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BioTechniques

Informa UK Limited

Preprints posted in the last 90 days, ranked by how well they match BioTechniques's content profile, based on 25 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

1
Recombinase polymerase amplification: characterization and mitigation of undescribed multimeric artefacts

De Keyzer, L.; Deserranno, K.; Skevin, S.; Van Hoofstat, D.; Deforce, D.; Van Nieuwerburgh, F.

2026-08-21 biochemistry 10.64898/2026.08.21.741777 medRxiv
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Recombinase polymerase amplification (RPA) enables rapid nucleic acid testing in low-resource environments, but poorly characterized byproducts can compromise assay specificity and cause false-positive results. Here, we amplified the thirteen original CODIS core loci and Amelogenin to characterize recurrent RPA artefacts and establish conditions that reduce their formation. First, RPA products were analyzed for two reference samples by Oxford Nanopore Technologies sequencing. This revealed two distinct classes of multimeric products: primer multimers and amplicon multimers, consisting of repeated primer or amplicon sequences, respectively. Individual artefacts contained up to 281 primer copies or 22 amplicon copies, demonstrating the extensive range of these products. Next, we performed an optimization study to evaluate the effects of reaction temperature and reagent concentrations at two representative loci, D3S1358 and D5S818. Among the conditions tested, temperature had the most pronounced effect. Reducing the temperature from 42{degrees}C to 34{degrees}C increased the relative target amplicon fraction from 15% to 83% for D3S1358 and from 84% to 98% for D5S818, while maintaining or increasing absolute target concentration. Lower primer concentrations and higher T4 UvsX concentrations also reduced multimer formation, although lower primer concentrations reduced target yield and caused allelic dropout. Finally, amplification at 34{degrees}C was evaluated across all fourteen loci by sequencing. Relative to 42{degrees}C, the target read fraction increased by more than 5 percentage points for 7/14 loci in one reference sample and 9/14 loci in the other, with the largest improvements at multimer-prone loci. These findings identify multimers as an important class of RPA artefacts and establish reaction temperature and T4 UvsX concentration as promising conditions to improve RPA specificity.

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qPCR Guru, a free browser-based platform, strengthens microRNA analyses using full-curve Cq estimation

Singh, A.;Singh, O.;Sarkar, M.;Coultous, R.;Stice, S.

2026-06-23 Molecular Biology 10.64898/2026.06.21.733609 medRxiv
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Quantitative PCR (qPCR) depends on reliable quantification cycle (Cq) estimation from amplification curves, which are not always well-behaved. We developed qPCR Guru to provide a complete analysis pipeline including data quality assessment, relative quantification, standard-curve diagnostics, and dual-method Cq evaluation. The latter compares the conventional instrument-derived threshold ("Reported") Cq versus the full-curve five-parameter logistic (5PL) second-derivative-maximum ("Fit") Cq and automatically flags curve-shape abnormalities and disagreement between the two estimates. On high-expressing targets (mRNA and microRNA), the two methods showed strong convergence, confirming general-purpose performance. On low-expressing targets, such as serum microRNA, baseline artifacts and biphasic amplification result in threshold miscalls that standard instrument analysis does not flag. Fit Cq restored replicate-concordant values where Reported Cq split the technical replicates by 17-20 cycles, recovered MIQE-compliant amplification efficiencies lost to biphasic miscalls (from 74% to 102% and 387% to 98%), and lowered within-group variability by 48% and 68% in feline and bovine samples, respectively. Together, these results demonstrate that full-curve estimation, with integrated curve-level diagnostics, strengthens qPCR analyses against threshold miscalls. ARTICLE HIGHLIGHTSO_LIqPCR Guru is a free, browser-based platform that provides a complete analysis pipeline and facilitates side-by-side comparisons of an instruments threshold (Reported) Cq and a full-curve (Fit) Cq, from the five-parameter logistic fitting with second-derivative-maximum (SDM/cpD2). C_LIO_LIFor every well the application automatically flags curve-shape abnormalities and disagreement between the two Cq estimates. C_LIO_LIOn clean, high-expressing mRNA and microRNA targets, the two estimators (Reported Cq and Fit Cq) were strongly concordant and produced equivalent relative quantification with comparable precision. C_LIO_LIIn low-expressing serum microRNA, baseline artifacts and biphasic amplification produced threshold Cq miscalls of up to [~]20 cycles and were detected by curve-shape flags and/or method disagreement. C_LIO_LIThe full-curve Cq estimate recovered replicate-concordant values, restored MIQE-compliant amplification efficiencies, and reduced within-group variability in serum microRNA. C_LI

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OddCAPS: a simple, low-cost, universal technique for detecting single nucleotide variants

Kawaguchi, K.; Komachiya, Y.; Muto, M.; Teshima, R.; Sakai, N.; Ohno, H.

