• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.598-599
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• 2006

• Proceedings of the Korean Society of Crop Science Conference
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• 2006.04a
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• pp.554-555
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• 2006

• 한국약용작물학회:학술대회논문집
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• 2008.05a
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• pp.264-265
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• 2008

• 한국약용작물학회:학술대회논문집
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• 2008.05a
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• pp.267-268
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• 2008

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.64-72
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• 2007

Iron is an important micronutrient for plants. Iron metabolism is a complex mechanism under a delicate balance. Iron metabolism represents two major problems for plants: deficiency as a consequence of solubility problems and toxicity due to excess solubility in anaerobic conditions. In the last few years, new genes have been discovered that influence iron uptake, transport and storage. Irrigated rice is exposed to high levels of $Fe^{II}$, normally rare in aerobic soil conditions. The implications of altering iron uptake rates and the effects of newly discovered genes are discussed.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.65-70
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• 2005

A growing body of evidence shows that nitric oxide $({\cdot}NO)$ and ${\cdot}NO-derived$ reactive nitrogen species (RNS) act as both plant physiological regulators and stressors. However, very little is known concerning metabolism of RNS in plant cells. In this paper, we explore a plant metabolic basis for RNS, with special emphasis on the possible relationship to nitrogen assimilation, and discuss the potential of the metabolic engineering for plant-biotechnological application.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.573-577
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• 2008

$^1H$-Nuclear magnetic resonance (NMR) spectrometry was applied to the quantitative analysis of coumarins in the roots of Angelica gigas without any chromatographic purification. The experiment was performed by the analysis of each singlet germinal methyl, which was well separated in the range of 1.0-2.0 ppm in the $^1H$-NMR spectrum. The quantity of the compounds was calculated by the ratio of the intensity of each compound to the known amount of internal standard (dimethyl terephthalate). These results were compared with the conventional gas chromatography (GC) method. The contents of decursin and decursinol angelate in A. gigas were determined $1.98{\pm}0.07$, $1.13{\pm}0.08%$ in quantitative $^1H$-NMR method and $2.06{\pm}0.24$, $1.17{\pm}0.24%$ in GC method, respectively. The advantages of quantitative $^1H$-NMR analysis are that can be analyzed to identify and quantify, and no reference compounds required for calibration curves. Besides, it allows rapid and simple quantification for coumarins with an analysis time for only 10 min without any preprocessing.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.233-237
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• 2007

The roots of Brassica campestris ssp rapa were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_{2}O$. From the EtOAc and n-BuOH fractions, five compounds were isolated through the repeated silica gel column chromatographies. From the result of spectroscopic data including NMR and MS, the chemical structures of the compounds were determined as palmitic acid methyl ester (1), linolenic acid methyl ester (2), linoleic acid methyl ester (3), ${\beta}-sitosterol$ (4) and daucosterol (5).

• Applied Biological Chemistry
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• v.48 no.3
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• pp.263-266
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• 2005

Cymbidium goeringii REICHB. fil was extracted with 80% MeOH and solvent-fractionated with EtOAc, n-BuOH and $H_2O$, successively. From EtOAc fraction, three sterols were isolated on repeated silica gel and ODS column chromatographies. The chemical structures were determined as ${\beta}-sitosterol$ (1), daucosterol (2) and ergosterol peroxide (3) by NMR, MS and IR, which is the first to be isolated from Cymbidium goeringii REICHB. fil.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.728-732
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• 2000

Propagation of Anagrapha falcifera nuclear polyhedrosis virus(AfNPV) was investigated using well-plates and split-flow air-lift bioreactors. In well-plate experiments, the effects of pH, cell density at a point of infection, serum concentration, DEAE-dextran, and lipid on virus propagation were all closely examined. The AfNPV titer in well-plates was optimal at pH 6.8 and $3{\times}10^6$ cells/$cm^2$. The virus titer was not dramatically affected when the fetal bovine serum concentration was reduced from 10% to 5%. The addition of cholesterol at AfNPV infection of Sf21 cells enhanced the virus titer, whereas the addition of DEAE-dextran did not improve the titer. The AfNPV titer ($3.8{\times}10^7$ $TCID_{50}/ml$) at optimized conditions for well-plate experiments was 2.5-fold higher than for the control. In bioreactor experiments, the AfNPV titer showed its maximum level at air flow rates of 20-40 ml/min. In a split-flow air-lift bioreactor, AfNPV titer ($2.3{\times}10^7\;TCID_{50}/ml$) was 1.5-fold higher than the control when the culture was at pH 6.8 and supplemented with 0.34 mM cholesterol.