• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.310-316
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• 2001

To find out the effect of low temperature on the regulation of tomato chloroplast genes, the optimization of the system in chloroplast protein synthesis and the identification of the changes in chloroplast protein synthesis induced by chilling were studied. Incorporation reaction occurred rapidly at the first 30 minutes and was constantly maintained after 60 minutes. A broad optimal temperature on protein synthesis was found around 20 to $30^{\circ}C$. No difference was shown in the chloroplast protein synthesis under high light intensity (1600 ${\mu}E/m^2/s$) as well as under low light intensity (400 ${\mu}E/m^2/s$) even darkness. $K^+$, $Mg^{++}$ and ATP at an optimal concentration act as an activator, while DTT, chloramphenicol, cycloheximide, $Ca^{++}$ and inorganic phosphate act as an inhibitor in the chloroplast protein synthesis. Synthesis of 15, 55 and 60 kd chloroplast encoded stromal proteins and 18, 24, 33 and 55 kd chloroplast encoded thylakoid membrane proteins were reduced by chilling, while 17 kd chloroplast encoded stromal protein and 16 kd chloroplast encoded thylakoid membrane protein was induced by chilling. It was expected that the 55 kd stromal protein would be the large subunit of rubisco and the 33 kd thylakoid membrane protein would be the D1 protein which was drastically reduced by chilling.

• Journal of Microbiology
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• v.34 no.2
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• pp.192-197
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• 1996

L-Xylosone was detected as its quinoxaline derivative in the degradation solution of dehydro-L-ascorbic acid. The production rate of L-xylosone was much faster in aerated phosphate-cirate buffer (pH 5. 6) than in pure water. L-Xylosone and dehydro-L-ascorbic acid were identified in the crude extracts of Saccharomyces cerevisiae. The concentration of L-xylosone in the crude cell extracts was calculated to be about 0.2 nmol $(mg protein)^{-1}$. When L-xylosone was added to asynchronous culture of S. cerevisiae, it inhibited primarily the synthesis of protein and RNA. Examination of the effect of L- xylosone on synchronous culture of the yeast indicated that L-xylosone inhibited the initiation of DNA replication and that the cells were arrested at $G_1$, stage of cell division cycle. These results suggested a possibility that L-xylosone can act as an inhibitor of cell growth.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.736-741
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• 2000

The abilities of petroleum ether-extracts prepared from 75 plants to inhibit tyrosinase activity were evaluated in reverse micelles composed of isooctane/AOT(100 mM)/phosphate buffer(20 mM, pH 8.0) containing tyrosinase(105.3 units/mL) and 3,4-dihydroxyphenylalanine(0.18 mM). Compared with control which has no plant extracts, garlic could completely inhibit in vitro melanogenesis by tyrosinase, and Chinese quince, sweet potato, onion, radish bud and apple did more than 60%. Lipophilic extracts of medicinal plants and herbs such as rosemary, coriander, cinnamomi ramulus, crataegii fructus, ramulus biotae folium, mume fructus, menthae herba, eucommiae cortex and clove also inhibited tyrosinase activity more than 60%. When the extraction yield of lipophilic materials was considered together with their inhibition effect on tyrosinase, it was possible to select plants of which tyrosinase inhibitors could be produced in high quantity from unit weight. Using reverse micelles, the analysis of the capacity of lipophilic materials to inhibit tyrosinase activity which was difficult up to present could be possible.

• Corrosion Science and Technology
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• v.14 no.5
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• pp.213-217
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• 2015

Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

• Journal of Acupuncture Research
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• v.22 no.2
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• pp.55-70
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• 2005

Objective: Ulmus davidiana Planch (Ulmaceae) has long been known to have anti-inflammnatory in the traditional Korean medicine. UD has been reported as a good enhancer for bone healing. Methods : In this experiment, we investigate the Inhibitory effects of UD on bone resorption using the bone cells culture. Different concentrations of crude extract of UD were added to mouse bone cells culture. The mitochondria activity of the bone cells after exposure was determined by colorimetric MIT assay. It was demonstrated that UD has potential effects on bone cells culture without any cytotoxicity. The most effective concentration of UD on bone cells were $100\;{\mu}g/ml$. Cathepsin K (Cat K) is the major cysteine protease expressed in osteoclasts and is thought to play a key role in matrix degradation during bone resorption. Results : When mouse long bone cells including osteoclasts and osteoblast were treated with the PI3-Kinase inhibitor, wortmannin (WT), WT prevented the osteoclast-mediated intracellular processing of Cat K. Similarly, treatment of osteoclasts-containing long bone cells with UD extracts prevented the intracellular maturation of Cat K, suggesting that UD may disrupt the intracellular trafficking of pro Cat K. This is similar to that of WT. Since secreted proenzymes have the potential to reenter the cell via mannose-6-phosphate (M6P) receptor, to prevent this possibility, we tested WT and UD in the absence or presence of M6P. Inhibition of Cat K processing by WT or UD was observed in a dose-dependent manner. Furthermore, the addition of M6P resulted in enhanced potency of WT and UD. Conclusion : UD dose-dependently inhibited in vitro bone resorption with a potency similar to that observed for inhibition of Cat K processing.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.766-775
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• 2011