2026-07-16 molecular biology 10.64898/2026.07.16.738826 medRxiv
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Derived Cleaved Amplified Polymorphic Sequences (dCAPS) assays have been widely performed historically to detect known base substitutions in many model organisms--notably Caenorhabditis elegans, Arabidopsis thaliana, Saccharomyces cerevisiae, and Schizosaccharomyces pombe-- where chemical mutagens that induce point mutations are frequently used. With the rise of whole-genome sequencing and genome editing technologies, dCAPS is increasingly applied to detect diverse nucleotide changes in additional organisms, including Drosophila, zebrafish, mammals, and agricultural crops (e.g., Oryza sativa and Hordeum vulgare). However, a key limitation of dCAPS is that genomic target sites amenable to primer designs that both preserve PCR amplification and create recognition sites for inexpensive, high-performance restriction enzymes are scarce. Here we report One-step dual-primer dCAPS (OddCAPS), a modification that uses three primers in one reaction to overcome this constraint. Two of these primers, an intermediate primer and a dCAPS primer, sequentially introduce 1-2 base substitutions each into the amplicon, enabling up to four engineered base changes near the nucleotide of interest. By using the intermediate primer at 1/10-1/100 the concentration of the other primers, the desired product is generated directly in a single-tube, one-step PCR. Increasing the number of engineered substitutions improves the chance of using a researchers preferred restriction enzyme. In principle, having eight common restriction enzymes (BamHI, EcoRI, NheI, SalI, BglII, ClaI, HindIII, and MluI) suffices to detect any single-nucleotide variant in any biological or synthetic DNA sequence with this approach.

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Development of Shelf-Stable Reagents and Assay Kits for Bioluminescence Applications using the Capillary-Assisted Vitrification Platform Stabilization Technology

Shank-Retzlaff, M.; Radford, S.; Peris-Taverner, Y.; Dibble, M.; Corn, K.; Zhu, T.; Martello, S.; Mayeau, M.; Ladd, A.; Renu, S.; Chunduri, T.; Jadhav, A.; Dart, M.; Rafat, M.; Bronsart, L.

2026-07-13 biochemistry 10.64898/2026.07.11.737891 medRxiv
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Luminescence is a powerful method for detecting trace analytes and monitoring biological processes. However, most bioluminescence reagents, including luciferase and its substrates, are sensitive to temperature, limiting their useable shelf lives, and resulting in inconsistent performance. Enhancing the stability of these reagents could improve data quality, simplify workflows, and address cold chain storage issues. In this study, we demonstrate the application of the platform stabilization technology, capillary-assisted vitrification (CAV), as a tool to stabilize different luciferases and their substrates, and the application of the stabilized reagents in both in vitro and in vivo bioluminescent assays. We demonstrate that CAV-stabilized reagents can be stored and shipped ambiently, maintain consistent performance over time, and are suitable for use in cell viability quantification, tumor monitoring, in vivo imaging, microbial detection, and immunoassays. Additionally, different reagents can be co-formulated to make ready-to-use assay kits that can also be shipped and stored ambiently. Our results demonstrate that CAV stabilization is a viable alternative to traditional storage methods, with broad potential to improve bioluminescence workflows.

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A Portable Fluorescence Platform for Decentralized One-Health mcr-1 Monitoring

Vargas-Reyes, M.; Alcantara, R.; Herrera, C.; Townsend, M.; Flores-Jimenes, K.; Raymundo, C.; Milon, P.

