Mucosal Lectin Expression in Eastern Oysters Exposed to Physical, Chemical, and Biological Stressors

The eastern oyster (Crassostrea virginica) is a bivalve native to the Eastern and Gulf Coast regions of the United States. They are ecologically beneficial to aquatic communities because of their ability to improve water quality via a filter-feeding mechanism. The oysters also form reefs which provide a crucial habitat for many aquatic invertebrates. The Chesapeake Bay on the Eastern Coast of the United States was once home to an incredibly large population of oysters, but a century's worth of overharvesting and anthropogenic pollution has led to a nearly complete collapse of the oyster population. The experimental research presented herein was undertaken in order to understand the subtle toxic effects of several anthropogenic and natural stressors which may threaten oysters in the Chesapeake Bay region. In the mucus covering the gills of the eastern oyster, lectins are known to be involved in the food particle selection process, and they are also speculated to be involved in mucosal immune responses.;Expression of the lectin CvML was measured via quantitative PCR after exposure of whole, adult oysters to different stressors in three experiments. The first experiment was exposure of oysters to suspended sediment concentrations which closely simulated that of a dredge plume. The second experiment involved exposure of oysters to high levels of phenanthrene, a mixture of two Vibrio pathogens, and a combination of phenanthrene and Vibrio pathogens. In the last experiment, oysters underwent a fasting period before being challenged with phenanthrene or the Vibrio mixture of the previous experiment. The findings of the three separate experiments indicate that expression of CvML was unaltered in any of the tested conditions. In conclusion, expression of CvML is unsuitable as an indicator of subtle toxic effects due to its unaltered state of expression in the tested scenarios.