Electron acceptor dependence of electron shuttle secretion and extracellular electron transfer by Shewanella oneidensis MR-1

2013 ◽  
Vol 136 ◽  
pp. 711-714 ◽  
Author(s):  
Chao Wu ◽  
Yuan-Yuan Cheng ◽  
Bing-Bing Li ◽  
Wen-Wei Li ◽  
Dao-Bo Li ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Acceptor ◽  
Shewanella Oneidensis ◽  
Extracellular Electron Transfer ◽  
Electron Shuttle

Bacterial nanotubes and their role as bacterial nanowires in Pseudomonas aeruginosa biofilms

2020 ◽  
Author(s):  
luyan ma
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Electron Transfer ◽  
Shewanella Oneidensis ◽  
Transfer Mechanism ◽  
Extracellular Electron Transfer ◽  
Electron Shuttle ◽  
Electron Transfer Mechanism ◽  
Energy Devices ◽  
Type Iv ◽  
Bacterial Nanowires

<p>Microbial nanowires are nanofilaments that could offer an extracellular electron transfer (EET) pathway linking the bacterial respiratory chain to external surfaces, such as oxidized metals in the environment and engineered electrodes in renewable energy devices. Filaments proposed to function as nanowires have been reported in multiple bacteria, yet it remains largely unclear about the composition and electron transfer mechanism of bacterial nanowires. Pseudomonas aeruginosa is an environmental and electrochemically active bacterium. In this study, we found nanotube-like extracellular filaments in P. aeruginosa biofilms, which were bacterial membrane extensions similar to the nanowires reported in Shewanella oneidensis. Remarkably, conductive probe atomic force microscope showed measurable conductivity of these extracellular filaments, suggesting that they may function as nanowires in P. aeruginosa. Our results also indicated that the electron shuttle pyocyanin significantly affected the conductivity of P. aeruginosa nanowires, suggesting that the electron transfer mechanism of P. aeruginosa nanowires was different from S. oneidensis. Furthermore, factors that impact biofilm formation, such as flagella, type IV pili, and exopolysaccharides, were not essential for nanowires formation, while affect the formation and length of nanowires of P. aeruginosa. Taken together, this is the first report that investigated the role of electron shuttle on the conductivity of nanowires and factors that affected nanowires formation.</p>

scholarly journals Protective Role of tolC in Efflux of the Electron Shuttle Anthraquinone-2,6-Disulfonate

2002 ◽  
Vol 184 (6) ◽  
pp. 1806-1810 ◽  
Author(s):  
J. Bruce H. Shyu ◽  
Douglas P. Lies ◽  
Dianne K. Newman
Keyword(s):  
Electron Transfer ◽  
Microbial Respiration ◽  
Critical Concentration ◽  
Shewanella Oneidensis ◽  
Protective Role ◽  
Extracellular Electron Transfer ◽  
Electron Shuttle ◽  
Functional Relationships ◽  
Electron Shuttles

ABSTRACT Extracellular electron transfer can play an important role in microbial respiration on insoluble minerals. The humic acid analog anthraquinone-2,6-disulfonate (AQDS) is commonly used as an electron shuttle during studies of extracellular electron transfer. Here we provide genetic evidence that AQDS enters Shewanella oneidensis strain MR-1 and causes cell death if it accumulates past a critical concentration. A tolC homolog protects the cell from toxicity by mediating the efflux of AQDS. Electron transfer to AQDS appears to be independent of the tolC pathway, however, and requires the outer membrane protein encoded by mtrB. We suggest that there may be structural and functional relationships between quinone-containing electron shuttles and antibiotics.

scholarly journals Regulation of Gene Expression in Shewanella oneidensis MR-1 during Electron Acceptor Limitation and Bacterial Nanowire Formation

2016 ◽  
Vol 82 (17) ◽  
pp. 5428-5443 ◽  
Author(s):  
Sarah E. Barchinger ◽  
Sahand Pirbadian ◽  
Christine Sambles ◽  
Carol S. Baker ◽  
Kar Man Leung ◽  
...  
Keyword(s):  
Gene Expression ◽  
Electron Transfer ◽  
Outer Membrane ◽  
Electron Acceptor ◽  
Shewanella Oneidensis ◽  
Oxygen Limitation ◽  
Extracellular Electron Transfer ◽  
Transport Pathways ◽  
Content Type ◽  
Genes Encoding

