Biology subjects

Monroe, J.

Publications and source records attributed to Monroe, J..

4 recordsLinked to original sources

bioRxiv2026

The Metabolome of Drosophila Reveals Exercise-Induced Stress and Anti-Inflammatory Response

Exercise is a known remedy for metabolic disorders, including obesity and type II diabetes. In humans and some model organisms, exercise is classified into different types and intensities based on the mode of exercise and the devices used. Since Drosophila has emerged as a model for exercise research, several devices have been developed for exercise training. These devices vary in mechanisms of operation; for example, the Power Tower (PT) uses a repeated drop-and-hit mechanism, and the TreadWheel (TW) uses end-over-end rotation. This variation in mechanisms that trigger the negative geotaxis of flies could impact exercise outcomes, and it remains unclear how this variation drives the response of flies to exercise training. Stress is a known response to exercise in humans and mice. Stress in Drosophila can be induced by various conditions, including heat, cold, chemical exposure, and other environmental stressors, but there is little information on exercise-induced stress. It is also unclear whether different devices elicit distinct stress responses or whether the exercise-induced stress response is similar to other stress responses (e.g., thermal, chemical). To explore the effects of device, sex, and genotype on multiple metabolic pathways, we used an untargeted metabolomics approach to further elucidate the molecular mechanisms of exercise. As no studies have directly examined the exercise metabolome of Drosophila, this study is the first to explore the metabolome of flies post-exercise. Our results revealed that exercising on different devices elicits varying responses and reshapes the metabolome of flies. We also identified specific small compounds that may be linked to stress and inflammatory response more in the PT-exercised flies than in the TW-exercised flies. Overall, the exercise device effect interacted with sex effect and genotype, such that male and female flies have different metabolite compositions post-exercise on TW and PT.

Molecular Biology↗

bioRxiv2025

Development of a network formation assay for developmental neurotoxicity hazard screening using 3D human iPSC derived BrainSpheres

Exposure of the developing brain to environmental neurotoxicants can result in permanent alterations in structure and/or function. To investigate the effects of chemical exposures on neurodevelopment, the human induced-pluripotent stem cell (iPSC)-derived neural BrainSphere model has been utilized due to its ability to form mature neuronal populations and exhibit spontaneous electrical activity. To model network formation for developmental neurotoxicity screening, developing BrainSpheres were plated on high-density microelectrode arrays (hdMEA) three weeks after beginning differentiation. Starting two days post-plating, BrainSpheres were treated three times per week with compounds known to disrupt in vitro network formation (i.e. assay positive controls; loperamide, dieldrin and deltamethrin), or with an assay negative control, glyphosate, expected to have no effect. For 29 days, BrainSphere activity was recorded to measure neural network activity, general activity, and features of action potential propagation. Concentration-dependent disruption in neural network formation was observed for positive controls at concentrations below cytotoxicity. Dieldrin, deltamethrin, and loperamide exposure disrupted several features of general activity, neural network formation, and action potential propagation. BrainSpheres on hdMEAs detected chemically induced perturbations in neural network formation and may represent a valuable complex in vitro model useful for developmental neurotoxicity screening.

neuroscience↗

bioRxiv2024

The pseudoenzyme β-amylase9 from Arabidopsis binds to and enhances the activity of α-amylase3: A possible mechanism to promote stress-induced starch degradation

Starch accumulation in plant tissues provides an important carbon source at night and for regrowth after periods of dormancy and in times of stress. Both [a]- and {beta}-amylases (AMYs and BAMs, respectively) catalyze starch hydrolysis, but their functional roles are unclear. Moreover, the presence of catalytically inactive amylases that show starch excess phenotypes when deleted presents an interesting series of questions on how starch degradation is regulated. Plants lacking one of these catalytically inactive {beta}-amylases, BAM9, were shown to have enhanced starch accumulation when combined with mutations in BAM1 and BAM3, the primary starch degrading BAMs in response to stress and at night, respectively. Importantly, BAM9 has been reported to be transcriptionally induced by stress through activation of SnRK1. Using yeast two-hybrid experiments, we identified the plastid-localized AMY3 as a potential interaction partner for BAM9. We found that BAM9 interacted with AMY3 in vitro and that BAM9 enhances AMY3 activity 3-fold. Modeling of the AMY3-BAM9 complex revealed a previously undescribed N-terminal structural feature in AMY3 that we call the alpha-alpha hairpin that could serve as a potential interaction site. Additionally, AMY3 lacking the alpha-alpha hairpin is unaffected by BAM9. Structural analysis of AMY3 showed that it can form a homodimer in solution and that BAM9 appears to replace one of the AMY3 monomers to form a heterodimer. Collectively these data suggest that BAM9 is a pseudoamylase that activates AMY3 in response to cellular stress, possibly facilitating starch degradation to provide an additional energy source for stress recovery.

biochemistry↗

bioRxiv2023

Heterotypic responses against nsp12/nsp13 from prior SARS-CoV-2 infection associates with lower subsequent endemic coronavirus incidence

Immune responses from prior SARS-CoV-2 infection and COVID-19 vaccination do not prevent re-infections and may not protect against future novel coronaviruses (CoVs). We examined the incidence of and immune differences against human endemic CoVs (eCoV) as a proxy for response against future emerging CoVs. Assessment was among those with known SARS-CoV-2 infection, COVID-19 vaccination but no documented SARS-CoV-2 infection, or neither exposure. Retrospective cohort analyses suggest that prior SARS-CoV-2 infection, but not COVID-19 vaccination alone, protects against subsequent symptomatic eCoV infection. CD8+ T cell responses to the non-structural eCoV proteins, nsp12 and nsp13, were significantly higher in individuals with previous SARS-CoV-2 infection as compared to the other groups. The three groups had similar cellular responses against the eCoV spike and nucleocapsid, and those with prior spike exposure had lower eCoV-directed neutralizing antibodies. Incorporation of non-structural viral antigens in a future pan-CoV vaccine may improve protection against future heterologous CoV infections.

immunology↗