• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.212-219
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• 2020

The physicochemical characterstics of El Salvadoran Coffea arabica cv. Bourbon coffee extracts under various roasting conditions were investigated. Green beans were roasted under four different conditions (Light-medium, Medium, Moderately dark, and Very dark). The coffee extracts were prepared by using the espresso or drip methods. As the roasting degree increased, the coffee bean moisture content decreased and the ash content increased. The lightness and yellowness of the beans and coffee extracts decreased along with the increasing roasting degree. In the drip coffee, the reducing sugar content decreased and the pH value increased along with the increasing roasting degree. Both in the espresso and drip coffee, total organic acid and chlorogenic acid contents decreased, while the caffeine content increased along with the increasing roasting degree. Therefore, it is suggested that the roasting degree affects the physicochemical characteristics of coffee extracts.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.225-235
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• 1986

Effects of anions on p-Aminohippurate (PAH) transport across the basolateral membrane (BLM) were studied. Basolateral membrane vesicles were isolated from rabbit renal cortex by using a self-orienting Percoll-gradient centrifugation and $Mg^{2+}-precipitation$. The characteristics of the membrane vesicles was examined by marker enzyme activity, membrane orientation and transport studies. The Na-K-ATPase activity in the fraction containing BLM vesicles was enriched 9·fold, and the alkaline phosphatase activity in the fraction containing BBM vesicles was increased 9-fold, compared with those of the homogenate. The transport properties of the two membrane preparations were studied by a rapid filtration technique. The uptake of PAH by BLM was sensitive to changes in medium osmolarity and inhibited by probenecid. When the uptake of $50{\mu}M$ PAH in voltage-clamped BLM vesicles was determined in the presence of various anions in the incubation medium, cis inhibitions by $SO_4\;and\;SSO_3$ were observed in the presence of sodium gradient (out>in). Sodium-dependent PAH uptake was inhibited competitively by external $SO_4$ PAH uptake in BLM vesicles loaded with 20 mM acetate and $SO_4\;or\;200\;{\mu}M$ PAH was significantly stimulated as compared with unloaded vesicles. The extent of trans-stmulation of PAH uptake by $SO_4$. was increased with the inside concentration of $SO_4$. This trans-stimulatory effect by $SO_4$, was observed to be additive in the presence of Na gradient and completely inhibited by 2 mM probenecid and 1 mM SITS. These results demonstrate that PAH/anion exchange is present in BLM of renal cortex and in this exchange mechanism inorganic as well as organic anions are involved as substrates.

• Microbiology and Biotechnology Letters
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• v.3 no.2
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• pp.63-68
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• 1975

A biological active substance was isolated from the cultured medium of Streptomyces sp. and its biochemical characteristics were investigated. Isolation process of the substance was as follows; the pH of filterate of the cultured medium was adjusted to 3.0 with N-hydrochloric acid and saturated with sodium chloride, then chloroform was added to this filterate in one fifth portions and stirred vigorously. After extracting the active substance with chloroform in 3 stages, the chloroform layer combined and evaporatea after dehydrating with sodium sulfate. The substance was found to be to be toxic to various fresh water fishes; the lethal dose for an average size Pseudorasbora parva T. et. S. was 50ug per ml. In the acidic condition, the toxicity of the substance remained fora long time, while in the alkaline state, the toxicity was decreased very fast. This substance was found to be stable to organic solvents, but labile to heat treatment. The maximal revival time of Pseudorasbora parva T. et. S. was about 20 minutes in 25 ug/ml of the substance solution.

