• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.873-881
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• 1994

The approximate rate and stoichiometry of the reaction of excess diisobutylaluminum hydride-dimethyl sulfide complex($DIBAH-SMe_2$) with organic compounds containing representative functional group under standardized conditions (toluene, $0{\circ}C$) were examined in order to define the reducing characterstics of the reagent and to compare the reducing power with DIBAH itself. In general, the reducing action of the complex is similar to that of DIBAH. However, the reducing power of the complex is weaker than that of DIBAH. All of the active hydrogen compounds including alcohols, amines, and thiols evolve hydrogen slowly. Aldehydes and ketones are reduced readily and quantitatively to give the corresponding alcohols. However, $DIBAH-SMe_2$ reduces carboxylic acids at a faster rate than DIBAH alone to the corresponding alcohols with a partial evolution of hydrogen. Similarly, acid chlorides, esters, and epoxides are readily reduced to the corresponding alcohols, but the reduction rate is much slower than that of DIBAH alone. Both primary aliphatic and aromatic amides examined evolve 1 equiv of hydrogen rapidly and are reduced slowly to the amines. Tertiary amides readily utilize 2 equiv of hydride for reduction. Nitriles consume 1 equiv of hydride rapidly but further hydride uptake is quite slow. Nitro compounds, azobenzene, and azoxybenzene are reduced moderately. Cyclohexanone oxime liberates ca. 0.8 equiv of hydrogen rapidly and is reduced to the N-hydroxylamine stage. Phenyl isocyanate is rapidly reduced to the imine stage, but further hydride uptake is quite sluggish. Pyridine reacts at a moderate rate with an uptake of one hydride in 48 h, while pyridine N-oxide reacts rapidly with consumption of 2 equiv of hydride for reduction in 6h. Similarly, disulfides and sulfoxide are readily reduced, whereas sulfide, sulfone, and sulfonic acid are inert to this reagent under these reaction conditions.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.531-537
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• 1992

The approximate rates and stoichiometry of the reaction of excess potassium 2-thexyl-1,3,2-dioxaborinane hydride(KTDBNH) with 55 selected compounds containing representative functional groups under standardized conditions (tetrahydrofuran, TEX>$0^{\circ}C$, reagent : compound=4 : 1) was examined in order to define the characteristics of the reagent for selective reductions. Benzyl alcohol and phenol evolve hydrogen immediately. However, primary, secondary and tertiary alcohols evolve hydrogen slowly, and the rate of hydrogen evolution is in order of $1^{\circ}$> $2^{\circ}$> $3^{\circ}$. n-Hexylamine is inert toward the reagent, whereas the thiols examined evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to give the corresponding alcohols. Cinnamaldehyde is rapidly reduced to cinnamyl alcohol, and further reduction is slow under these conditions. The reaction with p-benzoquinone dose not show a clean reduction, but anthraquinone is cleanly reduced to 9,10-dihydro-9,10-anthracenediol. Carboxylic acids liberate hydrogen immediately, further reduction is very slow. Cyclic anhydrides slowly consume 2 equiv of hydride, corresponding to reduction to the caboxylic acid and alcohol stages. Acid chlorides, esters, and lactones are rapidly and quantitatively reduced to the corresponding carbinols. Epoxides consume 1 equiv hydride slowly. Primary amides evolve 1 equiv of hydrogen readily, but further reduction is slow. Tertiary amides are also reduced slowly. Both aliphatic and aromatic nitriles consume 1 equiv of hydride rapidly, but further hydride uptake is slow. Analysis of the reaction mixture with 2,4-dinitrophenylhydrazine yields 64% of caproaldehyde and 87% of benzaldehyde, respectively. 1-Nitropropane utilizes 2 equiv of hydride, one for hydrogen evolution and the other for reduction. Other nitrogen compounds examined are also reduced slowly. Cyclohexanone oxime undergoes slow reduction to N-cyclohexylhydroxyamine. Pyridine ring is slowly attacked. Disulfides examined are reduced readily to the correponding thiols with rapid evolution of 1 equiv hydrogen. Dimethyl sulfoxide is reduced slowly to dimethyl sulfide, whereas the reduction of diphenyl sulfone is very slow. Sulfonic acids only liberate hydrogen quantitatively without any reduction. Finally, cyclohexyl tosylate is inert to this reagent. Consequently, potassium 2-thexyl-1,3,2-dioxaborinane hydride, a monoalkyldialkoxyborohydride, shows a unique reducing characteristics. The reducing power of this reagent exists somewhere between trialkylborohydrides and trialkoxyborohydride. Therefore, the reagent should find a useful application in organic synthesis, especially in the field of selective reduction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.288-298
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• 1992

