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Experimental Protocol for Using Drosophila As an Invertebrate Model System for Toxicity Testing in the Laboratory
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Drosophila melanogaster - an embryonic model for studying behavioral and biochemical effects of manganese exposure
Ana Paula Lausmann Ternes1, Ana Paula Zemolin2, Litiele Cezar da Cruz2
1Centro Interdisciplinar de Pesquisa em Biotecnologia (CIP/BIOTEC), Universidade Federal do Pampa, Campus São Gabriel, RS, 97300 000, Brasil.
Abstract:
Embryonic animals are especially susceptible to metal exposure. Manganese (Mn) is an essential element, but in excess it can induce toxicity. In this study we used Drosophila melanogaster as an embryonic model to investigate biochemical and behavioral alterations due to Mn exposure. Flies were treated with standard medium supplemented with MnCl2 at 0.1 mM, 0.5 mM or 1 mM from the egg to the adult stage. At 0.5 mM and 1 mM Mn, newly ecloded flies showed significantly enhanced locomotor activity when assessed by negative geotaxis behavior. In addition, a significant increase in Mn levels (p < 0.0001) was observed, while Ca, Fe, Cu, Zn and S levels were significantly decreased. A significant drop in cell viability occurred in flies exposed to 1 mM Mn. There was also an induction of reactive oxygen species at 0.5 mM and 1 mM Mn (p < 0.05). At 1 mM, Mn increased Catalase (p < 0.005), Superoxide Dismutase (p < 0.005) and Hsp83 (p < 0.0001) mRNA expression, without altering Catalase or Superoxide Dismutase activity; the activity of Thioredoxin reductase and Glutatione-S-transferase enzymes was increased. Mn treatment did not alter ERK or JNK1/2 phosphorylation, but at 1 mM caused an inhibition of p38(MAPK) phosphorylation. Together these data suggest mechanisms of adaptation in the fly response to Mn exposure in embryonic life.
Insights
Embryonic manganese (Mn) exposure in Drosophila melanogaster increased locomotor activity and altered essential mineral levels. The study suggests adaptive mechanisms in flies responding to excess Mn during development.
Area of Science:
- Developmental toxicology
- Neurobiology
- Environmental health
Background:
- Embryonic development is a critical window for susceptibility to environmental toxicants.
- Manganese (Mn) is an essential trace element, but elevated levels can cause neurotoxicity.
- Understanding Mn's impact on developing organisms is crucial for public health.
Purpose of the Study:
- To investigate the biochemical and behavioral effects of embryonic manganese exposure in Drosophila melanogaster.
- To elucidate potential adaptive mechanisms in response to developmental Mn exposure.
Main Methods:
- Drosophila melanogaster embryos were exposed to varying concentrations of manganese chloride (MnCl2) from egg to adult stages.
- Locomotor activity was assessed using negative geotaxis behavior.
- Biochemical analyses included elemental profiling, cell viability assays, reactive oxygen species (ROS) detection, and gene/protein expression analysis (Catalase, Superoxide Dismutase, Hsp83, MAPK pathways).
Main Results:
- Embryonic Mn exposure (0.5 mM and 1 mM) significantly enhanced locomotor activity and increased Mn levels in adult flies.
- Exposure led to decreased levels of essential minerals (Ca, Fe, Cu, Zn, S) and reduced cell viability at 1 mM Mn.
- Increased ROS production, altered gene expression (Catalase, SOD, Hsp83), enhanced enzyme activity (Thioredoxin reductase, Glutathione-S-transferase), and inhibited p38 MAPK phosphorylation were observed.
Conclusions:
- Developmental exposure to excess manganese induces significant behavioral and biochemical changes in Drosophila.
- The observed alterations suggest the activation of adaptive stress responses, including antioxidant defenses and mineral dysregulation.
- These findings highlight the complex interplay between essential metal exposure and developmental processes, potentially involving MAPK signaling pathways.
