• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.91-95
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• 2008

Reactive oxygen species(ROS) or free radical-mediated oxidative stress plays an important role in the pathophysiologic process of disease state. This study investigated antioxidative effects of Phellinus linteus extract on the generation of 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, superoxide anion radical(${O_2}^-$), hydroxyl radical(${\cdot}OH$), nitric oxide(NO), and peroxynitrite($ONOO^-$) radical and free radical-mediated protein oxidation under in vitro assay systems. This results showed that Phellinus linteus extract effectively inhibited the generation of free radicals in the all assay system with dose-dependent manner and also significantly reduced the protein oxidative level. Thus, the present study indicates that Phellinus linteus extract possesses a potent antioxidant activity and plays a beneficial role against free radical-induced oxidative injury.

• Journal of Welding and Joining
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• v.33 no.4
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• pp.30-36
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• 2015

Austenite stainless steel(SA213-TP347H) has widely been used for the superheater & reheater tube in USC(ultra-supercritica) coal boiler because of its high creep rupture strength and anti-oxidation. But recently, the short-term failures have happened frequently in heat affected zone for only 4,000~15,000hours of service. Many investigations have been conducted to understand the failure mechanism. The root cause of failure was comfirmed to "strain induce participation hardening crack" or "reheat cracking". This mechanism often occurred due to weld residual stress and precipitation of the Cr, Nb carbides in the stabilized stainless steel such as TP347H. This paper presents an analysis of failure tube and effect of the sample tubes that conducting stabilizing heat treatment in site after 11,380hours & 16,961hours of service. Visual inspection was performed. In addition, microscopic characteristics was identified by O.M, SEM, and hardness test was carried out to find out the heat treatment effects. Failures seem to happen because of being not conducted stabilizing heat treatment in site. And another cause is inadequate weld parameter such as pass, ampere, voltage, inter-pass temperature. Thus, this paper has the purpose to describe that how to prevent similar failures in those weld-joints.

• The Journal of Korean Medicine
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• v.25 no.2
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• pp.127-137
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• 2004

Objectives : The purpose of this investigation was to evaluate the effects of Sohaphyang-won (SH) on the alteration in gene expression in a hypoxia model using cultured rat cortical cells. Methods : E18 rat cortical cells were grown in neurobasal medium containing B27 supplement. On 12 DIV, SH was added ($20\mu\textrm{g}/ml$) to the culture media for 24 hrs. On 14 DIV, cells were given a hypoxic insult (2% O2/5% CO2, $37^{\circ}C$, 3 hrs), returned to normoxia and cultured for another 24 hrs. Total RNA was prepared from SH-untreated (control) and -treated cultures and alteration in gene expression was analyzed by microarray using rat 5K-TwinChips. Results : Effects on some of the genes whose functions are implicated in neural viability are as follows: 1) For most of the genes altered in expression, the global M values were between -05 to +0.5, Among these, 1517 genes were increased in their expression by more than global M +0.1, while 1480 genes were decreased by more than global M -0.1. 2) The expression of apoptosis-related genes such as Bad (global M =0.35), tumor protein p53 (T53) (global M =0.28) were increased, while v-akt murine thymoma viral oncogene homolog 1 (Akt1) was decreased. 3) The expression of hemoglobin alpha 1 (probably neuroglobin) was increased by about 3.2-fold (global M =1.7). 4) The expression of antioxidation-related catalase gene was increased (global M =0.26). 5) The expression of PKCzeta (prkcz), an upstream kinase of MAPK, was increased (global M =0.29). 6) The expression of retinoic acid receptor alpha (RAR), which may regulate transcription in hypoxic stress, was increased (global M =10.27). Conclusions : In summary, the microarray data suggest that SH doesn't increase the expression of oxygen capture-, anti-oxidation- and 'response to stress' -related genes but decreases some anti-apoptosis genes which would help protect the hypoxic cells from apoptosis.

