Exploring differential gene expression in Striped Bass (Morone saxatilus) in response to mercury exposure
LE3 .A278 2021
Bachelor of Science
Mature Striped Bass, (Morone saxatilis) feed on high trophic level prey, enabling biomagnification of contaminants such as mercury. Mercury is a non-essential heavy metal existing in several forms in aquatic environments and produces various toxic effects in organisms. In this study, the expression of genes coding for antioxidants involved in the oxidative stress response and detoxification, specifically glutathione S-transferase, metallothionein, and thioredoxin reductase in Striped Bass, were examined. Total mercury levels in liver tissues, received in coordination with local fishers in Nova Scotia, were measured using thermal decomposition, gold amalgamation and atomic absorption spectrometry. Real time quantitative polymerase chain reaction and the ∆∆Cq method was used to calculate relative normalized expression of target genes in comparison to the reference, elongation factor 1-alpha.Total mercury levels in liver tissues increased with total length of Striped Bass, indicative of bioaccumulation. No statistically significant relationships were initially observed regarding the expression of target genes and mercury concentration in Striped Bass liver. Metallothionein gene expression exhibited a statistically significant positive relationship with mercury concentration after outlier removal and may serve as a potential biomarker of mercury exposure. This study is the first to show differential expression of novel genes involved in the oxidative stress response and detoxification processes in Striped Bass in response to mercury contamination.
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