2026-07-27 molecular biology 10.64898/2026.07.24.740582 medRxiv
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Antimicrobial resistance (AMR) represents a major global health threat, with plasmid-borne mcr genes driving colistin resistance and exposing critical gaps in One-Health surveillance across human, animal, and environmental reservoirs. The most prevalent variant, mcr-1, remains difficult to monitor in resource-limited settings due to the lack of rapid, affordable, and field-deployable molecular tools. Here, we developed C12amcr, an integrated molecular toolbox that combines pre-amplification PCR with a fluorescent CRISPR-Cas12a assay targeting a conserved region of mcr-1 and a custom low-cost, hand-held 3D-printed portable fluorometer. Under optimized conditions, the assay achieved a limit of detection of 630 cells/mL. In poultry feces spiked with mcr-1-positive E. coli, C12amcr detected as few as 1,800 cells/mL. When tested on 22 community-derived E. coli isolates, the assay showed 100% concordance with both next-generation sequencing for mcr-1 detection and phenotypic colistin susceptibility testing by broth microdilution. The accompanying portable fluorometer performed equivalently to a laboratory microplate reader while enabling fully decentralized workflows compatible with portable PCR platforms. By integrating locally produced molecular reagents, straightforward protocols, and an accessible field-ready fluorescence reader, C12amcr overcomes key barriers to decentralized AMR surveillance and provides a practical, scalable solution for One-Health monitoring in resource-limited settings.

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A data-driven consensus framework for Ct interpretation in real-world multi-assay qPCR diagnostics

Wang, J.; Chen, J.; Zhao, B.; Zhang, G.; Jian, S.; Deng, T.; Liang, D.

2026-06-15 pathology 10.64898/2026.06.11.26355491 medRxiv
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While cycle threshold (Ct) values from quantitative PCR (qPCR) serve as the gold-standard indicators of target abundance, their clinical interpretation is frequently confounded by inherent variability across diverse assay designs, reagents, and instrumentation. In this study, we present a data-driven consensus framework for Ct evaluation that uses large-scale, multi-assay amplification data to establish reference patterns of normal Ct behavior. Based on a total of 41,770 amplification curves collected from four routine diagnostic assays across two PCR platforms, we evaluated machine learning models across three experimental scenarios: within-platform validation, cross-assay generalization, and cross-platform transfer. Extreme gradient boosting (XGBoost) achieved the most accurate and stable predictions under data-sufficient, within-platform conditions with a mean absolute error (MAE) of 0.0419, while pooled multi-assay training improved cross-assay robustness compared with single-assay models. Model performance was further assessed using a deviation-based metric to quantify differences between predicted and instrument-reported Ct values, allowing efficient identification of anomalous amplification curves in large datasets. Notably, direct application across platforms without recalibration led to a substantial decline in performance, with a MAE of 2.62, showing platform-dependent variability. These findings indicate strong stability under within-platform and cross-assay conditions, with scalability contingent upon appropriate cross-platform calibration.

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Strand Displacement Activity of Mimiviral Polymerase X Enables Rapid Detection of Sequence-Specific DNA Targets

S Raman, A.; Lad, S. B.; Mandal, S.; Paul, D.; Kondabagil, K.

2026-06-10 molecular biology 10.64898/2026.06.10.731134 medRxiv
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Mimiviral polymerase X, mvPolX, is a repair polymerase that is involved in base excision repair (BER) and carries out the gap-filling function in double-stranded DNA (dsDNA). We demonstrate a sensitive and sequence-specific DNA detection method using this polymerase. mvPolX begins polymerizing DNA from the 3 end of a gap, displacing the downstream nucleotides without exonuclease activity. Our detection method is built on this activity of mvPolX. We designed a probe molecule consisting of a partial dsDNA with a 3 over-hang region complementary to the target DNA to be detected. The probe has a fluorophore-quencher (FAM-BHQ1) tag to facilitate detection upon strand removal. Binding of the probe to the complementary target forms a dsDNA with a single nucleotide gap in one strand. mvPolX binds this gap region and begins polymerisation eventually displacing the quencher strand leading to an increase in fluorescence. Proof-of-concept has been established using a synthetic 19 bp target DNA sequence. The method is specific and did not show any strand displacement when a single or double mismatched nucleotide at the 3 end of the target DNA was used. To demonstrate this molecular assay, we used M13 phage as our target. Asymmetric PCR (aPCR) was used to obtain single-stranded target DNA (158 bases) from M13 genomic DNA, which was directly used in the assay as target. The combination of aPCR and mvPolX assay can detect as low as 10 copies of genomic DNA. The enzymatic reaction is fast, requiring only 15 min of incubation with mvPolX at 30 {degrees}C. We have further demonstrated the efficiency of the assay in presence of multiple non-target DNA by detecting the target DNA from M13 phage spiked lakewater samples.

