• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1367-1374
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• 2005

Amino acid transporters play an important role in supplying nutrition to normal and cancer cells for cell proliferation. Amino acid transport system L is a major nutrient transport system responsible for the $Na^+$-independent transport of neutral amino acids including several essential amino acids. The system L is divided into two major subgroups, the L-tyre amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2). In the present study, we have examined the expression and functional characterization of system L amino acid transporters in FOB human osteoblast cells. RT-PCR and western blot analysis have revealed that the FOB cells expressed LAT1, LAT2 together with their associating protein 4F2hc. The uptakes of $[^{14}C]_L$-leucine by FOB cells are $Na^+$-independent and almost completely inhibited by system L amino acid transporter selective inhibitor, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). These results suggest that the transport of neutral amino acids including several essential amino acids for cellular nutrition into the FOB human osteoblast cells is mediated by system L amino acid transporters.

• Journal of Life Science
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• v.18 no.2
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• pp.148-153
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• 2008

Phytochrome double mutant (PhyAB) showed the delayed root gravitropic response compared to the wild type (WT) in Arabidopsis. After 8 hr of gravistimulation, the gravitropic response of mutant showed 48% of the WT. The delayed response started at 1.5 hr after gravistimulation. And we measured the ethylene production in the root segments of WT and mutant for 12 hr. Ethylene production of mutant decreased about 40% of the WT at 12 hr. This result suggested that the phytochrome might be linked with ethylene production in some way. Generally, ethylene inhibits the growth of plant organs including roots. We measured the root growth rate in the presence of ACC (1-aminocyclopropane-1-carboxylic acid), a precursor of ethylene. And WT showed the inhibition of root growth with ACC, but mutant did not show the inhibition as WT did. To confirm the relationship between the ethylene and gravitropic response, we measured the gravitropic response with ACC. In the presence of $10^{-6}$ M ACC, WT showed the 37.4% inhibition compared to the control (no ACC), whereas mutant showed the only 6.6% inhibition of control (no ACC). This research suggested the relationship between phytochrome and gravitropic response through an ethylene production.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.301-306
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• 2001

Column tests were conducted to investigate the optimal condition of surfactant solution pH that can affect the removal efficiency in surfactant-assisted remediation. Toluene and 1,2,4-trichlorobenzene were chosen as the model hydrophobic substances. Two Iowa soils, Fruitfield sand and Webster clay loam, were leached with solutions of 4%(v/v) sodium diphenyl oxide disulfonate (DOSL, trade name Dowfax 8390), or 4%(v/v) trideceth-19-carboxylic acid (TDCA, trade name Sandopan JA36), or 4% (v/v) octylphenoxypoly ethoxyethanol (OPEE, trade name Triton X100). The test results revealed that a maximum removal of toluene and 1,2,4-trichlorobenzene was obtained at pH 10 of surfactant solution, and maximum recoveries of added toluene (94%) or 1 ,2,4- trichlorobenzene (97 %) were obtained for DOSL surfactant solution in Fruitfield sandy soil column. Increased removal efficiency by pH control of both toluene and 1,2,4trichlorobenzene was 16% and 20% for DOSL with Fruitfild sandy soil, respectively. In addition, the maximum recoveries of added toluene or I ,2,4-trichlorobenzene were 89% and 93% for DOSL surfactant solution in Webster clay loam soil column. The maximum increase of toluene and 1,2,4-trichlorobenzene removal was 26% and 19% for DOSL with Webster clay loam soil, respectively. These experimental results indicate that maintaining a high pH surfactant solution in surfactant-assisted remediation is desirable for efficient removal of NAPLs from contminated soils.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.195-199
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• 1998

