• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.100-108
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• 2011

A method for the rapid detection and quantification of Newcastle disease virus (NDV) produced in an animal cell culture-based production system was developed to enhance the speed of the NDV vaccine manufacturing process. A SYBR Green I-based real-time RT-PCR was designed with a conventional, inexpensive RT-PCR kit targeting the F gene of the NDV LaSota strain. The method developed in this study was validated for specificity, accuracy, precision, linearity, limit of detection (LOD), limit of quantification (LOQ), and robustness. The validation results satisfied the predetermined acceptance criteria. The validated method was used to quantify virus samples produced in an animal cell culture-based production system. The method was able to quantify the NDV samples from mid- or late-production phases, but not effective on samples from the early-production phase. For comparison with other quantifiable methods, immunoblotting, plaque assay, and tissue culture infectious dose 50 ($TCID_{50}$) assay were also performed with the NDV samples. The results demonstrated that the real-time RT-PCR method is suitable for the rapid quantification of virus particles produced in an animal cell-culture-based production system irrespective of viral infectivity.

• 한국작물학회지
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• 제65권4호
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• pp.496-507
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• 2020

본 연구는 사과 바이러스 ASGV, ASPV 및 ApMV를 각각 정밀하게 진단하고자 SYBR Green I 및 TaqMan probe, 두 종류의 다른 chemical dye를 사용하여 quantitative real-time PCR 검정법을 개발하고자 하였다. 1. 사과 바이러스 ASGV, ASPV 및 ApMV의 국내분리주를 바탕으로 하여 cloning 및 in vitro transcription을 수행해 10배 희석단위 표준시료를 제작하였다. 각 바이러스에 대한 SYBR Green I용 프라이머와 TaqMan probe용 프라이머 및 프로브를 디자인하였다. 2. 상기 제작된 프라이머와 프로브를 이용해 표준시료를 대상으로 real-time PCR을 수행하여 각 바이러스의 증폭곡선과 검량선을 구할 수 있었다. Real-time PCR 결과, SYBR Green I기반의 검정법은 TaqMan probe기반의 검정법 못지 않은 결과를 보여주었으며, 적은 비용에 대량 검정이 요구되는 곳에 효과적으로 응용될 수 있을 것이다. 3. 현장평가를 본 실험에서 개발된 TaqMan probe기반의 real-time PCR검정법과 기존의 RT-PCR검정법과 비교분석하였다. 그 결과 real-time PCR 검정법은 singleplex 및 multiplex RT-PCR보다 더 민감하고 정확한 결과를 내어 RT-PCR로 검출할 수 없는 농도까지 검정할 수 있음을 입증하였다. 4. 본 실험에서 개발한 real-time PCR검정법은 검역현장과 같은 대량의 검사가 요구되는 곳에서는 SYBR Green I 기반의 검정법을, 바이러스 연구분야에서는 세밀한 정량이 가능한 TaqMan probe 방식의 검정법이 활용될 것으로 기대한다.

• The Plant Pathology Journal
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• 제27권4호
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• pp.385-389
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• 2011

A new reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the Potato leafroll virus (PLRV) was developed and compared with conventional reverse transcription polymerase chain reaction (RT-PCR) to address its advantages over RTPCR. RT-LAMP primers were designed from the open reading frame 3 (ORF3) sequence of PLRV. The RT-LAMP reactions were conducted without or with a set of loop primers. By real-time monitoring using Turbimeter, the RT-LAMP (with loop primers) detects PLRV in less than 30 min, compared to 120 min of RT-PCR. By adding fluorescent reagent during the reaction, final products of the RT-LAMP were fluorescently visualized under UV light or could be differentiated by naked-eye inspection under normal light. The RT-LAMP was extremely sensitive, about 2000-fold more sensitive than RT-PCR. This study presents great potential of the RT-LAMP for diagnosis and PLRV epidemiology because RT-LAMP method is speedy, sensitive, inexpensive, and convenient.

• 한국동물위생학회지
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• 제46권2호
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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.

• 미생물학회지
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• 제55권1호
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• pp.25-32
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• 2019

Influenza A (H1N1) virus caused a worldwide pandemic in 2009-2010 and still remains in seasonal circulation. Continuous surveillance activities are encouraged in the post pandemic phase to watch over the trend of occurrence every year, this is better to be done by a rapid and sensitive method for its detection. This study was conducted to detect proportions of occurrence of influenza A virus (H1N1) in patients with influenza-like illness. Samples from 500 patients with influenza or influenza-like clinical presentation were tested by real-time reverse transcription polymerase chain reaction (RT-PCR) and virus tissue culture. Among the total 500 participants, 193 (38.6%) were females and 307 (61.4%) males. Seventy-one patients (14.2%) were positive for H1N1 virus infection with real-time RT-PCR while 52 (10.4%) were positive by tissue culture. Non-statistically significant relation was found between age and gender with the positivity of H1N1. Sensitivity and specificity of real-time RT-PCR was 98.08% and 95.54%, respectively, in comparison to virus isolation with accuracy 95.8%. This study showed that H1N1 virus was responsible for a good proportion of influenza during the post-pandemic period. Real-time RT-PCR provides rapidity and sensitivity for the detection of influenza A virus (H1N1) compared with virus isolation and thus it is recommended as a diagnostic tool.