ABSTRACTIn limiting oxygen as an electron acceptor, the dissimilatory metal-reducing bacteriumShewanella oneidensisMR-1 rapidly forms nanowires, extensions of its outer membrane containing the cytochromes MtrC and OmcA needed for extracellular electron transfer. RNA sequencing (RNA-Seq) analysis was employed to determine differential gene expression over time from triplicate chemostat cultures that were limited for oxygen. We identified 465 genes with decreased expression and 677 genes with increased expression. The coordinated increased expression of heme biosynthesis, cytochrome maturation, and transport pathways indicates thatS. oneidensisMR-1 increases cytochrome production, including the transcription of genes encoding MtrA, MtrC, and OmcA, and transports these decaheme cytochromes across the cytoplasmic membrane during electron acceptor limitation and nanowire formation. In contrast, the expression of themtrAandmtrChomologsmtrFandmtrDeither remains unaffected or decreases under these conditions. TheompWgene, encoding a small outer membrane porin, has 40-fold higher expression during oxygen limitation, and it is proposed that OmpW plays a role in cation transport to maintain electrical neutrality during electron transfer. The genes encoding the anaerobic respiration regulator cyclic AMP receptor protein (CRP) and the extracytoplasmic function sigma factor RpoE are among the transcription factor genes with increased expression. RpoE might function by signaling the initial response to oxygen limitation. Our results show that RpoE activates transcription from promoters upstream ofmtrCandomcA. The transcriptome and mutant analyses ofS. oneidensisMR-1 nanowire production are consistent with independent regulatory mechanisms for extending the outer membrane into tubular structures and for ensuring the electron transfer function of the nanowires.IMPORTANCEShewanella oneidensisMR-1 has the capacity to transfer electrons to its external surface using extensions of the outer membrane called bacterial nanowires. These bacterial nanowires link the cell's respiratory chain to external surfaces, including oxidized metals important in bioremediation, and explain whyS. oneidensiscan be utilized as a component of microbial fuel cells, a form of renewable energy. In this work, we use differential gene expression analysis to focus on which genes function to produce the nanowires and promote extracellular electron transfer during oxygen limitation. Among the genes that are expressed at high levels are those encoding cytochrome proteins necessary for electron transfer.Shewanellacoordinates the increased expression of regulators, metabolic pathways, and transport pathways to ensure that cytochromes efficiently transfer electrons along the nanowires.

Impact of Graphitic Structures in Pyrogenic Carbon on Microbial Reduction of Ferrihydrite

2021 ◽  
Author(s):  
wentao yu ◽  
baoliang chen
Keyword(s):  
Electron Transfer ◽  
Pyrolysis Temperature ◽  
Shewanella Oneidensis ◽  
Exchange Capacity ◽  
Microbial Reduction ◽  
Systematic Evaluation ◽  
Extracellular Electron Transfer ◽  
Pyrogenic Carbon ◽  
The Impact

<p>Pyrogenic carbon plays important roles in microbial reduction of ferrihydrite by shuttling electrons in the extracellular electron transfer (EET) processes. Despite its importance, a full assessment on the impact of graphitic structures in pyrogenic carbon on microbial reduction of ferrihydrite has not been conducted. This study is a systematic evaluation of microbial ferrihydrite reduction by Shewanella oneidensis MR-1 in the presence of pyrogenic carbon with various graphitization extents. The results showed that the rates and extents of microbial ferrihydrite reduction were significantly enhanced in the presence of pyrogenic carbon, and increased with increasing pyrolysis temperature. Combined spectroscopic and electrochemical analyses suggested that the rate of microbial ferrihydrite reduction were dependent on the electrical conductivity of pyrogenic carbon (i.e., graphitization extent), rather than the electron exchange capacity. The key role of graphitic structures in pyrogenic carbon in mediating EET was further evidenced by larger microbial electrolysis current with pyrogenic carbon prepared at higher pyrolysis temperatures. This study provides new insights into the electron transfer in the pyrogenic carbon-mediated microbial reduction of ferrihydrite.</p>

Identifying the potential extracellular electron transfer pathways from a c-type cytochrome network

2014 ◽  
Vol 10 (12) ◽  
pp. 3138-3146 ◽  
Author(s):  
De-Wu Ding ◽  
Jun Xu ◽  
Ling Li ◽  
Jian-Ming Xie ◽  
Xiao Sun
Keyword(s):  
Electron Transfer ◽  
Shewanella Oneidensis ◽  
Extracellular Electron Transfer ◽  
Genome Wide ◽  
A Genome ◽  
Electron Transfer Pathways

A genome-wide c-type cytochrome network was constructed to explore the extracellular electron transfer pathways in Shewanella oneidensis MR-1.

scholarly journals A Hybrid Extracellular Electron Transfer Pathway Enhances the Survival of Vibrio natriegens

