U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Columbia Plateau Conservation Research Center: Pendleton, OR
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    Careers


        


                    Related TopicsSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Pacific West Area Pendleton, Oregon Columbia Plateau Conservation Research Center Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            MITCHELL, ANDY - Montana State Universityitem
                                            PETERSON, LUKE - Montana State Universityitem
                                            Reardon, Catherine

                                                         - *Kate*item
                                            REED, S - Pacific Northwest National Laboratoryitem
                                            CULLEY, D - Pacific Northwest National Laboratoryitem
                                            ROMINE, M - Pacific Northwest National Laboratoryitem
                                            GEESEY, GILL - Montana State University
  Submitted to: Geobiology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 1/19/2012
                                    Publication  Date: 2/23/2012
                                    Citation: Mitchell, A.C., Peterson, L., Reardon, C.L., Reed, S.B., Culley, D.E., Romine, M.F., Geesey, G.G. 2012. Role of outer membrane c-type cytochromes MtrC and OmcA in Shewanella oneidensis MR-1 cell production, accumulation and detachment during respiration on hematite. Geobiology. 10, 355-370.Interpretive Summary: Shewanella oneidensis MR-1 is a model bacterium for study of microbial metal reduction.  S. oneidensis MR-1 is able to respire crystalline iron oxides such as hematite using the outer membrane cytochromes OmcA and MtrC for electron transfer to the mineral.  In this study, we investigated how the cytochromes affect biofilm formation on hematite when using the mineral for respiration.  MtrC but not OmcA is required for growth on the mineral surface however OmcA was required for efficient electron transfer once the biofilm had developed.  These results indicate that the two cytochromes have different roles in the respiration of hematite.
                                Technical Abstract: The iron-reducing bacterium Shewanella oneidensis MR-1 has the capacity to contribute to iron cycling over the long term by respiring on crystalline iron oxides such as hematite when poorly crystalline phases are depleted. The ability of outer membrane cytochromes OmcA and MtrC of MR-1 to bind to and transfer electrons to hematite has led to the suggestion that they function as terminal reductases when this mineral is used as a respiratory substrate. Differences in their redox behavior and hematite-binding properties, however, indicate that they play different roles in the electron transfer reaction. Here, we investigated how these differences in cytochrome behavior with respect to hematite affected biofilm development when the mineral served as terminal electron acceptor (TEA). Upon attachment to hematite, cells of the wild-type (WT) strain as well as those of a 'omcA mutant but not those of a 'mtrC mutant replicated and accumulated on the mineral surface. The results indicate that MtrC but not OmcA is required for growth when this mineral serves as TEA. While an OmcA deficiency did not impede cell replication and accumulation on hematite prior to achievement of a maximum surface cell density comparable to that established by WT cells, OmcA was required for efficient electron transfer and cell attachment to hematite once maximum surface cell density was achieved. OmcA may therefore play a role in overcoming barriers to electron transfer and cell attachment to hematite imposed by reductive dissolution of the mineral surface from cell respiration associated with achievement of high surface cell densities.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov