A5034042879- Microbial Fuel Cells and Bioremediation
- Radioactive element chemistry and processing
- Geochemistry and Elemental Analysis
- Microbial Community Ecology and Physiology
- Iron oxide chemistry and applications
- Electrochemical Analysis and Applications
- Hydrocarbon exploration and reservoir analysis
- Radioactive contamination and transfer
- Electron and X-Ray Spectroscopy Techniques
- Minerals Flotation and Separation Techniques
- Metal Extraction and Bioleaching
- Genomics and Phylogenetic Studies
- Electrochemical sensors and biosensors
- Advanced X-ray Imaging Techniques
- Ion-surface interactions and analysis
- Air Quality and Health Impacts
- Radioactivity and Radon Measurements
- Advanced Proteomics Techniques and Applications
- Biosensors and Analytical Detection
- Bacterial Identification and Susceptibility Testing
- Diatoms and Algae Research
- Advanced X-ray and CT Imaging
- Microfluidic and Capillary Electrophoresis Applications
- Advanced Materials Characterization Techniques
- Analytical chemistry methods development
Pacific Northwest National Laboratory
2010-2020
Richland College
2014-2020
Wildlife Trusts
2015
ZRT Laboratory
2012
Argonne National Laboratory
2011
École Polytechnique Fédérale de Lausanne
2009
Stanford Synchrotron Radiation Lightsource
2009
Washington State University
2008
J. Craig Venter Institute
2008
University of Idaho
2001
BETA-Lactamases (EC. 3.5.2.6) from strains of Gram-negative bacteria have been studied using analytical isoelectric focusing. This permits a visual comparison the patterns beta-lactamase bands produced by enzymes different organisms. Purification crude intracellular preparations is unnecessary and technique sufficiently sensitive to demonstrate in mutants previously reported lack enzyme. R that not distinguished one another biochemically or immunologically can be differentiated Conversely,...
A number of species Gram-negative bacteria can use insoluble minerals Fe(III) and Mn(IV) as extracellular respiratory electron acceptors. In some Shewanella, deca-heme transfer proteins lie at the face outer membrane (OM), where they interact with substrates. To reduce substrates, these redox must be charged by inner membrane/periplasmic system. Here, we present a spectro-potentiometric characterization trans-OM icosa-heme complex, MtrCAB, demonstrate its capacity to move electrons across...
Modern approaches for bioremediation of radionuclide contaminated environments are based on the ability microorganisms to effectively catalyze changes in oxidation states metals that turn influence their solubility. Although microbial metal reduction has been identified as an effective means immobilizing highly-soluble uranium(VI) complexes situ, biomolecular mechanisms U(VI) not well understood. Here, we show c-type cytochromes a dissimilatory metal-reducing bacterium, Shewanella oneidensis...
Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that located on the cell surface at termini trans-outer-membrane transfer conduits. The can potentially play multiple roles in mediating directly insoluble sinks, catalyzing exchange with flavin shuttles or participating intercytochrome along “nanowire” appendages. We present a 3.2-Å crystal structure one...
Summary The composition of extracellular polymeric substances (EPS) from Shewanella sp. HRCR‐1 biofilms was investigated using infrared spectroscopy and proteomics to provide insight into potential ecophysiological functions redox activity the EPS. Both bound loosely associated EPS were extracted prepared a hollow‐fibre membrane biofilm reactor. Fourier transform spectra revealed presence proteins, polysaccharides, nucleic acids, lipids fatty acids in fractions. Using global proteomic...
The mineral-respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes, MtrC and MtrA, brought together inside transmembrane porin, MtrB, to transport electrons across the outer membrane variety mineral-based electron acceptors. A proteoliposome system containing pool internalized carriers was used investigate how topology MtrCAB complex relates its ability lipid bilayer externally located Fe(III) oxides. With MtrA facing interior exposed...
ABSTRACT Shewanella oneidensis MR-1 is a facultatively anaerobic bacterium capable of using soluble and insoluble forms manganese [Mn(III/IV)] iron [Fe(III)] as terminal electron acceptors during respiration. To assess the structural association two outer membrane-associated c -type decaheme cytochromes (i.e., OmcA [SO1779] MtrC [SO1778]) their ability to reduce Fe(III)-nitrilotriacetic acid (NTA), we expressed these proteins with C-terminal tag in wild-type S. mutant deficient genes Δ omcA...
ABSTRACT Microbe-mineral and -metal interactions represent a major intersection between the biosphere geosphere but require high-resolution imaging analytical tools for investigation of microscale associations. Electron microscopy has been used extensively geomicrobial investigations, although bona fide , traditional methods sample preparation do not preserve native morphology microbiological components, especially extracellular polymers. Herein, we present direct comparative analysis...
The goal of this study was to quantify the contribution extracellular polymeric substances (EPS) U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison using cells with bound EPS (bEPS) and minimal EPS, we show that (i) bEPS from HRCR-1 biofilms contribute significantly immobilization, especially at low initial concentrations, through both sorption reduction; (ii) can be considered a functional extension for they likely play more important roles lower concentrations; (iii)...
ABSTRACT MtrC and OmcA are cell surface-exposed lipoproteins important for reducing solid metal oxides. Deletions of type II secretion system (T2SS) genes reduced their extracellular release accessibility to the proteinase K treatment, demonstrating direct involvement T2SS in translocation bacterial surface.