AH alkalophilic Bacillus SP. AIk-7, isolated from soil, produced ethylene. The characteristics of this microorganism is the ability to grow well under the alkaline condition, at pH 10.3. This strain is similar to Bacillus alkalophilus in terms of morphological, physiological and biological characteristics. In observation of relationship of cell growth and ethylene production according to incubation times, the ethylene synthesis mostly occur from the late exponential phase to the death phase of growth. The purpose of this paper is to study the effects of various substrates on the biosynthesis of ethylene in the intact cell and the cell-free system by the Bacillus sp. AIk-7. In both intact cell and cell-free extract, optimum conditions for ethylene production was achieved at pH 10.3 and 3$0^{\circ}C$. Ethylene was effectively produced from L-Met and 1-aminocyclopropane-1-carboxylic acid (ACC). In this case, ACC as the substrate on ethylene production were two fold higher than L-met at each concentration of substrates. On the other hand, the cell-free ethylene-forming system was used as a tool for the elucidation of the biochemical reaction involved in the formation of ethylene by Bacillus sp. AIk-7. Ethylene production in the cell-free system required the presence of manganese and cobalt ion to be stimulated a little. The result obtained in this work suggests that L-met and ACC may be a precursor more directly related to bacterial ethylene production than any other substrates tested.

• Journal of Plant Biology
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• v.37 no.4
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• pp.445-452
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• 1994

Effects of methyl jasmonate (MeJA) on ethylene production in mungbean (Phaseolus radiatus L.) hypocotyl and leaf segments were studied. Ethylene production in mungbean hypocotyl segments was decreased in proportion to MeJA concentrations and $450\;\mu\textrm{M}$ of MeJA showed 50% inhibitory effect. This inhibitory effect appeared after 3 h of incubation period and continued for 24 h. Inhibition of ethylene production by MeJA was due to the decrease in 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity. However, MeJA treatment had no effect on ACC content and ACC synthase activity. MeJA also inhibited auxin-induced ethylene production in hypocotyls. To investigate the mechanisms of the inhibitory effect of MeJA on the auxin-induced ethylene production, ACC synthase and ACC oxidase activity were examined after MeJA treatment. MeJA decreased the ACC content and ACC synthase activity as weD as ACC oxidase activity in the auxin-treated tissue. These results suggest that the inhibition of MeJA on auxin-induced ethylene production is not due to the direct inhibitory effect of MeJA on the ACC synthase, but to the inhibition of the ability of IAA to promote the synthesis of ACC synthase. In contrast, ethylene production from the detached mungbean leaves was stimulated by MeJA. The rate of ethylene production increased approximately 65% over the control after 12 h of incubation period by $4.5\;\mu\textrm{M}$ MeJA. When MeJA was applied to detached leaves along with IAA, the effect of MeJA appeared to be additive. In an effort to elucidate mechanisms of MeJA action on auxin-induced ethylene production in the leaf tissue, enzyme activities of ACC synthase and ACC oxidase were examined. MeJA stimulated ACC oxidase activity but did not affect ACC synthase activity in leaf tissue. Together, these results suggest that MeJA plays different roles in the ethylene production in the different mungbean tissues.issues.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.151-156
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• 2010

Investigation of secondary bioactive metabolites from the fruiting bodies of Lactarius hatsudake led to the isolation of four azulene derivatives by means of repeated column chromatography and preparative HPLC, and they were identified as 1-formyl-4-methyl-7-isopropyl azulene (1), lactaroviolin (2), 4-methyl-7-isopropyl-azulene-1-carboxylic acid (3), and 1-formyl-4-methyl-7-(1-hydroxy-1-methylethyl) azulene (4) by their physico-chemical properties and spectroscopic analysis. The isolated compounds were evaluated for the effects on modulation of cytokines in natural killer cell line (NK92 cells). Compounds 1 and 4 strongly inhibited IFN-$\gamma$ production in a dose-dependent manner, corresponding to 101.3 % and 92.7 % inhibition at 400 ${\mu}M$, and 11.9 % and 24.1 % at 100 ${\mu}M$, respectively, whereas compounds 2 and 3 showed weak inhibitory effect on INF-$\gamma$ production, corresponding to 45.9 % and 18.0 % inhibition at 400 ${\mu}M$.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.26-32
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• 2001

[ ${\alpha},{\beta}$ ]-Unsaturated carboxamides 12 with trifluromethylated dihydro-1,4-dithiins were synthesized for the purpose of development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}$-ketoester 4 followed by tile reaction with 1,2-ethanedithiol gave intermediate 1,4-dithiane 9. Without purification of 9 substitution of hydroxy by chlorine followed by dehydrochlorination in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-dithiin ethyl ester 7. Activation of the hydroxy of the carboxylic acid 10 obtained from the hydrolysis of 7 and then reacted with various amines gave the corresponding trifluoromethylated dihydro-1,4-dithiin carboxamides. Antifungal screening (in vivo) against typical plant diseases, Rice Blast, Rice Sheath Blight, Cucumber Gray Mold, Tomato Late Blight, Wheat Leaf Rust, and Barley Powdery Mildew of the synthesized compounds was carried out. As a result, most of the compounds shlowed weak antifungal activities and some compounds in which isopropyl group was substituted in meta of the phenyl showed antifungal activity (99%) at 250 ppm against the disease Wheat Leaf Rust.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.257-264
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• 2017

