopathology of autism spectrum disorders (ASD) limits the development of generic remedies, requires individualistic and patient-specific research. Recent progress in human-induced pluripotent stem cell (iPSC) technology provides a novel platform for modeling ASDs for studying complex neuronal phenotypes. In this study, we generated telencephalic induced neuronal (iN) cells from iPSCs derived from an ASD patient with a heterozygous point mutation in the DSCAM gene. The mRNA of DSCAM and the density of DSCAM in dendrites were significantly decreased in ASD compared to control iN cells. RNA sequencing analysis revealed that several synaptic function-related genes including NMDA receptor subunits were downregulated in ASD iN cells. Moreover, NMDA receptor (R)-mediated currents were significantly reduced in ASD compared to control iN cells. Normal NMDA-R-mediated current levels were rescued by expressing wild-type DSCAM in ASD iN cells, and reduced currents were observed by truncated DSCAM expression in control iN cells. shRNA-mediated DSCAM knockdown in control iN cells resulted in the downregulation of an NMDA-R subunit, which was rescued by the overexpression of shRNA-resistant DSCAM. Furthermore, DSCAM was co-localized with NMDA-R components in the dendritic spines of iN cells whereas their co-localizations were significantly reduced in ASD iN cells. Levels of phospho-ERK1/2 were significantly lower in ASD iN cells, suggesting a potential mechanism. A neural stem cell-specific Dscam heterozygous knockout mouse model, showing deficits in social interaction and social memory with reduced NMDA-R currents. These data suggest that DSCAM mutation causes pathological symptoms of ASD by dysregulating NMDA-R function.

Mixture of enzyme-processed Panax ginseng and Gastrodia elata extract prevents UVB-induced decrease of procollagen type 1 and increase of MMP-1 and IL-6 in human dermal fibroblasts.

According to the previously described anti-photoaging effect of the enzyme-processed Panax ginseng extract and Gastrodia elata extract, we hypothesized that the combination of the two extracts would have superior effect to protect human skin from UVB radiation. Besides, the mixture of active components isolated from herbal extracts, ginsenoside F2, and α-gastrodin was investigated on the photo-protective capability. The expression of aging-related markers including matrix metalloproteinase-1 (MMP-1), interleukin-6 (IL-6), and procollagen type 1 was evaluated using ELISA kits. It was reported that the herbal extract at a Panax ginseng extract to Gastrodia elata extract ratio of 1:10 (w/w) and the compound mixture with equal proportion of ginsenoside F2 and α-gastrodin exhibited significant inhibition of MMP-1 and IL-6 production, and marked upregulation of procollagen type 1 formation. Thus, the combination of either the enzyme-processed herbal extracts or their active components would enhance the properties of prevention and treatment of UVB-induced skin damage.

Cohen Syndrome Patient iPSC-Derived Neurospheres and Forebrain-Like Glutamatergic Neurons Reveal Reduced Proliferation of Neural Progenitor Cells and Altered Expression of Synapse Genes.

Cohen syndrome (CS), a rare autosomal recessive disorder, has been associated with genetic mutations in the VPS13B gene, which regulates vesicle-mediated protein sorting and transport. However, the cellular mechanism underlying CS pathogenesis in patient-derived human neurons remains unknown. We identified a novel compound heterozygous mutation, due to homozygous variation of biparental origin and heterozygous variation inherited from the father, in the VPS13B gene in a 20-month-old female patient. To understand the cellular pathogenic mechanisms, we generated induced pluripotent stem cells (iPSCs) from the fibroblasts of the CS patient. The iPSCs were differentiated into forebrain-like functional glutamatergic neurons or neurospheres. Functional annotation from transcriptomic analysis using CS iPSC-derived neurons revealed that synapse-related functions were enriched among the upregulated and downregulated genes in the CS neurons, whereas processes associated with neurodevelopment were enriched in the downregulated genes. The developing CS neurospheres were small in size compared to control neurospheres, likely due to the reduced proliferation of SOX2-positive neural stem cells. Moreover, the number of SV2B-positive puncta and spine-like structures was significantly reduced in the CS neurons, suggesting synaptic dysfunction. Taking these findings together, for the first time, we report a potential cellular pathogenic mechanism which reveals the alteration of neurodevelopment-related genes and the dysregulation of synaptic function in the human induced neurons differentiated from iPSCs and neurospheres of a CS patient.

