• Macromolecular Research
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• v.17 no.2
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• pp.84-90
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• 2009

We prepared side-chain liquid crystalline polymers comprising two monomeric units, one having a mesogenic side group that could form a smectic mesophase and the other having a phenolic group attached to the polymer backbone via a thermally reversible urethane bond. The urethane linkage between the isocyanate and phenol groups was stable at room temperature, but it cleaved to generate an isocyanate group when the temperature was increased. When annealed, the copolymers in their smectic mesophases became insoluble in common organic solvents, suggesting the formation of network structures. XRD analysis showed that the annealed polymers maintained their smectic LC structures. The crosslinking process probably proceeded via the reaction of the dissociated isocyanate groups. Some of the isocyanate groups would have first reacted with moisture in the atmosphere to yield amino groups, which underwent further reaction with other isocyanate groups, resulting in the formation of urea bonds. We presume that only polymer chains in the same layer were crosslinked by the reaction of the isocyanate groups, resulting in the formation of a layered polymer network structure. Reactions between the layers did not occur because of the wide layer spacing.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1653-1663
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• 2010

The first gene (${\alpha}$-gal1) encoding an extracellular ${\alpha}$-Dgalactosidase from the thermophilic fungus Talaromyces emersonii was cloned and characterized. The ${\alpha}$-gal1 gene consisted of an open reading frame of 1,792 base pairs interrupted by six introns that encoded a mature protein of 452 amino acids, including a 24 amino acid secretory signal sequence. The translated protein had highest identity with other fungal ${\alpha}$-galactosidases belonging to glycosyl hydrolase family 27. The ${\alpha}$-gal1 gene was overexpressed as a secretory protein with an N-terminal histidine tag in the methylotrophic yeast Pichia pastoris. Recombinant ${\alpha}$-Gal1 was secreted into the culture medium as a monomeric glycoprotein with a maximal yield of 10.75 mg/l and purified to homogeneity using Hisbinding nickel-agarose affinity chromatography. The purified enzyme was maximally active at $70^{\circ}C$, pH 4.5, and lost no activity over 10 days at $50^{\circ}C$. ${\alpha}$-Gal1 followed Michaelis-Menten kinetics ($V_{max}\;of\;240.3{\mu}M/min/mg,\;K_m\;of\;0.294 mM$) and was inhibited competitively by galactose ($K_m{^{obs}}$ of 0.57 mM, $K_i$ of 2.77 mM). The recombinant T. emersonii ${\alpha}$-galactosidase displayed broad substrate preference, being active on both oligo- and polymeric substrates, yet had strict specificity for the ${\alpha}$-galactosidic linkage. Owing to its substrate preference and noteworthy stability, ${\alpha}$-Gal1 is of particular interest for possible biotechnological applications involving the processing of plant materials.

• Journal of Korean Society of Forest Science
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• v.78 no.3
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• pp.255-262
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• 1989

Vegetation data of the mixed mesophytic forest in Mt. Chombong area were analyzed by the methods of classification and ordination. 'Weighted group average linkage cluster analysis' recognized five distinctive vegetation groups, based on the abundance data of 83 woody plant species in 70 sampling units. The species diversity was also examined for each group. The importance values of 42 tree species in the groups were subjected to principal component analysis (PCA). The PCA ordinated five vegetation groups on the first two axes, so as to compare similarity among them in terms of species composition. Acer palmatum, Fraxinus rhynchophylla, Quercus mongolica, and Acer mono had greatest influence on the determination of group scores with high eigenvectors (component loadings) in the first axis. Distribution of these four dominant species appeared to be important in determining community association in this diversified forest.

• Korean Journal of Microbiology
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• v.20 no.2
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• pp.53-66
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• 1982

