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Updated: Jun 19, 2026

Analysis of Oxidative Stress in Zebrafish Embryos
Published on: July 7, 2014
DNA Methylation and Oxidative Stress in a Fish from an Area of the Amazon Historically Impacted by Anthropogenic
Douglas Dos Santos Marcelino1, Luana Beatriz Sales Pinon1, Yure Jefferson da Cruz do Nascimento2,3
1Laboratório de Genética e Biologia Celular, Center for Advanced Biodiversity Studies, Institute of Biological Sciences, Federal University of Pará, Belém, PA, 66075-750, Brazil.
Abstract:
The Amazon hosts the world's richest biodiversity but faces increasing anthropogenic pressures that threaten ecosystem health. To evaluate aquatic pollution impacts at molecular and biochemical levels, we analyzed DNA methylation, gene expression and oxidative stress biomarkers in gill, liver, and muscle tissues of the fish Geophagus surinamensis collected from Breves (reference), Abaetetuba, and Barcarena (industrial area). Individuals from Abaetetuba exhibited the strongest responses, with global hypermethylation in liver and muscle, decreased expression of dnmt1, dnmt3b, and tet2, and altered GST and LPO levels. Barcarena samples also showed increased methylation but milder transcriptional and biochemical changes, likely due to contaminant dispersion by Pará River hydrodynamics. The liver was the most responsive organ, reflecting its detoxification role. Overall, these findings demonstrate that pollution in Barcarena significantly affects nearby aquatic environments, highlighting the value of epigenetic and oxidative stress biomarkers as sensitive tools for environmental monitoring.
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