• Biomolecules & Therapeutics
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• v.31 no.6
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• pp.648-654
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• 2023

Oxidative stress-induced melanocyte apoptosis is linked to the immune system and plays a critical role in the pathogenesis of vitiligo. Aquaporin-3 (AQP3), which is downregulated in vitiligo keratinocytes, regulates intracellular H₂O₂ accumulation. However, the role of AQP3 in oxidative stress is uncertain in vitiligo. This study investigated the effect of downregulated AQP3 on oxidative stress in vitiligo using lesional and non-lesional skin specimen sets from vitiligo patients and primary cultured adult normal human epidermal keratinocytes, with or without downregulation and overexpression of AQP3 in the presence or absence of H₂O₂ treatment. The levels of nuclear factor E2-related factor 2 (NRF2) and/or its main target, NAD(P)H quinone dehydrogenase 1 (NQO-1), were lower in the lesional keratinocytes and cultured keratinocytes with AQP3 knockdown, but were increased in keratinocytes upon AQP3 overexpression. Ratios of NRF2 nuclear translocation and NQO-1 expression levels were further reduced in AQP3-knockdown keratinocytes following H₂O₂ treatment. The conditioned media from AQP3-knockdown keratinocytes treated with H₂O₂ contained higher concentrations of reactive oxygen species (ROS). Moreover, the number of viable melanocytes was reduced when the conditioned media were added to the culture media. Overall, AQP3 downregulation in the keratinocytes of patients with vitiligo can induce oxidative stress in neighboring melanocytes, leading to melanocyte death.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.396-404
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• 2011

An investigation on the removals of PAH-quinone compounds, which are commonly produced from the biological and/or chemical treatments of PAH-contaminated soils, from the aqueous phase via birnessite (${\delta}-MnO_2$)-mediated oxidative transformation is described. It was demonstrated that acenaphthenequinone (APQ), p-PAH quinone can be removed via birnessite-mediated oxidative-coupling reactions, and anthraquinone (AQ) and 1,4-naphthoquinone (1,4-NPQ), o-PAH quinones were efficiently removed by birnessite-mediated cross-coupling reactions in the presence of catechol (CAT) as a reactive mediator. The removals of PAH-quinone compounds followed pseudo-first-order reactions, and the rate constant (k, $hr^{-1}$) for the removals of 1,4-NPQ under the experiment conditions (1,4-NPQ = 10 mg/L, CAT = 50 mg/L, ${\delta}-MnO_2$ = 1.0 g/L, pH 5, Reaction time = 6~96 hr) was 0.0426, which was about 4 times lower than that of APQ (0.173). With the observed pseudo-first order rate constants with respect to birnessite loadings under the same experimental conditions, the surface-normalized specific rate constant, $K_{surf}$, for 1,4-NPQ was determined to be $8.5{\times}10^{-4}L/m^2{\cdot}hr$. The analysis of the kinetic data with respect to birnessite loading indicated that the cross-coupling reactions of 1,4-NPQ consist of two different reaction steps over time and the results have also been discussed in terms of the reaction mechanisms.

• Journal of the Korean Chemical Society
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• v.24 no.6
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• pp.444-451
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• 1980

In order to further elucidate the process of electron solvation in liquids, the medium effect, as the difference between the free energy of $H^+$ in aqueous and non-aqueous states (${\Delta}{\Delta}G_0$), of THF-water mixtures has been investigated. (${\Delta}{\Delta}G_0$) were determined by electromotive force masurements of the cell Pt$H_2Q$, Q, HCI, THF, $H_2O$|KC1 | $Hg_2Cl_2$|Hg(Pt), where $H_2Q$ and Q are hydroquinone and quinone respectively. The effect of dielectric constant on the difference of free energy and the absorption energy of solvated electrons have been studied. For the consideration of these effect the polymerization of water in THF has been studied. Near infrared spectrum of O-H stetching energy has been used to measure the extent of water aggregates. The expermental results indicate that at least in some composition of binary mixtures the electrons or other ions are solvated preferentially with one component of solvents.

