• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.156-162
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• 2016

In this study, we isolated a new agar-degrading marine bacterium and characterized its agarase. An agardegrading marine bacterium SH-1 was isolated from seawater, collected from the seashore of Namhae in Gyeongnam province, Korea, and cultured in marine agar 2216 media. It was identified as Maribacter. sp. SH-1 by phylogenetic analyses, based on 16S rRNA gene sequence. The extracellular agarase was extracted from culture media of Maribacter sp. SH-1 and characterized. Its relative activities were 56, 62, 94, 100, and 8% at 20, 30, 40, 50, and 60℃, respectively, whereas 15, 100, 60, and 21% relative activities were observed at pH 5, 6, 7, and 8, respectively. Its extracellular agarase exhibited maximum activity (231 units/l) at pH 6.0 and 50℃, in 20 mM Tris-HCl buffer. Therefore, this agarase would be applicable as it showed the maximum activity at the temperature at which the agar is in a sol state. Furthermore, the agarase activities remained over 90% at 20, 30, and 40℃ after 0.5 h exposure at these temperatures. Thin layer chromatography analysis suggested that Maribacter sp. SH-1 produces extracellular β-agarase, as it hydrolyzes agarose to produce neoagarooligosaccharides, such as neoagarohexaose (34.8%), neoagarotetraose (52.2%), and neoagarobiose (13.0%). Maribacter sp. SH-1 and its β-agarase would be useful for the production of neoagarooligosaccharides, which shows functional properties, like skin moisturizing, skin whitening, inhibition of bacterial growth, and delay in starch degradation.

• Journal of Life Science
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• v.28 no.8
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• pp.938-944
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• 2018

This study evaluated tyrosinase, elastase inhibitory, and antioxidant activities of fermented Rhododendron micranthum Turcz. extract using a lactic acid bacterium, Lactobacillus rhamnosus. The optimum conditions for fermentation of R. micranthum Turcz. extract were $37^{\circ}C$ and 3% R. micranthum Turcz. extract for 3 days based on the bacterial cell number, total phenolic compounds, DPPH radical scavenging activity, and tyrosinase and elastase inhibitory activity. After culture for 3 days using 3% R. micranthum Turcz. extract, the cell mass of L. rhamnosus reached $5.7{\times}10^9CFU/ml$. The results indicated that R. micranthum Turcz. extract can be used for industrial lactic acid bacteria culture. After fermentation under optimum conditions, the total content of phenolic compounds of the fermented R. micranthum Turcz. extract was 157 GAE mg/ml, and the $IC_{50s}$ of DPPH radical scavenging activity, ABTS radical scavenging activity, and tyrosinase and elastase inhibitory effects were 78.8, 79.8, 329.1, and $449.5{\mu}g/ml$, respectively. The fermented R. micranthum Turcz. extract exhibited 1.2-, 1.3-, 1.5-, 2.4-, and 5.6-fold higher total content of phenolic compounds, DPPH radical scavenging activity, ABTS radical scavenging activity, and tyrosinase and elastase inhibitory effects than the nonfermented R. micranthum Turcz. extract. These results indicated that fermented R. micranthum Turcz. extract using L. rhamnosus can be used for developing new natural functional ingredients for the health food or cosmetic industry.

• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.362-368
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• 2006

SH group modifying chemicals were used to characterize the eight cysteine residues of cabbage PLD. 5,5-dithiobis(2-nitrobenzoate)(DTNB) was used to titrate the SH group of cysteine residues . Based on the optical density at 412nm due to the reduced DTNB, 4 SH groups are found to be present in a native PLD while 8 SH groups in the denatured PLD whose tertiary structure was perturbed by 8M urea. The results imply that among the 8 cysteine residues of PLD, the half(4) are exposed on the surface whereas the other half are present at the interior of the enzyme tertiary structure. The PLD was inactivated by SH modifying reagents such as p-chloromercuribenzoate(PCMB), iodoacetate, iodoacetamide, and N-ethylmaleimide. At the addition of dithiothreitol(DTT) only the PCMB inhibited PLD activity was recovered reversibly. The micro-environment of the exposed SH group of cysteine residues was examined with various disulfide compounds with different functional groups and we found that anionic or neutral disulfides appear to be more effective than the positively charged cystamine for inactivating the PLD activity. The effect of redox state of cysteine residues on the PLD activity was further explored with H2O2. The oxidation of SH groups by H2O2 inhibited the PLD activity more than 70%, which was mostly recovered by DTT. From these results, we could confirm chemically that all the cysteine residues of PLD are present as in their reduced SH forms and the 4 SH groups exposed on the surface of the enzyme may play important roles in the regulation of PLD activity.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.145-152
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• 1990