Abstract The ability of the metal reducer Shewanella oneidensis MR‐1 to generate electricity in microbial fuel cells (MFCs) depends on activity a predicted type IV prepilin peptidase; PilD. Analysis an S. pilD mutant indicated that it was deficient pili production (Msh and IV) II secretion (T2S). requirement for T2S reduction has been previously identified, but role remains largely unexplored. To define or Msh electron transfer, mutants lack one both pilus biogenesis systems were generated...
ABSTRACT Because of their cell surface locations, the outer membrane c -type cytochromes MtrC and OmcA Shewanella oneidensis MR-1 have been suggested to be terminal reductases for a range redox-reactive metals that form poorly soluble solids or do not readily cross membrane. In this work, we determined kinetics reduction series Fe(III) complexes with citrate, nitrilotriacetic acid (NTA), EDTA by using stopped-flow technique in combination theoretical computation methods. Stopped-flow kinetic...
Abstract In an effort to improve the understanding of electron transfer mechanisms at microbe–mineral interface, Shewanella oneidensis MR‐1 mutants with in‐frame deletions outer‐membrane cytochromes (OMCs), MtrC and OmcA, were characterized for ability reduce ferrihydrite (FH) using a suite microscopic, spectroscopic, biochemical techniques. Analysis purified recombinant proteins demonstrated that both undergo rapid exchange FH in vitro displaying faster rates than OmcA. Immunomicroscopy...
Summary Pertechnetate, 99 Tc(VII)O 4 – , is a highly mobile radionuclide contaminant at US Department of Energy sites that can be enzymatically reduced by range anaerobic and facultatively microorganisms, including Shewanella oneidensis MR‐1, to poorly soluble Tc(IV)O 2(s) . In other reduction generally considered catalysed hydrogenase. Here, we provide evidence although the NiFe hydrogenase MR‐1 was involved in H 2 ‐driven [presumably through direct coupling oxidation Tc(VII) reduction],...
Summary Biodiversity is changing at unprecedented rates, and it increasingly important that these changes are quantified through monitoring programmes. Previous recommendations for developing or enhancing programmes focus either on the end goals, intended use of data, how goals achieved, example volunteer involvement in citizen science, but not both. These rarely prioritized. We used a collaborative approach, involving 52 experts biodiversity UK , to develop list attributes relevance any...
Outer membrane (OM) cytochromes OmcA (SO1779) and MtrC (SO1778) are the integral components of electron transfer used by Shewanella oneidensis for anaerobic respiration metal (hydr)oxides. Here OmcA-MtrC interaction was identified in vivo using a novel hydrophobic chemical cross-linker (MRN) combined with immunoprecipitation techniques. In addition, identification other OM proteins from cross-linked complexes allows first visualization network. Further experiments on omcA mtrC mutant cells...
The fate of pertechnetate ((99)Tc(VII)O(4)(-)) during bioreduction was investigated in the presence 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) comparison with TcO(4)(-) absence Fh. In Fh, Tc present primarily as a fine-grained Tc(IV)/Fe precipitate that distinct from Tc(IV)O(2)·nH(2)O solids produced by direct biological Tc(VII) reduction. Aqueous concentrations (<0.2 μm) bioreduced Fh suspensions (1.7 to 3.2 ×...
A novel microfluidic reactor for biofilm growth was constructed to enable<italic>in situ</italic>chemical imaging of hydrated biofilms using ToF-SIMS.
A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface), was employed in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials sequential layers resulted biofilm spatial mapping. Two-dimensional (2D) images were reconstructed to report first three-dimensional hydrated elucidating and heterogeneity. 2D image principal component analysis conducted among...
While the product of microbial uranium reduction is often reported to be "UO(2)", a comprehensive characterization including stoichiometry and unit cell determination available for only one Shewanella species. Here, we compare products batch uranyl by collection dissimilatory metal- sulfate-reducing bacteria genera Shewanella, Geobacter, Anaeromyxobacter, Desulfovibrio under similar laboratory conditions. Our results demonstrate that U(VI) bioreduction this assortment commonly studied,...
Anaeromyxobacter dehalogenans strain 2CP-C reduces U(VI) and Tc(VII) to U(IV)O(2(s)) (uraninite) Tc(IV)O(2(S)) respectively. Kinetic studies with resting cells revealed that or reduction rates using H(2) as electron donor exceeded those observed in acetate-amended incubations. The of by A. resulted extracellular accumulation approximately 5 nm uraninite nanoparticles association a lectin-binding polymeric substance (EPS). did not affect UO(2(S)) nanoparticle size EPS, but the utilization...
Summary Phenazine‐1‐carboxylic acid (PCA) is produced by rhizobacteria in dryland but not irrigated wheat fields of the Pacific Northwest, USA. PCA promotes biofilm development bacterial cultures and colonization rhizospheres. However, its impact upon has been demonstrated rhizosphere, where biofilms influence terrestrial carbon nitrogen cycles with ramifications for crop soil health. Furthermore, relationships between moisture rates biosynthesis degradation have established. In this study,...
The availability of whole genome sequences has enabled the application powerful tools for assaying global expression patterns in environmentally relevant bacteria such as Shewanella oneidensis MR-1. A large number genes prokaryote genomes, including MR-1, have been annotated hypothetical, indicating that no similar protein yet identified other organisms. Using high-sensitivity MS coupled with accurate mass and time (AMT) tag methodology, 1078 tryptic peptides were collectively detected MR-1...
ABSTRACT UndA HRCR-6 was identified from the metal-reducing bacterium Shewanella sp. strain HRCR-6. Both in vivo and vitro characterization results indicate that is an outer membrane endecaheme c -type cytochrome probably has a key functional role extracellular reduction of iron [Fe(III)] oxides uranium [U(VI)] by