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Yang L, Wu H, Zhao Y, Tan X, Wei Y, Guan Y, Huang G. Shewanella oneidensis MR-1 dissimilatory reduction of ferrihydrite to highly enhance mineral transformation and reactive oxygen species production in redox-fluctuating environments. CHEMOSPHERE 2024; 352:141364. [PMID: 38336034 DOI: 10.1016/j.chemosphere.2024.141364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
Diverse paths generated by reactive oxygen species (ROS) can mediate contaminant transformation and fate in the soil/aquatic environments. However, the pathways for ROS production upon the oxygenation of redox-active ferrous iron minerals are underappreciated. Ferrihydrite (Fh) can be reduced to produce Fe(II) by Shewanella oneidensis MR-1, a representative strain of dissimilatory iron-reducing bacteria (DIRB). The microbial reaction formed a spent Fh product named mr-Fh that contained Fe(II). Material properties of mr-Fh were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Magnetite could be observed in all mr-Fh samples produced over 1-day incubation, which might greatly favor the Fe(II) oxygenation process to produce hydroxyl radical (•OH). The maximum amount of dissolved Fe(II) can reach 1.1 mM derived from added 1 g/L Fh together with glucose as a carbon source, much higher than the 0.5 mM generated in the case of the Luria-Bertani carbon source. This may confirm that MR-1 can effectively reduce Fh and produce biogenetic Fe(II). Furthermore, the oxygenation of Fe(II) on the mr-Fh surface can produce abundant ROS, wherein the maximum cumulative •OH content is raised to about 120 μM within 48 h at pH 5, but it is decreased to about 100 μM at pH 7 for the case of MR-1/Fh system after a 7-day incubation. Thus, MR-1-mediated Fh reduction is a critical link to enhance ROS production, and the •OH species is among them the predominant form. XPS analysis proves that a conservable amount of Fe(II) species is subject to adsorption onto mr-Fh. Here, MR-1-mediated ROS production is highly dependent on the redox activity of the form Fe(II), which should be the counterpart presented as the adsorbed Fe(II) on surfaces. Hence, our study provides new insights into understanding the mechanisms that can significantly govern ROS generation in the redox-oscillation environment.
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Affiliation(s)
- Lu Yang
- School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Honghai Wu
- School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China.
| | - Yixuan Zhao
- School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Xinjie Tan
- School of Environment, South China Normal University, Guangzhou, 510006, China
| | - Yanfu Wei
- National Observation and Research Station of Coastal Ecological Environments in Macao, Macao Environmental Research Institute, Macau University of Science and Technology, Taipa, 999078, Macao, China
| | - Yufeng Guan
- School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China.
| | - Gouyong Huang
- School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, 510006, China
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Insights into the Biosynthesis of Nanoparticles by the Genus Shewanella. Appl Environ Microbiol 2021; 87:e0139021. [PMID: 34495739 DOI: 10.1128/aem.01390-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The exploitation of microorganisms for the fabrication of nanoparticles (NPs) has garnered considerable research interest globally. The microbiological transformation of metals and metal salts into respective NPs can be achieved under environmentally benign conditions, offering a more sustainable alternative to chemical synthesis methods. Species of the metal-reducing bacterial genus Shewanella are able to couple the oxidation of various electron donors, including lactate, pyruvate, and hydrogen, to the reduction of a wide range of metal species, resulting in biomineralization of a multitude of metal NPs. Single-metal-based NPs as well as composite materials with properties equivalent or even superior to physically and chemically produced NPs have been synthesized by a number of Shewanella species. A mechanistic understanding of electron transfer-mediated bioreduction of metals into respective NPs by Shewanella is crucial in maximizing NP yields and directing the synthesis to produce fine-tuned NPs with tailored properties. In addition, thorough investigations into the influence of process parameters controlling the biosynthesis is another focal point for optimizing the process of NP generation. Synthesis of metal-based NPs using Shewanella species offers a low-cost, eco-friendly alternative to current physiochemical methods. This article aims to shed light on the contribution of Shewanella as a model organism in the biosynthesis of a variety of NPs and critically reviews the current state of knowledge on factors controlling their synthesis, characterization, potential applications in different sectors, and future prospects.
