• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.69-75
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• 2002

Sterols play two major roles in plants: a bulk component in biological membranes and precursors of plant steroid hormones. Physiological effects of plant steroids, brassinosteroids (BRs), include cell elongation, cell division, stress tolerance, and senescence acceleration. Arabidopsis mutants that carry genetic defects in BR biosynthesis or its signaling display characteristic phenotypes, such as short robust inflorescences, dark-green round leaves, and sterility. Currently there are more than 100 dwarf mutants representing 7 genetic loci in Arabidopsis. Mutants of 6 loci, dwf1/dim1/cbb1, cpd/dwf3, dwf4, dwf5, det2/dwf6, dwf7 are rescued by exogenous application of BRs, whereas bri1/dwf2 shares phenotypes with the above 6 loci but are resistant to BRs. These suggest that the 6 loci are defective in BR biosynthesis, and the one locus is in BR signaling. Biochemical analyses, such as intermediate feeding tests, examining the levels of endogenous BR, and molecular cloning of the genes revealed that dwf7, dwf5, and dwf1 are defective in the three consecutive steps of sterol biosynthesis, from episterol to campesterol via 5-dehydroepisterol. Similarly, det2/dwf6, dwf4, and cpd/dwf3 were Shown to be blocked in $D^4$ reduction, 22a-hydroxylation, and 23 a-hydroxylation, respectively. A signaling mutant bri1/dwf2 carries mutations in a Leucine-rich repeat receptor kinase. Interestingly, the bri1 mutant was shown to accumulate significant amount of BRs, suggesting that signaling and biosynthesis are dynamically coupled in Arabidopsis. Thus it is likely that transgenic plants over-expressing the rate-limiting step enzyme DWF4 as well as blocking its use by BRI1 could dramatically increase the biosynthetic yield of BRs. When applied industrially, BRs will boost new sector of plant biotechnology because of its potential use as a precursor of human steroid hormones, a novel lead compound for cholesterol-lowering effects, and a various application in plant protection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1045-1052
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• 2017

In this study, a battery of genetic-toxicity studies on corn silk extract with high maysin content were performed according to internationally accepted protocols. In a mutation test using Salmonella Typhimurium TA1535, TA1537, TA98, and TA100, the number of mutant colonies did not significantly increase up to a maximum concentration of $5,000{\mu}g/plate$ in the presence or absence of the S9 metabolic activation system. In the chromosome aberration test using Chinese hamster lung fibroblasts, negative results were observed in the concentration up to $1,250{\mu}g/mL$ of corn silk extract. In the micronucleus test using ICR mice, incidence of polymorphonuclear erythrocytes with a maximum concentration of 2,000 mg/kg corn silk extract did not show any significant difference compared to the negative control group. Based on these results, the test substance, con silk extract, did not influence genotoxicity.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.151-159
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• 2005

Injury caused by reactive oxygen species (ROS), known as oxidative stress, is one of the major damaging factors in plants exposed to environmental stress. Chloroplasts are specially sensitive to damage by ROS because electrons that escape from the photosynthetic electron transfer system are able to react with relatively high concentration of $O_2$ in chloroplasts. To cope with oxidative stress, plants have evolved an efficient ROS-scavenging enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), and low molecular weight antioxidants including ascorbate, glutathione and phenolic compounds. To maintain the productivity of plants under the stress condition, it is possible to fortify the antioxidative mechanisms in the chloroplasts by manipulating the antioxidation genes. A powerful gene expression system with an appropriate promoter is key requisite for excellent stress-tolerant plants. We developed a strong oxidative stress-inducible peroxidase (SWPA2) promoter from cultured cells of sweetpotato (Ipomoea batatas) as an industrial platform technology to develop transgenic plants with enhanced tolerance to environmental stress. Recently, in order to develop transgenic sweetpotato (tv. Yulmi) and potato (Solanum tuberosum L. cv. Atlantic and Superior) plants with enhanced tolerance to multiple stress, the genes of both CuZnSOD and APX were expressed in chloroplasts under the control of an SWPA2 promoter (referred to SSA plants). As expected, SSA sweetpotato and potato plants showed enhanced tolerance to methyl viologen-mediated oxidative stress. In addition, SSA plants showed enhanced tolerance to multiple stresses such as temperature stress, drought and sulphur dioxide. Our results strongly suggested that the rational manipulation of antioxidative mechanism in chloroplasts will be applicable to the development of all plant species with enhanced tolerance to multiple environmental stresses to contribute in solving the global food and environmental problems in the 21st century.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.139-144
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• 2002

