scholarly journals Competitive Reduction of Pertechnetate (99TcO4−) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II)

2011 ◽  
Vol 45 (3) ◽  
pp. 951-957 ◽  
Author(s):  
Andrew E. Plymale ◽  
James K. Fredrickson ◽  
John M. Zachara ◽  
Alice C. Dohnalkova ◽  
Steve M. Heald ◽  
...  
Keyword(s):  
Competitive Reduction ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

scholarly journals Complex Iron Uptake by the Putrebactin-Mediated and Feo Systems in Shewanella oneidensis

2018 ◽  
Vol 84 (20) ◽  
Author(s):  
Lulu Liu ◽  
Shisheng Li ◽  
Sijing Wang ◽  
Ziyang Dong ◽  
Haichun Gao
Keyword(s):  
Iron Uptake ◽  
Iron Homeostasis ◽  
Shewanella Oneidensis ◽  
Special Role ◽  
Uptake System ◽  
Biological Processes ◽  
Content Type ◽  
Iron Uptake System ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

ABSTRACT Shewanella oneidensis is an extensively studied bacterium capable of respiring minerals, including a variety of iron ores, as terminal electron acceptors (EAs). Although iron plays an essential and special role in iron respiration of S. oneidensis, little has been done to date to investigate the characteristics of iron transport in this bacterium. In this study, we found that all proteins encoded by the pub-putA-putB cluster for putrebactin (S. oneidensis native siderophore) synthesis (PubABC), recognition-transport of Fe3+-putrebactin across the outer membrane (PutA), and reduction of ferric putrebactin (PutB) are essential to putrebactin-mediated iron uptake. Although homologs of PutA are many, none can function as its replacement, but some are able to work with other bacterial siderophores. We then showed that Fe2+-specific Feo is the other primary iron uptake system, based on the synthetical lethal phenotype resulting from the loss of both iron uptake routes. The role of the Feo system in iron uptake appears to be more critical, as growth is significantly impaired by the absence of the system but not of putrebactin. Furthermore, we demonstrate that hydroxyl acids, especially α-types such as lactate, promote iron uptake in a Feo-dependent manner. Overall, our findings underscore the importance of the ferrous iron uptake system in metal-reducing bacteria, providing an insight into iron homeostasis by linking these two biological processes. IMPORTANCE S. oneidensis is among the first- and the best-studied metal-reducing bacteria, with great potential in bioremediation and biotechnology. However, many questions regarding mechanisms closely associated with those applications, such as iron homeostasis, including iron uptake, export, and regulation, remain to be addressed. Here we show that Feo is a primary player in iron uptake in addition to the siderophore-dependent route. The investigation also resolved a few puzzles regarding the unexpected phenotypes of the putA mutant and lactate-dependent iron uptake. By elucidating the physiological roles of these two important iron uptake systems, this work revealed the breadth of the impacts of iron uptake systems on the biological processes.

scholarly journals Application of a High-Density Oligonucleotide Microarray Approach To Study Bacterial Population Dynamics during Uranium Reduction and Reoxidation

2006 ◽  
Vol 72 (9) ◽  
pp. 6288-6298 ◽  
Author(s):  
Eoin L. Brodie ◽  
Todd Z. DeSantis ◽  
Dominique C. Joyner ◽  
Seung M. Baek ◽  
Joern T. Larsen ◽  
...  
Keyword(s):  
Microbial Community Composition ◽  
High Density ◽  
Rrna Gene ◽  
Bacterial Populations ◽  
Process Comparison ◽  
Reducing Conditions ◽  
Reducing Bacteria ◽  
Geothrix Fermentans ◽  
Metal Reducing Bacteria

ABSTRACT Reduction of soluble uranium U(VI) to less-soluble uranium U(IV) is a promising approach to minimize migration from contaminated aquifers. It is generally assumed that, under constant reducing conditions, U(IV) is stable and immobile; however, in a previous study, we documented reoxidation of U(IV) under continuous reducing conditions (Wan et al., Environ. Sci. Technol. 2005, 39:6162-6169). To determine if changes in microbial community composition were a factor in U(IV) reoxidation, we employed a high-density phylogenetic DNA microarray (16S microarray) containing 500,000 probes to monitor changes in bacterial populations during this remediation process. Comparison of the 16S microarray with clone libraries demonstrated successful detection and classification of most clone groups. Analysis of the most dynamic groups of 16S rRNA gene amplicons detected by the 16S microarray identified five clusters of bacterial subfamilies responding in a similar manner. This approach demonstrated that amplicons of known metal-reducing bacteria such as Geothrix fermentans (confirmed by quantitative PCR) and those within the Geobacteraceae were abundant during U(VI) reduction and did not decline during the U(IV) reoxidation phase. Significantly, it appears that the observed reoxidation of uranium under reducing conditions occurred despite elevated microbial activity and the consistent presence of metal-reducing bacteria. High-density phylogenetic microarrays constitute a powerful tool, enabling the detection and monitoring of a substantial portion of the microbial population in a routine, accurate, and reproducible manner.

