• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.113-113
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• 2002

The stimulatory effect of EGF and FSH on oocyte maturation have been reported in various mammalian species. And some reports presented FSH enhanced the effect of EGF on oocyte maturation. But, the interaction between EGF and FSH on nuclear maturation of mammalian oocytes is not fully understood. We observed the effect of EGF and FSH on nuclear maturation during in vitro maturation of mouse oocytes. Also, we examined the interaction between EGF and FSH on nuclear maturation of mouse oocytes using the EGFR inhibitor or FSH inhibitor. Germinal vesicle (GV) stage oocytes were obtained from 3-4weeks PMSG primed BCFI hybrid mice and cultured in TCM-199 medium with 0.4%PVP supplemented with/without EGF (1ng/ml), FSH (1ug/ml), EGFR specific tyrosine kinase inhibitors: Tyrphostin AG 1478 (500nM), MAP kinase kinase inhibitor : U0126 (20uM) or PD 98059 (100uM) for 14-l5hr. Rapid staining method were used for the assessment of nuclear maturation. Nuclear maturation rates of EGF indjor FSH-treated group were significantly higher than those of control group. Treatment of EGFR inhibitor significantly block the nuclear maturation of GV oocyte in EGF-treated group, but it did not block those of GV oocyte in FSH-treated or FSH and EGF-treated group. Treatment of FSH inhibitor(U0126, PD98059) significantly block the nuclear maturation of EGF-treated group, FSH-treated and FSH and EGF-treated group. These results show that EGF has a stimulatory effect as well as different action pathway with FSH on in-vitro maturation of mouse oocyte in vitro. Therefore, further studies will be needed to find the signaling pathway of EGF associated with nuclear maturation.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.664-670
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• 1998

The role of intracellular $Ca^{2+}$, in the regulation of tumor cell proliferation by products of arachidonic acid (AA) metabolism was investigated using U-373 MG human as trocytoma cells. Treatment with nordihydroguaiaretic acid (NDGA), a lipoxygenase (LOX) inhibitor, or caffeic acid (CA), a specific 5-LOX inhibitor, suppressed proliferation of the tumor cells in a dose-dependent manner. However, indomethacin (indo), a cyclooxygenase (COX) inhibitor, did not significantly alter proliferation of the tumor cells. At anti-proliferative concentrations, NDGA and CA significantly inhibited intracellular $Ca^{2+}$ release induced by carbachol, a known intracelluar $Ca^{2+}$ agonist in the tumor cells. Exogenous administration of leukotriene $B_4(LTB_4)$, an AA metabolite of LOX pathway, enhanced proliferation of the tumor cells in a concentration-dependent fashion. In addition, $LTB_4$, induced intracelluar $Ca^{2+}$ release. Intracellular $Ca^{2+}$-inhibitors, such as an intracellular $Ca^{2+}$ chelator (BAPTA) and intracellular $Ca^{2+}$-release inhibitors (dantrolene and TMB-8), significantly blocked the LTB4-induced enhancement of cell proliferation and intracellular $Ca^{2+}$ release. These results suggest that LOX activity may be critical for cell proliferation of the human astrocytoma cells and that intracelluar $Ca^{2+}$ may play a major role in the mechanism of action of LOX.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.707-713
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• 2000

Myasthenia gravis (MG) is caused mainly by autoantibodies directed against acetylcholine receptors located in the postsynaptic muscle cell membrane. Using in vitro selection techniques, we isolated an RNA containing 2'-fluoro pyrimidines that can specifically and avidly ($K_d$ ~25 nM) bind rat monoclonal antibody called mAb198, which recognizes the main immunogenic region on the acetylcholine receptors. This RNA can act as a very effective decoy and block mAb198 binding to the receptors in vitro. Furthermore, this RNA decoy can prevent the antigenic modulation of the acetylcholine receptor caused by mAb198 in human muscle cell cultures with and $IC_{50} $of approximately $2.4{\mu}M$. These results indicate that the RNA selected in this study is a more potent decly inhibitor of myashthenic antibodies than the previously identified RNA with 2'-amino pyrimidines [11]. Moreover, this RNA cross-reacts with autoantibodies from patients with MG and can protect human cells from the effects of these antibodies. These observations have important implications for developing an antigen-specific treatment of autoimmune diseases including MG, which is based on decoy RNAs selected in vitro.

• Korean Journal of Pharmacognosy
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• v.27 no.2
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• pp.91-95
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• 1996

In the course of searching for acetylcholinesterase inhibitors from crude drugs, it was found that total MeOH extract of Corydalis Tuber showed significant inhibitory effect on acetylcholinesterase. To isolate acetylcholinesterase inhibitors from Corydalis Tuber, total MeOH extract of the the crude drug was subjected to activity guided fractionation. The MeOH extract was suspended in water and fractionated with methylene chloride and subjected to acid-base fractionation. Silica gel column chromatography of the basic fraction which showed significant inhibitory effect on acetylcholinesterase was carried out and 5 subfractions (1-5) were obtained. From subtraction 4, compound I was isolated. The structure of isolated compound I was identified by spectroscopic parameters of $^1H-NMR$, $^{13}C-NMR$, EI-MS and FAB-MS. The compound I was identified as berberine. It was found from the Lineweaver-Burk plot that berberine was a reversible and specific inhibitor of acetylcholinesterase having 90% inhibitory effect at the concentration of $2.5{\mu}M$.

