• Journal of Life Science
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• v.28 no.11
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• pp.1268-1276
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• 2018

The cytidine analog decitabine (DEC) acts as a nucleic acid synthesis inhibitor, whereas ammonium pyrrolidine dithiocarbamate (PDTC) is an inhibitor of nuclear factor-${\kappa}B$. The aim of this study was to investigate the possible synergistic inhibitory effect of these two inhibitors on proliferation of human gastric cancer AGS cells. The inhibitory effect of PDTC on AGS cell proliferation was significantly increased by DEC in a concentration-dependent manner, and this inhibition was associated with cell cycle arrest at the G2/M phase and the induction of apoptosis. This induction of apoptosis by the co-treatment with PDTC and DEC was related to the induction of DNA damage, as assessed by H2AX phosphorylation. Further studies demonstrated that co-treatment with PDTC and DEC induced the disruption of mitochondrial membrane potential, increased the generation of intracellular reactive oxygen species (ROS) and the expression of pro-apoptotic Bax, and down-regulated the expression of anti-apoptotic Bcl-2, ultimately resulting in the release of cytochrome c from the mitochondria into the cytoplasm. Co-treatment with PDTC and DEC also activated caspase-8 and caspase-9, which are representative caspases of the extrinsic and intrinsic apoptosis pathways. Co-treatment also activated caspase-3, which was accompanied by proteolytic degradation of poly (ADP-ribose) polymerase. Taken together, these data clearly indicated that co-treatment with PDTC and DEC suppressed the proliferation of AGS cells by increasing DNA damage and activating the ROS-mediated extrinsic and intrinsic apoptosis pathways.

• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.537-544
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• 2008

Polymerase chain reaction (PCR) can detect bacteria more rapidly than conventional plate counting. However DNA-based assays cannot distinguish between viable and dead cells due to persistence of DNA after cells have lost their vitality. Recently, propidium monoazide (PMA) treatment has been introduced. The purpose of this study is to evaluate the applicability of the PMA treatment and real-time PCR method for cell counting in comparison with plate counting and to evaluate the antibacterial efficacy of 2% CHX on E. faecalis using PMA treatment in combination with real-time PCR. Firstly, to elucidate the relationship between the proportion of viable cells and the real-time PCR signals after PMA treatment, mixtures with different ratios of viable and dead cells were used. Secondly, relative difference of viable cells using PMA treatment in combination with real-time PCR was compared with CFU by plate counting. Lastly, antibacterial efficacy of 2% CHX on E. faecalis was measured using PMA treatment in combination with real-time PCR. The results were as follows : 1. Ct value increased with decreasing proportion of viable E. faecalis. 2. There was correlation between viable cells measured by real-time PCR after PMA treatment and CFU by plate counting until Optical density (OD) value remains under 1.0. However, viable cells measured by real-time PCR after PMA treatment have decreased at 1.5 of OD value while CFU kept increasing. 3. Relative difference of viable E. faecalis decreased more after longer application of 2% CHX.

• Parasites, Hosts and Diseases
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• v.35 no.2
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• pp.119-126
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• 1997

Acanthnmoebn sp. YM-4 is simitar to A. culbertsoni based upon morphological characteristics of trophozoites and cysts. However, based on other characteristics, pathogenicity to mice, in uitro cytotoxicity and isoenzyme patterns, Acanthomoebo sp. YM- 4 was quite different from A. culbertsoni. Restriction fragment length polymorphism (RFLP) analysis of mtDNA is useful in the classification of members belonging to the genus Acanthcmoebn. Therefore, in this study, RFLP analysis of Acnnthcmoeba mtDNAs was accomplished using five restriction enzymes: Hnelll, Hinull, Clcl, Pudl and ScE. Each restriction enzyme produced approximately 3-15 fragments (range: from 0:6 kip to 34.4 kbp) . The mtDNA genome size, calculated by the summation of restriction fragments, averaged 46.4 kbp in Acnnthamoeba sp. YM-4,48.3 kbp in A. culbertsoni and 48.8 kbp in A. polyphaic, respectively. Digested mtDNA fragments of Accnthcmoeba sp. YM-4 contained nine and seven same size fragments, respectively, from a total of 67 and 69 fragments observed in A. culbertsoni and A. polyphcgn. An estimate of the genetic divergence was 10.1% between Acanthamoebc sp. YM-4 and A. culbertsoni, and 9.9% between Acanthamoebn sp. YM-4 and A. polyphcga.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.230-234
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• 2002

