Isolation of U(VI) reduction-deficient mutants of<i>Shewanella putrefaciens</i>

Wade, Roy; DiChristina, Thomas J.

doi:10.1111/j.1574-6968.2000.tb09005.x

Cited by 82 publications

(12 citation statements)

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“…Bacteria of the genus Shewanella are widely recognized and used in biogeochemical research as model bacteria for examining dissimilatory metal reduction., see e.g., Refs. [ 42 , 21 , 39 , 2 , 22 , 47 ]. S. putrefaciens is a versatile, facultatively aerobic, Gram-negative metal-reducing bacterium, capable of obtaining energy for growth using Fe(III), Mn(IV), U(VI), , , Cr(VI), Tc(VII) and fumarate, each as sole TEA.…”

Section: Methodsmentioning

confidence: 99%

“…[ 19 ] Diverse bacteria are capable of dissimilatory U(VI) reduction, in many cases obtaining energy for growth by coupling U(VI) reduction to the oxidation of organic carbon or H 2 . [ 20 , 21 ] Bacteria such as Shewanella putrefaciens ,[ 22 , 23 ] Geobacter metallireducens and G. sulfurreducens [ 24 - 26 ] are capable of employing U(VI) as sole terminal electron acceptor (TEA), coupled with use of organic carbon or H 2 as electron donor. Other bacterial groups capable of dissimilatory U(VI) reduction include Desulfovibrio [ 27 - 32 ] Pseudomonas , [ 23 , 33 ] Thermus , [ 34 ]and some halophilic Archaea,[ 35 ] although many bacteria are not apparently capable of growth using U(VI) as sole terminal electron acceptor.…”

Section: Introductionmentioning

confidence: 99%

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Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens

Haas

Northup

2004

Geochem Trans

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We have examined the effects of aqueous complexation on rates of dissimilatory reductive precipitation of uranium by Shewanella putrefaciens. Uranium͑VI͒ was supplied as sole terminal electron acceptor to Shewanella putrefaciens ͑strain 200R͒ in defined laboratory media under strictly anaerobic conditions. Media were amended with different multidentate organic acids, and experiments were performed at different U͑VI͒ and ligand concentrations. Organic acids used as complexing agents were oxalic, malonic, succinic, glutaric, adipic, pimelic, maleic, citric, and nitrilotriacetic acids, tiron, EDTA, and Aldrich humic acid. Reductive precipitation of U͑VI͒, resulting in removal of insoluble amorphous UO 2 from solution, was measured as a function of time by determination of total dissolved U. Reductive precipitation was measured, rather than net U͑VI͒ reduction to U͑IV͒, to assess overall U removal rates from solution, which may be used to gauge the influence of chelation on microbial U mineralization. Initial linear rates of U reductive precipitation were found to correlate with stability constants of 1:1 aqueous U͑VI͒:ligand and U͑IV͒:ligand complexes. In the presence of strongly complexing ligands ͑e.g., NTA, Tiron, EDTA͒, UO 2 precipitation did not occur. Our results are consistent with ligand-retarded precipitation of UO 2 , which is analogous to ligand-assisted solid phase dissolution but in reverse: ligand exchange with the U 4ϩ aquo cation acts as a rate-limiting reaction moderating coordination of water molecules with U 4ϩ , which is a necessary step in UO 2 precipitation. Ligand exchange kinetics governing dissociation rates of ligands from U͑VI͒-organic complexes may also influence overall UO 2 production rates, although the magnitude of this effect is unclear relative to the effects of U͑IV͒-organic complexation. Our results indicate that natural microbial-aqueous systems containing abundant organic matter can inhibit the formation of biogenic amorphous UO 2 .

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens

Haas

Northup

2004

Geochem Trans

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“…Only few known strains are able to anaerobically reduce uranium to sustain their growth such as Shewanella putrefaciens strain 200, S. oneidensis MR-1, G. metallireducens, and Desulfotomaculum reducens (Lovley et al, 1991;Tebo and Obraztsova, 1998). The reduction of U(VI) anaerobically was particularly deeply investigated in both Shewanella strains (Lovley et al, 1991;Wade and DiChristina, 2000;Marshall et al, 2006). To date, no uranium-specific reductase has been reported, but certain ctype cytochromes implicated in Fe(III) and Mn(IV) anaerobic respirations have been found to be involved in uranium reduction, such as MtrA, MtrB, MtrC, and OmcA (Beliaev and Saffarini, 1998;Beliaev et al, 2001;Marshall et al, 2006).…”

Section: Uranium Respirationmentioning

confidence: 99%

Diversifying Anaerobic Respiration Strategies to Compete in the Rhizosphere

Lecomte

Achouak

Abrouk

et al. 2018

Front. Environ. Sci.