• The Korean Journal of Food And Nutrition
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• v.22 no.1
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• pp.97-102
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• 2009

In order to obtain a non-toxic and more active and stable microorganism-produced tyrosinase inhibitor, we isolated actinomycetes F-97, a producer of tyrosinase inhibitor, from soil. The aerial hyphae of this strain were gray in color with tree types. Under the microscopic examination, the isolate formed a spiral aerial spore mass with a smooth surface. The analysis of cell wall acid hydrolysate of the isolate revealed the presence of LL-diaminopimelic acid(LL-DAP). No specific sugar was detected. From these results and the cultural and physiological characteristics described in the Bergey's Manual, actinomycetes F-97 was identificated as, or best-matched to, Streptomyces aburaviensis.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.110-113
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• 2006

Prolyl endopeptidase (PEP, EC 3.4.21.26, also referred to as prolyl oligopeptidase) degrades proline containing, biologically active neuropeptides such as vasopressin, substance P and thyrotropin-releasing hormone by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity. Therefore, a specific PEP inhibitor can be a good candidate of drug against memory loss. Upon our examination for PEP inhibitory activity from micronutrients, ascorbic acid (vitamin C) showed small but significant PEP inhibition (13% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$). Palmitic acid showed almost no PEP inhibition. However, 6-O-palmitoyl ascorbic acid ($\underline{1}$) showed 70% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$ indicating that hydrophobic portion of the compound $\underline{1}$ may facilitate the inhibitory effect. $IC_{50}$ value of compound $\underline{1}$ was $12.6{\pm}0.2{\mu}M$. The primary and secondary Lineweaver Burk and Dixon plots for compound $\underline{1}$ indicated that it is a non-competitive inhibitor with inhibition constant (Ki) value of $23.7{\mu}M$.

• Molecules and Cells
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• v.23 no.2
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• pp.138-144
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• 2007

Previously we showed that the human GM3 synthase gene was expressed during the induction of megakaryocytic differentiation in human leukemia K562 cells by phorbol 12-myristate 13-acetate (PMA). In this study we found that treatment of PMA-induced K562 cells with $G{\ddot{o}}6976$, a specific inhibitor of PKC, and U0126, an inhibitor of the extracellular signal-regulated kinase (ERK) reduced expression of GM3 synthase, whereas wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K) did not. Moreover, activation of ERK and cAMP response element binding protein (CREB) was prevented by pretreatment with $G{\ddot{o}}6976$ and U0126. PMA stimulated the promoter activity of the 5'-flanking region from -177 to -83 region of the GM3 synthase gene, and mutation or deletion of a CREB site located around -143 of the promoter reduced PMA-stimulated promoter activity, as did the inhibitors $G{\ddot{o}}6976$ and U0126. Our results demonstrate that induction of GM3 synthase during megakaryocytic differentiation in PMA-stimulated human leukemia K562 cells depends upon the PKC/ERK/CREB pathway.

• Archives of Pharmacal Research
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• v.26 no.12
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• pp.1024-1028
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• 2003

A prolyl endopeptidase inhibitor was isolated from the ethyl acetate soluble fraction of Phyllanthus ussurensis. The active compound was identified as an ellagitannin, corilagin. It was shown to non-competitively inhibit prolyl endopeptidase (PEP) with the $IC_{50}$ value of $1.17 \times $10^{-6}\mu$M. The Ki value was $6.70 \times 10^{-7}$ M. Corilagin was less inhibitory to other serine proteases such as chymotrypsin, trypsin, and elastase, indicating that it was relatively a specific inhibitor of PEP. Corilagin also effectively inhibited reactive oxygen species such as hydroxide and superoxide anion radical, hydrogen peroxide, and DPPH. Especially, corilagin showed potent scavel1ging activity on the superoxide anion radical in the ESR method ($IC_{50} =3.79 \times 10^{-6}$M) as well as xanthine oxidase system.

• Development and Reproduction
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• v.14 no.3
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• pp.207-214
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• 2010

The tremendous changes of uterine endometrium are observed during early pregnancy and protease and their inhibitors are involved in regulation of cell proliferation and remodeling of the tissues through remodeling the extracellular matrix (ECM). Some of the proteases and protease inhibitors have been suspected to a factor in endometrial changes but many parts of their expression profiles and the physiological roles are not uncovered. To evaluate the functional roles of them, in this study the expression profiles of proteases and protease inhibitors were analyzed using real-time quantitative PCR analysis. Mmp9 (matrix metalloproteinase 9) mRNA levels peaked on day 4 at the time of implantation. On the other hand, Ela2 (neutrophil elastase, NE) mRNA levels were peaked on day 2 of pregnancy. Its expression were decreased until day 4 of pregnancy but increased rapidly until day 7 of pregnancy and decreased again. NE inhibitor Slpi (secretory leukocyte protease inhibitor, SLPI) mRNA levels were related with the implantation stage and with the levels of Ela2. At the time of implantation the expression levels of Slpi mRNA were about 5 times higher than the Ela2 mRNA in the uterus. In the implantation stage embryos, Mmp9 specific mRNA was only detected at the blastocyst. On the other hand, the expression level of SLPI was higher than that of the Ela2 mRNA at blastocyst and 4.5 day p.c. embryos. Based on these results it is suggested that MMP9, SLPI, and NE have important physiological role in embryo implantation both in uterus and embryos.

• Korean Journal of Crystallography
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• v.18 no.1_2
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• pp.10-15
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• 2007

UDP-N-acetylglucosamine enolpyruvyl transferase (MurA; EC 2.5.1.7) catalyzes the first committed step of peptidoglycan biosynthesis in bacteria, i.e., transfer of enolpyruvate from phosphoenolpyruvate to UDP-N-acetyl-glucosamine. Because the crystallization condition contained a high concentration of ammonium sulfate, our inhibitor binding studies were not successful. Therefore, we employed a docking approach to investigate the inhibitor binding. Our results will be useful in structure-based design of specific inhibitors of MurA for antibacterial discovery.