BioTechniques

The current detection methods for glycoRNAs include metabolic labeling of living cells or animals and rPAL that directly detects native glycoRNAs by periodate oxidation and aldehyde ligation. Both of them have some limitations. Here we reported a simple and rapid detection of native glycoRNAs by using lectins. The method involves in several simple procedures: isolation of total RNA, northern blotting and detection with lectins. The advantages of this method include high sensitivity, very simple procedures and broader applications. We used this method detecting glycoRNA expression in the RNA samples from different species. We also detect the glycoRNA expression across the varieties of mouse and human tissues and compared with other detection methods. We are in the first to detect free glycoRNAs in the varieties of human biofluids. Overall, this simple and rapid method will provide a new tool for study of glycoRNA biology and clinical diagnosis in future.

Quantitative polymerase chain reaction (qPCR) is limited in measuring absolute nucleic acid copy numbers due to the inherent variability of calibrators. Here, we introduce the Quantal PCR (quPCR), a novel method that eliminates the need for calibrators by defining an intrinsic quantal unit derived from the thermodynamic and kinetic properties of the replication system. This approach first determines amplification efficiency at high template concentrations, which is then used as the replication probability to construct quantification cycle (Cq) distribution profiles. These profiles are compared with those from limiting dilution PCR to derive the Cq value for the minimal quantal-replication unit ("quCq"), enabling calculation of the sample copy number. Validation using a dual-target DNA template showed near-identical copy numbers using two distinct target-specific replication systems. Thus, quPCR represents a new method for absolute nucleic acid quantification at the single-molecule level, offering a calibrator-free alternative for absolute quantification.

We have developed and validated an innovative protocol for analyzing catalase activity in microvolumes using the NanoDrop spectrophotometer. This method offers a solution to the challenge of working with limited biological samples and provides an efficient alternative to conventional protocols that require larger sample volumes. Unlike typical microplate assays that aim to increase throughput or reduce costs, our protocol was developed specifically for scenarios where biological material is scarce, such as studies with small organisms like Panagrellus redivivus and Caenorhabditis elegans, as well as with certain tissues of Drosophila and other small organisms. A key advantage of the method described here is the ability to accurately measure catalase activity with as little as 2 L of sample, making it ideal for studies where sample availability is extremely limited. The results show that the protocol effectively assesses catalase efficiency and reflects the physiological and metabolic properties of the tissues studied. Inhibitors and denaturants were used to ensure specificity of catalase measurements and the method was optimized for minimal reagent consumption. This approach greatly expands the research possibilities on enzymatic activity in reduced biological models, especially in contexts where small samples are critical, such as limited tissue collections or small organisms Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/687299v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@9334fborg.highwire.dtl.DTLVardef@7b66baorg.highwire.dtl.DTLVardef@1957c28org.highwire.dtl.DTLVardef@10a44a7_HPS_FORMAT_FIGEXP M_FIG C_FIG

Advancements in sequencing technology have led to the emergence of diverse types of regulatory RNAs. Differential transcript levels regulate cellular processes and influence disease severity. Identifying these variations through reliable methods is crucial for understanding their regulatory roles and disease mechanisms. Northern blotting, which used to be considered the gold standard for differential expression analysis, poses challenges due to various limitations associated with RNA quality, integrity, radioactivity, reagents, and the expenses associated with it. In this study, we employed a biotin-based Northern blotting approach, BiNoB, which offers advantages over traditional methods. In this study, we comprehensively targeted various RNA types, making this technique a versatile tool for RNA detection. Additionally, we conducted a comparison between 3-end labeled probes, which were labeled in-house, and 5-end labeled probes, which were commercially obtained. Remarkably, the results revealed significantly increased sensitivity with 3-end labeled probes. Furthermore, we prepared an in-house buffer and compared its performance with the commercially available ULTRAhyb buffer, which exhibited comparable sensitivity, indicating that the in-house buffer is a cost-effective alternative. Intriguingly, our findings showed that as little as 1{micro}g of total RNA proved to be adequate for the detection of small RNAs like tRNAs and their derived fragments.