• Korean Journal of Agricultural Science
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• v.48 no.1
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• pp.119-131
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• 2021

Over-produced reactive oxygen species (ROS) exert oxidative damage on lipids, proteins, and DNA in the human body, which leads to the onset of neurodegenerative diseases such as Alzheimer's disease (AD). In this study, we explored the cellular antioxidant effect of Cirsium japonicum var. maackii (CJM) against hydrogen peroxide (H₂O₂)-induced oxidative stress in neuronal cells. The antioxidant activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 2',7'-dichlorofluorescin diacetate and nitric oxide (NO) assays, and the molecular mechanisms were examined by Western blot analysis. H₂O₂ treatment of SH-SY5Y cells decreased cell viability and increased ROS and NO production compared to H₂O₂-untreated cells. However, CJM increased cell viability and decreased ROS and NO accumulation in the H₂O₂-treated SH-SY5Y cells compared to H₂O₂-treated control cells. Especially, the EtOAc fraction from CJM showed the strongest antioxidant effect compared with the other extracts and fractions. Therefore, we further examined the CJM mechanism against oxidative stress using the EtOAc fraction from CJM. The EtOAc fraction up-regulated the expressions of heme oxygenase-1, NAD(P)H quinone oxidoreductase 1, and thioredoxin reductase 1. These results indicate that CJM promotes the activation of antioxidative enzymes, which eliminate ROS and NO, and further leads to an increase in the cell viability. Taken together, our results show that CJM exhibited an antioxidant activity in H₂O₂-treated SH-SY5Y cells, and it could be a novel antioxidant agent for the prevention or treatment of neurodegenerative disease such as AD.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.571-576
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• 1994

One strain of cellulose-producing Acetobacter was isolated from the traditionally fermen- ted grape vinegar in Korea. The isolated strain, designated as KI strain was identified as the Acetobacter xylinum with respect to physiological and biochemical characteristics. KI produced acetic acid from ethanol, and then decomposed acetate to CO$_{2}$ and H$_{2}$O. When the isolated strain was cultivated statically in broth culture, a thick cellulose pellicle was formed. KI was tolerance of 8% ethanol and 30% glucose, and the isolate was positive in ketogenesis from glycerol, $\gamma$-pyrone from glucose and fructose, and 2-ketogluconic acid from glucose. KI strain possessed straight-chain C$_{18:1}$, C$_{16:0}$, and C$_{14:0}$ fatty acid, and contained ubiquinone Q$_{9}$ and Q$_{10}$ as isoprenoid quinone. DNA base composition of KI strain was 57.6% G+C.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2381-2386
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• 2009

The tetrakis(thio)-substituted-1,4-benzoquinone products 4a-e, 6, 7, and the mono(alkoxy)-tris(thio)-substituted-1,4- benzoquinone products 5a-e and 8a-e were synthesized from the reactions of p-chloranil with some thiols and mixture of two different thiol compounds in alcohol in the presence of $Na_2CO_3$ at room temperature. The structures of the novel S,S,S,S- and S,S,S,O- substituted products, which were obtained by the reactions of p-chloranil as a starting compound with n-propanethiol, n-pentanethiol, n-decanethiol, n-dodecanethiol, 2-methyl-2-propanethiol, and mixture of n-decanethiol and n-cyclohexanethiol as S-nucleophiles, were characterized by spectroscopic methods.

• Journal of Life Science
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• v.16 no.3 s.76
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• pp.369-374
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• 2006

Six fractions of Salvia miltiorrhiza were tested for their chemopreventive potentials using biochemical markers of carcinogenesis such as quinone reductase (QR), glutathione S-transferase (GST) and glutathione (GSH). Seventy percentage of EtOH extract was potent inducer of QR activity in Hepa1c1c7 murine hepatoma cells. GST activity was increased about 1.4-fold with EtOAc extract at concentration of 50 ${\mu}g/ml$. GSH levels were significantly increased with $H_2O$ extract, 70% EtOH extract and water extract at concentration of 50 ${\mu}g/ml$ (p<0.005). From these results, 70% EtOH extract (250 mg/kg) was intragastrically administered to ICR mice for 14 days. QR, GST and GSH levels were significantly increased with the 70% EtOH treatment. These studies suggest that the 70% EtOH extract of S. miltiorrhiza could be considered as a potential agent for cancer chemoprevention.