Since the major important factors limiting plant growth and crop productivity are environmental stresses, of which low temperature is the most serious. It has been well known that many physiological processes are alterant in response to the environmental stress. With regard to the relationship between plant hormones and the regulation of chilling tolerance in rice seedlings, the major physiological roles of plant hormones: abscisic acid, ethylene and polyamines are evaluated and discussed in this paper. Rice seedlings were grown in culture solution to examine the effect of such plant hormones on physiological characters related to chilling tolerance and also to compare the different responses among tested cultivars. Intact seedlings about 14 day-old were chilled at conditions of 5$^{\circ}C$ and 80% relative humidity for various period. Cis-(＋)-ABA content was measured by the indirect ELISA technique. Polyamine content and ethylene production in leaves were determined by means of HPLC and GC respectively. Chilling damage of seedlings was evaluated by electrolyte leakage, TTC viability assay or servival test. Our experiment results described here demonstrated the physiological functions of ABA, ethylene, and polyamines related to the regulation of chilling tolerance in rice seedlings. Levels of cis-(＋)-ABA in leaves or xylem sap of rice seedlings increased rapidly in response to 5$^{\circ}C$ treatment. The tolerant cultivars had significant higher level of endogenous ABA than the sensitive ones. The ($\pm$)-ABA pretreatment for 48 h increased the chilling tolerance of the sensitive indica cultivar. One possible function of abscisic acid is the adjustment of plants to avoid chilling-induced water stress. Accumulation of proline and other compatible solutes is assumed to be another factor in the prevention of chilling injuies by abscisic acid. In addition, the expression of ABA-responsive gene is reported in some plants and may be involving in the acclimation to low temperature. Ethylene and its immediate precusor, 1-amincyclopropane-1-carboxylic acid(ACC) increased significantly after 5$^{\circ}C$ treatment. The activity of ACC synthase which converts S-adenosylmethionine (SAM) to ACC enhanced earlier than the increase of ethylene and ACC. Low temperature increased ACC synthase activity, whereas prolonged chilling treatment damaged the conversion of ACC to ethylene. It was shown that application of Ethphon was beneficial to recovering from chilling injury in rice seedlings. However, the physiological functions of chilling-induced ethylene are still unclear. Polyamines are thought to be a potential plant hormone and may be involving in the regulation of chilling response. Results indicated that chilling treatment induced a remarkable increase of polyamines, especially putrescine content in rice seedlings. The relative higher putrescine content was found in chilling-tolerant cultivar and the maximal level of enhanced putrescine in shoot of chilling cultivar(TNG. 67) was about 8 folds of controls at two days after chilling. The accumulation of polyamines may protect membrane structure or buffer ionic imbalance from chilling damage. Stress physiology is a rapidly expanding field. Plant growth regulators that improve tolerance to low temperature may affect stress protein production. The molecular or gene approaches will help us to elucidate the functions of plant hormones related to the regulation of chilling tolerance in plants in the near future.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.480-491
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• 2017

Fluorescent pseudomonads have been isolated from halophytes, mesophytes, and xerophytes of Pakistan. Among these, eight isolates, GS-1, GS-3, GS-4, GS-6, GS-7, FS-2 (cactus), ARS-38 (cotton), and RP-4 (para grass), showed antifungal activity and were selected for detailed study. Based on biochemical tests and 16S rRNA gene sequences, these were identified as strains of P. chlororaphis subsp. chlororaphis and aurantiaca. Secondary metabolites of these strains were analyzed by LC-MS. Phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine, Cyclic Lipopeptide (white line-inducing principle (WLIP)), and lahorenoic acid A were detected in variable amounts in these strains. P. aurantiaca PB-St2 was used as a reference as it is known for the production of these compounds. The phzO and PCA genes were amplified to assure that production of these compounds is not an artifact. Indole acetic acid production was confirmed and quantified by HPLC. HCN and siderophore production by all strains was observed by plate assays. These strains did not solubilize phosphate, but five strains were positive for zinc solubilization. Wheat seedlings were inoculated with these strains to observe their effect on plant growth. P. aurantiaca strains PB-St2 and GS-6 and P. chlororaphis RP-4 significantly increased both root and shoot dry weights, as compared with uninoculated plants. However, P. aurantiaca strains FS-2 and ARS-38 significantly increased root and shoot dry weights, respectively. All strains except PB-St2 and ARS-38 significantly increased the root length. This is the first report of the isolation of P. aurantiaca from cotton and cactus, P. chlororaphis from para grass, WLIP and lahorenoic acid A production by P. chlororaphis, and zinc solubilization by P. chlororaphis and P. aurantiaca.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.61-68
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• 2007

