• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.36-39
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• 2003

Many defined cell culture media were formulated over 3() years ago and may be deficient in certain micronutrients whose essentiality has only subsequently been recognised. The objective of this study was to evaluate whether alpha-minimal essential medium (MEM) supplemented with 10% foetal bovine serum contained sufficient selenium for optimal activity of the selenium containing enzymes cytosolic glutathione peroxidase (cGPx) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) in cultured Chinese hamster ovary (CHO) cells. Additionally, the effect of zinc deficiency and metallothionein (MT) overexpression on cGPx and PHGPx activity was studied. The addition of 100 nM of selenous acid to the culture medium increased cGPx expression by 10-fold and PHGPx by about 2-fold in both wild-type CHO-K1 cells and CHO-K1 cells overexpressing mouse MT-1. Zinc deficiency had no significant effect on enzyme activity, but cells overexpressing mouse MT-1 had higher levels of cGPx activity. Zinc deficiency decreased cell survival but overexpression of MT-1 was partially protective, probably because its presence in quantity favoured the uptake, sequestration and cellular retention of any remaining zinc. This study demonstrates that selenium in complete alpha-MEM is insufficient for optimal cGPx and PHGPx activity and may compromise the cellular response to oxidative stress.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.258-264
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• 2011

Glutathione (GSH) has important roles in cellular defense against oxidative stress, 1) direct scavenging of reactive oxygen species (ROS), and 2) coenzyme of ROS scavenging enzyme like glutathione peroxidases (GPx). GSH peroxidase reduces free hydrogen peroxide to water using 2GSH. $N$-acetyl-L-cysteine (NAC), one of the antioxidants, is used as a precursor for intracellular GSH. In this study, relation of GSH, NAC, and GSH peroxidase was investigated through transcriptional expression of $GPX1$ and $GPX2$, which are GSH peroxidase encoding genes, in yeast cells treated with 0 mM to 20 mM of NAC or in combination with 100 Gy gamma-rays. The transcriptional expression of $GPX1$ and $GPX2$ was induced by NAC and 100 Gy gamma-rays. The gene expression of both GSH peroxidases was decreased with increasing concentrations of NAC in irradiated yeast cells. These results suggest that elevation of intracellular GSH by NAC and oxidative stress and ROS generated from gamma-rays induces expression of GSH peroxidase genes, and that NAC can protect the yeast cells against ROS generated from gamma-rays through direct scavenging of ROS and transcriptional activation of GSH peroxidase.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.53-59
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• 2005

The effect of various stressors such as reductant ascorbic acid, signalling molecules (salicylic acid and methyl jasmonic acid), heavy metals $(NiCl_2,\;and\;MnSO_4)$ and NaCl on the glutathione peroxidase (GPX) activities and isoenzyme expression patterns were investigated in rice seedling roots. Total GPX activity increased according to the increase of ascorbic acid concentration. Prominent enhancement of GPX1 isozyme due to ascorbic acid contributed to the increase of total GPX activity. GPX showed different reactivity toward salicylic acid and methyl jasmonic acid. GPX activity increased at 0.1 mM salicylic acid, and then decreased thereafter. However, GPX increased gradually in a methyl jasmonic acid concentration-dependent manner, and 3 fold increase of GPX activity was found at 1 mM methyl jasmonic acid. Moreover, GPX1 isozyme increased according to the increase of salicylic acid, while GPX1 isozyme decreased according to the increase of methyl jasmonic acid. When metal ions were treated, GPX activity increased considerably according to the increase of $NiCl_2$ concentration, however, GPX activity increased about 2 fold at 0.5 mM $CuSO_4$ and then decreased. Enhancement of GPX1 isozyme contributed to the increase of total GPX activities in $NiCl_2-treated$ and $MnSO_4-treated$ rice seedlings. Total GPX activity increased 1.7 fold in response to 300 mM NaCl. Especially GPX2 isozyme showed gradual increase according to the increase of NaCl concentration.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.52-57
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• 2021

Fumonisin B1 (FB1) structurally resembles sphingolipids and interferes with their metabolism leading to sphingolipid dysregulation. We questioned if FB1 could exacerbate liver or kidney toxicities in glutathione peroxidase 1 (Gpx1) and catalase (Cat) knockout mice. While higher serum levels of thiobarbituric acid reactive substances (TBARS) and sphinganine (Sa) were measured in Gpx1/Cat knockout mice (Gpx1/Cat KO) than wild type mice after 5 days of FB1 treatment, serum levels of alanine aminotransferase (ALT), sphingosine-1 phosphate (So-1-P), and sphinganine-1 phosphate (Sa-1-P) were found to be relatively low. Although Sa was highly elevated in Gpx1/Cat KO mice and wild mice, lower levels of So and Sa were found in both the kidney and liver tissues of Gpx/Cat KO mice than wild type mice after FB1 treatment. Paradoxically, FB1-induced cellular apoptosis and necrosis were hastened under oxidative stress in Gpx1/Cat KO mice.

• BMB Reports
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• v.41 no.3
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• pp.204-209
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• 2008

The cDNAs encoding glutathione peroxidase (GPx) were cloned and sequenced from the liver of three Chinese carps with different tolerance to hepatotoxic microcystins, phyto-planktivorous silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis), and herbivorous grass carp (Ctenopharyngodon idellus). Using genome walker method, a 750 bp 5'-flanking region of the silver carp GPx gene was obtained, and several potential regulatory elements were identified in the promoter region of the GPx gene. The silver carp GPx gene was widely expressed in all tissues examined. Despite phylogenetic analysis, assigning this newly described carp GPx to the group of mammalian GPx2, the carp GPx seems more similar to GPx1 from a physiological point of view. The constitutive expression pattern of the three carp liver GPx gene, shows a positive relationship with their tolerance to microcystins.