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Gonzalez NM, Fitch A, Al-Bazi J. Development of a RP-HPLC method for determination of glucose in Shewanella oneidensis cultures utilizing 1-phenyl-3-methyl-5-pyrazolone derivatization. PLoS One 2020; 15:e0229990. [PMID: 32163461 PMCID: PMC7067395 DOI: 10.1371/journal.pone.0229990] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 02/18/2020] [Indexed: 12/24/2022] Open
Abstract
A method was developed and validated for low-level detection of glucose. The method involves quantitation of glucose though derivitization with 1-phenyl-3-methyl-5-pyrazolone (PMP) and HPLC-DAD analysis. The developed method was found to be accurate and robust achieving detection limits as low as 0.09 nM. The applicability of the method was tested against microbial samples with glucose acting as a carbon fuel source. The method was shown to be able to accurately discriminate and quantify PMP-glucose derivatives within Shewanella oneidensis MR-1 samples. The method proved capable at examining glucose usage during the early hours of microbial growth, with detectable usage occurring as early as two hours. S. oneidensis cultures were found to grow more effectively in the presence of oxygen which coincided with more efficient glucose usage. Glucose usage further increased in the presence of competing electron acceptors. The rate at which S. oneidensis reached exponential growth was affected by the presence of ferric iron under microaerobic conditions. Such samples reached exponential growth approximately two hours sooner than aerobic samples.
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Affiliation(s)
- Norberto M. Gonzalez
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States of America
- * E-mail:
| | - Alanah Fitch
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL, United States of America
| | - John Al-Bazi
- Department of Chemistry, Northeastern Illinois University, Chicago, IL, United States of America
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Munar MP, Takahashi H, Okamura Y. Discovery of a Novel Gene Conferring Tellurite Tolerance Through Tellurite Reduction to Escherichia coli Transformant in Marine Sediment Metagenomic Library. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2019; 21:762-772. [PMID: 31637558 DOI: 10.1007/s10126-019-09922-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Metagenomic library construction using a marine sediment-enrichment was employed in order to recover tellurium from tellurite, a tellurium oxyanion, dissolved in water and then functional screening was performed to discover a novel gene related to tellurite reduction. Transmission electron microscopy (TEM) revealed the formation of intracellular Te crystals in Escherichia coli cells transformed with a specific DNA fragment from the marine sediment metagenome. The metagenome fragment was composed of 691 bp and showed low homology to known proteins. Phylogenetic analysis suggested that the metagenome fragment was related to Pseudomonas stutzeri. Cloning and expression of an open reading frame (ORF) on the metagenome fragment validated the role of the fragment in conferring tellurite resistance and tellurite-reducing activity to E. coli host cells. E. coli transformant containing the ORF1 showed resistance to 1 mM Na2TeO3. The optimal tellurite-reducing activity of cells containing the ORF1 was recorded at 37 °C and pH 7.0.
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Affiliation(s)
- Madison Pascual Munar
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima, Japan
| | - Hirokazu Takahashi
- Unit of Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Yoshiko Okamura
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima, Japan.
- Unit of Biotechnology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.
