• Korean Journal of Veterinary Service
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• v.46 no.2
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• pp.123-135
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• 2023

Feline calicivirus (FCV) is considered the main viral pathogen of feline upper respiratory tract disease (URTD). The frequent mutations of field FCV strains result in the poor diagnostic sensitivity of previously developed molecular diagnostic assays. In this study, a more sensitive real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for broad detection of currently circulating FCVs and comparatively evaluated the diagnostic performance with previously developed qRT-PCR assay using clinical samples collected from Korean cat populations. The developed qRT-PCR assay specifically amplified the FCV p30 gene with a 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 2%. Based on the clinical evaluation using 94 clinical samples obtained from URTD-suspected cats, the detection rate of FCV by the developed qRT-PCR assay was 47.9%, which was higher than that of the previous qRT-PCR assay (43.6%). The prevalence of FCV determined by the new qRT-PCR assay in this study was much higher than those of previous Korean studies determined by conventional RT-PCR assays. Due to the high sensitivity, specificity, and accuracy, the new qRT-PCR assay developed in this study will serve as a promising tool for etiological and epidemiological studies of FCV circulating in Korea. Furthermore, the prevalence data obtained in this study will contribute to expanding knowledge about the epidemiology of FCV in Korea.

• Research in Plant Disease
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• v.27 no.3
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• pp.120-127
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• 2021

Plant viruses cause significant yield losses, continuously compromising crop production and thus representing a serious threat to global food security. Tomato spotted wilt virus (TSWV) is the most harmful plant virus that mainly infects horticultural crops and has a wide host range. Reverse-transcription quantitative real-time PCR (RT-qPCR) has been widely used for detecting TSWV with high sensitivity, but its application is limited owing to the lack of standardization. Therefore, in this study, a sensitive and accurate reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) method was established for TSWV detection. Additionally, we compared the sensitivities of RT-qPCR and RT-ddPCR for TSWV detection. Specificity analysis of RT-ddPCR for TSWV showed no amplification for main pepper viruses and negative control. TSWV transcripts levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity; however, the former yielded results that were at least 10-fold more sensitive and detected lower TSWV copy numbers than the latter. Collectively, our findings show that RT-ddPCR provides improved analytical sensitivity and specificity for TSWV detection, making it suitable for identifying low TSWV concentrations in field samples.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7621-7628
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• 2013

Human epidermal growth factor receptor (HER) status is an important prognostic factor in breast cancer. There is no globally accepted method for determining its status, and which method is most precise is still a matter of debate. We here analyzed HER2 mRNA expression by quantitative reverse transcription-PCR (qRT-PCR) and HER2 DNA amplification using multiplex ligation-dependent probe amplification (MLPA). In parallel, we performed a routine evaluation of HER2 protein by immunohistochemistry (IHC). To assess the accuracy of the RT-PCR and MLPA techniques, a combination of IHC and fluorescence in situ hybridization (FISH) was used, substituting FISH when the results of IHC were ambiguous (2+) and for those IHC results that disagreed with MLPA and qRT-PCR, this approach being termed IHC-FISH. The IHC results for four samples were not compatible with the MLPA and qRT-PCR results; the MLPA and qRT-PCR results for these samples were confirmed by FISH. The correlations between IHC-FISH and qRT-PCR or MLPA were 0.945 and 0.973, respectively. The ASCO/CAP guideline IHC/FISH correlation with MLPA was (0.827) and with RT-PCR was (0.854). The correlations between the IHC results (0, 1+ as negative, and 3+ as positive) and qRT-PCR and MLPA techniques were 0.743 and 0.831, respectively. Given the shortcomings of IHC analysis and greater correlations between MLPA, qRT-PCR, and FISH methods than IHC analysis alone with each of these three methods, we propose that MLPA and real-time PCR are good alternatives to IHC. However a suitable cut-off point for qRTPCR is a prerequisite for determining the exact status of HER2.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.367-376
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• 2011

