• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.235-241
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• 2003

For the biological control of Phytophthora blight of red-pepper caused by Phytophthora capsici, an antibiotic-producing plant growth promoting rhizobacteria (PGPR) Bacillus sp. KL 39 was selected from a local soil of Kyongbuk, Korea. The strain KL 39 was identified as Bacillus megaterium by various cultural, biochemical test and API and Microlog system. B. megaterium KL 39 could produce the highest antifungal antibiotic after 40 h of incubation under the optimal medium which was 0.4% fructose, 0.3% yeast extract, and 5 mM KCl at 30 C with initial pH 8.0. The antifungal antibiotic KL 39 was purified by Diaion HP-20 column, silica gel column, Sephadex LH-20 column, and HPLC. Its RF value was confirmed 0.32 by thin-layer chromatography with Ethanol:Ammonia:Water = 8:1:1. The crude antibiotic KL39 was active against a broad range of plant pathogenic fungi, Rhizoctonia solani, Pyricularia oryzae, Monilinia fructicola, Botrytis cinenea, Alteranria kikuchiana, Fusarium oxysporum and Fusarium solani. The purified antifungal antibiotic KL39 had a powerful biocontrol activity against red-pepper phytophthora blight disease with in vivo pot test as well as the strain B. megaterium KL 39.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.4
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• pp.490-497
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• 2010

A chitinolytic bacterium having a strong antagonistic activity against various pathogens including Phytophtora capsici was isolated from rhizosphere soil, and identified as Lysobacter enzymogenes (named as LE429) based on 16S rRNA gene sequence analysis. This strain produced a number of substances such as chitinase, ${\beta}-1$, 3-glucanase, lipase, protease, gelatinase and an antibiotic compound. This antibiotic compound was purified by diaion HP-20, sephadex LH-20 column chromatography and HPLC. The purified compound was identified as phenylacetic acid by gas chromatography-electron ionization (GC-EI) and gas chromatography-chemical ionization (GC-CI) mass spectrometry. In field experiment, pepper plants were treated by the strain LE429 culture (CB), neem oil solution (NO), combination (CB+NO) or control (CON). Plant height and number of branches, flowers and pods of pepper plant in CB treatment were generally highest, and followed by CB+NO, CON and NO. The fungal pathogens were strongly inhibited, while several insect pests were discovered in CB treatment. Any insect pests were not found, while all fungal pathogens tested were not suppressed in NO treatment. However, in CB+NO treatment, non incidence of fungal pathogens and insect pests were found. The strain LE429 producing secondary metabolites with neem oil should be a potential agent to control fungal diseases and insect pests.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.195-202
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• 2002

The cytotoxic, mutagenic and antimutagenic activities against chemical direct mutagens such as mitomycin C, 4-nitroquinoline-N-oxide, 2,4,7-trinitro-9-fluorenone of the 70% ethanol extracts of 29 colored rice varieties and chuchung as a control were examined. The results obtained using authentic alkaline phosphatase activity as a growth representative of the indicator cell E. coli PQ 37 demonstrated that the extracts of 13 kinds of colored rice varieties including Jumlalocal and Jumlalocal-1 showed strong toxic effect on the cell growth. However the extracts of DK 1, SC-5, LK 1A-2-12-1-1 and wx 139-3-64-20-3-1 seemed to have stimulatory effects on the cell growth. The mutagenicity and antimutagenicity of the colored rice varieties were screened using SOS chromotest. The mutagenic activity was detected from Jumalocal-1, IR 17491-5-4-3-3 and Jumlalocal. On the contrary, 7 samples including LK 1-3-6-12-1-1, Parnkhari 203, Jumlalocal, wx 139-3-64-20-3-1, Muthumanikam, HP 883-1-1-1-B-1-1 and Jumlalocal-1 were shown to have antimutagenic acitivities against the chemical direct mutagens used in this study.

• Journal of Life Science
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• v.30 no.5
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• pp.476-482
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• 2020

In rice agriculture, Eleocharis kuroguwai Ohwi (olbanggae) is a target for herbicidal intervention as a problem weed although it has also long been used clinically as a traditional medicine for jaundice, fever, and blood flow. E. kuroguwai has been evaluated in many clinical trials, but its molecular biological advantages are still unknown. Here, we investigate the anti-inflammatory effects of E. kuroguwai 80% ethanol extracts by screening NO production in LPS-induced macrophage activation. To find the most effective fractions, we partitioned five sub-fractions using HP20 column chromatography, namely 20%, 40%, 60%, 80%, and 100%. Of these, the 60% and 80% sub-fractions were found to significantly inhibit NO production; there were no toxicological effects at any concentration. In addition, the 80% sub-fraction inhibited significantly the iNOS and the mRNA of the pro-inflammatory mediators IL-6, TNF-α, and IL-1β by inhibiting the phosphorylation of JNK and ERK pathways associated with MAPKs signaling. Our results suggest that the 80% E. kuroguwai sub-fraction has the most significant anti-inflammatory effects of inhibiting iNOS and pro-inflammatory mediators and suppressing the phosphorylation of JNK and ERK. Therefore, the 80% sub-fraction of E. kuroguwai extract may be a therapeutic candidate for inflammatory diseases associated with the overexpression of MAPKs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1090-1099
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• 2015