Identification of a novel Shank2 transcriptional variant in Shank2 knockout mouse model of autism spectrum disorder.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders that are highly heterogeneous in clinical symptoms as well as etiologies. Mutations in SHANK2 are associated with ASD and accordingly, Shank2 knockout mouse shows ASD-like behavioral phenotypes, including social deficits. Intriguingly, two lines of Shank2 knockout (KO) mouse generated by deleting different exons (exon 6-7 or exon 7) showed distinct cellular phenotypes. Previously, we compared gene expressions between Shank2 KOs lacking exon 6-7 (e6-7 KO) and KOs lacking exon 7 (e7 KO) by performing RNA-seq. In this study, we expanded transcriptomic analyses to identify novel transcriptional variants in the KO mice. We found prominent expression of a novel exon (exon 4' or e4') between the existing exons 4 and 5 in the Shank2 e6-7 KO model. Expression of the transcriptional variant harboring this novel exon was confirmed by RT-PCR and western blotting. These findings suggest that the novel variant may function as a modifier gene, which contributes to the differences between the two Shank2 mutant lines. Furthermore, our result further represents an example of genetic compensation that may lead to phenotypic heterogeneity among ASD patients with mutations in the same gene.

Edgeworthia papyrifera Regulates Osteoblast and Osteoclast Differentiation In Vitro and Exhibits Anti-osteoporosis Activity in Animal Models of Osteoporosis.

Osteoporosis is a clinical condition characterized by low bone strength that leads to an increased risk of fracture. Strategies for the treatment of osteoporosis involve inhibition of bone resorption by osteoclasts and an increase of bone formation by osteoblasts. Here, we identified the extract derived from the stem part of Edgeworthia papyrifera that enhanced differentiation of MC3T3-E1 cells to osteoblast-like cells and inhibited osteoclast differentiation of RAW 264.7 cells in vitro. In support of our observation, rutin and daphnoretin, which were previously reported to inhibit osteoclast differentiation, were identified in E. papyrifera extract. In an animal model of osteoporosis, the ovariectomy-induced increases in bone resorption biomarkers such as pyridinoline and tartrate-resistant acid phosphatase were significantly reduced by E. papyrifera extract administration at 25.6 and 48.1%, respectively. Furthermore, the ovariectomy-induced bone loss in animal models of osteoporosis was significantly prevented by the administration of E. papyrifera in our study. Taking these observations into account, we suggest that E. papyrifera is an interesting candidate for further exploration as an anti-osteoporotic agent.

Cellulomonas aurantiaca sp. nov., isolated from a soil sample from a tangerine field.

