• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1157-1162
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• 2004

A well-holder type piezoelectric chloramphenicol (CAP) immunosensor which was prepared by binding an anti­CAP antibody to the chemisorbed monolayers of various thiol or sulfide compounds over the gold electrode surface of quartz crystals through a carboxyl-amine coupling procedure, using the activation with l-ethyl- 3-(3-dimethylarninopropyl)carbodiimide­HCl and N-hydroxysulfosuccinimide, was determined for its responses to CAP, CAP succinate, and water-soluble CAP. The reaction phase used in the well holder was 0.01 M phosphate buffer (pH 7.4), and the solvent for analyte dissolution varied according to the solubility of the individual analyte. The analyte detection which was indicated by a steady-state frequency shift was finished within 10 min, except for CAP dissolved in methanol. The responses of CAP succinate and water-soluble CAP in the reaction phase were very stable, while a minute fluctuation was found with CAP.

• Parasites, Hosts and Diseases
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• v.48 no.4
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• pp.281-284
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• 2010

Due to the possible emergence of resistance and safety concerns on certain treatments, development of new drugs against parasites is essential for the effective control and subsequent eradication of parasitic infections. Several drug targets have been identified which are either genes or proteins essential for the parasite survival and distinct from the hosts. These include the phosphagen kinases (PKs) which are enzymes that playa key role in maintenance of homeostasis in cells exhibiting high or variable rates of energy turnover by catalizing the reversible transfer of a phosphate between ATP and naturally occurring guanidine compounds. PKs have been identified in a number of important human and animal parasites and were also shown to be significant in survival and adaptation to stress conditions. The potential of parasite PKs as novel chemotherapeutic targets remains to be explored.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.3
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• pp.144-148
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• 2002

Hydroxyapatite/titanium composites were prepared as 4-layered functionally graded materials (FGM) using a spark plasma sintering (SPS) apparatus. The maximum density and the biaxial strength of hydroxyapatite/titanium composites were achieved by SPS with a holding time 8 minutes at $1200^{\circ}C$. However, the hydroxyapatite was decomposed tetracalcium phosphate (TetCP) at $1100^{\circ}C$, and calcium titanate compounds ($CaTiO_3$) were formed. When titanium was added to hydroxyapatite, decomposition of hydroxyapatite was occurred easily at the low temperature.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.698-706
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• 2004

$\beta$-Lactam antibiotics such as penicillin G, amoxicillin, and ampicillin were determined by a potentiometric biosensor system which exploited penicillinase immobilized on Immobilon cellulose nitrate membrane and a flat-bottomed pH electrode-as the biological component and transducer. The optimum reaction buffer for maximum sensitivity was found as 2 mM of sodium phosphate buffer (pH 7.2). The detection limit of the biosensor could be extended to 1 $\mu{M}$ of the analytes by increasing the enzyme loading for immobilization to 100 units/$m\ell$. The model samples spiked with each of the standard penicillins were measured for their biosensor responses and HPLC peak area, resulting in the relative responses of 82.1-103.5% and 79.5-106.1% for the biosensor method along with HPLC analysis, respectively. This result showed a good precision of the current biosensor method for screening the penicillin compounds.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.213-216
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• 1996

Optically active carboxylic acid, D-(-)-$\beta$-hydroxyisobutyric acid {(D)-(-)-HIBA} is a useful chiral starting material for the preparation of enantiomerically pure bioactive compounds which have a chiral methyl carbon center in the molecule such as captopril, $\alpha$-tocopherol, erythromycin A, muscone and so on. (S)-3-Acetoxy-2-methylpropanol can be used as the precursor of (D)-(-)-HIBA, that is, chemical oxidation of the hydroxyl group and subsequent hydrolysis of acyl group in (S)-3-acetoxy-2-methylpropanol affords D-(-)-$\beta$-hydroxyisobutyric acid. (S)-3-Acetoxy-2-methyl-propanol was prepared by lipase-catalyzed asymmetric hydrolysis. In the enzymatic hydrolysis system, lipase AY (Candida rugosa) provided the expected (S)-3-acetoxy-2-methylpropanol in 60% e.e. of the enantiomeric purity under the phosphate buffer and organic co-solvent system.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.429-436
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• 1999

