• Title/Summary/Keyword: Quantitative Real-time Polymerase Chain Reaction (qRT-PCR)

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Clinicopathological Significance of BRCA1 Promoter Hypermethylation in Thai Breast Cancer Patients

  • Saelee, Pensri;Chaiwerawattana, Arkom;Ogawa, Kumiko;Cho, Young-Man;Tiwawech, Danai;Suktangman, Vimol
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.24
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    • pp.10585-10589
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    • 2015
  • Breast cancer susceptibility gene 1 (BRCA1), mapped on chromosome 17q21, is implicated in the mechanisms of cellular DNA repair. Inactivation of this gene is involved in the development of many human cancers, including breast cancer. This study aimed to investigate the prognostic value of BRCA1 promoter hypermethylation and expression in breast cancer cases. Sixty-one breast cancers were examined for BRCA1 hypermethylation by methylation-specific polymerase chain reaction (PCR), and 45 paired normal breast tissues were analyzed for altered BRCA1 mRNA levels by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Aberrant methylation status in BRCA1 was detected in 15 of 61 cases (24.6%), while reduced expression was found in 7 of 45 (15.6%). BRCA1 hypermethylation was statistically associated with tumor grade III (p=0.04), a high frequency of stage IIB (p=0.02), and triple-negative phenotype (OR= 3.64, 95%CI =1.1-12.3, p=0.03). Our findings indicated that BRCA1 promoter hypermethylation is a useful prognostic marker for breast cancer.

Comparison of microbial molecular diagnosis efficiency within unstable template metagenomic DNA samples between qRT-PCR and chip-based digital PCR platforms

  • Dongwan Kim;Junhyeon Jeon;Minseo Kim;Jinuk Jeong;Young Mok Heo;Dong-Geol Lee;Dong Keon Yon;Kyudong Han
    • Genomics & Informatics
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    • v.21 no.4
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    • pp.52.1-52.10
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    • 2023
  • Accurate and efficient microbial diagnosis is crucial for effective molecular diagnostics, especially in the field of human healthcare. The gold standard equipment widely employed for detecting specific microorganisms in molecular diagnosis is quantitative real-time polymerase chain reaction (qRT-PCR). However, its limitations in low metagenomic DNA yield samples necessitate exploring alternative approaches. Digital PCR, by quantifying the number of copies of the target sequence, provides absolute quantification results for the bacterial strain. In this study, we compared the diagnostic efficiency of qRT-PCR and digital PCR in detecting a particular bacterial strain (Staphylococcus aureus), focusing on skin-derived DNA samples. Experimentally, specific primer for S. aureus were designed at transcription elongation factor (greA) gene and the target amplicon were cloned and sequenced to validate efficiency of specificity to the greA gene of S. aureus. To quantify the absolute amount of microorganisms present on the skin, the variable region 5 (V5) of the 16S rRNA gene was used, and primers for S. aureus identification were used to relative their amount in the subject's skin. The findings demonstrate the absolute convenience and efficiency of digital PCR in microbial diagnostics. We suggest that the high sensitivity and precise quantification provided by digital PCR could be a promising tool for detecting specific microorganisms, especially in skin-derived DNA samples with low metagenomic DNA yields, and that further research and implementation is needed to improve medical practice and diagnosis.

Effect of Tetrodotoxin on the Proliferation and Gene Expression of Human SW620 Colorectal Cancer Cells

  • Bae, Yun-Ho;Kim, Hun;Lee, Sung-Jin
    • Biomedical Science Letters
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    • v.28 no.1
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    • pp.42-49
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    • 2022
  • Tetrodotoxin (TTX) is a natural neurotoxin found in several species of puffer fish belonging to Tetraodon fugu genus and has been reported to affect processes such as proliferation, metastasis and invasion of various cancer cells. However, it was not revealed which genes were influenced by these reactions. In this experiment, it was examined in human SW620 colorectal cancer cells. The proliferation of SW620 cells was significantly reduced when treated with 0, 1, 10 and 100 μM TTX for 48 h. It was confirmed using Annexin V-propidium iodide staining that some apoptosis was induced. Differentially expressed genes (DEGs) affecting cell proliferation through RNA sequencing (RNA-seq) were selected. The expression change of DEGs was confirmed by conducting quantitative real-time polymerase chain reaction (qRT-PCR). As a result, the mRNA expression of FOS and WDR48 genes was found to be increased in the 100 μM TTX treatment group compared to the control group. On the other hand, the mRNA expression of ALKBH7, NDUFA13, RIPPLY3 and SELENOM genes was found to be reduced, and in the case of the ALKBH7 gene was identified to show significant differences. This experiment suggests that TTX can be used as an important fundamental data to elucidate the mechanism that inhibits the proliferation of SW620 cells.

