• Korean Journal of Microbiology
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• v.49 no.1
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• pp.8-16
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• 2013

A GAL4 type transcription factor gene (formally annotated as AN3912) locating downstream of sndA (AN3911) was characterized. The putative transcription factor carries both Zn(II)2Cys6 binuclear cluster DNA-binding domain and transcription activator domain. The gene named gtfA (gal4 type transcription factor) had an open reading frame which consisted of 762 amino acids and was disrupted by three introns. The deletion mutant produced reduced amount of conidia but increased amount of fruiting bodies, suggesting that the GtfA make function in decision of asexual preferential to sexual development. The forced over expression of gtfA caused the retardation of fruiting body formation on high glucose concentration. The transcript level of gtfA was kept constant through the life cycle except late vegetative stage and early sexual development stage during which slight increase was found. The expression of gtfA was not significantly affected by sexual or asexual development regulators, such as VeA, NsdD or FluG, FadA, and SfaD. The GtfA repressed the nsdC transcription, which suggested that GftA control sexual development negatively via negative regulation of nsdC expression.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.435-447
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• 2016

Anthropogenic emissions of $PM_{2.5}$ in Chuncheon are considered to be low according to the national emissions inventory; however, the atmospheric $PM_{2.5}$ concentrations have been reported to be higher than or at least similar to those measured in metropolitan (e.g. Seoul) and/or in industrial cities (e.g. Incheon, Ulsan). In this study, the concentrations of $PM_{2.5}$ and its ionic and carbonaceous compounds were measured from Jan. 2013 to Dec. 2014 in Chuncheon, Korea to identify the characteristics of high $PM_{2.5}$ concentration event. Average $PM_{2.5}$ concentration was $34.6{\mu}g/m^3$, exceeding the annual air quality standard ($25{\mu}g/m^3$). The most abundant compound was organic carbon (OC), comprising 26% of $PM_{2.5}$ mass, followed by $SO_4{^{2-}}$. Among 14 high concentration events, three events showed clearly enhanced contributions of OC, $SO_4{^{2-}}$, $NO_3{^-}$ and $NH_4{^+}$ to $PM_{2.5}$ under the fog events. One event observed in summer showed high concentration of $SO_4{^{2-}}$ while the high wind speeds and the low $PM_{2.5}/PM_{10}$ ratios were observed for the two high concentration events. These results indicate that the secondary aerosol formation under the fog events and high atmospheric temperature as well as the regional and/or the long-range transport were important on enhancing $PM_{2.5}$ concentration in Chuncheon. Cluster analysis based on back trajectories also suggested the significant impacts of regional transport from China and metropolitan areas of Korea on $PM_{2.5}$ in Chuncheon.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.134-137
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• 1999

The polyacenic semiconductor material (PAS) electrode prepared by the pyrolytic treatment of phenol-formaldehyde resin is one of useful electrodes. As an anode material of lithium rechargeable batteries, amorphous carbon materials have been studied extensively because of their high electrochemcal performance and cyclicability. Carbon materials do not lead to the formation of lithium dendrite which is one of the most serious problems in applying Li-based materials to an electrode of batteries. The polyacene materials prepared from phenol resin at relatively low temperatures $(550\~750^{\circ}C)$ show a highly Li\doped state up to $C_2Li$ state without liberation of Li cluster. We prepared each polyacene materials at various temperature and investigated electro- chemical properties. We tried to change the mole ratio of [H]/[C] which is $0.24\~0.4$ range. Considering of electrochemical properties of PAS material, the PAS material is one of the most suitable materials for electrodes of a polymer battery.