1. When Chong Ju and Chung Ju soils possessing different physicochemical properties were treated with 500 ppm of TOK and incubated in flooded anaerobic condition for 2, 4, and 6 months, respectively, they produced 4-Chloro-4'-amino diphenyl ether, 2,4-Dichloro-4'-amino diphenyl ether(amin-TOK), N-[4'-(4-Chlorophenoxy)] phenyl acetamide, and N-[4'-(4-Chlorophenoxy)] phenyl formamide as the metabolities. This result indicates that TOK undergose the reduction of its $NO_2\;to\;NH_2$ group, dechlorination, acetylation, and formylation under this condition. The cleavage of ether linkage does not occur. In addition, TOK degrades more readily in Chung Ju soil which is characterized by pH 6.43 and higher contents of $Ca^{++}$ and C.E.C. than in Chong Ju soil which is lower in pH, $Ca^{++}$, and C.E.C. 2. In the aerobic incubation of TOK of 25ppm in Chung Ju soil suspension for 21 days, the ratio of the resulting metabolites, TOK : amino-TOK : 4-Chloro-4'-amino diphenyl ether was 100 : 130 : 76. Meanwhile, in the 42 day incubation, the ratio was 100 : 19 : 5, which indicates that TOK in aerobic condition dose not necessrily degrade as a function of the incubation period. 3. The citrate buffer extract of Chung Ju soil has the capability of degrading TOK, which was verified to be due to the action of the microorganisms involved. 4. Twelye strains of soil bacteria were isolated from the TOK-treated soils. In the incubation of TOK in pure cultures of the respective isolates, the strain T-1-1 isolated from Chong Ju soil had almost no degradability whereas the strain T-2-3 was the most potent. The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group. 5. In a test for the degradability of TOK by some selected microorganisms, Pseudomonas species were more potent than fungi. Yet, Isolate B which had been isolated from Chung Ju soil suspension was the most potent.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.357-363
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• 2022

South Korea faces elderly care crisis with both low fertility rate and rapid ageing rate. Long-term care insurance in 2008 has taken care burden from family to nation. However, few options, lack of tailored services, and unstable community care plan caused blankness of care in some areas. Especially, increasing dementia rate has become an emergent social issue. Welfare technology could be a useful alternative to fill out the gap between demand and supply. Using FGI method on two groups(high-risk dementia group and MCI group), intimacy, accessibility and preventive way of dementia with welfare technology are analysed in this paper. Despites of a few differences of dementia progress, interests towards technology are expressed. More suggestions using TV and normal telephone to improve daily independence are presented as well. Amongst MCI group, help-service for technology-use at ADS and linkage ways of in-home services are also suggested.

• Genomics & Informatics
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• v.6 no.1
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• pp.18-28
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• 2008

Single nucleotide polymorphisms (SNPs) are the most abundant forms of human genetic variations and resources for mapping complex genetic traits and disease association studies. We have constructed a linkage disequilibrium (LD) map of chromosome 22 in Korean samples and compared it with those of other populations, including Yorubans in Ibadan, Nigeria (YRI), Centre d'Etude du Polymorphisme Humain (CEPH) reference families (CEU), Japanese in Tokyo (JPT) and Han Chinese in Beijing (CHB) in the HapMap database. We genotyped 4681 of 111,448 publicly available SNPs in 90 unrelated Koreans. Among genotyped SNPs, 4167 were polymorphic. Three hundred and five LD blocks were constructed to make up 18.6% (6.4 of 34.5 Mb) of chromosome 22 with 757 tagSNPs and 815 haplotypes (frequency $\geq$ 5.0%). Of 3430 common SNPs genotyped in all five populations, 514 were monomorphic in Koreans. The CHB + JPT samples have more than a 72% overlap with the monomorphic SNPs in Koreans, while the CEU + YRI samples have less than a 38% overlap. The patterns of hot spots and LD blocks were dispersed throughout chromosome 22, with some common blocks among populations, highly concordant between the three Asian samples. Analysis of the distribution of chimpanzee-derived allele frequency (DAF), a measure of genetic differentiation, Fst levels, and allele frequency difference (AFD) among Koreans and the HapMap samples showed a strong correlation between the Asians, while the CEU and YRI samples showed a very weak correlation with Korean samples. Relative distance as a quantitative measurement based upon DAF, Fst, and AFD indicated that all three Asian samples are very proximate, while CEU and YRI are significantly remote from the Asian samples. Comparative genome-wide LD studies provide useful information on the association studies of complex diseases.

• Animal Bioscience
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• v.35 no.7
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• pp.999-1009
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• 2022

Objective: To improve the feeding value of rice straw (RS), this study evaluated the potential of rice straw fermented with Pleurotus sajor-caju (FRS) as dairy goat feed. Methods: Spent Pleurotus sajor-caju mushroom substrate was used as fungi inoculum to break the lignocellulose linkage of rice straw, which was solid-fermented at 25℃ to 30℃ for 8 weeks. The ruminal degradation of pangolagrass hay (PG), FRS, and RS were measured in situ for 96 hours in three dry Holstein cows, respectively. Effect of fungi fermented RS on milking performance was studied in feeding trials. A total of 21 Alpine goats a trial were divided into 3 groups: a control group in which PG accounted for 15% of the diet dry matter, and FRS or RS was used to replace the PG in the control group. Goats were fed twice a day under two 28-day trial in individual pens. Meanwhile, a 3×3 Latin square trial (14 days/period) was conducted to study the rumen digestion of three diets by using three fistulated dry goats. Rumen contents were collected for metabolite analyses every one to three hours on the last two days. Results: In situ study showed that fermentation could elevate the rumen degradable fraction and effective degradability of RS (p<0.05). Effective degradability of FRS dry matter was significantly increased from 29.5% of RS to 41.7%. Lactating trial results showed that dry matter intake and milk yield in the PG group and FRS group were similar and higher than those in RS group (p<0.05). The concentration of propionic acid and total volatile fatty acid in the RS group tended to be lower than those in PG group (p<0.10). There were no differences in rumen pH value and ammonia nitrogen level among the groups tested. Conclusion: Fermentation of rice straw by spent Pleurotus sajor-caju mushroom substrate could substantially enhance its feeding value to be equivalent to PG as an effective fiber source for dairy goat. The fermented rice straw is recommended to account for 15% in diet dry matter.