A Gram-stain positive, facultatively aerobic, motile and rod-shaped bacterial strain, designated THG-SMD2.3T, was isolated from a soil sample collected in a tangerine field, Republic of Korea. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Cellulomonas and to be closely related to Cellulomonas fimi ATCC 484T (98.5%), Cellulomonas biazotea DSM 20112T (98.3%), Cellulomonas chitinilytica X.bu-bT (98.0%), Cellulomonas xylanilytica XIL11T (97.2%), Cellulomonas humilata ATCC 25174T (97.1%) and Cellulomonas composti TR7-06T (97.0%). The 16S rRNA gene sequence similarities with other current species of the genus Cellulomonas were in the range 95.4-96.6%. Catalase and oxidase tests were found to be positive. The DNA G+C content was determined to be 73.0 mol%. DNA-DNA hybridization values between strain THG-SMD2.3T and C. fimi ATCC 484T, C. biazotea DSM 20112T, C. chitinilytica X.bu-bT, C. xylanilytica XIL11T, C. humilata ATCC 25174T and C. composti TR7-06T were 58.1 ± 1.6%, 56.7 ± 0.8%, 30.3 ± 1.6%, 22.8 ± 1.6%, 19.9 ± 1.6%, and 13.5 ± 3.0%, respectively. Strain THG-SMD2.3T was also found to be able to grow at 20-42 °C, at 0-3% NaCl and at pH 5.5-10. The major fatty acids were identified as anteiso-C15:0, iso-C15:0, anteiso-C17:0 and iso-C14:0. The predominant menaquinone was identified as tetrahydrogenated menaquinones with nine isoprene units [MK-9(H4)]. The polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and two unidentified phospholipids. Based on these phenotypic, genotypic and phylogenetic characterisations strain THG-SMD2.3T (= KACC 19341T = CGMCC 1.16303T) is concluded to represent a novel species of the genus Cellulomonas, for which the name Cellulomonas aurantiaca sp. nov. is proposed.

Chitinophaga aurantiaca sp. nov., isolated from a soil sample from a tangerine field.

A Gram-stain-negative, facultatively anaerobic, non-motile and rod-shaped bacterial strain, designated THG-SD5.5T, was isolated from a soil sample collected in a tangerine field, Republic of Korea. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Chitinophaga and to be closely related to Chitinophaga ginsengihumi KACC 17604T (97.9%) and Chitinophaga rupis KACC 14521T (97.5%). The 16S rRNA gene sequence similarities with other species of the genus Chitinophaga were in the range 92.8-95.5%. Catalase test was positive. Oxidase test was negative. The DNA G + C content was determined to be 46.1 mol%. DNA-DNA hybridization values between strain THG-SD5.5T and C. ginsengihumi KACC 17604T and C. rupis KACC 14521T were 45.1% and 15.6%, respectively. Strain THG-SD5.5T was also found to be able to grow at 24-33 °C, at 0-5% NaCl and at pH 5.5-9.0. The major fatty acids were identified as anteiso-C15:0, C16:0, anteiso-C17:0 and C18:0. The dominant respiratory quinone was identified as menaquinone-7 (MK-7). The polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminolipid, two unidentified phospholipids and three unidentified lipids. Based on these phenotypic, genotypic and phylogenetic characterisations, strain THG-SD5.5T (= KACC 19338T = CGMCC 1.16304T) is concluded to represent a novel species of the genus Chitinophaga, for which the name Chitinophaga aurantiaca sp. nov. is proposed.

Glaciecola amylolytica sp. nov., an amylase-producing bacterium isolated from seawater.

A Gram-stain-negative, aerobic, non-motile and coccus-shaped bacterium (THG-3.7T) was isolated from seawater. Growth occurred at 10-30 °C (optimum 25 °C), at pH 6-8 (optimum 7) and in the presence of 1-8 % (w/v) NaCl (optimum 4 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-3.7T were identified as Paraglaciecola mesophila DSM 15026T (95.3 % similarity), Glaciecola pallidula DSM 14239T (95.2 %), Paraglaciecola aquimarina KCTC 32108T (95.1 %), Paraglaciecola arctica KACC 14537T (94.9 %), Glaciecola nitratireducens KCTC 12276T (94.7 %) and Paraglaciecola psychrophila CGMCC 1.6130T (94.7 %). 16S rRNA gene sequence similarities among strain THG-3.7T and other species were lower than 94.7 %. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified lipid and one unidentified aminolipid. The quinone system was composed of Q-8. The major fatty acids were C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain THG-3.7T was 47.9 mol%. On the basis of the data presented, strain THG-3.7T represents a novel species of the genus Glaciecola, for which the name Glaciecola amylolytica sp. nov. is proposed. The type strain is THG-3.7T (=KACC 19478T=CCTCC AB 2017258T).

Dietary enzyme-treated Hibiscus syriacus L. protects skin against chronic UVB-induced photoaging via enhancement of skin hydration and collagen synthesis.