A LuxR-type Transcriptional Regulator, PsyR, Coordinates Regulation of Pathogenesis-related Genes in Pseudomonas syringae pv. tabaci (Pseudomonas syringae pv. tabaci 에서 LuxR-type 전사조절자인 PsyR에 의한 병원성 유전자들의 조절)

  • Choi, Yeon Hee;Lee, Jun Seung;Yun, Sora;Baik, Hyung Suk
    • Journal of Life Science
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    • v.25 no.2
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    • pp.136-150
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    • 2015
  • Pseudomonas syringae pathovar tabaci is a plant pathogenic bacterium that causes wildfire disease in tobacco plants. In P. syringae pv. tabaci, PsyI, a LuxI-type protein, acts as an AHL synthase, while primary and secondary sequence analysis of PsyR has revealed that it is a homolog of the LuxR-type transcriptional regulator that responds to AHL molecules. In this study, using phenotypic and genetic analyses in P. syringae pv. tabaci, we show the effect of PsyR protein as a quorum-sensing (QS) transcriptional regulator. Regulatory effects of PsyR on swarming motility and production of siderophores, tabtoxin, and N-acyl homoserine lactones were examined via phenotypic assays, and confirmed by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Further qRT-PCR showed that PsyR regulates expression of these virulence genes in response to environmental signals. However, an upstream region of the gene was not bound with purified MBP-PsyR protein; rather, PsyR was only able to shift the upstream region of psyI. These results suggested that PsyR may be indirectly controlled via intermediate-regulatory systems and that auto-regulation by PsyR does not occur.

Development of a multiplex qRT-PCR assay for detection of African swine fever virus, classical swine fever virus and porcine reproductive and respiratory syndrome virus

  • Chen, Yating;Shi, Kaichuang;Liu, Huixin;Yin, Yanwen;Zhao, Jing;Long, Feng;Lu, Wenjun;Si, Hongbin
    • Journal of Veterinary Science
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    • v.22 no.6
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    • pp.87.1-87.12
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    • 2021
  • Background: African swine fever virus (ASFV), classical swine fever virus (CSFV), and porcine reproductive and respiratory syndrome virus (PRRSV) are still prevalent in many regions of China. Co-infections make it difficult to distinguish their clinical symptoms and pathological changes. Therefore, a rapid and specific method is needed for the differential detection of these pathogens. Objectives: The aim of this study was to develop a multiplex real-time quantitative reverse transcription polymerase chain reaction (multiplex qRT-PCR) for the simultaneous differential detection of ASFV, CSFV, and PRRSV. Methods: Three pairs of primers and TaqMan probes targeting the ASFV p72 gene, CSFV 5' untranslated region, and PRRSV ORF7 gene were designed. After optimizing the reaction conditions, including the annealing temperature, primer concentration, and probe concentration, multiplex qRT-PCR for simultaneous and differential detection of ASFV, CSFV, and PRRSV was developed. Subsequently, 1,143 clinical samples were detected to verify the practicality of the assay. Results: The multiplex qRT-PCR assay could specifically and simultaneously detect the ASFV, CSFV, and PRRSV with a detection limit of 1.78 × 100 copies for the ASFV, CSFV, and PRRSV, but could not amplify the other major porcine viruses, such as pseudorabies virus, porcine circovirus type 1 (PCV1), PCV2, PCV3, foot-and-mouth disease virus, porcine parvovirus, atypical porcine pestivirus, and Senecavirus A. The assay had good repeatability with coefficients of variation of intra- and inter-assay of less than 1.2%. Finally, the assay was used to detect 1,143 clinical samples to evaluate its practicality in the field. The positive rates of ASFV, CSFV, and PRRSV were 25.63%, 9.36%, and 17.50%, respectively. The co-infection rates of ASFV+CSFV, ASFV+PRRSV, CSFV+PRRSV, and ASFV+CSFV+PRRSV were 2.45%, 2.36%, 1.57%, and 0.17%, respectively. Conclusions: The multiplex qRT-PCR developed in this study could provide a rapid, sensitive, specific diagnostic tool for the simultaneous and differential detection of ASFV, CSFV, and PRRSV.