To describe characteristics of a hemolysin in mosquitocidal Bacillus thuringiensis subsp. gyangiensis strain 21-2, Escherichia coli HB101 was transformed with a gene encoding hemolysin in the strain 21-2. Transformant 47 con-tained 2.5 kb DNA was selected by ELISA, immunoblot and DNA electrophoresis. Transformant 47-5 was recon-structed after digestion of the 2.5 kb DNA with Hind m. Transformant 47-5 contained 1.8 kb DNA and expressed 23 kDa Protein which had mosquitocidal activity to Aedes aegypti. The 23 kDa Protein itself in vitro didn't show hemolytic activity on human erythrocytes, but the protein had the activity after proteinase K treatment.

• Animal Systematics, Evolution and Diversity
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• v.13 no.1
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• pp.29-36
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• 1997

한국산 기름종개속 어류중 Cobitis taenia complex의 집단간 유전적 차이에 따른 종 분화 여부를 밝히고자 6개 집단을 대상으로 mitochondrial DNA(mtDNA)의 RFLP분석을 실 시하였다. C. taenia complex mtDNA를 10개의 6-base cutting 제한효소로 처리한 다음 그 절편 양상을 비교, 분석한 결과 6개 집단 공히 mtDNA 의 전체 genome 크기는 약 17.0$\pm$ 0.5Kbp였으며 공동절편수(F)에서 C. t. taenia 2개집단과 C. t. stria와 C. t. lutheri 4개 집단 간의 F값은 평균 0.263으로 차이가 있었으나, C. t. striata 와 C. t. lutheri 사이는 F=0.569로 가깝게 나타났다. 염기치환율 (p)에 있어 C. t. taenia는 C. t. striata 및 C. t. lutheri와 평균 p=0.082로 뚜렷한 종간차이를 보였으나, C. t. striata와 C. t. lutheri 집단들은 p=0.033으로 매우 가까운 유사성을 나타내었다. MtDNA 분석결과 C. taenia complex 중 C. t. taenia는 완전히 종분화가 이루어진 별종으로, C. t. striata와 C. t. lutherisms 아직 종수준의 분화가 이루어지지 않은 아종으로 분류함이 타당하다고 사료된다.

• The Korean Journal of Zoology
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• v.22 no.4
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• pp.141-152
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• 1979

Feline leukemia virus DNA polymerase was purified by ion-exchange and nucleic acid affinity chromatographies. The enzyme consists of a single polypeptide chain of approximately 72, 000 molecular weight as determined by both of a glycerol density gradient centrifugation and SDS-polyacrylamide gel electrophoresis. The preferred divalent cation for DNA synthesis is $Mn^2+$ on a variety of template-primers, and its optimum concentration appears to be significantly lower than reported results of other mammalian type-C viral enzymes. The divalent cation requirement for maximum activity of RNase H is similar to those of DNA polymerase. Both DNA polymerase and RNase H activities appear to reside on the same molecule as demonstrated by the copurification of both activities through various purification steps. An additional RNase H without detectible polymerase activity was generated by a limited chymotrypsin digestion. This RNase H activity was inhibited equally effectively as RNase H in the intact reverse transcriptase by antisera prepared against reverse transcriptase of feline leukemia virus. Neutralization and binding test showed that antibody binding to reverse transcriptase molecule did not completely inhibit the polymerase activity.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.544-555
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• 2003

Since the result data from DNA microarray experiments contain a lot of gene expression information, adequate analysis methods are required. Hierarchical clustering is widely used for analysis of gene expression profiles. In this paper, we study leaf-ordering, which is a post-processing for the dendrograms output by hierarchical clusterings to improve the efficiency of DNA microarray data analysis. At first, we analyze existing leaf-ordering algorithms and then present new approaches for leaf-ordering. And we introduce a software HCLO(Hierarchical Clustering ＆ Leaf-Ordering Tool) that is our implementation of hierarchical clustering, some of existing leaf-ordering algorithms and those presented in this paper.