We recently reported a development of an experimental system which can identify the release of a superoxide-dependent vasorelaxant factor from endothelial cells using a two-bath system. In the present work, we further exploited the above system and observed whether the superoxide-dependent relaxing factor(s), released from the porcine coronary artery (PCA) endothelium, was similar in relaxation to those obtained from cat thoracic aortic endothelium and cultured endothelial cells of bovine aorta. However, there was observed a novel difference among the former one and the latter two relaxing factors; the release of relaxing factor from PCA endothelium can be inhibited either by catalase or by superoxide dismutase (SOD), whereas the latter two can be inhibited only by SOD. It was further attempted to characterize the synthetic mechanisms of the relaxing factors: (1) They were readily inhibited by various lipoxygenase inhibitors (gossypol, nordihydroguaiaretic acid, AA 861, and eicosatetraynoic acid). (2) They were not inhibited by cyclooxygenase inhibitor (indomethacin) and by cytochrome P-450 monooxygenease inhibitors (proadifen and cimetidine). Thus, it is likely that these relaxing factors, although obtained from different species, show common functional roles of arteriolar relaxation. It is suggested that they are related to pathophysiological involvement of various tissue ischemia-reperfusion injuries.

• Genomics & Informatics
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• v.10 no.2
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• pp.99-105
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• 2012

Dyslipidemia, mainly characterized by high triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C) levels, is an important etiological factor in the development of cardiovascular disease (CVD). Considering the relationship between childhood obesity and CVD risk, it would be worthwhile to evaluate whether previously identified lipid-related variants in adult subjects are associated with lipid variations in a childhood obesity study (n = 482). In an association analysis for 16 genome-wide association study (GWAS)-based candidate loci, we confirmed significant associations of a genetic predisposition to lipoprotein concentrations in a childhood obesity study. Having two loci (rs10503669 at LPL and rs16940212 at LIPC) that showed the strongest association with blood levels of TG and HDL-C, we calculated a genetic risk score (GRS), representing the sum of the risk alleles. It has been observed that increasing GRS is significantly associated with decreased HDL-C (effect size, $-1.13{\pm}0.07$) compared to single nucleotide polymorphism combinations without two risk variants. In addition, a positive correlation was observed between allelic dosage score and risk allele (rs10503669 at LPL) on high TG levels (effect size, $10.89{\pm}0.84$). These two loci yielded consistent associations in our previous meta-analysis. Taken together, our findings demonstrate that the genetic architecture of circulating lipid levels (TG and HDL-C) overlap to a large extent in childhood as well as in adulthood. Post-GWAS functional characterization of these variants is further required to elucidate their pathophysiological roles and biological mechanisms.

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.165-172
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• 2003

Humic acids present in the soils at the vicinity of domestic atomic power plants(NPPs), located in Yeongkwang(YK), Uljin(UJ), Kori(KR), Koseong(KS), Wolseong(WS) area were isolated, and characterized using elemental analysis and UV/Vis, IR, CPMAS $^{13}C$ NMR spectroscopic methods. The characteristics were compared with one another and with commercial humic acid (Aldrich Co.). Molecular size distributions of the humic acids were determined using a stirred cell ultrafiltration technique. The results of elemental analysis showed that soil humic acid from UJ contains higher oxygen content than humic acids from KR and KS (O/C ratios: 0.51 (UJHA) us. 0.45(KRHA), 0.43(KSHA)). The molecular size distribution revealed that the soil humic acids of UJ and YK contained a higher percentage of larger molecules of > 30,000 daltons, compared to those of KR and KS. The spectral features obtained from UV/vis., IR and CPMAS $^{13}C$ NMR showed that the aromatic character and oxygen containing functional groups in the humic acids from UJ and YK were relatively higher than those of KR and KS. These results indicate that the soil humic acids from UJ and YK were in a higher degree of humification, which may suggest higher affinity of the humic acids with radionuclides released in the soil environments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.179-184
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• 2006

This study was carried out to evaluate major agronomical characterization and phenol compound contents, Xanthine oxidase inhibitory activity (XO), Catalase activity, Superoxide dismutase activity (SOD) and 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical sacvenging activity were analyzed in colored waxy corns. The mean of stem height and ear length were 248.8 cm and 18.6 cm, respectively. The pericarp thickness in CNU108 $(30.3{\mu}m)$ was thinner than other hybrids. The period of tasseling days in CNU69 and CNU202 were very shorter than other hybrids (59 days). 100-kernel weight of CNU50 was 35.6 g and heavier than the others. The antioxidant activities such as xanthin oxidase (XO), catalase and superoxide dismutase (SOD) were higher in CNU70 and CNUI 38. Especially highest EDA (electron donating ability) in DPPH radical scavenging effect was 94.8% and 94.6% in CNU160 and CNU193, respectively. In the results, the antioxidant enzyme activity and antioxidant acticity were higher in CNU109 and CNU 34 hybrids. The hybrids, CNU34, CNU70, CNU108, CNU 138 and CNU193 may be considered higher functional color waxy corn.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.297-302
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• 1998