• Journal of the Korean Wood Science and Technology
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• v.9 no.2
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• pp.1-30
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• 1981

To investigate the formation of the chromophoric structures taking place during the alkaline pulping vanillyl alcohol [${\alpha}-^{13}C$] guaiacylglycerol-${\beta}$-aryl ether [${\alpha}-^{13}C$ or ${\gamma}-^{13}C$] and phenylcoumarn [${\alpha}-^{13}C$] units as model lignins were treated with 1N sodium hydroxide at 165$^{\circ}C$ for 1.5-3 hours. From the chemical structures of the isolated products and $^{13}C$-NMR Spectra of the reaction mixtures, the main conclusion is as follows; 1) Condensation products of II-1-5 were identified from the reaction mixture of vanillyl alcohol treated with alkali and theses compounds afforded the quinonmethide structure(Fig. 3-7) by air oxidation. 2) Treatment of guaiacylglycerol-${\beta}$-aryl ether unit gave ${\varphi}$-aryl-${\beta}$-aroxy quinone structures (IV-15, IV-16), diguaiacyl-1, 4-penta-diene ${\beta}$, ${\beta}$'-diaroxyl distyrene methane unit, ${\beta}$-aroxy distyrene methane. These distyrene methanes of the compounds are transformed by air oxidation into the corresponding o-quinonemethide units (V-8, V-9). 3) On the treatment of phenylcoumaran, the stilbene derivative was formed in quantitative yield and dimerized(VI-11) in preference to oxidation to the corresponding extended quinone structures. The chromophoric structures taken place during the alkaline treatment of the model lignins are thought to be some important types in alkaline pulping on the basis of the reaction mechanism in this experiment.

• Korean Journal of Microbiology
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• v.31 no.2
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• pp.99-104
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• 1993

Two strains of the gram-negative acetic acid bacteria, Acetobacter sp. strain CS2- AND CS5, were isolated form the traditional raw rice wine vinegar of Haenam area. The strains oxidized ethanol to acetic acid and over-oxidized acetate and lactate to $CO^{2}$ and $H ^{2}$O. They produced 2-ketogluconic acid from glucose but did not produce .gamma.-pyrones from glucose and dihydroxyacetone from glycerol. The CS strains possessed ubiquinone-9 as a major isoprenoid quinone and contained straight-chain $C_{18 :1}$, $_C{16 : 0}$, and $C _{14 : 0}$ fatty acids. The DNA base composition of the CS2 and CS5 strains was 56.2 and 57.3 mole% G + C, respectively. The isolates were grown well on methanol, gluconate, erythritol, raffinose, dulcitol and xylitol as sole sources of carbon and energy which are different from those of other Acetobacter species and producedd acid from sucrose, glycerol, fructose, inositol, mannitol, and ribose.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.43-49
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• 2001

Indole and its derivatives form a class of toxic recalcitrant environmental pollutants, Abacte-rium, strain KL-9 was isolated from soil with indole as a sole source of carbon and nitrogen. KL-9 was identified as Acinetobacter sp. on the basis of 16 S rRNA gene sequence, fatty acid and quinone compositions. This identification was also confirmed by the ability of carbon source utilization and other biochemical tests. The growth of Acinetobacter sp. KL-9 was fastest with 0.3mg/ml of indole as was inhibited by higher than 0.5mg/ml of indole in the medium, KL-9 with indole also produced indigo. The formation of indigo was stimulated inthe presence of glucose, which is not a growth-suppoting carbon source for KL-9. Additional biotransformation evidence showed that anthranilate is an intermediate for the degradation of indole KL-9.