• The Journal of the Acoustical Society of Korea
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• v.26 no.1
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• pp.42-47
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• 2007

In this paper. we have studied improvement in sensitivity by increasing the frequency of SAW sensors for detecting the immobilization and hybridization of DNA. The sensor consists of twin SAW delay lines operating at 200MHz, a sensing channel and a reference channel. fabricated on $36^{\circ}$ rotated Y-cut X-propagation $LiTaO_3$ crystals. The optimum concentration of probe and target DNA was decided for the improvement of detection mechanism. and digital syringe pump system was used to reduce the human errors. The hybridization between immobilized probe DNA and target DNA on the gold-coated delay line results in mass loading on the delay line of the sensing channel. Thus, the relative frequency change was monitored in relation to the mass loading. The measurement results showed a good response of the sensor to the DNA hybridization with a maximum sensitivity level up to 0.066ng/m1/Hz.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.2
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• pp.86-90
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• 2011

The effects of cations are very important in field-effect transistors (FETs) type DNA sensors detecting the intrinsic negative charge between single-stranded DNA and double-stranded DNA without labeling, because the intrinsic negative charge of DNA is neutralized by cations in electrolyte solution. We consider the Debye length, which depends on the concentration of cations in solution, to detect DNA hybridization based on the intrinsic negative charge of DNA. The Debye length is longer in buffer solution with a lower concentration of NaCl and the intrinsic negative charge of DNA is more effective on the channel surface in longer Debye length solution. The shifts in the gate voltage by DNA hybridization with complementary target DNA are 21 mV in 1 mM NaCl buffer solution, 7.2 mV in 10 mM NaCl buffer solution, and 5.1 mV in 100 mM NaCl buffer solution. The sensitivity of FETs to detect DNA hybridization based on charge detection without labeling depends on the Debye length.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.59-59
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• 1993

비방사능물질인 Biotin을 DNA probe에 표지하여 nonisotopic hybridization 방법을 사용하여 감도를 높임으로써, 손쉽게 생물공학 의약품의 품질관리에 사용되도록 하였다. Bethesda Research Laboratories(BRL) 회사 제품인 biotinylated probes-avidin alkaline phosphatase를 이용한 chemiluminescene detection방법으로 행하여 λ phage DNA, yeast DNA, E.coil DNA의 한계 검출 농도를 알아내고, 생물 공학 제품에 적용하였다. Dot blot hybridization 방법으로 행하여 λ phage DNA는 0.1pg, Yeast DHA는 4.5pg, E. coli DNA는 8.9pg까지 검출되었고, 기존 생물공학 제품에서는 숙주 유래 DNA가 전혀 검출되지 않았다.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.387-394
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• 1994

To make the genomic DNA probe of Theileria sergenti, the merozoites were purified from bovine erythrocytes. The infected erythrocytes were lysed by Aeromonas hydrophila(Ah-1) hemolysin, and the parasites were isolated by ultracentrifugation on a Percoll discontinuous density gradient. For construction of a T sergenti genomic DNA library, T sergenti DNA was digested with Pstl and the fragments were ligated into the PstI site of pUC19 before transformation of Escherichia coli JM83. Out of thousands of transformants obtained by transformation of E coli JM83 with the genomic library, three plasmids were chosen. The sizes of the inserted DNAs were 2.9kb(2.4kb and 0.5kb) in pKTS1, 4.3kb in pKTS2 and 1.5kb in pKTS3, respectively. The DNA fragments used as probe KTS1(2.4kb), KTS2(4.3kb) and KTS3(1.5kb) were labeled digoxigenin-11-dUTP for the Southern hybridization. In Southern hybridization, all of the probes(KTS1, KTS2 and KTS3) reacted specifically to T sergenti DNA, but not to bovine leucocyte DNA. In order to find out the sensitivities of the digoxigenin-11-dUTP-labeled KTS1 and KTS3 as the probes, purified merozoite DNA and bovine DNA (control) were checked by dot blot hybridization with the probes. Both of the probes, KTS1 and KTS3, detected as minimum amount of 975pg of the T sergenti DNA, but not bovine DNA even to 500ng.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.470-474
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• 2003

DNA sequence information on small-subunit rRNA gene (16S rDNA) obtained from food-poisoning bacterial culture was used to investigate the presence of bacterial pathogens in food. By reverse dot blot detection method, presence of food-poisoning bacteria could be confirmed on hybridization of digoxigenin-labeled 16S rDNA Polymerase Chain Reaction (PCR) primer product and biotin-labeled specific oligonucleotide probe. Escherichia coli, Bacillus cereus. and Salmonella sp. were used as the representative food-poisoning bacterial microorganisms. An oligonucleotide probe, based on the variable region of 16S rRNA gene, was used as the specific probe. These tools may be more useful than classic biochemical method for rapid identification of contaminated food.

