• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.86-93
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• 2000

Paratuberculosis (Johne's disease), a chronic enteritis produced by Mycobacterium paratuberculosis, affects a large proportion of ruminants in all continents and causes important economic losses. The identification of well-characterized and species-specific components of M paratuberculosis would provide the means to improve the specificity and sensitivity of immunodiagnostic assays for Johne's disease. The aims of this study were to express the recombinant C-terminal of 34kDa protein (rC34P) of M paratuberculosis in E coli and to investigate the effectiveness of this protein in detecting antibodies to the native protein in sera from paratuberculosis infected cattle. The C-terminal of the gene encoding the 34kDa protein was amplified by polymerase chain reaction from the chromosomal DNA of M paratuberculosis (ATCC 19698) and cloned into vector pGEX-4T-2. Then, cloned plasmid was transformed into E coli DH5${\alpha}$ and the rC34P was overexpressed. The rC34P was purified by affinity chromatography and gel filtration. The rC34P was examined antigenicity by Western blot. The rC34P was reactive with culture positive bovine serum and hyperimmune rabbit anti-M paratuberculosis serum but was not reactive with culture negative bovine serum and tuberculin positive bovine serum in Western blot. In conclusion, the rC34P produced in this study is expected as a useful candidate for antigen in serological diagnosis of Johne's disease.

• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.273-280
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• 2008

Mycobacterium tuberculosis (MTB) remains a major worldwide public health problem. In recent years, the incidence of MTB has been rising. Rapid and reliable diagnosis of Mycobacterium tuberculosis is essential to initiate correct treatment, avoid severe complications, and prevent transmission. LAMP was used to develop a rapid and sensitive laboratory diagnostic system for the MTB. In this research, the loop-mediated isothermal amplification method (LAMP) that amplifies DNA with high specificity and rapidity at an isothermal condition was evaluated for rapid detection of MTB. Undiluted DNA (2.10 × 106 copy/mL), 10-1, 10-2, 10-3, 10-4, 10-5 and 10-6 (copy/mL) of MTB DNA were amplified by PCR and LAMP to determine the sensitivity of the assay. At results, the LAMP assay reported here has the advantages of rapid amplification, high sensitivity, and high specificity and will be useful for rapid and reliable clinical diagnosis of MTB in hospital clinical laboratory.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.142-152
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• 2005

Background : Priming and boosting vaccination strategy has been widely explored for new vaccine development against tuberculosis. As an effort to identify other vaccine candidates, this study was initiated to evaluate protective efficacy of adenylate kinase (AK), nucleoside diphosphate kinase (NdK), and heat shock protein 70 (Hsp70) of Mycobacterium tuberculosis. Method : M. tuberculosis genes encoding AK, NdK, and Hsp70 proteins were amplified by PCR and cloned into E. coli expression vector, pQE30. Recombinant AK, NdK, and Hsp70 was purified through Ni-NTA resin. To evaluate immune responses, we performed enzyme-linked immunosorbent assay (ELISA) for IgG isotype and $IFN-{\gamma}$ after mice were immunized subcutaneously with recombinant proteins delivered in dimethyl dioctadecylammonium bromide (DDA). Immunized- and control groups were challenged by aerosol with M. tuberculosis. The spleens and lungs of mice were removed aseptically and cultured for CFU of M. tuberculosis. Result : Vaccination with recombinant proteins AK, NdK, and Hsp70 delivered in DDA elicited significant level of antibody and $IFN-{\gamma}$ responses to corresponding antigens but no protective immunity comparable to that achieved with Mycobacterium bovis BCG. Conclusion : Recombinant proteins AK, NdK, and Hsp70 do not effectively control growth of M. tuberculosis in mice when immunized with DDA as an adjuvant.

• The Journal of the Korean Society for Microbiology
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• v.34 no.6
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• pp.561-571
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• 1999

Diagnosis of mycobacterial infection is dependent upon the isolation and identification of causative agents. The procedures involved are time consuming and technically demanding. To improve the laborious identification process mycobacterial systematics supported by gene analysis is feasible, being particularly useful for slowly growing or uncultivable mycobacteria. To complement genetic analysis for the differentiation and identification of mycobacterial species, an alternative marker gene, rpoB encoding the ${\beta}$ subunit of RNA polymerase, was investigated. rpoB DNAs (342 bp) were amplified from 52 reference strains of mycobacteria including Mycobacterium tuberculosis H37Rv (ATCC 27294) and clinical isolates by the PCR. The nucleotide sequences were directly determined (306 bp) and aligned using the multiple alignment algorithm in the MegAlign package (DNASTAR) and MEGA program. A phylogenetic tree was constructed with a neighborhood joining method. Comparative sequence analysis of rpoB DNA provided the basis for species differentiation. By being grouped into species-specific clusters with low sequence divergence among strains belonging to same species, all the clinical isolates could be easily identified. Furthermore RFLP analysis enabled rapid identification of clinical isolates.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.94-105
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• 2001

Background : Examining the biological susceptibility of Mycobacterium tuberculosis to pyrazinamide (PZA) in vitro is very difficult as PZA is inactive under normal culture conditions. The biological susceptibility test, an enzyme assay for Pzase activity, and a genetic test for pncA gene mutations, were performed in order to predict PZA resistance. Methods : 28 cultured clinical isolates of Mycobacterium tuberculosis were tested. The biological susceptibility was performed by the absolute concentration method using Lowenstein-Jensen media. The PZase activity was tested by means of Wayne's method. A 710-bp region includes the entire open reading frame of pncA was amplified and sequenced. Results : All six strains with positive PZase activity exhibited no pncA mutations with one strain showing a false resistance in the biological susceptibility test. Among the 22 strains with no PZase activity, 21 exhibited showed pncA mutations. In the biological susceptibility test, 20 strains were resistant, and one was susceptible, and the other flied to test. The mutation types varied with ten missense, one silent and one nonsense mutation 1 slipped-strand mispairing, and 6 frameshift mutations. Three strains had an adenine to guanine mutation at position -11 upstream of the start codon. Conclusion : The mutation at the pncA promotor region is frequent at -11 upstream position. Automatic sequencing of pncA is a useful tool for rapid and accurate detection of PZA resistant M. tuberculosis, and for demonstrating the epidemiological relatedness of the PZA resistant M. tuberculosis strains.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.8-13
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• 1996

