Diploma- & Master thesis
Studies on the isolation and characterization of plant cell metabolites after exposure of cells to uranium(VI) and europium(III) and spectroscopic studies on the interaction of uranium(VI) and europium(III) with relevant model ligands for plant cells
Dr. Susanne Sachs, Dr. Henry Moll
From a radio-ecological point of view, the interaction of radionuclides with plants is interesting both in regard to soil remediation of radioactively contaminated areas such as legacies of former uranium mining and for the safety assessment of repositories for radioactive waste. The molecular mechanisms behind the interaction of radionuclides with plants are not yet completeley understood. Furthermore, the interaction of radionuclides with plants is often only described by transfer factors.
For a comprehensive understanding of the interaction mechanisms of radionuclides with plants, the interaction of uranium(VI) and europium(III) (analogue for trivalent actinides) with Brassica napus suspension cell cultures will be investigated. Based on previous investigations, this study deals with the isolation and characterization of plant cell metabolites. These substances are formed by plant cells as a stress response to heavy metal or radionuclide exposure. Formed metabolites are then released into the surrounding medium. The heavy metal uptake of the cells is examined using ICP-MS and correlated with cell viability. The isolation and enrichment of the metabolites from the cell culture media is realized by the means of solid phase extraction. The eluates obtained are characterized by HPLC and mass spectrometry. Additionaly cryogenic TRLFS will be used as a versatile tool to characterize U(VI) and Eu(III) complexes with model compounds, in order to identify possible U(VI)/Eu(III) metabolite species.
The work is part of the project "Trans-LARA" (Transport and transfer behaviour of long-lived radionuclides along the pathway groundwater - soil - surface - plant under consideration of long-term climatic changes), which is funded by the Federal Ministry of Education and Research under contract number 02NUK051B.