• The Korean Journal of Zoology
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• v.25 no.2
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• pp.55-62
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• 1982

DNA synthesis, unscheduled DNA synthesis, excision of pyrimidine dimers and phtoreactivation were determined in UV-irradiated differentiating muscle cells at various times of primary culture of 12 day chick embryos and results obtained were as follows. The rates of UV-induced unscheduled DNA synthesis were increased as increase of UV dose. And the rates were gradually decreased as the increase of time after culture, but at higher doses the decreasing tendency was remarkable. The patterns of DNA replication were changed drastically as a function of time so that in the seven day cultures the rate of $^3$H-thymidine incorporation was found to be 0.2% of the original activity. The pattern of inhibition of DNA replication by UV damage demonstrated that in cells of earlier stages there were no remarkable changes, but in cells of later stages there was significant fluctuation. Photoreactivation and the excision of pyrimidine dimer in the one day cultures showed that photoreactivation occurred immediately after UV-irradiation, but excision of pyrimidine dimer was gradually and slowly occurred. These results indicate that the differentiation of embryonic muscle cells accompanies the gradual reduction of DNA replication and unscheduled DNA synthesis, and that the photoreactivation is rapid process compared to excision repair.

• Journal of Microbiology and Biotechnology
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• v.17 no.6
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• pp.1045-1048
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• 2007

Two genes, dps encoding decaprenyl diphosphate synthase and dxs encoding 1-deoxy-D-xylulose 5-phosphate synthase, were isolated from Rhizobium radiobacter ATCC 4718. DNA sequencing analysis of the dps and dxs genes revealed an open reading frame of 1,077 bp and 1,920 bp, respectively. The heterologous expression in Escherichia coli BL21(DE3) was carried out in order to identify their functions. Recombinant E. coli BL21(DE3) harboring the dps gene produced $CoQ_{10}$ as well as $CoQ_8$ and $CoQ_9$, whereas E. coli harboring only the dxs gene produced more $CoQ_8$ compared with the wild-type E. coli. Additionally, the coexpression of dps and dxs genes in E. coli was carried out. The recombinant E. coli harboring only the dps gene produced $0.21{\pm}0.04\;mg/l$ of $CoQ_{10}$, whereas the coexpressed E. coli with dps and dxs genes produced $0.37{\pm}0.07\;mg/l$ of $CoQ_{10}$. HPLC analysis also showed that the $CoQ_{10}$ fraction (100% of the total CoQs distribution) was increased from $15.86{\pm}0.66%$ (only dps) to $29.78{\pm}1.80%$ (dps and dxs).

• The Korean Journal of Zoology
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• v.22 no.2
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• pp.81-93
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• 1979

Metabolic changes of early mouse embryos treated with progesterone were investigated in order to elucidate the mode of action of progesterone on embryogenesis in vitro. The embryos were cultured, and labelled with radioactive precursors of macromolecules for certain periods in the absence or presence of various concentrations of progesterone by employing the microtube culture technique. The changes of transport and macromolecular synthesis systems of the embryos were examined by measuring the amounts of uptake and incorporation of the precursors. The results obtained were as follows: 1. Progesterone stimulated markedly the uptake of amino acids, but rather suppressed their incorporation by embryonic cells. 2. Progesterone suppressed both the uptake and incorporation of nucleotide precursors (uridine and thymidine) by embryonic cells. 3. Progesterone penetrated into the embryonic cell membranes and was taken up by them. The present results seem to indicate that the inhibition of the progesterone on the mammalian embryogenesis in vitro may not be directly related to the membrane transport system. They seem to imply that progesterone would penetrate into the embryonic cells and may directly block the biosynethetic pathways of macromolecules, and so lead to the inhibition of the embryogenesis in vitro.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.119-125
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• 2006

To understand the comprehensive mechanisms of biological function for insulin-like growth factor-I (IGF-I) in vertebrates, we have investigated the cDNA sequence of this gene in the korean rockfish (Sebastes schlegeli). The mature form of korean rockfish IGF-I was found to be comprised of 67 amino acid residues, showing about a 7 kDa molecular weight. In this study, we used the polymerase chain reaction (PCR) to obtain a korean rockfish IGF-I (KR IGF-I) cDNA fragment, and methods of rapid amplification of cDNA ends (RACE) to obtain a full length of the KR IGF-I sequence. The KR IGF-I encoded for a predicted amino acid sequence showed identities of 93.6 %, 90.7 %, and 85.4 % in comparison with flounder, chinook salmon, and human IGF-I, respectively. To obtain recombinant biologically active polypeptides, korean rockfish B-C-A-D domains were amplified using the PCR, then the isolated cDNA was expressed in the E. coli BL21(DE3). The recombinant KR IGF-I protein biological function was measured by stimulation of [$^3H$] thymidine incorporation, suggesting the cDNA codes for the korean rockfish proIGF-I.