• Journal of fish pathology
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• v.25 no.1
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• pp.31-37
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• 2012

The objective of this study was to investigate the antioxidant enzyme (superoxide dismutase, SOD; glutathione, GSH; glutathione peroxidase, GPx) activities in liver and gill of rock bream, Oplegnathus fasciatus fed the experimental diets for 40 days. The experimental diets were prepared by adding with 30, 60 120 and 240 mg/kg to a commercial diet. In the liver, there were significant increases in SOD at 30~240 mg/kg. GPx activities of liver also were significantly increased at 30~120 mg/kg. The increased activities of SOD and GSH in the gills were observed in the 120 and 240 mg/kg, hence, GPx activity of gill exposed to lower concentrations of zinc (60~240 mg/kg) showed significant augmentation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.73-77
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• 2004

Selenium containing peptide was produced by culturing yeast with selenium, Selenium was broadly incorporated in the various size of proteins based on the GPC analysis of the total yeast protein. The ratio of selenium to protein increased with the concentration of added selenium in the culture medium. Antioxidant activity (glutathione peroxidase-like activity) was proportional to the concentration of selenium concentration in the peptide. Different size of proteins were obtained by hydrolyzing the total yeast protein by protease XIV. Average molecular weight of selenium peptide was analyzed by GPC. Glutathione peroxidase (GPx) activity of the selenium peptide increased as the size of peptide decreased. Sodium selenite had strong inhibition on the yeast growth than sodium selenate. The ratio of selenium to protein was higher with sodium selenate than with sodium selenite. These results showed the potentials of selenium peptide production by yeast cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.4-7
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• 2005

The pharmaceutical function of tocotrienol in rice bran was evaluated. Distinctive antioxidative effects by 1,1-diphenyl-2-picrylhydrazyl(DPPH) could be observed. Also, Superoxide Dismutase(SOD) and Glutathione Peroxidase(GPX) activities of the cultured cells such as human firbroblast and hepatocyte, were increased up to 2 fold by the treatment of tocotrienol. The effects on GPX activity were more evident than SOD activity, and the stimulation was up to 2 fold. The changes of gene expression patterns were examined by applying the cell extracts of fibroblast treated with the increasing concentrations of tocotrienol on two-dimensional gel electrophoresis(2-D gel electrophoresis). As the concentrations increasing, many proteins began to appear with the increasing amounts, while several proteins diminished or disappeared. From these results, tocotrienol was clearly shown to have abilities on protecting any oxidizing damages and stimulating anti-oxidizing activities of the organisms.

• Nutrition Research and Practice
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• v.4 no.2
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• pp.114-120
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• 2010

The effects of grape seeds extract and grape peels extract prepared from grape pomace on the activity of antioxidant enzymes, degree of lipid peroxidation in serum and liver tissue were investigated in rabbits fed on high cholesterol diet. New Zealand white rabbits were divided as follows ; 1) NOR (normal group); 2) CHOL (cholesterol group); 3) GSH (cholesterol + grape seed extract group); 4) GPE (cholesterol + grape peel extract); 5) GSP (cholesterol + grape seed powder); 6) GPP (cholesterol + grape peel powder); 7) GE (cholesterol + grape seed and peel extract); 8) GP (cholesterol + grape seed and peel powder). Eight groups of rabbits were studied for 8 weeks. At the end of the experimental period, rabbits were sacrificed and the liver tissue were removed. Then, GSH, GPx, GST, CAT and MDA in the liver were measured. In liver tissues, total glutathione contents (GSH), glutathione peroxidase (GPx) and catalase (CAT) activity, which was significantly higher by grape seed extract supplementation. The level of malondialdehyde (MDA) was lower in the serum of rabbits fed grape seed extract or grape peel powder plus cholesterol than in the serum of rabbits fed cholesterol alone. It is therefore likely that grape seed extract prepared from grape pomace functioned as antioxidants in vivo, negating the effects of the oxidative stress induced by 1% cholesterol diet. The grape seed extract was found effective in converting the oxidized glutathione into reduced glutathione, and in removing $H_2O_2$ that is created by oxidative stress. The grape peel powder was found to have small influence on reduced glutathione content, CAT and GPX activity, but it increased GST activity in liver tissues, resulting in promoting the combination of lipid peroxide and glutathione (GSH), and further, lowering the formation of lipid peroxide in the serum. Therefore, grape pomace (grape seed extract and grape peel powder) supplementation is considered to activate the antioxidant enzyme system and prevent damage with hypercholesterolemia.

• Journal of Korean Biological Nursing Science
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• v.10 no.1
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• pp.1-10
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• 2008

Purpose: The purpose of this study was to investigate the cerebral infarction size, antioxidant enzyme activities and lipid peroxidation changes after 6 weeks of dietary soybean protein intake in a rat focal brain ischemia model. Method: Weaning Sprague-Dawley rats were fed with either modified AIN-93G diet containing casein 20% (control), 20% soybean protein isolate-based diet (S20), or 40% of soybean protein isolate-based diet (S40) for 6 weeks. The animals were subject to right middle cerebral artery occlusion for 2 hr. After 24 hr of recirculation, the rats were sacrificed. Antioxidant enzymes activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and thiobarbituric acid reactive substance (TBARS) level in the right brain were also measured. Result: There were no significant differences in the right cortical infarction volume, TBARS level, SOD and CAT activities among the three groups whereas the GPx activities of the S20 group were significantly higher than those of the control group (p=.02). Conclusion: Our results suggest that 20% of soybean protein may have a modulating effect on GPx and possibly have some protective effect against oxidative stress although it may enough to decrease cerebral infarction volume in rat focal brain ischemia model.