8
Analytical Validation of Automated DNA Isolation from Meat Matrices for High-Quality PCR-Based Food Authentication

Dewi, Y. K.; Chudori, Y. N.

2026-07-20 molecular biology 10.64898/2026.07.17.739293 medRxiv
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Reliable DNA isolation is a critical prerequisite for PCR-based food authentication, particularly for meat products where complex matrices may compromise DNA quality and amplification efficiency. This study aimed to analytically validate an automated DNA extraction method from meat matrices using Qiagen QIAcube Connect in combination with the DNeasy(R) Mericon Food Kit. Validation parameters included DNA concentration, total yield, purity, integrity, and assessment of PCR inhibitors using real-time PCR targeting the porcine cytochrome b gene. The method produced a mean DNA concentration of 219.5 ng/{micro}L with an average yield of 21,519.7 ng, exceeding predefined acceptance criteria. Agarose gel electrophoresis confirmed DNA fragment sizes larger than the target amplicon, indicating suitability for PCR analysis. Real-time PCR evaluation demonstrated excellent linearity (R2 = 0.99-1.00), amplification efficiencies between 90.34% and 99.84%, and mean {Delta}Ct values of 0.10, confirming the absence of PCR inhibition. These results indicate that the validated automated method is robust, reproducible, and suitable for routine PCR-based meat species authentication in food control laboratories.

9
Hot Pursuit: Bioinformatic and Biochemical Characterization of a Hyperthermophilic Family B DNA Polymerase from Pyrolobus fumarii A1

Rusinek, W.; Dorawa, S.; Kaczorowski, T.

2026-06-26 biochemistry 10.64898/2026.06.25.734501 medRxiv
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Thermostable DNA polymerases are indispensable tools in molecular biology, yet enzymes from the most extreme hyperthermophiles remain largely uncharacterized. Here, we report the biochemical and structural characterization of a family B DNA polymerase from Pyrolobus fumarii A1 (Pyrfu pol), one of the most thermoresistant archaea described to date. The enzyme was efficiently overproduced in E. coli Rosetta 2(DE3)[pLysS] and purified to homogeneity using a two-step protocol that combined heat treatment with immobilized metal affinity chromatography (IMAC). Bioinformatic analysis confirmed the canonical family B architecture, while AlphaFold-based structural modeling and comparative analysis with mesophilic RB69 DNA polymerase revealed a well-conserved structural core alongside thermoadaptive features. Radiolabel incorporation assays demonstrated enzymatic activity over a broad ionic strength range and an absolute requirement for Mg ions. PCR-based optimization confirmed these findings and revealed broad pH tolerance (6.5-11.0). Notably, Tris inhibited radiolabel-based assays (pH 7.0) yet proved essential for efficient PCR amplification (pH 8.5), suggesting a context-dependent role of buffer composition in polymerase activity. Processivity assays confirmed amplification of DNA fragments up to approximately 8,000 bp. Replication fidelity, assessed by the lacZ-based assay, showed a 2.9-fold improvement over Taq polymerase. Urea-nanoDSF yielded an exceptional melting temperature of 105.9 {+/-} 0.08 {degrees}C. Pyrfu pol also demonstrated tolerance to common PCR inhibitors, highlighting its potential utility in molecular biology applications.

10
Development of a multiplex immunofluorescence panel to study heterogenous cancer-associated fibroblast subtypes with spatial resolution

Burley, A.; Silveira, T.; James, N.; Salto-Tellez, M.; Wilkins, A. C.

