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result(s) for
"Kwon, O-Chul"
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Qualitative and quantitative analysis of flavonoids from 12 species of Korean mulberry leaves
2018
The total flavonoids in leaves of 12 varieties of Korean mulberry (Morus alba L.) were determined. Seventeen flavonoids were isolated and analyzed using ultra-performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC–DAD–QTOF/MS). To determine the flavonoid contents, HPLC analysis was performed on these 17 flavonoids. The total flavonoid contents of the 12 varieties of mulberry leaves ranged from 748.5 to 1297.9 mg, with the highest obtained from the Cheong Su variety (1297.9 ± 112.0 mg). Among the 17 flavonoids analyzed, quercetin 3-O-rutinoside (rutin) and quercetin 3-O-glucoside (isoquercitrin) had highest contents in the Cheong Su variety. Furthermore, the Dae Dang Sang variety gave the highest quercetin 3-O-rutinoside (rutin) content among the mulberry leaves investigated, at 425.5 ± 45.9 mg. Major flavonols from Dae Dang Sang were detected by UPLC–DAD–QTOF/MS. A total of 17 flavonoid compound peaks were identified in the analysis time range of 5–40 min, all of which were kaempferol and quercetin glycosides. Seven of the 17 compounds identified in mulberry leaves were unknown.
Journal Article
Effects of Ganodermanondiol, a New Melanogenesis Inhibitor from the Medicinal Mushroom Ganoderma lucidum
2016
Ganoderma lucidum, a species of the Basidiomycetes class, has been attracting international attention owing to its wide variety of biological activities and great potential as an ingredient in skin care cosmetics including “skin-whitening” products. However, there is little information available on its inhibitory effect against tyrosinase activity. Therefore, the objectives of this study were to investigate the chemical composition of G. lucidum and its inhibitory effects on melanogenesis. We isolated the active compound from G. lucidum using ethanol extraction and ethyl acetate fractionation. In addition, we assayed its inhibitory effects on tyrosinase activity and melanin biosynthesis in B16F10 melanoma cells. In this study, we identified a bioactive compound, ganodermanondiol, which inhibits the activity and expression of cellular tyrosinase and the expression of tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF), thereby decreasing melanin production. Furthermore, ganodermanondiol also affected the mitogen-activated protein kinase (MAPK) cascade and cyclic adenosine monophosphate (cAMP)-dependent signaling pathway, which are involved in the melanogenesis of B16F10 melanoma cells. The finding that ganodermanondiol from G. lucidum exerts an inhibitory effect on tyrosinase will contribute to the use of this mushroom in the preparation of skin care products in the future.
Journal Article
UPLC-DAD-QTOF/MS Analysis of Flavonoids from 12 Varieties of Korean Mulberry Fruit
by
Kim, Hyun-Bok
,
Kim, Yong-Soon
,
Sung, Gyoo-Byung
in
antioxidant activity
,
Antioxidants
,
Chemistry
2019
Mulberry (Morus alba L.) has been used in East Asia (Korea, China, and Japan) as a medicine because of its various pharmacological effects including the excellent antioxidant properties of its fruit. This study analyzed extracts from 12 varieties of Korean mulberry fruit for flavonoids using ultrahigh-performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS). Six quercetin derivatives were identified by mass spectrometry (MS) based on the [quercetin + H]+ ion (m/z 303), while four kaempferol derivatives were identified based on the [kaempferol + H]+ ion (m/z 287). Two new compounds (morkotin A and morkotin C, quercetin derivatives) were identified for the first time in mulberry fruit. The total flavonoid contents of the mulberry fruits ranged from 35.0 ± 2.3 mg/100 g DW in the Baek Ok Wang variety (white mulberry) to 119.9 ± 7.0 mg/100 g DW in the Dae Shim variety. This study has, for the first time, evaluated the flavonoid chromatographic profiles of 12 varieties of Korean mulberry fruits in a following quali-quantitative approach, which will contribute to improved utilization of these fruits as health foods.
Journal Article
SNP and SCAR Markers for Specific Discrimination of Antler-Shaped Ganoderma lucidum
by
Park, Young-Jin
,
Lee, Chang-Soo
,
Kwon, O-Chul
in
Amplification
,
Annealing
,
Deoxyribonucleic acid
2019
In this study we identified single nucleotide polymorphism (SNP) and sequence characteristic amplification region (SCAR) markers for specific identification of antler-shaped Ganoderma lucidum strains. When the partial mitochondrial SSU rDNA gene sequence of various antler- and kidney-shaped G. lucidum strains were analyzed and aligned, an SNP was found only in the antler-shaped G. lucidum strain at position 456 bp. In addition, this SNP of antler-shaped strains was digested by HinfI restriction enzyme. We further analyzed the polymorphism of various G. lucidum strains by random amplified polymorphic DNA (RAPD) analysis. In RAPD analysis, we isolated and sequenced a fragment, specific for antler-shaped G. lucidum strains. Based on this specific fragment sequence, two sets of specific primer pairs for antler-shaped G. lucidum strains were designed. PCR analysis revealed that two specific bands were observed only from antler-shaped strains. These two molecular markers will be helpful for identification of morphological characteristics of G. lucidum.
