P3.26 Friday, Jan. 6 Establishing the role of vitamin D3 in the fitness of Daphnia spp. exposed to UV radiation CONNELLY, SJ*; TAN, LT; CODY, JC; Rochester Institute of Technology email@example.com
Ultraviolet radiation (UV-R) has been shown to negatively affect exposed organisms through various means. Most can reduce UV-R exposure by behavioral changes, acquisition of UV-filtering pigments and DNA repair processes. Nevertheless, these defenses may be overwhelmed or costly in high UV-R environments, and organisms are known to use available compounds to further decrease their susceptibility. Recent studies of vertebrates have shown significant decreases of UV-R effects with vitamin D. Vitamin D is known to increase the fitness (survival and reproduction) of aquatic microcrustaceans, such as Daphnia. However, the potential for and the pathway by which vitamin D could decrease UV-R effects on Daphnia spp. are unknown. This biochemical study considers the photoprotective potential of vitamin D in Daphnia spp. under UV-A and UV-B conditions in controlled microcosms. Using high performance liquid chromatography (HPLC), we assess the web food transfer of vitamin D3 and metabolites from environment to green algae (Selenastrum capricornutum) to Daphnia spp. under acute and chronic UV-R. Further, we are implementing a novel click-chemistry technique to fluorescently label vitamin D3in vivo. Pin-pointing the vitamin will aid in understanding its utilization mechanism (photoprotection via changes in carapace, increased DNA repair, or some other process). We have demonstrated a significant increase in vitamin D3 and 25-hydroxy vitamin D3 transfer throughout our food web with increased availability of vitamin D3. Further, we have correlated these food web effects to significant increases in the fitness of the species with increasing vitamin D3 under chronic UV conditions. The future directions of this study will identify other metabolites of the vitamin using HPLC and will add additional food web constituents to better track the cycling of the vitamin D3 within our microcosms.