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Downie HF, Standerwick JP, Burgess L, Natrajan LS, Lloyd JR. Imaging redox activity and Fe(II) at the microbe-mineral interface during Fe(III) reduction. Res Microbiol 2018; 169:582-589. [DOI: 10.1016/j.resmic.2018.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/23/2018] [Accepted: 05/31/2018] [Indexed: 10/14/2022]
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Identification of Different Putative Outer Membrane Electron Conduits Necessary for Fe(III) Citrate, Fe(III) Oxide, Mn(IV) Oxide, or Electrode Reduction by Geobacter sulfurreducens. J Bacteriol 2018; 200:JB.00347-18. [PMID: 30038047 PMCID: PMC6148476 DOI: 10.1128/jb.00347-18] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 07/17/2018] [Indexed: 12/14/2022] Open
Abstract
Gram-negative metal-reducing bacteria utilize electron conduits, chains of redox proteins spanning the outer membrane, to transfer electrons to the extracellular surface. Only one pathway for electron transfer across the outer membrane of Geobacter sulfurreducens has been linked to Fe(III) reduction. However, G. sulfurreducens is able to respire a wide array of extracellular substrates. Here we present the first combinatorial genetic analysis of five different electron conduits via creation of new markerless deletion strains and complementation vectors. Multiple conduit gene clusters appear to have overlapping roles, including two that have never been linked to metal reduction. Another recently described cluster (ExtABCD) was the only electron conduit essential during electrode reduction, a substrate of special importance to biotechnological applications of this organism. At least five gene clusters in the Geobacter sulfurreducens genome encode putative “electron conduits” implicated in electron transfer across the outer membrane, each containing a periplasmic multiheme c-type cytochrome, integral outer membrane anchor, and outer membrane redox lipoprotein(s). Markerless single-gene-cluster deletions and all possible multiple-deletion combinations were constructed and grown with soluble Fe(III) citrate, Fe(III) and Mn(IV) oxides, and graphite electrodes poised at +0.24 V and −0.1 V versus the standard hydrogen electrode (SHE). Different gene clusters were necessary for reduction of each electron acceptor. During metal oxide reduction, deletion of the previously described omcBC cluster caused defects, but deletion of additional components in an ΔomcBC background, such as extEFG, were needed to produce defects greater than 50% compared to findings with the wild type. Deletion of all five gene clusters abolished all metal reduction. During electrode reduction, only the ΔextABCD mutant had a severe growth defect at both redox potentials, while this mutation did not affect Fe(III) oxide, Mn(IV) oxide, or Fe(III) citrate reduction. Some mutants containing only one cluster were able to reduce particular terminal electron acceptors better than the wild type, suggesting routes for improvement by targeting specific electron transfer pathways. Transcriptomic comparisons between fumarate and electrode-based growth conditions showed all of these ext clusters to be constitutive, and transcriptional analysis of the triple-deletion strain containing only extABCD detected no significant changes in expression of genes encoding known redox proteins or pilus components. These genetic experiments reveal new outer membrane conduit complexes necessary for growth of G. sulfurreducens, depending on the available extracellular electron acceptor. IMPORTANCE Gram-negative metal-reducing bacteria utilize electron conduits, chains of redox proteins spanning the outer membrane, to transfer electrons to the extracellular surface. Only one pathway for electron transfer across the outer membrane of Geobacter sulfurreducens has been linked to Fe(III) reduction. However, G. sulfurreducens is able to respire a wide array of extracellular substrates. Here we present the first combinatorial genetic analysis of five different electron conduits via creation of new markerless deletion strains and complementation vectors. Multiple conduit gene clusters appear to have overlapping roles, including two that have never been linked to metal reduction. Another recently described cluster (ExtABCD) was the only electron conduit essential during electrode reduction, a substrate of special importance to biotechnological applications of this organism.