Precision-cut lung slices (PCLS) have emerged as a powerful tool for studying the biology of viable human lung tissue. However, the presence of agarose impurities compromises RNA yield and integrity during the extraction process. We tested whether using an alternative Plant kit RNA extraction method to wash agarose impurities or pre-dissolving agarose from PCLS implementing a dissolving buffer for routine RNA isolation in gel-electrophoresis would improve RNA quantity, quality, and integrity. Our results show that RNA quantity and integrity are highly compromised when using a conventional method of RNA extraction. The plant kit and dissolution of agarose increased the RNA quantity to 0.42{+/-}0.11 and 0.65{+/-}0.17 {micro}g/PCLS (measured by the Qubit) and integrity number to 6.60{+/-}0.59 and 9.13{+/-}0.39 (measured by the Bioanalyzer), respectively. The presence of impurities in conventional and Plant kit extractions misled to an overestimation of the RNA quantity and quality using the NanoDrop. The Plant kit and agarose dissolution showed a significant transcript integrity increase in GUSB (p<0.0001) and COL1A1 (p<0.05) expression, validating these methods over conventional extraction. We encourage laboratories applying PCLS experimentation to implement alternative methods to remove agarose impurities during RNA extraction, as well as to rely on sensitive quantitative techniques, such as the Qubit and Bioanalyzer, for RNA quantification and integrity measurements.

Quantitative PCR is frequently used to measure average telomere length (TL) relative to the TL of a reference DNA sample of the investigators choosing. This makes comparisons of TLs across studies and laboratories difficult. Here we demonstrate that a single synthetic single-stranded dual-template oligonucleotide (DTO) containing both a telomere repeat sequence (T) and a segment of the human beta-globin (HBB) single copy gene (S) can be used as a universal reference standard for monochrome multiplex quantitative PCR (MMqPCR) measurements of average TL using SYBR Green I as the only fluorescent reporter dye. A set of twelve concentrations of the DTO is prepared by serial 3-fold dilutions, to a lowest concentration of ~20 copies per l. The 5 highest concentrations are used for the T standard curve, and the 5 lowest concentrations are used for the S standard curve. For each reaction 5 l containing approximately 3 ng of genomic DNA (or one of the DTO dilutions) is mixed with 5 l of a 2x MasterMix containing the primers for T and S amplification, and MMqPCR is performed. The design of the primers and thermal cycling profile allows all T amplification signals to be collected before exponential amplification of the S signal begins. Exponential amplification from S is then carried out in a temperature range that keeps the telomere product fully melted and therefore unable to influence the S amplification signal. The T value for each DNA sample is the Standard Curve DTO dilution that contains the same number of copies of the telomere sequence as the experimental sample, and the S value is the DTO dilution that contains the same number of copies of the single copy gene sequence as the experimental sample. Dividing the first dilution by the second dilution yields an absolute T/S ratio, since it is expressed relative to the fixed 1:1 T/S ratio that is built into the DTO by design. Absolute T/S ratios for average TL in 48 human DNA samples determined by this method correlated strongly with mean Terminal Restriction Fragment (mTRF) lengths for the same DNA samples determined by the Southern Blot method (R-squared = 0.801). This DTO and the accompanying protocol may facilitate the standardization of average telomere length measurements and analyses across laboratories.

BackgroundDNA polymerase activity assays are required for enzyme quality control in biotechnology and diagnostics, but standard methods rely on specialist reagents, radioactivity and other hazardous materials, or real-time PCR instruments that are not widely accessible in resource-limited settings. This constrains local production of high quality, validated reagents and increases dependence on imported enzymes. MethodsBased on experiences derived from partnerships with scientists in several low and middle-income countries (LMICs) and stakeholder consultations, we adapted a commercial EvaGreen-based fluorometric DNA polymerase activity assay for isothermal operation using minimal equipment. Assay conditions were optimized using Design of Experiments (DOE) methodology, varying temperature, reaction volume, and MgCl2 concentration. To address reagent cost and supply-chain constraints, we developed detailed protocols for in-house synthesis of the off-patent AOAO-12 DNA dye (sold commercially as EvaGreen) and generation of single-stranded DNA templates via asymmetric PCR. ResultsOptimized isothermal assay conditions (40{degrees}C, 7.75 mM MgCl2) reliably quantified activity across multiple DNA polymerase families. In-house synthesized AOAO-12 dye exhibited comparable DNA-binding performance to commercial alternatives (R{superscript 2} = 0.95), reducing costs by more than an order of magnitude when normalized to working concentrations, enabling assay costs of approximately {pound}0.001 per reaction. The assay is effective across multiple polymerases (Bst-LF, OpenVent, Taq, Q5) and is compatible with both plate readers and qByte, a low-cost, open-source fluorometric device. ConclusionsThis stakeholder-informed assay provides an accessible, cost-effective solution for DNA polymerase quality control in resource-limited settings. The combination of optimized commercial protocols and in-house reagent synthesis offers flexibility for different resource contexts, potentially improving access to molecular biology tools globally.

