• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.185-185
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• 1994

관상동맥은 전기적으로 자극하여도 활동전위가 쉽게 유발되지 않는 조직인데, 이는 세포내의 $Ca^{2+}$에 의해서 활성화되는 $K^{+}$통로때문이라고 여겨지고 있다. 저자들은 단일 이온통로 수준에서 이러한 관상동맥 $K^{+}$ 통로의 성질을 조사하고, 아울러 $K^{+}$ 통로 개방제를 포함한 몇가지 약물이 $K^{+}$ 통로에 미치는 영향을 알아보고자 본 연구를 수행하였다. 막소포는 돼지의 심장에서 관상동맥을 분리하여 균질화 및 원심분리하여 준비하였으며, sucrose 20/30%에 있는 층을 취하여 분주한 후 -7$0^{\circ}C$로 보관하여 사용하였다. 평지방막은 1-palmitoyl, 2-oleoyl-phosphatidyl ethanolamine과 1-palmitoyl, 2-oleoyl phosphatidylcholine (4:1)을 n-decane에 녹인지방액(25mg/m1)을 200 $\mu\textrm{m}$의 구멍에 칠하여 만들었다. 단일 $K^{+}$ 통로는 막소포 (1-5$\mu\textrm{g}$/ml)를 평지방막의한쪽에 추가하고 자석으로 저어 융합이 되도록 하였으며, 통로의 활성은 막의 양쪽에 150 mM KCI, 10 mM HEPES-KOH, 0.5 mM EGTA, 0.6 mM $CaCl_2$ (pH 7.2)로 된용액이 존재하는 상태에서 막전압을 다르게 하며 기록하였다. 단일 이온 통로 전류는 amplifier를 통하여 VCR tape에 녹화하여 후에 분석에 이용하였으며, 동시에 종이기록지에 기록하였다. 단일이온통로 활성의 분석은 pClamp (Ver5.5)를 이용하여 수행하였다. 관상동맥에서 가장 흔히 기록되는 이온통로는 막전압과 $Ca^{2+}$의 농도에 의하여 변하는 $K^{+}$ 통로이었는데 pCa 4.0과 -10 mV에서 초기 활성도(Po)는 0.1에서 0.8까지 다양하였다. 전류와 전압과의 관계는 -60 - +60mV의 전압범위에서 직선형이었다.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.739-744
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• 1991

A palatable paste-type lactic fermented rice (LFR) was prepared by lactic acid fermentation after liquefaction and saccharification of cooked rice. A mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus (1 : 1) produced the LFR of the best quality. A great improvement in quality of the LFR was achieved by 0.02% each ${\alpha}-amylase$ and glucoamylase treatment during the fermentation (simultaneous saccharification and fermentation), which resulted from the increased sourness and sweetness and the decreased size of solid particles contained in the LFR. The resulted LFR was superior in quality. Physical and chemical properties of the LFR were evaluated.

• Polymer(Korea)
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• v.38 no.4
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• pp.502-509
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• 2014

Carbon-based nanoplatelets such as graphene oxide (GO) sheets and graphite nanoplatelets (GNPs) are frequently used as conductive nanofillers for polymer nanocomposites. In this study, polystyrene (PS)/GO and PS/GNP nanocomposites were prepared through a latex technology and investigated to compare the effect of nanofillers on rheological and electrical properties of the PS nanocomposites. PS particles were prepared by emulsifier-free emulsion polymerization and GO was synthesized by using the modified Hummers' method from graphite. Hydrophilic GO was dispersed in aqueous PS suspension, but hydrophobic GNPs were dispersed with the help of a surfactant. In comparison with PS/GO nanocomposites, the rheological properties of PS/GNP counterparts were not too high because GNP existed in aggregates of graphene layers. Conducting pathways of PS/GO and PS/GNP nanocomposites were achieved at the electrical percolation threshold of 0.50 and 5.82 wt%, respectively. The reason for enhanced electrical conductivity in PS/GO nanocomposites is that GO was thermally reduced during molding.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.202-210
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• 1994

To investigate the feasibility of mucosal delivery of $[D-Ala^6]$ LHRH, a potent analogue of LHRH, enzymatic proteolysis of $[D-Ala^6]$ LHRH and inhibitory effect of medium chain fatty acid salts(MFA) were studied using rabbit mucosal homogenate. $[D-Ala^6]$ LHRH incubated in homogenates of rectal(RE), nasal(NA) and vaginal(VA) mucosa were assayed by HPLC. The degradation of $[D-Ala^6]$ LHRH followed the first order kinetics. The degradation products were found as $[D-Ala^6]$ $LHRH^{1-7}$(m-i), to a lesser extent, $[D-Ala^6]$ $LHRH^{1-9}$(m-ii) and $[D-Ala^6]$ $LHRH^{1-3}$(m-iii) by the method of amino acid analysis(PITC method). The formation of$[D-Ala^6]$ $LHRH^{1-7}$ was not inhibited by the addition of disodium ethylenediaminetetraacetic acid but inhibited by sodium tauro-24,25-dihydrofusidate, suggesting that endopeptidase 24.11(EP 24.11) cleaves the $Leu^7-Arg^8$ bond of $[D-Ala^6]$ LHRH and is the primary $[D-Ala^6]$ LHRH degrading enzyme. The patterns of $[D-Ala^6]$ LHRH degradation indicated that EP 24.11 exists in each mucosal homogenate with the order of RE>NA>VA. MFA significantly inhibited the proteolysis of $[D-Ala^6]$ LHRH. The addition of sodium caprate(1.0%) or sodium laurate(0.5%) to the each mucosal homogenate completely protected $[D-Ala^6]$ LHRH from the degradation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.1
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• pp.20-29
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• 1992