Background: The 463 codon mutation of katG gene has been reported as an useful marker for the detection of isoniazid(INH) resistant strains of M. tuberculosis. This study aimed to elucidate relationship between 463 mutation in katG gene and INH resistance in M. tuberculosis. Method: DNA was extracted from 28 INH susceptible strains(MIC$\geq\;0.2{\mu}g/ml$ on the L$\ddot{o}$wenstein Jensen media) and used for amplification of 189bp fragment containing 463 codon by PCR. Amplified fragments were digested by restriction enzyme Msp I, analyzed by single strand conformation polymorphism(SSCP) in the MDE gel and sequenced to prove mutation. Result: Only 7(25%) out of 28 were digestible by restriction enzyme Msp I. The SSCP pattern of 21 strains were distinctly different from that of M. tuberculosis H37Rv. Msp I undigestible PCR fragment was substituted at 463 codon from Arg(CGG) to Leu(CTG). Conclusion: This finding clearly indicate no relationship between 463 codon mutation of the katG gene and INH resistance.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1830-1836
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• 2003

Studies using natural resistance-associated macrophage protein (NRAMP) identification indicated that cattle could be selected for immunity. Several studies performed on intracellular organisms such as Mycobacterium, Salmonella, Brucella and Leishmania in human and mouse revealed that resistance against these bacteria was dependent on high activity of NRAMP1 in macrophages. However, hardly any researches have been done on Staphylococcus aureus in bovine mastitis, which is an intracellular organism and the main cause of bovine mastitis. The objectives of this study were to establish reverse transcriptase polymerase chain reaction (RT-PCR) methods, through which NRAMP1 mRNA expression could be compared and analyzed between mastitis-resistant and -susceptible cows. NRAMP1 gene and its expression were investigated using 20 cows (Holstein Friesian) in Korea. Cows were evenly split into two groups, with and without histories of clinical mastitis. Equivalent numbers of cows were randomly selected from each group. Monocytes were isolated from the bovine peripheral blood of each selected cows and activated with lipopolysaccharide (LPS). mRNA was separated from the monocytes and cDNA of NRAMP1 was synthesized and amplified using RT-PCR with amplification of $\beta$-actin as a control. The difference in NRAMP1 expressions of mastitis-resistant (n=10) and -susceptible (n=10) Holstein cows was analyzed. Results demonstrate that resistant cows produced more NRAMP1 mRNA than the susceptible ones, and ratios of NRAMP1:$\beta$-actin expression were higher in resistant cows with or without LPS activation. Therefore, this study could be applied to select bovine mastitis resistant cows before infection based on the expression of NRAMP1.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.546-557
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• 2000

Background : Oligonucleotide chip technology has proven to be a very useful tool in the rapid diagnosis of infectious disease. Rifampin resistance is considered as a useful marker of multidrug-resistance in tuberculosis. Mutations in the rpoB gene coding $\beta$ subunit of RNA polymerase represent the main mechanism of rifampin resistance. The purpose of this study was to develop a diagnosis kit using oligonucleotide chip for the rapid and accurate detection of rifampin-resistance in Mycobacterium tuberculosis. Method : The sequence specific probes for mutations in the rpoB gene were designed and spotted onto the glass slide, oligonucleotide chip. 38 clinical isolates of Mycobacterium were tested. A part of rpoB was amplified, labelled, and hybridized on the oligonucleotide chip with probes. Results were analyzed with a laser scanner. Direct sequencing was done to verify the results. Result : The low-density oligonucleotide chip design어 to determine the specific mutations in the rpoB gene of M. tuberculosis accurately detected rifampin resistance associated with mutations in 28 clinical isolates. Mutations at codons 531, 526, and 513 were confirmed by direct sequencing analysis. Conclusion : Mutant detection using oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of multidrug-resistance in M. tuberculosis.

• 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.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.129-134
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• 2005

Background : Ethambutol (EMB) is one of important first-line drug in the treatment of tuberculosis. Molecular techniques to detect embB gene mutations have been considered as an method to define the EMB resistance. We investigated the mutation rate within embB gene among EMB resistant strains using reverse hybridization techniques. Methods : We made 11 probes that had wild or mutated sequences containing codons 306, 406, or 497 within embB gene respectively. These probes were reverse-hybridized with PCR products amplified from embB gene which were isolated from 149 ethambutol resistant strains and 50 pan-susceptible strains. Results : Out of 149 ethambutol resistant strains, one hundred (67.1%) had mutation at least one base at codon 306, 406, or 497 in embB gene. Mutation at codon 306, 406, 497 were demonstrated in 75 (50.3%), 16 (10.7%), and 13 strains (8.7%) respectively. There were four strains that showed multi-mutation at codon 306 and codon 406 simultaneously. A high proportion (8.1%) had single mutation at codon 406. There was no mutation observed in embB gene among 50 pan-susceptible strains. Conclusion : Reverse hybridization will be useful technique for detection of gene mutation correlated to ethambutol resistance.