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immobilization of whole cells by chemical vapor deposition of silica.effective entrapment of whole bacterial cells onto solid-phase materials can significantly improve bioprocessing and other biotechnology applications. cell immobilization allows integration of biocatalysts in a manner that maintains long-term cell viability and typically enhances process output. a wide variety of functionalized materials have been explored for microbial cell immobilization, and specific advantages and limitations were identified. the method described here is a simple, versatile, ...201323934813
systematic screening of carbon-based anode materials for microbial fuel cells with shewanella oneidensis mr-1.we present a systematic screening of carbon-based anode materials for microbial fuel cells with shewanella oneidensis mr-1. under anoxic conditions nanoporous activated carbon cloth is a superior anode material in terms of current density normalized to the projected anode area and anode volume (24.0±0.3 μa cm(-2) and 482±7 μa cm(-3) at -0.2 vs. sce, respectively). the good performance can be attributed to the high specific surface area of the material, which is available for mediated electron tr ...201323954244
decolorization of textile azo dye and congo red by an isolated strain of the dissimilatory manganese-reducing bacterium shewanella xiamenensis bc01.shewanella xiamenensis bc01 (sxm) was isolated from sediment collected off xiamen, china and was identified based on the phylogenetic tree of 16s rrna sequences and the gyrb gene. this strain showed high activity in the decolorization of textile azo dyes, especially methyl orange, reactive red 198, and recalcitrant dye congo red, decolorizing at rates of 96.2, 93.0, and 87.5%, respectively. sxm had the best performance for the specific decolorization rate (sdr) of azo dyes compared to proteus ha ...201423974367
physicochemical characterization of uridine phosphorylase from shewanella oneidensis mr-1. 201723975397
unveiling the details of electron transfer in multicenter redox proteins.metalloproteins modulate the intrinsic properties of transition metals to achieve controlled catalysis, electron transfer, or structural stabilization. those performing electron transport, redox proteins, are a diverse class of proteins with central roles in numerous metabolic and signaling pathways, including respiration and photosynthesis. many redox proteins have applications in industry, especially biotechnology, making them the focus of intense research. redox proteins may contain one or mu ...201423984680
exploring the roles of dna methylation in the metal-reducing bacterium shewanella oneidensis mr-1.we performed whole-genome analyses of dna methylation in shewanella oneidensis mr-1 to examine its possible role in regulating gene expression and other cellular processes. single-molecule real-time (smrt) sequencing revealed extensive methylation of adenine (n6ma) throughout the genome. these methylated bases were located in five sequence motifs, including three novel targets for type i restriction/modification enzymes. the sequence motifs targeted by putative methyltranferases were determined ...201323995632
efficacy of a 3rd generation high-throughput sequencing platform for analyses of 16s rrna genes from environmental samples.longer sequences of the bacterial 16s rrna gene could provide greater phylogenetic and taxonomic resolutions and advance knowledge of population dynamics within complex natural communities. we assessed the accuracy of a pacific biosciences (pacbio) single molecule, real time (smrt) sequencing based on dna polymerization, a promising 3rd generation high-throughput technique, and compared this to the 2nd generation roche 454 pyrosequencing platform. amplicons of the 16s rrna gene from a known isol ...201323999276
generalized bacterial genome editing using mobile group ii introns and cre-lox.efficient bacterial genetic engineering approaches with broad-host applicability are rare. we combine two systems, mobile group ii introns ('targetrons') and cre/lox, which function efficiently in many different organisms, into a versatile platform we call getr (genome editing via targetrons and recombinases). the introns deliver lox sites to specific genomic loci, enabling genomic manipulations. efficiency is enhanced by adding flexibility to the rna hairpins formed by the lox sites. we use the ...201324002656
graphene oxide as nanogold carrier for ultrasensitive electrochemical immunoassay of shewanella oneidensis with silver enhancement strategy.the genus shewanella is ubiquitous in environment and has been extensively studied for their applications in bioremediation. a novel immunoassay for ultrasensitive detection of shewanella oneidensis was presented based on graphene oxide (go) as nanogold carrier with silver enhancement strategy. the enhanced sensitivity was achieved by employing conjugate-featuring gold nanoparticles (aunps) and antibodies (ab) assembled on bovine serum albumin (bsa)-modified go (ab/aunps/bsa/go). after a sandwic ...201424016538