• Journal of Life Science
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• v.14 no.5
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• pp.752-760
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• 2004

The function of the [4Fe-4S] cluster containing iron (Fe-) protein in nitrogenase catalysis is to serve as the nucleotide-dependent electron donor to the MoFe protein which contains the sites for substrate binding and reduction. The ability of the Fe protein to function in this manner is dependent on its ability to adopt the appropriate conformation for productive interaction with the MoFe protein and on its ability to change redox potentials to provide the driving force required for electron transfer. The MgADP-bound (or off) conformational state of the nitrogenase Fe protein structure described reveals mechanisms for long-range communication from the nucleotide-binding sites to control affinity of association with the MoFe protein component. Two pathways, termed switches I and II, appear to be integral to this nucleotide signal transduction mechanism. In addition, the structure of the MgADP bound Fe protein provides the basis for the changes in the biophysical properties of the [4Fe-4S] observed when Fe protein binds nucleotides. The structures of the nitrogenase Fe protein with defined amino acid substitutions in the nucleotide dependent signal transduction pathways of the Switch I and Switch II have been determined by X-ray diffraction methods. These two pathways have been also implicated by site directed mutagenesis studies, structural analysis and analogies to other proteins that utilize similar nucleotide dependent signal transduction pathways. We have examined the validity of the assignment of these pathways in linking the signals generated by MgATP binding and hydrolysis to macromolecular complex formation and intermolecular electron transfer. The results provide a structural basis for the observed biophysical and biochemical properties of the Fe protein variants and interactions within the nitrogenase Fe protein-MoFe protein complex.

• Journal of Life Science
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• v.21 no.3
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• pp.341-348
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• 2011

In an effort to gain greater understanding of the maternal lineages of the Jeju native pig (JNP), we analyzed the mitochondrial DNA (mtDNA) CYTB gene and compared it with those of other pig breeds. PCR-RFLP analysis was conducted with six pig breeds including JNP, and then the RFLP patterns allowed for the separation of the pig breeds into two distinct haplotypes (mtCYTB1 and mtCYTB2). The JNP CYTB sequences were detected in both the European and Asian breed clusters on the phylogenetic tree. The J2 group was sorted with the indigenous cluster of Asian pig lineages and was related closely to Chinese native pig breeds, but a second group, J1, was sorted with the European pig lineages and appeared to be related to Spanish Iberian native pigs, rather than to Asian breeds. These results indicate that the JNP currently raised on Jeju Island have two major maternal origins estimated in Asian and European pigs. We concluded that the JNP that share a common lineage with indigenous Asian pigs were domesticated in the distant past, originating from pigs that were already being raised elsewhere at that time, and that the European pig breeds introduced in the twentieth century have also contributed to the formation of this pig population.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1319-1325
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• 2000

Antimicrobial effects of the specific IgY separated from eggs which were laid by hens vaccinated with Streptococcus mutans were investigated. The comparison tests of vaccination, addition levels of crude specific IgY, and innoculation concentration were applied by microscopic observation and turbidity test. Ten% addition of crude specific IgY obtained from vaccinated hens showed agglomerative clusters of S. mutans cells in supernatants and sediments, while crude IgY produced by non-vaccinated hens showed no cluster. IgY addition above 5% showed agglutinating clusters of most S. mutans cells and there was definite difference between IgY addition below 2.5% and above 5%. Concentration tests of crude IgY revealed that antimicrobial effects were differentiated by addition level and addition over 10% produced satisfactory results with turbidity test. The cluster size was dependent upon concentration of crude IgY addition. $10^5\;cfu/mL$ inoculation showed agglutinated cells and extent of agglomeration was proportional to cell numbers. Study of inoculation levels showed that 10% addition of crude IgY decreased turbidity effectively regardless of number of S. mutans cells. Plaque formation decreased to 75% with 15% addition of specific IgY concentration. These results implied that IgY separated from eggs laid by S. mutans-vaccinated hens might prevent dental caries caused by S. mutans.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.484-491
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• 2023

Maize is one of the major crops consumed in worldwide, which nutrients accounts for a large amount of starch, but also functional components, and phenolic acid is known to have a high content. Maize is divided into waxy maize, sweet maize, and normal maize with its shape and use, therefore there is also a difference in nutritional composition. This study was conducted to analyze the content of functional components according to the type of maize and to produce natural variation data in consideration of environmental factors. 3 shapes of maize (waxy maize, sweet maize, and normal maize) samples cultivated in 3 regions (Suwon, Daegu, and Hongcheon) were analyzed using HPLC and GC-TOF-MS. Comparing with type through ANOVA, multivariate statistical analysis, Pearson correlation analysis, 28 components, including carotenoids and tocopherols, showed significant differences among a total of 32 components (p <0.05), 15 of them showed very significant differences (p <0.001). When comparing with regions, 15 components showed significant differences and only vanillate, syringate, C23-ol of them showed most significant differences (p <0.001). As a result of principal component analysis, cluster classification was distinguished by shape than by region, with α-carotene, cholesterol for waxy maize, vanillate and stigmasterol for sweet maize, lutein and β-carotene for normal maize had a great effect on cluster formation. It suggests that the content of functional components is more affected by genetic factors than environmental factors.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.184-190
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• 2013

