• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.7
• /
• pp.729-737
• /
• 2004

In this paper, a DNA chip with a microelectrode array was fabricated using microfabrication technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5 end were immobilized on the gold electrodes by DNA arrayer. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.845-848
• /
• 2004

High throughput analysis using a DNA chip microarray is powerful tool in the post genome era. Less labor-intensive and lower cost-performance is required. Thus, this paper aims to develop the multi-channel type label-free DNA chip and detect SNP (Single nucleotide polymorphisms). At first, we fabricated a high integrated type DNA chip array by lithography technology. Various probe DNAs were immobilized on the microelectrode array. We succeeded to discriminate of DNA hybridization between target DNA and mismatched DNA on microarray after immobilization of a various probe DNA and hybridization of label-free target DNA on the electrodes simultaneously. This method is based on redox of an electrochemical ligand.

• The Korean Journal of Zoology
• /
• v.32 no.4
• /
• pp.305-313
• /
• 1989

The present investigation aims at inquiring into a possible target for the heat inactivation of SCK tumor cells by comparing the kinetics of cell survival, rate of protein synthesis, and DNA polymerase activity in the presence of heat protector or heat sensitirer. A possible conclusion to be drawn from the present experiment is that there is no direct correlation between cell death and decrease in the rate of protein synthesis, but that the loss of DNA polvmerase $\beta$ activity correlates quite well with cell inactivation. Thus, protein degrada-tion and/or abnormal protein synthesis causes cell inactivation innireuv, possibly by altering the cellular environment which in turn affects the DNA polymerase $\beta$ activity. Accordingly, further studies, dealing with the correlation between changes in the cellular environment and DNA polymerase $\beta$ activity, are needed to set insight into a possible target for the heat inactivation of cells. 본 연구는 열보호제 또는 열증감제의 존재하에서 세포 생존곡선, 단백질 합성률, DNA 중합효소 $\beta$의 활성변화를 비교 검토함으로써 SCK 종양세포가 열에 의해서 불활성화될 때의 표적이 무엇인지를 밝혀보기 위해서 수행되었다. 본 실험의 결과로 추정하건대 열에 의한 세포치사는 단백질 합성률의 변화와는 직접적인 연관성이 없으나, DNA 중합효소 $\beta$의 활성도와는 밀접한 연관성이 있음을 알 수 있다. 즉, 단백질의 분해 또는 비정상적인 단백질의 합성이 세포의 환경을 변화시키고 이것이 DNA 중합효소 $\beta$의 활성에 영향을 미침으로써 간접적으로 세포의 치사를 초래할 것으로 짐작할 수 있다. 따라서, 세포의 열불화성화의 표적을 좀더 분명히 밝히기 위해서는 세포의 환경변화와 DNA 중합효소 $\beta$의 활성과의 관계를 추구하는 연구가 수행되어야 할 것으로 사료된다.

• Korean Journal of Microbiology
• /
• v.41 no.4
• /
• pp.239-245
• /
• 2005

Transformation-Associated Recombination (TAR) cloning technique allows selective isolation of chromosomal regions and genes from complex genomes. The procedure requires knowledge of relatively small genomic sequences that reside adjacent to the chromosomal region of interest. This technique involves homologous recombination during yeast spheroplast transformation between genomic DNA and a TAR vector that has 5' and 3' gene targeting sequences. In this study, we examined the effect of non-homologous spacing sequence in target hooks on homologous recombination using a plasmid model system. The efficiency of homologous recombination between the modified his3-TRP1-his3 fragments and HlS3 gene on plasmid were analyzed by the characterization of $Ura^+$ transformants. The numbers of $Ura^+$ transformant showed same level when seven different modified his3-TRP1-his3 fragments were used. But the percentage of positive recombinants. $Trp^+His^-$, dramatically decreased when used the modified his3-TRP1-his3 fragments contained incorrect spacing of nonhomologous region. As a result, we suggest that incorrect spacing inhibits the homologous recombination between target hook and substrate DNA. Therefore, we should consider the correct spacing in target hook when the target hook are used for cloning of orthologue gene.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.4
• /
• pp.145-148
• /
• 2004

In this study, a DNA chip with a microelectrode array was fabricated using microfabrication technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5' end were immobilized on the gold electrodes by a DNA arrayer. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 and concentrated at the electrode surface through association with the formed hybrid. This suggested that this DNA chip could recognize the sequence specific genes.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2125-2127
• /
• 2004

In this paper, a DNA chip with a microelectrode array was fabricated using microfabrication technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5 end were immobilized on the gold electrodes by DNA arrayer. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2128-2130
• /
• 2004

High throughput analysis using a DNA chip microarray is powerful tool in the post genome era. Less labor-intensive and lower cost-performance is required. Thus, this paper aims to develop the multi-channel type label-free DNA chip and detect SNP (Single nucleotide polymorphisms). At first, we fabricated a high integrated type DNA chip array by lithography technology. Various probe DNAs were immobilized on the microelectrode array. We succeeded to discriminate of DNA hybridization between target DNA and mismatched DNA on microarray after immobilization of a various probe DNA and hybridization of label-free target DNA on the electrodes simultaneously. This method is based on redox of an electrochemical ligand.