Pseudomonas veronii MS1 and P. migulae MS2 have several mechanisms of copper resistance and plant growth promoting capability, and also can alleviate abiotic stress in plant by hydrolysis of a precursor of stress ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC) by ACC deaminase. In 4-week pot test for tomato growth in soil contained 700 mg/kg Cu, inoculation of MS1 and MS2 significantly increased root and shoot lengths, wet weight and dry weight of tomato plants compared to those of uninoculated control. The inoculated tomato plants contained less amounts of proline that can protect plants from abiotic stress, and malondialdehyde, an oxidative stress marker than those of control. ACC synthase genes, ACS4 and ACS6, and ACC oxidase genes, ACO1 and ACO4, both involved in ethylene synthesis, were strongly expressed in Cu stressed tomato, whereas significantly reduced in tomato inoculated with MS1 and MS2. Also, a gene encoding a metal binding protein metallothionein, MT2 showed similar expression pattern with above genes. All these results indicated that these rhizobacteria could confer Cu resistance to tomato plant under Cu stress and allowed a lower level of Cu stress and growth promotion.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1299-1309
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• 2019

As an opportunistic bacterial pathogen, Pseudomonas aeruginosa PAO1 contains two phenazine-producing gene operons, phzA1B1C1D1E1F1G1 (phz1) and phzA2B2C2D2E2F2G2 (phz2), each of which is independently capable of encoding all enzymes for biosynthesizing phenazines, including phenazine-1-carboxylic acid and its derivatives. Other previous study reported that the RpoS-deficient mutant SS24 overproduced pyocyanin, a derivative of phenazine-1-carboxylic acid. However, it is not known how RpoS mediates the expression of two phz operons and regulates pyocyanin biosynthesis in detail. In this study, with deletion of the rpoS gene in the $PA{\Delta}phz1$ mutant and the $PA{\Delta}phz2$ mutant respectively, we demonstrated that RpoS exerted opposite regulatory roles on the expression of the phz1and phz2 operons. We also confirmed that the phz1 operon played a critical role and especially biosynthesized much more phenazines than the phz2 operon when the rpoS gene was knocked out in P. aeruginosa. By constructing the translational reporter fusion vector lasR'-'lacZ and the chromosomal fusion mutant $PA{\Delta}lasR::lacZ$, we verified that RpoS deficiency caused increased expression of lasR, a transcription regulator gene in a first quorum sensing system (las) that activates overexpression of the phz1 operon, suggesting that in the absence of RpoS, LasR might act as an intermediate in overproduction of phenazine biosynthesis mediated by the phz1 operon in P. aeruginosa.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.506-514
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• 2020

4-Hydroxybenzyl alcohol (4-HB alcohol) is one of the major active components of Gastrodia elata Blume, with beneficial effects on neurological disorders such as headache, convulsive behavior, and dizziness. Here, we developed a metabolically engineered Corynebacterium glutamicum strain able to produce 4-HB alcohol from 4-hydroxybenzoate (4-HBA). First, the strain APS963 was obtained from the APS809 strain via the insertion of aroK from Methanocaldococcus jannaschii into the NCgl2922-deleted locus. As carboxylic acid reductase from Nocardia iowensis catalyzes the reduction of 4HBA to 4-hydroxybenzaldehyde (4-HB aldehyde), we then introduced a codon-optimized car gene into the genome of APS963, generating the GAS177 strain. Then, we deleted creG coding for a putative short-chain dehydrogenase and inserted ubiCpr encoding a product-resistant chorismate-pyruvate lyase into the pcaHG-deleted locus. The resulting engineered GAS355 strain accumulated 2.3 g/l 4-HB alcohol with 0.32 g/l 4-HBA and 0.3 g/l 4-HB aldehyde as byproducts from 8% glucose after 48 h of culture.