Differential Cellular Response to Mercury in Non-Farmed Fish Species Based on Mitochondrial DNA Copy Number Variation
Marta Giuga1,2, Venera Ferrito1, Giada Santa Calogero1
1Department of Biological, Geological and Environmental Sciences, Section of Animal Biology "M. La Greca", University of Catania, Via Androne 81, 95124 Catania, Italy.
Biology
|September 28, 2024
Summary
Mercury contamination threatens marine life. This study shows changes in mitochondrial DNA copy number (mtDNAcn) in fish can indicate oxidative stress, serving as an early warning for aquatic ecosystem health.
Area of Science:
- Environmental toxicology
- Marine biology
- Molecular ecology
Background:
- Mercury's persistence and pro-oxidant effects pose significant threats to marine ecosystems.
- Mitochondrial DNA (mtDNA) is vulnerable to reactive oxygen species (ROS)-induced damage.
- Understanding biomarkers for oxidative stress in aquatic organisms is crucial for environmental monitoring.
Purpose of the Study:
- To validate the variation in mitochondrial DNA copy number (mtDNAcn) as a biomarker of oxidative stress in fish from contaminated marine environments.
- To assess the impact of mercury bioaccumulation on mtDNAcn in selected Mediterranean fish species.
Main Methods:
- Quantitative PCR (qPCR) was used to measure relative mtDNAcn in three fish species: *Mullus barbatus*, *Diplodus annularis*, and *Pagellus erythrinus*.
- Fish were collected from Augusta Bay (high mercury contamination) and a control site in Sicily.
- Mercury bioaccumulation levels were compared between sites and correlated with mtDNAcn variations.
Main Results:
- *Mullus barbatus* and *Pagellus erythrinus* from Augusta Bay exhibited significantly reduced mtDNAcn compared to control groups.
- *Diplodus annularis* showed an increase in mtDNAcn in the contaminated area, indicating species-specific responses.
- Results suggest mercury exposure alters mitochondrial dynamics, potentially through fission-fusion pathways.
Conclusions:
- Variation in mtDNAcn is a promising biomarker for detecting early-warning, stress-related impacts in aquatic systems.
- mtDNAcn changes can reflect species-specific resilience and responses to environmental toxicants like mercury.
- This approach offers a valuable tool for assessing the health of marine environments affected by pollution.
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