scholarly journals NewIn SituCapture Quantitative (Real-Time) Reverse Transcription-PCR Method as an Alternative Approach for Determining Inactivation of Tulane Virus

2014 ◽  
Vol 80 (7) ◽  
pp. 2120-2124 ◽  
Author(s):  
Dapeng Wang ◽  
Shuxia Xu ◽  
David Yang ◽  
Glenn M. Young ◽  
Peng Tian

ABSTRACTHuman noroviruses (HuNoVs) are the major cause of epidemic nonbacterial gastroenteritis. Although quantitative (real-time) reverse transcription-PCR (qRT-PCR) is widely used for detecting HuNoVs, it only detects the presence of viral RNA and does not indicate viral infectivity. Human blood group antigens (HBGAs) have been identified as receptors/co-receptors for both HuNoVs and Tulane virus (TV) and are crucial for viral infection. We propose that viral infectivity can be evaluated with a molecular assay based on receptor-captured viruses. In this study, we employed TV as an HuNoV surrogate to validate the HBGA-based capture qRT-PCR method against the 50% tissue culture infectious dose (TCID50) method. We employed type B HBGA on an immuno-well module to concentrate TV, followed by amplification of the captured viral genome byin situqRT-PCR. We first demonstrated that thisin situcapture qRT-PCR (ISC-qRT-PCR) method could effectively concentrate and detect TV. We then treated TV under either partial or full inactivation conditions and measured the remaining infectivity by ISC-qRT-PCR and a tissue culture-based amplification method (TCID50). We found that the ISC-qRT-PCR method could be used to evaluate virus inactivation deriving from damage to the capsid and study interactions between the capsid and viral receptor. Heat, chlorine, and ethanol treatment primarily affect the capsid structure, which in turns affects the ability of the capsid to bind to viral receptors. Inactivation of the virus by these methods could be reflected by the ISC-qRT-PCR method and confirmed by TCID50assay. However, the loss of the infectivity caused by damage to the viral genome (such as that from UV irradiation) could not be effectively reflected by this method. Despite this limitation, the ISC-qRT-PCR provides an alternative approach to determine inactivation of Tulane virus. A particular advantage of the ISC-qRT-PCR method is that it is also a faster and easier method to effectively recover and detect the viruses, as there is no need to extract viral RNA or to transfer the captured virus from magnetic beads to PCR tubes for further amplification. Therefore, ISC-qRT-PCR can be easily adapted for use in automated systems for multiple samples.

1999 ◽  
Vol 37 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Deborah A. Buonagurio ◽  
John W. Coleman ◽  
Sai A. Patibandla ◽  
Bellur S. Prabhakar ◽  
Joanne M. Tatem

A multiplex reverse transcription-PCR method was optimized to monitor the duration of excretion of Sabin poliovirus strains in stools of vaccinees following administration of the first dose of the trivalent oral vaccine. The assay detected approximately 1 50% tissue culture infective dose of each poliovirus serotype spiked into cell culture media. Although PCR inhibitors were frequently encountered in the stool specimens, a 1:20 dilution of the extracted RNA was sufficient to obtain a positive PCR result. Analysis of 195 stool specimens collected from 26 vaccinees showed that poliovirus types 1, 2, and 3 were identified more frequently by PCR than by tissue culture isolation. The percentages of specimens positive by PCR for poliovirus types 1, 2, and 3 were 67.2, 82.6, and 53.8, respectively. In contrast, the culture method identified types 1, 2, and 3 virus in 55.4, 64.1, and 27.7% of the samples, respectively. Poliovirus type 2 excretion was detected by PCR in practically all of the oral poliovirus vaccine recipients for 4 to 8 weeks following vaccination. In contrast, excretion of type 1 and 3 viruses was more variable, with a range of 1 to 8 weeks. Shedding of type 3 virus ceased in ∼70% of vaccinees within a week after immunization. In addition to an enhanced sensitivity for the detection of poliovirus, this PCR method permits the direct characterization of virus in stool specimens without further passage in culture, which may select for genetic variants that may not accurately reflect the virus composition in the original specimen.


2008 ◽  
Vol 36 (3) ◽  
pp. 540-542 ◽  
Author(s):  
Carine Barreau ◽  
Elizabeth Benson ◽  
Helen White-Cooper

Post-meiotic transcription is widespread in mammalian spermatogenesis, but is generally believed to be absent from Drosophila spermatogenesis. Genes required during meiosis, in early spermatids or later in spermiogenesis are typically transcribed in primary spermatocytes in Drosophila. Their mRNAs are then stored in the cytoplasm until the protein product is needed. Recently, using in situ hybridization, we identified 17 Drosophila genes, collectively named ‘comets’ and ‘cups’, whose mRNAs are most abundant in, and localize to the distal ends of, elongating spermatids. Using a single-cyst quantitative RT–PCR (reverse transcription–PCR) assay, we confirmed this unusual expression pattern and conclusively demonstrate the existence of post-meiotic transcription in Drosophila spermatids. We found that transcription of comets and cups occurs just before protamines can be detected in spermatid nuclei.


