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
                                            Reardon, Catherine

                                                         - *Kate*item
                                            MAGNUSON, TIMOTHY - Idaho State Universityitem
                                            BOYD, ERIC - Montana State Universityitem
                                            LEAVITT, WILLIAM - Harvard Universityitem
                                            REED, DAVID - Idaho National Laboratoryitem
                                            GEESEY, GILL - Montana State University
  Submitted to: Microbial Ecology
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 10/1/2013
                                    Publication  Date: 11/6/2013
                                    Citation: Reardon, C.L., Magnuson, T.S., Boyd, E.S., Leavitt, W.D., Reed, D.W., Geesey, G.G. 2013. Hydrogenase activity of mineral-associated and suspended populations of Desulfovibrio Desulfuricans Essex 6. Microbial Ecology. 67(2):318-326.Interpretive Summary: Sulfate reducing bacteria (SRB) are a diverse group of microbes that have significant industrial and environmental impacts. SRB produce sulfide from the metabolism of sulfate. Sulfide, which is highly corrosive, not only contributes to the biocorrosion of metals but affects the type and solubility of minerals and metals in the environment. Sulfide reacts rapidly with iron to form ferrous sulfide minerals. Several factors control the type and stability of the ferrous sulfides that are formed. These factors include the concentrations of sulfide and soluble iron, the pH, and redox potential, all which can be affected by microbial activity. SRB commonly grow on particle surfaces. The ferrous sulfides that are formed by cells attached to a mineral surface are different than those formed by cells growing in a suspension. In order to identify why the ferrous sulfides are different, we analyzed the activity of a cellular enzyme that can potentially influence the conditions near the cell. The enzyme hydrogenase catalyzes reversible reaction H2 ' 2H+ + 2e- and can transfer energy or electrons directly to metals. The hydrogenase activity of the SRB Desulfovibrio desulfuricans strain Essex 6 was compared when cells were cultured under sulfate-reducing (sulfide-producing) or pyruvate fermenting (non-sulfide-producing) conditions in the presence or absence of hematite, an iron oxide mineral. The hydrogenase activity of cells attached to the hematite surface was
                                Technical Abstract: The interactions between sulfate-reducing microorganisms and iron oxides influence a number of important redox-sensitive biogeochemical processes including the formation of iron sulfides. Enzymes, such as hydrogenase which catalyze the reversible oxidation of molecular hydrogen, are known to mediate electron transfer to metals and may contribute to the formation and speciation of ferrous sulfide formed at the cell-mineral interface. The present study describes the effect of growth on a hematite surface on whole cell hydrogenase activity associated with different metabolic pathways in Desulfovibrio desulfuricans strain Essex 6. Hematite-associated cells exhibited significantly greater hydrogenase activity than suspended populations during sulfate respiration but not pyruvate fermentation. The enhanced activity of the hematite-associated, sulfate-grown cells appears to be dependent on iron availability rather than a general response to surface attachment since the activity of glass-associated cells did not differ from that of suspended populations. Hydrogenase activity of pyruvate-fermenting cells was stimulated by addition of iron as soluble Fe(II)Cl2 and, in the absence of added iron, both sulfate-reducing and pyruvate-fermenting cells displayed similar rates of hydrogenase activity. These data suggest that iron exerts a stronger influence on whole cell hydrogenase activity than either metabolic pathway or surface-associated growth. The localization of hydrogenase to the cell envelope and the enhanced activity at the mineral surface in sulfate-reducing cells may contribute to the speciation of iron sulfides formed under these different growth phases.


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