self-biased solar-microbial device for sustainable hydrogen generation.here we demonstrate the feasibility of continuous, self-sustained hydrogen gas production based solely on solar light and biomass (wastewater) recycling, by coupling solar water splitting and microbial electrohydrogenesis in a photoelectrochemical cell-microbial fuel cell (pec-mfc) hybrid device. the pec device is composed of a tio2 nanowire-arrayed photoanode and a pt cathode. the mfc is an air cathode dual-chamber device, inoculated with either shewanella oneidensis mr-1 (batch-fed on artifici ...201324025029
bacterial-fungal interactions enhance power generation in microbial fuel cells and drive dye decolourisation by an ex situ and in situ electro-fenton process.in this work, the potential for sustainable energy production from wastes has been exploited using a combination fungus-bacterium in microbial fuel cell (mfc) and electro-fenton technology. the fungus trametes versicolor was grown with shewanella oneidensis so that the bacterium would use the networks of the fungus to transport the electrons to the anode. this system generated stable electricity that was enhanced when the electro-fenton reactions occurred in the cathode chamber. this configurati ...201324035817
analyzing the modification of the shewanella oneidensis mr-1 flagellar filament.the unsheathed flagellar filament of shewanella oneidensis mr-1 is composed of two highly homologous flagellins, flaa, and the major structural unit, flab. we identified a gene cluster, so_3261-so_3265 (now sfmabcde), that is required for the formation of a fully functional filament and for motility. the predicted function of the corresponding gene products strongly indicated a role in flagellin modification. accordingly, loss of sfmabcde results in a significant mass shift of both flaa and flab ...201324039942
unique organizational and functional features of the cytochrome c maturation system in shewanella oneidensis.shewanella are renowned for their ability to respire on a wide range of electron acceptors, which has been partially accredited to the presence of a large number of the c-type cytochromes. in the model species s. oneidensis mr-1, at least 41 genes encode c-type cytochromes that are predicted to be intact, thereby likely functional. previously, in-frame deletion mutants for 36 of these genes were obtained and characterized. in this study, first we completed the construction of an entire set of c- ...201324040415
metabolic profiling directly from the petri dish using nanospray desorption electrospray ionization imaging mass spectrometry.understanding molecular interaction pathways in complex biological systems constitutes a treasure trove of knowledge that might facilitate the specific, chemical manipulation of the countless microbiological systems that occur throughout our world. however, there is a lack of methodologies that allow the direct investigation of chemical gradients and interactions in living biological systems, in real time. here, we report the use of nanospray desorption electrospray ionization (nanodesi) imaging ...201324047514
high power density microbial fuel cell with flexible 3d graphene-nickel foam as anode.the structure and electrical conductivity of anode play a significant role in the power generation of microbial fuel cells (mfcs). in this study, we developed a three-dimensional (3d) reduced graphene oxide-nickel (denoted as rgo-ni) foam as an anode for mfc through controlled deposition of rgo sheets onto the nickel foam substrate. the loading amount of rgo sheets and electrode surface area can be controlled by the number of rgo loading cycles. 3d rgo-ni foam anode provides not only a large acc ...201324057049
electrode assemblies composed of redox cascades from microbial respiratory electron transfer chains.respiratory and photosynthetic electron transfer chains are dependent on vectorial electron transfer through a series of redox proteins. examples include electron transfer from napc to napab nitrate reductase in paracoccus denitrificans and from cyma to fcc3 (flavocytochrome c3) fumarate reductase in shewanella oneidensis mr-1. in the present article, we demonstrate that graphite electrodes can serve as surfaces for the stepwise adsorption of napc and napab, and the stepwise adsorption of cyma a ...201324059515
