Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The release of uranium from waste repositories into the ground water and surrounding soil can have adverse effects on the biomes of affected sites. The bioavailability and chemical toxicity of U(VI) species, which are the most prevalent in oxic environments of soils and water bodies, can pose serious threats as they are transferred through the food chain. Despite remediation strategies employing the cultivation of crop plants to sequester uranium, little is known of the mechanisms used by plants in processing the uranium species that they encounter. The aim of this research therefore has been to shed light on the pathways involved in the uptake and processing of uranium by plant cells, using the undifferentiated tobacco BY-2 cells as model plant cells. Former experiments showing increases in the cytoplasmic glutathione pools upon exposure of Brassica napus cell cultures to uranium have led us to the hypothesis that tobacco cells are able to reduce U(VI) to U(IV). This research describes a novel method of exposing BY-2 cells to U(VI) in phosphate deficient medium, which maintains relatively high cell viability under phosphate deficient conditions, and reveals differentially expressed proteins in the presence of uranium. Uranium-spiked culture medium was seen to affect the uptake of trace elements and minerals as well as show changes in the profiles of polyacrylamide-resolved proteins. Proteomics is being used to identify candidate proteins involved in the processing of uranium by the cells and microscopic visualization techniques are utilized to confirm these pathways and mechanisms.

Acknowledgments: This work is funded by the German Federal Ministry of Education and Research under the contract number 02NUK051B.