• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.197-208
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• 2014

A novel protease gene from Bacillus gibsonii, aprBG, was cloned, expressed in B. subtilis, and characterized. High-level expression of aprBG was achieved in the recombinant strain when a junction was present between the promoter and the target gene. The purified recombinant enzyme exhibited similar N-terminal sequences and catalytic properties to the native enzyme, including high affinity and hydrolytic efficiency toward various substrates and a superior performance when exposed to various metal ions, surfactants, oxidants, and commercial detergents. AprBG was remarkably stable in 50% organic solvents and retained 100% activity and stability in 0-4 M NaCl, which is better than the characteristics of previously reported proteases. AprBG was most closely related to the high-alkaline proteases of the subtilisin family with a 57-68% identity. The secretion and maturation mechanism of AprBG was dependent on the enzyme activity, as analyzed by site-directed mutagenesis. Thus, when taken together, the results revealed that the halo-solvent-tolerant protease AprBG displays significant activity and stability under various extreme conditions, indicating its potential for use in many biotechnology applications.

• Journal of Physiology & Pathology in Korean Medicine
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• 제31권3호
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• pp.188-193
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• 2017

This study investigated the antioxidant activities of distilled water, ethanol and methanol extracts of Plunus mume flower buds (PFB). The various solvent extracts of PFB were evaluated for their total polyphenol, flavonoid, reducing power and free radical scavenging activities by FRAP and DPPH analysis. The ethanol extract of PFB contained significantly higher amounts of total polyphenols (145 mg GAE/g) and flavonoids (25.43 mg QE/g) than methanol (132 and 25.42) and distilled water (113.6 and 18.04). Among solvent extracts of PFB, the ethanol extract showed the highest antioxidant activities. The 100% ethanol extract of PFB contained significantly higher amounts of total polyphenols and flavonoids than 70% and 50% ethanol extracts. Moreover, the 100% ethanol extract of PFB showed high efficacy in DPPH radical scavenging activity and in collagenase inhibition activity. This results suggest that 100% ethanol extract of PFB has the most effective antioxidant capacity compared to the methanol and water extracts tested in the present study. Thus, it can be applied for the effective extraction of functional material from PFB for usage of cosmeceutical and/or food industries.

• Applied Chemistry for Engineering
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• 제17권6호
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• pp.580-585
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• 2006

UV-thermal dually curable coating materials were prepared by the sol-gel method. Nano-sized colloidal boehmite was treated with various organo silane coupling agents. These materials could be well dispersed in various alcohols and relatively polar organic solvents such as tetrahydrofuran and acetonitrile. The coating films were prepared by a spin coating method on various substrates, which were characterized by FT-IR, Si/Al CP MAS NMR spectra, UV-Vis spectrophotometer, FE-SEM, Taber abraser, haze meter, and pencil hardness tester. The effects of molar ratio and types of silane coupling agents, curing method and ion-shower treatment were investigated. Dually curable coating method offered an optimally good quality film in both hardness and transmittance. The transparency and the hardness of the prepared films were increased with amounts of 3-(trimethoxysilyl)propylmethacrylate, and (3-glycidyloxypropyl)trimethoxysilane, respectively. The adhesion between coated layer and substrate could be enhanced by ion-shower treatment.

• Journal of Integrative Natural Science
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• 제14권3호
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• pp.99-106
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• 2021

A mixture of alcohol and water is commonly used as antifreeze, liquor, and the fundamental solvents for the manufacture of cosmetics, pharmaceuticals, and inks in our daily life. Since various properties of alcohol water mixtures such as density, boiling or melting point, viscosity, and dielectric constant are determined by their mixing ratio, it is very important to know the mixing ratio to predict their properties. One of simple method to find the mixing ratio is measuring the density of the mixtures. However, it is not easy to predict the mixing ratio from the density of the mixtures because the relationship between mixing ratio and density has not been established well. The relationship is dependent on the relative sizes of solute and solvent molecules, and their interactions. Recently, an empirical model to predict the density of glycerol water mixture from their mixing ratio has been introduced. The suggested model is simple but quite accurate for glycerol water mixture. In this article, we investigated the applicability of this model to different alcohol water mixtures. Densities for six different alcohol water mixtures containing various alcohols (e.g., ethylene glycol, 1,3-propane diol, propylene glycol, methanol, ethanol, and 1-propanol) were simulated and compared to experimentally measured ones to investigate the applicability of the model proposed for glycerol water mixtures to other alcohol water mixtures. The model predicted the actual density of all alcohol water mixtures tested in this article with high accuracy at various ratios. This model can probably be used to predict the mixing ratio of other alcohol water mixtures from their densities beyond 6 alcohols tested in this article from their densities.