• BMB Reports
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• v.38 no.1
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• pp.77-81
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• 2005

The monocyte chemotactic protein-3 (MCP3), on chromosome 17q11.2-q12, is a secreted chemokine, which attracts macrophages during inflammation and metastasis. In an effort to discover additional polymorphism(s) in genes whose variant(s) have been implicated in asthma, we scrutinized the genetic polymorphisms in MCP3 to evaluate it as a potential candidate gene for asthma host genetic study. By direct DNA sequencing in twenty-four individuals, we identified four sequence variants within the 3 kb full genome including 1,000bp promoter region of MCP3; one in promoter region (-420T>C), three in intron (+136C>G, +563C>T, +984G>A) respectively. The frequencies of those four SNPs were 0.020 (-420T>C), 0.038 (+136C>G), 0.080 (+563C>T), 0.035 (+984G>A), respectively, in Korean population (n = 598). Haplotypes, their frequencies and linkage disequilibrium coefficients (|D'|) between SNP pairs were estimated. The associations with the risk of asthma, skin-test reactivity and total serum IgE levels were analyzed. Using statistical analyses for association of MCP3 polymorphisms with asthma development and asthma-related phenotypes, no significant signals were detected. In conclusion, we identified four genetic polymorphisms in the important MCP3 gene, but no significant associations of MCP3 variants with asthma phenotypes were detected. MCP3 variation/haplotype information identified in this study will provide valuable information for future association studies of other allergic diseases.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1479-1484
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• 2008

Protein tyrosine phosphatase (PTP) 1B is the superfamily of PTPs and a negative regulator of multiple receptor tyrosine kinases (RTKs). Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been proposed as a strategy for the treatment of type 2 diabetes and obesity. Recently, it has been reported that amentoflavone, a biflavonoid extracted from Selaginella tamariscina, inhibited PTP1B. In the present study, docking model between amentoflavone and PTP1B was determined using automated docking study. Based on this docking model and the interactions between the known inhibitors and PTP1B, we determined multiple pharmacophore maps which consisted of five features, two hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. Using receptor-oriented pharmacophore-based in silico screening, we searched the biflavonoid database including 40 naturally occurring biflavonoids. From these results, it can be proposed that two biflavonoids, sumaflavone and tetrahydroamentoflavone can be potent allosteric inhibitors, and the linkage at 5',8''-position of two flavones and a hydroxyl group at 4'-position are the critical factors for their allosteric inhibition. This study will be helpful to understand the mechanism of allosteric inhibition of PTP1B by biflavonoids and give insights to develop potent inhibitors of PTP1B.

• Genomics & Informatics
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• v.12 no.3
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• pp.114-120
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• 2014

Bone mineral density (BMD) is one of the quantitative traits that are genetically inherited and affected by various factors. Over the past years, genome-wide association studies (GWASs) have searched for many genetic loci that influence BMD. A recent meta-analysis of 17 GWASs for BMD of the femoral neck and lumbar spine is the largest GWAS for BMD to date and offers 64 single-nucleotide polymorphisms (SNPs) in 56 associated loci. We investigated these BMD loci in a Korean population called Korea Association REsource (KARE) to identify their validity in an independent study. The KARE population contains genotypes from 8,842 individuals, and their BMD levels were measured at the distal radius (BMD-RT) and midshaft tibia (BMD-TT). Thirteen genomic loci among 56 loci were significantly associated with BMD variations, and 3 loci were involved in known biological pathways related to BMD. In order to find putative functional variants, nearby SNPs in relation to linkage equilibrium were annotated, and their possible functional effects were predicted. These findings reveal that tens of variants, not a single factor, may contribute to the genetic architecture of BMD; have an important role regardless of ethnic group; and may highlight the importance of a replication study in GWASs to validate genuine loci for BMD variation.