scholarly journals An optimised direct lysis method for gene expression studies on low cell numbers

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Anh Viet-Phuong Le ◽  
Dexing Huang ◽  
Tony Blick ◽  
Erik W. Thompson ◽  
Alexander Dobrovic
Keyword(s):  
Gene Expression ◽  
Reverse Transcription ◽  
Single Cells ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Cost Effective ◽  
Breast Cancer Cell Lines ◽  
Cell Numbers ◽  
Ionic Detergent ◽  
Gene Expression Studies

Abstract There is increasing interest in gene expression analysis of either single cells or limited numbers of cells. One such application is the analysis of harvested circulating tumour cells (CTCs), which are often present in very low numbers. A highly efficient protocol for RNA extraction, which involves a minimal number of steps to avoid RNA loss, is essential for low input cell numbers. We compared several lysis solutions that enable reverse transcription (RT) to be performed directly on the cell lysate, offering a simple rapid approach to minimise RNA loss for RT. The lysis solutions were assessed by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in low cell numbers isolated from four breast cancer cell lines. We found that a lysis solution containing both the non-ionic detergent (IGEPAL CA-630, chemically equivalent to Nonidet P-40 or NP-40) and bovine serum albumin (BSA) gave the best RT-qPCR yield. This direct lysis to reverse transcription protocol outperformed a column-based extraction method using a commercial kit. This study demonstrates a simple, reliable, time- and cost-effective method that can be widely used in any situation where RNA needs to be prepared from low to very low cell numbers.

scholarly journals THE STUDY OF PROKARYOTIC GENE EXPRESSION

2018 ◽  
Vol 3 (2) ◽  
pp. 40-52
Author(s):  
Mihail Yu. Minaev ◽  
Anzhelika A. Makhova
Keyword(s):  
Gene Expression ◽  
Real Time ◽  
Reverse Transcription ◽  
Conflict Of Interest ◽  
Genomic Dna ◽  
Molecular Mechanisms ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Aeromonas Salmonicida ◽  
High Background

One of the methods to evaluate the level of gene expression is a real-time quantitative polymerase chain reaction (qPCR). Interest in the study of molecular mechanisms of gene expression and its evaluation in prokaryotes is due to the lack of research on this issue and a number of methodological problems. The paper presents a study of gene expression mechanism in prokaryotes evidence from Aeromonas salmonicida AS1 gyrase B and collagenase genes. As a result of the research, Random primer and oligo (dT) primer (two 3’-terminal nucleotides of the primer complementary to stop codon nucleotides of the transcribed DNA sequence) with anchor and adapter of our own design were tested, which are used in the reaction of reverse transcription. The use of oligo (dT) primer became possible only after polyadenylation of extracted RNA using special poly-A polymerase kit. It is determined that the developed protocol of reverse transcription (RT) using oligo (dT) primer and adapter with certain sequence on its 5’-terminus designed for further annealing of the reverse primer during real-time PCR along with preliminary polyadenylation of RNA excludes specific amplification of the background genomic DNA. This technique may be applied in evaluating the expression level of low-expression genes when high background genomic DNA content is found in the RNA sample, e.g. at the end of logarithmic growth of prokaryotic cells.ContributionAll authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. Minaev M. Yu. developed scientific and methodological approaches to work, determined the scope of research, analyzed the data obtained, performed the narrative and corrected it in final. Makhova A.A. selected research objects, carried out RNA extraction, reverse transcription and PCR analysis, performed the narrative part. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.Conflict of interestThe authors declare no conflict of interest.

scholarly journals Development and validation of a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of ZIKV in patient samples from Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Severino Jefferson Ribeiro da Silva ◽  
Keith Pardee ◽  
Udeni B. R. Balasuriya ◽  
Lindomar Pena
Keyword(s):  
Reverse Transcription ◽  
Rapid Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Serum Samples ◽  
Low Resource ◽  
Loop Mediated Isothermal Amplification ◽  
One Step

