scholarly journals Sequence and primer independent stochastic heterogeneity in PCR amplification efficiency revealed by single molecule barcoding

2014 ◽  
Author(s):  
Katharine Best ◽  
Theres Oakes ◽  
James M Heather ◽  
John Shawe-Taylor ◽  
Benny Chain

The polymerase chain reaction (PCR) is one of the most widely used techniques in molecular biology. In combination with High Throughput Sequencing (HTS), PCR is widely used to quantify transcript abundance for RNA-seq and especially in the context of analysis of T cell and B cell receptor repertoires. In this study, we combine molecular DNA barcoding with HTS to quantify PCR output from individual target molecules. Our results demonstrate that the PCR process exhibits very significant unexpected heterogeneity, which is independent of the sequence of the primers or target, and independent of bulk experimental conditions. The mechanistic origin of this heterogeneity is not clear, but simulations suggest that it must derive from inherited differences between different DNA molecules within the reaction. The results illustrate that single molecule barcoding is important in order to derive reproducible quantitative results from any protocol which combines PCR with HTS.

Author(s):  
E.V. Korneenko ◽  
◽  
А.E. Samoilov ◽  
I.V. Artyushin ◽  
M.V. Safonova ◽  
...  

In our study we analyzed viral RNA in bat fecal samples from Moscow region (Zvenigorod district) collected in 2015. To detect various virus families and genera in bat fecal samples we used PCR amplification of viral genome fragments, followed by high-throughput sequencing. Blastn search of unassembled reads revealed the presence of viruses from families Astroviridae, Coronaviridae and Herpesviridae. Assembly using SPAdes 3.14 yields contigs of length 460–530 b.p. which correspond to genome fragments of Coronaviridae and Astroviridae. The taxonomy of coronaviruses has been determined to the genus level. We also showed that one bat can be a reservoir of several virus genuses. Thus, the bats in the Moscow region were confirmed as reservoir hosts for potentially zoonotic viruses.


2020 ◽  
Vol 4 (18) ◽  
pp. 4474-4482 ◽  
Author(s):  
Wen-Kai Weng ◽  
Sally Arai ◽  
Andrew Rezvani ◽  
Laura Johnston ◽  
Robert Lowsky ◽  
...  

Abstract The majority of patients with refractory, advanced-stage mycosis fungoides (MF) or Sézary syndrome (SS) have a life expectancy of <5 years. Here, we report a phase 2 study of a novel nonmyeloablative allogeneic transplantation strategy tailored for this patient population. This study has completed the enrollment, and 35 patients (13 MF, 22 SS) have undergone transplant as planned. The majority (80%) of the patients had stage IV disease and received multiple previous systemic therapies. All patients had active disease at the time of conditioning using total skin electron beam therapy, total lymphoid irradiation, and antithymocyte globulin, and received allograft infusion as outpatients. Cyclosporine or tacrolimus and mycophenolate mofetil were used for graft-versus-host disease (GVHD) prophylaxis. Patients tolerated the transplant well, with 1- and 2-year nonrelapse mortality of 3% and 14%, respectively. The day +180 cumulative incidence of grade 2 to 4 acute GVHD was 16%, and the 2-year incidence of moderate/severe chronic GVHD was 32%. With a median posttransplant follow-up of 5.4 years, the 2-, 3-, and 5-year overall survival rates were 68%, 62%, and 56%. Using high-throughput sequencing of the T-cell receptor for minimal residual disease monitoring, we observed that 43% achieved molecular remission, which was associated with a lower incidence of disease progression or relapse (9% vs 87%; P = .02). Our study also showed that patients who were aged ≥65 years at the time of allotransplant had similar clinical outcomes compared with younger patients. Thus, we have developed an alternative and potentially curative nonmyeloablative allogeneic transplant regimen for patients with advanced stage MF/SS. This trial was registered at www.clinicaltrials.gov as #NCT00896493.


2015 ◽  
Vol 61 (1) ◽  
pp. 145-153 ◽  
Author(s):  
Jared S Farrar ◽  
Carl T Wittwer

Abstract BACKGROUND PCR is a key technology in molecular biology and diagnostics that typically amplifies and quantifies specific DNA fragments in about an hour. However, the kinetic limits of PCR are unknown. METHODS We developed prototype instruments to temperature cycle 1- to 5-μL samples in 0.4–2.0 s at annealing/extension temperatures of 62 °C–76 °C and denaturation temperatures of 85 °C–92 °C. Primer and polymerase concentrations were increased 10- to 20-fold above typical concentrations to match the kinetics of primer annealing and polymerase extension to the faster temperature cycling. We assessed analytical specificity and yield on agarose gels and by high-resolution melting analysis. Amplification efficiency and analytical sensitivity were demonstrated by real-time optical monitoring. RESULTS Using single-copy genes from human genomic DNA, we amplified 45- to 102-bp targets in 15–60 s. Agarose gels showed bright single bands at the expected size, and high-resolution melting curves revealed single products without using any “hot start” technique. Amplification efficiencies were 91.7%–95.8% by use of 0.8- to 1.9-s cycles with single-molecule sensitivity. A 60-bp genomic target was amplified in 14.7 s by use of 35 cycles. CONCLUSIONS The time required for PCR is inversely related to the concentration of critical reactants. By increasing primer and polymerase concentrations 10- to 20-fold with temperature cycles of 0.4–2.0 s, efficient (>90%), specific, high-yield PCR from human DNA is possible in <15 s. Extreme PCR demonstrates the feasibility of while-you-wait testing for infectious disease, forensics, and any application where immediate results may be critical.