• Nutrition Research and Practice
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• v.9 no.6
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• pp.592-598
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• 2015

BACKGROUND/OBJECTIVES: Increased mass of adipose tissue in obese persons is caused by excessive adipogenesis, which is elaborately controlled by an array of transcription factors. Inhibition of adipogenesis by diverse plant-derived substances has been explored. The aim of the current study was to examine the effects of the aqueous methanol extract of laver (Porphyra yezoensis) on adipogenesis and apoptosis in 3T3-L1 adipocytes and to investigate the mechanism underlying the effect of the laver extract. MATERIALS/METHODS: 3T3-L1 cells were treated with various concentrations of laver extract in differentiation medium. Lipid accumulation, expression of adipogenic proteins, including CCAAT enhancer-binding protein ${\alpha}$, peroxisome proliferator-activated receptor ${\gamma}$, fatty acid binding protein 4, and fatty acid synthase, cell viability, apoptosis, and the total content and the ratio of reduced to oxidized forms of glutathione (GSH/GSSG) were analyzed. RESULTS: Treatment with laver extract resulted in a significant decrease in lipid accumulation in 3T3-L1 adipocytes, which showed correlation with a reduction in expression of adipogenic proteins. Treatment with laver extract also resulted in a decrease in the viability of preadipocytes and an increase in the apoptosis of mature adipocytes. Treatment with laver extract led to exacerbated depletion of cellular glutathione and abolished the transient increase in GSH/GSSG ratio during adipogenesis in 3T3-L1 adipocytes. CONCLUSION: Results of our study demonstrated that treatment with the laver extract caused inhibition of adipogenesis, a decrease in proliferation of preadipocytes, and an increase in the apoptosis of mature adipocytes. It appears that these effects were caused by increasing oxidative stress, as demonstrated by the depletion and oxidation of the cellular glutathione pool in the extract-treated adipocytes. Our results suggest that a prooxidant role of laver extract is associated with its antiadipogenic and proapoptotic effects.

• Journal of Plant Biotechnology
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• v.43 no.2
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• pp.223-230
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• 2016

Ascorbic acid (AsA) is a strong antioxidant/reducing agent that can be converted to dehydroascorbate (DHA) by oxidation in plants. DHA, a very short-lived chemical, is recycled to AsA by dehydroascorbate reductase (DHAR). Previously, DHAR cDNA was isolated from the hairy roots of the sesame plant, and DHAR-overexpressing transgenic potato plants were generated under the control of the CaMV35S promoter (CaMV35S::DHAR). An increase in transgene expression and ascorbate levels were observed in the transgenic plants. In the present study, proteomic analysis revealed that transgenic plants not only accumulated DHAR in their cells, but also induced several other antioxidant enzyme-related proteins during plant growth. These results suggest that DHAR is important for stress tolerance via induction of antioxidant proteins, and could improve stress tolerance in transgenic potato plants.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1209-1216
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• 2018

This study aimed to evaluate the antimicrobial activity of 2-phenylethynyl-butyltellurium (PEBT) in Escherichia coli and the relation to its pro-oxidant effect. For this, we carried out the disk diffusion test, minimum inhibitory concentration (MIC) assay, and survival curve analysis. We also measured the level of extracellular reactive oxygen species (ROS), activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and level of non-protein thiols (NPSH). PEBT at 1.28 and 0.128 mg/disk exhibited antimicrobial capability in the disk diffusion test, with an MIC value of 1.92 mg/ml, whereas PEBT at 0.96, 1.92, and 3.84 mg/ml inhibited bacterial growth after a 9-h exposure. PEBT at 3.84, 1.92, and 0.96 mg/ml increased extracellular ROS production, decreased the intracellular NPSH level, and reduced the SOD and CAT activities. Glutathione or ascorbic acid in the medium protected the bacterial cells from the antimicrobial effect of PEBT. In conclusion, PEBT exhibited antimicrobial activity against E. coli, involving the generation of ROS, oxidation of NPSH, and reduction of the antioxidant defenses in the bacterial cells.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.23-36
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• 2005

Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces cell death when expressed In yeast. To investigate whether .Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various orgarusms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs In detail. PBIl is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Bax-induced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower lovels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. H$_{2O2}$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of H2O2 treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased In the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MBP phosphorylation activity of AtMPK3 i'n vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation In situ. Thus, AtNDPK2 appears to play a novel regulatory role in H2O2-mediated MAPK signaling in plants.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.149-158
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• 2013