We investigated the effect of high molecular weight polygamma- glutamic acid (hm ${\gamma}$-PGA) on adiposity and lipid metabolism of rats in the presence of an obesity-inducing diet. Thirty-two Sprague-Dawley rats were fed either a normal-fat (11.4% kcal fat, NFC) or high-fat (51% kcal fat, HFC) diet. After 5 weeks, half of each diet-fed group was treated with hm ${\gamma}$-PGA (NFP or HFP) for 4 weeks. The HFC group had significantly higher body weight, visceral fat mass, fasting serum levels of total cholesterol, LDL cholesterol, and leptin, and lower serum HDL cholesterol level compared with those of the NFC group (p < 0.05). Treatment with hm ${\gamma}$-PGA decreased body weight gain and perirenal fat mass (p<0.05), fasting serum total cholesterol, and mRNA expression of glucose-6- phosphate dehydrogenase (G6PD), regardless of dietary fat contents (p < 0.01). However, hm ${\gamma}$-PGA increased serum HDL cholesterol in the HFC group (p < 0.05). In vitro, 3-hydroxy-3-methylglutaryl coenzyme-A (HMGCoA) reductase activity was suppressed by the addition of hm ${\gamma}$-PGA. In agreement with observations in animal study, the supplementation of hm ${\gamma}$-PGA (150 mg/day) to 20 female subjects in an 8-week double-blind, placebocontrolled study resulted in a tendency to decrease total cholesterol and LDL cholesterol concentrations. We thus conclude that dietary supplementation of hm ${\gamma}$-PGA may act as a hypocholestrolemic agent, secondary to its inhibitor effect on HMG-CoA reductase, and decrease abdominal adiposity by decreasing hepatic lipogenesis. The present study is an important first step in establishing the effect of hm ${\gamma}$-PGA on cholesterol levels in rats and humans.

• Development and Reproduction
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• v.24 no.4
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• pp.297-306
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• 2020

Repetitive changes in the intracellular calcium concentration ([Ca²⁺]i) triggers egg activation, including cortical granule exocytosis, resumption of second meiosis, block to polyspermy, and initiating embryonic development. [Ca²⁺]i oscillations that continue for several hours, are required for the early events of egg activation and possibly connected to further development to the blastocyst stage. The sources of Ca²⁺ ion elevation during [Ca²⁺]i oscillations are Ca²⁺ release from endoplasmic reticulum through inositol 1,4,5 tri-phosphate receptor and Ca²⁺ ion influx through Ca²⁺ channel on the plasma membrane. Ca²⁺ channels have been characterized into voltage-dependent Ca²⁺ channels (VDCCs), ligand-gated Ca²⁺ channel, and leak-channel. VDCCs expressed on muscle cell or neuron is specified into L, T, N, P, Q, and R type VDCs by their activation threshold or their sensitivity to peptide toxins isolated from cone snails and spiders. The present study was aimed to investigate the localization pattern of N and P/Q type voltage-dependent calcium channels in mouse eggs and the role in fertilization. [Ca²⁺]i oscillation was observed in a Ca²⁺ contained medium with sperm factor or adenophostin A injection but disappeared in Ca²⁺ free medium. Ca²⁺ influx was decreased by Lat A. N-VDCC specific inhibitor, ω-Conotoxin CVIIA induced abnormal [Ca²⁺]i oscillation profiles in SrCl₂ treatment. N or P/Q type VDC were distributed on the plasma membrane in cortical cluster form, not in the cytoplasm. Ca²⁺ influx is essential for [Ca²⁺]i oscillation during mammalian fertilization. This Ca²⁺ influx might be controlled through the N or P/Q type VDCCs. Abnormal VDCCs expression of eggs could be tested in fertilization failure or low fertilization eggs in subfertility women.