Biological Reduction of Np(V) and Np(V) Citrate by Metal-Reducing Bacteria

2007 ◽  
Vol 41 (8) ◽  
pp. 2764-2769 ◽  
Author(s):  
Gary A. Icopini ◽  
Hakim Boukhalfa ◽  
Mary P. Neu
Keyword(s):  
Biological Reduction ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

scholarly journals Plutonium(V/VI) Reduction by the Metal-Reducing Bacteria Geobacter metallireducens GS-15 and Shewanella oneidensis MR-1

2009 ◽  
Vol 75 (11) ◽  
pp. 3641-3647 ◽  
Author(s):  
Gary A. Icopini ◽  
Joe G. Lack ◽  
Larry E. Hersman ◽  
Mary P. Neu ◽  
Hakim Boukhalfa
Keyword(s):  
Electron Acceptor ◽  
Shewanella Oneidensis ◽  
Cell Suspensions ◽  
Reduced Form ◽  
Stable Form ◽  
Experimental Conditions ◽  
Geobacter Metallireducens ◽  
Terminal Electron Acceptor ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

ABSTRACT We examined the ability of the metal-reducing bacteria Geobacter metallireducens GS-15 and Shewanella oneidensis MR-1 to reduce Pu(VI) and Pu(V). Cell suspensions of both bacteria reduced oxidized Pu [a mixture of Pu(VI) and Pu(V)] to Pu(IV). The rate of plutonium reduction was similar to the rate of U(VI) reduction obtained under similar conditions for each bacteria. The rates of Pu(VI) and U(VI) reduction by cell suspensions of S. oneidensis were slightly higher than the rates observed with G. metallireducens. The reduced form of Pu was characterized as aggregates of nanoparticulates of Pu(IV). Transmission electron microscopy images of the solids obtained from the cultures after the reduction of Pu(VI) and Pu(V) by S. oneidensis show that the Pu precipitates have a crystalline structure. The nanoparticulates of Pu(IV) were precipitated on the surface of or within the cell walls of the bacteria. The production of Pu(III) was not observed, which indicates that Pu(IV) was the stable form of reduced Pu under these experimental conditions. Experiments examining the ability of these bacteria to use Pu(VI) as a terminal electron acceptor for growth were inconclusive. A slight increase in cell density was observed for both G. metallireducens and S. oneidensis when Pu(VI) was provided as the sole electron acceptor; however, Pu(VI) concentrations decreased similarly in both the experimental and control cultures.

scholarly journals Complete Genome Sequence of the Electricity-Producing “Thermincola potens” Strain JR

2010 ◽  
Vol 192 (15) ◽  
pp. 4078-4079 ◽  
Author(s):  
Kathryne G. Byrne-Bailey ◽  
Kelly C. Wrighton ◽  
Ryan A. Melnyk ◽  
Peter Agbo ◽  
Terry C. Hazen ◽  
...  
Keyword(s):  
Cell Surface ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

ABSTRACT “Thermincola potens” strain JR is one of the first Gram-positive dissimilatory metal-reducing bacteria (DMRB) for which there is a complete genome sequence. Consistent with the physiology of this organism, preliminary annotation revealed an abundance of multiheme c-type cytochromes that are putatively associated with the periplasm and cell surface in a Gram-positive bacterium. Here we report the complete genome sequence of strain JR.

scholarly journals Change of Oxidation/Reduction Potential of Solution by Metal-Reducing Bacteria and Roles of Biosynthesized Mackinawite

2011 ◽  
Vol 24 (4) ◽  
pp. 279-287 ◽  
Author(s):  
Seung-Yeop Lee ◽  
Jong-Min Oh ◽  
Min-Hoon Baik ◽  
Yong-Jae Lee
Keyword(s):  
Reduction Potential ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

A new insight on the effects of iron oxides and dissimilated metal-reducing bacteria on CH4 emissions in constructed wetland matrix systems

2021 ◽  
Vol 320 ◽  
pp. 124296
Author(s):  
Shiyi Cheng ◽  
Congli Qin ◽  
Huijun Xie ◽  
Wenxing Wang ◽  
Zhen Hu ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Constructed Wetland ◽  
Ch4 Emissions ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

On conducting electron traffic across the periplasm

2012 ◽  
Vol 40 (6) ◽  
pp. 1178-1180 ◽  
Author(s):  
Jeffrey A. Gralnick
Keyword(s):  
Physical Properties ◽  
Outer Membrane ◽  
Cytoplasmic Membrane ◽  
Respiratory Pathway ◽  
Redox Proteins ◽  
The Core ◽  
Core Components ◽  
Reducing Bacteria ◽  
Metal Reducing Bacteria

Dissimilatory metal-reducing bacteria are able to conduct electrons from their cytoplasmic membrane across the periplasm and the outer membrane to redox proteins located on the surface of their cells. The Mtr respiratory pathway in Shewanella is the best-understood metal-reducing pathway to date. The core components of this pathway are well agreed upon, but are they sufficient? Could there be other components that we have yet to uncover? The present paper specifically considers the periplasm, its physical properties and organization. Two models are presented to explain how electrons could be conducted across this compartment in Shewanella.

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