Journal Article
Anti-inflammatory activity of 3,5,6,7,3′,4′-hexamethoxyflavone via repression of the NF-κB and MAPK signaling pathways in LPS-stimulated RAW264.7 cells
by
Lee, Chang Soo
,
Kim, Se-Hee
,
Nam, Jae Young
in
Animals
,
anti-inflammatory
,
Anti-inflammatory agents
2020
Citrus peel has been used as a Traditional medicine in Asia to treat coughs, asthma and bronchial disorders. Therefore, the anti-inflammatory effects of 3,5,6,7,3′,4′-hexamethoxyflavone (quercetogetin, QUE) isolated from Citrus unshiu peel were investigated in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. The results showed that QUE repressed the production of prostaglandin E2 and nitric oxide by suppressing LPS-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase. It also suppressed the production of interleukin (IL)-6, IL-1β, and tumor necrosis factor-α cytokines, and decreased the nuclear translocation of NF-κB by interrupting the phosphorylation of NF-κB inhibitor α in macrophage cells. Based on the finding that QUE inhibited the phosphorylation of ERK protein expression in LPS-induced RAW264.7 cells, it was confirmed that inhibition of inflammatory responses by QUE was mediated via the ERK pathway. Therefore, this study suggests that QUE has strong anti-inflammatory effects, making it a promising compound for use as a therapeutic agent in treating inflammatory lung diseases, such as emphysema.
Journal Article
Next-Generation Sequencing-Based Genome-Wide Mutation Analysis of L-Lysine-Producing Corynebacterium glutamicum ATCC 21300 Strain
by
Son, E.S., Konkuk University, Chungju, Republic of Korea
,
Han, W.R.J.R., Konkuk University, Chungju, Republic of Korea
,
Kwon, O.C., Konkuk University, Chungju, Republic of Korea
in
Amino acids
,
Base Sequence
,
Biomedical and Life Sciences
2012
In order to identify single nucleotide polymorphism and insertion/deletion mutations, we performed whole-genome re-sequencing of the enhanced L-lysine-producing Corynebacterium glutamicum ATCC 21300 strain. In total, 142 single nucleotide polymorphisms and 477 insertion/deletion mutations were identified in the ATCC 21300 strain when compared to 3,434 predicted genes of the wild-type C. glutamicum ATCC 13032 strain. Among them, 110 transitions and 29 transversions of single nucleotide polymorphisms were found from genes of the ATCC 21300 strain. In addition, 11 genes, involved in the L-lysine biosynthetic pathway and central carbohydrate metabolism, contained mutations including single nucleotide polymorphisms and insertions/deletions. Interestingly, RT-PCR analysis of these 11 genes indicated that they were normally expressed in the ATCC 21300 strain. This information of genome-wide gene-associated variations will be useful for genome breeding of C. glutamicum in order to develop an industrial amino acid-producing strain with minimal mutation.
Journal Article
Anti-inflammatory activity of 3,5,6,7,3',4'-hexamethoxyflavone via repression of the NF-kappaB and MAPK signaling pathways in LPS-stimulated RAW264.7 cells
2020
Citrus peel has been used as a Traditional medicine in Asia to treat coughs, asthma and bronchial disorders. Therefore, the anti-inflammatory effects of 3,5,6,7,3',4'-hexamethoxyflavone (quercetogetin, QUE) isolated from Citrus unshiu peel were investigated in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. The results showed that QUE repressed the production of prostaglandin E2 and nitric oxide by suppressing LPS-induced expression of cyclooxygenase-2 and inducible nitric oxide synthase. It also suppressed the production of interleukin (IL)-6, IL-1[beta], and tumor necrosis factor-[alpha] cytokines, and decreased the nuclear translocation of NF-[kappa]B by interrupting the phosphorylation of NF-[kappa]B inhibitor a in macrophage cells. Based on the finding that QUE inhibited the phosphorylation of ERK protein expression in LPS-induced RAW264.7 cells, it was confirmed that inhibition of inflammatory responses by QUE was mediated via the ERK pathway. Therefore, this study suggests that QUE has strong anti-inflammatory effects, making it a promising compound for use as a therapeutic agent in treating inflammatory lung diseases, such as emphysema.