Exposure of skin to UVB radiation is associated with skin thickening, erythema, deep wrinkles, and marked losses of elasticity, resilience, and hydration. To find effective anti-aging materials, scientists have studied not only natural nutritional sources, but also biotransformed metabolites. Although Hibiscus syriacus L., the national flower of Korea has been used extensively throughout history, it has not yet been examined for possible anti-aging effects. In this study, skin anti-aging effects of H. syriacus L. water extract (HSL) and enzyme-treated H. syriacus L. extract (ETH) were investigated in normal human dermal fibroblasts (NHDFs) in vitro and in hairless mice in vivo. In UVB-irradiated NHDFs, higher level of type I procollagen and lower levels of matrix metalloproteinase-1 (MMP-1), mitogen-activated protein kinases (MAPKs), and activator protein-1 (AP-1) expression were identified after treatment with HSL and ETH. In photoaged hairless mice, skin thickening and the density of collagen fibers and filaggrin improved after oral administration of HSL and ETH. ETH 1% significantly inhibited melanin content, erythema index (EI), transepidermal water loss (TEWL), stratum corneum (SC) hydration, and wrinkle formation. Palmitic acid and linoleic acid were more abundant in ETH than in HSL. Taken together, both HSL and ETH protect skin from UVB-induced premature photoaging, and enzymatic biotransformed products like ETH have potential for use as valuable functional foods.

Alveolar Bone Protective Effect of Hiziki Extracts on the Progression of Periodontitis.

The purpose of this study was to evaluate the effects of hiziki extract on alveolar bone loss, inflammation, and osteo-biomarker expression in hPDL cells (10, 50, 100 µg/ml final concentrations in culture medium) and on a ligature-induced periodontitis rat model (50, 100, 200 mg/kg with oral administration). Hiziki extract increased alkaline phosphatase activity and mineralized nodule formation in hPDL cell. In western blot analysis, hiziki extract resulted in increased expression of osteoblast markers, including transforming growth factor beta (TGF-ß), SMAD anchor for receptor activation (SARA) and runt-related transcription factor 2 (RUNX2) in hDPL cells. Additionally, expression of osteoclast markers and inflammatory cytokines was inhibited, which were receptor activator of NF-κB (RANK), RANK receptor (RANKL) and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1). Hiziki extract also prevented alveolar bone loss in a ligature-induced periodontitis rat model through reducing the distance between cementoenamel junction and alveolar bone crest (CBJ-ABC) and furcation involvement. These findings suggested that hiziki extract has prophylactic potential for the prevention of periodontitis through anti-inflammation and, anti-bone resorption effects and the inhibition of alveolar bone destruction.

Evaluation of in-vitro antimicrobial activity of Artemisia apiacea H. and Scutellaria baicalensis G. extracts.

PURPOSE: In traditional Korean medicine, Artemisia apiacea H. (ART) and Scutellaria baicalensis G. (SCU) are combined for the treatment of malaria and other malaria-like diseases. Because SCU is well-known as an antibacterial agent, the antimicrobial effect of a mixture of ART and SCU was investigated. METHODOLOGY: Plant samples were purchased from Kyungdong mart and extracted with 70 % ethanol. The in vitro antimicrobial activity of ART and SCU against pathogenic fungi (Aspergillus niger, Aspergillus oryzae, Candida albicans, Candida tropicalis and Candida glabrata), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) was evaluated using a broth microdilution assay, modified-disc diffusion and agar dilution methods with further CH2Cl2-fractionated ART, SCU and a mixture of ART/SCU (at a ratio of 3 : 5) (THAN-1). RESULTS: ART and SCU were effective against A. niger, C. albicans, B. subtilis and S. aureus. The range of minimum inhibitory concentration (MIC) values was 0.03125 to 4 mg ml-1 in the ART and SCU treatments. ART exhibited stronger activity than SCU. Interestingly, a 3 : 5 ratio mixture of ART and SCU (THAN-1) showed stronger antimicrobial activity than ART or SCU used individually. CONCLUSION: A treatment using a mixture of herbs such as THAN-1 would be useful in the suppression of the growth of pathogenic bacterial and fungal strains.