2026-07-01 pathology 10.64898/2026.06.26.734718 medRxiv
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Background: Single cell RNA sequencing provides a wealth of information to explore the complexities of the tumour microenvironment, but crucially the spatial topology of the tumour is lost and studying cellular interactions is limited. Spatial transcriptomics aims to address this however the technique remains cost prohibitive for the generation of data from meaningfully-sized clinical cohorts. In contrast, spatial proteomic profiling with multiplex immunofluorescence, preserves spatial interactions, is relatively cost accessible, and is scalable for large clinical cohorts to address powerful translational questions. Whilst multiplex approaches have advanced in recent years, we note that cancer-associated fibroblasts (CAFs) have been explored in less detail, potentially due to difficulties associated with CAF heterogeneity and the diversity of markers used to define them. Methods: We designed, optimised, and validated a multiplex immunofluorescence panel that combines four frequently used CAF markers; alpha smooth muscle actin (aSMA), fibroblast activation protein (FAP), podoplanin (PDPN) and platelet-derived growth factor receptor alpha (PDGFRa) with CD8 and pan-cytokeratin. Here we share our methodology and the practical considerations taken to inform the final panel design. We also highlight the benefits of robust optimisation experiments.

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Enhancing Recombinant Vector Assembly Efficiency: A Novel Methodological Approach

YUAN, S.; Jiang, H.; Wang, H.; Fu, M.; Wang, J.; Liu, Z.; Li, Y.

2026-08-01 biochemistry 10.64898/2026.07.30.741931 medRxiv
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With the rapid development of modern biotechnology, DNA vectors have become fundamental tools for inserting, transferring, and expressing specific gene sequences in various fields such as gene cloning, gene expression, gene editing, and gene therapy. However, when dealing with complex structured DNA sequences, traditional vector construction methods face challenges with low connection efficiency. This study proposes a new method for constructing recombinant vectors by employing a strategy of high-temperature treatment followed immediately by placement on ice, effectively reducing the complexity of DNA structures and enhancing the efficiency of PCR product-vector connection, thereby improving the construction efficiency of recombinant vectors. This paper describes the technical details of the method, experimental validation, and applications in gene cloning, gene recombination editing, and the preparation of gene therapy drugs, providing a new efficient tool for molecular biology experiments.

12
High thoughput fluorometric nucleic acid quantification using qPCR instruments

Meerson, A.

2026-08-06 molecular biology 10.64898/2026.08.01.742208 medRxiv
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To explore adapting qPCR systems for end-point nucleic acid quantification using dyes such as SYTO-9, we quantified serial dilutions of DNA and RNA standards in the range of 0.75 - 200 ng/{micro}l on 384-well qPCR devices. SYTO-9 fluorescence was successfully measured using standard SYBR Green settings. Blank-subtracted relative SYTO-9 signal showed a logarithmic dependence on DNA/RNA concentration (R2 > 0.95). Measurements were highly stable with different incubation times, temperatures of up to 95{degrees}C, and photobleaching. The described approach is a valuable QC option for high-throughput DNA/RNA isolations and could be adapted to additional fluorometric assays beyond nucleic acids.

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A rapid HPLC-based method to determine NAD(P)(H) and NMN redox cofactor concentrations and ratios in microbes

van Wijk, N. E.; van der Heijden, E. C. M.; Hernandez-Sancho, J. M.; Volke, D. C.; Nikel, P. I.; van Heerden, J. H.; Bruggeman, F. J.; Claassens, N. J.; Weusthuis, R. A.; Bisschops, M. M. M.

2026-07-24 biochemistry 10.64898/2026.07.24.740514 medRxiv
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Redox cofactors are a key part of cellular physiology as they are involved in most metabolic pathways, and their ratios are linked to cellular robustness. However, measuring their levels in cells remains a challenge. Here, we describe a novel method to rapidly measure NAD(H), NADP(H) and nicotinamide mononucleotide (NMN) levels and their oxidized/reduced ratios using an HPLC connected to a fluorescence detector. By extensively characterizing this method and benchmarking it against the classical iodonitrotetrazolium (INT) assay, we show that this method results in accurate and reproducible measurements of NAD+, NADP+ and NMN levels in bacteria. We further demonstrate that this method can be used to determine intracellular NADH and NADPH concentrations and ratios of nicotinamide nucleotide cofactors in engineered Escherichia coli strains, as well as other bacterial species such as Pseudomonas putida.

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Enriching the Human Stool Microeukaryotes for Shotgun Sequencing

Ozkurt, E.; Schneider, D.; James, S. A.; Hautefort, I.; Ahn-Jarvis, J.; Heavens, D.; Banzhaf, M.; Hayhoe, A.; Hildebrand, F.