AbstractWe have previously developed and validated a one-step assay based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid detection of the Zika virus (ZIKV) from mosquito samples. Patient diagnosis of ZIKV is currently carried out in centralized laboratories using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR), which, while the gold standard molecular method, has several drawbacks for use in remote and low-resource settings, such as high cost and the need of specialized equipment. Point-of-care (POC) diagnostic platforms have the potential to overcome these limitations, especially in low-resource countries where ZIKV is endemic. With this in mind, here we optimized and validated our RT-LAMP assay for rapid detection of ZIKV from patient samples. We found that the assay detected ZIKV from diverse sample types (serum, urine, saliva, and semen) in as little as 20 min, without RNA extraction. The RT-LAMP assay was highly specific and up to 100 times more sensitive than RT-qPCR. We then validated the assay using 100 patient serum samples collected from suspected cases of arbovirus infection in the state of Pernambuco, which was at the epicenter of the last Zika epidemic. Analysis of the results, in comparison to RT-qPCR, found that the ZIKV RT-LAMP assay provided sensitivity of 100%, specificity of 93.75%, and an overall accuracy of 95.00%. Taken together, the RT-LAMP assay provides a straightforward and inexpensive alternative for the diagnosis of ZIKV from patients and has the potential to increase diagnostic capacity in ZIKV-affected areas, particularly in low and middle-income countries.

scholarly journals Robust Saliva-Based RNA Extraction-Free One-Step Nucleic Acid Amplification Test for Mass SARS-CoV-2 Monitoring

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6617
Author(s):  
Eva Rajh ◽  
Tina Šket ◽  
Arne Praznik ◽  
Petra Sušjan ◽  
Alenka Šmid ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Reverse Transcription ◽  
Screening Program ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Diagnostic Sensitivity ◽  
Nucleic Acid Amplification ◽  
Nasopharyngeal Swab ◽  
Viral Spread ◽  
One Step

Early diagnosis with rapid detection of the virus plays a key role in preventing the spread of infection and in treating patients effectively. In order to address the need for a straightforward detection of SARS-CoV-2 infection and assessment of viral spread, we developed rapid, sensitive, extraction-free one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP) tests for detecting SARS-CoV-2 in saliva. We analyzed over 700 matched pairs of saliva and nasopharyngeal swab (NSB) specimens from asymptomatic and symptomatic individuals. Saliva, as either an oral cavity swab or passive drool, was collected in an RNA stabilization buffer. The stabilized saliva specimens were heat-treated and directly analyzed without RNA extraction. The diagnostic sensitivity of saliva-based RT-qPCR was at least 95% in individuals with subclinical infection and outperformed RT-LAMP, which had at least 70% sensitivity when compared to NSBs analyzed with a clinical RT-qPCR test. The diagnostic sensitivity for passive drool saliva was higher than that of oral cavity swab specimens (95% and 87%, respectively). A rapid, sensitive one-step extraction-free RT-qPCR test for detecting SARS-CoV-2 in passive drool saliva is operationally simple and can be easily implemented using existing testing sites, thus allowing high-throughput, rapid, and repeated testing of large populations. Furthermore, saliva testing is adequate to detect individuals in an asymptomatic screening program and can help improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

scholarly journals Maternal blood and amnionic oxytocin receptor gene expression and serum oxytocin levels in preterm birth: a case control study

2020 ◽  
Author(s):  
KUMARI ANUKRITI ◽  
KIRAN GULERIA ◽  
VIPIN TYAGI ◽  
AMITA SUNEJA ◽  
BASU DEV BANERJEE
Keyword(s):  
Gene Expression ◽  
Preterm Birth ◽  
Quantitative Polymerase Chain Reaction ◽  
Receptor Gene ◽  
Active Phase ◽  
Maternal Blood ◽  
Oxytocin Receptor ◽  
Maternal Serum ◽  
Oxytocin Receptor Gene ◽  
Gene Expression Studies