In $BaTiO_3-NaNbO_3$ system, complete series of solid solution occurs and $30BaTiO_3{cdot}70NaNbO_3$ composition is congruently melted. Single crystals of $30BaTiO_3{cdot}70NaNbO_3$, composition were grown by Czochralski method in this investigation. Single crystals with dimensions of 15 - 20mm diameter and 20 - 30mm length, were grown at the pulling rate of 2.0mm/h and the rotation rate of 5.0 -l0rpm. Core structures were found in the grown crystals and inclusions, cellular boundaries existed at the core region. The origin of core occuring was unstability of the crystal- melt interface due to the poor conductivity of latent heat through the crystal during the crystal growing process. Obtained crystals were optically homogeneous except the core region and showed high optical transmittance in the visible range.

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.370-376
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• 2011

This study was performed to investigate the antioxidative effect of Ligusticum chuanxiong Hort extracts (LCE) against the hyperlipidemia of high-fat diet-fed obese rats. The rats were divided into the three groups (normal group, control group and sample group) to perform the experimental research. 1.5 ml/kg of LCE was intraperitoneally administered into the sample group for 21 days. The equal dose of 0.9% saline was intraperitoneally administered into the normal group and the control group. On day 22, they were anesthetized with ether and dissected. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) were examined in serum of rats. Superoxide dismutase (SOD) was measured in mitochondrial fraction. Malondialdehyde (MDA), catalase (CAT), and glutamate peroxidase (GPx) were determined in liver homogenate. High-fat diet markedly increased the levels of AST, ALT and MDA, significantly decreasing those of SOD, CAT and GPx. But Ligusticum chuanxiong Hort-pretreatment decreased the levels of AST, ALT, and MDA. increasing those of SOD, CAT and GPx. These results demonstrated the antioxidative effects, suggesting that LCE could be the candidate for the functional material.

• Journal of Food Hygiene and Safety
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• v.3 no.2
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• pp.53-58
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• 1988

This study was carried out to discuss a colorimetric method for the determination of nitrite in meat products issued by the Ministry of Health and Social Affaires of Korea (1985). 1) The recovery rates of nitrite of test solution extracted in the room temperature were higher than those obtained by the heating extraction. 2) In the room temperature, samples prepared with the sUce were more effective than the blendina method and the distlled water as extractina solvent for nitrite was more effective tban tbe phospbate buffer solution. 3) The extracting time showed that thirty minutes were enough to extract nitrite and the diazotizingcoupling reagents, 30% of sulfanilamide and N-l-naphthylethyienediamine were better than others. 4) The nitrite in a test soiution greatly decreased when the solution was distilled. In this case, the test solution should be used as a control. 5) Ten minutes were enough to couple nitrite.

• The Korean Journal of Mycology
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• v.24 no.2 s.77
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• pp.135-141
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• 1996

Auxotrophs and drug resistant mutants from the mycelia of Lentinus edodes were obtained by UV irradiation at survival rates of $0.024{\sim}2.45%$ and ethidium bromide (EtBr) enrichment after UV irradiation. The mutation rate was 0.40%, and back mutation rate was $4.81{\times}10^{-4}{\sim}8.46{\times}10^{-4}$. Various amino acid-, nucleic acid-, and vitamin-requiring auxotrophs were isolated. The concentrations of several fungicides, antibiotics and amino acid analogues inhibiting the growth of L. edodes were determined. The MIC values for cycloheximide, benomyl, and p-fluorophenylalanine were 2, 2000, and 1000 ug/ml respectively. Five p-fluorophenylalanine-resistant mutants and eight benomyl-resistant mutants were selected by UV irradiation.

• Journal of Life Science
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• v.19 no.11
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• pp.1522-1528
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• 2009

A marine bacterium was isolated from brown seaweeds for its ability to degrade alginate. Analysis of 16S ribosomal DNA sequence revealed that the strain belongs to Streptomyces like strain ALG-5 which was reported previously. New alginate lyase gene of Streptomyces sp. M3 was cloned by using PCR with the specific primers designed from homologous nucleotide sequences. The consensus sequences of N-terminal YXRSELREM and C-terminal YFKAGXYXQ were conserved in the M3 alginate lyase amino acid sequences. The homology model for the M3 alginate lyase showed a characteristic structure of $\beta$-jelly roll fold main domain like alyPG from Corynebacterium sp. ALY-1. The homogenate of the recombinant E. coli with the alginate lyase gene showed more degrading activity for polyguluronate block than polymannuronate block. The results from the multiple alignments and the homology modeling elucidated in the M3 alginate lyase can be classified into family PL-7.

• Journal of Life Science
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• v.19 no.8
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• pp.1062-1066
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• 2009

N-Acetylglucosamine kinase (GlcNAc kinase or NAGK; EC 2.7.1.59) catalyzes the phosphorylation of GlcNAc to GlcNAc-6-phosphate (GlcNAc-6-P). Despite detailed characterization of the enzyme itself, there have been few studies on the expression of NAGK in mammalian tissues. In the rat hippocampal neuron in culture, NAGK-immunoreactivity (IR) formed clusters in somatodendritic domains. In this study we characterized the NAGK clusters that protrude out the long axis of dendritic shafts. By double-labeling of the neurons with antibodies against NAGK and various synaptic proteins, we show that NAGK is positioned at the base of spines, while there were no NAGK protrusions into inhibitory postsynaptic sites. Immunoblot analysis showed that NAGK was included in synaptosomes but not in PSD fractions. Our results indicate that the NAGK clusters at the dendritic periphery protrude into spines.