Evaluation of the separate and joint effects of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) contaminants on Microgradus tomcod's Ovarian Cytochrome 19A (CYP19A) gene

Hepatic Cytochrome 1A1 (CYP1A1) and ovarian Cytochrome 19A (CYP19A) gens are recognized as useful biomarkers of exposure of fish to environmental contaminants such as PAHs and PCBs. In this study an experimental laboratory approach by using Microgradus tomcod (Atlantic tomcod) from Huddson River was used to evaluate the additive or interactive effects of PAH and PCB chemicals with respect to their relative merits as bio-indicators. We hypothesize that the mechanistic pathway of PAH and PCB chemicals do not have an additive effect on hepatic CYP1A1 and ovarian CYP19A genes levels of juvenile Atlantic tomcod. Quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR) was used to measure the levels of CYP1A induction in order to detect patterns of CYP1A mRNA levels, a direct measure of cell proliferation. Moreover, the assay was also be used to evaluate the gene encoding the ovarian aromatase enzyme (CYP19A) as biomarker to assess reproductive stress in Atlantic tomcod exposed to pollutants. The assays were implemented be set up as duplex with the threshold cycle (C_T) for the gene of interest. We found that PAH and PCH separately showed a significant change in CYP19A level but they did not show a significant additive change when treated together