• Mycobiology
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• v.38 no.4
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• pp.302-309
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• 2010

Formic acid is a representative carboxylic acid that inhibits bacterial cell growth, and thus it is generally considered to constitute an obstacle to the reuse of renewable biomass. In this study, Saccharomyces cerevisiae was used to elucidate changes in protein levels in response to formic acid. Fifty-seven differentially expressed proteins in response to formic acid toxicity in S. cerevisiae were identified by 1D-PAGE and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analyses. Among the 28 proteins increased in expression, four were involved in the MAP kinase signal transduction pathway and one in the oxidative stress-induced pathway. A dramatic increase was observed in the number of ion transporters related to maintenance of acid-base balance. Regarding the 29 proteins decreased in expression, they were found to participate in transcription during cell division. Heat shock protein 70, glutathione reductase, and cytochrome c oxidase were measured by LC-MS/MS analysis. Taken together, the inhibitory action of formic acid on S. cerevisiae cells might disrupt the acidbase balance across the cell membrane and generate oxidative stress, leading to repressed cell division and death. S. cerevisiae also induced expression of ion transporters, which may be required to maintain the acid-base balance when yeast cells are exposed to high concentrations of formic acid in growth medium.

• YAKHAK HOEJI
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• v.52 no.6
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• pp.426-433
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• 2008

The interaction of cadmium (II) ion with protocatechuic acid ($H_3PA$) and ethylenediaminetetraacetic acid (EDTA) were investigated in aqueous solution at different pH. The protocatechuic acid and EDTA/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd (II) ion with protocatechuic acid was formed in solution. Among the two potential sites of chelation present in the protocatechuic acid structure, the carboxylic function presents higher complexation power toward Cd (II). 1 : 1 Cd (II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with protocatechuic acid in 0.2 M $NH_3$ - 0.2 M ${NH_4}Cl$ (pH 8.0) buffer. These results suggest that Cd $({H_2}PA)^+$ complex has the optimal condition of chelation in buffer solution at 64.22 ${\mu}M$ protocatechuic acid (A=1.01455).

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.156-163
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• 1995

In the previous study, styrene mdleic dnhydride copolymer(SMA) as synthesized flom styrene and rnale~c dnhydr~de and further redcted with sulfuric acid to obtam water soluble SMA. In thls study, the flow dnd strcngth tests of cement mortar rmxed wth copolymers wele carried out to evaluate the capability of copolymers as high range water reducer for the con crete. It was found from flow exper~ment that the fluidity of cenient mortar rmxed wth sulfonated SMA(SSMAj was larger thdn that mxed ulth amnophenol substituted SSMA (SmSMAj. The decreasing rate of the flow of cement mortar rmxed ulth SSMA and SmSMA was significantly lower than that mixed ulth naphthalene condensate(NSC) The compressslve strength of the hardened cement mortars containing 0.5% copolymers after 28 dys curing was exarmned. 'The compressive strength of hdrdened cement mortar containing SSMA and SmSMA was mcreased up to 31% and 13%, respectively, when omp pared to the plain. As the results, the copolyniers(SSMA and SrnSMA) used in thls study are greatly expected as a good high range water reducers for the concrete.

• Journal of Environmental Health Sciences
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• v.43 no.4
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• pp.280-297
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• 2017

Objectives: We assessed pesticide exposure levels according to cultivation and crop type and investigated agricultural factors related to exposure. Methods: The participants, 341 male and 127 female farmers, were divided into three groups by cultivation crop type: chili greenhouse, cucumber greenhouse, and orchard. We collected questionnaires, socioeconomic characteristics and agricultural factors, and spot urine. Pesticide exposure was examined using four organophosphate and four pyrethroids urinary metabolites: dimethylphosphate, dimethylthiophosphate, diethylphosphate, diethylthiophosphate, Cis and Trans-3-(2-2dichlorovinyl)-2, 2-dimethylcyclopropane carboxylic acid, 3-phenoxybenzoic acid (3-PBA), Cis-3-(2-2dibrmovinyl)-2, and 2-dimethylcyclopropane carboxylic acid. Each metabolite was summed ${\Sigma}DAP$ and ${\Sigma}PY$ according to the chemical class. Results: Urinary metabolite detection rates and concentrations were similar between the greenhouse groups, but the orchard group was different. Similar 3-PBA detection rates were found in the three groups, but the geometric mean was very high in the orchard group compared to the two greenhouse groups. 3-PBA concentration in the orchard group was $4.11{\mu}g/g$ creatinine; the chili and cucumber greenhouse groups were 1.27 and $1.16{\mu}g/g$ creatinine, respectively. ${\Sigma}DAP$ was significantly associated with cultivation crop type and seasonal variation, but ${\Sigma}PY$ was not relevant. Conclusions: Our results suggest that cultivation and crop type may be correlated with different pesticide types and exposure levels. Furthermore, seasonal factors were related as potential factors influencing the level of organophosphate metabolites, but not for pyrethroid metabolites.