Enhancement of Protective Effects of Radix Scutellariae on UVB-induced Photo Damage in Human HaCaT Keratinocytes.

Radix Scutellariae (RS) has long been used in the treatment of inflammatory and allergic diseases. Its main flavonoids, baicalin (BG) and wogonoside (WG), can be hydrolyzed into their corresponding aglycones, baicalein (B) and wogonin (W). In this study, we developed a safe and effective method of transforming these glycosides using Peclyve PR. The transformation rate of BG and WG reached 98.5 and 98.1%, respectively, with 10% enzyme at 40 °C for 60 h. Furthermore, we compared the anti-photoaging activity of RS before and after enzyme treatment, as well as their respective main components, in UVB-irradiated HaCaT cells. Results found that enzyme-treated RS (ERS) appeared to be much better at preventing UVB-induced photoaging than RS. ERS significantly inhibited the upregulation of matrix metalloproteinase-1 and IL-6 caused by UVB radiation by inactivating the MAPK/AP-1 and NF-κB/IκB-α signaling pathways. ERS treatment also recovered UVB-induced reduction of procollagen type I by activating the TGF-ß/Smad pathway. In addition, ERS exhibited an excellent antioxidant activity, which could increase the expression of cytoprotective antioxidants such as HO-1 and NQ-O1, by facilitating Nrf2 nuclear transfer. These findings demonstrated that the photoprotective effects of RS were significantly improved by enzyme-modified biotransformation.

Deinococcus hibisci sp. nov., isolated from rhizosphere of Hibiscus syriacus L. (mugunghwa flower).

A Gram-stain-positive, pink-pigmented, coccus-shaped, strictly aerobic, non-motile bacterium, strain THG-AG1.5T, was isolated from rhizosphere of Hibiscus syriacus L. (Mugunghwa flower) located in Kyung Hee University, Yongin, Gyeonggi, Republic of Korea. The isolated strain grew optimally at 25-30 °C, at pH 6.0-7.5 and in the presence of additional 0-1.5 % (w/v) NaCl. Strain THG-AG1.5T exhibited tolerance to UV radiation (>1500 J m-2) and to gamma radiation (>12 kGy). Based on 16S rRNA gene sequence comparisons, strain THG-AG1.5T was closely related to Deinococcus daejeonensis MJ27T (98.03 %), Deinococcus radiotolerans C1T (97.61 %) and Deinococcus grandis DSM 3963T (97.32 %). The genomic DNA G+C content of strain THG-AG1.5T was 74.8 mol%. The DNA-DNA hybridization values between strain THG-AG1.5T and its closest phylogenetically neighbours were below 63.0 %. The peptidoglycan amino acids were alanine, valine, glutamic acid, glycine, ornithine, lysine and aspartic acid. Strain THG-AG1.5T contained ribose, mannose and glucose as whole-cell-wall sugars and menaquinone-8 (MK-8) as the only isoprenoid quinone. The major component in the polyamine pattern was spermidine. The major polar lipids of strain THG-AG1.5T were a phosphoglycolipid, six unidentified glycolipids and an unidentified aminophospholipid. The major fatty acids were identified as iso-C15 : 0, C15 : 1ω6c, C16 : 0, iso-C17 : 0, C17 : 0, C18 : 0 and summed feature 3. On the basis of our polyphasic taxonomy study, strain THG-AG1.5T represents a novel species within the genus Deinococcus, for which the name Deinococcushibisci sp. nov. is proposed. The type strain is THG-AG1.5T (=KACC 18850T=CCTCC AB 2016078T).

Eucalyptus globulus extract protects against UVB-induced photoaging by enhancing collagen synthesis via regulation of TGF-ß/Smad signals and attenuation of AP-1.

