Thrust Area I: Physiology of metal-reducing strains of Shewanella.
EMSL Project ID
13302
Abstract
A multidisciplinary team of scientists is investigating the mechanisms of electron transfer from metal-reducing bacterial to Fe oxide surface as part of a PNNL/DOE-BER Grand Challenge in Biogeochemistry (BGC) being led by Drs. Zachara and Fredrickson of PNNL. Dr. Kenneth Nealson is a leading expert on the physiology of dissimilatory metal reducing bacteria and was responsible for the initial isolation and characterization of Shewanella oneidensis. Dr. Nealson has contributed to the planning phase of the grand challenge and was a member of the Advisory Committee. His continued participation and research efforts in the BGC are anticipated to provide key information regarding the physiology of metal-reducing strains of Shewanella. To complete the objectives of this project, the following tasks need to be conducted at the University of Southern California under the direction of Dr. Nealson. These tasks include:1. Characterization of the metal-reducing phenotype of the various strains of metal-reducing Shewanella whose genomes have been or are in the process of being sequenced. These include, but are not limited to, S. oneidensis MR-1, S. baltica, S. putrefaciens CN32 and 200, S. frigidimarina, Shewanella sp. strain PV-4, and S. amazonensis. S. denitrificans has been reported in the literature to be unable to reduce Fe(III) but should be included for comparative purposes. Consider including metal-reducing members of the Geobacteriaceae, Desulfovibrio and Desulfotomaculum in these analyses for comparison. The analyses should include growth on & reduction of various electron acceptors under anaerobic conditions including a series of standard mineral phases as agreed upon by the BGC team. The cultivation of Shewanella for these experiments will be done in a manner consistent with approaches agreed upon in advance by the BGC team to allow for maximum comparability of results between different laboratories. Y. Gorby (PNNL) is serving as coordinator for the BGC cultivation efforts and should be the point of contact for cultivation.
2. Characterization of proteins bound to mineral phases. Initial work has begun with regard to mineral phases and their attached proteins from Shewanella oneidensis MR-1, and we propose to continue this work, looking at the ability of various strains to produce proteins with affinity towards various oxidized forms of iron and manganese, and perhaps other metals key to the DOE effort. This work, in particular, will utilize the facilities at the EMSL, working to characterize the proteins, their attached metals, and provide preliminary amino acid sequence analysis so that genes can be identified.
3. Initial characterization via VSI of the ability of various strains to reduce thin films of Mn and Fe oxides. This work will involve the visualization of cells as they interact with, and attach to the metal oxide surfaces.
Project Details
Project type
Grand Challenge
Start Date
2007-08-23
End Date
2006-05-25
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members