We describe our efforts at developing a one-step quantitative reverse-transcription (qRT)-PCR protocol to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA directly from saliva samples, without RNA purification. We find that both heat and the presence of saliva impairs the ability to detect synthetic SARS-CoV-2 RNA. Buffer composition (for saliva dilution) was also crucial to effective PCR detection. Using the SG2 primer pair, designed by Sigma-Aldrich, we were able to detect the equivalent of 1.7x106 viral copies per mL of saliva after heat inactivation; approximately equivalent to the median viral load in symptomatic patients. This would make our assay potentially useful for rapid detection of high-shedding infected individuals. We also provide a comparison of the PCR efficiency and specificity, which varied considerably, across 9 reported primer pairs for SARS-CoV-2 detection. Primer pairs SG2 and CCDC-N showed highest specificity and PCR efficiency. Finally, we provide an alternate primer pair to use as a positive control for human RNA detection in SARS-CoV-2 assays, as we found that the widely used US CDC primers (targeting human RPP30) do not span an exon-exon junction and therefore does not provide an adequate control for the reverse transcription reaction.

DNA extraction is an essential routine procedure for downstream applications in genetics and molecular biology. Since DNA was extracted for the first time, countless protocols have been developed yielding excellent results; however, the diversity of plant families and the distribution in remote areas represent a challenge for these protocols. Orchidaceae, one of the most species-rich plant families in the world, is a group with abundant polyphenols and polysaccharides in its tissues. In addition, sample collection in remote areas represents a challenge, consequently, conventional protocols can be inappropriate for obtaining DNA. In this way, CTAB-based gel preservation has emerged as an excellent alternative to easily collect, store and transport samples, moreover, alternatives such as sterile sand and DNA stabilization solutions during grinding allow a suitable DNA extraction. Here, we combined saturated NaCI-CTAB gels, sterile sand, sucrose-based DNA stabilization buffer, and conventional CTAB solution for obtaining DNA from fresh and stored samples for up to 32 days at room temperature, and described, from sample collection to spectrophotometer-obtained quantification, a non-organic method for obtaining DNA from orchids species for genomic applications. This protocol allows not only the extraction of suitable quantities of high molecular weight DNA of adequate purity and integrity from different orchid species without the use of expensive equipment and cumbersome reagents such as liquid nitrogen and toxic phenols, and/or time-consuming procedures, but also, the use of this DNA in downstream applications such as PCR-based genotyping, restriction enzyme analysis, and most genomic applications.

