• Journal of Life Science
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• v.25 no.3
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• pp.336-344
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• 2015

The capacity for liver regeneration involves a variety of nutritional factors. Vitamin C has multiple metabolic and antioxidant functions. In this study, we investigated the role of vitamin C in liver regeneration following hepatectomy in senescence marker protein (SMP)-30 knockout (KO) mice. Partial hepatectomy was performed by resecting the median and left lateral lobes of mice. Vitamin C accelerated liver recovery in SMP30 KO mice treated with vitamin C (KV). The livers of the KV mice exhibited lower levels of aspartate aminotransferase and lower injury than those of the KO mice. Increased type II transforming growth factor-β receptor (TGF-βRII)-mediated regeneration signaling was accompanied by HGF and cMet in the KV but not the KO mice. Consistent with this, the expression of cell cycle regulatory proteins, including cyclin D1 and proliferating cell nuclear antigen (PCNA), increased rapidly in the KV mice. Enhanced activation of ERK and GSK-3β proteins and a significantly increased number of binuclear hepatocytes were also detected in the livers of the KV mice. Moreover, the KV mice synthesized the highest levels of albumin. These data suggest that treating SMP30 knockout mice with vitamin C resulted in earlier recovery and liver regeneration by activation of the regeneration system.

• Journal of Life Science
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• v.23 no.4
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• pp.586-594
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• 2013

Post-translational O-GlcNAc modification (O-GlcNAcylation) of serine or threonine is a new protein modulation mechanism. In contrast to the classical glycosylation, O-GlcNAcylation occurs in a one-step transfer of O-GlcNAc on both nuclear and cytoplasmic proteins. In contrast to the general consensus that O-GlcNAc is a final modification, a recent paper (J Proteome Res. 2011 10:2725-2733) showed the presence of O-GlcNAc-P on a synaptic assembly protein AP180. This finding raises a fundamental question about its prevalence. To address this question, we used proteomics to identify those proteins that were phospho-signal enriched by GlcNAc kinase (NAGK). Comparison of pDsRed2-$NAGK_{WT}$-transfected HEK293T cell extract with pDsRed2-$NAGK_{D107A}$-transfected control culture revealed 15 phospho-signal increased spots. Excluding those spots that had no detectable amount of protein expression yielded 7 spots, which were selected for ID determination. Among these, two duplicate spots (two $HSP90{\beta}$ and two ENO1 spots) were shown to be O-GlcNAcylated, two (dUTP nucleotidohydrolase mitochondrial isoform 2, glutathione S-transferase P) were not known to be involved in O-GlcNAcylation, and one (heat shock protein gp96 precursor or grp94) was a glycoprotein. The increase in the phospho-levels of O-GlcNAc by NAGK strongly indicates that these proteins are phosphorylated on O-GlcNAc. Our present data support the idea that O-GlcNAc is not a terminal modification.

• Molecules and Cells
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• v.38 no.4
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• pp.373-379
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• 2015

Pyruvate kinase M2 isoform (PKM2), a rate-limiting enzyme in the final step of glycolysis, is known to be associated with the metabolic rewiring of cancer cells, and considered an important cancer therapeutic target. Herein, we report a novel PKM2 activator, PA-12, which was identified via the molecular docking-based virtual screening. We demonstrate that PA-12 stimulates the pyruvate kinase activity of recombinant PKM2 in vitro, with a half-maximal activity concentration of $4.92{\mu}M$, and effectively suppresses both anchorage-dependent and -independent growth of lung cancer cells in non-essential amino acid-depleted medium. In addition, PA-12 blocked the nuclear translocalization of PKM2 in lung cancer cells, resulting in the inhibition of hypoxia response element (HRE)-mediated reporter activity as well as hypoxia-inducible factor 1 (HIF-1) target gene expression, eventually leading to the suppression of cell viability under hypoxia. We also verified that the effects of PA-12 were dependent on PKM2 expression in cancer cells, demonstrating the specificity of PA-12 for PKM2 protein. Taken together, our data suggest that PA-12 is a novel and potent PKM2 activator that has therapeutic implications for lung cancer.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.19-32
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• 2010