2020 ◽  
Vol 86 (19) ◽  
Author(s):  
Bridget E. Conley ◽  
Matthew T. Weinstock ◽  
Daniel R. Bond ◽  
Jeffrey A. Gralnick
Keyword(s):  
Electron Transfer ◽  
Shewanella Oneidensis ◽  
Anaerobic Respiration ◽  
Basic Research ◽  
Extracellular Electron Transfer ◽  
Content Type ◽  
Electron Transfer Pathway ◽  
Sedimentary Environments ◽  
Genetic Potential ◽  
Iron And Manganese

ABSTRACT Vibrio natriegens is the fastest-growing microorganism discovered to date, making it a useful model for biotechnology and basic research. While it is recognized for its rapid aerobic metabolism, less is known about anaerobic adaptations in V. natriegens or how the organism survives when oxygen is limited. Here, we describe and characterize extracellular electron transfer (EET) in V. natriegens, a metabolism that requires movement of electrons across protective cellular barriers to reach the extracellular space. V. natriegens performs extracellular electron transfer under fermentative conditions with gluconate, glucosamine, and pyruvate. We characterized a pathway in V. natriegens that requires CymA, PdsA, and MtrCAB for Fe(III) citrate and Fe(III) oxide reduction, which represents a hybrid of strategies previously discovered in Shewanella and Aeromonas. Expression of these V. natriegens genes functionally complemented Shewanella oneidensis mutants. Phylogenetic analysis of the inner membrane quinol dehydrogenases CymA and NapC in gammaproteobacteria suggests that CymA from Shewanella diverged from Vibrionaceae CymA and NapC. Analysis of sequenced Vibrionaceae revealed that the genetic potential to perform EET is conserved in some members of the Harveyi and Vulnificus clades but is more variable in other clades. We provide evidence that EET enhances anaerobic survival of V. natriegens, which may be the primary physiological function for EET in Vibrionaceae. IMPORTANCE Bacteria from the genus Vibrio occupy a variety of marine and brackish niches with fluctuating nutrient and energy sources. When oxygen is limited, fermentation or alternative respiration pathways must be used to conserve energy. In sedimentary environments, insoluble oxide minerals (primarily iron and manganese) are able to serve as electron acceptors for anaerobic respiration by microorganisms capable of extracellular electron transfer, a metabolism that enables the use of these insoluble substrates. Here, we identify the mechanism for extracellular electron transfer in Vibrio natriegens, which uses a combination of strategies previously identified in Shewanella and Aeromonas. We show that extracellular electron transfer enhanced survival of V. natriegens under fermentative conditions, which may be a generalized strategy among Vibrio spp. predicted to have this metabolism.

scholarly journals Developing a population-state decision system for intelligently reprogramming extracellular electron transfer in Shewanella oneidensis

2020 ◽  
Vol 117 (37) ◽  
pp. 23001-23010 ◽  
Author(s):  
Feng-He Li ◽  
Qiang Tang ◽  
Yang-Yang Fan ◽  
Yang Li ◽  
Jie Li ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Bacterial Growth ◽  
Metabolic Flux ◽  
Expression System ◽  
Shewanella Oneidensis ◽  
Cellular Growth ◽  
Extracellular Electron Transfer ◽  
Regulation System ◽  
Growth State ◽  
Pollutant Reduction

The unique extracellular electron transfer (EET) ability has positioned electroactive bacteria (EAB) as a major class of cellular chassis for genetic engineering aimed at favorable environmental, energy, and geoscience applications. However, previous efforts to genetically enhance EET ability have often impaired the basal metabolism and cellular growth due to the competition for the limited cellular resource. Here, we design a quorum sensing-based population-state decision (PSD) system for intelligently reprogramming the EET regulation system, which allows the rebalanced allocation of the cellular resource upon the bacterial growth state. We demonstrate that the electron output from Shewanella oneidensis MR-1 could be greatly enhanced by the PSD system via shifting the dominant metabolic flux from initial bacterial growth to subsequent EET enhancement (i.e., after reaching a certain population-state threshold). The strain engineered with this system achieved up to 4.8-fold EET enhancement and exhibited a substantially improved pollutant reduction ability, increasing the reduction efficiencies of methyl orange and hexavalent chromium by 18.8- and 5.5-fold, respectively. Moreover, the PSD system outcompeted the constant expression system in managing EET enhancement, resulting in considerably enhanced electron output and pollutant bioreduction capability. The PSD system provides a powerful tool for intelligently managing extracellular electron transfer and may inspire the development of new-generation smart bioelectrical devices for various applications.

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