• YAKHAK HOEJI
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• v.50 no.6
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• pp.345-350
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• 2006

The pharmacological properties of ginseng are mainly attributed to ginsenosides, the active constituents that are found in the extracts of different species of ginseng. Lately; the studies on ginsenosides are mainly focused on IH-901, a major intestinal bacterial metabolite of ginsenosides. In this study; we examined the anti-diabetic activity of IH-901 in C57BU61 db/db mice model. IH-901 was administrated orally at a dose of 20 mg/kg for 5 weeks. During the experimental period, body weight and blood glucose levels were measured every week. After 5 weeks, db/db mice were sacrificed and diabetic parameters were analyzed. IH-901 treated group showed a significant decrease in fasting blood glucose levels (from 10.5 mM to 9.4 mM), insulin resistance index (from 163.6 to 100.2) and triglyceride levels (from 115.3 to 70.1) compared to the diabetic control. In Pancreatic islets morphology; IH-901 treated group revealed much less infltrated mononuclear cells, indicating that IH-901 recovered ${\beta}$-cell damage due to hyperglycemia. In addition, IH-901 upregulated expressions of glucose transporter 4 (GLUT4) and PPAR-${\gamma}$ in skeletal muscle and adipose tissue, respectively. Taken together IH-901might be a potential anti-hyperglycemic agent with insulin sensitizing effect.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.853-863
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• 2021

Objective : Biodegradable poly-L-lactic acid (PLLA) with a highly biocompatible surface via tantalum (Ta) ion implantation can be an innovative solution for the problems associated with current biodegradable stents. The purpose of this study is to develop a Taimplanted PLLA stent for clinical use and to investigate its biological performance capabilities. Methods : A series of in vitro and in vivo tests were used to assess the biological performance of bare and Ta-implanted PLLA stents. The re-endothelialization ability and thrombogenicity were examined through in vitro endothelial cell and platelet adhesion tests. An in vivo swine model was used to evaluate the effects of Ta ion implantation on subacute restenosis and thrombosis. Angiographic and histologic evaluations were conducted at one, two and three months post-treatment. Results : The Ta-implanted PLLA stent was successfully fabricated, exhibiting a smooth surface morphology and modified layer integration. After Ta ion implantation, the surface properties were more favorable for rapid endothelialization and for less platelet attachment compared to the bare PLLA stent. In an in vivo animal test, follow-up angiography showed no evidence of in-stent stenosis in either group. In a microscopic histologic examination, luminal thrombus formation was significantly suppressed in the Ta-implanted PLLA stent group according to the 2-month follow-up assessment (21.2% vs. 63.9%, p=0.005). Cells positive for CD 68, a marker for the monocyte lineage, were less frequently identified around the Ta-implanted PLLA stent in the 1-month follow-up assessments. Conclusion : The use of a Ta-implanted PLLA stent appears to promote re-endothelialization and anti-thrombogenicity.

• Anatomy and Cell Biology
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• v.51 no.4
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• pp.266-273
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• 2018

The ganglion cardiacum or juxtaductal body is situated along the left recurrent laryngeal nerve in the aortic window and is an extremely large component of the cardiac nerve plexus. This study was performed to describe the morphologies of the ganglion cardiacum or juxtaductal body in human fetuses and to compare characteristics with intracardiac ganglion. Ganglia were immunostained in specimens from five fetuses of gestational age 12-16 weeks and seven fetuses of gestational age 28-34 weeks. Many ganglion cells in the ganglia were positive for tyrosine hydroxylase (TH; sympathetic nerve marker) and chromogranin A, while a few neurons were positive for neuronal nitric oxide synthase (NOS; parasympathetic nerve marker) or calretinin. Another ganglion at the base of the ascending aorta carried almost the same neuronal populations, whereas a ganglion along the left common cardinal vein contained neurons positive for chromogranin A and NOS but no or few TH-positive neurons, suggesting a site-dependent difference in composite neurons. Mixtures of sympathetic and parasympathetic neurons within a single ganglion are consistent with the morphology of the cranial base and pelvic ganglia. Most of the intracardiac neurons are likely to have a non-adrenergic non-cholinergic phenotype, whereas fewer neurons have a dual cholinergic/noradrenergic phenotype. However, there was no evidence showing that chromogranin A- and/or calretinin-positive cardiac neurons corresponded to these specific phenotypes. The present study suggested that the ganglion cardiacum was composed of a mixture of sympathetic and parasympathetic neurons, which were characterized the site-dependent differences in and near the heart.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.39-45
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• 2019