The widespread Coronavirus Disease 2019 (COVID-19) is caused by infection with the novel coronavirus SARS-CoV-2. Currently, we have a limited toolset available for visualizing SARS-CoV-2 in cells and tissues, particularly in tissues from patients who died from COVID-19. Generally, single-molecule RNA FISH techniques have shown mixed results in formalin fixed paraffin embedded tissues such as those preserved from human autopsies. Here, we present a platform for preparing autopsy tissue for visualizing SARS-CoV-2 RNA using RNA FISH with amplification by hybridization chain reaction (HCR). We developed probe sets that target different regions of SARS-CoV-2 (including ORF1a and N) as well as probe sets that specifically target SARS-CoV-2 subgenomic mRNAs. We validated these probe sets in cell culture and tissues (lung, lymph node, and placenta) from infected patients. Using this technology, we observe distinct subcellular localization patterns of the ORF1a and N regions, with the ORF1a concentrated around the nucleus and the N showing a diffuse distribution across the cytoplasm. In human lung tissue, we performed multiplexed RNA FISH HCR for SARS-CoV-2 and cell-type specific marker genes. We found viral RNA in cells containing the alveolar type 2 (AT2) cell marker gene (SFTPC) and the alveolar macrophage marker gene (MARCO), but did not identify viral RNA in cells containing the alveolar type 1 (AT1) cell marker gene (AGER). Moreover, we observed distinct subcellular localization patterns of viral RNA in AT2 cells and alveolar macrophages, consistent with phagocytosis of infected cells. In sum, we demonstrate the use of RNA FISH HCR for visualizing different RNA species from SARS-CoV-2 in cell lines and FFPE autopsy specimens. Furthermore, we multiplex this assay with probes for cellular genes to determine what cell-types are infected within the lung. We anticipate that this platform could be broadly useful for studying SARS-CoV-2 pathology in tissues as well as extended for other applications including investigating the viral life cycle, viral diagnostics, and drug screening.

In this study, serial dilutions of SARS-CoV 2 RNA extract were tested using RT-dPCR using three different primer-probe assays aiming SARS-CoV 2 nucleocapsid coding region. Narrower confidence intervals, indicating high quantification precision were obtained in 100 and 1000-fold serial dilution and RT-dPCR results were equivalent between different assays in the same dilution. High accuracy of this test allowed conclusions regarding the ability of this technique to evaluate precisely the amount of genomic copies present in a sample. We believe that this fast and safe method can assist other researchers in titration of SARS-CoV2 controls used in RT-qPCR without the need of virus isolation.

Nucleic acid purification is essential for molecular biology workflows, enabling successful downstream applications like cloning, sequencing, and PCR amplification. While commercial kits are widely used for DNA extraction from PCR products and agarose gels, their high costs can burden resource-limited laboratories. To provide a viable alternative, we developed an optimized, cost-effective in-house protocol for high-yield DNA purification. This study evaluates the performance of our protocol for plasmid DNA and PCR products, comparing it with commercial kits from Qiagen, Thermo Fisher, and WizBio in terms of cost, time, DNA concentration, and purity. Results from gel electrophoresis demonstrated that the in-house protocol significantly enhances PCR product clarity and reduces background smearing, yielding high-purity DNA compatible with sensitive applications. Restriction-digested plasmid samples showed successful ligation and transformation in E. coli (DH5), with Sanger sequencing chromatogram further confirming the sequence integrity of the purified DNA. Our findings highlight the in-house protocol as a cost-effective, efficient, and reliable alternative to commercial kits, delivering high-quality DNA suitable for various molecular applications. This method offers an accessible and practical solution for laboratories seeking to optimize DNA purification under budget constraints.

Quantifying changes in DNA and RNA levels is essential in numerous molecular biology protocols. Quantitative real time PCR (qPCR) techniques have evolved to become commonplace, however, data analysis includes many time-consuming and cumbersome steps, which can lead to mistakes and misinterpretation of data. To address these bottlenecks, we have developed an open-source Python software to automate processing of result spreadsheets from qPCR machines, employing calculations usually performed manually. Auto-qPCR is a tool that saves time when computing qPCR data, helping to ensure reproducibility of qPCR experiment analyses. Our web-based app (https://auto-q-pcr.com/) is easy to use and does not require programming knowledge or software installation. Using Auto-qPCR, we provide examples of data treatment, display and statistical analyses for four different data processing modes within one program: (1) DNA quantification to identify genomic deletion or duplication events; (2) assessment of gene expression levels using an absolute model, and relative quantification (3) with or (4) without a reference sample. Our open access Auto-qPCR software saves the time of manual data analysis and provides a more systematic workflow, minimizing the risk of errors. Our program constitutes a new tool that can be incorporated into bioinformatic and molecular biology pipelines in clinical and research labs.

