• International Journal of Oral Biology
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• v.46 no.3
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• pp.140-145
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• 2021

This study aimed to develop Lautropia mirabilis-specific quantitative real-time polymerase chain reaction (qPCR) primers based on the sequence of DNA-directed RNA polymerase subunit beta gene. The PrimerSelect program was used in designing of the qPCR primers, RTLam-F4 and RTLam-R3. The specificity of the qPCR primers were performed by conventional PCR with 37 strains of 37 oral bacterial species, including L. mirabilis. The sensitivity of the primers was determined by qPCR with the serial dilution of purified genomic DNA of L. mirabilis KCOM 3484, ranged from 4 ng to 4 fg. The data showed that the qPCR primers could detect only L. mirabilis strains and as little as 40 fg of genome DNA of L. mirabilis KCOM 3484. These results indicate that this qPCR primer pair (RTLam-F4/RTLam-R3) may be useful for species-specific detection of L. mirabilis in epidemiological studies of oral bacterial infectious diseases such as periodontal disease.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.847-859
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• 2022

The development and commercialization of industrial genetically modified (GM) organisms is actively progressing worldwide, highlighting an increased need for improved safety management protocols. We sought to establish an environmental monitoring method, using real-time polymerase chain reaction (PCR) and propidium monoazide (PMA) treatment to develop a quantitative detection protocol for living GM microorganisms. We developed a duplex TaqMan quantitative PCR (qPCR) assay to simultaneously detect the selectable antibiotic gene, ampicillin (AmpR), and the single-copy Escherichia coli taxon-specific gene, D-1-deoxyxylulose 5-phosphate synthase (dxs), using a direct cell suspension culture. We identified viable engineered E. coli cells by performing qPCR on PMA-treated cells. The theoretical cell density (true copy numbers) calculated from mean quantification cycle (Cq) values of PMA-qPCR showed a bias of 7.71% from the colony-forming unit (CFU), which was within ±25% of the acceptance criteria of the European Network of GMO Laboratories (ENGL). PMA-qPCR to detect AmpR and dxs was highly sensitive and was able to detect target genes from a 10,000-fold (10^-4) diluted cell suspension, with a limit of detection at 95% confidence (LOD_95%) of 134 viable E. coli cells. Compared to DNA-based qPCR methods, the cell suspension direct PMA-qPCR analysis provides reliable results and is a quick and accurate method to monitor living GM E. coli cells that can potentially be released into the environment.

• 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.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.205-210
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• 2015

Prevotella intermedia-specific quantitative real-time PCR (qPCR) primers were previously designed based on the nucleotide sequences of RNA polymerase ${\beta}$-subunit gene (rpoB). However, the several clinical strains isolated from Korean populations are not detectable by the qPCR primers. The purpose of this study was to develop new P. intermedia-specific qPCR primers based on the rpoB. The specificity of the primers was determined by conventional PCR with 12 strains of P. intermedia and 52 strains (52 species) of non-P. intermedia bacteria. The sensitivity of primers was determined by qPCR with serial dilutions of the purified genomic DNAs (40 ng to 4 fg) of P. intermedia ATCC $25611^T$. The data indicated that only P. intermedia strains were detected by the P intermedia-specific qPCR primers (RTPiF2/RTPiR2); in addition, as little as 40 fg of P. intermedia genomic DNA could be detected. These results suggest that these qPCR primers are useful in detecting P. intermedia from the bacterial infectious lesions including dental plaque and oral tissue lesions.

• Journal of Veterinary Science
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• v.22 no.3
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• pp.40.1-40.12
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• 2021

Background: The microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen. Objectives: The present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees. Methods: A procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration. Results: UR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min. Conclusions: UR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.149-154
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• 2016

The purpose of this study was to develop Streptococcus sobrinus-specific qPCR primers based on the nucleotide sequence of the RNA polymerase ${\beta}-subunit$ gene (rpoB). The specificity of the primers was determined by conventional polymerase chain reaction (PCR) with 12 strains of S. sobrinus and 50 strains (50 species) of non-S. sobrinus bacteria. The sensitivity of the primers was determined by quantitative real-time PCR (qPCR) with serial dilutions of the purified genomic DNAs (40 ng to 4 fg) of S. sobrinus ATCC $33478^T$. The specificity data showed that the S. sobrinus-specific qPCR primers (RTSsob-F4/RTSsob-R4) detected only the genomic DNAs of S. sobrinus strains with a detection limit of up to 4 fg of S. sobrinus genomic DNA. Our results suggest that the RTSsob-F4/RTSsob-R4 primers are useful in detecting S. sobrinus with high sensitivity and specificity for epidemiological studies of dental caries..