To develop rice (Oryza sativa L.) cultivars to be planted on salt-affected sites, cell lines with enhanced proline content and resistance to growth inhibition by Azetidine-2-carboxylic acid (AZCA), a proline analogue, were screened out among calli irradiated with gamma ray of 50, 70, 90, and 120 Gy. The calli had been derived from embryo culture of the cultivar Donganbyeo. Selected AZCA resistant lines that had high proline accumulation were used as sources for selection of NaCl resistant lines. To determine an optimum concentration for selection of NaCl resistant lines, Donganbyeo seeds were initially cultured on the media containing various NaCl concentrations (0 to 2.5%) for 40 days, and 1.5% NaCl concentration was determined as the optimum concentration. One hundred sixteen salt-tolerant (ST) lines were selected from bulked 20,000 seeds of the AZCA resistant $M_{3}$ seeds in the medium containing 1.5% NaCl. The putative 33 lines ($M_{4}$ generation) considered with salt-tolerance were further analyzed for salt tolerance, amino acid and ion contents, and expression patterns of the salt tolerance-related genes. Out of the 33 lines, 7 lines were confirmed to have superior salt tolerance. Based on growth comparison of the entries, the selected mutant lines exhibited greater shoot length with average 1.5 times, root length with 1.3 times, root numbers with 1.1 times, and fresh weight with 1.5 times than control. Proline contents were increased maximum 20%, 100% and 20% in the leaf, seed and callus, respectively, of the selected lines. Compared to control, amino acid contents of the mutants were 24 to 29%, 49 to 143%, 32 to 60% higher in the leaf, seed and callus, respectively. The ratio of $Na^{+}/K^{+}$ for most of the ST-lines were lower than that of control, ranging from 1.0 to 3.8 for the leaf and 11.5 to 28.5 for the root, while the control had 3.5 and 32.9 in the leaf and root, respectively. The transcription patterns for the P5CS and NHXI genes observed by RT-PCR analysis indicated that these genes were actively expressed under salt stress. The selected mutants will be useful for the development of rice cultivar resistant to salt stress.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.136-146
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• 1987

Flavor components were trapped by stimultaneous steam distillation-extraction method for investigating it in the bellflower roots and fractionated into four groups such as a neutral, a basic, a phenolic and an acidic fraction. An acidic fraction methylated with diazomethane solution and three others were analysed by GC and GC-MS equipping a fused silica capillary column, and S-containing compounds in these were detected with a flame photometric detector (FPD). The total of one hundred and three compounds from the bellflower roots were identified: they were 6 aliphatic hydrocarbons, 10 aromatic hydrocarbons, 2 terpene hydrocarbons, 12 alcohols, 8 terpene alcohols, 17 aldehydes, 3 terpene aldehydes, 5 ketones, 5 esters, 3 furans, 2 thiazoles, 2 lactones, 2 sulfides, 9 phenols, l2 carboxylic acids and 5 others. The greater part of the others except carboxylic acids were identified from a neutral fraction of which was assumed to be indispensable for the reproduction of bellflower root odor in a sensory evaluation. As a result of a sensory evaluation, 1-hexanal, trans-2-hexenal, 1-hexanol, cis-3-hexenol, trans-2-hexenol, 1-octen-3-ol and so forth identified in a neutral fraction were considered to be the key compounds of grass-like odor in the bellflower roots.