• BMB Reports
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• v.51 no.9
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• pp.437-443
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• 2018

Non-homologous end joining (NHEJ), and to a lesser extent, the error-free pathway known as homology-directed repair (HDR) are cellular mechanisms for recovery from double-strand DNA breaks (DSB) induced by RNA-guided programmable nuclease CRISPR/Cas. Since NHEJ is equivalent to using a duck tape to stick two pieces of metals together, the outcome of this repair mechanism is prone to error. Any out-of-frame mutations or premature stop codons resulting from NHEJ repair mechanism are extremely handy for loss-of-function studies. Substitution of a mutation on the genome with the correct exogenous repair DNA requires coordination via an error-free HDR, for targeted transgenesis. However, several practical limitations exist in harnessing the potential of HDR to replace a faulty mutation for therapeutic purposes in all cell types and more so in somatic cells. In germ cells after the DSB, copying occurs from the homologous chromosome, which increases the chances of incorporation of exogenous DNA with some degree of homology into the genome compared with somatic cells where copying from the identical sister chromatid is always preferred. This review summarizes several strategies that have been implemented to increase the frequency of HDR with a focus on somatic cells. It also highlights the limitations of this technology in gene therapy and suggests specific solutions to circumvent those barriers.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.196-201
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• 2010

The phenethyl ester of caffeic acid (CAPE), an active component of honeybee propolis extract, is shown to inhibit cancer growth previously. However, studies on human ovarian cancer are largely obscure. This study evaluated the effects of CAPE as a potential anti-proliferative and pro-apoptotic agent in the human ovarian cancer line, OVCAR-3. CAPE treated OVCAR-3 cells showed inhibition of cell viability and proliferation in a dose-dependent manner by WST-1 assay, LDH assay and bromodeoxyuridine (BrdU) incorporation assay. Furthermore, CAPE-mediated OVCAR-3 cell growth inhibition was associated with apoptotic changes as evident by cell cycle arrest and accumulation of cells in the apoptotic phase and DNA fragmentation. Taken together, CAPE inhibits cell proliferation via DNA synthesis reduction and induces apoptotic cell death via DNA damage, thus elucidating a novel, plausible mechanism of CAPE anti-tumorigenic property in OVCAR-3 cells.

• BMB Reports
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• v.33 no.3
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• pp.268-275
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• 2000

In contrast to the pyrimidine (6-4)pyrimidone photoproduct [(6-4) adduct], its Dewar valence isomer (Dewar product) is low mutagenic and produces a broad range of mutations with a 42 % replicating error frequency. In order to determine the origin of the mutagenic property of the Dewar product, we used experimental NMR restraints and molecular dynamics to determine the solution structure of a Dewar·lesion DNA decamer duplex, which contains a mismatched base pair between the 3'-T residue and an opposed G residue. The 3'-T of the Dewar lesion forms stable hydrogen bonds with the opposite G residue. The helical bending and unwinding angles of the DW/GA duplex, however, are much higher than those of the DW/AA duplex. The stable hydrogen bonding of the G 15 residue does not increase the thermal stability of the overall helix. It also does not restore the distorted backbone conformation of the DNA helix that is caused by the forming of a Dewar lesion. These structural features implicate that no thermal stability, or conformational benefits of G over A opposite the 3'-T of the Dewar lesion, facilitate the preferential incorporation of an A. This is in accordance with the A rule during translesion replication and leads to the low frequent $3'-T{\rightarrow}C$ mutation at this site.

• Korean Journal of Veterinary Service
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• v.37 no.1
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• pp.29-33
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• 2014

This study aimed at finding a fast, sensitive, and efficient protocol for molecular identification of intracellular protozoa Toxoplasma (T.) gondii. For molecular detection of T. gondii, we developed a polymerase chain reaction coupled with dot blot hybridization assay (PCR/DBH). For DBH analysis, the amplified DNA of T. gondii tachyzoite was labeled by incorporation of digoxigenin. The DBH assay alone was capable of detecting down to $1{\times}10^4$ pg of T. gondii genomic DNA. The PCR alone was capable of detecting down to $1{\times}10^3$ pg of T. gondii genomic DNA, whereas the PCR/DBH assay was capable of detecting down to $1{\times}10^2$ pg of T. gondii genomic DNA, indicating that sensitivity of the PCR/DBH method was approximately 10 to 100 times higher than PCR or DBH alone. Our PCR/DBH assay will be useful for confirming the presence of T. gondii on the samples and differentiating T. gondii infection from other intracellular protozoa infections.

• Korean Journal of Plant Resources
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• v.14 no.3
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• pp.235-240
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• 2001

Polymerase chain reaction (PCR) is used in a wide array of researches in plant molecular genetics and breeding. However, considerable time and cost are still required for the preparation of DNA suitable for reliable PCR results, especially in plant species containing high amounts of polyphenols. To reduce time and effort for PCR-based analysis, a simplified but reliable method was developed by a combinational employment of a simple and fast DNA extraction procedure and BLOTTO (Bovine Lacto Transfer Technique Optimizer) in reaction mixture. Genomic DNAs prepared by one-step extraction method from recalcitrant plant species such as Rubus coreanus, apple, grape and lettuce were successfully amplified by random primers in the reaction mixture containing 2 to 4% BLOTTO. Successful amplification of ${\gamma}$-TMT transgene in lettuce transformants by the specific primers was also achieved in the same condition, making rapid screening of positive transformants possible. Our results suggest that use of a simple DNA extraction procedure and incorporation of BLOTTO in reaction mixture in combination can reduce time and effort required for the analyses of a large number of germplasms and transformants by PCR-based techniques.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2769-2772
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• 2009