Efficacy of Amphotericin B in Corneal Preservation Media After Extended Frozen Storage.

PURPOSE: To investigate the antimycotic activity of amphotericin B deoxycholate that has been previously frozen for 28 days before supplementation of Optisol-GS. METHODS: Triplicate Optisol-GS samples were inoculated with 10 colony-forming units (CFU) of Candida albicans. Each set of triplicate cultures was supplemented with 2.5 µg/mL of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at -20°C and thawed, or frozen at -20°C for 4 weeks and thawed. The cultures were stored at 4°C, with aliquots taken at 0, 6, 24, and 72 hours for quantification. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at these time points. RESULTS: Six hours after antifungal supplementation, there was a 1.33 log10 CFU reduction with freshly resuspended amphotericin B, compared with a 1.31 log10 reduction with amphotericin B that was frozen overnight (P = 0.20) and a 1.18 log10 reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). After 72 hours, there was a 2.72 log10 CFU reduction with freshly resuspended amphotericin B, a 2.64 log10 CFU reduction with amphotericin B that was frozen overnight (P = 0.45), and a 2.18 log10 CFU reduction with amphotericin B that was frozen for 4 weeks (P = 0.05). CONCLUSIONS: Previously frozen amphotericin B remains highly effective against C. albicans. Optisol-GS supplemented with 2.5 µg/mL amphotericin B that was frozen for 4 weeks at -20°C resulted in >90% CFU reduction by 6 hours and >99% reduction by 72 hours.

Effects of selenium accumulation on phytotoxicity, herbivory, and pollination ecology in radish (Raphanus sativus L.).

Selenium (Se) has contaminated areas in the western USA where pollination is critical to the functioning of both agricultural and natural ecosystems, yet we know little about how Se can impact pollinators. In a two-year semi-field study, the weedy plant Raphanus sativus (radish) was exposed to three selenate treatments and two pollination treatments to evaluate the effects on pollinator-plant interactions. Honey bee (Apis mellifera L.) pollinators were observed to readily forage on R. sativus for both pollen and nectar despite high floral Se concentrations. Se treatment increased both seed abortion (14%) and decreased plant biomass (8-9%). Herbivory by birds and aphids was reduced on Se-treated plants, indicating a potential reproductive advantage for the plant. Our study sheds light on how pollutants such as Se can impact the pollination ecology of a plant that accumulates even moderate amounts of Se.