• 한국자원식물학회지
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• 제21권3호
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• pp.210-215
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• 2008

Gene-expression analysis is increasingly important in biological research, with real-time reverse PCR (RTPCR) becoming the method of choice for high-throughput and accurate expression profiling of selected genes. However, this technique requires important preliminary work for standardizing and optimizing the many parameters involved in the analysis. Plant stress studies are more and more based on gene expression. The analysis of gene expression requires sensitive and reproducible measurements for specific mRNA sequence. Several genes are regulated in response to abitoic stresses, such as salinity, and their gene products function in stress response and tolerance. The design of the primers and TaqMan probes for real-time PCR assays were carried out using the Primer $Express^{TM}$ software 3.0. The PCR efficiency was estimated through the linear regression of the dilution curve. To understand the expression pattern of various genes under salt stressed condition, we have developed a unique public resource of 9 stress-related genes in poplar. In this study, real-time RT-PCR was used to quantify the transcript level of 10 genes (9 stress-related genes and 1 house keeping gene) that could play a role in adaptation of Populus davidiana. Real-time RT-PCR analyses exhibited different expression ratios of related genes. The data obtained showed that determination of mRNA levels could constitute a new approach to study the stress response of P. davidiana after adaptation during growth in salinity condition.

• Journal of Microbiology and Biotechnology
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• 제22권8호
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• pp.1165-1169
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• 2012

In April 2009, the H1N1 pandemic influenza virus emerged as a novel influenza virus. The aim of this study was to compare the performances of several molecular assays, including conventional reverse transcription polymerase chain reaction (RT-PCR), two real-time reverse transcription (rRT)-PCRs, and two multiplex RTPCRs. A total of 381 clinical specimens were collected from patients (223 men and 158 women), and both the Seeplex RV7 assay and rRT-PCR were ordered on different specimens within one week after collection. The concordance rate for the two methods was 87% (332/381), and the discrepancy rate was 13% (49/381). The positive rates for the molecular assays studied included 93.1% for the multiplex Seeplex RV7 assay, 93.1% for conventional reverse transcription (cRT)-PCR, 89.7% for the multiplex Seeplex Flu ACE Subtyping assay, 82.8% for protocol B rRT-PCR, and 58.6% for protocol A rRT-PCR. Our results showed that the multiplex Seeplex assays and the cRT-PCR yielded higher detection rates than rRT-PCRs for detecting the influenza A (H1N1) virus. Although the multiplex Seeplex assays had the advantage of simultaneous detection of several viruses, they were time-consuming and troublesome. Our results show that, although rRT-PCR had the advantage, the detection rates of the molecular assays varied depending upon the source of the influenza A (H1N1)v virus. Our findings also suggest that rRT-PCR sometimes detected virus in extremely low abundance and thus required validation of analytical performance and clinical correlation.

• 한국식품저장유통학회지
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• 제30권2호
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• pp.262-271
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• 2023

본 연구에서는 real-time PCR(SureTect^TM kit와 PowerChek^TM kit), LAMP(3M MDS), 선택 배지를 이용하여 즉석섭취식품에 존재하는 Salmonella spp.와 L. monocytogenes의 검출 능력을 비교 및 평가하고 식품 매트릭스가 real-time PCR의 결과에 미치는 영향을 조사하였다. 4가지 서로 다른 농도로 접종된 식품을 동일한 증균배지를 이용하여 증균 후 세 가지 방법으로 검출한 결과, real-time PCR, LAMP, 선택 배지에서 모두 양성으로 검출되어 인위적으로 접종된 식품에서의 검출 성능은 동등한 것으로 나타났다. 또한, 식품 매트릭스가 real-time PCR의 신속 검출에 미치는 영향을 조사한 결과, Salmonella spp.의 검출에서 샐러드가 다른 식품에 비해 Ct value가 유의적으로 높은 것으로 나타나, 섬유질이 풍부한 식품에 존재하는 Salmonella spp.의 검출을 위해서는 충분한 균질화와 균체의 탈리, 그리고 효율적인 DNA의 증폭이 필요함을 알 수 있었다. 반면, L. monocytogenes의 검출은 식품 매트릭스마다 상이하며 혼합적인 양상을 보였다. 현재의 식품공전 규정에서 식품에 존재하는 식중독균의 신속 검출을 위한 장비와 시약의 사용은 대부분 사용자의 선택에 의존하고 있다. 본 실험에서 real-time PCR로 사용된 SureTect^TM kit와 PowerChek^TM kit는 기존 real-time PCR kit의 대체재로서 사용이 가능할 것으로 판단되며, 또한, LAMP도 우수한 검출 성능을 보였기에 식품안전 관리 수단으로 활용될 가능성이 있음을 시사하고 있다.