• Environmental Mutagens and Carcinogens
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• v.18 no.2
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• pp.71-76
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• 1998

Exposure to environmental toxicants can cause cellular problems including the interference of DNA repair processes which may lead to the development of cancer. The existence of toxicant-induced DNA repair abnormality was investigated using mice exposed in vivo to genotoxic chemicals and then challenging their exposed lymphocytes in vitro with bleomycin. The repair of bleomycin-induced DNA damage as estimated by the frequency of chromosome aberrations was determined. Our data indicates that the observed aberration frequencies after in vivo exposure to N-methyl-N'-nitro-N-nitnsoguanidine (MNNG) and in vitro challenge with bleomycin are consistently higher than expected. The enhanced response is not due to the induction of chromosome damage by 25 or 50 mg/kg MNNG since the chemical did not cause chromosome aberrations in lymphocytes of these mice. The observed response after the combined exposure to benzo[a]pyrene (BP) and bleomycin was significantly lower than expected with low in vivo doses of BP (50 mg/kg) and then significantly higher than expected with the high doses (200 mg/kg). We interpret our data to indicate that in vivo exposure to genotoxic agents can cause abnormal DNA repair activities. The response is, however, independent of the clastogenic activities of the inducing chemicals, but dependent upon the inducing agents and on the exposure doses.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.4
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• pp.371-377
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• 2016

Decalcification is routinely performed to obtain a pathological diagnosis using bone marrow biopsy. During the decalcification process using a conventional acidic solution, such as HCl, the antigenicity of tissue is damaged. Especially DNA and RNA in the bone marrow are impaired. Hence, there is the need for a standardized decalcification protocol that preserves the antigenicity of tissue. To this end, we compared the effects of two commonly used decalcifiers: Commercial decalcifier (Calcl-Clear Rapid, HCl) and the EDTA (12.5%, pH 7.0). Bone marrow biopsies sampled from 71 patients were decalcified in accordance with the protocols of respective groups-HCI versus EDTA. The differences of decalcification protocols were analyzed with respect to Hematoxylin & Eosin staining, Gomori'sreticulum staining, and immunohistochemical staining and molecular analysis. Immunohistochemical staining used Ki-67, CD20 and CD138 as primary antibodies and molecular analysis was conducted through the DNA concentration analysis, in situ hybridization (ISH) and immunoglobulin heavy chain (IGH) gene rearrangement. On the routine histopathology analysis, there was no difference between HCl and EDTA. Moreover, in case of immunohistochemical staining, the cytoplasmic membrane or cytoplasmic CD markers was well preserved. However, nuclear proteins, such as Ki-67, were stained with low quality. Conversely, according to the molecular analysis, the EDTA protocol preserved the DNA and RNA compared with the HCI. The differences of DNA quantity and quality were statistically significant between protocols of HCl and EDTA. We used 38 cases in HCl and 12 cases in EDTA. Consequently, the EDTA protocol maintains the antigenicity of the protein on tissue and is acceptable for examination with molecular base analysis. Decalcification of bone marrow biopsy by EDTA is highly recommended for the examination of immunohistochemical staining and molecular analysis.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.30-37
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• 1996

Background: The extraction methods of DNA from clinical samples are the major obstacle to use the PCR(polymerase Chain Reaction) in routine labortary for early detection of M. tuberculosis. We tried to improve the extraction method of DNA from sputum for establishment of the PCR in routine labortary by reducing the possibility of cross contamination and performing it easily and safely. Methods: We used the $InstaGene^{TM}$ DNA extraction kit(BioRad Co.) using Chelex 100 ion exchange resin for preparation of DNA. We compared InstaGene method in 100 cases of sputum from proteinase K method which is known as the most commonly used method for DNA purification(Experiment 1). And we compared InstaGene method in 98 cases of sputum from Microwave method developed by a company in Korea(Experiment 2). In experiment 1,245bps of IS6110 were amplified and then 188bps were amplified by nested PCR. In experiment 2,536bps in primary PCR and 276bps in nested PCR were amplified and analysed by agarose gel electrophoresis and EtBr staining. Results: When we chose AFB smear, culture, or AFB smear and culture as a standard test, PCR had low specificity and positive predictive value in both experiments. The InstaGene method has higher value in sensitivity and negative predictive value significantly than proteinase K method. The InstaGene method and the Microwave methods were similar in sensitivity, specificity, positive predictive value and negative predictive value. Conclusion: Even though both methods had lower possibility of cross contamination, shorter time requirement, simplicity, and economic advantages than Proteinase K method, the InstaGene method was a little simpler than the Microwave method. Therefore, in terms of usefulness in clinical application, the Instagene method seems to be the most useful method in DNA extraction for detection of M. tuberculosis using PCR. The reliability of this method will be clarified by further studies with enough clinical samples.