Environmental Sensing, Metabolic Response, and Regulatory Networks in the Respiratory Versatile Bacterium Shewanella oneidensis MR-1
Sponsor: DOE Office of Biological and Environmental Research; PNNL's Biomolecular Sciences Initiative
Contacts: Margaret Romine, Alex Beliaev, and Jim Fredrickson
Shewanella oneidensis MR-1 is a motile facultative bacterium with remarkable metabolic versatility in regards to electron acceptor utilization; it can utilize O2, nitrate, fumarate, Mn, Fe, and S0 as terminal electron acceptors during respiration. This versatility allows MR-1 to efficiently compete for resources in environments where electron acceptor type and concentration fluctuate in space and time. In spite of considerable effort, the details of MR-1's electron transport system and the mechanisms by which it reduces metals and radionuclides remain unclear. The entire genome sequence of MR-1 has been determined and high throughput methods for measuring gene expression are available or being developed, including mass spec-based proteome analyses developed at PNNL. Although powerful, DNA array and proteome analyses must be tightly coupled with other approaches to effectively reveal the molecular details of how MR-1 functions in, and responds to, its environment. We are investigating gene regulatory and metabolic networks in MR-1 using a combination of techniques including high-throughput proteomics and DNA microarrays; gene function (mutagenesis); protein localization (transmission electron, fluorescence, and AFM-enhanced two-photon confocal microscopy); and continuous culture based techniques. Although the initial research will be focused on specific systems and processes, including electron transport to metals and adhesion to surfaces, we expect that the information and approaches developed under this project will provide the foundation for a more comprehensive understanding of the biological functioning of MR-1. This project is also part of a larger collaborative effort, known as the Shewanella Federation, to investigate the detailed functions of Shewanella.