A simple, accurate and reproducible Capillary electrophoresis (CE) assay has been developed for the determination of baicalin, baicalein, wogonin and chrysin in Scutellaria baicalensis. Successful separation of these compounds has been obtained in 35 mM phosphate butter (pH 7.0) using a untreated fused silica capillary ($57{\;}cm{\times}75{\;}{\mutextrm{m}}$ i.d.) at $25^{\circ}C$ with the electric field of 19kV. Baicalin, baicalein wogonin and chrysin was separated and detected at 280 nm 13 min. The detection limits of CE were acceptable compared to HPLC. Reproducibilities of migration time and peak area were 0.66~1.11% (within-run), 2.18~3.38% (between-run) and 3.50~4.55% (within-run), 3.97~4.82%(between-run) at CE. The results indicate that CE could be a promising technique for quality and quantity control analysis of Scutellaria baicalensis as a validation method.

• Journal of Ginseng Research
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• v.17 no.3
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• pp.246-249
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• 1993

Hexane, Hexane/diethylether and chloroform fractions from Panax ginseng C.A. Meyer stroungly inhibitied human platelet aggregation induced by a high dose of thrombin (2$\mu$/ml). Chloroform fraction more strongly inhibited the platelet aggregation than the other two fraction among them. There were fatty acid ester and phosphate ester instead of polyacethylene compounds in the chloroform fraction.

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.5-21
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• 1998

The purpose of this paper is to show that X-ray absorption spectroscopy (XANES and EXAFS) is a powerful technique for characterizing both crystalline and amorphous solids from structural (local order) and electronic point of view. The principle of this technique is briefly described by showing the main factors which must be considered for recording and fitting the experimental results. Some non-trivial examples have been selected for demonstrating that XAS spectroscopy is the only technique for bringing a definitive answer as for example: the determination of the local distortion of the $NiO_6$ octahedra in the $Li_{1-z}Ni_{1+z}O_2$ layered oxides and the evidence of the presence of copper pairs in the NASICON-type phosphate $CuZr_2 (PO_4)_3$. Are also reported some significant examples for which XAS spectroscopy is decisive with other characterization methods as (i) Raman spectroscopy for glasses (ii) Mossbauer spectroscopy for $LiNi_{1+z-t}Fe_To_2$ oxides (iii) magnetic measurements for Ce-based intermetallic compounds.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.143-149
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• 1993

Ginseng root explants and calli induced from selected cell lines were cultured on modified Murashige and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical composition and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of calli, the concentrations of 2, 4-D and sucrose were the range of 1 to 3 mg/${\ell}$l and 1 to $3\%,$ respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magmesian plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng. The patterns of ginsenosides, pharmacologically useful component, were different among the cell lines and contents of ginsenosides were much higher in selected cell lines than in original cell line.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.274-280
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• 2001

The chemical forms of calcium compounds in perilla leaves and their changes after harvest were investigated. The four types of calcium compounds extracted were as follows: water soluble calcium(F-I: mainly water soluble organic acid salts and calcium ion), IN-sodium chloride soluble calcium(F-II: calcium-pectate and calcium-carbonate), 2%-acetic acid soluble calcium(F-III: calcium-phosphate), and 5%-hydrochloric acid soluble calcium(F-IV: calcium-oxalate). The calcium content of perilla leaves was not found to vary with their age. Relatively high levels of F-l (28.4~39.5) and F-II (34.4~47.4) were found in young and mature leaves while the F-IV constituted 15.6~21.6% of the total calcium. The F-IV calcium contents of perilla. spinach and jaso were 16.8, 42.4 and 22.3%, respectively. In contrast to calcium. magnesium existed as water soluble magnesium at the highest content of 90.6% in spinach while 62.9% and 16.8% of the total magnesium existed as water soluble magnesium in perilla and jaso, repectively. The change in vitamin C and F-IV calcium content were examined for 7 days after harvest. Vitamin C content decreased slowly at the beginning but rapidly from the 4th day after harvest. On the other hand, the F-IV calcium content increased slowly at the beginning and rapidly from the 4th day of observation. This result suggests that the increase in F-IV calcium is related to the decrease in vitamin C content. This phenomena was more distinctly observed at 2$0^{\circ}C$ than 5$^{\circ}C$.