• Elastomers and Composites
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• v.40 no.3
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• pp.188-195
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• 2005

Chemical and physical changes and the contents of functional groups in the carbon black surface after the ozone treatment was investigated using elemental analysis, pH, tint strength, DBP, $N_2SA$, IA, and acid-base reaction. As the treatment time was increased, surface structure, particle size and surface area of carbon black did not change, while surface oxygen contents increased, and pH decreased and then saturated after $1{\sim}2$ hour. The contents of carboxylic, lactone, hydroxyl, and carbonyl groups were analyzed with four bases such as $NaHCO_3,\;Na_2CO_3,\;NaOH$, and $NaOC_2H_5$. Before oxidation, the carbonyl group was dominantly present on the surface, but by increasing the treatment time, the contents of the carboxylic and carbonyl groups increased to a saturated level after $1{\sim}2$ hour. Before and after the oxidation, the lactone and hydroxyl groups were nearly absent. These results showed that the reaction mechanism of carbon black and ozone is similar to that of ethylene and ozone. Weight of oxidized carbon black was increased after treating AIBN, while free radical was slightly decreased by ESR analysis. When carbon black was treated with organic compounds containing mercapto- groups, the results of ESR showed that free radical peak intensity was almost diminished compared to original carbon black.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.5
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• pp.441-446
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• 2014

Ursolic acid (UA), a type of pentacyclic triterpenoid carboxylic acid purified from natural plants, can promote skeletal muscle development. We measured the effect of resistance training (RT) with/without UA on skeletal muscle development and related factors in men. Sixteen healthy male participants (age, $29.37{\pm}5.14$ years; body mass index=$27.13{\pm}2.16kg/m^2$) were randomly assigned to RT (n=7) or RT with UA (RT+UA, n=9) groups. Both groups completed 8 weeks of intervention consisting of 5 sets of 26 exercises, with 10~15 repetitions at 60~80% of 1 repetition maximum and a 60~90-s rest interval between sets, performed 6 times/week. UA or placebo was orally ingested as 1 capsule 3 times/day for 8 weeks. The following factors were measured pre-and post-intervention: body composition, insulin, insulin-like growth factor-1 (IGF-1), irisin, and skeletal muscle strength. Body fat percentage was significantly decreased (p<0.001) in the RT+UA group, despite body weight, body mass index, lean body mass, glucose, and insulin levels remaining unchanged. IGF-1 and irisin were significantly increased compared with baseline levels in the RT+UA group (p<0.05). Maximal right and left extension (p<0.01), right flexion (p<0.05), and left flexion (p<0.001) were significantly increased compared with baseline levels in the RT+UA group. These findings suggest that UA-induced elevation of serum irisin may be useful as an agent for the enhancement of skeletal muscle strength during RT.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.320-324
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• 1995

Solubilization of microsomal ${\Delta}^{5}-3{\beta}$-hydroxy steroid acyl transfearse(${\Delta}^{5}-3{\beta}$-OH-SAT) of rat brain and its reconstitution into liposomes were investigated. Among the detergents utilized for the solubilization, deoxycholic acid was superior to Tween 80 or Triton X-100 for the reconstituted activity of ${\Delta}^{5}-3{\beta}$-OH-SAT. The enzyme activity was shown to be affected by the nature of phospholipids used for the preparation of the liposome. Phosphatidylcholines from egg yolk and soybean showed the highest activity of ${\Delta}^{5}-3{\beta}$-OH-SAT and phosphatidylethanolamine came next. However phosphatidylserine and phosphatidic acid showed a lower activity than those obtained before the reconstitution. This study suggests that the presence of quaternary ammonium salt or amine group in the phospholipids stimulates the activity of ${\Delta}^{5}-3{\beta}$-OH-SAT. However the presence of a carboxylic group or the absence of the amine group may have an inhibitory effect on the ${\Delta}^{5}-3{\beta}$-OH SAT.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.670-678
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• 2017

Self-emulsifiable polyethylene (PE) wax was prepared using acrylic acid grafted PE wax with potassium hydroxide and various emulsifiers for the economic production of PE wax emulsion. Modification reaction completion was confirmed that the peak from carbonyl group of acrylic acid disappeared and the new peak from carboxylic acid salts appeared in the FT-IR (Fourier transform infrared) spectrum data. Self-emulsifiable properties of the modified PE wax were investigated by the emulsion size and the stability of wax emulsion without any additional emulsifiers. According to self-emulsifiable properties, the emulsion size and stability were varied on the concentration and structure of the emulsifier. The greater emulsion concentration and hydrophilic poly(ethylene oxide) (PEO) characteristics of the emulsifier resulted in the smaller emulsion size and better emulsion stability. In addition, the use of emulsifiers mixture was more effective to obtain smaller size and uniform distribution of emulsion than that of single emulsifier in PE wax modification reaction. Especially, modified PE wax with OAE-5 and LAE-15 emulsifiers mixture shows excellent performance in terms of the smallest emulsion size ($4.34{\mu}m$) and emulsion stability.