In 2017, as a study to discover indigenous prokaryotic species in Korea, a total of 6 bacterial strains assigned to the genus Pseudomonas were isolated from soil. From the high 16S rRNA gene sequence similarity (${\geq}99.5%$) and phylogenetic analysis with closely related species, the isolated strains were identified as independent Pseudomonas species which were unrecorded in Korea. The six Pseudomonas species were Pseudomonas mandelii, P. canadensis, P. thivervalensis, P. jessenii, P. lurida, and P. brenneri. Gram reaction, culture conditions, colony and cell morphology, basic physiological and biochemical characteristics are described in the species description section.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.241-248
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• 2019

Objective: To isolate and identify new methanogens from the rumen of Holstein steers in Korea. Methods: Representative rumen contents were obtained from three ruminally cannulated Holstein steers ($793{\pm}8kg$). Pre-reduced media were used for the growth and isolation of methanogens. Optimum growth temperature, pH, and sodium chloride (NaCl) concentration as well as substrate utilization and antibiotic tolerance were investigated to determine the physiological characteristics of the isolated strain. Furthermore, the isolate was microscopically studied for its morphology. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification. Results: One strain designated as KOR-2 was isolated and found to be a non-motile irregular coccus with a diameter of 0.2 to $0.5{\mu}m$. KOR-2 utilized $H_2+CO_2$ and formate but was unable to metabolize acetate, methanol, trimethylamine, 2-propanol, and isobutanol for growth and methane production. The optimum temperature and pH for the growth of KOR-2 were $38^{\circ}C$ and 6.8 to 7.0, respectively, while the optimum NaCl concentration essential for KOR-2 growth was 1.0% (w/v). KOR-2 tolerated ampicillin, penicillin G, kanamycin, spectromycin, and tetracycline. In contrast, the cell growth was inhibited by chloramphenicol. Phylogenetic analysis of 16S rRNA and mcrA genes revealed the relatedness between KOR-2 and Methanoculleus bourgensis. Conclusion: Based on the physiological and phylogenetic characteristics, KOR-2 was thought to be a new strain within the genus Methanoculleus and named Methanoculleus bourgensis KOR-2.

• Journal of Species Research
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• v.8 no.3
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• pp.249-258
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• 2019

Owing to a distinct environmental regime and anthropogenic effects, freshwater bacterial communities of urban streams are considered to be different from those of large freshwater lakes and rivers. To obtain unrecorded, freshwater bacterial species in Korea, water and sediment samples were collected from various urban streams of the Han River watershed in 2018. After plating the freshwater samples on R2A agar, approximately 1000 bacterial strains were isolated from the samples as single colonies and identified using 16S rRNA gene sequence analyses. A total of 26 strains, with >98.7% 16S rRNA gene sequence similarity with validly published bacterial species but not reported in Korea, were determined to be unrecorded bacterial species in Korea. The unrecorded bacterial strains were phylogenetically diverse and belonged to four phyla, six classes, 12 orders, 16 families, and 21 genera. At the generic level, the unreported species were assigned to Nocardioides, Streptomyces, Microbacterium, Kitasatospora, Herbiconiux, Corynebacterium, and Microbacterium of the class Actinobacteria; Paenibacillus and Bacillus of the class Bacilli; Caulobacter, Methylobacterium, Novosphingobium, and Porphyrobacter of the class Alphaproteobacteria; Aquabacterium, Comamonas, Hydrogenophaga, Laribacter, Rivicola, Polynucleobacter, and Vogesella of the class Betaproteobacteria; Arcobacter of the class Epsilonproteobacteria; and Flavobacterium of the class Flavobacteriia. The details of the 26 unreported species, including Gram reaction, colony and cell morphology, biochemical properties, and phylogenetic position are also provided in the strain descriptions.

