• Journal of Microbiology
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• v.44 no.6
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• pp.600-606
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• 2006

Spore forming actinobacteria (sporoactinobacteria) isolated from soils with an acidic pH in Pinus thunbergii forests and coal mine waste were subjected to taxonomic characterization. For the isolation of acidophilic actinobacteria, acidified starch casein agar (pH adjusted to 4-5) was used. The numbers of actinobacteria growing in acidic media were between $3.2{\times}10^4$ and $8.0{\times}10^6$ CFU/g soil. Forty three acidophilic actinobacterial strains were isolated and their 16S rDNA sequences were determined. The isolates were divided into eight distinctive phylogenetic clusters within the variation encompassed by the family Streptomycetaceae. Four clusters among them were assigned to the genus Streptacidiphilus, whereas the remaining four were assigned to Streptomyces. The clusters belonging to either Streptomyces or Streptacidiphilus did not form a monophyletic clade. The growth pH profiles indicated that the representative isolates grew best between pH 5 and 6. It is evident from this study that acidity has played a critical role in the differentiation of the family Streptomycetaceae, and also that different mechanisms might have resulted in the evolution of two groups, Streptacidiphilus (strict acidophiles) and neutrotolerant acidophilic Streptomyces. The effect of geographic separation was clearly seen among the Streptacidiphilus isolates, which may be a key factor in speciation of the genus.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.86-90
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• 2003

A flat conversion loss in microwave mixer is hard to achieve if integrating with an image rejection filter(IRF). This is due to the change of termination condition with respect to the LO and IF frequency at RF port where the filter has 50 ohm termination property only in the RF band. This paper describes a flatness maintenance in the down mixer concerning a diode matching condition as well as an electrical length of embedding line at RF port. The implemented single balance diode mixer is suitable for a 23 ㎓ European Terrestrial Radio. RF, LO and fixed IF frequency chosen in this paper are 21.2∼22.4 ㎓, 22.4∼23.6 ㎓ and 1.2 ㎓, respectively. The measured results show a conversion loss of 8.5 ㏈, flatness of 1.2 ㏈ p-p, input P1㏈ of 7㏈m, IIP3 of 15.42 ㏈m with nominal LO power level of 10㏈m. The return loss of RF and LO port are less than - 15 ㏈ and - 12 ㏈, respectively and IF port is less than - 6 ㏈. LO/RF and LO/IF isolation are 18 ㏈ and 50 ㏈, respectively. This approach would be a helpful reference for designing up/down converter possessing a filtering element.

• Journal of Life Science
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• v.10 no.1
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• pp.14-19
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• 2000

Variation at 25 allozyme loci in Korean wateralder (Alnus hirsuta Rupr.) from nine distinct populations was measured to estimate the amount and pattern of genetic diversity and population structure. The mean genetic diversity within population was 0.166. Korean alder populations have slightly high levels of genetic diversity compared to those present in associated temperature-zone species and two Canadian alder species. Among population s genetic differentiation accounted for an significant 9% of the total variation. High gene flow(Nm=2.63) was observed. Analysis of fixation indices, calculated for all polymorphic loci in each population, showed a substantial deficiency of heterozygotes relative to Hardy-Weinberg expectations. The mean GST value A. hirsuta in Korea (GST = 0.087) is similar to those of A. rogosa in Canada (GST = 0.052). These low values of GST in two countries. reflecting little spatial genetic differentiation, may indicate extensive gene flow (via pollen and/or seeds) and/or recent colonization. These factors reduce the effect of geographic isolation of breeding and the chance for genetic divergence. A pattern of increasing is observed with increasing rainfall per year. Regression analysis indicates that 54% (F = 4.67) of the variability observed can be explained by this relationship.

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.283-289
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• 2015

The half-dried leaves of Stewartia. pseudocamellia were extracted with hot water (SPE) and partitioned with n-hexane (SPEH), dichloromethane (SPED), and ethyl acetate (SPEE) successively. SPE and SPEE showed significant inhibitory effects against melanogenesis and tyrosinase activities. By bioassay-guided isolation, ten phenolic compounds were isolated by column chromatography from SPEE. The whitening effect of the isolated compounds from SPEE were tested for the inhibitory activities against melanogenesis using B16 melanoma cells, in vitro inhibition of tyrosinase, and L-3,4-dihydorxy-indole-2-carboxylic acid (L-DOPA) auto-oxidation assay. A cytotoxic activity assay was done to examine the cellular toxicity in Raw 264.7 macrophage cells. Of the compounds isolated, gallic acid and quercetin revealed significant inhibitory activities against melanogenesis compared to arbutin. In particular, quercetin exhibited similar inhibitory activities against tyrosinase and L-DOPA oxidation without cytotoxicity. These results suggested that SPE could be used as a potential source of natural skin-whitening material in cosmetics as well as in food products.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.3
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• pp.792-796
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• 2004

In the courses of in vitro screening for the antioxidant effect of the various extracts from medicinal plants, n-BuOH soluble extract of the seeds of Xanthium strumarium was found to exhibit distinctive antioxidant activity. Further purifications of this extract as guided by in vitro antioxidant assay afforded caffeic acid and 3,5-di-O-caffeoyl quinic acid, which scavenged 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical in a dose-dependent manner of which IC50 values were 23.4 μg/ml (132.9 μM) and 29.8 μg/ml (57.9 μM), respectively.