2026-06-24 microbiology 10.64898/2026.06.24.734237 medRxiv
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The human gut microbiome harbours a diverse community of microeukaryotes, predominantly fungi, which may potentially play important roles in gut ecology and homeostasis. Despite their potential, the study of gut microeukaryotes has been hampered by the limited sensitivity of standard sequencing approaches, which struggle to capture DNA from low-abundance microorganisms against the overwhelming background of bacterial biomass. To address this, we developed a method to selectively enrich for microeukaryotic cells in human faecal samples by depleting bacterial cells prior to metagenomic sequencing. Through systematic comparison and optimisation at each processing step, we established a robust standard operating procedure (SOP) for microeukaryotic cell enrichment. By benchmarking this SOP across eight human faecal samples with three technical replicates each, we showed that it consistently increased microeukaryote representation in metagenomic libraries, greater microeukaryotic taxonomic diversity, and a reduced proportion of unclassified taxa. Together, these improvements enabled substantially deeper characterisation of the microeukaryotic fraction of the human gut microbiome.

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Alternative management strategy reshapes litter microbiome dynamics in a commercial broiler rearing system

Hale, B. M.; Priddle, C.; Gajurel, G.; Tamrakar, K.; Coles, M.; Mendonca Dias, L.; Rubinelli, P. M.; Olson, E. G.; Arnold, C.; Graham, D.; Shields, R. C.; Ricke, S. C.

2026-07-03 microbiology 10.64898/2026.07.01.735883 medRxiv
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Pre-harvest litter management is a key determinant of broiler production conditions, influencing NH3; generation, pathogen exposure, nutrient retention, and microbial reservoirs that accumulate across production cycles. Conventional chemical and physical management strategies can support flock health, but their effects on pathogen-associated bacterial populations are often transient and may not account for the microbial interactions that govern persistence, exclusion, and community succession. Here, we evaluated an alternative litter management strategy combining IndigoLT pre-/postbiotic with reduced-rate NaHSO4; across two broiler growouts, with litter sampled at the end of each flock to determine impact on prokaryotic microbiome structure, physicochemistry, and Enterococcus abundance. Alternative management influenced observed richness, phylogenetic diversity, community composition, and co-occurrence network structure while reducing the relative abundance of Enterococcus, including E. cecorum and E. hirae. Digital PCR corroborated sequencing-based Enterococcus abundance patterns, although 16S-based treatment effects were not always reflected as lower absolute copy number at terminal sampling, consistent with reduced proportional dominance rather than sustained absolute suppression. Complementary biofilm- and growth-inhibition assays performed with IndigoLT demonstrated context-dependent antibiofilm and bacteriostatic activity against reference and poultry-derived Enterococcus isolates, with stronger responses for E. cecorum than E. hirae and bactericidal-level reductions in viable recovery at higher exposure levels. These findings demonstrate that biologic-based litter management can alter microbiome structure and pathogen-associated taxa under commercial production conditions, providing a basis for microbiome-informed amendment strategies aimed at reducing pathogen load and supporting broiler health.

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A Scalable Framework for Species-Resolved Human Gut Microbiome Profiling Using Full-Length 16S rRNA Sequencing

Sarin, P.; Sehgal, P.; Paveri, V.; Rai, S.; Chettri, A.; Bhoyar, R. C.; Karkaryate, R.; Mirza, S.; Gupta, S. S.; Sivasubbu, S.; Parsannanavar, D. J.