combined geochemical and electrochemical methodology to quantify corrosion of carbon steel by bacterial activity.the availability of respiratory substrates, such as h2 and fe(ii,iii) solid corrosion products within nuclear waste repository, will sustain the activities of hydrogen-oxidizing bacteria (hob) and iron-reducing bacteria (irb). this may have a direct effect on the rate of carbon steel corrosion. this study investigates the effects of shewanella oneidensis (an hob and irb model organism) on the corrosion rate by looking at carbon steel dissolution in the presence of h2 as the sole electron donor. ...201424064199
h₂-dependent azoreduction by shewanella oneidensis mr-1: involvement of secreted flavins and both [ni-fe] and [fe-fe] hydrogenases.in this paper, the hydrogen (h2)-dependent discoloration of azo dye amaranth by shewanella oneidensis mr-1 was investigated. experiments with hydrogenase-deficient strains demonstrated that periplasmic [ni-fe] hydrogenase (hyab) and periplasmic [fe-fe] hydrogenase (hyda) are both respiratory hydrogenases of dissimilatory azoreduction in s. oneidensis mr-1. these findings suggest that hyab and hyda can function as uptake hydrogenases that couple the oxidation of h2 to the reduction of amaranth to ...201424081321
changes in translational efficiency is a dominant regulatory mechanism in the environmental response of bacteria.to understand how cell physiological state affects mrna translation, we used shewanella oneidensis mr-1 grown under steady state conditions at either 20% or 8.5% o2. using a combination of quantitative proteomics and rna-seq, we generated high-confidence data on >1000 mrna and protein pairs. by using a steady state model, we found that differences in protein-mrna ratios were primarily due to differences in the translational efficiency of specific genes. when oxygen levels were lowered, 28% of th ...201324081429
description of a riboflavin biosynthetic gene variant prevalent in the phylum proteobacteria.riboflavin (vitamin b2) is the precursor of flavin mononucleotide and flavin adenine dinucleotide, which are cofactors essential for a host of intracellular redox reactions. microorganisms synthesize flavins de novo to fulfill nutritional requirements, but it is becoming increasingly clear that flavins play a wider role in cellular physiology than was previously appreciated. flavins mediate diverse processes beyond the cytoplasmic membrane, including iron acquisition, extracellular respiration, ...201324097946
"replica-extraction-transfer" nanostructure-initiator mass spectrometry imaging of acoustically printed bacteria.traditionally, microbes are studied under controlled laboratory conditions as isolates in planktonic culture. however, this is a vast extrapolation from their natural state; development of new techniques is required to decipher the largely unknown world of microbial chemical interactions in more realistic environments. the field of mass spectrometry imaging has made significant progress in localizing metabolites in and around bacterial colonies, primarily by using maldi and esi-based techniques ...201324111681
modeling biofilms with dual extracellular electron transfer mechanisms.electrochemically active biofilms have a unique form of respiration in which they utilize solid external materials as terminal electron acceptors for their metabolism. currently, two primary mechanisms have been identified for long-range extracellular electron transfer (eet): a diffusion- and a conduction-based mechanism. evidence in the literature suggests that some biofilms, particularly shewanella oneidensis, produce the requisite components for both mechanisms. in this study, a generic model ...201324113651
oxygen allows shewanella oneidensis mr-1 to overcome mediator washout in a continuously fed bioelectrochemical system.many bioelectrochemical systems (bess) harness the ability of electrode-active microbes to catalyze reactions between electrodes and chemicals, often to perform useful functions such as wastewater treatment, fuel production, and biosensing. a microbial fuel cell (mfc) is one type of bes, which generates electric power through microbial respiration with an anode as the electron acceptor, and typically with oxygen reduction at the cathode to provide the terminal electron acceptor. oxygen intrusion ...201424122485
quinone-mediated microbial synthesis of reduced graphene oxide with peroxidase-like activity.the effects of different quinones on graphene oxide (go) reduction by shewanella oneidensis mr-1 and the peroxidase activity of the resultant reduced graphene oxide (qrgo) were studied. the presence of 100 μm anthraquinone-2-sulfonate (aqs), anthraquinone-2,6-disulfonate and 5-hydroxy-1,4-naphthoquinone could lead to 1.6-2.8-fold increase in go reduction rate, whereas anthraquinone-2-carboxylate slowed down the reduction. the stimulating effects of aqs increased with the increase of its concentr ...201324140856