• Proceedings of the KIEE Conference
• /
• 2006.07c
• /
• pp.1324-1326
• /
• 2006

In this study, an integrated microelectrode array was fabricated on glass slide using microfabrication technology. Probe DNAs consisting of mercaptohexyl moiety at their 5-end were spotted on the gold electrode using micropipette or DNA arrayer utilizing the affinity between gold and sulfur. Cyclic voltammetry in 5mM ferricyanide/ferrocyanide solution at 100 mV/s confirmed the immobilization of probe DNA on the gold electrodes. When several DNAs were detected electrochemically, there was a difference between target DNA and control DNA in the anodic peak current values. It was derived from specific binding of Hoechst 33258 to the double stranded DNA due to hybridization of target DNA. It suggested that this DNA chip could recognize the sequence specific genes. It suggested that multichannel electrochemical DNA microarray is useful to develop a portable device for clinical gene diagnostic system.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1997.04a
• /
• pp.40-47
• /
• 1997

New quinolones generally have a broad antibacterial spectrum against gram-positive, gram-negative, glucose-nonfermenting and anaerobic bacteria. Some of newly developed quinolones have potent activities against S. aureus including MRSA, S.pneumoniae including PRSP, B. fragilis, chlamydiae, mycoplasmas and mycobacteria as well, and show good activities against various strains resistant to antibacterial agents of other classes. Quinolones display postantibiotic effects in vitro and are bactericidal at concentrations similar to or twice that of the minimum inhibitory concentrations (MICs) for susceptible pathogens. In experimental murine infection models including systemic infections with various pathogens such as S. aureus, S. pyogenes, S. pneumoniae, E. coli and P. aeruginosa, quinolones have shown good oral efficacy as well as parenteral efficacy. Good oral absorption and good tissue penetration of quinolones account for good therapeutic effects in clinical settings. The target of quinolones are two structurally related type II topoisomerases, DNA gyrase and DNA topoisomerase IV. Quinolones are shown to stabilize the ternary quinolone-gyrase-DNA complex and inhibit the religation of the cleaved double-stranded DNA. Bacteria can acquire resistance to quinolones by mutations of these target enzymes. Mutation sites and amino acid changes in DNA gyrase and DNA topoisomerase IV are similar in the organisms examined, suggesting that the mechanism of quinolone resistance in the target enzymes is essentially the same among various organisms. Quinolones act on both the target enzymes to different degrees depending on the organisms or agents tested, and bacteria become highly resistant to quinolones in a step-wise fashion. Incomplete cross-resistance among quinolones in some strains of E. coli and S. aureus suggests the possibility of finding quinolones active against quinolone-resistant strains which are prevailing now. To find such quinolones, the potency toward two target enzymes and the membrane permeability including influx and/or efflux systems should be taken into account.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.82-85
• /
• 2005

Doxorubicin is a highly-valuable anthracycline-family polyketide drug with a very potent anticancer activity, typically produced by a Gram-positive soil bacterium called Streptomyces peucetius. Thanks to the recent development of Streptomyces genomics-based technologies, the random mutagenesis approach for Streptomyces strain improvement has been switched toward the genomics-based technologies including the application of DNA microarray systems. In order to identify and characterize the genomics-driven potential target genes critical for doxorubincin overproduction, three different types of doxorubicin overproducing strains, a dnrI(doxorubicin-specific positive regulatory gene)-overexpressor, a doxA (gene involved in the conversion from daunorubicin to doxorubicin)-overexpressor, and a recursively-mutated industrial strain, were generated and examined their genomic transcription profiles using Streptomyces DNA microarray systems. The DNA microarray results revealed several potential target genes in S. peucetius genome, whose expressions were significantly either up- or down-regulated comparing with the wild-type strain. A systematic understanding of doxorubicin overproduction at the genomic level presented in this research should lead us a rational design of molecular genetic strain improvement strategy.