• Journal of Life Science
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• v.23 no.3
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• pp.368-376
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• 2013

The optimal condition for Morus alba cv was an MS culture medium at $27^{\circ}C$ for 20 days. Cheongmoknosang callus showed inhibitory activity against Helicobacter pylori at 1.05 g of wet weight of the cultured callus. The callus formation of Morus alba cv. Cheongmoknosang was influenced by naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D), 6-benzylaminopurine (BA) and kinetin at concentrations of 2 mg/l. The growth rate of callus was higher than it was when these hormones were mixed with a single hormone. Thus, the optimal condition for direct callogenesis was to incubate with mixture (2,4-D/NAA) of 2 mg/l concentration at $27^{\circ}C$ for 20 days. Moreover, the optimal culture condition of the biomass in the mass production of inhibitory compounds against Helicobacter pylori from Morus alba cv. Cheongmoknosang callus was to incubate in an MS broth (each concentration 1 mg/l of 2,4-D and BA). When Morus alba cv. Cheongmoknosang callus were incubated for 20 days in a bioreactor, Helicobacter pylori inhibition of callus extracts was the highest at a clear zone of 16 mm.

• Korean Journal of Plant Resources
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• v.29 no.1
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• pp.39-45
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• 2016

Pink Rot on melon and White Stain Symptom on grape are caused by Trichothecium roseum, one of the most important diseases of grape and melon. These diseases have been occurred in national-wide in Korea and causes irreversible damage on the grape and the melon at harvest season. This research presents the evaluation of the capacity of Bacillus subtillis HK2 to protect both melon and grape against T. reseum and establishes its role as a biocontrol agent. In this study, we isolated a Bacillus strain HK2 from rhizosphere soil, identified it as Bacillus subtillis by 16S rRNA analysis and demonstrated its antifungal activity against T. roseum. Under I-plate assay it was observed that the effect of hyphal growth inhibition was not due to production of volatile compounds. The optimum culture condition of HK2 was found at 30℃ and initial pH of 7.0. Application of HK2 culture suspension reduced 90.2% of white stain symptom on grape as compared to control, resulting in greater protection to grape against T. roseum infestation. Butanol extract of HK2 culture purified using flash column chromatography. The antifungal material was a polar substance as it showed antifungal activity in polar elute. Therefore, our results indicated a clear potential of B. subtilis HK2 to be used for biocontrol of Pink rot in melon and white stain symptom on grape caused by T. roseum.

• Journal of the Korean Chemical Society
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• v.43 no.4
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• pp.438-446
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• 1999

The optimum analytical method of aldehydes, ozone by-products, was established by reverse phase liquid chromatography. Six aldehydes including formaldehyde, acetaldehyde, acrolein, propionaldehyde, butylaldehyde and benzaldehyde, and one ketone including acetone were selected as aldehyde test samples through preliminary experiments. Such analytical conditions as the pH of citrate buffer solution, reaction temperature, reaction time, and concentration of DNPH, the component and composition of desorption solvent were optimized. As the result, pH 3.0 of citrate buffer solution, 40$^{\circ}C$ of reaction temperature, 15 minutes of reaction time, and 0.012% of DNPH concentration were chosen as optimum conditions. Aldehydes-DNPH derivatives in water were concentrated on $C_18$ Sep-Pak cartridge and followed by elution of their derivatives fraction with THF/ACN(70/30) mixture, and showed recoveries of the range from 87 to 107%. Separation condition on Nova-Pak $C_18$ column with low pressure gradient elution from ACN/MeOH/water(30/10/60) of an initial condition to 80% ACN of a final condition was found to give a good resolution within 20 minutes of run time. 86% to 103% of recovery for aldehydes using this method was similar to that for aldehyde using EPA Method 554 which is ranged from 84% to 103%.

