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Divalent metal content in diet affects severity of manganese toxicity in Drosophila
Zahraa A Ghosn1, Kailynn M Sparks1, Jacob L Spaulding1
1Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
Abstract:
Dysregulation of manganese (Mn) homeostasis is a contributing factor in many neuro-degenerative diseases. Adult Drosophila are sensitive to excessive levels of dietary Mn, dying relatively early, and exhibiting biochemical and mobility changes reminiscent of Parkinsonian conditions. To further study Mn homeostasis in Drosophila, we sought to test lower levels of dietary Mn (5 mM) and noted a striking difference in Canton-S adult survivorship on different food. On a cornmeal diet, Mn-treated flies live only about half as long as untreated siblings. Yet, with the same Mn concentration in a molasses diet, adults survive about 80% as long as untreated siblings, and adults raised on a sucrose-yeast diet are completely insensitive to this low dose of dietary Mn. By manipulating metal ion content in the cornmeal diet, and measuring the metal content in each diet, we traced the difference in lifespan to the levels of calcium and magnesium in the food, suggesting that these ions are involved in Mn uptake and/or use. Based on these findings, it is recommended that the total dietary load of metal ions be considered when assessing Mn toxicity.
Insights
Dietary manganese (Mn) toxicity in fruit flies depends on food composition. Calcium and magnesium levels in diets significantly influence Mn
Area of Science:
- Neuroscience
- Toxicology
- Genetics
Background:
- Manganese (Mn) homeostasis is crucial for preventing neurodegenerative diseases.
- Adult Drosophila melanogaster are susceptible to excessive dietary Mn, showing Parkinsonian-like symptoms.
- Understanding Mn toxicity in model organisms like Drosophila is vital for human health research.
Purpose of the Study:
- To investigate the impact of low-dose dietary manganese (5 mM) on adult Drosophila survivorship.
- To determine how different food compositions affect Mn-induced toxicity.
- To identify dietary factors influencing Mn uptake and toxicity in Drosophila.
Main Methods:
- Feeding adult Canton-S Drosophila with diets containing 5 mM Mn.
- Comparing adult survivorship on cornmeal, molasses, and sucrose-yeast diets.
- Analyzing metal ion content (Mn, Ca, Mg) in different food formulations.
- Correlating dietary metal ion levels with Mn-induced lifespan reduction.
Main Results:
- Cornmeal-based diets exacerbated Mn toxicity, halving fly lifespan.
- Molasses-based diets showed reduced Mn toxicity, with flies surviving 80% as long.
- Sucrose-yeast diets rendered flies insensitive to low-dose Mn exposure.
- Lifespan differences were linked to dietary calcium and magnesium levels.
Conclusions:
- Dietary composition, specifically calcium and magnesium content, critically modulates Mn toxicity in Drosophila.
- These findings suggest that other dietary metal ions influence Mn bioavailability and toxicity.
- Considering the total dietary metal ion load is recommended for assessing Mn toxicity.