• 미생물학회지
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• 제44권3호
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• pp.228-236
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• 2008

세포배양 유래 생물의 약품 생산 공정에서 다양한 바이러스가 오염된 사례가 있기 때문에 바이러스 안전성 검증이 필수적이다. Reovirus type 3 (Reo-3)는 동물 세포주와 동물 세포 배양 공정에 오염되는 대표적인 바이러스이다. 세포배양 유래 생물의약품의 Reo-3 안전성을 확보하기 위해, 세포주, 원료물질, 제조공정, 완제품에서 Reo-3를 정략적으로 검출하고, 제조공정에서 Reo-3 제거 검증을 위한 시험법으로 활용이 가능한 real-time RT-PCR 시험법을 확립하였다. Reo-3에 특이적인 primer를 선별하였으며, 형광염료 SYBR Green I을 사용하여 Reo-3 RNA 정략 검출 시험법을 최적화하였다. 세포배양법에 의한 감염역가와 비교한 결과 real-time RT-PCR 민감도는 $3.2{\times}10^0\;TCID_{50}/ml$이었다. 확립된 시험법의 신뢰성(reliability)을 보증하기 위해 시험법 검증을 실시한 결과 특이성(specificity)과 재현성(reproducibility)이 우수함을 확인하였다. 확립된 real-time RT-PCR을 생물의약품 제조공정 검증에 적용할 수 있는지 확인하기 위하여 인위적으로 Reo-3를 오염시킨 CHO 세포에서 Reo-3 검출 시험을 실시한 결과 Reo-3를 감염시킨 CHO 세포와 세포배양 상청액에서 Reo-3를 정략적으로 검출할 수 있었다. 또한 바이러스필터 공정에서 Reo-3제거 효과를 감염역가 시험법과 비교 검증한 결과 더 빠른 시간에 동일한 결과를 얻을 수 있었다. 위와 같은 결과에서 확립된 Reo-3 real-time RT-PCR 시험법은 생물의약품 안전성 보증을 위한 세포주 검증, 생물의 약품 생산 공정 검증, 바이러스 제거 공정 검증 등에서 감염 역가 시험법을 대신할 수 있는 신속하고, 특이성과 민감성이 우수한 시험법임을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1450-1456
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• 2010

Accurate and rapid diagnosis of Pandemic Influenza A/H1N1 2009 virus (H1N1 2009) infection is important for the prevention and control of influenza epidemics and the timely initiation of antiviral treatment. This study was conducted to evaluate the performance of several diagnostic tools for the detection of H1N1 2009. Flocked nasopharyngeal swabs were collected from 254 outpatients of suspected H1N1 2009 during October 2009. This study analyzed the performances of the RealTime Ready Inf A/H1N1 Detection Set (Roche), Influenza A (H1N1) Real-Time Detection Kit (Bionote), Seeplex Influenza A/B OneStep Typing Set [Seeplex Reverse Transcriptase PCR (RT-PCR)], BinaxNow Influenza A & B Test Kit [Binax Rapid Antigen Test (RAT)], and SD BIOLINE Influenza Ag kit (SD RAT). Roche and Bionote real-time RT-PCR showed identical results for the H1N1 2009 hemagglutinin gene. Compared with real-time RT-PCR, the sensitivities and specificities were 83.7% and 100% for Seeplex RT-PCR, 64.5% and 94.7% for Binax RAT, and 69.5% and 100% for SD RAT. The sensitivities of Seeplex RT-PCR, Binax RAT, and SD RAT in patients aged over 21 years were 73.7%, 47.4%, and 57.9%, respectively. The sensitivities of Seeplex RT-PCR, Binax RAT, and SD RAT on the day of initial symptoms were mostly lower (68.8%, 56.3%, and 31.3%, respectively). In conclusion, multiplex RT-PCR and RAT for the detection of H1N1 2009 were significantly less sensitive than real-time RT-PCR. Moreover, a negative RAT may require more sensitive confirmatory assays, because it cannot be ruled out from influenza infection.