Electrolytic reduction technology is essential for the purpose of adopting pyroprocessing into spent oxide fuel as an alternative option in a back-end fuel cycle. Spent fuel consists of various metal oxides, and each metal oxide releases an oxygen element depending on its chemical characteristic during the electrolytic reduction process. In the present work, an electrolytic reduction behavior was estimated for voloxidized spent fuel based on the assumption that each metal-oxygen system is independent and behaves as an ideal solid solution. The electrolytic reduction was considered as a combination of a Li recovery and chemical reactions between the metal oxides such as uranium oxide and the produced Li metal. The calculated result revealed that most of the metal oxides were reduced by the process. It was evaluated that a reduced fraction of lanthanide oxides increased with a decreasing $Li_2O$ concentration. However, most of the lanthanides were expected to be stable in their oxide forms. In addition, a semi-empirical model for describing $U_3O_8$ electrolytic reduction behavior was proposed by considering Li diffusion and a chemical reaction between $U_3O_8$ and Li. Experimental data was used to determine model parameters and, then, the model was applied to calculate the reduction yield with time and to estimate the required time for a 99.9% reduction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.65-70
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• 2010

The distillation rate on LiCl-KCl eutectic salt under different vacuums from 0.5-50 mmHg was first investigated by using both a non-isothermal and a isothermal thermogravimetric (TG) analysis. Based on the non-isothermal TG data, distillation rate equations as a function of the temperature could be derived. Calculated flux by these model flux equations was in agreement with the distillation rate obtained from isothermal TG analysis. A distillation rate of $10^{-4}-10^{-5}$ mole $cm^{-2}sec^{-1}$ is obtainable at temperatures less than 1300K and vacuums of 0.5-50 mmHg. About a 99% salt distillation efficiency was obtained after an hour at a temperature above 1150 K under 50 mmHg in a small scale distillation test system. An increase in the vaporizing surface area is relatively effective for removing residual salt in the remaining particles, when compared to that for the vaporizing time. Over 99.95% of total distillation efficiency was obtained for a 1-h distillation operation by increasing the inner surface area from $4.52cm^2$ to $12.56cm^2$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.1
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• pp.69-77
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• 2014

Unsaturated hydraulic conductivity of the bentonite-buffer was evaluated using the relative humidity data. The method for calculating unsaturated hydraulic conductivity was deduced from the general analytical equation representing the movement of water in unsaturated media, which was applied to the experimental results of water infiltration tests for identifying the behavior of unsaturated hydraulic conductivity according to the water saturation. Unlike the saturated condition, the hydraulic gradient and water flux were irregularly changed, and the unsaturated hydraulic conductivity was increased with increasing the experimental time. Swelling of bentonite grains due to the water absorption increased the volume and size of pore within bentonite, resulting in the increase of water velocity and unsaturated hydraulic conductivity. This result suggested the necessity of further investigation on the correlation between the swelling degree of bentonite-buffer and unsaturated hydraulic conductivity. The method used in this study can be useful technique for evaluating long-term hydraulic performance of bentonite-buffer in the radioactive waste disposal system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.199-206
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• 2017

A geological repository for the disposal of high-level radioactive waste is generally constructed in host rock at depths of 500~1,000 meters below the ground surface. A geological repository system consists of a disposal canister with packed spent fuel, buffer material, backfill material, and intact rock. The buffer is indispensable to assure the disposal safety of high-level radioactive waste, and it can restrain the release of radionuclides and protect the canister from the inflow of groundwater. Since high temperature in a disposal canister is released to the surrounding buffer material, the thermal properties of the buffer material are very important in determining the entire disposal safety. Even though there have been many studies on thermal conductivity, there have been only few studies that have investigates the specific heat capacity of the bentonite buffer. Therefore, this paper presents a specific heat capacity prediction model for compacted Gyeongju bentonite buffer material, which is a Ca-bentonite produced in Korea. Specific heat capacity of the compacted bentonite buffer was measured using a dual probe method according to various degrees of saturation and dry density. A regression model to predict the specific heat capacity of the compacted bentonite buffer was suggested and fitted using 33 sets of data obtained by the dual probe method.

• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.323-330
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• 2016

Pinellia ternata Breitenbach, the natural medicinal plant of the Araceae family, is a perennial plant originated from the East Asia, but also widely distributed in Europe and North America. Its tuber is used as traditional medicine for treatment of various diseases such as vomiting, inflammation, and traumatic injury. Pharmacological studies revealed that P. ternata possesses anticonvulsant, anti-tumor, insecticidal, and cytotoxic activities. Despite being well-known as the useful medicinal plant, there is no reliable, standardized method for origin discrimination. Ultra performance liquid chromatography-photodiode array detector and quadrupole time of flight-mass spectrometry based metabolite-profiling was applied to explore significant metabolite for origin discrimination between Korean and Chinese P. ternata. One compound was isolated from Korean P. ternata using repeated ODS column chromatography by bioactivity guided fractionation, and determined as [6]-gingerol according to the results of spectroscopic data including nuclear magnetic resonance and MS. This compound was selected as cosmeceutical biomarker by fingerprints, and it was associated to melanin inhibitory effect determining its origin authenticity. Furthermore, the calibration curve of biomarker was prepared using validated method for the comparison of content between Korean and Chinese P. ternata. This is the report to address the selection and successful validation of the discriminant metabolite for confirmation of Korean P. ternata.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.378-384
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• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• Journal of Ginseng Research
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• v.39 no.2
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• pp.162-168
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• 2015

Background: Although the aerial parts of hydroponic Panax ginseng are reported to contain higher contents of total ginsenosides than those of roots, the isolation and identification of active metabolites from the aerial parts of hydroponic P. ginseng have not been carried out so far. Methods: The aerial parts of hydroponic P. ginseng were applied on repeated silica gel and octadecylsilane columns to yield four glycosyl glycerides (Compounds 1-4), which were identified based on nuclear magnetic resonance, infrared, fast atom bombardment mass spectrometry, and gas chromatography/mass spectrometry data. Compounds 1-4 were evaluated for inhibition activity on NO production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Results and conclusion: The glycosyl glycerides were identified to be (2S)-1-O-7(Z),10(Z),13(Z)-hexadecatrienoyl-3-O-${\beta}$-$\small{D}$-galactopyranosyl-sn-glycerol (1), (2S)-1-O-linolenoyl-3-O-${\beta}$-$\small{D}$-galactopyranosyl-sn-glycerol (2), (2S)-1-O-linolenoyl-2-O-linolenoyl-3-O-${\beta}$-$\small{D}$-galactopyranosyl-sn-glycerol (3), and 2(S)-1-O-linoleoyl-2-O-linoleoyl-3-O-${\beta}$-$\small{D}$-galactopyranosyl-sn-glycerol (4). Compounds 1 and 2 showed moderate inhibition activity on NO production in LPS-stimulated RAW264.7 cells [half maximal inhibitory concentration ($IC_{50}$): $63.8{\pm}6.4{\mu}M$ and $59.4{\pm}6.8{\mu}M$, respectively] without cytotoxicity at concentrations < $100{\mu}M$, whereas Compounds 3 and 4 showed good inhibition effect ($IC_{50}$: $7.7{\pm}0.6{\mu}M$ and $8.0{\pm}0.9{\mu}M$, respectively) without cytotoxicity at concentrations < $20{\mu}M$. All isolated compounds showed reduced messenger RNA (mRNA) expression of interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, and tumor necrosis factor-${\alpha}$ in LPS-induced macrophage cells with strong inhibition of mRNA activity observed for Compounds 3 and 4.