Mitochondrial DNA copy number (mtDNA-CN) is a proxy for mitochondrial function and has been of increasing interest to the mitochondrial research community. There are a number of ways to measure mtDNA-CN, ranging from qPCR to whole genome sequencing [1]. A recent article in the Journal of Molecular Diagnostics [2] described a novel method for measuring mtDNA-CN that is both inexpensive and reproducible. After adapting the assay for use in our lab, we have found it to be reproducible and well-correlated with mtDNA-CN derived from whole genome sequencing. However, certain individuals show poor concordance between the two measures, particularly individuals with qPCR mtDNA-CN measurements >3 standard deviations below the sample mean, which corresponds to roughly 1% of assayed individuals (Figure 1). After examining whole genome sequencing data, this seems to be due to specific polymorphisms within the D-loop primer region, at positions MT 338, 340, 452, 457, 458, 460, 461, 466, and 467. All individuals with a variant in at least one of these positions have non-concordant mtDNA-CN measurements. Meanwhile, variants observed at other positions within the primer region do not appear to cause dropout. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/463983v1_fig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@134ca51org.highwire.dtl.DTLVardef@ce9196org.highwire.dtl.DTLVardef@1b82af6org.highwire.dtl.DTLVardef@c9701_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO Discrepancy between the monochrome multiplex qPCR mtDNA-CN and the whole genome sequencing mtDNA-CN for 1,732 distinct individuals. Data are centered at 0 and scaled so that the standard deviation = 1. The dotted red line represents 3 standard deviations beneath the sample mean. Individuals in the U, L1, L4, and T haplogroups have a disproportionately higher risk of discordant measures between the two assays. C_FIG

Biomedical research studies, specifically regarding human neurodegenerative diseases, are bound by ethical challenges, and have limited diagnostic and treatment options. Transgenic mouse models offer an incredible research advantage to conduct feasible and practical research with the ability to precisely define the progression of neurodegenerative disease over a wellcontrolled dosage and timeline. The use of transgenic mouse models has been extensive and is critical to advancing research in many ways, including understanding brain morphology and general tissue changes caused by neurological diseases. Often, these studies require specific brain regions or other neurological tissues which may be difficult to obtain. Unfortunately, specific extraction and dissection protocols are few and far between, leading to inconsistent results and a lack of reproducibility. A well-defined protocol, such as this, is instrumental in overcoming these obstacles and acquiring better experimental results. Five mouse-specific protocols are described: brain extraction, brain microdissection, spinal cord extrusion, cerebral spinal fluid (CSF) collection, and sciatic nerve dissection. Each protocol was completed under biosafety level 2 (BSL-2) guidelines, similar to the sterility precautions required in human surgery. Each protocol also includes a collective materials list that defines proper instruments and usage. The protocol was refined based on feedback from numerous research studies in transcriptomics and pharmaceutical development. These applications require minimizing tissue damage, dissection accuracy, and the ability to reproduce the results--skills that are also directly transferable to clinical settings. The proper implementation of these protocols will allow for more accurate and precise results with reduced variability. This study provides well-defined, succinct, accessible protocols that are more ethical and improve the overall quality of the conducted research. By addressing this need, it supports greater advancements in many cross disciplinary areas.

Herbaria harbor a tremendous amount of plant specimens that are rarely used for plant systematic studies. The main reason is the difficulty to extract a decent quantity of good quality DNA from the preserved plant material. While the extraction of ancient DNA in animals is well established, studies including old plant material are still underrepresented. In our study we compared the standard Qiagen DNeasy Plant Mini Kit and a specific PTB-DTT protocol on two different plant genera (Xanthium L. and Salix L.). The included herbarium material covered about two centuries of plant collections. A selected subset of samples was used for a standard library preparation as well as a target enrichment approach. The results revealed that PTB-PTT resulted in higher quantity and quality regarding DNA yield. For relatively recent herbarium specimens, and despite the lower overall yield of DNA, the Qiagen Kit resulted in better sequencing results regarding the number of filtered and mapped reads. We were able to successfully sequence a sample from 1820 and conclude that it is possible to include old herbarium specimens in NGS approaches. This opens a treasure box for phylogenomic research.