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Surface Chemical Characterisation of Pyrite Exposed to Acidithiobacillus ferrooxidans and Associated Extracellular Polymeric Substances. MINERALS 2018. [DOI: 10.3390/min8040132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Usman M, Byrne JM, Chaudhary A, Orsetti S, Hanna K, Ruby C, Kappler A, Haderlein SB. Magnetite and Green Rust: Synthesis, Properties, and Environmental Applications of Mixed-Valent Iron Minerals. Chem Rev 2018; 118:3251-3304. [PMID: 29465223 DOI: 10.1021/acs.chemrev.7b00224] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mixed-valent iron [Fe(II)-Fe(III)] minerals such as magnetite and green rust have received a significant amount of attention over recent decades, especially in the environmental sciences. These mineral phases are intrinsic and essential parts of biogeochemical cycling of metals and organic carbon and play an important role regarding the mobility, toxicity, and redox transformation of organic and inorganic pollutants. The formation pathways, mineral properties, and applications of magnetite and green rust are currently active areas of research in geochemistry, environmental mineralogy, geomicrobiology, material sciences, environmental engineering, and environmental remediation. These aspects ultimately dictate the reactivity of magnetite and green rust in the environment, which has important consequences for the application of these mineral phases, for example in remediation strategies. In this review we discuss the properties, occurrence, formation by biotic as well as abiotic pathways, characterization techniques, and environmental applications of magnetite and green rust in the environment. The aim is to present a detailed overview of the key aspects related to these mineral phases which can be used as an important resource for researchers working in a diverse range of fields dealing with mixed-valent iron minerals.
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Affiliation(s)
- M Usman
- Environmental Mineralogy, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany.,Institute of Soil and Environmental Sciences , University of Agriculture , Faisalabad 38040 , Pakistan
| | - J M Byrne
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany
| | - A Chaudhary
- Environmental Mineralogy, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany.,Department of Environmental Science and Engineering , Government College University Faisalabad 38000 , Pakistan
| | - S Orsetti
- Environmental Mineralogy, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany
| | - K Hanna
- Univ Rennes, École Nationale Supérieure de Chimie de Rennes , CNRS, ISCR - UMR6226 , F-35000 Rennes , France
| | - C Ruby
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement , UMR 7564 CNRS-Université de Lorraine , 54600 Villers-Lès-Nancy , France
| | - A Kappler
- Geomicrobiology, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany
| | - S B Haderlein
- Environmental Mineralogy, Center for Applied Geosciences , University of Tübingen , 72074 Tübingen , Germany
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Zacharoff LA, Morrone DJ, Bond DR. Geobacter sulfurreducens Extracellular Multiheme Cytochrome PgcA Facilitates Respiration to Fe(III) Oxides But Not Electrodes. Front Microbiol 2017; 8:2481. [PMID: 29312190 PMCID: PMC5732950 DOI: 10.3389/fmicb.2017.02481] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/29/2017] [Indexed: 11/13/2022] Open
Abstract
Extracellular cytochromes are hypothesized to facilitate the final steps of electron transfer between the outer membrane of the metal-reducing bacterium Geobacter sulfurreducens and solid-phase electron acceptors such as metal oxides and electrode surfaces during the course of respiration. The triheme c-type cytochrome PgcA exists in the extracellular space of G. sulfurreducens, and is one of many multiheme c-type cytochromes known to be loosely bound to the bacterial outer surface. Deletion of pgcA using a markerless method resulted in mutants unable to transfer electrons to Fe(III) and Mn(IV) oxides; yet the same mutants maintained the ability to respire to electrode surfaces and soluble Fe(III) citrate. When expressed and purified from Shewanella oneidensis, PgcA demonstrated a primarily alpha helical structure, three bound hemes, and was processed into a shorter 41 kDa form lacking the lipodomain. Purified PgcA bound Fe(III) oxides, but not magnetite, and when PgcA was added to cell suspensions of G. sulfurreducens, PgcA accelerated Fe(III) reduction similar to addition of FMN. Addition of soluble PgcA to ΔpgcA mutants also restored Fe(III) reduction. This report highlights a distinction between proteins involved in extracellular electron transfer to metal oxides and poised electrodes, and suggests a specific role for PgcA in facilitating electron transfer at mineral surfaces.