• BMB Reports
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• v.52 no.3
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• pp.220-225
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• 2019

We have identified a mechanism to diminish the proliferative capacity of cells during cell expansion using human adipose-derived stromal cells (hAD-SCs) as a model of replicative senescence. hAD-SCs of high-passage numbers exhibited a reduced proliferative capacity with accelerated cellular senescence. Levels of key bioactive sphingolipids were significantly increased in these senescent hAD-SCs. Notably, the transcription of sphingosine kinase 1 (SPHK1) was down-regulated in hAD-SCs at high-passage numbers. SPHK1 knockdown as well as inhibition of its enzymatic activity impeded the proliferation of hAD-SCs, with concomitant induction of cellular senescence and accumulation of sphingolipids, as seen in high-passage cells. SPHK1 knockdown-accelerated cellular senescence was attenuated by co-treatment with sphingosine-1-phosphate and an inhibitor of ceramide synthesis, fumonisin $B_1$, but not by treatment with either one alone. Together, these results suggest that transcriptional down-regulation of SPHK1 is a critical inducer of altered sphingolipid profiles and enhances replicative senescence during multiple rounds of cell division.

• The Korea Journal of Herbology
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• v.36 no.2
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• pp.31-42
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• 2021

Objectives : This study was undertaken to investigate the hepatoprotective effect of Spatholobi Caulis water extract (SC) to thioacetamide (TAA)-induced acute liver injury (ALI) in rats. Methods : The rats were injected intraperitoneally with TAA (200 mg/kg body weight) and orally administered SC (100 or 200 mg/kg b.w.) daily for 3 days. Liver biomarkers were assessed by serum glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and ammonia levels. Malondialdehyde (MDA) was measured both serum and liver tissue. In addition, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, anti-oxidant, and inflammation-related proteins were investigated by western blot analysis. Histological examination further confirmed though hematoxylin and eosin stain. Results : The SC treatment reduced liver function markers like GOT and GPT and also remarkably decreased ammonia level. Moreover, the elevated MDA level in TAA-induced group was significantly reduced by SC treatment. NADPH oxidase expression associated with oxidative stress including NOX2, NOX4, and p47phox markedly inhibited by SC administration. SC treatment exerted anti-oxidant effect through the increase of anti-oxidant enzyme including superoxide dismutase (SOD), Catalase, and heme oxygenase-1 (HO-1). The protein expressions of inflammatory cytokines such as tumor necrosis factor-�� (TNF-��), IL-6, and IL-1�� induced by nuclear factor-kappa B (NF-��B) activation were modulated through blocking the phosphorylation of inhibitor of nuclear factor ��B�� (I��B)��. SC treatment also improved histological alterations. Conclusion : These findings suggested that SC administration may be a potential candidate for the prevention or treatment of ALI.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.51-61
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• 2010

Ettringite $(Ca_6[Al(OH)_6]_2(SO_4)_3{\cdot}26H_2O)$ is a sulfate mineral that shows a complicate property in concrete. It is often called as "a cancer of concrete" because secondary ettringite formation in hardened concrete often cause expansion and cracking of concrete due to its expansive crystal structure. In the present study, we tested the possibility for crystal growth inhibition of secondary ettringite by crystallization inhibitors that are commercially used for scaling inhibitors in Korea. For the test, we developed a method of ettringite solution synthesis. Three types of crystallization inhibitors were selected and examined the effects On ettringite growth inhibition. The experimental results of ettringite solution synthesis indicated that ettringite was successfully synthesized under condition that the mass balance between calcium hydroxide saturated solution and aluminum sulfate solution was attained. Monosulfate and semisulfate were synthesized when the ratio of $Ca^{2+}$ ions to ${SO_4}^{2+}$ ions was increased. The induction time of ettringite crystallization was less than 2 min. and crystallization was almost completed within an hour. The experimental results of ettringite crystallization inhibition showed that organic PBCT (2-Phosphonobutane-1,2,4-Tricarboxylic Acid) and inorganic SHMP (Sodium Hexametaphosphate) were relatively less effective on ettringite crystallization inhibition under experimental conditions. However, organic HEDP (1-Hydoxyethylidene-1,1-Diphosphonic Acid) effectively prevented ettringite growth with producing amorphous gel phase materials up to inhibitor concentration 0.1 vol.% of aluminum sulfate solution.