Meeting Abstract
Debris slowly degrades in water into smaller pieces known as microplastics. Microplastics and other man-made substances are harmful in marine and coastal environments, and adversely impact health of aquatic organisms. Cytochrome P450 1A (CYP1A) is a monooxygenase enzyme and commonly used as a toxicological biomarker in tetrapod and teleost fishes. Pinfish Lagodon rhomboides is a highly abundant saltwater species commonly found in the Atlantic coast and Gulf of Mexico. In our study, pinfish were collected by angling from five sampling sites in the Lower Laguna Madre. Fish liver and stomach were collected and preserved in paraformaldehyde for biochemical and immunohistochemical analyses. Three fish were also kept in the laboratory aquariums for three months to serve as control before their liver and stomach were removed. Stomach and intestines were examined under microscope for presence of microplastics. CYP1A expression was determined by immunohistochemical analysis to compare the environmental contaminant level in pinfish liver tissues. Plastic can be found floating on the surface of the water, laying on the beaches and also in the coastline of both South Padre Island and Port Isabel, but microplastics were not found in stomach or intestines of pinfish collected from Lower Laguna Madre. Significantly higher signals of hepatic CYP1A were observed in pinfish collected from Lower Laguna Madre compared to fish in laboratory condition. Collectively, our results suggest that other environmental pollutants, not microplastics, present in the Lower Laguna Madre are impacting the health of marine organisms as seen in the high expression of CYP1A in pinfish liver.
