• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1127-1132
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• 2012

Nargenicin $A_1$ is a 28-membered polyketide macrolide, with antibacterial activity against methicillin-resistant Staphylococcus aureus, produced by Nocardia sp. CS682. In this study, the production of nargenicin $A_1$ was improved by enhancing the supply of different biosynthetic precursors. In Nocardia sp. CS682 (KCTC11297BP), this improvement was ~4.62-fold with the supplementation of 30 mM methyl oleate, 4.25-fold with supplementation of 15mM sodium propionate, and 2.81-fold with supplementation of 15 mM sodium acetate. In Nocardia sp. metK18 and Nocardia sp. CS682 expressing S-adenosylmethionine synthetase (MetK), the production of nargenicin $A_1$ was improved by ~5.57-fold by supplementation with 30 mM methyl oleate, 5.01-fold by supplementation with 15 mM sodium propionate, and 3.64-fold by supplementation with 15 mM sodium acetate. Furthermore, supplementing the culture broth of Nocardia sp. ACC18 and Nocardia sp. CS682 expressing the acetyl-CoA carboxylase complex (AccA2 and AccBE) with 30 mM methyl oleate, 15 mM sodium propionate, or 15 mM sodium acetate resulted in ~6.99-, 6.46-, and 5.58-fold increases, respectively, in nargenicin $A_1$ production. Our overall results showed that among the supplements, methyl oleate was the most effective precursor supporting the highest titers of nargenicin $A_1$ in Nocardia sp. CS682, Nocardia sp. metK18, and Nocardia sp. ACC18.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.401-411
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• 1995

Flavobacterium spp., Pseudomonas spp., and Vibrio spp. were isolated from samples(sediments) of Sagami Bay and Suruga Bay(in Japan) at 810-4,000m in depth. Among isolated strains, Vibvio sp.-86 and sp.-87 strains were identified as barophilic and psychrophilic ones. They grew in 400 atm and showed best growth at 100 atm. Marine bacteria grown at 400 atm were long rod shape and 30 to 50times longer than those grown at 1 atm. which were short rod shape and formed flocks (aggregates). Vibrio sp,-86 strain grew at $5-37^{\circ}C\;and\;0,5-9.0\%\;NaCl\;(3.0\%\;of\;optimum\;concentration),$ while Vibrio sp.-87 strain grew at $1-7\%\;NaCl\;(2,0\%\;of\;optimum\;concentration).$ The fatty acid compositions of Vibrio sp.-86 strain grown at 1 atm were $C_{20}-C_{22:0},\;C_{l6:1},\;and\;C_{16:0}$ in the order of their abundance and at 400 atm the order were $C_{18:1},\;C_{18:0},\;and\;C_{20}-C_{22}$, whereas those of Vibrio sp.-87 strain at 1 atm were $C_{6:1},\;C_{14:1},\;and\;C_{20}-C_{22}$ and at 400 atm the order were $C_{14:1},\;C_{12:0},\;and\;C_{16:1}$ The amino acids compositon of Vibrio sp.-86 strain grown at 1 atm were abundant in the order of aspartic acid, methionine, and glutamic acid and those at 400 atm were abundant in the order of methionine, glutamic acid, and aspartic acid. The amino acids composition of Vibrio sp.-87 strain grwon at 1 atm were abundant in the order of methionine, glutamic acid, and aspartic acid and those at 400 atm were abundant in the order of methionine, glutamic acid, and isoleucine.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.451-458
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• 2002

Absorptive type SP3T(Single Pole Three Throw) and SP8T switch modules over the 6-18 GHz are designed and fabricated. The epitaxial structure of GaAs PIN diode for switch modules are designed for low loss and high power capability. The maximum input power of SP3T and SP8T switch modules are 2 W and 1 W, respectively. The switching time with driver circuit is less than 130 nsec. The maximum insertion loss of SP3T switch module and SP8T module shows 2.8 dB and 4.2 dB, respectively. The isolation between input port and output port is more than 55 dB. Two switch modules for electronic warfare system have passed the environment tests of the related test items.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.143-148
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• 1999