Sterols play two major roles in plants: a bulk component in biological membranes and precursors of plant steroid hormones. Physiological effects of plant steroids, brassinosteroids (BRs), include cell elongation, cell division, stress tolerance, and senescence acceleration. Arabidopsis mutants that carry genetic defects in BR biosynthesis or its signaling display characteristic phenotypes, such as short robust inflorescences, dark-green round leaves, and sterility. Currently there are more than 100 dwarf mutants representing 7 genetic loci in Arabidopsis. Mutants of 6 loci, dwf1/dim1/cbb1, cpd/dwf3, dwf4, dwf5, det2/dwf6, dwf7 are rescued by exogenous application of BRs, whereas bri1/dwf2 shares phenotypes with the above 6 loci but are resistant to BRs. These suggest that the 6 loci are defective in BR biosynthesis, and the one locus is in BR signaling. Biochemical analyses, such as intermediate feeding tests, examining the levels of endogenous BR, and molecular cloning of the genes revealed that dwf7, dwf5, and dwf1 are defective in the three consecutive steps of sterol biosynthesis, from episterol to campesterol via 5-dehydroepisterol. Similarly, det2/dwf6, dwf4, and cpd /dwf3 were shown to be blocked in D$^4$reduction, 22a-hydroxylation, and 23 a-hydroxylation, respectively. A signaling mutant bril/dwf2 carries mutations in a Leucine-rich repeat receptor kinase. Interestingly, the bri1 mutant was shown to accumulate significant amount of BRs, suggesting that signaling and biosynthesis are dynamically coupled in Arabidopsis. Thus it is likely that transgenic plants over-expressing the rate-limiting step enzyme DWF4 as well as blocking its use by BRIl could dramatically increase the biosynthetic yield of BRs. When applied industrially, BRs will boost new sector of plant biotechnology because of its potential use as a precursor of human steroid hormones, a novel lead compound for cholesterol-lowering effects, and a various application in plant protection.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.265-278
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• 2011

Objectives : This trial were conducted to evaluate the efficacy and adverse events of Bofutsusho-san(BTS) and Boiogiot-tang(BOT) by oriental obesity pattern identification on obese subjects, as compared to placebo. Methods : 166 subjects(body mass index ${\geq}25kg/m^2$) were recruited and randomized to receive BT(n=55), FH(n=55) or placebo(n=56) for 8 weeks. Anthropometric factors, serum lipid, glucose, blood pressure(BP), pulse rate, resting metabolic rate and oriental obesity pattern identification questionnaire were measured at baseline and 8 weeks. Adverse events and safety outcome variables were also checked during trials. Results : The frequency of top-scored oriental obesity pattern was ordered by indigestion(食積) > stagnation of the liver qi(肝鬱) > yang deficiency(陽虛) > spleen deficiency(脾虛) > phlegm(痰飮) > blood stasis(瘀血) in subjects. BTS group significantly decreased body weight, body mass index(BMI), waist circumference(WC), body fat mass, total cholesterol and HDL-cholesterol in stagnation of the liver qi(肝鬱) and WC in indigestion(食積). BOT group showed significant decrease of body weight, BMI, WC, and body fat mass in indigestion(食積) not in deficiency(虛症). Adverse events were reported most frequently in yang deficiency(陽虛) by BT group and stagnation of the liver qi(肝鬱) by BOT group. Conclusions : Bofu-tsusho-san was effective in treating obesity with stagnation of the liver qi(肝鬱). Obesity pattern identification could be a useful diagnostic tool predicting treatment effects and adverse events.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.14-14
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• 2010

