We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
The Effects of Single and Combined Stressors on Daphnids—Enzyme Markers of Physiology and Metabolomics Validate the Impact of Pollution
Summary
Researchers used daphnids to assess the impact of eight chemicals individually and as a mixture, finding that composite mixtures significantly enhanced toxicity and that enzyme markers combined with metabolomics can sensitively detect pollution effects.
The continuous global increase in population and consumption of resources due to human activities has had a significant impact on the environment. Therefore, assessment of environmental exposure to toxic chemicals as well as their impact on biological systems is of significant importance. Freshwater systems are currently under threat and monitored; however, current methods for pollution assessment can neither provide mechanistic insight nor predict adverse effects from complex pollution. Using daphnids as a bioindicator, we assessed the impact in acute exposures of eight individual chemicals and specifically two metals, four pharmaceuticals, a pesticide and a stimulant, and their composite mixture combining phenotypic, biochemical and metabolic markers of physiology. Toxicity levels were in the same order of magnitude and significantly enhanced in the composite mixture. Results from individual chemicals showed distinct biochemical responses for key enzyme activities such as phosphatases, lipase, peptidase, β-galactosidase and glutathione-S-transferase. Following this, a more realistic mixture scenario was assessed with the aforementioned enzyme markers and a metabolomic approach. A clear dose-dependent effect for the composite mixture was validated with enzyme markers of physiology, and the metabolomic analysis verified the effects observed, thus providing a sensitive metrics in metabolite perturbations. Our study highlights that sensitive enzyme markers can be used in advance on the design of metabolic and holistic assays to guide the selection of chemicals and the trajectory of the study, while providing mechanistic insight. In the future this could prove to become a useful tool for understanding and predicting freshwater pollution.
Sign in to start a discussion.
More Papers Like This
Ecological risks of combination of multiple pollutants at environmentally relevant concentrations: Insights from the changes in life history traits, gut microbiota, and transcriptomic responses in Daphnia magna
Researchers exposed Daphnia magna to a combination of 11 pollutants including microplastics, antibiotics, and heavy metals at environmentally relevant ng/L–μg/L concentrations and found significant reductions in heart rate, reproduction, and lifespan, plus gut microbiota and transcriptomic changes — effects that single-pollutant studies would not predict.
Combined effect of microplastics and tire particles on Daphnia magna: Insights from physiological and transcriptomic responses
Researchers investigated the combined effects of microplastics and tire particles on the water flea Daphnia magna, finding that the mixture triggered significant oxidative stress at environmentally relevant concentrations. Transcriptomic analysis revealed upregulation of antioxidant and metabolic stress genes, while energy reserves like glycogen were affected. The study suggests that co-exposure to these common freshwater pollutants may pose greater ecological risks than either particle type alone.
Impacts of microplastics and pesticides on Daphnia
Researchers investigated the combined and individual impacts of microplastics and pesticides on Daphnia magna, a model crustacean widely used in freshwater ecotoxicology, to assess how these co-occurring pollutants affect aquatic ecosystem health. The study examined survival, reproduction, and physiological responses in D. magna exposed to varying concentrations of both stressors under controlled conditions.
Co-exposure of microplastics and 2-methoxy-1,4-naphthoquinone affects Daphnia magna depending on the developmental stage
Researchers studied the combined effects of microplastics and the plant-derived compound 2-methoxy-1,4-naphthoquinone on Daphnia magna, which represents a freshwater ecosystem stress scenario. Co-exposure produced effects that differed from either stressor alone, highlighting the importance of studying pollutant mixtures.
Metabolomic analysis of combined exposure to microplastics and methylmercury in the brackish water flea Diaphanosoma celebensis
Combined exposure of the brackish water flea Diaphanosoma celebensis to microplastics and methylmercury produced metabolomic disruptions greater than either pollutant alone, with the combination altering amino acid metabolism, energy pathways, and oxidative stress markers. The study provides molecular-level evidence that microplastic-mercury co-contamination poses synergistic risks to aquatic invertebrates.