Two sibling species of the genus Platycephalus collected from the South and West Sea of Korea were reviewed based on the several meristic and morphological characters, electrophoresis of muscle protein, and LDH and MDH isozyme. Counts and morphometric characters of Platycephalus indicus were different from those of Platycephalus sp. by having 18~20 pectoral fin rays (16~19 in Platycephalus sp.), 70~80 scales of lateral line (83~100), 10.2~13.1% eye diameter (10.9~15.5%), 14.5~18.1% interorbital width (11.8~17.8%), dark brown of body color (light brown) and dark brown of pectoral and ventral fin outside (light brown and pale). The number of soluble protein bands in muscle separated by polyacrylamidegel electrophoresis was 16 and 18 from P. indicus and Platycephalus sp, respectively, and each bands showed their characteristics in activated degree. The number of bands separated from LDH isozyme were 2 and 1 in P. indicus and Platycephalus sp. and in the case of MDH isozyme, 5 and 4 bands, respectively. So we were thought that P. indicus and Platycephalus sp. from Korea were different species each other.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.86-103
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• 2003

Objective : Recently, many studies have showed the evidences of the effect of the acupunture treatment through scientific methods. One of these methods is functional MRI. We performed electro-acupunture on Sp6 and observed the changes of brain activation using fMRI. Methods : To see the effect of electro-acupunture stimulation on Sp6, the experiment was carried out on 12 healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right Sp6, 2Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. The Image analysis including motion correction, talairach transformation, and smoothing was done with SPM99. Results : 1. Group averaged brain activation induced by bilateral eletro-acupunture stimulation on Sp6 activates Brodman Area 3, 7, 13. 2. Group averaged brain deactivation induced by bilateral eletro-acupunture stimulation on Sp6 activates Brodman Area 6, 38, 47. 3. Group averaged brain activation induced by unilateral(right side) eletro-acupunture stimulation on Sp6 activates Brodman Area 5, 6, 13, 17, 18, 19, 31, 38, 40 ptoms, back pain(32.5%) was the 4. Group averaged brain deactivation induced by unilateral(right side) eletro-acupunture stimulation on Sp6 activates Brodman Area 3, 4, 18, 21, 36, 38, 39. 5. Brain region activated by motor stimulation activates Brodman Area 3, 4, 6, 18, 19.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.319-328
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• 1997

To develop a beneficial microbial feed for the cultivation of rotifer, Brachionus plicatilis, an aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ was isolated from marine structure at Haeundae beach in Pusan, Korea. Feeding effects of Erythrobacter sp. $S\;\pi-I$ on the growth of rotifer were analyzed comparing to other feeds such as PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. Erythrobacter sp. $S\;\pi-I$ contained more linoleic acid $(C_{18:3\omega3})$ and oleic acid $(C_{18:1\omega9})$ and amino acids than PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. The rotifer fed on Erythrobacter sp. $S\;\pi-I$ showed better effects than those fed on other feeds in the individual growth, size and weight. Also, the rotifer especially contained more eicosapentaenoic acid $(C_{20:5\omega3})$ and docosahexaenoic acid $(C_{22:6\omega3})$ in case of Erythrobacter sp. $S\;\pi-I$ feeding than the other feeds. In case of the feed of PSB and baker's yeast docosahexaenoic acid $(C_{22:6\omega3})$ did not show. In amino acid analysis, the rotifer fed on Erthrobacter sp, $S\;\pi-I$ showed more amino acid content comparing to those fed on other diets. Especially, arginine, isoleucine, histidine, lysine, methionine, phenylalanine, threonine, which are essential amino acid for fish growth, showed high contents. These results suggested that the aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ would be a beneficial microbial teed for the cultivation of rotifer.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.63-66
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• 2008

Anthracene is a PAH that is not readily degraded, plus its degradation mechanism is still not clear. Thus, two strains of anthracene-degrading bacteria were isolated from long-term petroleum-polluted soil and identified as Sphingomonas sp. 12A and Pseudomonas sp. 12B by a 16S rRNA sequence analysis. To further enhance the anthracene-degrading ability of the two strains, the biosurfactants produced by Pseudomonas aeruginosa $W_3$ were used, which were characterized as rhamnolipids. It was found that these rhamnolipids dramatically increased the solubility of anthracene, and a reverse-phase HPLC assay showed that the anthracene degradation percentage after 18 days with Pseudomonas sp. 12B was significantly enhanced from 34% to 52%. Interestingly, their effect on the degradation by Sphingomonas sp. 12A was much less, from 35% to 39%. Further study revealed that Sphingomonas sp. 12A also degraded the rhamnolipids, which may have hampered the effect of the rhamnolipids on the anthracene degradation.

