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Lowe, M. R.

Publications and source records attributed to Lowe, M. R..

3 recordsLinked to original sources

Exposure to perfluorooctanoic acid accelerates Drosophila melanogaster juvenile development and disrupts mitochondrial metabolism

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with poorly understood sublethal effects on insects. Perfluorooctanoic acid (PFOA), one of the most widely distributed legacy PFAS is increasingly recognized for altering organismal physiology beyond traditional toxicity endpoints. Here, we use the fruit fly Drosophila melanogaster as a model to examine how PFOA exposure during larval (juvenile) development reshapes insect life-history progression and metabolic homeostasis. Our studies reveal that at environmentally relevant concentrations (nM to low {micro}M), PFOA induces precocious expression of developmentally-regulated genes and leads to metabolic changes that persist into adulthood. At higher concentrations used to probe mechanism, PFOA accelerates larval development, disrupts mitochondrial membrane potential, and increases whole-organism metabolic heat production - results that suggest altered mitochondrial energetic efficiency. Consistent with this tradeoff, PFOA-exposed larvae that develop faster under permissive conditions exhibit heightened sensitivity to environmental stressors, including elevated temperature and reduced food hydration. Together, these findings demonstrate that PFOA disrupts metabolic and developmental processes in a dose- and context-dependent manner, highlighting sublethal effects that may influence insect resilience under environmental stress. SYNOPSIS STATEMENTHere we describe how PFOA alters the growth, development, and metabolism of the fruit fly Drosophila melanogaster. Specifically, we find that PFOA accelerates Drosophila juvenile growth while also rendering exposed larvae sensitive to environmental stress. These observations suggest that widespread PFOA contamination may impair the developmental fitness of insect populations.

pharmacology and toxicology↗

Conserved Molecular Responses to Arsenite Exposure in Drosophila melanogaster

Arsenic exposure is a pervasive global health threat strongly associated with increased risk of morbidities such as diabetes, cardiovascular disease, and cancer. Despite extensive studies describing the dangers of arsenic exposure, the molecular initiating events that link arsenic to chronic disease onset and progression remain poorly defined. To address this knowledge gap, we combined time-resolved transcriptomic and metabolomic profiling of adult Drosophila melanogaster exposed to sodium (meta) arsenite (NaAsO2). We uncovered coordinated, dose-dependent shifts in gene expression and metabolite abundance that activate canonical detoxification pathways and mirror arsenic-associated disease signatures in humans. Notably, flies rapidly upregulated heatshock and xenobiotic response gene networks, followed by biomarkers characteristic of diabetic states (elevated glucose, lactate, and methylglyoxal, for example). These findings reveal conserved molecular pathways that couple arsenic exposure to metabolic dysfunction and establish Drosophila as a powerful whole-organism model for identifying early biomarkers and mechanistic drivers of arsenic-induced disease phenotypes.

pharmacology and toxicology↗

Effect of copper mill waste material on benthic invertebrates and zooplankton diversity and abundance in Lake Superior beaches

From 1900 to 1932 a copper (Cu) mill operated near Gay, Michigan, along the eastern shore of the Keweenaw Peninsula (Lake Superior, Michigan) and discharged waste material (stamp sands [SS]) to a nearby beach. These SS escaped containment structures and have been redeposited by wave action along the beaches in northern Grand Traverse Bay and onto Buffalo Reef, an important spawning area for native fish. Newly hatched fish move into nearby beach habitats where they grow during their first summer. Juvenile fish initially consume zooplankton before switching to benthic invertebrates once they are large enough. SS contain metals (especially Cu) that are toxic to many invertebrate taxa, and studies have observed few benthic taxa in areas covered by SS. We sampled the invertebrate community from four Lake Whitefish nursery areas: one near Buffalo Reef with high SS, one south of the Traverse River with moderate SS, one in nearby Little Traverse Bay with little SS, and a beach [~]58 km away with no SS (Big Bay). We also resampled the benthos at sites that had been sampled as part of an earlier Grand Traverse Bay study. Buffalo Reef (high SS) had fewer benthic taxa, and less density of several taxa than Little Traverse Bay (little SS), especially benthic copepods. All beaches had comparable zooplankton diversity, but the abundance was [~]2 orders of magnitude lower at Buffalo Reef (high SS) than other beaches. Cu and several other metals were elevated at beaches with more SS. We found support for associations between benthic density and diversity with depth (positive effect) and Cu concentration (negative effect). Cu concentration was a better predictor of declines in benthic invertebrate abundance and diversity than SS. We also observed that the relationship between Cu concentration and SS was non-linear, and highly variable. For example, 149 mg Cu/kg dry weight sediment is a consensus toxicity threshold used in the literature, but the prediction interval around that concentration from our model is 26-851 mg Cu/kg dry weight. A better predictive model of this relationship would be beneficial to develop to understand what level of SS reduction would prevent Cu impacts on invertebrates.

ecology↗