• BMB Reports
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• 제32권4호
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• pp.409-413
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• 1999

The cDNA encoding CMP-NeuAc:lactosylceramide ${\alpha}2$,3-sialyltransferase (GM3 synthase) was isolated from a human fetal brain cDNA library using sequence information obtained from amino acid sequences found in the conserved regions of the previously-cloned mouse GM3 synthase (mST3Gal V) and human sialyltransferases. The cDNA sequence included an open reading frame coding for 362 amino acids, and the primary structure of this enzyme predicted all the structural features characteristic of other sialyltransferases, including a type II membrane protein topology and both sialylmotifs. Comparative analysis of this cDNA with mST3Gal V showed 85% and 86% identity of the nucleotide and amino acid residues, respectively. The expression of this gene is highly restricted in both human fetal and adult tissues.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.134-141
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• 2015

The effect of a 60 Hz time-varying electric field was studied using a facing-electrode device (FED) and a coplanar-electrode device (CED) for further investigation of the genotoxicity of 60 Hz time-varying magnetic field (MF) from preceding research. Neither a single 30-minute exposure to the CED or to the FED had any obvious biological effects such as DNA double strand break (DSB) and apoptosis in cancerous SCC25, and HeLa cells, normal primary fibroblast IMR90 cells, while exposures of 60 Hz time-varying MF led to DNA damage with induced electric fields much smaller than those used in this experiment. Nor did repetitive exposures of three days or a continuous exposure of up to 144 hours with the CED induce any DNA damage or apoptosis in either HeLa or IMR90 cells. These results imply that the solitary electric field produced by time-varying MF is not a major cause of DSBs or apoptosis in cancer or normal cells.

• 생태와환경
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• 제39권2호통권116호
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• pp.265-270
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• 2006

The nucleotide sequence variations of mitochondrial DNA were investigated to understand genetic differentiation for five different Pungitius kaibarae populations at five study sites from selected four streams flowing into the East Sea. The complete sequences of mtDNA control regions of them were determined the constant sites 342 bp and variable sites 183 bp including parsimony infromative sites 122 bp. Based on the phylogenetic tree, five populations were monophyletic unit (97% MPand 100% NJ) and separated two groups (Myongpa-Songhuen stream group and others group). The population of Baebong stream (82nd bp, G-A) consistently formed them of the Jasan stream into a monophyletic unit even though it is closer then Myongpa stream (99th bp, T-C) from the Baebong stream. Further studies on the molecular phylogeny for the primary freshwater fish are needed to establish for the fish biodiversity conservation in mountainous and upland streams.

• 미생물학회지
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• 제38권2호
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• pp.103-106
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• 2002

사상균류의 세포자체로부터 직접 PCR을 하는 방법은 세포벽 파괴의 어려움 때문에 모든 곰팡이에 적용될 수 없다. 극초단파 조사는 사상균류의 DNA를 추출함에 있어서 그 유용함이 이미 검중된 바 있는데, 본 논문에서는 극초단파 조사를 이용하여 Aspergillus nidulans의 포자로부터 손쉽게 주형 DNA를 얻어 PCR증폭하는 방법을 소개하고자 한다. 본 실험에서는 극초단파 조사시간과 PCR에 필요한 주형 DNA의 양 등을 최적화하였으며, 이렇게 수행된 PCR결과는 single copy유전자를 대상으로도 약 3 kb크기의 산물가지 증폭 가능하여, 형질전환체를 선별하기에 충분한 크기의 산물들도 효과적으로 얻어짐을 보여주었다. 따라서 이 방법은A. nidulans의 형질전환체를 보다 손쉽게, 시간을 절약하여 선별할 수 있는 효과적인 방법이라 생각된다.

• BMB Reports
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• 제43권3호
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• pp.176-181
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• 2010

The primary sigma factor ($\sigma^{A}$) of Staphylococcus aureus, a potential drug target, was little investigated at the structural level. Using an N-terminal histidine-tagged $\sigma^{A}$ (His-$\sigma^{A}$), here we have demonstrated that it exits as a monomer in solution, possesses multiple domains, harbors primarily $\alpha$-helix and efficiently binds to a S. aureus promoter DNA in the presence of core RNA polymerase. While both N- and C-terminal ends of His-$\sigma^{A}$ are flexible in nature, two Trp residues in its DNA binding region are buried. Upon increasing the incubation temperature from 25$^{\circ}$ to 40$^{\circ}C$, $\sim$60% of the input His-$\sigma^{A}$ was cleaved by thermolysin. Aggregation of His-$\sigma^{A}$ was also initiated rapidly at 45$^{\circ}C$. From the equilibrium unfolding experiment, the Gibbs free energy of stabilization of His-$\sigma^{A}$ was estimated to be +0.70 kcal $mol^{-1}$. The data together suggest that primary sigma factor of S. aureus is an unstable protein. Core RNA polymerase however stabilized $\sigma^{A}$ appreciably.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2873-2876
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• 2010

