• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.3
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• pp.235-239
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• 2006

Due to recent advances in genome sequencing, there has been a dramatic increase in the quantity of genetic information, which has lead to an even greater demand for a faster, more parallel expression system. Therefore, interest in cell-free protein synthesis, as an alternative method for high-throughput gene expression, has been revived. In contrast to in vivo gene expression methods, cell-free protein synthesis provides a completely open system for direct access to the reaction conditions. We have developed an efficient cell-free protein synthesis system by optimizing the energy source and S30 extract. Under the optimized conditions, approximately $650{\mu}g/mL$ of protein was produced after 2h of incubation, with the developed system further modified for the efficient expression of PCR-amplified DNA. When the concentrations of DNA, magnesium, and amino acids were optimized for the production of PCR-based cell-free protein synthesis, the protein yield was comparable to that from the plasmid template.

• The Korean Journal of Zoology
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• v.26 no.1
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• pp.19-28
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• 1983

Alkaline elution profiles showed that the frequency of DNA single strand breaks associated with DNA-protein crosslinks in cells treated with both an inducing dose of MMC $(MMC_1)$ and a challenge dose of MMC $(MMC_2)$ was slightly less than that in cells treated with MMC alone. The amount of unscheduled DNA synthesisi in cells treated with both $MMC_1$ and $MMC_2$ was greater than that in cells treated with MMC alone. This enhancement of exicision repair detected by UDS autoradiography and alkaline elution, was not observed, when cells were incubated with cyclohexmide between the two treatments of $MMC_1$ and $MMC_2$. These results suggest that MMC-damaged DNA from Chinses hamster cells is repaired by excision repair mechanisms that require de novo protein synthesis for enhancement, and that an inducible repair mechanism may exist in CHO cells.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1280-1285
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• 2004

Retron is a prokaryotic genetic element, producing a short single-stranded DNA covalently linked to RNA (msDNA-RNA) by a reverse transcriptase (RT). In retron EC83, msDNA is further processed at between the 4th and the $5^{th}$ nucleotides, leaving a 79 nucleotide-long single-stranded DNA as a final product. To investigate this site-specific cleavage in msDNA synthesis, we purified the RT protein of retron EC83. Initially, RT ORF was cloned under the tac promoter, but the expression was very poor largely because of poor translation. In order to facilitate translation, the nucleotide sequence for the first nine amino acids was randomized with synonymous codons. This change of downstream sequence of translational initiation codon greatly affected the efficiency of translation. We could isolate clones which greatly increased RT production, and their sequences were compared to those of the low producers. The overproduced protein was purified and was shown to have RT activity.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.749-752
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• 2013

Trehalose-tethered monomeric and dimeric berberines were synthesized in 50% and 30% from the reaction of berberrubine with 6-tosyl-${\alpha}$,${\alpha}^{\prime}$-trehalose and 6,6'-ditosyl-${\alpha}$,${\alpha}^{\prime}$-trehalose, respectively, and fully characterized by MS (HR and ESI) and NMR ($^1H$, $^{13}C$, COSY and HSQC). Spectrophotometric and spectrofluorimetric titrations indicated that compared with berberine, trehalose-tethered monomeric berberine had comparable DNA-binding affinity toward calf-thymus DNA, whereas trehalose-spaced dimeric berberine exhibited higher DNA-binding affinity. The potential application of these conjugates is also briefly discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.105-106
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• 2007

M-DNAs based on zinc and cobalt ions were formed at the conditions of $26^{\circ}C$, 76% humidity, atmosphere, and pH 8.0. Some process parameters in synthesis of M-DNA such as synthetic temperature, concentration of metal ions, and synthetic time were varied and the electrical properties were investigated by changes of the parameters. The electrical properties of M-DNA showed the dependences on synthetic temperature, concentration of metal ions and synthetic time. The I-V characteristics rapidly increased with each increase of the parameters.