• Journal of the Korean Electrochemical Society
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• v.7 no.4
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• pp.183-188
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• 2004

In order to develop polymer electrolyte for lithium/sulfur batteries, highly microporous P(VdF-HFP) membranes were prepared by phase inversion method. Porous structure was controlled by extracting NMP with mixture of deionized water and methanol. Porous structure of the membranes was observed with SEM. Polymer electrolytes were prepared by soaking the porous membranes in 1M $LiCF_3SO_3-TEGDME/EC$. The ionic conductivity of polymer electrolyte was found to be at high as $2\times10^{-3}S/cm$ when the polymer membrane extracted by $80\%$ methanol was used. The microporous polymer electrolyte optimized in this work displayed high ionic conductivity, uniform pore size, low interfacial resistance and stable ionic conductivity with storage time. The ionic conductivity of polymer electrolytes was measured with various lithium salts, and the conductivity showed $3.3\times10^{-3}S/cm$ at room temperature when $LiPF_6$ was used as a lithium salt.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.359-363
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• 2009

This study was performed to establish a rapid and simple analytical method for niacin (nicotinic acid and nicotinamide) using HPLC. A pretreatment method for the extraction and clean-up of niacin in infant formula sample and an instrumental condition for HPLC were optimized. Niacin was extracted by 5 mM hexanesulfonate with ultrasonication for 30 min. For the clean-up of the sample, the extract was applied to a HLB cartridge, and then niacin was eluted from the cartridge using 5 mL of 80% methanol after washing with 5 mL of n-hexane. The total recoveries were $83{\sim}104%$ and relative standard deviation were in the range of $1.5{\sim}3.5%$ during the extraction and clean-up process. Niacin was determined by gradient elution with sodium hexanesulfonate/methanol buffer as a mobile phase and a photodiode array detector (260 nm). It showed a high linearity between the content of niacin and the peak area ($r^2$=1.000) in the range of $0.02{\sim}10.0$ mg/L of nicotinic acid and nicotinamide. The detection limit was 0.02 mg/L (0.2 mg/kg in the sample). The method was successfully applied for the determination of niacin in infant formula. Total niacin contents were in the range of $53.5{\sim}140.3$ mg/kg.

• KSBB Journal
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• v.24 no.2
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• pp.163-169
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• 2009

Lovastatin (also known as Mevinolin, Mevacor, and Monacolin K), an inhibitor of the HMG-CoA reductase produced by Aspergillus terreus and other fungi, is used to reduce serum cholesterol levels in human beings. It is derived biosynthetically from two polyketides. One of these is a nonaketide that undergoes cyclization at a hexahydronaphthalene ring system, and the other is a simple diketide, 2-methylbutyrate. Two primer pairs were designed based on the amino acid sequences of lovastatin polyketide synthase and lovastatin diketide synthase for the PCR screening of lovastatin-producing strains. Among the seven selected strains, SJ-2 evidenced the highest level of lovastatin production in both liquid and solid cultures. Soybeans with SJ-2 were treated via 1 hour of heat shock at $30^{\circ}C$ for the mass production of lovastatin. The heat-treated soybeans were inoculated on rice bran and the koji extract was obtained after 15 days of incubation. It yielded the highest level of lovastatin production among the strains, and also evidenced 75% inhibition activity against HMG-CoA reductase. We developed an efficient PCR screening method for lovastatin-producing strains, using lovastatin biosynthesis genes.

• Journal of Radiation Protection and Research
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• v.17 no.2
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• pp.25-35
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• 1992

To evaluate tritium level in some environmental samples, tissue-free water tritium (TFWT) and tissue-bound tritium (TBT) were analyzed in rices, chinese cabbages and pine needles collected at 12 locations in Korea. The TFWT was recovered by freeze-drying of the samples and the TBT was obtained in the form of water by combustion of the dried samples. Tritium was measured by liquid scintillation counter. The concentrations of TFWT were in the range of $0.96{\sim}3.96 Bq/1,\; 0.83{\sim}3.40 Bq/1\;and\;1.02{\sim}3.01 Bq/1$ in rices, chinese cabbages and pine needles, respectively. The mean specific activity ratios (TBT/TFWT) were 0.94, 1.71 and 1.39 in rices, chinese cabbages and pine needles, respectiviely. This excess TBT in the samples may be attributed to the fact that the residence time of TBT in the plant is longer than that of TFWT. The specific activity ratio depends on the plant species, the exposed time to tritiated atmosphere, atmospheric moisture, temperature and diffusion factor.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.192-200
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• 1984