2026-06-23 genomics 10.64898/2026.06.21.732309 medRxiv
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The gut microbiota plays a fundamental role in human health, nutrition, immune development, and disease, driving widespread adoption of 16S rRNA gene sequencing for microbial community characterization. Short-read V3-V4 sequencing remains the dominant approach for large-scale microbiome studies; however, interrogation of only a small fraction of the 16S gene limits phylogenetic resolution and frequently restricts biological interpretation at the species level. Although full-length (V1-V9) 16S sequencing has emerged as a promising alternative, comprehensive evaluation of highly multiplexed full-length workflows in complex human gut microbiomes remains limited. Here, we establish and evaluate a full-length 16S framework for species-resolved human gut microbiome profiling. The workflow was assessed using defined microbial communities, technical replicates, and healthy human fecal microbiomes. Full-length sequencing generated highly concordant taxonomic profiles across independent technical workflows and enabled reproducible recovery of complex microbial communities at both genus and species levels. Application to human fecal microbiomes revealed substantial inter-individual heterogeneity together with extensive ASV-level microdiversity, highlighting the ability of full-length sequencing to resolve fine-scale phylogenetic variation within dominant gut-associated taxa. To quantify the analytical gain afforded by full-length sequencing, V3-V4 datasets were computationally reconstructed directly from identical full-length reads, eliminating methodological and biological confounders. While alpha diversity metrics and overall community structure remained highly concordant between approaches, full-length sequencing markedly improved taxonomic resolution, increasing species-level assignment from approximately 20% to 98% and resolving substantial intra-genus diversity within clinically and ecologically relevant genera including Bifidobacterium, Prevotella, Blautia, Enterococcus, and Klebsiella. Collectively, these findings position full-length 16S sequencing as an enabling technology for the next generation of microbiome studies, where species-level resolution can be integrated with large-scale cohort, longitudinal, and population-health investigations.

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First detection of peroxynitrite in live coral cells during thermal stress

Fuller, I. D.; Fetkenhour, K. P.; Kumar, G. D.; Domaille, D. W.; Roger, L. M.

2026-07-15 biochemistry 10.64898/2026.07.14.738561 medRxiv
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Reactive nitrogen species (RNS), particularly peroxynitrite generated from the reaction of superoxide and nitric oxide, are implicated in thermally-induced oxidative stress but remain difficult to resolve in live coral cells. We optimized fluorescent dye strategies to directly quantify superoxide, nitric oxide, and peroxynitrite production in thermally stressed Pocillopora acuta cell suspensions. Thermal stress was associated with an increase in intracellular peroxynitrite concentration, but not in its precursors, nitric oxide and superoxide, highlighting challenges with the application of fluorescent probes and their controls to live coral cells. Compounds developed for mammalian systems often translate poorly to non-model systems such as corals: strong endogenous fluorescence and multiple membrane barriers within the coral symbiocyte, for instance, limited the function of the nitric oxide probe, DAF-2DA. Despite these limitations, the detection of peroxynitrite in live, thermally stressed P. acuta cells represents a step forward in understanding the mechanism of coral bleaching. We also outline strategies for improving the performance of commercial dyes in non-model systems, including media optimization with EDTA treatment to preserve both cell viability and probe performance.

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Coated Bacterial Enzymes: A one-step approach for enzymatic purification and immobilization

Ramirez Gutierrez, A. C.; Harguindeguy, I.; Homse, M. S.; Sabetta, A. E.; Cavalitto, S. F.; Ortiz, G. E.

2026-07-09 biochemistry 10.64898/2026.07.08.735634 medRxiv
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The purification of industrial enzymes typically relies on costly, multi-step chromatographic protocols. To address this, we developed a novel platform termed Coated Bacterial Enzymes (CBEs), which enables one-step purification and immobilization of recombinant proteins fused to the SlpA cell wall binding domain. As a proof of concept, we used a {beta}-galactosidase from Bifidobacterium bifidum of dairy relevance. The chimeric enzyme BbgII-SlpA was expressed in Escherichia coli and captured from crude lysate onto glutaraldehyde-inactivated Bacillus subtilis cells via SlpA domain. Binding was characterized by a dissociation constant (Kd) of 16.2 {micro}M and maximum binding capacity (Bmax) of 144 {micro}mol/g. The resulting CBE biocatalyst exhibited optimal activity at pH 6.0 for ONPG and lactose, with a broader pH profile than the free enzyme. Optimal temperatures were 60 {degrees}C for ONPG and 50 {degrees}C for lactose, and CBE retained >80% activity after 390 min at 45 {degrees}C, compared to 20% for the free enzyme. Catalytic efficiencies (kcat/Km) were 2.62 x106 M-1{middle dot}s-1 for ONPG and 4.40 x102 M-1{middle dot}s-1 for lactose. Moreover, CBE showed improved tolerance to cations such as Ca2+ and Fe2+. These results suggest that the CBE platform offers a cost-effective alternative for producing high-purity, immobilized enzymes for diverse industrial bioprocesses.