• Journal of Microbiology and Biotechnology
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• 제34권2호
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• pp.436-456
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• 2024

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80℃. In addition, the enzyme showed a half-life of 15 h at 80℃, and there was a 60% increase in its activity at 10 mM Ca²⁺ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

• Journal of the Korean Society of Food Culture
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• 제16권3호
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• pp.243-249
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• 2001

Antibacterial activities in each part of watercress(Oenanthe javanica D.C.) grown under different culture conditions were measured to determine the possibility to use watercress as a resource to develop the antibacterial substance. The leaves of watercress were extracted with methanol and the methanol extract was further fractionated with various organic solvents. Antibacterial activities against Shigella dysenteriae ATCC 9361 in all fractions were determined according to the agar diffusion method using paper disc. Methanol extract of watercress leaves was more effectively inhibited the growth of the tested bacteria than the extracts of roots or stems at the concentration of 0.5 g eq./disc, and the extract of watercress from Hwasoon was the most effective one as compared to others. Phenolic and neutral fractions fractionated from methanol extract of watercress had a considerable inhibiting activity on the growth of the bacteria, but acidic and basic fractions did not show any inhibitory effect. Minimum inhibitory concentrations of phenolic and neutral fractions against Shigella dysenteriae ATCC 9361 were $400\;{\mu}g/disc$ and $550\;{\mu}g/disc$, respectively.

• Proceedings of the Ginseng society Conference
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• 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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• pp.102-110
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• 1990

Antitumor polyacetylenlc alcohol, panaxytriol (Ci7 H2603), was isolated and purified from a Powder of the root of Panax ginseng C.A. Meyer. Panaxytriol Possesses unusual Property of being soluble in both water and organic solvents. Panaxytriol inhibited the growth of various kinds of human cultured cell lines in dose-dependent fashion in vitro. The in vivo effects of panaxytriol were tested against C57BU6 mice transplanted with Bl6 melanomas. Panaxytriol (8 and 40 mg/kg) administered intramuscularly (im) produced significant tumor growth delays in mice. Although a detailed mechanism of growth inhibition by panaxytriol is unknown, preliminary results appear to implicate a surface membrane site of action. And its action seems to be more dose-dependent than time-dependent. Finally, panaxytriol pharmacokinetics was evaluated in mice given single 8 mgrkg doses intraperitoneally(ip) or im. Serum panaxytriol content was measured using both tumor growth inhibitory assay and a gas chromatographic method. The maximum serum panaxytriol content after ip and im administration was 35.0 and 1.61 ug/ml respectively. These results indicate that the compound may act as cytotoxic substance even in-patients. Keywords Panax ginseng, panaxytriol, tumor growth inhibition

• Macromolecular Research
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• 제9권4호
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• pp.220-227
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• 2001

The polymerization of 1,6-heptadiyne was carried out by molybdenum and tungsten-based transition metal catalysts. This polymerization by MoCl$\_$5/ alone proceeded well to give a quantitative yield of polymer. The effect of monomer to catalyst mole ratio (M/C), initial monomer concentration ([M]$\_$0/), and the polymerization temperature for the cyclopolymerization of 1,6-heptadiyne was studied and discussed. The polymerization solution exhibited red color even after 30 min of polymerization time. The resulting polymers were mostly brown powders and mostly insoluble in any organic solvents although the polymerization proceeded in homogeneous manner in some cases. The polymer structure was characterized by various instrumental methods to have the conjugated polymer backbone structure carrying cyclic recurring unit. The thermal and morphological properties of the resulting poly(1,6-heptadiyne) were also discussed.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.577-584
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• 2001

An antimicrobially active bacterium which was identified as Bacillus brevis, was isolated from kimchi. The antimicrobial activity was found against various Gram-positive and Gram-negative bacteria including some pathogens food-spoilage microorganisms, and some yeast strains. The antimicrobial activity was especially strong against Bacillus anthracis and Shigella dysenteriae. The strong activity was observed during an early stationary phase in the culture when incubated at $37^{\circ}C$ with initial medium pH of 6.8. The antimicrobial activity was found to be stable at $90^{\circ}C$ for 30 min and in the pH range of 3-11, and it was insensitive to organic solvents including acetone, acetonitrile, ethanol, and methanol. Analysis of the bacterocin on tricine-sodium dodecyl sulfate-polyacrylamide gel suggested a molecular mass of approximately 4.5-6.0 kDa. The antimicrobial substance was characterized as a bacteriocin, because of its proteinaceous nature and low molecular weight. The bacteriocin could potentially be used as a food preservative, because of its thermostable property and broad antimicrobial spectrum.

• Journal of Microbiology and Biotechnology
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• 제8권5호
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• pp.449-454
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• 1998

A thennostable chitosanase was purified from Bacillus sp. KFB-C108, by fractionation of 30 to 70% saturation with ammonium sulfate, DEAE-Toyopearl chromatography, Butyl-Toyopearl chromatography, and TSK-Gel HW-55F gel filtration. The purified enzyme showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis, and the molecular weight was estimated to be 48 kDa. The enzyme degraded soluble chitosan and colloidal chitosan, but did not degrade glycol chitosan, chitin, and the other compounds investigated. There was no effect on the chitosanase activity by treatment with chelating agents, alkylating agents, and various metals investigated, and only cobalt ions inhibited the activity. Optimum temperature and pH were $55^{\circ}C$ and 6.5, respectively. The enzyme was stable after heat treatment at $80^{\circ}C$ for 10 min or $70^{\circ}C$ for 30 min and fairly stable in several organic solvents as well. Chitosan was hydrolyzed to $(GlcN)_4$as a major product by incubation with the enzyme.