• Journal of Species Research
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• v.8 no.2
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• pp.161-175
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• 2019

During a comprehensive investigation of indigenous prokaryotic species in Korea, a total of 46 bacterial strains assigned to the classes Alphaproteobacteria, Betaproteobacteria, Deltaproteobacteria, and Epsilonproteobacteria were isolated from a diversity of habitats including freshwater, seawater, brackish water, ginseng soil, plant roots, natural caves, and tidal flats. Based on their high 16S rRNA gene sequence similarities (>98.7%) and formation of strongly-supported phylogenetic clades with the closest type species, each strain was assigned to an independent, predefined bacterial species. Since there were no published or official reports regarding the isolation of these 46 species in Korea, here we report them as new species to Korea: 34 species in 14 families in the five orders of Alphaproteobacteria, 10 species in five families in the three orders of Betaproteobacteria, one species of Deltaproteobacteria and one species of Epsilonproteobacteria. Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs are described in the species description section.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.696-703
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• 2019

Cronobacter sakazakii is an opportunistic pathogen causing serious infections in neonates. In this study, a bacteriophage ${\Phi}CS01$, which infects C. sakazakii, was isolated from swine feces and its morphology, growth parameters, and genomic analysis were investigated. Transmission electron microscopy revealed that ${\Phi}CS01$ has a spherical head and is 65.74 nm in diameter with a 98.75 nm contracted tail, suggesting that it belongs to the family Myoviridae. The major viral proteins are approximately 71 kDa and 64 kDa in size. The latent period of ${\Phi}CS01$ was shown to be 60 min, and the burst size was 90.7 pfu (plaque-forming units)/infected cell. Bacteriophage ${\Phi}CS01$ was stable at $4-60^{\circ}C$ for 1 h and lost infectivity after 1 h of heating at $70^{\circ}C$. Infectivity remained unaffected at pH 4-9 for 2 h, while the bacteriophage was inactivated at pH <3 or >10. The double-stranded ${\Phi}CS01$ DNA genome consists of 48,195 base pairs, with 75 predicted open reading frames. Phylogenetic analysis is closely related to that of the previously reported C. sakazakii phage ESP2949-1. The newly isolated ${\Phi}CS01$ shows infectivity in the host bacterium C. sakazakii, indicating that it may be a promising alternative to antibacterial agents for the removal of C. sakazakii from powdered infant formulas.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.305-311
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• 2018

Gonadotropin releasing hormone (GnRH) centrally plays a role in control of the hypothalamic-pituitary-gonadal axis-related hormone secretions in the reproductive neuroendocrine system. In addition, hormone receptors like luteinizing hormone receptor (LHR) are important element for hormones to take effect in target organ. However, ageing-dependent changes in terms of the distribution of GnRH neurons in the brain and LHR expression in the acyclic ovary have not been fully understood yet. Therefore, we comparatively investigated those ageing-dependent changes using young (1-5 months), middle (11-14 months) and old (21-27 months) aged female mice. Whereas a number of GnRH positive fibers and neurons with monopolar or bipolar morphology were abundantly observed in the brain of the young and middle aged mice, a few GnRH positive neurons with multiple dendrites were observed in the old aged mice. In addition, acyclic ovary without repeated development and degeneration of the follicles was shown in the old aged mice than others. LHR expression was localized in theca cells, granulosa cell, corpora lutea and atretic follicle in the ovaries from young and middle aged mice, in contrast, old aged mice had few positive LHR expression on the follicles due to acyclic ovary. However, the whole protein level of LHR was higher in the ovary of old aged mice than others. These results are expected to be used as an important basis on the relationship between GnRH and LHR in old aged animals as well as in further research for reproduction failure.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.233-240
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• 2021

For the production of neodymium-doped zinc sulfide thin films in various amounts, zinc sulfide and neodymium were simultaneously deposited using an RF magnetron sputtering equipment to form a thin films, and rapid thermal annealing was performed at 400℃ for 30 minutes as a post-treatment process. The structure, shape, and optical properties of ZnS thin films having various neodymium doping contents (0.35at.%, 1.31at.%, 1.82at.% and 1.90at.%) were studied. The X-ray diffraction pattern was grown to a (111) cubic structure in all thin films. The surface and structural morphology of the thin films due to the neodymium doping content was explained through SEM and AFM images. Only elements of Zn, S, and Nd that do not contain other impurities were identified through EDAX. The transmittance and band gap of the prepared thin films were confirmed using the UV-vis spectrum.