Journal Article
EFFECTS OF FISCAL AND MONETARY POLICIES ON CAPITAL FORMATION: A DYNAMIC ANALYSIS
1984
Effects of fiscal and monetary policies on private capital formation have been studied extensively (e.g., Feldstein (1980), Henderson and Sargent (1973) and Tobin and Buiter (1982)). However, these studies are restricted to the analysis within a static framework in nature. They assume that firms either maximize profits in a firm's static problems or they assume firms maximize the present value of its future net cash flows without introducing adjustment costs in a perfect capital market. Because of the assumption that the firm adjusts instantaneously its stock of capital to the desired level, together with the one of no adjustment cost, they are always in steady state, i.e., they apply myopic rule. This assumption of instantaneous adjustment of capital is not realistic in a macroeconomic model because the amount of investment is restricted by the society's amount of savings. In this thesis, dynamic behavior of firms with adjustment cost of investment is studied and the investment schedule is derived as a function of its shadow price (Tobin's marginal \"q\") in real terms, which in turn changes over time depending on the rates of interest, depreciation and inflation, and the marginal product of capital. We have formulated two macroeconomic models. The first one is without wealth effect and the second one is with wealth effect which operates through goods market and asset market. A dichotomy between fiscal deficits and monetary policy is found in the first model. An increase in the fiscal deficits unambiguously decreases the shadow price of investment and the capital stock, and increases real interest rate both in the long run and in the short run. On the other hand, money is neutral in the first model without formulating a rational expectation hypothesis. In the second model an increase in the fiscal deficits unambiguously decreases the capital accumulation and the shadow price of investment whereas an increase in the growth rate of money unambiguously increases the capital accumulation and the shadow price of investment in the long run. Money is no longer neutral in the second model. All the results about effects of fiscal and monetary policies on capital accumulation, rates of interest, inflation and real money supply differ immensely from those of a static analysis.
Dissertation
Characterization of alcohol dehydrogenase 1 of the thermotolerant methylotrophic yeast Hansenula polymorpha
by
Seo, Jeong-Woo
,
Kang, Hyun Ah
,
Rhee, Sang Ki
in
Acetaldehyde
,
Acetaldehyde - metabolism
,
Alcohol
2010
The thermotolerant methylotrophic yeast
Hansenula polymorpha
has recently been gaining interest as a promising host for bioethanol production due to its ability to ferment xylose, glucose, and cellobiose at elevated temperatures up to 48 °C. In this study, we identified and characterized alcohol dehydrogenase 1 of
H. polymorpha
(HpADH1). HpADH1 seems to be a cytoplasmic protein since no N-terminal mitochondrial targeting extension was detected. Compared to the ADHs of other yeasts, recombinant HpADH1 overexpressed in
Escherichia coli
exhibited much higher catalytic efficiency for ethanol oxidation along with similar levels of acetaldehyde reduction. HpADH1 showed broad substrate specificity for alcohol oxidation but had an apparent preference for medium chain length alcohols. Both ADH isozyme pattern analysis and ADH activity assay indicated that ADH1 is the major ADH in
H. polymorpha
DL-1. Moreover, an
HpADH1
-deleted mutant strain produced less ethanol in glucose or glycerol media compared to wild-type. Interestingly, when the
ADH1
mutant was complemented with an
HpADH1
expression cassette, the resulting strain produced significantly increased amounts of ethanol compared to wild-type, up to 36.7 g l
−1
. Taken together, our results suggest that optimization of ADH1 expression would be an ideal method for developing
H. polymorpha
into an efficient bioethanol production strain.
Journal Article
Enhancement of heterologous production of eicosapentaenoic acid in Escherichia coli by substitution of promoter sequences within the biosynthesis gene cluster
by
Seo, Jeong-Woo
,
Kwon, Ohsuk
,
Seo, Pil-Soo
in
Applied Microbiology
,
Biochemistry
,
Bioengineering
2008
To enhance the heterologous production of eicosapentaenoic acid (EPA) in Escherichia coli, the EPA biosynthesis gene cluster from Shewanella oneidensis MR-1 was cloned under the lacZ promoter on a high-copy number plasmid, pBluescript SK(+). The production of EPA was remarkably enhanced yielding levels of up to 7.5% of the total fatty acid content in the recombinant E. coli strain by induction with IPTG, whereas the stimulation of EPA production was abolished by adding glucose into the culture medium, probably due to glucose repression acting on the promoter activity.
Journal Article