• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.745-752
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• 2015

Tuberculosis (TB) is the most common mycobacterial infection in developing countries, requiring a rapid, accurate, and well-differentiated detection/diagnosis. For the rapid detection and discrimination of Mycobacterium tuberculosis complex (MTC) from non-tuberculous mycobacteria (NTM), a novel, simple, and primer-combined single-step multiplex PCR using three primer pairs (6110F-6110R, 1081F-1081R, and 23SF-23SR; annealing on each of IS6110, IS1081, and 23S rDNA targets), hereafter referred to as a triplex PCR, has been developed and evaluated. The expected product for IS6110 is 416 bp, for IS1081 is 300 bp, and for 23S rDNA is 206 bp by single PCR, which was used to verify the specificity of primers and the identity of MTC using DNA extracted from the M. tuberculosis H37Rv reference strain (ATCC, USA) and other mycobacteria other than tuberculosis (MOTT) templates. The triplex PCR assay showed 100% specificity and 96% sensitivity; the limit of detection for mycobacteria was ~100 fg; and it failed to amplify any target from DNA of MOTT (50 samples tested). Of 307 blinded clinical samples, overall 205 positive M. tuberculosis samples were detected by single PCR, 142 by conventional culture, and 90 by AFB smear methods. Remarkably, the triplex PCR could subsequently detect 55 positive M. tuberculosis from 165 culture-negative and 115 from 217 AFB smear-negative samples. The triplex PCR, targeting three regions in the M. tuberculosis genome, has proved to be an efficient tool for increasing positive detection/discrimination of this bacterium from clinical samples.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.87-99
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• 2022

A novel porcine circovirus 4 (PCV4) was recently emerged in Chinese and Korean pig herds, which provided epidemiological situation where three pathogenic PCVs, PCV2, PCV3, and newly emerged PCV4, could co-infect pig herds in these countries. In this study, a new triplex quantitative real-time polymerase chain reaction (tqPCR) method was developed for the rapid and differential detection of these viruses. The assay specifically amplified each viral capsid gene, whereas no other porcine pathogenic genes were detected. The detection limit of the assay was below 10 copies/µL and the assay showed high repeatability and reproducibility. In the clinical evaluation using 1476 clinical samples from 198 Korean pig farms, the detection rates of PCV2, PCV3 and PCV4 by the tqPCR assay were 13.8%, 25.4%, and 3.8%, respectively, which were 100% agreement with those of previously reported monoplex qPCR assays for PCV2, PCV3, and PCV4, with a κ value (95% CI) of 1 (1.00~1.00). The prevalence of PCV2, PCV3, and PCV4 at the farm levels were 46.5%, 63.6%, and 19.7%, respectively. The co-infection analysis for tested pig farms showed that single infection rates for PCV2, PCV3, and PCV4 were 28.8%, 44.4%, and 9.6%, respectively, the dual infection rates of PCV2 and PCV3, PCV2 and PCV4, and PCV3 and PCV4 were 12.6%, 3.5%, and 5.1%, respectively, and the triple infection rate for PCV2, PCV3, and PCV4 was 1.5%. These results demonstrate that three pathogenic PCVs are widely spread, and their co-infections are common in Korean pig herds, and the newly developed tqPCR assay will be useful for etiological and epidemiological studies of these pathogenic PCVs.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.305-316
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• 2022

Bordetella (B.) bronchiseptica, Mycoplasma (M.) felis, and Chlamydia (C.) felis are considered as main bacterial pathogens of feline upper respiratory tract disease (URTD). In this study, a new triplex quantitative real-time polymerase chain reaction (tqPCR) assay was developed for the rapid and differential detection of these bacteria in a single reaction. The assay specifically amplified three bacterial genes with the detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with coefficients of intra-assay and inter-assay variation of less than 1%. Based on the diagnostic results of the assay using 94 clinical samples obtained from cats with URTD signs, prevalence of B. bronchiseptica, M. felis, or C. felis was 10.6%, 36.2%, or 6.4%, respectively, indicating that the diagnostic sensitivity was comparable to those of previously reported monoplex qPCR assays. The dual infection rates for B. bronchiseptica and M. felis or M. felis and C. felis was 2.1% or 3.2%, respectively. These results indicated that M. felis has been widely spread, and its co-infection with B. bronchiseptica or M. felis has been frequently occurred in Korean cat population. The developed tqPCR assay will serve as a promising tool for etiological and epidemiological studies of these three bacterial pathogens and the prevalence data obtained in this study will contribute to expanding knowledge about the epidemiology of feline URTD in Korea.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.1
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• pp.17-26
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• 2005