• Elastomers and Composites
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• v.45 no.3
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• pp.199-205
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• 2010

Medium-density fiberboard (MDF) is widely used as an indoor building materials. However, formaldehyde resins, commonly used to bind MDF together, emit formaldehyde and other volatile organic compounds that cause health risk at sufficient concentration. In this study, condensed tannin having formaldehyde absorption ability was used to solve the problem of formaldehyde emission generated from surface material. The synthesis of melamine-formaldehyde resin and reaction of melamine-formaldehyde and condensed tannin were analyzed by FT-IR spectrum. Also surface properties, such as shear force, impact strength, tape adhesion, pencil hardness and gloss retention were measured. Free formaldehyde analysis was performed to analyze remaining unreacted formaldehyde. According to the results, the optimum shear force and impact strength could be obtained by 10 wt.% usage of condensed tannin. In cases of pencil hardness and gloss retention, the optimum properties could be obtained at 20 wt.% of condensed tannin. The amounts of formaldehyde emission of surface material containing 20 wt.% of condensed tannin was 59 ${\mu}g/m^2{\cdot}h$. The amounts of formaldehyde emission could be reduced 3 times by using 20 wt.% of condensed tannin.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.29-36
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• 1996

This experiment was conducted to investigate the effects of the application of complete fertilizer on the yields and quality of leaf tobaccod grown in soils with different fertility levels. The contents of inorganic nitrogen, organic matter and available phosphorus in the soil with high fertility level were shown to be more than those in the soils with medium and low fertility levels of the experimental fields. The contents of total nitrogen, nicotine and reducing sugar in the tobacco leaf were more than those in the cutters tobacco. The contents of total nitrogen and nicotine in the leaf tobacco increased as the application amounts of the fertilizer(10:10:20) increased, however, the reducing sugar contents in the leaf tobacco decreased. The increase in the yields of leaf tobacco was detected at the application amount of 75kg/10a in soils with high fertility level, but for high yield of leaf tobacco in the soils with low and medium levels the application amount of the fertilizer was found to be over 100kg per 10a. The quality (price/kg or price/kg ${\times}$ yield) of the leaf tobacco was known to be excellent at 50~75kg/10a of the application amount of the fertilizer(10:10:20) in soil with high fertility level and over 100kg/10a in the other soils in the experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.1
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• pp.29-36
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• 2009

Fourteen bacterial strains were isolated from crop rhizosphere and identified as phosphate solubilizing bacteria (PSB) by 16S rRNA analysis. Only 3 strains exhibited a strong ability to solubilize insoluble phosphate in agar medium containing a hydroxyapatite. The rates of P solubilization by isolates were ranged from 200 and $2300\;mg\;L^{-1}$, which are inversely correlated with pH in culture medium. Furthermore, HPLC analyses reveal the production of organic acid from the culture filtrates of PSB. Among these, strain Acinetobacter sp. released only gluconic acid, Pseudomonas orientalis produced gluconic acid which was subsequently converted into 2-ketogluconic acid, and Enterobacter asburiae released acetic acid and succinic acid. On the other hand, P. orientalis and E. asburiae released $372\;mg\;L^{-1}$ and $191\;mg\;L^{-1}$ of IAA into broth culture, respectively, while Acinetobacter sp. did not produce IAA. Furthermore, in vivo study showed that plant growth promoting effect by bacteria generally seemed to be increased IAA production and phosphate solubilization.

• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.126-137
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• 2023

In this study, we isolated lactic acid bacteria from Allium wakegi and examined the usability of culture supernatants obtained from these lactic acid bacteria. The antibacterial activity of the culture supernatant obtained from the isolated lactic acid bacteria against the pathogens Escherichia and Salmonella spp. was measured. The obtained lactic acid bacteria culture medium showed significant antibacterial activity against pathogenic bacteria in a dose-dependent manner. The effects of pH and heat denaturation on the observed anti-pathogenic bacterial activity was also investigated. Adjusting the culture supernatant to pH 7 resulted in loss of all antibacterial activity against pathogenic bacteria, suggesting that the antibacterial activity of the obtained culture supernatant against pathogenic bacteria is influenced by organic acids. Assessment of the heat stability of the anti-pathogenic bacterial activity revealed that heat treatment did not diminish activity. The obtained lactic acid bacteria culture medium is thus stable against heat.