We demonstrate enhanced growth, innate immunity and protection against hydrogen peroxide ($H_2O_2$)-induced protein oxidation and cellular DNA damage in olive flounder Paralichthys olivaceus fed a chitosan-coated moist pallet (MP) diet. A chitosan-based biopolymer coated MP as the experimental diet and a non-coated MP (control) was fed to olive flounder fish. Growth, including the average weight gain (g/fish), weight gain (%) and feed intake (g) of the fish group fed a chitosan-coated MP diet increased significantly. The survival rate was reported as 100% throughout the experimental period. Immunological parameters indicated higher mucus lysozyme activity and significantly higher fish skin mucus total protein content was observed in fish fed the chitosan-coated MP diet compared to the control. A blood plasma analysis revealed attenuation of cellular DNA and protein oxidative damage caused by $H_2O_2$-induced oxidative stress in the fish fed the chitosan-coated MP diet compared to the control group. Moreover, blood serum biochemical analysis revealed health-promoting effects, including significantly higher hemoglobin and total cholesterol levels in the fish fed the chitosan-coated MP diet compared to the control group. In conclusion, growth, innate immunity and protection against oxidative stresses were improved by feeding of the chitosan-coated MP diet to olive flounder reared in aquaculture.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.31-36
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• 2009

This paper focuses on techniques of improving refinery reliability, availability, and profitability. Our team developed a corrosion control document(CCD) for processing of the crude distillation unit(CDU). Recent study shows the loss due to corrosion in US is around $276 billion. It's a big concern for both managers and engineers of refinery industry. The CCD consists of numerous parts namely damage mechanism(DM), design data, critical reliability variable(CRV), guidelines, etc. The first step in the development of CCD is to build material selection diagram(MSD). Damage mechanisms affecting equipments and process need to be chosen carefully based on API 571. The selected nine DM from API 571 are (1) creep/stress rupture, (2) fuel ash corrosion, (3) oxidation, (4) high temperature sulfidation, (5) naphthenic acid corrosion, (6) hydrochloric acid(HCL) corrosion, (7) ammonium chloride(salt) corrosion, (8) wet $H_2S$ corrosion, and (9) ammonia stress corrosion cracking. Each DM related to corrosion of CDU process was selected by design data, P&ID, PFD, corrosion loop, flow of process, equipment's history, and experience. Operating variables affecting severity of DM are selected in initial stage of CRV. We propose the guidelines for reliability of equipments based on CRV. The CCD has been developed on the basis of the corrosion control in refinery industry. It also improves the safety of refinery process and reduces the cost of corrosion greatly.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.12
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• pp.1889-1896
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• 2019

Objective: This study aimed to investigate the effects of prepartum body condition score (BCS) on the milk yield, lipid metabolism, and oxidative status of Holstein cows. Methods: A total of 112 multiparous Holstein cows were divided into 4 groups according to the BCS at 21 days before calving: medium BCS (3.0 to 3.25, MBCS), high BCS (3.5 to 3.75, HBCS), higher BCS (4.0 to 4.25, HerBCS), and highest BCS (4.5 to 5.0, HestBCS). Blood samples were collected on 21, 14, and 7 days before calving (precalving), on the calving day (calving), and on 7, 14, and 21 days after calving (postcalving). The indices of lipid metabolism and oxidative status were analyzed using bovine-specific enzyme-linked immunosorbent assay kit. Colostrum were taken after calving and analyzed by a refractometer and milk analyzer. The individual milk yield was recorded every 3 days. Results: The density and levels of immune globulin and lactoprotein of colostrum from Holstein cows in the HestBCS group were the highest (p<0.05). These animals not only had the highest (p<0.05) levels of serum non-esterified fatty acids and beta-hydroxybutyrate, but also had the highest (p<0.05) levels of malondialdehyde, superoxide dismutase, catalase, vitamin A, and vitamin E. In addition, greater (p<0.05) BCS loss was observed in the HestBCS cows. Conclusion: This study demonstrates that the milk yield, lipid metabolism, and oxidative status of Holstein cows are related to prepartum BCS and BCS loss during the transition period. HestBCS cows are more sensitive to oxidative stress and suffer greater loss of BCS after calving, whereas the MBCS animals had better milk yield performance.