Assessment of Cadmium Tolerance and Oxidative Stress Response in Limulus Polyphemus

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Cadmium and other heavy metals are pollutants known to have toxic effects on marine arthropods. However, tolerance to heavy metals has been observed in the American horseshoe crab Limulus polyphemus. We performed experiments to determine whether cadmium induces oxidative stress in horseshoe crabs and whether horseshoe crabs possess an increased oxidative stress response in the presence of cadmium. We performed a 24-hour cadmium exposure on late stage 19 and early stage 20-1 embryos from two different nests to establish the percentage of dead embryos at increasing concentrations. Through Probit analysis of the resulting dose response curve, the LC25 and LC37 doses of cadmium were calculated and used in subsequent experiments. Embryos were exposed to cadmium for 12 and 24 hours periods and then divided for subsequent DNA, RNA, lipid peroxidation, and superoxide dismutase analysis. Lipid peroxidation was assessed with a thiobarbituric acid reactive substances assay and oxidative defense mechanisms by a superoxide dismutase assay. Some of the differences in the levels of lipid peroxidation and superoxide dismutase in treated and untreated embryos may be significant. Further analysis on DNA and RNA will help better determine cadmium's effects on horseshoe crabs and possible mechanisms of heavy metal tolerance.


Eastern Colleges Science Conference, Wilkes-Barre, PA April 2017. C-54. Program retrieved from

Mentored by Suzanne Deschenes.

Award for excellence.

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