• 방송공학회논문지
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• 제16권5호
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• pp.824-833
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• 2011

In this paper, using the Rec. ITU-R P.1546 explaining a propagation prediction model in the VHF and UHF bands, we propose the analytical methodology for calculating the service distance and field strength for analogue and digital TV receivers. From the derived formulation of the receiver field strength, some computation results are presented and discussed in terms of the equivalent level of service caused by analogue to digital TV conversion. The suggested method is also applicable to the analysis of frequency coordination or compatibility from unwanted signal in VHF and UHF bands.

• 한국식품과학회지
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• 제19권3호
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• pp.212-219
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• 1987

재래종 적색 자두 (Prunus salicina)에서 효소를 추출하여 4종류의 polyphenol화합물과 반응시켜 얻어진 갈변반응 생성물에 대하여 Bacillus subtilis H17과 M45를 이용한 rec-assay와 Salmonella typhimurium TA98과 TA100 두 균주를 이용한 Ames test, 그리고 calfcthymus DNA를 이용하는 DNA절단시험을 이용하여 돌연변이원성과 돌연변이 억제작용을 조사하였다. 포자 rec-assay 에서는 pyrogallol, hydroxyhydroquinone, 3,4-dihydroxytoluene, chlorogenic acid 의 갈변반응 생성물은 모두 DNA손상능력이 없었으며 8가지 금속이온 중 ${Zn}^{2+}$과 ${Ni}^{2+}$의 첨가로 고초균 DNA손상에 약한 영향을 나타내었다. DNA절단시험 결과 4종류 갈변반응 생성물 모두 DNA절단작용이 없었으며 금속이온의 영향에 있어서는 pyrogallol 갈변반응 생성물이 ${Cu}^{2+}$의 영향을 받아 ${Cu}^{2+}$의 농도가 증가함에 따라 강한 절단작용을 나타내었으며 3,4-dihydroxytoluene 과 hydroxyhydroquinone갈변반응 생성물은 금속이온의 영향을 전혀 받지 않았다. 또한 chlorogenic acid갈변반응 생성물은 DNA 절단을 억제하는 효과를 나타내었다. Ames test에서는 4가지 갈변반응 생성물 모두 변이원성은 없었으며 benzo$[{\alpha}]$pyrene을 사용한 변이원성 억제작용 실험결과 benzo$[{\alpha}]$pyrene의 활성을 강하게 억제하는 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제39권1호
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• pp.70-76
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• 2011

Weissella 속 유산균 검출의 차이를 이용한 한국산 및 중국산 김치 판별의 가능성 검토를 위하여 Weissella 속 9종 균주의 PCR 검출법을 개발하였다. 종(species) 수준에서의 Weissella 속 균주의 특이적 PCR 검출을 위한 primer는 recN 유전자의 염기서열을 이용하여 선정하였으며, 김치로부터 W. cibaria, W. confusa, W. koreensis, W. soli를 모두 검출하기 위해서는 20 ng template DNA가 필요한 것으로 나타났다. 한국산 김치시료로부터는 W. cibaria, W. confusa, W. koreensis가 높은 빈도로 검출되었지만, W. soli는 검출되지 않았다. 한편 중국산 김치시료로부터는 이들 4종의 Weissella 속 균주들이 모두 검출되었다. 본 연구자들이 개발한 W. soli 특이적 PCR 검출은 현시점에서 중국산 김치의 원산지 판별법으로 적용되기에는 한계점을 가지고 있지만, 미생물 군집의 차이를 이용한 새로운 과학적 검증법이 제시되어 그 가능성이 검토되었다는 점에서 의의를 가지고 있다.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.199-211
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• 2021

