Human genetic studies are using an increasing number of biobanked DNA samples, which require consistent measurements of DNA quantity and purity between multicenters or multilaboratories. In an attempt to standardize DNA quantitation protocols, a DNA quantitation project was performed, in which 16 technicians from 11 laboratories participated in measuring optical density (A260, A280, A230) of multiple DNA samples (N = 35) of known concentrations. We analyzed variations in the measurement of DNA quantity and purity and found that the mean interoperator coefficients of variation percentage for A260, A260/A280, and A260/A230 values among individuals were 21.9%, 7.4%, and 24.7%, respectively. In contrast, the mean intra-operator coefficients of variation percentage for A260, A260/A280, and A260/A230 values were 9.9%, 1.7%, and 8.3%, respectively. The variability in A260/A230 determination was much more sensitive to the method of DNA quantitation and the technical skill of the individual than those of A260 and A260/A280. In addition, a concentration of DNA of >100 ng/μL was found to reduce the variability of DNA quantity (A260) and purity (A260/A280 and A260/A230 ratios) indexes. This work emphasizes the need for standardization of DNA quantitation protocols for multicenter DNA work, as well as the importance of training and education of technicians at these centers.
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http://dx.doi.org/10.1089/bio.2010.0016 | DOI Listing |
Front Cell Dev Biol
December 2024
A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
Mitochondria are semi-autonomous organelles containing their own DNA (mtDNA), which is replicated independently of nuclear DNA (nDNA). While cell cycle arrest halts nDNA replication, mtDNA replication continues. In , flow cytometry enables semi-quantitative estimation of mtDNA levels by measuring the difference in signals between cells lacking mtDNA and those containing mtDNA.
View Article and Find Full Text PDFSLAS Technol
December 2024
Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI 02912, USA. Electronic address:
Automated liquid handlers are fundamental in modern life science laboratories, yet their high costs and large footprints often limit accessibility for smaller labs. This study presents an innovative approach to decentralizing a liquid handling system by converting a low-cost 3D printer into a customizable and accurate liquid handler. The Personal Automated Liquid Handler (PALH) system, costing ∼$400, incorporates a single-channel pipet, custom 3D-printed components, and open-source software for personalized workflows, allowing researchers to build and modify the system for specific experimental needs.
View Article and Find Full Text PDFWater Res
December 2024
Key Laboratory of Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China; State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China. Electronic address:
As a byproduct of shale gas extraction, flowback water (FW) is produced in large quantities globally. Due to the unique interactions between pollutants and microorganisms, FW always harbor multiple antibiotic resistance genes (ARGs) that have been confirmed in our previous findings, potentially serving as a point source for ARGs released into the environment. However, whether ARGs in FW can disseminate or integrate into the environmental resistome remains unclear.
View Article and Find Full Text PDFMethods Protoc
December 2024
General Diagnostic Department, Istituto Zooprofilattico Sperimentale del Lazio e della Toscana "M. Aleandri", 00178 Rome, Italy.
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View Article and Find Full Text PDFMethods Protoc
December 2024
Department of Pathology, Herlev University Hospital, 2730 Herlev, Denmark.
High-quality RNA is crucial in clinical diagnostics and precision medicine. Formalin-fixed and paraffin-embedded (FFPE) tissues pose a challenge due to nucleic acid fragmentation and crosslinking. In this pilot study, various commercially available techniques for extracting RNA from small FFPE samples were compared.
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