Gene Expression Analysis of Pregnant Specific Stage in the Miniature Pig Ovary

  • Yun, Seong-Jo;Noh, Won-Gun;Yoon, Jong-Taek;Min, Kwan-Sik
    • Reproductive and Developmental Biology
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    • v.33 no.4
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    • pp.249-255
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    • 2009
  • The miniature pig is considered to be a better organ donor breed for xenotransplantation than other pig breeds because the size of the organs of the miniature pig is similar to that of humans. In this study, we aimed at identifying differentially expressed genes in the miniature pig ovary during pregnancy. For this, we used the miniature pig ovary model, annealing control primer-based reverse transcription polymerase chain reaction (PCR), quantitative real-time PCR (qRT-PCR), and northern blotting analysis. We identified 13 genes showing differential expression on the based of pregnancy status and validated 8 genes using qRT-PCR. We also sequenced the full-length cDNA of ephrin receptor A4 (EphA4), which had a significant difference in expression level, and validated it by northern blotting. These genes may provide a better understanding of the cellular and molecular mechanisms during pregnancy in miniature pig ovary.

Optimization of Reference Genes for Normalization of the Quantitative Polymerase Chain Reaction in Tissue Samples of Gastric Cancer

  • Zhao, Lian-Mei;Zheng, Zhao-Xu;Zhao, Xiwa;Shi, Juan;Bi, Jian-Jun;Pei, Wei;Feng, Qiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5815-5818
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    • 2014
  • For an exact comparison of mRNA transcription in different samples or tissues with real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), it is crucial to select a suitable internal reference gene. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin (ACTB) have been frequently considered as house-keeping genes to normalize for changes in specific gene expression. However, it has been reported that these genes are unsuitable references in some cases, because their transcription is significantly variable under particular experimental conditions and among tissues. The present study was aimed to investigate which reference genes are most suitable for the study of gastric cancer tissues using qRT-PCR. 50 pairs of gastric cancer and corresponding peritumoral tissues were obtained from patients with gastric cancer. Absolute qRT-PCR was employed to detect the expression of GAPDH, ACTB, RPII and 18sRNA in the gastric cancer samples. Comparing gastric cancer with corresponding peritumoral tissues, GAPDH, ACTB and RPII were obviously upregulated 6.49, 5.0 and 3.68 fold, respectively. Yet 18sRNA had no obvious expression change in gastric cancer tissues and the corresponding peritumoral tissues. The expression of GAPDH, ${\beta}$-actin, RPII and 18sRNA showed no obvious changes in normal gastric epithelial cells compared with gastric cancer cell lines. The carcinoembryonic antigen (CEA), a widely used clinical tumor marker, was used as a validation gene. Only when 18sRNA was used as the normalizing gene was CEA obviously elevated in gastric cancer tissues compared with peritumoral tissues. Our data show that 18sRNA is stably expressed in gastric cancer samples and corresponding peritumoral tissues. These observations confirm that there is no universal reference gene and underline the importance of specific optimization of potential reference genes for any experimental condition.

Anti-Helicobacter and Anti-inflammatory Effects of Sohamhyungtang in Helicobacter pylori-Infected Human Gastric Epithelial AGS cells

  • Won, SangBum;Yim, Dongsool;Choi, SungSook
    • Natural Product Sciences
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    • v.23 no.3
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    • pp.175-182
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    • 2017
  • This study evaluated the anti-Helicobacter and anti-inflammatory effects of Sohamhyungtang (SHHT). The minimum inhibitory concentration (MIC) of SHHT against Helicobacter pylori (H. pylori) was determined by the agar dilution method. Expression of the H. pylori cagA gene in the presence of SHHT was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Inhibition of H. pylori urease by SHHT was determined by the phenol-hypochlorite assay. Antiadhesion activity of SHHT was measured by urea-phenol red reagent. Inhibition of nitric oxide (NO) production in AGS cells was measured with Griess reagent. Inducible nitric oxide synthase (iNOS) and IL-8 mRNA expression in AGS cells which were infected with H. pylori was determined by qRT-PCR. IL-8 level was measured by enzyme-linked immunosorbent assay (ELISA). The MIC of SHHT was $100{\mu}g/mL$ and the expression of cagA gene was decreased about 25 folds in the presence of SHHT. H. pylori urease was inhibited 90% by SHHT. SHHT inhibited H. pylori adhesion on AGS cell in a concentration dependent manner. mRNA expression of iNOS and IL-8 and the production of NO and IL-8 were significantly decreased in the presence of SHHT. In conclusion, SHHT showed anti-Helicobacter activity and has potent anti-inflammatory effect on H. pylori-induced inflammation in human gastric epithelial AGS cells.