$\beta$-Xylosidase B was produced by Escherichia coli HB101/pKMG12 carrying the xylB gene of Bacillus stearothermophilus No.236 on its recombinant plasmid. The $\beta$-xylosidase B produced was purified by ammonium sulfate fractionation, DEAE-Sepharose CL-6B, Sephacryl S-200 and Superdex 200 HR gel filtration. The purified enzyme showed the highest activity at pH 6.5 and 5$0^{\circ}C$. But, the enzyme was observed to be very sensitive to the pH and temperature of the reaction mixture. The enzyme was activated about 35% of its original activity in the presence of 1 mM of $Mn^{2+}$ but it was completely inhibited by $Ag^{+}$, $Cu^{2+}$and $Hg^{2+}$ions. In contrast with the $\beta$-xylosidase A, the B enzyme was found to have $\alpha$-arabinofuranosidase activity though the activity was fairly low compared with the $\alpha$-arabinofuranosidase produced from the arfI gene of the same Bacillus stearothermophilus. Therefore, $\beta$-xylosidase B is considered to be more suitable than $\beta$-xylosidase A at least for the biodegradation of arabinoxylan. The $K_{m}$ and V$_{max}$ values of the $\beta$-xylosidase B for o-nitrophenyl-$\alpha$-D-xylopyranoside were 6.43 mM and 1.45 $\mu$mole/min, respectively. Molecular mass of the enzyme was determind to be about 54 kDa by SDS-PAGE and 160 kDa by Superdex 200HR gel filtration, indicating that the functional $\beta$-xylosidase B was composed of three identical subunits.s.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.46-53
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• 2001

A commensal thermophile, Symbiobacterium toebii, isolated from hay compost (toebii) in Korea commensally interacted with a thermophilic Geobacillus toebii sp. nov., which was a new species within the genus Geobacillus on the basis of the phenotypic traits and molecular systematic data. S. toebii required the crude extracts and/or culture supernatant of the Geobacillus toebii for axenic growth and could grow on the temperature between 45 and $70^{\circ}C$ (optimum: $60^{\circ}C$; 2.4 h doubling time) and pH 6.0 and 9.0 (optimum: pH 7.5). The G+C content of the genomic DNA was $65 mol\%$, and the major quinones were MK-6 and MK-7. A phylogenetic analysis of its 16S rDNA sequence indicated that Symbiobacterium toebii was closely related with solely reported Symbiobacterium thermophilum. The presence of the commensal thermophile 16S rDNA and accumulation of indole in all the enriched cultures indicate that Symbiobacterium toebii is widely distributed in the various soils. The genome of S. toebii constituted a circular chromosome of 3,280,275 base pairs and there was not an extra-chromosomal element (ECE). It contained about 4,107 predicted coding sequences. Of these protein coding genes, about $45.6\%$ was encoded well-known proteins and annotated the functional assignment of 1,874 open reading frames (ORFs), and the rest predicted to have unknown functions. The genes encoding thermostable tyrosine phenol-lyase and tryptophan indole-lyase were cloned from the genomic DNA of S. toebii and the enzymatic production of L-tyrosine and L-tryptophan was carried out with two thermostable enzymes overexpressed in recombinant E. coli.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.526-530
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• 2010

Isopentenyl diphosphate(IPP) isomerization to dimethylallyl diphosphate(DMAPP) is an important step for the efficient production of isoprenoids such as lycopene, ${\beta}$-carotene, astaxanthin, etc. The type II isopentenyl diphosphate isomerase gene from Synechocystis sp. PCC6803(sll1556, Syidi2) was cloned and expressed in Escherichia coli $DH5{\alpha}$. When E. coli $DH5{\alpha}$ harboring lycopene synthesis genes, crtE, crtB, and crtI and mevalonate pathway genes, MvK1, MvK2, and Mvd, was cultured on LB medium containing mevalonate, the strain grew very slowly be due to the toxicity of isopentenyl diphosphate derived from mevalonate. When Syidi2 was introduced to E. coli $DH5{\alpha}$ harboring the lycopene synthesis genes and mevalonate pathway genes, growth on mevalonate medium was fully restored and the colony showed red color indicating lycopene formation. The growth rate of the mutant strain, E. coli $DH5{\alpha}$(idi::${\Delta}km$), was very slow because of IPP accumulation and DMAPP deprivation. Ultimately the idi mutant was complemented by introducing the Syidi2 gene.