2016 ◽  
Vol 27 (22) ◽  
pp. 3627-3636 ◽  
Author(s):  
Sophie V. Pageon ◽  
Philip R. Nicovich ◽  
Mahdie Mollazade ◽  
Thibault Tabarin ◽  
Katharina Gaus

Advances in fluorescence microscopy are providing increasing evidence that the spatial organization of proteins in cell membranes may facilitate signal initiation and integration for appropriate cellular responses. Our understanding of how changes in spatial organization are linked to function has been hampered by the inability to directly measure signaling activity or protein association at the level of individual proteins in intact cells. Here we solve this measurement challenge by developing Clus-DoC, an analysis strategy that quantifies both the spatial distribution of a protein and its colocalization status. We apply this approach to the triggering of the T-cell receptor during T-cell activation, as well as to the functionality of focal adhesions in fibroblasts, thereby demonstrating an experimental and analytical workflow that can be used to quantify signaling activity and protein colocalization at the level of individual proteins.


2017 ◽  
Vol 137 (6) ◽  
pp. e131-e138 ◽  
Author(s):  
Tiago R. Matos ◽  
Menno A. de Rie ◽  
Marcel B.M. Teunissen

Author(s):  
Yachao Qu ◽  
Yong Huang ◽  
Di Liu ◽  
Yinuo Huang ◽  
Zhiyi Zhang ◽  
...  

T lymphocytes are the most important immune cells that affect both the development and treatment of hepatitis B. We used high-throughput sequencing to determine the diversity in the V and J regions of the TCRβchain in 4 chronic hepatitis B patients before and after HBeAg seroconversion. Here, we demonstrate that the 4 patients expressedVβ12-4 at the highest frequencies of 10.6%, 9.2%, 17.5%, and 7.5%, andVβ28was the second most common, with frequencies of 7.8%, 6.7%, 5.3%, and 10.9%, respectively. No significant changes were observed following seroconversion. With regard to the Jβgene, Jβ2-1 was the most commonly expressed in the 4 patients at frequencies of 5.8%, 6.5%, 11.3%, and 7.3%, respectively. Analysis of the V-J region genes revealed several differences, including significant increases in the expression levels of V7-2-01-J2-1, V12-4-J1-1, and V28-1-J1-5 and a decrease in that of V19-01-J2-3. These results illustrate the presence of biased TCRVβand Jβgene expression in the chronic hepatitis B patients. TRBVβ12-4,Vβ28, Jβ2-1, V7-2-01-J2-1, V12-4-J1-1, and V28-1-J1-5 may be associated with the development and treatment of CHB.


2021 ◽  
Author(s):  
Brian P. Anton ◽  
Alexey Fomenkov ◽  
Victoria Wu ◽  
Richard J. Roberts

ABSTRACTSingle-molecule Real-Time (SMRT) sequencing can easily identify sites of N6-methyladenine and N4-methylcytosine within DNA sequences, but similar identification of 5-methylcytosine sites is not as straightforward. In prokaryotic DNA, methylation typically occurs within specific sequence contexts, or motifs, that are a property of the methyltransferases that “write” these epigenetic marks. We present here a straightforward, cost-effective alternative to both SMRT and bisulfite sequencing for the determination of prokaryotic 5-methylcytosine methylation motifs. The method, called MFRE-Seq, relies on excision and isolation of fully methylated fragments of predictable size using MspJI-Family Restriction Enzymes (MFREs), which depend on the presence of 5-methylcytosine for cleavage. We demonstrate that MFRE-Seq is compatible with both Illumina and Ion Torrent sequencing platforms and requires only a digestion step and simple column purification of size-selected digest fragments prior to standard library preparation procedures. We applied MFRE-Seq to numerous bacterial and archaeal genomic DNA preparations and successfully confirmed known motifs and identified novel ones. This method should be a useful complement to existing methodologies for studying prokaryotic methylomes and characterizing the contributing methyltransferases.


Author(s):  
Dwiyitno Dwiyitno ◽  
Stefan Hoffman ◽  
Koen Parmentier ◽  
Chris Van Keer

Fish and seafood products has been commonly targeted for fraudulent activities. For that reason, authentication of fish and seafood products is important to protect consumers from fraudulent and adulteration practices, as well as to implement traceability regulation. From the viewpoint of food safety, authenticity is beneficial to protect public from serious food poisoning incidents, such as due to ingestion of toxic species. Since DNA based identification depends on the nucleic acid polymerase chain reaction (PCR), the quantity and quality/purity of DNA will contribute significantly to the species authentication. In the present study, different DNA extraction and purification methods (3 classical methods and one commercial kit) were compared to produce the better isolated DNA for PCR amplification. Additionally, different methods for the estimation of DNA concentration and purity which is essential for PCR amplification efficiency were also evaluated. The result showed that classical DNA extraction methods (based on TNES-Urea) yielded a higher amount of DNA (11.30-323.60 ng/g tissue) in comparison to commercial kit/Wizard Promega (5.70-83.45 ng/g tissue). Based on the purity of DNA extract (A260/280), classical DNA extraction method produced relatively similar on DNA quality to the commercial kit (1.79-2.12). Interestingly, all classical methods produced DNA with A260/280 ratio of more than 2.00 on the blue mussel, in contrast with commercial kit. The commercial kit also produced better quality of DNA compared to the classical methods, showing the higher efficiency in PCR amplification. NanoDrop is promising as cheap, robust and safe UV-spectrophotometer method for DNA quantification, as well as the purity evaluation.Keywords: seafood authenticity, DNA isolation, polymerase chain reaction, NanoDrop, Picogreen


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