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Affiliation(s)
- Lori A Zacharoff
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Dana J Morrone
- St. Louis College of Pharmacy, St. Louis, MO, United States
| | - Daniel R Bond
- Department of Plant and Microbial Biology, University of Minnesota, Minneapolis, MN, United States.,BioTechnology Institute, University of Minnesota, Minneapolis, MN, United States
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Iron Biochemistry is Correlated with Amyloid Plaque Morphology in an Established Mouse Model of Alzheimer's Disease. Cell Chem Biol 2017; 24:1205-1215.e3. [PMID: 28890316 DOI: 10.1016/j.chembiol.2017.07.014] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 01/19/2017] [Accepted: 07/28/2017] [Indexed: 11/21/2022]
Abstract
A signature characteristic of Alzheimer's disease (AD) is aggregation of amyloid-beta (Aβ) fibrils in the brain. Nevertheless, the links between Aβ and AD pathology remain incompletely understood. It has been proposed that neurotoxicity arising from aggregation of the Aβ1-42 peptide can in part be explained by metal ion binding interactions. Using advanced X-ray microscopy techniques at sub-micron resolution, we investigated relationships between iron biochemistry and AD pathology in intact cortex from an established mouse model over-producing Aβ. We found a direct correlation of amyloid plaque morphology with iron, and evidence for the formation of an iron-amyloid complex. We also show that iron biomineral deposits in the cortical tissue contain the mineral magnetite, and provide evidence that Aβ-induced chemical reduction of iron could occur in vivo. Our observations point to the specific role of iron in amyloid deposition and AD pathology, and may impact development of iron-modifying therapeutics for AD.
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11
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Measuring spectroscopy and magnetism of extracted and intracellular magnetosomes using soft X-ray ptychography. Proc Natl Acad Sci U S A 2016; 113:E8219-E8227. [PMID: 27930297 DOI: 10.1073/pnas.1610260114] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Characterizing the chemistry and magnetism of magnetotactic bacteria (MTB) is an important aspect of understanding the biomineralization mechanism and function of the chains of magnetosomes (Fe3O4 nanoparticles) found in such species. Images and X-ray absorption spectra (XAS) of magnetosomes extracted from, and magnetosomes in, whole Magnetovibrio blakemorei strain MV-1 cells have been recorded using soft X-ray ptychography at the Fe 2p edge. A spatial resolution of 7 nm is demonstrated. Precursor-like and immature magnetosome phases in a whole MV-1 cell were visualized, and their Fe 2p spectra were measured. Based on these results, a model for the pathway of magnetosome biomineralization for MV-1 is proposed. Fe 2p X-ray magnetic circular dichroism (XMCD) spectra have been derived from ptychography image sequences recorded using left and right circular polarization. The shape of the XAS and XMCD signals in the ptychographic absorption spectra of both sample types is identical to the shape and signals measured with conventional bright-field scanning transmission X-ray microscope. A weaker and inverted XMCD signal was observed in the ptychographic phase spectra of the extracted magnetosomes. The XMCD ptychographic phase spectrum of the intracellular magnetosomes differed from the ptychographic phase spectrum of the extracted magnetosomes. These results demonstrate that spectro-ptychography offers a superior means of characterizing the chemical and magnetic properties of MTB at the individual magnetosome level.
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Kondratyeva LM, Golubeva EM, Litvinenko ZN. Microbiological factors of the formation of iron-containing minerals. CONTEMP PROBL ECOL+ 2016. [DOI: 10.1134/s1995425516030070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Burke IT, Mosselmans JFW, Shaw S, Peacock CL, Benning LG, Coker VS. Impact of the Diamond Light Source on research in Earth and environmental sciences: current work and future perspectives. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:20130151. [PMID: 25624516 PMCID: PMC4308981 DOI: 10.1098/rsta.2013.0151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Diamond Light Source Ltd celebrated its 10th anniversary as a company in December 2012 and has now accepted user experiments for over 5 years. This paper describes the current facilities available at Diamond and future developments that enhance its capacities with respect to the Earth and environmental sciences. A review of relevant research conducted at Diamond thus far is provided. This highlights how synchrotron-based studies have brought about important advances in our understanding of the fundamental parameters controlling highly complex mineral-fluid-microbe interface reactions in the natural environment. This new knowledge not only enhances our understanding of global biogeochemical processes, but also provides the opportunity for interventions to be designed for environmental remediation and beneficial use.