BACKGROUND: In order to develop effective assessment method for Korean paddy soil microbial community structure, reliable genomic DNA extraction method from paddy soil and quantitative real-time PCR (qRT-PCR) method are needed to establish METHODS AND RESULTS: Out of six conventional soil genomic DNA extraction methods, anion exchange resin purification method was turn to be the most reliable. Various PCR primers for distinguishing five bacterial phylum (${\alpha}$-Proteobacteria, ${\beta}$-Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes), all bacteria, and all fungi were tested. Various qRT-PCR temperature conditions were also tested by repeating experiment. Finally, both genomic DNA extraction and qRT-PCR methods for paddy soil were well established. CONCLUSION: Quantitative real-time PCR (qRT-PCR) method to assess paddy soil microbial community was established.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.816-824
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• 2017

Human noroviruses are widespread and contagious viruses causing nonbacterial gastroenteritis. Real-time reverse transcription quantitative PCR (real-time RT-qPCR) is currently the gold standard for the sensitive and accurate detection of these pathogens and serves as a critical tool in outbreak prevention and control. Different surveillance teams, however, may use different assays, and variability in specimen conditions may lead to disagreement in results. Furthermore, the norovirus genome is highly variable and continuously evolving. These issues necessitate the re-examination of the real-time RT-qPCR's robustness in the context of accurate detection as well as the investigation of practical strategies to enhance assay performance. Four widely referenced real-time RT-qPCR assays (Assays A-D) were simultaneously performed to evaluate characteristics such as PCR efficiency, detection limit, and sensitivity and specificity with RT-PCR, and to assess the most accurate method for detecting norovirus genogroups I and II. Overall, Assay D was evaluated to be the most precise and accurate assay in this study. A ZEN internal quencher, which decreases nonspecific fluorescence during the PCR, was added to Assay D's probe, which further improved the assay performance. This study compared several detection assays for noroviruses, and an improvement strategy based on such comparisons provided useful characterizations of a highly optimized real-time RT-qPCR assay for norovirus detection.

• Biomedical Science Letters
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• v.22 no.3
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• pp.83-97
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• 2016

The measurement of viral load in HIV-1 infected patients is essential for the establishment of a therapeutic strategy. Several commercial assays have shown shortcomings in quantifying rare genotypes of HIV-1 such as minor groups of N and O. In this study, the HIV-1 RT-qPCR assay was developed. The primers and probe of HIV-1 were designed to target the pol gene and to increase the detection efficiency of various subtypes including group N and O. The HIV-1 quantitative RT-qPCR assay was assessed for its analytical performance and clinical evaluation. The LoD was determined to 33.9 IU/ml. The LoD of several subtypes including A, C, D, CRF_01AE, F, CRF_02AG, G and H, were determined to less than 40 IU/ml. The HIV-1 quantitative RT-qPCR assay was evaluated using the China National Reference Panel of HIV-1 RNA to determine the analytical performance. The results were all within the acceptable range. The clinical evaluation was performed at Hunan CDC in China. The clinical evaluation results were compared with those of the China domestic commercial kit. A significant correlation (fresh samples; $R^2=0.84$, P<0.001, frozen samples; $R^2=0.76$, P<0.001) between the two systems was observed for 64 fresh samples and 76 frozen samples with viral loads, and the Bland-Altman plot showed good agreement (98.4%, 96.1%, respectively). In conclusion, the HIV-1 quantitative RT-qPCR assay had comparable analytical performance with several commercial kits. The study provides basic data for the research of HIV-1 diagnosis and the development of P < HIV-1 molecular diagnostic assay.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.4
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• pp.312-318
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• 2015

The aim of this study was to investigate the possibility of the supernumerary teeth for the stem cell source in dentistry. The Real Time Quantitative Reverse Transcription Polymerase Chain Reaction (Real Time qRT-PCR) method was used to evaluate the differentiation toward the odontoblast of the supernumerary dental pulp stem cells (sDPSCs). Supernumerary dental pulp stem cells were obtained from 3 children (2 males and 1 female, age 7 to 9) diagnosed that the eruption of permanent teeth was disturbed by supernumerary teeth. The common genes for odontoblasts are alkaline phosphatase (ALP), osteocalcin (OC), osteonectin (ON), dentin matrix acidic phosphoprotein 1 (DMP-1), dentin sialophosphoprotein (DSPP). The sDPSCs were treated for 0 days, 8 days and 14 days with additives and then Real Time qRT-PCR was performed in intervals of 0 days, 8 days and 14 days. The alizarin-red solution staining was performed to visualize the stained color for the degree of calcification at 7 days, 14 days, 21 days and 28 days after treating additives to the sDPSCs. From the result of the Real Time qRT-PCR, the manifestation exhibit maximum value at 8 days after additive treatment and shifted to a decrease trend at 14 days. Alizarin-red solution staining exhibit light results at 7 days after staining and generalized dark result at 14 days. Consequently, in studies with sDPSCs, appropriate treatment time of additives for Real Time qRT-PCR is 8 days. Also, a suitable period of Alizarin-red solution staining is 14 days.