Cave environment provides special ecosystems for evolution of lives distant from surface environments. We investigated bacterial and archaeal communities of wall biofilm obtained from of a volcanic cave (Daesubee) in Jeju, Republic of Korea. Bacterial and archaeal 16S rRNA genes were PCR-amplified and sequenced using pyrosequencing technologies. Unique prokaryotic communities with low diversities were observed. The main bacterial sequences (ca. 83% of total reads) were affiliated with Pseudonocardia mongoliensis of phylum Actinobacteria and clustered with clones obtained from various caves. Reflection of light on the wall surface of cave might be caused by formation of beads of water caused by hydrophobic filaments of actinobacterial colonies. Main archaeal sequences (ca. 65.7% of total reads) were related with those of I.1a-Associated group of phylum Thaumarchaeota. The sequences were related with that of Candidatus Nitrosotalea devanaterra which was known to oxidize ammonia under acidic condition (ca. pH 5.0). Nutrients leached through volcanic soils contribute formation of unique microbial communities of wall biofilm of cave Daesubee.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.82.2-82.2
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• 2013

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is being developed by KASI. The NISS will perform the imaging low-resolution spectroscopic observation in the near-infrared range for nearby galaxies, low background regions, starforming regions and so on. The off-axis reflecting telescope with a wide field of view (2 deg. ${\times}$ 2 deg.) will be operated in the wavelength range from 0.95 to $3.8{\mu}m$. In order to reduce thermal noise, a telescope and a HgCdTe infrared sensor will be cooled down to 200K and 80K, respectively. To evade a stray light outside a field of view and use limited space efficiently, the NISS adopted the off-axis reflective optical system. The primary and secondary mirrors, optomechanical part and mechanical structure were designed to use the same material. It will lessen the degradation of optical performance due to a thermal variation. The purpose of NISS is the observation of cosmic near-infrared background in the wide wavelength range as well as the detection of near-infrared spectral lines in nearby galaxies, cluster of galaxies and star forming regions. It will give us less biased information on the star formation history. In addition, we will demonstrate the space technologies related to the development of the Korea's leading near-infrared instrument for the future large infrared telescope, SPICA.

• Journal of the Korean Chemical Society
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• v.45 no.2
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• pp.116-120
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• 2001

In order to know the physicochemical properties of magnetized water, the experimental methods of column assay, crystalization of saltsand gypsom have been explored to elucidate the effects of magnetized water on the solubility speed of salts, crystal pattern from salt squeous solutions, and gypsom crystal pattern, respectively. In the column assay for salt solubility the magnetized water showed the decreased initial solubility speed of NaCl and slightly increased initial solubility spped of KCI, however, the maximum solugilities of NaCl and KCI in the magnetized aster were almost same in the double distilled water, respectively. The column assay also indicated that the magnetized water showed the decreased initial solubility speed of urea (CH$_4$N$_2$O), sodium citrate (HOC(CO$_2$Na)-(CH$_2$CO$_2$Na)$_2$-2H$_2$O) and (NH$_4$)$_2$compared to the double distilled water, while slightly increased solubility speed of glycine (NH$_2$CH$_2$COOH), boric acid (H$_3$BO$_3$), MgSO$_4$. Crystalization of 1% or 5% salt aqueous solutions by rapid evaporation disclosed that the magnetized water produced more condensed and bigger crystal structure than the control water. The pattern of gypsom crystal formation also indicated that the magntized water enhanced the crystal formation in the hydration reaction of gypsom plaster compared to the double distilled water. Taken together, it was presumed that the magnetized water showed the different physicochemical properties in the interaction with various salts, especially showed the contrast results between NaCl and KCI.