• Research in Plant Disease
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• v.30 no.2
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• pp.148-156
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• 2024

Ralstonia pseudosolanacearum, a plant pathogenic bacterium that can survive for a long time in soil and water, causes lethal wilt in the Solanaceae family. Sigma S is a part of the RNA polymerase complex, which regulates gene expression during bacterial stress response or stationary phase. In this study, we investigated the role of sigma S in R. pseudosolanacearum under stress conditions using a rpoS-defective mutant strain of R. pseudosolanacearum and its wild-type strain. The phenotypes of rpoS-defective mutant were complemented by introducing the original rpoS gene. There were no differences observed in bacterial growth rate and exopolysaccharide production between the wild-type strain and the rpoS mutant. However, the wild-type strain responded more sensitively to nutrient deficiency compared to the mutant strain. Under the nutrient deficiency, the rpoS mutant maintained a high bacterial viability for a longer period, while the viability of the wild-type strain declined rapidly. Furthermore, a significant difference in pH was observed between the culture supernatant of the wild-type strain and the mutant strain. The pH of the culture supernatant for the wild-type strain decreased rapidly during bacterial growth, leading to medium acidification. The rapid decline in the wild-type strain's viability may be associated with medium acidification and bacterial sensitivity to acidity during transition to the stationary phase. Interestingly, the rpoS mutant strain cannot utilize acetic acid, D-alanine, D-trehalose, and L-histidine. These results suggest that sigma S of R. pseudosolanacearum regulates the production or utilization of organic acids and controls cell death during stationary phase under nutrient deficiency.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.725-736
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• 2013

In order to acquire morphological characteristics and genetic characteristics of pathogen that causes anthrax to chestnut, anthrax was separate and identified in Gongju, chungnam chestnut plantation. Antagonistic microorganisms and plant extracts were selected for control of anthrax. Medium maturing variety treatment of 250 dilution fold in field was control at 71.2% and treatment of 500 dilution fold was control at 64.4% and treatment of 1000 dilution fold was control at 40.7%. Storage control value of Jabong in $25^{\circ}C$ after treatment in field is 61.7% at 250 dilution fold, 62.8% at 500 dilution fold, 40.9% at 1000 dilution fold treatment.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.795-801
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• 2012

Nanoparticles have received significant attention because of their unusual characteristics including high surface area to volume ratios. Thiol ligand have been used as stabilizers of metal nanoparticles since Brust et al. They reported the preparation method of ligand capped metal nanoparticles by protecting the nanoparticles with a self-assembled monolayer of dodecanethiolate. In this method, volatile organic compounds (VOCs) were used as sovents. This study was carried out to replace these VOCs with room temperature ionic liquids (RTILs). We used two type of ILs to prepare metal nanoparticles. One is a hydrophobic IL, [BMIM][[$PF_6$] (1-Butyl-3-methylimidazolium hexafluorophosphate) purchased from IL maker, C-Tri from Korea and the other one is a hydrophilic one, [BMIM][Cl] (1-Buthy-3-methylimdazolium chloride) sinthesized by us. In the case of preparing Ag and Au nanoparticles using [BMIM][Cl], we didn't use phase transition reagents and ethanol because it has hydrophilic property and preparing Au, Ag nanoparticles using [BMIM][[$PF_6$] the method is as same as Brust et al.'s except using [BMIM][[$PF_6$] instead of organic solvent because it has hydrophobic property. FT-IR and UV-vis, TEM, TGA analysis have been used in an attempt to determine the particle size and verify functional groups. The particle size obtained from TEM was very similar to those obtained by Brust et al. This is a clear example of ligand capped metal nanoparticles prepared using ionic liquids. And the experimental result demonstrated ionic liquids can act as a highly effective medium for the preparation and stabilization of gold and silver metal nanoparticles.