• Journal of Life Science
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• v.29 no.6
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• pp.653-661
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• 2019

The first small interfering RNA (siRNA) therapeutics have recently been approved by the Food and Drug Administration in the U.S., and the demand for a new RNA therapeutics bioanalysis method-which is essential for pharmacokinetics, including the absorption, distribution, metabolism, and excretion of siRNA therapeutics-is rapidly increasing. The stem-loop real-time qPCR (RT-qPCR) assay is a useful molecular technique for the identification and quantification of small RNA (e.g., micro RNA and siRNA) and can be applied for the bioanalysis of siRNA therapeutics. When the anti-HPV E6/E7 siRNA therapeutic was used in preclinical trials, the established stem-loop RT-qPCR assay was validated. The limit of detection was sensitive up to 10 fM and the lower limit of quantification up to 100 fM. In fact, the reliability of the established test method was further validated in three intra assays. Here, the correlation coefficient of $R^2$>0.99, the slope of -3.10 ~ -3.40, and the recovery rate within ${\pm}20%$ of the siRNA standard curve confirm its excellent robustness. Finally, the circulation profiles of siRNAs were demonstrated in rat serum, and the pharmacokinetic properties of the anti-HPV E6/E7 siRNA therapeutic were characterized using a stem-loop RT-qPCR assay. Therefore, the stemloop RT-qPCR assay enables accurate, precise, and sensitive siRNA duplex quantification and is suitable for the quantification of small RNA therapeutics using small volumes of biological samples.

• International Journal of Oral Biology
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• v.36 no.1
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• pp.1-6
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• 2011

The purpose of this study was to develop species-specific real-time quantitative PCR (RT-qPCR) primers for use in the detection of Aggregatibacter actinomycetemcomitans. These primers were designed based on the nucleotide sequences of the RNA polymerase ${\beta}$-subunit gene (rpoB). We assessed the specificity of the primers against nine strains of A. actinomycetemcomitans, eight strains (three species) of the Haemophilus genus, and 40 strains of 40 other oral bacterial species. Primer sensitivity was determined by testing serial dilutions of the purified genomic DNAs of A. actinomycetemcomitans ATCC $33384^T$. Our data reveal that we had obtained species-specific amplicons for all of the tested A. actinomycetemcomitans strains, and that none of these amplicons occurred in any of the other species. Our PCR protocol proved able to detect as little as 2 fg of A. actinomycetemcomitans chromosomal DNA. Our findings suggest that these qRT-PCR primers are suitable for application in epidemiological studies.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.270-274
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• 2013

The bumblebee, Bombus terrestris, has played an important role as one of the alternative pollinators since the outbreak of honeybee collapse disorder. Recently, pathogens and parasites such as viruses, bacteria and mites, which affect the life span and fecundity of their host, have been discovered in B. terristris. In order to detect the microsporidian pathogen, Nosema spp. in the field populations of B. terristris, we collected adults and isolated their genomic DNA for diagnostic PCR. The PCR primers specific for Nosema spp. were newly designed and applied to gene amplification for cloning. Only small subunit ribosomal RNA (SSU rRNA) gene of N. ceranae was successfully amplified among examined genes and sequenced, which indicates that N. ceranae mainly infects the examined field population of B. terristris. To detect of SSU rRNA gene, two regions of SSU rRNA gene were selected by primary PCR analysis and further analyzed in quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis demonstrated that SSU rRNA of N. ceranae was detected at concentration as low as $0.85ng/{\mu}l$ genomic DNA. This result suggests that the detection via qRT-PCR can be applied for the rapid and sensitive diagnosis of N. ceranae infection in the field population as well as risk assessment of B. terristris.