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Affiliation(s)
- Ian T Burke
- Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - J Frederick W Mosselmans
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Samuel Shaw
- School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
| | - Caroline L Peacock
- Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Liane G Benning
- Earth Surface Science Institute, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
| | - Victoria S Coker
- School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
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van der Laan G, Figueroa AI. X-ray magnetic circular dichroism—A versatile tool to study magnetism. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2014.03.018] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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15
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Obst M, Schmid G. 3D chemical mapping: application of scanning transmission (soft) X-ray microscopy (STXM) in combination with angle-scan tomography in bio-, geo-, and environmental sciences. Methods Mol Biol 2014; 1117:757-781. [PMID: 24357389 DOI: 10.1007/978-1-62703-776-1_34] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The identification of environmental processes and mechanisms often requires information on the organochemical and inorganic composition of specimens at high spatial resolution. X-ray spectroscopy (XAS) performed in the soft X-ray range (100-2,200 eV) provides chemical speciation information for elements that are of high biogeochemical relevance such as carbon, nitrogen, and oxygen but also includes transition metals such as iron, manganese, or nickel. Synchrotron-based scanning transmission X-ray microscopy (STXM) combines XAS with high resolution mapping on the 20-nm scale. This provides two-dimensional (2D) quantitative information about the distribution of chemical species such as organic macromolecules, metals, or mineral phases within environmental samples. Furthermore, the combination of STXM with angle-scan tomography allows for three-dimensional (3D) spectromicroscopic analysis of bio-, geo-, or environmental samples. For the acquisition of STXM tomography data, the sample is rotated around an axis perpendicular to the X-ray beam. Various sample preparation approaches such as stripes cut from TEM grids or the preparation of wet cells allow for preparing environmentally relevant specimens in a dry or in a fully hydrated state for 2D and 3D STXM measurements. In this chapter we give a short overview about the principles of STXM, its application to environmental sciences, different preparation techniques, and the analysis and 3D reconstruction of STXM tomography data.
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Affiliation(s)
- Martin Obst
- Center for Applied Geoscience, University of Tuebingen, Tuebingen, Germany
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van der Laan G. Recent Advances in Circular and Linear X-ray Magnetic Dichroism: Experiment and Theory. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/08940886.2013.850372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals. Proc Natl Acad Sci U S A 2013; 110:6346-51. [PMID: 23538304 DOI: 10.1073/pnas.1220074110] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mineral-respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes, MtrC and MtrA, brought together inside a transmembrane porin, MtrB, to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system containing a pool of internalized electron carriers was used to investigate how the topology of the MtrCAB complex relates to its ability to transport electrons across a lipid bilayer to externally located Fe(III) oxides. With MtrA facing the interior and MtrC exposed on the outer surface of the phospholipid bilayer, the established in vivo orientation, electron transfer from the interior electron carrier pool through MtrCAB to solid-phase Fe(III) oxides was demonstrated. The rates were 10(3) times higher than those reported for reduction of goethite, hematite, and lepidocrocite by S. oneidensis, and the order of the reaction rates was consistent with those observed in S. oneidensis cultures. In contrast, established rates for single turnover reactions between purified MtrC and Fe(III) oxides were 10(3) times lower. By providing a continuous flow of electrons, the proteoliposome experiments demonstrate that conduction through MtrCAB directly to Fe(III) oxides is sufficient to support in vivo, anaerobic, solid-phase iron respiration.
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X-ray Absorption Spectroscopy. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-08-098259-5.00006-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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