• BMB Reports
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• v.48 no.5
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• pp.295-300
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• 2015

Stress and its related hormones epinephrine (E) and norepinephrine (NE) play a crucial role in tumor progression. Macrophages in the tumor microenvironment (TME) polarized to M2 is also a vital pathway for tumor deterioration. Here, we explore the underlying role of macrophages in the effect of stress and E promoting breast cancer growth. It was found that the weight and volume of tumor in tumor bearing mice were increased, and dramatically accompanied with the rising E level after chronic stress using social isolation. What is most noteworthy, the number of M2 macrophages inside tumor was up-regulated with it. The effects of E treatment appear to be directly related to the change of M2 phenotype is reproduced in vitro. Moreover, E receptor $ADR{\beta}2$ involved in E promoting M2 polarization was comprehended simultaneously. Our results imply psychological stress is influential on specific immune system, more essential for the comprehensive treatment against tumors. [BMB Reports 2015; 48(5): 295-300]

• Korean Journal of Veterinary Research
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• v.31 no.2
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• pp.195-199
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• 1991

Infectious pancreatic necrosis(IPN) virus was known as a causative agent of newly recognized viral disease of young rainbow trout characterized by highly contagious, high mortality and necrosis of pancreas. Several strains of IPN viruses were recovered from young rainbow trout that have been shown a typical cinical sign of infectious pancreatic necrosis disease. The field isolate produced cytopathic effect, and multiplied up to $10^{6.0}$ to $10^{6.5}$ $TCID_{50}/0.1ml$ in BT cell culture. In the indirect immunofluorescent assay with trout anti-IPN virus IgG and goat anti-trout IgG FITC conjugate, these isolates were proved to be a IPN virus that were closely related with VR277 strain of IPN virus antigenically.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.255-263
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• 2016

Antimicrobial properties of Licorice(Glycyrrhizae radix L.) against food spoilage microorganism, Bacillus subtilis KCTC 1021 was investigated. Antibacterial activity of the essential oil was as equivalent as Potassium metabisulfite and myconazole. The licorice extracts was fractionated to hexane, chloroform, ethyl acetate, butanol and water fraction. Chloroform fraction showed the highest inhibitory effect on the Bacillus subtilis KCTC 1021. Chloroform fraction was further fractionated by silica gel column chromatography and thin layer chromatography(TLC). The antibacterial compound was isolated from their fractions and its chemical structures was identified as (R)-glabridin by ESI-MS, $^1H$-NMR and $^{13}C$-NMR.

• Journal of Microbiology and Biotechnology
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• v.4 no.2
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• pp.126-133
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• 1994

A Pseudomonas putida strain able to accumulate high amount of polyesters of medium-chain-length 3-hydroxyalkanoic acids ($PHA_{MCL)$) was isolated from soil in a landfill site using an enrichment technique. Culture condition of the isolated strain for polyester production in a one-step culture was optimized in a mineral-salts medium against pH and concentrations of ammonium sulfate, carbon source(e.g., octanoate), and phosphate. The optimal values for maximal cell growth and PHA accumulation were: pH; 7$\sim$8, $(NH_4)_2SO_4$; 8 mM, octanoate; 40 mM. The optimum temperature was in the range of $20\sim30^{\circ}C$, which was rather broader than in other bacteria. Cell growth was strongly inhibited by the phosphate limitation to less than 1 mM. An increase of phosphate concentration above 1 mM showed little effect on cell growth and polyester accumulation. When the strain was grown on octanoate under this optimized condition it produced 3.4 g dry biomass per liter and yielded 1.7 g PHA per liter amounting to 53 wt% of dry cells. The monomer units composing the polyester synthesized from octanoate were 3-hydroxyoctanoate (3HO), 3-hydroxycaproate (3HC), and 3-hydroxybutyrate (3HB) (85:13:2, mole ratio). Other low linear $C_3\simC_{10}$ monocarboxylic acids were also tested for polyester production.

• Korean Journal of Veterinary Service
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• v.19 no.3
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• pp.213-219
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• 1996

Seventy-nine strains of Enterobacteriaceae isolated from 117 slaughtered pigs (bile, urine, small intestine, cecum and rectum) in 1995 were examined for biotypes and susceptibility to 19 antibiotics with MicroScan WalkAway 40/96. The obtained results were as follows : 1. Among the twenty-two species isolated from the samples, Proteus mirabilis, E. coli and Enterobacter cloacae were commonly encountered. 2. The distribution frequency of isolates from cecum, small intestine, rectum, bile, and urine was 31(38.8%), 25(31.3%), 18(22.8%), 3(3.7% ), and 2(2.5% ), respectively. 3. A majority of isolates were sensitive to 16 antibiotics, singly or in combination. And these isolates were commonly susceptible to various antibiotics such as Cp, Ts, Azt, Caz, To, Gm, Cfz, Crm, Am and Cfx, in order. Whereas the Salmonella spp was susceptible to Cf, Ti and Pi, and Proteus mirabilis to Imp, Tim, Cft and Cz. Meanwhile, no effect was found to Cf, Ak and Cax. 4. Among the antibiotic resistant strains, a total of 17 reistant patterns was noted End of these Ak Tim 45(57.0%), Ak Am Cf Cfx Cfz Tim 8(10.1%) and Ak Ti Tim 6(7.6% ) were frequently encountered.