Equine chorionic gonadotropin (eCG), produced by the endometrial cups of the placenta after the first trimester, is a specific glycoprotein that displays dual luteinizing hormone (LH)-like and follicle-stimulating hormone (FSH)-like effects in non-equid species. However, in equidaes, eCG exhibits only LH-like activity. To identify the specific biological functions of glycosylated sites in eCG, we constructed the following site mutants of N- and O-linked glycosylation: eCGβ/αΔ56, substitution of α-subunit⁵⁶ N-linked glycosylation site; eCGβ-D/α, deletion of the O-linked glycosylation sites at the β-subunit, and eCGβ-D/αΔ56, double mutant. We produced recombinant eCG (rec-eCG) proteins in Chinese hamster ovary suspension (CHO-S) cells. We examined the biological activity of rec-eCG proteins in CHO-K1 cells expressing the eLH/CG receptor and found that signal transduction activities of deglycosylated mutants remarkably decreased. The EC₅₀ levels of eCGβ/αΔ56, eCGβ-D/α, and eCGβ-D/αΔ56 mutants decreased by 2.1-, 5.6-, and 3.4-fold, respectively, compared to that of wild-type eCG. The Rmax values of the mutants were 56%-80% those of wild-type eCG (141.9 nmol/10⁴ cells). Our results indicate that the biological activity of eCG is greatly affected by the removal of N- and O-linked glycosylation sites in cells expressing eLH/CGR. These results provide important information on rec-eCG in the regulation of specific glycosylation sites and improve our understanding of the specific biological activity of rec-eCG glycosylation sites in equidaes.

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1749-1759
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• 2018

Recombinant (rec) prion protein (PrP) is an extremely useful resource for studying protein misfolding and subsequent protein aggregation events. Here, we report mass production of high-purity rec-polypeptide encoding the C-terminal globular domain of PrP; (90-230) for human and (89-231) for murine PrP. These proteins were expressed as His-tagged fusion proteins in E. coli cultured by a high cell-density aerobic fermentation method. RecPrPs recovered from inclusion bodies were slowly refolded under reducing conditions. Purification was performed by a sequence of metal-affinity, cation-exchange, and reverse-phase chromatography. The current procedure yielded several dozens of milligrams of recPrP per liter with >95% purity. The purified recPrPs predominantly adopted an ${\alpha}$-helix-rich conformation and were functionally sufficient as substrates to measure the seeding activity of human and animal prions. Establishment of a procedure for high-level production of high-purity recPrP supports the advancement of in vitro investigations of PrP including diagnosis for prion diseases.

• The Plant Pathology Journal
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• 제26권3호
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• pp.223-230
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• 2010

The Burkholderia cepacia complex isolates causing bacterial fruit rot of apricot were characterized by speciesspecific PCR tests, recA-HaeIII restriction fragment length polymorphism (RFLP) assays, rep-PCR genomic fingerprinting, recA gene sequencing, and multilocus sequence typing (MLST) analysis. Results indicated that the isolates Bca 0901 and Bca 0902 gave positive amplifications with primers specific for B. vietnamiensis while the two bacterial isolates showed different recA-RFLP and rep-PCR profiles from those of B. vietnamiensis strains. In addition, the two bacterial isolates had a higher proteolytic activity compared with that of the non-pathogenic B. vietnamiensis strains while no cblA and esmR marker genes were detected for the two bacterial isolates and B. vietnamiensis strains. The two bacterial isolates were identified as Burkholderia seminalis based on recA gene sequence analysis and MLST analysis. Overall, this is the first characterization of B. seminalis that cause bacterial fruit rot of apricot.

• 한국어병학회지
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• 제22권3호
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• pp.391-400
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• 2009

Genetic identification of 17 fish-derived Aeromonas strains was attempted using 5 housekeeping genes. 16S rRNA, gyrB, rpoD, dnaJ and recA genes from the 17 strains were amplified, and total of 85 amplicons were sequenced. DNA sequences of the strains and type strains of the 17 Aeromonas homology groups were used for genetic identification and phylogenetic analyses. None of the strains was identified as a single species using the 16S rRNA gene, showing the same identities (average = 99.7%) with several Aeromonas species. According to gyrB, rpoD, dnaJ, and recA, 9 strains and RFAS-1 used in this study were identified as A. hydrophila and A. salmonicida, respectively. However, the other strains were closely related to 2 or more Aeromonas species (i.e., A. salmonicida, A. veronii, A. jandaei, A. media and A. troda) depending on the genetic marker used. In this study, gyrB, rpoD, dnaJ and recA gene sequences proved to be advantageous over 16S rRNA for the identification of field Aeromonas isolates obtained from fish. However, there are discrepancies between analyses of different phylogenetic markers, indicating there are still difficulties in genetic identification of the genus Aeromonas using the housekeeping genes used in this study. Advantages and disadvantages of each housekeeping gene should be taken into account when the gene is used for identification of Aeromonas species.