• Journal of Life Science
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• v.22 no.2
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• pp.167-176
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• 2012

Three protease-producing halophilic bacteria were isolated from fermenting anchovy. Isolated FAM 10, FAM 114, and FAM 115 were found to grow optimally at salt concentrations of 2-4%, 10%, and 6%, respectively, and could grow in salinity of up to 18-22%. The salinity conditions for optimum protease production were 6% in FAM 10 and 10% in FAM 114 and FAM 115. The protease activity of FAM 10 was gradually inhibited by the addition of NaCl up to 10%, and was not evident at 14%, whereas FAM 114 and FAM 115 displayed protease activity at 14% NaCl and could not be measured at 18%. These results demonstrated that the three isolated strains belong to protease-producing, moderately halophilic bacteria. Strain FAM 10, FAM 114, and FAM 115 were identified as Salinivibrio sp., Halobacillus sp., and Halobacillus sp. respectively, based on comparative analyses of the 16S rRNA gene and the 16S-23S intergenic space sequence (IGS), biochemical testing, and Gram staining. Salinivibrio sp. FAM 10 had two 16S rDNAs containing different sequences at position 191 and four IGSs that harbored no tRNA gene and tRNA genes for isoleucine, alanine, glutamate, lysine, and/or valine. Halobacillus sp. FAM 114 and FAM 115 had completely identical 16S rRNA gene sequences and showed 99% identity to the sequences of various Halobacillus strains. The three IGSs found in the genome of both strains displayed 99% sequence identity with Halobacillus aidingensis and Halobacillus sp. JM-Hb, and had $IGS^0$ with no tRNA gene and $IGS^{IA}$ with tRNA genes for isoleucine and alanine.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.456-464
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• 1998

For the standardization and quality improvement of traditional Korean Nuruk, 10 strains of fungi, which were isolated from Nuruks and showed good productivity of the saccharogenic and dextrinogenic enzymes, acid and flavor, were selected and their enzymological characteristics and identification were carried out. Aspergillus spp. and Rhizopus sp. showed a high liquefying activity without regard to cultivation time, whereas the majority of strains except for Rhizopus sp. had decreasing saccharifying activity in proportion to the increase in cultivation time. Aspergillus spp. No.17-2, No.17-6 and Rhizopus sp. No.18-1 showed high liquefying and saccharifying activity after 15 and 30 day cultivation. The optimum temperature of most of these saccharogenic and dextrinogenic enzymes was from 40$^{\circ}C$ to 60$^{\circ}C$, and their optimum pH was extensive between pH 3 and pH 11. But Penicillium spp.(2 strains) and Rhizopus sp. showed low activity under the alkalic and acidic conditions. Among these isolated strains, 5 strains which had shown the high productivity of materials were identified as Aspergillus oryzae NR3-6 and Aspergillus oryzae NR17-6, Aspergillus penicilloides NR12-1, Penicillium expansum NR7-7 and Rhizopus oryzee NRl8-1, respectively. Five kinds of mixed culture were carried out and all of them showed a better productivity of saccharogenic and dextrinogenic enzymes than single culture. These results indicate that it is possible to make traditional Korean liquors of good quality by using these fungi.

• Journal of the Korean Institute of Gas
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• v.18 no.1
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• pp.61-67
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• 2014

Small punch(SP) tests were performed on high strength Dual Phase(DP) steels in order to evaluate the behavior of hydrogen embrittlement. For this purpose, three different kinds of DP steel specimens were charged with hydrogen by electochemical hydrogen charging experiment. After charging with hydrogen, the amount of charged hydrogen was measured. The measurement results showed that amounts of charged hydrogen were largely dependent on the martensite volume fraction of DP steel. The hydrogen charging time of 25 hrs with current densities of 150 and $200mA/cm^2$ was investigated as saturation condition with hydrogen. The analysis results on the SP energy and height of SP bulbs after SP tests showed that those were decreased as the amount of charged hydrogen increased. Fractographs of SP bulbs were observed a brittle fracture mixed with quasi-cleavage fractures, layered structures and clear facets.