• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1521_1522
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• 2009

Chemotaxis is the directed movement of cells in gradients of signaling molecules, an essential biological process that underlies morhpogenesis during development, and the recruitment of immune cells to sites of infection. Especially, bacterial chemotaxis has utilized as an important prelude to study metabolism, prey-predator relationship, symbiosis, other ecological interactions in microbial communities. Recently, novel analytical formats integrated with microfluidics were introduced to investigate the chemotaxis of the cells with the precise control of chemical gradient and small volume of cells. In this study, we present a method to detect bacterial chemotaxis by direct fluidic contacting. The developed fluidic-handling method is driven by capillary force, hydrophobic barrier and a cohesion force between fluids. We have investigated the chemotactic response of E Coli. and Pseudomonas aeruginosa to three kinds of chemoeffectors such as HEPES buffer, peptone and chloroform.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.246-250
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• 1991

Conditions for the production and regeneration in Lactobacillus bulgaricus protoplasts were investigated. Protoplasts of L bulgaricus strains were obtained by treatment with mutanolysin and lysozyme together in a protoplast forming buffer containing 0.02 M N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) (pH 7.0) and 0.5 M sucrose. High protoplast yield was obtained from cells cultured in the de Man, Rogosa and Sharpe(MRS) medium at the middle to late logarithmic growth phase. Regeneration was efficiently accomplished with a complex medium containing 1% sucrose, 20 mM $MgCl_2$, 5% gelatin, and 0.5% bovine serum albumin. The frequency of regeneration of protoplasts was 10~20% after 5 days of incubation at $30^{\circ}C$.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.193.2-194
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• 2003

Effect of phenylpropanoids on Phospholipase A2 (PLA2) and phosphodiesterase (PDE) activities in the asthmatic lung tissue were studied in guinea pigs. Bronchial asthma were introduced by the challenge of aerosolized ovalbumin (OA) in the double-chambered plethysmograph at twenty one days after sensitization of OA in guinea pigs. Bronchoalveolar lavage fluids (BALF) were taken by brochalveolar lavage with HEPES buffer. (omitted)

• The Korean Journal of Food And Nutrition
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• v.5 no.2
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• pp.77-83
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• 1992

The optimum conditions and mechanisms for the plasmid-mediated genetic transformation of intact cells of Bacillus brevis Pl76-2, an extracellular protein producing bacterium by electroporation were investigated. It was found that pUB110 Plasmid DNA can be introduced into intact bacterial cells by electroporation. The frequency of transformation by this electroporation system depended upon the initial electric field strength, the capacity of the electric discharge capacitor, growth stage, number of successive pulses and composition of electroporation buffer. It was effective for transformation that cells were harvested, washed and resuspended with HSM [7M HEPES(PH 7.4), 272mM sucrose, 1 mM MgCl2] electroporation buffer when cell growth was attained to 1.2 at OD660. A maximum frequency of transformation of 2.40$\times$104 transformants per$\mu$g plasmid DNA was obtained by two succesive Pulses with an initial electric field strength of 12.5kV/cm and with a capacitance of 7.3uF.

• Microbiology and Biotechnology Letters
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• v.21 no.2
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• pp.101-106
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• 1993

The optimal conditions for the production and regeneration of L. helveticus protoplasts were examined. The protoplast formation of L. helveticus was most efficient obtained when the cells grown to mid and late logarithmic phase in MRS medium were used. The maximum number of protoplasts was obtained when lysozyme and mutanolysin were used to lysis the cell wall in 20mM HEPES buffer (pH 7.0) containing 1M sucrose. Regeneration was accomplished with a complex medium containing 10% sucrose, 10mM MaCl2, 20mM CaCl2, 5% gelatin and 0.5% bovine serum albumin. The regeneration frequency of the protoplasts was 10-20% after 5 days of incubation at 30C.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1061-1064
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• 2013

A known $Hg^{2+}$ selective rhodamine B derivatised probe 1 was reinvestigated as a colorimetric and fluorescent probe for $Cu^{2+}$ through changing the applied solvent media. Probe 1 exhibited good selectivity and sensitivity to $Cu^{2+}$ in $CH_3CN-H_2O$ (7:3, v/v, HEPES 10 mM, pH 7.0) solution with a detection limit of $9.74{\times}10^{-7}$ M. The $Cu^{2+}$ sensing event was proved to be irreversible through hydrolysis of 1 to release rhodamine B.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3696-3700
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• 2012

The colorimetric and fluorescent cyanide recognition properties of 2-[(9-ethyl-9H-carbazol-3-yl)methylene]-propanedinitrile (1) in $CH_3CN-H_2O$ (2/1, v/v, HEPES 10 mM, pH = 7.0) solution were evaluated. The optical recognition process of probe 1 exhibited high sensitivity and selectivity to cyanide ion with the detection limit of $2.04{\times}10^{-6}$ M and barely interfered by other coexisting anions. The sensing mechanism of probe 1 is speculated to undergo a nucleophilic addition of cyanide to dicyanovinyl group present in compound 1. The colorimetric and fluorescent dual-modal response to cyanide makes probe 1 has a potential utility in cyanide detection.

• Journal of Ginseng Research
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• v.27 no.2
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• pp.52-55
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• 2003

The present experiment was perf'3rmed to investigate the protective effects of ginseng total saponin (GTS) and possible mechanisms on the hepatocytotoxicity induced by tert-butylhydroperoxide (t-BuOOH), 4-Bromo-calciumu ionophore A23187 (Br-A23187) and KCN. Hepatocytes were isolated by collagenase perfusion of livers from fasted male Sprague Dawley rats and cultured overnight. After various treatments in Krebs-Ringer-HEPES buffer at pH 7.4, cell viability was determined by propidium iodide using fluorocytometry. GTS (5-20 ${\mu}$M) inhibited cell killing induced by t-BuOOH, and KCN, dose-dependently. However, GTS did not inhibit Br-A23187-induced cell killing. These findings support that GTS could protect the hepatocytoxicity induced by some toxic chemicals. The mechanisms of these protective effects by GTS seem to be associated with antioxidant activity and increase of cellular ATP.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.195.2-196
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• 2003

Cinnamic acid derivatives (CAD) originating from medicinal plants have some biological activity. In this study. effect of CAD on heterologous passive cutaneous anaphylaxis (PCA) were studied by the method of Levine and Vaz(1970). Anti-serum was prepared from OA-sensitized male Balb/c mouse at two weeks after the last challenge of ovalbumin (OA) and alumina gel, and these serum diluted with HEPES buffer by means of the heterologous PCA titer, i.e. the highest dilution inducing PCA in rats. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.127.1-127.1
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• 2003

Effect of Compound-A, a phenylpropanoid isolated from Arctium lappa fruit, on the early- (EAR) and late-phase asthmatic responses (LAR) of guinea pigs were studied in vivo. Guinea pigs were sensitized by injection of 100 mg of ovalbumin (OA). Twenty-one days after sensitization, animals were challenged with exposure to aerosolized 1 % OA for five minutes in double-chambered plethysmograph box with jet nubulizer. Immediately and twenty-four hours after challenge, EAR and LAR ashmatic responses were determined the tidal volume (TV), respiration rate (RR) and specific airway resistance (sRaw), and then animals anethetized and taken the bronchoalveolar lavage fluid (BALF) by lavage the lung with HEPES buffer through cannulation into trachea. (omitted)