Meeting Abstract

50.2  Thursday, Jan. 5  The photoprotective properties of vitamin D in Daphnia spp. WALLING, KM; CARRERA, JV; CODY, JC; TAN, LT; CONNELLY, SJ*; Rochester Institute of Technology kmw9325@rit.edu

Environmental variability significantly impacts the adaptations of natural populations. Increased levels of ultraviolet radiation (UVR) at earth’s surface have been shown to have a wide range of effects on organisms, from no impact to lethality. Recent studies have shown benefits of vitamin D to individuals, primarily vertebrates, exposed to increased levels of solar radiation. Daphnia spp. are especially sensitive to environmental stressors, particularly UVR, and their rapid adaptation to these stressors is crucial. It is known that Vitamin D can increase the fitness (survival and reproduction) of Daphnia spp. This research focuses on the impact of UVR on freshwater microcrustacean, Daphnia spp., and the potential protective properties of vitamin D3 in this genus. It is hypothesized that vitamin D3, or its primary metabolite (25-hydroxyvitamin(OH)D3,) will also have photoprotective properties in the Daphnia. Juvenile (pre-reproductive) Daphnia spp. were exposed to vitamin D3 (0, 5, or 10mg / 100mL) and UV-A (320-400nm; 6.912 kJ/ m2) for 72 hours, methanol extracted, and analyzed using High Performance Liquid Chromatography (HPLC) to quantify vitamin D3 and 25(OH)D3 in the Daphnia, the algae (Selenastrum capricornutum), and the freshwater synthetic growth media. The quantity of vitamin D3 and 25(OH)D3 in the Daphnia were then correlated to their overall fitness (survival and total reproduction) in a separate experiment. Increased concentrations of vitamin D3 directly correlate with increased survival of Daphnia spp. with UV-A exposure, but not clearly with reproduction. Studies continue to determine if other vitamin D3 metabolites may play a greater role in the fitness of the Daphnia spp. with changes in UVR. Further, food web studies of various algae and Daphnia spp. are being investigated to determine the photosensitivity and photoprotective properties of the vitamin D3 in natural systems.