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A Sample to Results Workflow for Compositional Analysis of Multiplexed Amplicon Sequencing Experiments

Bennett, A.; Moore, R. M.; Herbold, C. W.; Hanson, T. E.

2026-07-28 microbiology 10.64898/2026.07.28.741237 medRxiv
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Microbial communities play key roles in the transformation and cycling of elements ranging from required macronutrients to toxic metalloids. Next-generation sequencing has been applied across multiple ecosystems to probe the interplay of microbial community structure and functional potential with respect to elemental cycling. Shotgun metagenomics collects marker gene sequences without amplification and is costly for large numbers of samples and deep coverage. Conversely, amplicon sequencing of taxonomic marker genes, e.g. 16S and 18S rRNA, is cost-effective for large numbers of samples, but provides limited functional insight. A middle ground between the two approaches is needed to analyze community structure and functional potential within a sample while remaining cost-effective with high throughput. To address this need, we developed a standardized workflow for multiplexed amplicon sequencing from sample collection through data analysis for diverse sample types, including freshwater, sediments, and soils, that produces data and publication-ready figures for multiple taxonomic and functional genes for carbon, nitrogen, phosphorus, sulfur, and arsenic cycling for each sample analyzed. The workflows utility was shown by analyzing 11 taxonomic and functional gene amplicons sequenced from 25 samples with high technical replicate similarity. The workflow is named CAMASE for Compositional Analysis of Multiplex Amplicon Sequencing Experiments. This proof-of-concept shows that CAMASE economically produces standard amplicon sequencing outputs (ASV/OTU counts and taxonomy, PCA, and relative abundance plots) for hundreds of amplicon by sample combinations and provides specific recommendations for implementation. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/741237v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@14c746corg.highwire.dtl.DTLVardef@6f9890org.highwire.dtl.DTLVardef@894038org.highwire.dtl.DTLVardef@d72b2a_HPS_FORMAT_FIGEXP M_FIG C_FIG Samples are collected in a preservative and material collected on filters prior to DNA extraction. Target gene amplicons are produced in parallel with internal barcodes enabling sequencing in a single run followed by compositional data analysis. All wet lab protocols, code markdowns, and templates for required metadata files are available at https://hansonlabgit.dbi.udel.edu/aprange/CAMASE. Created in BioRender. Bennett, A. (2026) https://BioRender.com/ymnojt0

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Validation of a high throughput fluorescent Capillary Electrophoresis Sodium Dodecyl Sulfate method for monoclonal antibody size heterogeneity assessment

Luttgeharm, K. D.; Grover, M.; Huang, S.-Y.; Pike, W. A.

2026-07-16 biochemistry 10.64898/2026.07.15.738750 medRxiv
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Fluorescent capillary gel electrophoresis (CGE) with sodium dodecyl sulfate (CE-SDS) provides a powerful, high-sensitivity alternative to ultraviolet (UV)-based detection for characterizing therapeutic monoclonal antibodies (mAb). Regulatory and standards organizations, such as the United States Pharmacopeia (USP), include only UV based CE-SDS methods, hindering adoption, of alternative detection methods. There is growing opportunity to expand beyond exclusively UV-based CE-SDS methods. In this study, we present a full analytical validation of a light-emitting diode (LED) fluorescence-based parallel CE-SDS method for both non-reduced and reduced analysis of therapeutic antibodies. Using the NISTmAb reference material as a model system, size heterogeneity critical quality attributes (CQAs) including monomeric purity, percent glycosylation, and percent thioether were assessed. The fluorescence method demonstrated high specificity and precision with relative standard deviation (RSD) values <1% for monomeric purity and glycosylation, and <3% for thioether), as well as robust performance across variations in injection voltage, electrophoresis voltage, labeling temperature, and Labeling Buffer concentration. Ruggedness testing across users and reagent lots confirmed reproducibility, and accuracy assessments showed strong agreement with reported values from the National Institute of Standards (NIST) and traditional UV detection measurements. Linearity studies yielded coefficient of determination (R2) values >0.995 for both non-reduced and reduced analyses. These results highlight the high sensitivity, stable baseline performance, and suitability of LED fluorescence-based parallel CE-SDS as a validated, higher-throughput alternative to traditional UV-based methods for mAb quality control (QC).