BACKGROUND: The oxytocin (OXT)-oxytocin receptor (OXTR) system provides promising candidate gene for studies of genetic contributions to prematurity. OBJECTIVE: Quantification and comparison of oxytocin receptor (OXTR) gene expression and serum OXT levels in the blood and amnion of women delivering preterm and evaluation of the correlation between OXTR gene expression in blood and amnion with serum OXT levels in them. METHODS: 70 pregnant women in spontaneous labor delivering vaginally preterm i.e < 37 weeks and equal number of matched controls delivering spontaneously at term (37-42 weeks) were recruited. Maternal serum OXT levels taken in active stage of labor (i.e 4 cm cervical dilatation) were quantified by ELISA. Gene expression studies in the maternal blood and amnion were done by using real time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The mean serum OXT level in PTL was 48.56 +- 6.97 pg/ml; significantly higher than in controls (43.00 +- 3.96 pg/ml), p<0.001. OXTR gene expression both in maternal blood (2.5 times) and amnion (3.5 times) were significantly higher in PTL. A significant positive correlation was observed between serum OXT levels and OXTR gene expression in amnion (r = -0.190, p = 0.025). CONCLUSIONS: The serum OXT levels and OXTR gene expression in amnion surge significantly in active phase of PTL. Thus, amnion probably links OXT-PTGs autocrine paracrine circuit to facilitate PTL. Future studies are needed to devise better OXTR receptor antagonists preferably acting on amnionic OXTRs to prevent PTL. KEYWORDS: Preterm birth, Preterm labor, Oxytocin, Oxytocin receptor, Placenta, Amnion

scholarly journals Selection and validation of reference genes for gene expression studies in Klebsiella pneumoniae using Reverse Transcription Quantitative real-time PCR

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ana Érika Inácio Gomes ◽  
Leonardo Prado Stuchi ◽  
Nathália Maria Gonçalves Siqueira ◽  
João Batista Henrique ◽  
Renato Vicentini ◽  
...  
Keyword(s):  
Gene Expression ◽  
Klebsiella Pneumoniae ◽  
Real Time ◽  
Reverse Transcription ◽  
Real Time Pcr ◽  
Reference Genes ◽  
Quantitative Real Time Pcr ◽  
Expression Studies ◽  
Gene Expression Studies

scholarly journals Rapid and Extraction-Free Detection of SARS-CoV-2 from Saliva by Colorimetric Reverse-Transcription Loop-Mediated Isothermal Amplification

2020 ◽  
Author(s):  
Matthew A Lalli ◽  
Joshua S Langmade ◽  
Xuhua Chen ◽  
Catrina C Fronick ◽  
Christopher S Sawyer ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Quantitative Polymerase Chain Reaction ◽  
Rna Extraction ◽  
Lamp Assay ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Viral Detection ◽  
Loop Mediated Isothermal Amplification

Abstract Background Rapid, reliable, and widespread testing is required to curtail the ongoing COVID-19 pandemic. Current gold-standard nucleic acid tests are hampered by supply shortages in critical reagents including nasal swabs, RNA extraction kits, personal protective equipment, instrumentation, and labor. Methods To overcome these challenges, we developed a rapid colorimetric assay using reverse-transcription loop-mediated isothermal amplification (RT-LAMP) optimized on human saliva samples without an RNA purification step. We describe the optimization of saliva pretreatment protocols to enable analytically sensitive viral detection by RT-LAMP. We optimized the RT-LAMP reaction conditions and implemented high-throughput unbiased methods for assay interpretation. We tested whether saliva pretreatment could also enable viral detection by conventional reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Finally, we validated these assays on clinical samples. Results The optimized saliva pretreatment protocol enabled analytically sensitive extraction-free detection of SARS-CoV-2 from saliva by colorimetric RT-LAMP or RT-qPCR. In simulated samples, the optimized RT-LAMP assay had a limit of detection of 59 (95% confidence interval: 44–104) particle copies per reaction. We highlighted the flexibility of LAMP assay implementation using 3 readouts: naked-eye colorimetry, spectrophotometry, and real-time fluorescence. In a set of 30 clinical saliva samples, colorimetric RT-LAMP and RT-qPCR assays performed directly on pretreated saliva samples without RNA extraction had accuracies greater than 90%. Conclusions Rapid and extraction-free detection of SARS-CoV-2 from saliva by colorimetric RT-LAMP is a simple, sensitive, and cost-effective approach with broad potential to expand diagnostic testing for the virus causing COVID-19.

scholarly journals Bacterial Internalization, Localization, and Effectors Shape the Epithelial Immune Response during Shigella flexneri Infection

