Lawrence Berkeley National Laboratory

The microorganism Desulfovibrio vulgaris Hildenborough , because of its metabolic versatility, its ability to remediate metals and radionuclides, and the ease with which it can be maintained in culture is of particular interest to the DOE. However, the effective implementation of remediation strategies and the use of natural attenuation for the cleanup of DOE sites is dependant upon understanding critical chemical, physical, and biological processes. Thus, an understanding of regulatory mechanisms and cellular responses to different environmental factors affecting the metal remediation activity in situ is of great importance. However, understanding the genome, transcriptome, and proteome may not be enough to fully characterize the pathways involved in bioremediation. For example, the proteome cannot be completely predicted from the transcriptome because of post-translational modifications, some of which may occur slowly, while others occur rapidly irrespective of the rate of protein synthesis. Furthermore, transcriptome changes can be significantly slower than changes to the proteome. An approach based solely on transcriptomics may also be inadequate, since there are many genes that are not under transcriptional control. Whereas the metabolome is further down the line from gene function and so reflects more closely the activities of a cell at the functional level. Capillary electrophoresis and time of flight mass spectrometry (CE-TOFMS) is generally considered a promising technique for metabolome analysis due to its high separation efficiency and accurate mass determination with low sample volume requirements. We have utilized novel CE-TOFMS methods for the detection and identification of anionic and cationic metabolites within D. vulgaris at mid-log phase. This approach has proved successful in determining most types of compound, including amino acids, carbohydrate derivatives, coenzyme As, nucleosides, nucleotides and organic acids.