• Toxicological Research
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• v.32 no.2
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• pp.95-102
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• 2016

In the recent years, noble nanoparticles have attracted and emerged in the field of biology, medicine and electronics due to their incredible applications. There were several methods have been used for synthesis of nanoparticles such as toxic chemicals and high energy physical procedures. To overcome these, biological method has been used for the synthesis of various metal nanoparticles. Among the nanoparticles, silver nanoparticles (AgNPs) have received much attention in various fields, such as antimicrobial activity, therapeutics, bio-molecular detection, silver nanocoated medical devices and optical receptor. Moreover, the biological approach, in particular the usage of natural organisms has offered a reliable, simple, nontoxic and environmental friendly method. Hence, the current article is focused on the biological synthesis of silver nanoparticles and their application in the biomedical field.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.160-164
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• 2004

In this study, we demonstrate for the first time a bio-inspired Cell-Microsystem to manipulate and detect living cells. Cultured retinal pigment epithelial cell line (ARPE-19) was directed to grow in a pre-defined Cell-Microsystem. The three-dimensional micropillars of 5 ${\mu}{\textrm}{m}$ in height and diameter of the Cell-Microsystem were fabricated. Inhibited DNA synthesis and transformed cell morphology were observed throughout the culture period. The demonstration of manipulating and detecting living cells by the surface topography is a new approach, and it will be very useful for the future design of cell-based biosensors and bioactuators.

• Korean Journal of Veterinary Research
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• v.23 no.1
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• pp.1-8
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• 1983

The purpose of the present study is to determine variations in synthesis of DNA in the nuclei of various elements of the golden hamster (Mesocricetus auratus) placenta with increasing gestational age from the eighth day post coitus to parturition. The method employed for such determination was autoradiography following injection of pregnant animals with tritiated thymidine. From the results reported, the following points are concluded. The mitotic activities of the endodermal cells of the visceral yolk sac and of the parietal yolk sac, the trophoblastic cells of the labyrinth and the trophospongium and the giant cells were decreased with increasing gestational age, The placentation was nearly completed by day 13 of pregnancy and the increase in size of labyrinth was by appositional growth from the trophospongial cells. It was considered that the inner trophoblastic cells in the vicinity of the fetal blood vessels were originated from the pure chorion. The interrelation among the various cells and the polyploidal giant cells in the placenta were discussed.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.107-115
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• 1997

We studied the effects of bile acids on the induction ofapoptosis in HepG2 human hepatocellular carcinoma cells. Treatment with either ursodeoxycholic acid (UDCA) or lithocholic acid (LCA) resulted in a dose- and time-dependent decrease in cell viability assessed by MTT assay. Both UDCA and LCA also induced genomic DNA fragmentation, a hallmark of apoptosis, indicating that the mechanism by which these bile acids induce cell death was through apoptosis. Cycloheximide, a protein synthesis inhibitor, blocked the apoptosis induced by these bile acids, implying that new protein synthesis may be required for the apoptosis. Intracellular $Ca^{2+}$ release blockers (dantrolene and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester) inhibited decreased cell viability and DNA fragmentation induced by these bile acids. Treatment of HepG2 cells with calcium ionophore A23l87 induced DNA fragmentation. These results suggest that UDCA and LCA induce apoptosis in the HepG2 cells and that the activation of intracellular $Ca^{2+}$ signals may play an important role in the apoptosis induced by these bile acids.

• BMB Reports
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• v.34 no.5
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• pp.463-471
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• 2001

The bark of Ulmus darvidiana var. japonica Nakai (UDN) has been used for a long time to cure inflammation in oriental medicine. In the present study, two types of extracts, Ulmus water-eluted fraction (UWF) and Ulmus ethanol-eluted fraction (UEF), were prepared from the UDN stem bark, and employed to test the extracts to see if they had anti-oxidative properties against hydroxyl radicals that could alter immune reactivity in mouse immune cells. Deoxyribose assay, DNA nicking assay, and glucose/glucose oxidase assay showed that both fractions had scavenging activity against oxygen free radicals at 50 mg/ml. In addition, hydroxyl radical-mediated apoptosis in mouse thymocytes was not protected by UEF treatment, but the apoptosis was protected by UWF at the same concentration. DNA synthesis and cytokine production that were induced in splenocytes by mitogens (Concanavalin A and lipopolysaccharide) were reduced by the addition of both fractions. These results indicate that both extracts that were prepared from the UDN stem bark have anti-oxidative activities, anti-apoptotic effects, and inhibitory effects on DNA synthesis and cytokine production in mouse immune cell cultures.