• BMB Reports
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• v.33 no.2
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• pp.172-178
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• 2000

The lipoxygenase was purified 35 fold to homogeneity from the Korean red potato by an ammonium sulfate precipitation and DEAE-cellulose column chromatography. The simple purification method is useful for the preparation of pure lipoxygenase. The molecular weight of the enzyme was estimated to be 38,000 by SDS-polyacrylamide gel electrophoreses and Sepharose 6B column chromatography. The purified enzyme with 2 M $(NH_4)_2SO_4$ in a potassium phosphate buffer, pH 7.0, was very stable for 5 months at $-20^{\circ}C$. Because the purified lipoxygenase is very stable, it could be useful for the screening of a lipoxygenase inhibitor. The optimal pH and temperature for lipoxygenase purified from the red potato were found to be pH 9.0. and $30^{\circ}C$, respectively. The Km and Vmax values for linoleic acid of the lipoxygenase purified from the red potato were $48\;{\mu}M$ and $0.03\;{\mu}M$ per minute per milligram of protein, respectively. The enzyme was insensitive to the metal chelating agents tested (2 mM KCN, 1 and 10mM EDTA, and 1 mM $NaN_3$), but was inhibited by several divalent cations, such as $Cu^{++}$, $Co^{++}$ and $Ni^{++}$. The essential amino acids that were involved in the catalytic mechanism of the 5-lipoxygenase from the Korean red potato were determined by chemical modification studies. The catalytic activity of lipoxygenase from the red potato was seriously reduced after treatment with a diethylpyrocarbonate (DEPC) modifying histidine residue and Woodward's reagent (WRK) modifying aspartic/glutamic acid. The inactivation reaction of DEPC (WRK) processed in the form of pseudo-first-order kinetics. The double-logarithmic plot of the observed pseudo-first-order rate constant against the modifier concentration yielded a reaction order 2, indicating that two histidine residues (carboxylic acids) were essential for the lipoxygenase activity from the red potato. The linoleic acid protected the enzyme against inactivation by DEPC(WRK), revealing that histidine and carboxylic amino acids residues were present at the substrate binding site of the enzyme molecules.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1688-1694
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• 2009

A novel strain of fluorescent pseudomonad (PB-St2) was isolated from surface-sterilized stems of sugarcane grown in Pakistan. The bacterium was identified as Pseudomonas aurantiaca on the basis of 16S rRNA gene sequence analysis and results from physiological and biochemical characteristics carried out with API50 CH and QTS 24 bacterial identification kits. Assays using substrate-specific media for enzymes revealed lipase and protease activities but cellulase, chitinase, or pectinase were not detected. The bacterium was unable to solubilize phosphate or produce indole acetic acid. However, it did produce HCN, siderophores, and homoserine lactones. In dual culture assays on agar, the bacterium showed antifungal activity against an important pathogen of sugarcane in Pakistan, namely Colletotrichum falcatum, as well as for pathogenic isolates of Fusarium oxysporium and F. lateritium but not against F. solani. The antifungal metabolites were identified using thin-layer chromatography, UV spectra, and MALDI-TOFF spectra and shown to be phenazine-1-carboxylic acid (PCA), 2-hydroxyphenazine (2-OH-PHZ), and N-hexanoyl homoserine lactone (HHL) (assessed using only TLC data). The capacity of this bacterium to produce HCN and 2-OH-PHZ, as well as to inhibit the growth of C. falcatum, has not been previously reported.