Objective: Preimplantation genetic diagnosis (PGD) is reserved for couples with a risk of transmitting a serious and incurable disease, and hence avoids the undesirable therapeutic abortion. In this study, we evaluated the efficacy of PGD for Duchenne muscular dystrophy (DMD) cases by the fluorescent PCR with polymorphic linked markers and the conventional duplex-nested PCR methods. Methods: Biopsy of one or two blastomeres was done from the embryos fertilized by ICSI on the third day after fertilization. We performed two cases of PGD-DMD by the duplex-nested PCR for the causative mutation loci and the SRY gene on Y chromosome. The triplex fluorescent PCR for the mutation loci, the SRY gene and the polymorphic microsatellite marker on X chromosome was applied for two cases of PGD-DMD. Results: By the duplex-nested PCR, successful diagnosis rate was 95.5% (21/22), but we could not discriminate the female embryos whether normal or carrier in this X-linked recessive disease. However, the triplex fluorescent PCR method showed 100% (27/27) of successful diagnosis rate, and all female embryos (n=17) were distinguished normal (n=10) from carrier (n=7) embryos. Unaffected and normal embryos were transferred into mother's uterus after diagnosis. A healthy normal male was achieved after PGD with the duplex-nested PCR method and a twin, a male and a female, were delivered with triplex fluorescent PCR method. The normality of dystrophin gene was confirmed by amniocentesis and postnatal genetic analysis in all offsprings. Conclusion: The fluorescent PCR with polymorphic marker might be useful in improving the specificity and reliability of PGD for single gene disorders.

• Korean Journal of Veterinary Service
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• v.46 no.1
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• pp.15-27
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• 2023

Bordetella (B.) bronchiseptica, Mycoplasma (M.) cynos, and M. canis are the major bacterial pathogens that cause canine infectious respiratory disease complex (CIRDC). In this study, we developed a triplex real-time polymerase chain reaction (tqPCR) assay for the differential detection of these bacteria in a single reaction. The assay specifically amplified three bacterial genes with a detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with coefficients of intra- and inter-assay variations of less than 1%. The diagnostic results of the assay using 94 clinical samples from household dogs with CIRDC clinical signs, the prevalence of B. bronchiseptica, M. cynos, and M. canis was 22.3%, 18.1%, and 20.2%, respectively, indicating that the diagnostic sensitivity was comparable to those of previously reported qPCR assays. The dual infection rate of B. bronchiseptica and M. cynos, B. bronchiseptica and M. canis, and M. cynos and M. canis was 5.3%, 7.4%, and 3.1%, respectively. Moreover, the triple infection rate of B. bronchiseptica, M. cynos, and M. canis was 2.1%. These results indicate that coinfections with B. bronchiseptica, M. cynos, and M. canis have frequently occurred in the Korean dog population. The newly developed tqPCR assay in the present study will be a useful tool for etiological and epidemiological studies on these three CIRDC-associated bacterial pathogens. The prevalence and coinfection data revealed through this study will contribute to expanding knowledge on the epidemiology of CIRDC in the recent Korean dog population.

• Korean Journal of Veterinary Service
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• v.46 no.4
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• pp.269-281
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• 2023

In this study, a new triplex real-time quantitative reverse transcription polymerase chain reaction (tqRT-PCR) assay was developed for the rapid and differential detection of three feline viral pathogens including feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), and influenza A virus (IAV) in a single reaction. The assay specifically amplified three targeted viral genes with a detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with intra- and inter-assay coefficients of variation of less than 1%. Based on the diagnostic results of the assay using 120 clinical samples obtained from cats with feline respiratory disease complex (FRDC)-suspected signs, the prevalence of FCV, FHV-1, or IAV was 43.3%, 22.5%, or 0%, respectively, indicating that the diagnostic sensitivity was comparable or superior to those of previously reported monoplex qRT-PCR/qPCR assays. The dual infection rate for FCV and FHV-1 was 8.3%. These results indicate that FCV and FHV-1 are widespread and that co-infection with FCV and FHV-1 frequently occur in the Korean cat population. The developed tqRT-PCR assay will serve as a promising tool for etiological and epidemiological studies of these three bacterial pathogens, and the prevalence data for three feline viruses obtained in this study will contribute to expanding knowledge about the epidemiology of FRDC in the current Korean cat population.

