Biology subjects

Munds, R. A.

Publications and source records attributed to Munds, R. A..

3 recordsLinked to original sources

bioRxiv2026

A solid-state heater-imager for quantitative evaluation of colorimetric isothermal nucleic acid amplification on paper

Maintaining precise isothermal conditions in portable nucleic acid amplification tests (NAATs) is critical for reproducible results but remains challenging with conventional single-sided thin-film heaters, which exhibit temperature gradients and strong dependence on ambient conditions. To close this gap, we engineered ThermiQuant VitroMini, a dual-sided heater design that achieves volumetric-level temperature uniformity using thin-film heaters while preserving optical transparency for real-time colorimetric loop-mediated isothermal amplification (LAMP) analysis on microfluidic paper-based analytical devices ({micro}PADs). The device integrates two independently regulated indium tin oxide (ITO) heaters (8 {Omega} each) controlled by independent proportional-integral-derivative (PID) algorithms. Heaters were evaluated under controlled ambient environments of 4 {degrees}C (refrigerated), 23 {degrees}C (room temperature), and 50 {degrees}C (oven). Analytical tests were performed using a colorimetric LAMP assay targeting the SARS-CoV-2 orf7ab gene on {micro}PADs preloaded with dried LAMP reagents, with time-lapse images (30 seconds interval) analyzed via Amplimetrics software. VitroMini maintained 65 {+/-} 0.5 {degrees}C across 4 to 50 {degrees}C ambient conditions and achieved a limit of detection of 34 copies/reaction (4.5 copies/{micro}L) and limit of quantification of 1000 copies/reaction (133 copies/{micro}L), with quantification time (Tq) linearly correlated with log10 DNA concentration. Dual-sided heating eliminated temperature bias, condensation artifacts, and ambient-dependent variability while preserving optical transparency for real-time quantitative LAMP reaction. ThermiQuant VitroMini bridges the gap between benchtop volumetric heaters and portable diagnostic devices, offering a compact, low-power platform for quantitative colorimetric molecular analysis on paper with potential for decentralized and field-deployable applications.

bioengineering↗

bioRxiv2024

Climate drives geographic variation in individual Peromyscus leucopus immunity against zoonotic disease.

Geographic variation in host immunity could have major influences on disease dynamics, including zoonotic forms that affect humans. Such variation in immunity could be driven by variation in climate, either directly or, more likely, indirectly via resource availability. We compared the immune gene expression of wild Peromyscus leucopus mice, the primary reservoir for the bacterium that causes Lyme disease, Borrelia burgdorferi, among eight sites spanning 1,400 km of the northeastern United States. We discovered that climate conditions at sites strongly predicted immunity to the most common zoonotic pathogen in the U.S.: mice from warmer, wetter sites were more prepared to resist B. burgdorferi infections. Our results reveal a novel pathway by which climate change could affect pathogen spillover or zoonotic epidemics generally.

immunology↗

bioRxiv2023

Bacterial sepsis triggers stronger transcriptomic responses in larger primates

Empirical data relating body mass to immune defense against infections remain limited. Although the Metabolic Theory of Ecology predicts that larger organisms would have weaker immune responses, recent studies have suggested that the opposite may be true. These discoveries have led to the Safety Factor hypothesis, which proposes that larger organisms have evolved stronger immune defenses because they carry greater risks of exposure to pathogens and parasites. In this study, we simulated sepsis by exposing blood from nine primate species to a bacterial lipopolysaccharide (LPS), measured the relative expression of immune and other genes using RNAseq, and fit phylogenetic models to determine how gene expression was related to body mass. In contrast to non-immune-annotated genes, we discovered hypermetric scaling in the LPS-induced expression of innate immune genes, such that large primates had a disproportionately greater increase in gene expression of immune genes compared to small primates. Hypermetric immune gene expression appears to support the Safety Factor hypothesis, though this pattern may represent a balanced evolutionary mechanism to compensate for lower per-transcript immunological effectiveness. This study contributes to the growing body of immune allometry research, highlighting its importance in understanding the complex interplay between body size and immunity over evolutionary timescales. Author SummaryUnderstanding the relationship between an animals size and its ability to defend against disease can inform predictions about evolutionary tradeoffs and susceptibility to infection. Two major theories - the Metabolic Theory of Ecology (MTE) and the Safety Factor hypothesis - offer opposing views on how body size influences it immune defenses. In this study, we compared the immune gene expression of nine primate species to a simulated bacterial infection. We found that larger species mounted a stronger transcriptional immune response, consistent with either the Safety Factor hypothesis or an evolutionary pressure to compensate for and balance the effects expected in the context of the MTE.

evolutionary biology↗