Total lipid contents in rice bran for Poong-San(Tongil) and Dong-Jin(Japonica) were 16.13% and 16.97%, respectively. Neutral lipids for Pong-San(75.20%) were slightly higher than those for Dong-Jin(73.69%), whereas contents of glycolipid for Poong-San(16.71%) were lower than those for Dong-Jin(22.80%). Contents of phospholipid in Poong-San(8.09%) were much higher than those in Dong-Jin(3.51%). Acid, peroxide and thiobarbituric acid value of total lipids extracted from rice bran of Poong-San were slightly lower than those of Dong-Jin. Iodine value showed the reverse trend. The neutral lipids were fractionated and identified as hydrocarbon, esterified sterol, triglyceride, free fatty acid, free sterol, diglyceride and monoglyceride. Triglyceride contents were less than common edible oils, but diglyceride and monoglyceride contents were higher. Among the glycolipids contained in the polar lipids, esterified sterylglycoside(11.46%) was the most abundant. Of the phospholipids, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl choline were the major components. Main fatty acids in the total lipids, three lipid components and stepwise eluted individual lipids were olelic acid, linoleic acid and palmitic acid. The fatty acid composition of the neutral lipids was similar to that of the total lipids. In glycolipids, the content of linoleic acid was higher than that of oleic acid, and palmitic acid was predominant in the fatty acid composition of the esterified sterylglycoside.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.298-303
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• 1979

The composition of the neutral lipids in the free and bound lipids from four varieties of experimentally cultivated potatoes were identified and quantified by thin layer- and gas-liquid chromatographies. The results were summarized as follows ; 1. The neutral lipids contained in the free and bound lipids were fractionated and identified as esterified sterol, triglyceride, diglyceride, free fatty acid, and free sterol, of which triglyceride and esterified sterol were most abundant. Meanwhile, the triglyceride and esterified sterol contents in the free lipid to the total lipid quantity were 10 and 2.7 % respectively, approximately 3 times higher than the 3.0 and 0.8 % contained in the bound lipid. 2. The fatty acid composition of the neutral lipids in the free and bound lipids was the same as that of the total free and bound lipids. The only difference was that content of saturated fatty acid was lower rate in the neutral lipid of the free lipid than in the total free lipid, whereas the unsaturated fatty acid was more abundant in the neutral lipid of the free lipid. Fatty acid composition of individual neutral lipid was of almost the same pattern as that of the total neutral lipid.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.291-297
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• 1979

The experimentally cultivated potatoes of 4 varieties, Irish Cobbler, Warba, Shimabara, and Saco were dried in a frozen state, powdered subsequently and subjected to the extraction of free and bound lipids. Constituents of the prepared lipids were fractionated, quantified, and compared by the methods of column and gas-liquid chromatographies. The results were summarized as follows : 1. The total crude lipid content in potato on a dry weight basis was 0.57 % of which 0.2 % was free lipid and 0.37 % was bound lipid. 2. The neutral lipid content in the free lipid was 14.9 %, approximately 3 times as much as the 4.5 % contained in the bound lipid, whereas the glycolipid content in the free lipid was 15.1 %, slightly less than 22.2 % contained in the bound lipid. However, the phospholipid content was 33.9 % in the bound lipid, approximately 4.5 times as much as the 7.2 % contained in the free lipid. This fact revealed that the bound lipid consisted mainly of polar lipid, while the free lipid consisted of neutral lipids, glycolipids and phospholipids in about the same proportion. 3. The main fatty acids constituting more than 90 % in the free and bound lipids were linoleic, palmitic and linolenic acids. The content of the saturated fatty acid was slightly less in the free lipid than in the bound lipid, whereas the unsaturated fatty acids were more abundant in the free lipid.