• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.407-412
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• 2006

Bioluminescence single-site immunometric assay for methamphetamine (MA) using the native aequorin, a photoprotein, as a signal generator was developed for the first time. MA is a potent sympathomimetic amine with stimulant effects on the central nervous system. MA abuse induces hallucinations and, thus, may cause a serious social problem. The single-site immunometric MA assay was optimized and its dose-response behavior was examined. The dose-response curve shows that the detection limit is 1.1 ${\times}$ $10^{-10}$ M and a dynamic range is four orders of magnitude with 15 $\mu$g/mL BSA-MA conjugate and 1.0 ${\times}$ $10^{-8}$ M anti-MA antibody-biotin conjugate. In order to evaluate this assay, the structurally similar compounds, amphetamine, ephedrine, norephedrine, benzphetamine and N-4-(aminobutyl)methamphetamine were examined for their crossreactivity. None of these five compounds showed any cross-reactivity. Additionally, an artificial urine solution spiked with MA was analyzed by the MA assay, and the result of the analysis demonstrated the usefulness of the present assay for the determination of MA in urine.

• 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

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.419-424
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• 2014

The pro-apoptotic BCL-2 family protein BID activates BAK and/or BAX, which form oligomeric pores in the mitochondrial outer membrane. This results in the release of cytochrome c into the cytoplasm, initiating the apoptotic cascade. Here, we utilized liposomes encapsulating sulfo-rhodamine at a controlled temperature to improve upon a previously reported assay system with enhanced sensitivity and specificity for measuring membrane permeabilization by BID-dependent BAK activation. BAK activation was inhibited by BCL-$X_L$ protein but not by a mutant protein with impaired anti-apoptotic activity. With the assay system, we screened a chemical library and identified several compounds including trifluoperazine, a mitochondrial apoptosis-induced channel blocker. It inhibited BAK activation by direct binding to BAK and blocking the oligomerization of BAK.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.411-415
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• 1998

In the present study, we were evaluated cytotoxic effects of epigallocatechin gallate in human skin melanoma cells such as HTB-69. The light microscopic study showed morphological changes of the treated cells. Disruptions in cell organelles were determined by colorimetric methods; 3-(4,5-dimethyl thiazol-2-yl)-2,5diphenyl-2H-tetrazolium bromide (MTT) assay, neutral red (NR) assay and sulforhodamine B protein (SRB) assay. These results suggest that epigallocatechin gallate retains a potential antitumor activity.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.2
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• pp.183-190
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• 2014

This project's aim was to determine the reserpine-induced gastric ulcer preventive effect of polysaccharide of Larimichthys crocea swim bladder (PLCSB) in ICR mice. The anti-gastric ulcer effects of polysaccharide of Larimichthys crocea swim bladder was evaluated in mice model using morphological test, serum levels assay, cytokine levels assay, tissue contents analysis, reverse transcription-polymerase chain reaction (RT-PCR) analysis and western bolt assay. High concentration (50 mg/kg dose) of PLCSB reduced IFN-${\gamma}$ as compared to low concentration (25 mg/kg dose) and control mice. SS and VIP serum levels of PLCSB treated mice were higher than those of control mice, and MOT and SP serum levels were lower than control mice. Gastric ulcer inhibitory index of PLCSB treatment groups mice were much lower than control mice, and the high concentration treated mice were similar to the ranitidine treated mice. The SOD and GSH-Px activities of PLCSB treated mice were higher than control mice, close to normal mice and ranitidine treated mice. PLCSB treated mice also showed the similar contents of NO and MDA to normal group. By RT-PCR and western blot assay, PLCSB significantly induced inflammation in tissues of mice by downregulating NF-${\kappa}B$, iNOS, and COX-2, and upregulating $I{\kappa}B-{\alpha}$. These results suggest that PLCSB showed a good gastric ulcer preventive effect as the gastric ulcer drug of ranitidine. Polysaccharide of Larimichthys crocea swim bladder may be used as a drug material from marine products.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.125-129
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• 2000