2003 ◽  
Vol 69 (9) ◽  
pp. 5726-5730 ◽  
Author(s):  
M. Gray ◽  
B. Wawrik ◽  
J. Paul ◽  
E. Casper

ABSTRACT A real-time reverse transcription-PCR method targeting the rbcL gene was developed for the detection and quantitation of the Florida red tide organism, Karenia brevis. The assay was sensitive to less than 1 cell per reaction, did not detect rbcL from 38 nontarget taxa, and accurately quantitated K. brevis organisms in red tide samples from around Florida. These studies have resulted in a sensitive and specific method for K. brevis detection in the marine environment.


2021 ◽  
Author(s):  
Seyedeh Negin Shahcheraghi ◽  
Seyed Ataollah Sadat Shandiz ◽  
Bahareh Pakpour

Abstract In the current experimental work, silver chloride nanoparticles (AgClNPs) were fabricated using Onopordum acanthium L extract and their apoptotic and cytotoxicity properties on breast cancer MDA_MB232 and normal HEK293 cell lines were also evaluated. AgClNPs formation was determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) profile. Effect of fabricated AgClNPs on MDA_MB232 and HEK293 cells viability was performed using colorimetric MTT assay. Alterations in the mRNA expression levels of CAD and Bax genes in MDA-MB-232 cells were done using quantitative real-time reverse transcription-PCR (qRT-PCR) method. Subsequently, apoptotic properties were determined using flow cytometry and fluorescence microscopy studies. MTT results investigated that AgCLNPs have a significant dose-dependent lethal activity on MDA_MB232 compared to HEK293 cell lines. Quantitative real-time reverse transcription-PCR (qRT-PCR) results have also shown that AgCLNPs could up-regulate the apoptotic Bax and CAD gene expressions in the MDA_MB232 cells. Additionally, apoptotic assessment was performed by cell cycle analysis, annexin V/PI test, Hoescht 33258 dye, acridine orange and ethidium bromide (AO/EB) staining along with the detection of the reactive oxygen species (ROS) generation. Our results suggest that novel silver chloride nanoparticles fabricated by Onopordum acanthium L extract can display some promising cytotoxic properties through inducing apoptosis pathway.


1999 ◽  
Vol 65 (1) ◽  
pp. 322-326 ◽  
Author(s):  
Charlotte Arnal ◽  
Virginie Ferre-Aubineau ◽  
Berangere Mignotte ◽  
Berthe Marie Imbert-Marcille ◽  
Sylviane Billaudel

ABSTRACT To quantify hepatitis A virus (HAV) in experimentally contaminated mussels, we developed an internal standard RNA with a 7-nucleotide deletion for competitive reverse transcription (RT)-PCR. Deposited directly into the sample, this standard was used both as extraction control and as quantification tool. After coextraction and competitive RT-PCR, standard and wild-type products were detected by differential hybridization with specific probes and a DNA enzyme immunoassay. The quantifiable range with this reproducible method was 104 to 107 copies of HAV/gram or 400 to 106 50% tissue culture infective doses/ml.


2005 ◽  
Vol 109 (4) ◽  
pp. 365-379 ◽  
Author(s):  
Stephen A. Bustin ◽  
Reinhold Mueller

qRT-PCR (real-time reverse transcription-PCR) has become the benchmark for the detection and quantification of RNA targets and is being utilized increasingly in novel clinical diagnostic assays. Quantitative results obtained by this technology are not only more informative than qualitative data, but simplify assay standardization and quality management. qRT-PCR assays are most established for the detection of viral load and therapy monitoring, and the development of SARS (severe acute respiratory syndrome)-associated coronavirus qRT-PCR assays provide a textbook example of the value of this technology for clinical diagnostics. The widespread use of qRT-PCR assays for diagnosis and the detection of disease-specific prognostic markers in leukaemia patients provide further examples of their usefulness. Their value for the detection of disease-associated mRNA expressed by circulating tumour cells in patients with solid malignancies is far less apparent, and the clinical significance of results obtained from such tests remains unclear. This is because of conceptual reservations as well as technical limitations that can interfere with the diagnostic specificity of qRT-PCR assays. Therefore, although it is evident that qRT-PCR assay has become a useful and important technology in the clinical diagnostic laboratory, it must be used appropriately and it is essential to be aware of its limitations if it is to fulfil its potential.


1998 ◽  
Vol 3 (1) ◽  
pp. 1-4
Author(s):  
Laura Bombelli ◽  
Luisa Doneda ◽  
Chiara Tonelli ◽  
Silvana Dolfini

2000 ◽  
Vol 66 (5) ◽  
pp. 1796-1800 ◽  
Author(s):  
Marianne Lange ◽  
Tim Tolker-Nielsen ◽  
Søren Molin ◽  
Birgitte K. Ahring

ABSTRACT An in situ reverse transcription-PCR protocol for detecting specific mRNA in Methanosarcina mazei S-6 is described. This method allowed us to detect heat shock-induced increases in the intracellular levels of the transcript of the universal stress genednaK. The cell walls of paraformaldehyde-fixed cells were permeabilized by a thermal cycling procedure or by lysozyme treatment, and the cellular DNA was removed with DNase. The cells were subjected to a seminested reverse transcription-PCR protocol in which a digoxigenin-labeled primer was used. Detection of the reporter molecule was based on the 2-hydroxy-3-naphtoic acid-2′-phenylanilide phosphate–Fast Red detection system and binding of anti-digoxigenin–alkaline phosphatase conjugate. Fluorescence in permeabilized cells increased after a heat shock compared to fluorescence in non-heat-shocked cells, and the increase corresponded to an increase in the level of the dnaK transcript.


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