• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.146-146
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• 2002

• Toxicological Research
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• v.17 no.4
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• pp.249-253
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• 2001

Fumonisin B1, a mycotoxin, is thought to induce esophageal cancer in humans and apoptosis in animal cells by inhibiting ceramide synthase. Dumonisin Bl may also generate reactive oxygen species directly or indirectly, leading to DNA damage and lipid peroxidation. In this study, a DNA fragmentation assay, dichlorofluorescein (DCF) analysis, and single cell gel electrophoresis (SCGE) were used to investigate the involvement of cellular free radicals, specifically hydrogen peroxide, in the DNA damaging activity of fumonisin B1. From an in vitro DNA fragmentation assay, E. coli DNA, damage by fumonisin Bl was increased by the addition of superxide dismutase (SOD) and decreased by catalase. SCGE and DCF analysis in vivo showed that the nuclear DNA damage and intracellular free radicals in cultured rat hepatocytes treated with fumonisin B1 were increased with the concentration of fumonisin Bl . DNA damage and free radical generation were inhibited by the addition of catalase. Fumonisin Bl , in the presence of SOD, produces hydrogen peroxide causing oxidative DNA damage and protein malfunction, leading to genotoxicity and cytotoxicity of the toxin.

• Proceedings of the Korean Society of Toxicology Conference
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• 2005.05a
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• pp.125-126
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• 2005

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.133-133
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• 2003

In recent years. attention has focused on the application of the alkaline single cell gel electrophoresis (SCGE or Comet) assay in environmental mutagenesis. To evaluate the suitability of the assay as a monitoring. technique, the DNA damages in liver cells and erythrocytes of carp (Cyprinus carpio) exposed to benzo[${\alpha}$]pyrene (B[${\alpha}$]P) were estimated comparatively with the in vivo Comet assay and the micronucleus test (MNT).(omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.151-151
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• 2003

The ethanol extracts of mixed vegetables (Bioactive V, BV), mixed fruits (Bioactive F, BF) and their liquid formulation (Chungpae Plus(R)) were evaluated for antioxidative and antigenotoxic activity. They were shown to possess the significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and were revealed to show the inhibitory effect of lipid peroxidation as measured by malondialdehyde (MDA) formation.(omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.178.2-178.2
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• 2003

To develope the novel anti-allergic drug, many sophoricoside derivatives were synthesized. Among these derivatives, JSH-II-3, JSH-Ⅵ-3, JSH-Ⅶ-3, and JSH-Ⅷ-3 were selected and subjected to high throughput toxicity screening (HTTS) because they revealed strong IL-5 inhibitory activity and limitation of Quantity. Mouse lymphoma thymidine kinase ($tk^{+/-}$) gene assay(MOLY) and single cell gel electrophoresis (Comet) assay in mammalian cells were used as HTTS tool in our laboratory. (omitted)

• KSBB Journal
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• v.11 no.1
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• pp.37-45
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• 1996

Marine bacterial strain, highly effective agar degrading, was isolated from south sea of Korea and was identified as Pseudomonas sp. This strain was named Halophilic Pseudomonas sp. W7 and accumulated an extracellular agarase which showed a high level of enzyme activity in the presence of agar and agarose. This extracellular agarase was purified by anion-exchange chromatography and gel filtration. Purified agarase showed a single protein band upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis and its molecular weight was estimated to be about 89KDa. The agarase gene was cloned into Escherichia coli JM83 using the plasmid vector pUC19. DNA fragments(3.7, 3.0Kb) of Hind III-digested chromosomal DNA of Pseudomonas sp. W7 was inserted into the Hind III site of pUC19. Selected transformants, E. coli JM83/pSWl 000000and E. coli JM83/pSW3, produced agarase and this agarase was accumulated In the cytoplasmic space.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.2
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• pp.95-100
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• 2004

Ischemic preconditioning (IPC) has been accepted as a heart protection phenomenon against ischemia and reperfusion (I/R) injury. The activation of ATP-sensitive potassium $(K_{ATP})$ channels and the release of myocardial nitric oxide (NO) induced by IPC were demonstrated as the triggers or mediators of IPC. A common action mechanism of NO is a direct or indirect increase in tissue cGMP content. Furthermore, cGMP has also been shown to contribute cardiac protective effect to reduce heart I/R-induced infarction. The present investigation tested the hypothesis that $K_{ATP}$ channels attenuate DNA strand breaks and oxidative damage in an in vitro model of I/R utilizing rat ventricular myocytes. We estimated DNA strand breaks and oxidative damage by mean of single cell gel electrophoresis with endonuclease III cutting sites (comet assay). In the I/R model, the level of DNA damage increased massively. Preconditioning with a single 5-min anoxia, diazoxide $(100\;{\mu}M)$, SNAP $(300\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP) $(100\;{\mu}M)$ followed by 15 min reoxygenation reduced DNA damage level against subsequent 30 min anoxia and 60 min reoxygenation. These protective effects were blocked by the concomitant presence of glibenclamide $(50\;{\mu}M)$, 5-hydroxydecanoate (5-HD) $(100\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer (Rp-8-pCPT-cGMP) $(100\;{\mu}M)$. These results suggest that NO-cGMP-protein kinase G (PKG) pathway contributes to cardioprotective effect of $K_{ATP}$ channels in rat ventricular myocytes.

• Molecular & Cellular Toxicology
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• v.3 no.4
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• pp.299-305
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• 2007

The endocrine disrupting chemical, di (2-ethylhexyl) phthalate (DEHP) is a plasticizer used in polyvinyl chloride products ubiquitous in our daily lives. DEHP has potentially adverse effects on the liver, kidney, lung, heart, reproductive organs and endocrine systems. Many toxicological data on the DEHP toxicity have been stated, but complete protein profiles have not yet been reported. In this study, DEHP-induced oxidative DNA damage in rat lymphocyte was evaluated by Comet assay (single-cell gel electrophoresis) for the first time. Moreover, DEHP-induced protein profile alterations were examined in rat liver by using toxicoproteomic tools. 34 protein spots in the liver were identified to be significantly deregulated by DEHP on the 2-dimensional gel. Among them, 20 spots were up-regulated and 14 spots down-regulated by DEHP.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.60-67
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• 1995

Methanol assimilating yeast, Hansenula sp. MS-364 that has high productivity with methanol as carbon and energy source has been preserved at dept. of Microbiological engineering. Purification and properties of alcohol oxidase (E.C.1.1.3.13: oxygen oxidoreductase) were investigated in the methanol assimilating yeast, Hansenula sp. MS-364. Alcohol oxidase is related to the catalytic reaction that degrades alcohol to aldehyde and peroxide. The methanol oxidizing enzyme was purified by ammonium sulfate precipitation, DEAE-Sephadex A-50 chromatography and gel filtration on Sepharose 6B from cell-free extract. The purified enzyme preparation gave a single band in the sodium dodesyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of the enzyme was calculated to be about 576,000 and molecular weight of subunit was also calculated to be 72,000. The optimal pH and temperature of the enzyme reaction were pH 7.5 and 37$\circ$C, respectively. The enzyme was unstable in acidic pH and higher temperature. The enzyme was not specific for methanol and also oxidized lower primary alcohols. The Km value for methanol was 2.5 mM and that for ethanol was 1.66 mM. The enzyme was heavily inhibited by metal ions such as Hg$^{2+}$, Ag$^{2+}$, Cu$^{2+}$. The high concentration of EDTA and sulfhydryl reagents strongly inhibited the enzyme activity. The component of coenzyme was determined to flavin adenine dinucleotide.