Vitamin C (ascorbic acid) is an essential component for collagen biosynthesis and also for the proper functioning of the cardiovascular system in humans. Unlike most of the animals, humans lack the ability to synthesize ascorbic acid on their own due to a mutation in the gene encoding the last enzyme of ascorbate biosynthesis. As a result, vitamin C must be obtained from dietary sources like plants. In this study, we have developed two different kinds of transgenic potato plants (Solanumtuberosum L. cv. Taedong Valley) overexpressing strawberry GalUR and mouse GLoase gene under the control of CaMV 35S promoter with increased ascorbic acid levels. Integration of the these genes in the plant genome was confirmed by PCR and Southern blotting. Ascorbic acid(AsA) levels in transgenic tubers were determined by high-performance liquid chromatography(HPLC). The over-expression of these genes resulted in 2-4 folds increase in AsA intransgenic potato and the levels of AsA were positively correlated with increased geneactivity. The transgenic lines with enhanced vitamin C content showed enhanced tolerance to abiotic stresses induced by methyl viologen(MV), NaCl or mannitol as compared to untransformed control plants. The leaf disc senescence assay showed better tolerance in transgenic lines by retaining higher chlorophyll as compared to the untransformed control plants. Present study demonstrated that the over-expression of these gene enhanced the level of AsA in potato tubers and these transgenics performed better under different abiotic stresses as compared to untransformed control. We have also investigated the mechanism of the abiotic stress tolerance upon enhancing the level of the ascorbate in transgenic potato. The transgenic potato plants overexpressing GalUR gene with enhanced accumulation of ascorbate were investigated to analyze the antioxidants activity of enzymes involved in the ascorbate-glutathione cycle and their tolerance mechanism against different abiotic stresses under invitro conditions. Transformed potato tubers subjected to various abiotic stresses induced by methyl viologen, sodium chloride and zinc chloride showed significant increase in the activities of superoxide dismutase(SOD, EC 1.15.1.1), catalase, enzymes of ascorbate-glutathione cycle enzymes such as ascorbate peroxidase(APX, EC 1.11.1.11), dehydroascorbate reductase(DHAR, EC 1.8.5.1), and glutathione reductase(GR, EC 1.8.1.7) as well as the levels of ascorbate, GSH and proline when compared to the untransformed tubers. The increased enzyme activities correlated with their mRNA transcript accumulation in the stressed transgenic tubers. Pronounced differences in redox status were also observed in stressed transgenic potato tubers that showed more tolerance to abiotic stresses when compared to untransformed tubers. From the present study, it is evident that improved to lerance against abiotic stresses in transgenic tubers is due to the increased activity of enzymes involved in the antioxidant system together with enhanced ascorbate accumulated in transformed tubers when compared to untransformed tubers. At moment we also investigating the role of enhanced reduced glutathione level for the maintenance of the methylglyoxal level as it is evident that methylglyoxal is a potent cytotoxic compound produced under the abiotic stress and the maintenance of the methylglyoxal level is important to survive the plant under stress conditions.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.28-32
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• 1988

Recently, we isolated a toxic substance named 'toxohormone-L' from ascites fluid of patients with various malignant tumors. The toxohormone-L stimulated lipolysis in rat adipocytes and induced anorexia in rats. Both the lipolytic and the anorexigenic actions of toxohormone-L were found to be inhibited by ginsenoside $Rb_2$ in Korean red ginseng. Isolated rat adipocytes are well known to possess opposite pathways of lipid metabolism: lipolysis and lipogenesis. Both of the metabolism respond to various biologically active substances such as epinephrine, ACTH and insulin. Epinephrine and ACTH stimulate lipolysis and insulin accelerates lipogenesis. Recently. Korean red ginseng powder was found to contain adenosine and an acidic substance which inhibited epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis from added glucose. The chemical structure of this acidic substance is determined to be pyro-glutamic acid (Pyro-Glu), Pyro-Glu exhibits selective modulations toward the opposite metabolic pathways in rat adipocyte; It inhibits the lipolysis but stimulates the lipogenesis. We call these substances (adenosine, Pyro-Glu) 'selective modulators' or 'insulin-like substances'. Based on these results, physiological significances of these substances in Korean red ginseng were discussed.

• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.17-23
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• 2002

In order to investigate effects if loess on the mycellial pellet formation a phosphate-solubilizing fungus. Aspergillus sp. PS-104 was cultured in potato dextrose broth containing loess. The strain formed an amorphous pellet or loose aggregates agitated at a low speed (50 rpm) while spherical and regular pellets at a high speed (150 rpm) The higher concentration of loess was added, the smaller size of a pellet was formed during the submerged culture of the strain. As shown in results, being cultured in the PDB medium supplemented with 1.0% loess the pellet size was maximally reduced to a fourth compared to the control. Evaluating the addition effect of several components of loess such as $SiO_2$, $Fe_2O_3$, $Al_2O_3$, $CaCO_3$, $CaSO_4$ and $MgCO_3$ on the reduction of mycellial pellet size the higher concentration was supplied, the smaller size of pellet was formed except $Al_2O_3$. And the smallest pellet size was recorded at the concentration of 1.0% (W/V) magnesium carbonate.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.459-466
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• 2016

Adipogenic differentiation of mesenchymal stem cells (MSCs) is critical for metabolic homeostasis and nutrient signaling during development. However, limited information is available on the pivotal modulators of adipogenic differentiation of MSCs. Adaptor protein Lnk (Src homology 2B3 [SH2B3]), which belongs to a family of SH2-containing proteins, modulates the bioactivities of different stem cells, including hematopoietic stem cells and endothelial progenitor cells. In this study, we investigated whether an interaction between insulin-like growth factor-1 receptor (IGF-1R) and Lnk regulated IGF-1-induced adipogenic differentiation of MSCs. We found that wild-type MSCs showed greater adipogenic differentiation potential than $Lnk^{-/-}$ MSCs. An ex vivo adipogenic differentiation assay showed that $Lnk^{-/-}$ MSCs had decreased adipogenic differentiation potential compared with wild-type MSCs. Interestingly, we found that Lnk formed a complex with IGF-1R and that IGF-1 induced the dissociation of this complex. In addition, we observed that IGF-1-induced increase in the phosphorylation of Akt and mammalian target of rapamycin was triggered by the dissociation of the IGF-1R-Lnk complex. Expression levels of a pivotal transcription factor peroxisome proliferator-activated receptor gamma ($PPAR-{\gamma}$) and its adipogenic target genes (LPL and FABP4) significantly decreased in $Lnk^{-/-}$ MSCs. These results suggested that Lnk adaptor protein regulated the adipogenesis of MSCs through the $IGF-1/Akt/PPAR-{\gamma}$ pathway.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.257-266
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• 2002

To estimate the nitrogen budget and assess the purification function of a tidal flat ecosystem, a field survey was carried out at Hajeon tidal flat in Gomso Bay, the southern part of Byeonsan Peninsula, Chollabuk-do, Korea. A study area of 3.0$\times$4.5 ㎢ was established on the tidal flat and the concentrations of chlorophyll-a, DIN, DON, and TN were measured in the water column during the period of April 17-18, 1999: From the budget analysis, the loss rate of Chl-a was estimated to be -0.05 mg Chl/㎡/hr, which is approximately 7% of that at Issiki tidal flat in Aichi Prefecture, Japan. The lower loss rate of Chl-a in the study area was attributable to the lower standing crop of phytoplankton, the lower temperature that may reduce metabolic rates of biotic components and the lower biomass of macrobenthos in the study area. Over the 13.5 ㎢ of study area, Hajeon tidal flat removed 8.36$\times$10$\^$2/ kg N/day of TN, 5.36$\times$10$\^$3/ kg N/day of PON and 1.62$\times$10$\^$2/ kg N/day of phytoplankton-related PON, showing that the tidal flats may play an important role in removing nitrogen in coastal waters. The removal rate of PON, compared to the removal cost of the existing waste water treatment facilities, indicates that the economic value of the purification function of Hajeon tidal flat (13.5㎢) may be more than that of two large facilities.