• International Journal of Oral Biology
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• v.44 no.3
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• pp.96-100
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• 2019

The purpose of this study was to develop Peptoniphilus mikwangii-specific quantitative real-time polymerase chain reaction (qPCR) primers based on the 16S ribosomal RNA (16S rDNA) gene. The specificity of the primers was determined by conventional PCR using 29 strains of 27 oral bacterial species including P. mikwangii. The sensitivity of the primers was determined by qPCR using the purified genomic DNA of P. mikwangii KCOM $1628^T$ (40 ng to 4 fg). The data showed that the qPCR primers (RTB134-F4/RTB134-R4) could detect P. mikwangii strains exclusively and as little as 40 fg of the genomic DNA of P. mikwangii KCOM $1628^T$. These results suggest that the developed qPCR primer pair can be useful for detecting P. mikwangii in epidemiological studies of oral bacterial infectious diseases.

• Genomics & Informatics
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• v.21 no.2
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• pp.24.1-24.7
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• 2023

Assays of clinical diagnosis and species identification using molecular markers are performed according to a quantitative method in consideration of sensitivity, cost, speed, convenience, and specificity. However, typical polymerase chain reaction (PCR) assay is difficult to quantify and have various limitations. In addition, to perform quantitative analysis with the quantitative real-time PCR (qRT-PCR) equipment, a standard curve or normalization using reference genes is essential. Within the last a decade, previous studies have reported that the digital PCR (dPCR) assay, a third-generation PCR, can be applied in various fields by overcoming the shortcomings of typical PCR and qRT-PCR assays. We selected Stilla Naica System (Stilla Technologies), Droplet Digital PCR Technology (Bio-Rad), and Lab on an Array Digital Real-Time PCR analyzer system (OPTOLANE) for comparative analysis among the various droplet digital PCR platforms currently in use commercially. Our previous study discovered a molecular marker that can distinguish Hanwoo species (Korean native cattle) using Hanwoo-specific genomic structural variation. Here, we report the pros and cons of the operation of each dPCR platform from various perspectives using this species identification marker. In conclusion, we hope that this study will help researchers to select suitable dPCR platforms according to their purpose and resources.

• Journal of Korean society of Dental Hygiene
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• v.17 no.2
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• pp.319-330
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• 2017

Objectives: The purpose of this study was to compare SYBR Green qPCR, TaqMan, and bacterial selective medium cultures for accurate quantitative analysis of oral microorganisms. Methods: The SYBR Green method is widely used to analyze the total amount of oral microorganisms in oral saliva. However, in this study, MTR-PCR method based on TaqMan method was performed using newly developed primers and probes. In addition, it was designed to confirm the detection agreement of bacteria among bacteria detection method. Results: As a result of MRT-PCR and SYBR Green qPCR analysis, more than 40 times (0.9-362.9 times) bacterium was detected by MRT-PCR. In addition, more bacteria were detected in saliva in the order of MRT-PCR, SYBR Green qPCR, and bacterium culture, and the results of MRB-PCR and SYBR Green qPCR showed the highest agreement. The agreement between the three methods for detecting P. intermedia was similar between 71.4 and 88.6%, but the agreement between MRT-PCR and SYBR Green qPCR was 80% for S. mutans. Among them, the number of total bacteria, P. intermedia and S. mutans bacteria in saliva was higher than that of SYBR Green qPCR method, and bacterium culture method by MRT-PCR method. P. intermedia and S. mutans in saliva were detected by MRT-PCR and MRT-PCR in 88.6% of cases, followed by the SYBR Green qPCR method (80.0%). Conclusions: The SYBR Green qPCR method is the same molecular biology method, but it can not analyze the germs at the same time. Bacterial culturing takes a lot of time if there is no selective culture medium. Therefore, the MRT-PCR method using newly developed primers and probes is considered to be the best method.

• 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.