UV irradiation triggers the overproduction of matrix metalloproteinases and collagen degradation, which in turn causes increased pigmentation, dryness, and deep wrinkling of the skin. These chronic symptoms are collectively referred to as photoaging. Eucalyptus globulus is an evergreen tree that is widely used in cosmetics because of its antimicrobial activity. In this study, we investigated the protective effect of 50% ethanol extracts of Eucalyptus globulus on UV-induced photoaging in vitro and in vivo. Normal human dermal fibroblasts were treated with Eucalyptus globulus at concentrations ranging from 1 to 100 µg/mL after UVB or non-UVB irradiation. We found that Eucalyptus globulus suppressed the expression of MMPs and IL-6, but increased the expression of TGF-ß1 and procollagen type 1. In addition, Eucalyptus globulus inhibited activation of the AP-1 transcription factor, an inducer of MMPs. Eucalyptus globulus was also found to regulate TGF-ß/Smad signaling by reversing the activity of negative Smad regulators. Lastly, in vivo studies showed that topical application of Eucalyptus globulus on UVB-irradiated hairless mice reduced wrinkle formation and dryness by down-regulating MMP-1 and up-regulating expression of elastin, TGF-ß1, and procollagen type 1. Taken together, these data suggest that Eucalyptus globulus may be a useful agent in cosmetic products.

Flavobacterium limi sp. nov., isolated from forest mud.

A Gram-stain-negative, aerobic, non-motile, yellow and rod-shaped bacterial strain was isolated from forest mud located at Kyung Hee University, South Korea. Strain THG-AG6.4T grew at 10-35 °C, pH 6.0-9.5 and in the presence of 0-1.5 % (w/v) NaCl. Phylogenetic analysis, based on 16S rRNA gene sequencing, showed that strain THG-AG6.4T was most closely related to Flavobacterium gyeonganense HME 7524T (97.66 %), Flavobacterium defluvii EMB 117T (96.93 %) and Flavobacterium arsenitoxidans S2-3HT (96.80 %). The DNA G+C content of strain THG-AG6.4T was 30.2 mol%. The DNA-DNA relatedness values between strain THG-AG6.4T and its closest phylogenetic neighbour, F. gyeonganense HME 7524T, were below 61.0 %. The predominant quinone of strain THG-AG6.4T was MK-6. The major polar lipids were phosphatidylethanolamine, an unidentified phospholipid, five unidentified glycolipids, phosphatidylserine, an unidentified lipid, an unidentified aminophospholipid, two unidentified aminolipids and two unidentified aminoglycolipids. The major fatty acids were C16 : 0, C18 : 0 10-methyl, summed feature 3 and C18 : 1ω9c. The major polyamine was homospermidine. On the basis of the phenotypic, genotypic and phylogenetic characterization of strain THG-AG6.4T, it is concluded that the isolate represents a novel species of the genus Flavobacterium, for which the name Flavobacterium limi sp. nov. is proposed, with THG-AG6.4T as the type strain (=KACC 18851T=CGMCC 1.16060T).

Caulobacter hibisci sp. nov., isolated from rhizosphere of Hibiscus syriacus L. (Mugunghwa flower).