Among the four different parts of mulberry (Morus alba L.) tree, ethanol extract of Morus root bark showed the highest ${\alpha}$-glucosidase inhibitory activity ($IC_{50}=12.01{\mu}g/mL$). Bioassay-guided fractionation of the ethanolic extract of root bark by Diaion HP-20, silica gel, ODS-A, and Sephadex LH-20 column chromatographies led to the isolation of four compounds, including Compound (Comp.) 1 ($IC_{50}=5.22{\mu}g/mL$), Comp. 2 ($IC_{50}=1.78{\mu}g/mL$), Comp. 3 ($IC_{50}=2.94{\mu}g/mL$), and Comp. 4 ($IC_{50}=1.54{\mu}g/mL$) with strong ${\alpha}$-glucosidase inhibitory activities. Their chemical structures were elucidated as morusin (Comp. 1), kuwanon H (Comp. 2), chalcomoracin A (Comp. 3), and chalcomoracin B (Comp. 4) by UV and NMR spectral analyses. These results suggest that prenylflavonoid and mulberrofuran of Morus root bark may be useful as potential therapeutic agents for diabetes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.517-531
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• 1999

This paper presents the development of the 2-mode variable gain high power amplifier for a transmitter of INMARSAT-M operating at L-band(1626.5-1646.5 MHz). This SSPA(Solid State Power Amplifier) is amplified 42 dBm in high power mode and 36 dBm in low power mode for INMARSAT-M. The allowable error sets +1 dBm of an upper limit and -2 dBm of a lower limit, respectively. To simplify the fabrication process, the whole system is designed by two parts composed of a driving amplifier and a high power amplifier, The HP's MGA-64135 and Motorola's MRF-6401 are used for driving amplifier, and the ERICSSON's PTE-10114 and PTF-10021 are used the high power amplifier. The SSPA was fabricated by the circuits of RF, temperature compensation and 2-mode gain control circuit in aluminum housing. The gain control method was proposed by controlling the voltage for the 2-mode. In addition, It has been experimentally verified that the gain is controlled for single tone signal as well as two tone signals. The realized SSPA has 42 dB and 36 dB for small signal gain within 20 MHz bandwidth, and the VSWR of input and output port is less than 1.5:1 The minimum value of the 1 dB compression point gets 5 dBm for 2-mode variable gain high power amplifier. A typical two tone intermodulation point has 32.5 dBc maximum which is single carrier backed off 3 dB from 1 dB compression point. The maximum output power of 43 dBm was achieved at the 1636.5 MHz. These results reveal a high power of 20 Watt, which was the design target.the design target.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.178-182
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• 1992

For an industrial-scale purification and production of cephalosporin C from a culture broth of Ceplzalos#mium nmemonium CSA-2.8A3 mutant, ultrafiltration, column chromatography, reverse osmosis, and spray drying were empolyed. Above 90% of yield and high purity of cephalosporin C were obtained through WA-30, HP-20, XAD-2000 and SK-1B column chromatographies. Especially, in the tendom operation of the columns, the recovery yield was increased up to 96%. The purified cephalosporin C was stable at $4^{\circ}C$ and in acidic condition, while it was unstable at room temperature and in alkaline condition at pH above 8.0. Cephalosporin C powder or a final product prepared by spray drying contained 85.554 of sodium cephalosporin C, 6.3%' of water, 4.63% of free $Na^+$ ions. and traces of metal ions.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.633-636
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• 2007

The objective of this study is to measure backscattering coefficients of paddy rice using L, C, X-bands scatterometer system during a rice growth period. The measurement was conducted at an experimental field located in National Institute of Agricultural Science and Technology (NIAST), Suwon, Korea. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer (20MHz ${\sim}$ 20GHz), RF cables, and a personal computer that controls frequency, polarization and data storage. The scatterometer system is calibrated using a calibration kit (3.5mm, 85052D). The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ for four polarization (HR, VV, HV, VH), respectively, and compared with rice growth data such as plant height, stem number, biomass, dry weight and LAI that were collected at time of each scatterometer measurement simultaneously.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.220-225
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• 2007

In order to develop a potent antidandruffy agent from medicinal plants, various extracts of medicinal plants and herbs were prepared and investigated its antifungal activity against Malassezia furfur. Among 85 kinds of the secondary screened medicinal plants and herbs, water extract of Chrysanthemum zawadskii had the highest antifungal activity against dandruffy-producing Malassezia furfur. The antifungal compound was also maximally extracted when the powder of Chrysanthemum zawadskii was treated with water at $50^{\circ}C$ for 6 hours. The antifungal compound from Chrysanthemum zawadskii was partially purified by silica gel column chromatography and the partial purified compound was soluble at $70^{\circ}C$ for 20 min and pH $3.0{\sim}9.0$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.3
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• pp.182-189
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• 2011

In this work, a tunneling field-effect transistor (TFET) based on heterojunctions of compound and Group IV semiconductors is introduced and simulated. TFETs based on either silicon or compound semiconductors have been intensively researched due to their merits of robustness against short channel effects (SCEs) and excellent subthreshold swing (SS) characteristics. However, silicon TFETs have the drawback of low on-current and compound ones are difficult to integrate with silicon CMOS circuits. In order to combine the high tunneling efficiency of narrow bandgap material TFETs and the high mobility of III-V TFETs, a Type-I heterojunction tunneling field-effect transistor (I-HTFET) adopting $Ge-Al_xGa_{1-x}As-Ge$ system has been optimized by simulation in terms of aluminum (Al) composition. To maximize device performance, we considered a nanowire structure, and it was shown that high performance (HP) logic technology can be achieved by the proposed device. The optimum Al composition turned out to be around 20% (x=0.2).