• Polymer(Korea)
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• v.34 no.1
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• pp.52-57
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• 2010

The low viscous epoxy resin(bisphenol F) with carboxylic acid as the reductants was introduced for high performance and reliability in the ACA with a low melting point alloy filler system. The curing characteristics of the epoxy resin and temperature dependant viscosity characteristic of epoxy resin at the melting temperature of LMPA were investigated by dynamic mode of differential scanning calorimetry (DSC) and rheometer, respectively. Based on these thermo-rheological characteristics of epoxy resin and LMPA, the optimum process system was designed. In order to remove the oxide layer on the surface of LMPA particle, three different types of carboxyl acid-based reductant were added to the epoxy resin. The wetting angles were about $18^{\circ}$ for carboxypropyldisilioxane, and $20.3^{\circ}$ for the carboxy-2-methylethylsiloxane, respectively.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.501-508
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• 1994

1-Ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(1-piperazinyl)quinolinea-3-car-boxylic acid-dextran was synthesized by the reaction of 1-ethyl-6-fluoro-1, 4-dihydro-4-oxo-7-(1-piperazinyl )quinoline-3-acryloyl chloride with dextran. Polymeric drug was tested for antimicrobial activity in vitro against ten species of microorganisms. Polymeric drug revealed good antibacterial activity against Bacillus subtillis ATCC 6633, Staphyloccus aureus ATCC 25923, Mycrobactertum phlei IFO 3158, Salmonella typhimurium KCTC 1925, Escherichia coli KCTC 1039, Escherichia coli ESS, Klebsiella puemouiae KCTC 1560 and Pseudomonas aeruginosa IFO 13130. Polymeric drug have no antimicrobial against Candida albicans ATCC 10231, but moderately active Micrococcus luteus ATCC 9341.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.646-651
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• 2005

The growth responses of Ruta chalepensis leaf-derived materials toward human intestinal bacteria were examined. The biologically active constituent of the R. chalepensis extract was characterized as quinoline-4-carboxaldehyde($C_{10}H_{7}NO$). The growth responses varied depending on the bacterial strain, chemicals, and dose tested. At 0.25 and 0.1 mg/disk, quinoline-4-carboxaldehyde strongly inhibited the growth of Clostridium perfringens and weakly inhibited the growth of Escherichia coli without any adverse effects on the growth of three lactic acid bacteria. Furthermore, at 0.05 and 0.025 mg/disk, this isolate showed moderate activity against C. perfringens. In comparison, chloramphenicol at as low as 0.01 mg/disk significantly inhibited the growth of all bacteria tested, and cinnamaldehyde at 0.25 mg/disk did not inhibit Bifidobacterium bifidum, B. longum, E. coli, and Lactobacillus acidophilus, with the exception of C. perfringens. The structure-activity relationship revealed that quinoline-3-carboxaldehyde had strong growth inhibition against C. perfringens, but quinoline, quinoline-3-carboxylic acid, and quinoline-4-carboxylic acid did not inhibit the growth of B. bifidum, B. longum, C. perfringens, E. coli, and L. acidophilus. These results indicate that the carboxyl aldehyde functional group of quinolines seems to be required for growth-inhibiting activity against C. perfringens, thus indicating at least one of the pharmacological actions of R. chalepensis leaf.

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.82-88
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• 2018

Stable slurries of YSZ in aqueous suspension with added polymer dispersants, namely, poly-methacrylic acid ammonium salt (PMMA), poly-acrylic acid (PAA) and poly-acrylic-co-maleic acid (PAMA), were mixed with the monomolecular dispersants citric acid and oxalic acid. The dispersion properties of the suspension were investigated using PSA, viscosity, sedimentation, and FT-IR. The polymer dispersants and monomolecular dispersants were attached to the YSZ surface by the carboxylic group, as shown by the FTIR results. A stabilized aqueous suspension was obtained when the polymer dispersant and citric acid were mixed and compared to the use of citric acid alone as a dispersant agent. When the polymer dispersant and citric acid were mixed and milled through attrition milling, there was a smaller particle size compared to when the polymer dispersant alone was used as a dispersant agent. This study determined that the particle size of the mixed dispersant was affected by the properties of the monomolecular dispersant and that the stability of the suspension was affected by the polymer dispersant. However, when slurries of YSZ were mixed with oxalic acid, the particle bridging behavior was the result of the high degree of viscosity and the small sedimentation height.