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. Previous studies have shown that one of the primary causes of increased brain iron may be the release of excess iron from intracellular iron storage molecules. In this study, we attempted to characterize the oxidative damage of DNA induced by the reaction of ferritin with $H_2O_2$. When DNA was incubated with ferritin and $H_2O_2$, DNA strand breakage increased in a time-dependent manner. Hydroxyl radical scavengers strongly inhibited the ferritin/$H_2O_2$ system-induced DNA cleavage. We investigated the generation of hydroxyl radical in the reaction of ferritin with $H_2O_2$ using a chromogen, 2,2'-azinobis-(2-ethylbenzthiazoline-6-sulfonate) (ABTS), which reacted with ${\cdot}OH$ to form $ABTS^{+\cdot}$. The initial rate of $ABTS^{+\cdot}$ formation increased as a function of incubation time. These results suggest that DNA strand breakage is mediated in the reaction of ferritin with $H_2O_2$ via the generation of hydroxyl radicals. The iron-specific chelator, deferoxamine, also inhibited DNA cleavage. Spectrophotometric study using a color reagent showed that the release of iron from $H_2O_2$-treated ferritin increased in a time-dependent manner. Ferritin enhanced mutation of the lacZ' gene in the presence of $H_2O_2$ when measured as a loss of $\alpha$-complementation. These results indicate that ferritin/$H_2O_2$ system-mediated DNA cleavage and mutation may be attributable to hydroxyl radical generation via a Fenton-like reaction of free iron ions released from oxidatively damaged ferritin.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권5호
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• pp.509-517
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• 2008

DNA 손상 치유 유전자 연구를 기초로 한 임상적 접근이 새로운 치료방법으로 떠오르고 있다. 많은 연구들이 중요한 DNA 수복유전자의 다형성을 찾아내어 각각의 단백질의 활동성에 대한 영향을 알아내고 특정한 치료법을 찾아내고 임상적 적용을 시도하고 결과를 평가하였다. 그 결과 암 치료에서 정상 세포와 암세포에서 DNA 수복 유전자의 발현 분석은 화학요법이나 방사선 치료에서 개인맞춤형 치료법을 가능하게 하고 있다. 예를 들어, NER이 결핍된 종양은 cisplatin 치료에 민감성을 나타내고, MMR 결핍세포는 알킬화 화학요법 약제에 높은 내성을 나타낸다. 선천성 비폴립성 결장암과 같은 MMR 결손종양 또한 알킬화 화학요법 약제에 의한 치료에 내성을 가진다. 신경교종(glioma)에서 MGMT 유전자 프로모터가 흔히 메틸화되는데 이것은 유전자 발현이 억제되고 알킬화 화학요법제에 대한 반응성을 증가시킨다. 향후 구강악안면외과 영역에서도 구강암의 발생의 위험성을 증가시킬 수 있는 더 많은 DNA 수복 유전자의 다형성을 발굴하고 임상적으로 개인맞춤형 치료법을 개발하고 적용할 수 있는 많은 연구가 필요할 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제45권1호
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• pp.11-15
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• 2020

Background: There have been various studies to investigate the mechanisms of DNA damage from low-energy electrons. To understand the mechanism of these strand breaks, it is necessary to investigate the dissociation mechanism of the DNA constituents, that is, bases, sugars, and phosphates. Materials and Methods: We studied the dissociation of thymine base upon interaction with low-energy electrons. For this experiment, thymine powder was pressed onto the indium base and irradiated by 5 eV electrons. Results and Discussion: Non-irradiated and irradiated thymine samples were compared and analyzed using the X-ray photoelectron spectroscopic technique to analyze the dissociation patterns of the molecular bonds after low-energy electron irradiation of thymine. Conclusion: With 5 eV electron irradiation, C-C and N-C = O bonds are the primary dissociations that occur in thymine molecules.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.70.2-71
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• 2003

Quinolone resistance in Streptococcus pneumoniae is related to mutations in the DNA gyrase and topoisomerase IV genes. DW-286a displayed potent activity against S. pneumoniae C9211 (MIC, 0.015 ${\mu}$g/ml) compared with gemifloxacin (MIC, 0.06 ${\mu}$g/ml). This study was performed to analyze the ability of DW-286a to cause resistance development in S. pneumoniae and to establish whether DNA gyrase or topoisomerase IV is primary target. DW-286a resistant mutants of S. pneumoniae C9211 were generated by stepwise selection at increasing drug concentration. (omitted)

• 생명과학회지
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• 제13권3호
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• pp.241-247
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• 2003

DNA 손상 유발을 위해 cisplatin, mitomycin 그리고 adriamycin을 농도별로 처리하여 세포독성 효과 및 세포주기 분포를 조사하였다. 이들 약제중 adriamycin의 감수성이 가장 높았으며 특히 $Ku80^{-/-}MEFs$가 현저한 세포독성 감수성 효과를 나타내었다. DNA 회복과 관련된 S phase의 분포도를 알아보기 위하여 adriamycin을 처리한 결과 DNA-$PKcs^{-/-}MEFs$와 $Ku80^{-/-}MEFs$ 모두에서 S phase는 대조군과 비슷하게 나타났다. 그리고 DNA$PKcs^{-/-}MEFs$에 adriamycin 처리시 6시간 경과 후 $G_2$/M phase가 증가되었으나 30시간 경과시 정상으로 회복되었다. 그러나 $Ku80^{-/-}MEFs$는 6시간 경과 이후 36시간 경과시 까지 $G_2$/M phase가 지속적으로 증가하다 결국 사멸되었다. 따라서 Ku80는 세포주기 조절 유전자의 발현을 위해 필수적인 단백질이며 Ku80의 결핍은 $G_2$M phase에서 다음 단계로의 세포주기 변화를 상실하여 사멸하게 된다. 그러므로 $Ku80^{-/-}MEFs$가 대조군과 다른 반응을 나타내는 것은 DNA 회복정도의 차이에서 오는 것이 아니라 세포주기 조절유전자 발현의 차이에서 오는 것으로 사료된다.