Salivary microRNAs (miRNAs) have been recently revealed as the next generation of non-invasive biomarkers for the diagnostics of diverse diseases. However, their short and highly homologous sequences make their quantification by RT-qPCR technique highly heterogeneous and study dependent, thus limiting their implementation for clinical applications. In this study, we evaluated the use of a commercial RT-qPCR kit for quantification of salivary miRNAs for clinical diagnostics. MethodsSaliva was sampled from ten healthy volunteers for a time course analysis. A panel of six miRNA targets (with different sequence homologies) were analysed by one of the most commonly used commercially available RT-qPCR kit. Sensitivity and specificity of the tested miRNA assays were corroborated using synthetic miRNAs. The reliability of all tested assays to differentiate miRNA expression profiles were analysed, to statistically discriminate background noise from intrinsic individual signals. ResultsSignificant variabilities in expression profiles of six miRNAs from ten healthy participants were revealed, yet the poor specificity of the assays offered insufficient performance to associate these differences to biological context. Indeed, as the limit of quantification (LOQ) concentrations are from 2-4 logs higher than that of the limit of detection (LOD), the majority of the analysis for salivary miRNAs felt outside the quantification region. Most importantly, a remarkable number of crosstalk reactions exhibiting considerable OFF target signal intensities was detected, indicating their poor specificity and limited reliability. However, the spike-in of synthetic miRNA increased the capacity to discriminate endogenous salivary miRNA at the LOQ concentrations from those that were significantly lower. ConclusionsOur results demonstrate that comparative analyses for salivary miRNA expression profiles by this commercial RT-qPCR kit are most likely associated to technical limitations rather than to biological differences. In particular, assessment of fundamental parameters including LOD, LOQ and crosstalk of each assay is strictly necessary to interpret observed variations. The standardization of rigorous sample handling and experimental design according to technical parameters of each assay plays a crucial role in reducing data inconsistencies across studies. However, further technological breakthroughs are still required to overcome discrepancies in order to accelerate the translation of salivary miRNAs for clinical applications.

Methods to visualize gene expression in the Drosophila central nervous system are important in fly neurogenetic studies. In this chapter, we describe a detailed protocol that sequentially combines in situ hybridization chain reaction (HCR) and immunostaining to detect mRNA and protein expression in whole-mount Drosophila larval and adult central nervous systems. We demonstrate the application of in situ HCR in comparisons of nervous system gene expression between Drosophila species, and in the validation of single-cell RNA-Seq results in the fly nervous system. Our protocol provides a simple, robust, multiplexable, and relatively affordable means to quantitatively visualize gene expression in the nervous system of flies, facilitating its general use in fly neurogenetic studies.

The commercialisation of miniprep kits supplanted the original alkaline lysis method for plasmid DNA preparation, and had remained relatively unchanged for almost two decades. The Miraprep substantially improved the yields of miniprep kits. However, the method still relies on commercial kits, which can be a burden financially to certain projects. Additionally, Pronobis et al. also identified loss of RNAse activities in miniprep kits over time. The present novel plasmid DNA isolation protocol addresses the two issues mentioned above utilising alkaline lysis and alkaline hydrolysis principles. With a largely identical workflow and operation time, the Macerprep will significantly reduce costs of establishing new laboratories as well as maintenance of running molecular biology laboratories.

In situ hybridization (ISH) of RNA is a key method to visualize gene expression patterns in complex biological samples. The technique is indispensable for biological research related to e.g. development, disease, gene function, and the validation of novel cell types identified by single-cell sequencing methods. Especially in non-mammalian models lacking accessibility to a broad spectrum of antibodies, ISH remains a major research tool. Diverse available ISH protocols require different custom hybridization probe types, design, and/or proprietary signal detection chemistry. This makes it hard to navigate for a beginner and increases the research costs when multiple methods need to be applied. Here, we describe OneSABER - a unified open platform connecting commonly used canonical and recently developed single- and multiplex, colorimetric, and fluorescent ISH approaches. This platform uses a single type of ISH DNA probes adapted from the signal amplification by exchange reaction (SABER) method. We demonstrate applications of the proposed ISH framework in whole-mount samples of the regenerative flatworm Macrostomum lignano, advancing this animal as a powerful model for stem cell and regeneration research.