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

• Journal of Plant Biology
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• v.38 no.2
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• pp.203-209
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• 1995

Tobacco (Nicotiana tahacum L. cv. Wisconsin 38) leaf discs were cocultivated with Agrohacterium carrying a leghemoglobin (Lb) cDNA from Canavalia lineata. Seven plants were regenerated from the transformed leaf discs on MS media supplemented with 0.5 mg/L BAP, 0.1 mg/L ${\alpha}-NAA$, 200 mg/L kanamycin and 500 mg/L carbenicillin. Southern hybridization and PCR of genomic DNA from transgenic plants showed that the Lb cDNA was stably integrated into the genome of the tobacco. Total RNA from the transgenic tobacco showed northern hybridization signal at 1,000 nt and PCR of the first strand cDNA synthesized from the total RNA amplified 0.5 kb Lb cDNA. Furthermore, western hybridization using a polyclonal antibody against soybean Lb showed a 15.8 kD LB-like band on SDS-PAGE of proteins from the transformed tobacco. These results demonstrated that the Lb cDNA of C. lineata was not only incorporated into the genome of tobacco, but also transcribed into mRNA and translated into Lb protein in the transformed tabacco.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.772-774
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• 2003

DNA/DNA의 연쇄 결합 반응에 대한 시뮬레이션을 열역학적 데이터를 이용하여 구현하였다. 1-Base의 non Watson-Crick 결합과, dangling end(결합이 이루어진 두개의 DNA strand 중 한쪽 끝이 다른 쪽 끝보다 길거나 짧은 경우)를 허용하는 nearest-neighbor model을 사용하여 구현된 이 모델에서는 한번의 hybridization만을 예측하는 것이 아니라 연속적인 결합 반응의 시뮬레이션이 가능하다. 이를 통해서 분자 알고리즘의 설계와 검증이 가능할 뿐만 아니라, cross-homology의 검사를 통한 시퀀스의 검증까지도 가능하다. 이러한 in silico 에서의 접근 방식은 효율적인 분자 알고리즘의 개발과 신뢰성 있는 시퀀스의 설계에 도움이 될 수 있다.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.114-117
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• 2003

In molecular biology, it is necessary to develop an easy and rapid method to identify a specific DNA sequence. Though Southern and Northern blot techniques have been used widely for the analysis of gene structure and function, those methods are inconvenient in the points that we need to control incubation temperature, time, and other parameters to get the final result. In this study, we report a new method for the rapid analysis of specific DNA sequence with the modification of an immunochromatographic method. The lateral flow DNA analysis strip is composed of a sample pad, a nitrocellulose membrane for the separation and propagation of analytes, and an absorption pad for the generation of capillary action. Capture DNA was immobilized on the membrane by UV cross-linking and target DNA was labeled with Cy-5 for signaling. The samples containing target DNA were applied onto the sample pad, incubated for 15 min for separation, and scanned with a GSI fluorescence scanner. Though the hybridization reaction occurs in a short time without any washing steps, there appears to be little cross hybridization between the different sequences. The result showed a possibility that the new method can be used for the rapid identification of specific DNA sequence among the samples.

• Korean journal of applied entomology
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• v.29 no.2
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• pp.132-135
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• 1990

Three mitochondrial cDNA probes from Aedes albopictus were used to demonstrate restriction site polymorphism in mtDNA of three sibling species of Anopheles quadrimaculatus(Say). It was shown by DNA hybridization to have substantial sequence homology betwen the mtDNA of different genus. The proves reveled local restriction site variation between members of the Anopheles quadrimaculatus sibling species complex. Mitochondrical DNA (mtDNA), isolated from individual mosquitoes was digested by type II restriction enzymes and four enzymes were found to be useful for the purpose. Hind III alone could be used to obtain a diagnostic restriction pattern.