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“…In D. vulgaris, tetraheme cytochrome c 3 together with a periplasmic hydrogenase, its electron donor, were shown to be responsible for the majority, but not all, of the uranium reductase activity, while the alternate uranium reductases have yet to be identified (21,25,26). In Shewanella putrefaciens strain 200, a link between U(VI) reduction and nitrite reduction was discovered in the form of a mutant that simultaneously lost the ability to use both compounds as sole electron acceptors for growth (27). A transcription profiling experiment in S. oneidensis MR-1 followed by loss-of-function mutant analysis identified several proteins that were required for full U(VI) reductase activity, including cytochromes MtrA, MtrC, and CymA, as well as the outer membrane protein MtrB and a protein involved in menaquinone biosynthesis (MenC) (6).…”

Section: Discussionmentioning

confidence: 99%

A Highly Expressed High-Molecular-Weight S-Layer Complex of Pelosinus sp. Strain UFO1 Binds Uranium

Thorgersen

Lancaster

Rajeev

et al. 2017

Appl Environ Microbiol

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Cell suspensions of Pelosinus sp. strain UFO1 were previously shown, using spectroscopic analysis, to sequester uranium as U(IV) complexed with carboxyl and phosphoryl group ligands on proteins. The goal of our present study was to characterize the proteins involved in uranium binding. Virtually all of the uranium in UFO1 cells was associated with a heterodimeric protein, which was termed the uranium-binding complex (UBC). The UBC was composed of two S-layer domain proteins encoded by UFO1_4202 and UFO1_4203. Samples of UBC purified from the membrane fraction contained 3.3 U atoms/heterodimer, but significant amounts of phosphate were not detected. The UBC had an estimated molecular mass by gel filtration chromatography of 15 MDa, and it was proposed to contain 150 heterodimers (UFO1_4203 and UFO1_4202) and about 500 uranium atoms. The UBC was also the dominant extracellular protein, but when purified from the growth medium, it contained only 0.3 U atoms/heterodimer. The two genes encoding the UBC were among the most highly expressed genes within the UFO1 genome, and their expressions were unchanged by the presence or absence of uranium. Therefore, the UBC appears to be constitutively expressed and is the first line of defense against uranium, including by secretion into the extracellular medium. Although S-layer proteins were previously shown to bind U(VI), here we showed that U(IV) binds to S-layer proteins, we identified the proteins involved, and we quantitated the amount of uranium bound.IMPORTANCE Widespread uranium contamination from industrial sources poses hazards to human health and to the environment. Herein, we identified a highly abundant uranium-binding complex (UBC) from Pelosinus sp. strain UFO1. The complex makes up the primary protein component of the S-layer of strain UFO1 and binds 3.3 atoms of U(IV) per heterodimer. While other bacteria have been shown to bind U(VI) on their S-layer, we demonstrate here an example of U(IV) bound by an S-layer complex. The UBC provides a potential tool for the microbiological sequestration of uranium for the cleaning of contaminated environments.KEYWORDS contamination, uranium sequestration, uranium-binding protein U ranium is highly toxic and is also a radionuclide with a long half-life (1). Uranium mining, milling, and other anthropogenic industrial activities have led to widespread environmental contamination with associated hazards to human health and to the environment (2). In the United States, the U.S. Department of Energy (DOE) oversees the monitoring and restoration of waste sites at 12 facilities contaminated with uranium (3). Uranium is present in oxic fresh water as highly soluble U(VI). At pH values lower than 5.0, U(VI) is predominantly found as the free uranyl ion (UO 2 2ϩ ), and between pH values of 5.0 and 7.5, U(VI) is predominantly complexed with carbonate. At pH values

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Isolation of U(VI) reduction-deficient mutants ofShewanella putrefaciens

Cited by 82 publications

References 34 publications

Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens

Effects of aqueous complexation on reductive precipitation of uranium by Shewanella putrefaciens

Diversifying Anaerobic Respiration Strategies to Compete in the Rhizosphere

A Highly Expressed High-Molecular-Weight S-Layer Complex of Pelosinus sp. Strain UFO1 Binds Uranium

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