2015 ◽  
Vol 83 (9) ◽  
pp. 3624-3637 ◽  
Author(s):  
Juliane Lippmann ◽  
Frederik Gwinner ◽  
Camille Rey ◽  
Uyanga Tamir ◽  
Helen K. W. Law ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Single Cell Analysis ◽  
Single Cells ◽  
Shigella Flexneri ◽  
Host Responses ◽  
Host Immune System ◽  
Content Type ◽  
Infected Cells ◽  
Gene Expression Studies

Intracellular pathogens are differentially sensed by the compartmentalized host immune system. Nevertheless, gene expression studies of infected cells commonly average the immune responses, neglecting the precise pathogen localization. To overcome this limitation, we dissected the transcriptional immune response toShigella flexneriacross different infection stages in bulk and single cells. This identified six distinct transcriptional profiles characterizing the dynamic, multilayered host response in both bystander and infected cells. These profiles were regulated by external and internal danger signals, as well as whether bacteria were membrane bound or cytosolic. We found that bacterial internalization triggers a complex, effector-independent response in bystander cells, possibly to compensate for the undermined host gene expression in infected cells caused by bacterial effectors, particularly OspF. Single-cell analysis revealed an important bacterial strategy to subvert host responses in infected cells, demonstrating that OspF disrupts concomitant gene expression of proinflammatory, apoptosis, and stress pathways within cells. This study points to novel mechanisms through which bacterial internalization, localization, and injected effectors orchestrate immune response transcriptional signatures.

scholarly journals Integrated RNA extraction and RT-PCR for semi-quantitative gene expression studies on a microfluidic device

2013 ◽  
Vol 93 (8) ◽  
pp. 961-966 ◽  
Author(s):  
Kirsty J Shaw ◽  
Elizabeth M Hughes ◽  
Charlotte E Dyer ◽  
John Greenman ◽  
Stephen J Haswell
Keyword(s):  
Gene Expression ◽  
Microfluidic Device ◽  
Rna Extraction ◽  
Rt Pcr ◽  
Quantitative Gene Expression ◽  
Expression Studies ◽  
Gene Expression Studies

Identification of reference genes for gene expression studies during seed germination and seedling establishment in Ricinus communis L.

2014 ◽  
Vol 24 (4) ◽  
pp. 341-352 ◽  
Author(s):  
Paulo R. Ribeiro ◽  
Bas J. W. Dekkers ◽  
Luzimar G. Fernandez ◽  
Renato D. de Castro ◽  
Wilco Ligterink ◽  
...  
Keyword(s):  
Gene Expression ◽  
Seed Germination ◽  
Reference Genes ◽  
Target Genes ◽  
Ricinus Communis ◽  
Quantitative Polymerase Chain Reaction ◽  
Optimal Combination ◽  
Expression Levels ◽  
Gene Expression Studies ◽  
Gene Expression Levels

AbstractReverse transcription-quantitative polymerase chain reaction (RT-qPCR) is an important technology to analyse gene expression levels during plant development or in response to different treatments. An important requirement to measure gene expression levels accurately is a properly validated set of reference genes. In this context, we analysed the potential use of 17 candidate reference genes across a diverse set of samples, including several tissues, different stages and environmental conditions, encompassing seed germination and seedling growth in Ricinus communis L. These genes were tested by RT-qPCR and ranked according to the stability of their expression using two different approaches: GeNorm and NormFinder. GeNorm and Normfinder indicated that ACT, POB and PP2AA1 comprise the optimal combination for normalization of gene expression data in inter-tissue (heterogeneous sample panel) studies. We also describe the optimal combination of reference genes for a subset of root, endosperm and cotyledon samples. In general, the most stable genes suggested by GeNorm are very consistent with those indicated by NormFinder, which highlights the strength of the selection of reference genes in our study. We also validated the selected reference genes by normalizing the expression levels of three target genes involved in energy metabolism with the reference genes suggested by GeNorm and NormFinder. The approach used in this study to identify stably expressed genes, and thus potential reference genes, was applied successfully for R. communis and it provides important guidelines for RT-qPCR studies in seeds and seedlings for other species (especially in those cases where extensive microarray data are not available).

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