• 생약학회지
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• 제28권3호
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• pp.149-155
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• 1997

Antaeum(ATE) has been used as a prescription for threatened abortion, associated with pregnancy in traditional medicine. Because gravida could be administered ATE for a long period, its administration might cause a harmful effect on fetus and gravida during the pregnancy. This study aimed to determine whether exposure to ATE caused mutagenicity or hepatotoxicity during the pregnant period. For mutagenicity test of ATE, Salmonella typhimurium and Bacillus subtilis were used as indications for DNA damage. In the Ames test, Samonella typhimurium TA98 and TA100 were used for mutagenicity testing, and the number of histidine revertants was measured. In Rec-assay, Bacillus subtilis H $17(Rec^+)$ and $M-45(Rec^-)$ strains were used to clarify the DNA damage property. In the SOS umu test, Salmonella typhimurium TA15335 containing plasmid pSK1002 was used as a tester strain, and we monitored the levels of umu operon expression by measuring the ${\beta}-galactosidase$ activity. From the tested results, ATE did not show DNA damage and mutagenicity. On the other hand, hepatotoxicity of ATE to female ICR mice was monitored by the measurements of s-GOT, s-GPT and LDH activities after oral feeding for 15 days. ATE did not show significant change of s-GOT, s-GPT and LDH activities in mice sera.

• Molecules and Cells
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• 제45권11호
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• pp.820-832
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• 2022

As a potential candidate to generate an everlasting cell source to treat various diseases, embryonic stem cells are regarded as a promising therapeutic tool in the regenerative medicine field. Cohesin, a multi-functional complex that controls various cellular activities, plays roles not only in organizing chromosome dynamics but also in controlling transcriptional activities related to self-renewal and differentiation of stem cells. Here, we report a novel role of the α-kleisin subunits of cohesin (RAD21 and REC8) in the maintenance of the balance between these two stem-cell processes. By knocking down REC8, RAD21, or the non-kleisin cohesin subunit SMC3 in mouse embryonic stem cells, we show that reduction in cohesin level impairs their self-renewal. Interestingly, the transcriptomic analysis revealed that knocking down each cohesin subunit enables the differentiation of embryonic stem cells into specific lineages. Specifically, embryonic stem cells in which cohesin subunit RAD21 were knocked down differentiated into cells expressing neural alongside germline lineage markers. Thus, we conclude that cohesin appears to control the fate determination of embryonic stem cells.

• Reproductive and Developmental Biology
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• 제29권2호
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• pp.69-73
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• 2005

The hematopoietic growth factor erythropoietin (EPO) is required for the maintenance, proliferation, and differentiation of the stem cells that produce erythrocytes. To analyse the biological activity of the recombinant human EPO (rec-hEPO), we have cloned the EPO cDNA and genomic DNA and produced rec-hEPO in the CHO cell lines. The growth and differentiation of EPO-dependent human leukemic cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of rec-hEPO. MIT assay values were increased by survival of F36E cells at 24h or 72h. The hematocrit and RBC values were increased by subcutaneous injection of 20 IU (in mice) and 100IU(in rats) rec-hEPO. Hematocrit values remarkably increased at $13.2\%$ (in mice) and $12.2\%$ (in rats). The pharmacokinetic behavior with injection of 6 IU of rec-hEPO remained detectable after 24 h in all mice tested. The highest peat appeared at 2h after injection. The long half-life of rec-hEPO is likely to confer clinical advantages by allowing less frequent dosing in patients treated for anemia. These data demonstratethat ree-hEPO produced in this study has a potent activity in vivo and in vitro. The results also suggest that biological activity of ree-hEPO could be remarkably enhanced by genetic engineering that affects the potential activity, including mutants with added oligosaccharide chain and designed to produce EPO-EPO fusion protein.