A rapid and efficient assay to determine melanin biosynthesis inhibition of Magnaporthe grisea, a causal agent of the rice blast, by chemicals was developed. Wells in 24-well plates were loaded with spore suspension of the fungus and three known melanin biosynthesis inhibitors of KC10017, tricyclazole, and carpropamid. Subsequent color changes of mycelia and culture media in the wells were observed 7 days after incubation. The wells treated with KC10017 (an inhibitor of polyketide synthesis step and/or pentaketide cyclization step) became colorless, whereas tricyclazole (an inhibitor of 1, 3, 8-trihydroxynaphthalene reductase) or carpropamid (an inhibitor of scytalone dehydratase)-treated wells exhibited red color. They did not show any inhibitory effect on fungal growth. The inhibition of reaction steps prior to 1, 3, 6, 8-tetrahydroxynaphthalene formation was easily determined by colorless medium and mycelia. However, it was impossible to distinguish between inhibition of reduction steps and inhibition of dehydration steps by colors of the cultures. It was accomplished through HPLC analysis of the melanin biosynthesis-involving pentaketide metabolites accumulated by the inhibitors. Through screening of a number of synthetic chemicals using the in vitro assay, we could find a novel chemical group of melanin biosynthesis inhibitor.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1933-1938
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• 2014

Despite increasing importance of in vitro cell-based assays for the assessment of nanoparticles (NPs) cytotoxicity, their suitability for the assessment of NPs toxicity is still in doubt. Here, limitations of widely used cell viability assay protocol (i.e., MTT asssay) for the cytotoxicity assessment of P25 $TiO_2$ NPs were carefully examined and an alternative toxicity assessment method to overcome these limitations was proposed, where the artifacts caused by extracellularly formed formazan and light scattered by agglomerated NPs were minimized by measuring only the intracellular formazan via image cytometric methods.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.605-609
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• 2002

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for the quantitative detection of organophosphorus insecticide cyanophos. An analogue (hapten) of cyanophos was synthesized and was coupled to BSA to produce polyclonal antibodi es from rabbits. The antisera were screened against another hapten coupled to ovalbumin (OVA). Using the sera of highest specificity, an antigen-coated ELISA was developed, which showed an I50 of 310 ng/mL with the detection limit of 20 ng/mL. The antibodies showed negligible cross-reactivities with other organophosphorus pesticides except for parathion-methyl, which makes the assay suitable for the selective detection of cyanophos.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.544-547
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• 2014

In this study, an enzyme-linked immunosorbent assay (ELISA) and immuno-chromatographic technique were combined to fabricate immuno-strip sensors for the detection of Legionella pneumophila. The immuno-strip sensor was manufactured with four different membranes. A nitrocellulose membrane was used to immobilize capture antibody and generate signals due to the high affinity to antibodies, and glass fiber membranes were used as a conjugate release pad and a sample application pad. A cellulose membrane was used as an absorption pad to induce sample flow by the capillarity. Colorimetric signals produced by sandwich immuno-reaction and enzyme reaction could be analyzed qualitatively and quantitatively within 30 min. Under the given experimental conditions, sensor signals with L. pneumophila samples were observed qualitatively by naked eyes and measured quantitatively in a range of $1.3{\times}10^3-1.3{\times}10^6CFU/mL$ with a digital camera and home-made image analysis software.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.211-217
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• 2008

To clarify the DNA damage from reactive oxygen species, we measured the DNA damage through Fpg/Endo III FLARE (Fragment Length Analysis with Repair Enzyme) assay and real time RT-PCR. The 80 SD rats assigned to 4 dose groups exposed to cumene vapor for 90 days. With Fpg/Endo III FLARE assay in hepatocytes, we found the OTM (Olive Tail Moment) and TL (Tail Length) significantly increased in no-enzyme treated and Fpg-treated control and 8 ppm groups with 28 days exposure. In Endo III-treated 8 ppm group, significantly increased the values with 90 days exposure. With lymphocytes, it was founded the values significantly increased in no-enzyme treated 800 ppm group in 28 and 90 days. It was significantly increased in Endo III-treated 80 ppm for 28 days and 800 ppm for 90 days. From the above findings, FLARE assay was suggested as being available as a biological marker for DNA damage induced by cumene exposure in SD rats. And we used real time RT-PCR for the OGG1 mRNA expression, it had dose-dependent biologic effects in 1 day exposure, but decrease the levels of rOGG1 mRNA. Our findings provide evidence that cumene exposure may cause suppression of rOGG1 in the rat hepatocytes or lymphocytes.