A Gram-stain-negative, smooth, bright yellow-pigmented, aerobic, catalase- and oxidase-positive and rod-shaped bacterial strain was isolated from rhizosphere of Hibiscus syriacus L. (Mugunghwa flower) located in Kyung Hee University, Yongin, Gyeonggi, South Korea. Cells were dimorphic, non-motile or non-stalked, and motile by means of peritrichous flagellum. The strain, named THG-AG3.4T, grew at 15-35 °C, at pH 6.5-9.0 and in the presence of 0-1.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain THG-AG3.4T was most closely related to Caulobacter segnis ATCC 21756T (98.64 % similarity), Caulobacter vibrioides CB51T (98.57 %) and Caulobacter henricii ATCC 15253T (97.41 %). The DNA G+C content of strain THG-AG3.4T was 64.0 mol%. In DNA-DNA hybridization, the DNA-DNA relatedness between strain THG-AG3.4T and its closest phylogenetic neighbour was below 55.0 %. The predominant isoprenoid quinone detected in strain THG-AG3.4T was ubiquinone-10 (Q-10). The major polar lipids were found to be an unidentified lipid, two unidentified phosphoglycolipids, five unidentified glycolipids, eight unidentified aminolipids and phosphatidylglycerol. The major fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). Thus, based on the report of the phenotypic, genotypic and phylogenetic characterization of strain THG-AG3.4T, it has been concluded that the isolate represents a novel species of the genus Caulobacter, for which the name Caulobacter hibisci sp. nov. is proposed. The type strain is THG-AG3.4T (=KACC 18849T=CCTCC AB 2016077T).

Microbacterium hibisci sp. nov., isolated from rhizosphere of mugunghwa (Hibiscus syriacus L.).

A Gram-stain-positive, aerobic, non-motile, short-rod shaped actinobacterium, designated THG-T2.14T, was isolated from soil sampled from the rhizosphere of mugunghwa. Growth occurred at 10-40 °C (optimum 30 °C), at pH 5.0-10.0 (optimum 7.0) and at 0-7.0 % NaCl (optimum 3.0 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.14T were identified as Microbacterium yannicii DSM 23203T (98.8 %), Microbacterium trichothecenolyticum DSM 8608T (98.8 %), Microbacterium arthrosphaerae DSM 22421T (98.7 %) and Microbacterium jejuense KACC 17124T (98.4 %). The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified lipid, two unidentified phospholipids and two unidentified phosphoglycolipids. The menaquinones were MK-12, and MK-13. The major polyamine was spermidine. The peptidoglycan contained ornithine, alanine, glycine, homoserine and glutamic acid. The diagnostic diamino acid was ornithine. The acyl type of the muramic acid was glycolyl. The whole-cell sugars were rhamnose, ribose, galactose, arabinose, xylose and glucose. The DNA G+C content of strain THG-T2.14T was 71.2 mol%. The DNA-DNA relatedness between strain THG-T2.14T and its closest reference strains were significantly lower than the threshold value of 70 %. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.14T represents a novel species of the genus Microbacterium, for which the name Microbacterium hibisci sp. nov. is proposed. The type strain is THG-T2.14T (=KACC 18931T=CCTCC AB 2016180T).

Altererythrobacter deserti sp. nov., isolated from desert soil.

A Gram-stain-negative, aerobic, short rod-shaped, non-motile bacterium (THG-S3T), was isolated from desert soil. Growth occurred at 15-35 °C (optimum 28 °C), at pH 5-10 (optimum 7) and at 0-4 % NaCl (optimum 1 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-S3T were identified as Altererythrobacter rigui KCTC 42620T (99.0 %), Altererythrobacter dongtanensis KCTC 22672T (97.1 %), Altererythrobacter xinjiangensis CCTCC AB 207166T (96.9 %), Altererythrobacter troitsensis KCTC 12303T (96.9 %). Levels of relatedness among strain THG-S3T and other Altererythrobacter species were lower than 96.0 %. DNA-DNA hybridization values between strain THG-S3T and A. rigui KCTC 42620T, A. dongtanensis KCTC 22672T, A. xinjiangensis CCTCC AB 207166T and A. troitsensis KCTC 12303T were 59.7 % (42.8 %, reciprocal analysis), 45.1 % (36.3 %), 34.7 % (25.1 %) and 15.1 % (12.3 %), respectively. The DNA G+C content of strain THG-S3T was 69 mol%. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and three unidentified lipids The quinone was ubiquinone-10. The major fatty acids were C16 : 0, C17 : 1 ω6c, C18 : 1 ω7c and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-S3T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter deserti sp. nov. is proposed. The type strain is THG-S3T (=KACC 19190T=CGMCC 1.15959T).