Discovery of a new primer set for detection and quantification of Ilyonectria mors-panacis in soils for ginseng cultivation

  • Farh, Mohamed El-Agamy;Han, Jeong A.;Kim, Yeon-Ju;Kim, Jae Chun;Singh, Priyanka;Yang, Deok-Chun
    • Journal of Ginseng Research
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    • v.43 no.1
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    • pp.1-9
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    • 2019
  • Background: Korean ginseng is an important cash crop in Asian countries. However, plant yield is reduced by pathogens. Among the Ilyonectria radicicola-species complex, I. mors-panacis is responsible for root-rot and replant failure of ginseng in Asia. The development of new methods to reveal the existence of the pathogen before cultivation is started is essential. Therefore, a quantitative real-time polymerase chain reaction method was developed to detect and quantify the pathogen in ginseng soils. Methods: In this study, a species-specific histone H3 primer set was developed for the quantification of I. mors-panacis. The primer set was used on DNA from other microbes to evaluate its sensitivity and selectivity for I. mors-panacis DNA. Sterilized soil samples artificially infected with the pathogen at different concentrations were used to evaluate the ability of the primer set to detect the pathogen population in the soil DNA. Finally, the pathogen was quantified in many natural soil samples. Results: The designed primer set was found to be sensitive and selective for I. mors-panacis DNA. In artificially infected sterilized soil samples, using quantitative real-time polymerase chain reaction the estimated amount of template was positively correlated with the pathogen concentration in soil samples ($R^2=0.95$), disease severity index ($R^2=0.99$), and colony-forming units ($R^2=0.87$). In natural soils, the pathogen was recorded in most fields producing bad yields at a range of $5.82{\pm}2.35pg/g$ to $892.34{\pm}103.70pg/g$ of soil. Conclusion: According to these results, the proposed primer set is applicable for estimating soil quality before ginseng cultivation. This will contribute to disease management and crop protection in the future.

Selection and evaluation of reference genes for gene expression using quantitative real-time PCR in Mythimna separata walker (Lepidoptera: Noctuidae)

  • ZHANG, Bai-Zhong;LIU, Jun-Jie;CHEN, Xi-Ling;YUAN, Guo-Hui
    • Entomological Research
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    • v.48 no.5
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    • pp.390-399
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    • 2018
  • In order to precisely assess gene expression levels, the suitable internal reference genes must be served to quantify real-time reverse transcription polymerase chain reaction (RT-qPCR) data. For armyworm, Mythimna separata, which reference genes are suitable for assessing the level of transcriptional expression of target genes have yet to be explored. In this study, eight common reference genes, including ${\beta}$-actin (${\beta}$-ACT), 18 s ribosomal (18S), 28S ribosomal (28S), glyceraldehyde-3-phosphate (GAPDH), elongation fator-alpha ($EF1{\alpha}$), TATA box binding protein (TBP), ribosomal protein L7 (RPL7), and alpha-tubulin (${\alpha}$-TUB) that in different developmental stages, tissues and insecticide treatments of M. separata were evaluated. To further explore whether these genes were suitable to serve as endogenous controls, three software-based approaches (geNorm, BestKeeper, and NormFinder), the delta Ct method, and one web-based comprehensive tool (RefFinder) were employed to analyze and rank the tested genes. The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated according to normalized HSP70, and MsepCYP321A10 gene expression data. We found that the most suitable reference genes for the different experimental conditions. For developmental stages, 28S/RPL7 were the optimal reference genes, both $RPL7/EF1{\alpha}$ were suitable for experiments of different tissues, whereas for insecticide treatments, $28S/{\alpha}-TUB$ were suitable for normalizations of expression data. In addition, $28S/{\alpha}-TUB$ were the suitable reference genes because they have the most stable expression among different developmental stages, tissues and insecticide treatments. Our work is the first report on reference gene selection in M. separata, and might serve as a precedent for future gene expression studies.