• Toxicological Research
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• v.20 no.2
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• pp.101-108
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• 2004

The different social reflections about the benefits and the potential risks of genetically modified (GM) crops have evolved with .different reactions in different countries. Many countries including Korea are working toward setting down new guidelines. Korea requires companies to label all food that contains more than 3% GM ingredients. One of the rapid and convenient detection methods of GM ingredients is amplification of the introduced DNAs by polymerase chain reaction (PCR). Many PCR kits for this purpose are commercially available. The objective of this study was to evaluate performance of commercialized GM crop detection kits. The results showed that 6 out of 15 kits tested did not meet the requirements even purposed by the manufacturers themselves in terms of stability, reproducibility, and detection limits, suggesting a potential quality control problem in their design stage or production line. The evaluation also suggests that, although the duplex and triplex detection kits allowed unambiguous detection in a single PCR reaction, the monoplex detection kits were the most sensitive to the detection of GM ingredients. The detection limits also differ between soybean and corn. Results from this study will be useful in the development of sound qualitative tracking systems of GM ingredients for monitoring throughout the cultivation of GM crops, their trans-boundary movement, and food production using GM grains as well as for complying with government guidelines associated with GM crops.

• Clinical and Experimental Reproductive Medicine
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• v.40 no.4
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• pp.163-168
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• 2013

Objective: Preimplantation genetic diagnosis (PGD) is an assisted reproductive technique for couples carrying genetic risks. Charcot-Marie-Tooth (CMT) disease is the most common hereditary neuropathy, with a prevalence rate of 1/2,500. In this study, we report on our experience with PGD cycles performed for CMT types 1A and 2F. Methods: Before clinical PGD, we assessed the amplification rate and allele drop-out (ADO) rate of multiplex fluorescent polymerase chain reaction (PCR) followed by fragment analysis or sequencing using single lymphocytes. We performed six cycles of PGD for CMT1A and one cycle for CMT2F. Results: Two duplex and two triplex protocols were developed according to the available markers for each CMT1A couple. Depending on the PCR protocols, the amplification rates and ADO rates ranged from 90.0% to 98.3% and 0.0% to 11.1%, respectively. For CMT2F, the amplification rates and ADO rates were 93.3% and 4.8%, respectively. In case of CMT1A, 60 out of 63 embryos (95.2%) were diagnosed and 13 out of 21 unaffected embryos were transferred in five cycles. Two pregnancies were achieved and three babies were delivered without any complications. In the case of CMT2F, a total of eight embryos were analyzed and diagnosed. Seven embryos were diagnosed as unaffected and four embryos were transferred, resulting in a twin pregnancy. Two healthy babies were delivered. Conclusion: This is the first report of successful pregnancy and delivery after specific PGD for CMT disease in Korea. Our PGD procedure could provide healthy babies to couples with a high risk of transmitting genetic diseases.

• Research in Plant Disease
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• v.23 no.3
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• pp.234-240
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• 2017

Incidence of virus diseases in red pepper of open field in Yeongyang-Gun, Gyeongbuk Province was investigated by reverse transcription-polymerase chain reaction in 2012-2016. The infection rate of Cucumber mosaic virus (CMV), Broad bean wilt virus 2 (BBWV2), Pepper mottle virus, Potato virus Y, Pepper mild mottle virus and Tomato spotted wilt virus was 46.1%, 41.5%, 2.0%, 2.0%, 4.4% and 0.1% respectively. Incidence rate of single and mixed infection was 31.2% and 62.6%. Most of single infections were CMV and BBWV2. Among mixed infections, the incidence rate of CMV+BBWV2 mixed infection was the highest as 49.3% and most of mixed infections of triplex and tetraplex included CMV+BBWV2 mixed infection. CMV single infection caused mosaic, chlorosis, yellowing and vein necrosis and BBWV2 single infection induced cholosis and mosaic. CMV+BBWV2 mixed infection caused severe mosaic with chlorosis or malformation.