the impact of ionic mercury on antioxidant defenses in two mercury-sensitive anaerobic bacteria.while the toxicological effects of mercury (hg) are well studied in mammals, little is known about the mechanisms of toxicity to bacterial cells lacking an hg resistance (mer) operon. we determined that shewanella oneidensis mr-1 is more sensitive to ionic mercury [hg(ii)] under aerobic conditions than in fumarate reducing conditions, with minimum inhibitory concentrations of 0.25 and 2 μm respectively. this increased sensitivity in aerobic conditions is not due to increased import, as more hg i ...201324150569
identification of a molecular signature unique to metal-reducing gammaproteobacteria.functional genes required for microbial (dissimilatory) metal reduction display high sequence divergence, which limits their utility as molecular biomarkers for tracking the presence and activity of metal-reducing bacteria in natural and engineered systems. in the present study, homologs of the outer membrane beta-barrel protein mtrb of metal-reducing gammaproteobacteria were found to contain a unique n-terminal cxxc motif that was missing from mtrb homologs of nonmetal-reducing gammaproteobacte ...201424188569
protection from oxidative stress relies mainly on derepression of oxyr-dependent katb and dps in shewanella oneidensis.shewanella thrives in redox-stratified environments where accumulation of h2o2 becomes inevitable because of the chemical oxidation of reduced metals, sulfur species, or organic molecules. as a research model, the representative species shewanella oneidensis has been extensively studied for its response to various stresses. however, little progress has been made toward an understanding of the physiological and genetic responses of this bacterium to oxidative stress, which is critically relevant ...201424214945
phosphorylation-dependent derepression by the response regulator hnoc in the shewanella oneidensis nitric oxide signaling network.nitric oxide (no) is an important signaling molecule that regulates diverse physiological processes in all domains of life. in many gammaproteobacteria, no controls behavioral responses through a complex signaling network involving heme-nitric oxide/oxygen binding (h-nox) domains as selective no sensors. in shewanella oneidensis, h-nox-mediated no sensing increases biofilm formation, which is thought to serve as a protective mechanism against no cytotoxicity. the h-nox/no-responsive (hno) signal ...201324218564
biogenic tellurium nanorods as a novel antivirulence agent inhibiting pyoverdine production in pseudomonas aeruginosa.while antibiotic resistance in bacteria is rapidly increasing, the development of new antibiotics has decreased in recent years. antivirulence drugs disarming rather than killing pathogens have been proposed to alleviate the problem of resistance inherent to existing biocidal antibiotics. here, we report a nontoxic biogenic nanomaterial as a novel antivirulence agent to combat bacterial infections caused by pseudomonas aeruginosa. we synthesized, in an environmentally benign fashion, tellurium n ...201424222554
promotion of iron oxide reduction and extracellular electron transfer in shewanella oneidensis by dmso.the dissimilatory metal reducing bacterium shewanella oneidensis mr-1, known for its capacity of reducing iron and manganese oxides, has great environmental impacts. the iron oxides reducing process is affected by the coexistence of alternative electron acceptors in the environment, while investigation into it is limited so far. in this work, the impact of dimethyl sulphoxide (dmso), a ubiquitous chemical in marine environment, on the reduction of hydrous ferric oxide (hfo) by s. oneidensis mr-1 ...201324244312
effects of bio-au nanoparticles on electrochemical activity of shewanella oneidensis wild type and δomca/mtrc mutant.both shewanella oneidensis mr-1 wild type and its mutant δomca/mtrc are capable of transforming au(iii) into au nanoparticles (aunps). cyclic voltammetry reveals a decrease in redox current after the wild type is exposed to au(iii) but an increase in oxidation current for the mutant. the peak current of the wild type is much higher than that of the mutant before the exposure of au(iii), but lower than that of the mutant after the formation of aunps. this suggests that damage to the electron tran ...201324264440
molecular mechanisms of heme based sensors from sediment organisms capable of extracellular electron transfer.bioelectrochemical systems (bes) rely on the metabolism of sediment bacteria capable of forming electrogenic biofilms to generate electrical work. the environment across the thickness of the biofilm is variable and in order for the cells to maintain their viability they require molecular sensors that allow them to adapt their metabolism to their respective environment. the dcra sensor from desulfovibrio vulgaris and the gsu 0582 and 0935 sensor domains from geobacter sulfurreducens appear to fun ...201424268904
roles of unda and mtrc of shewanella putrefaciens w3-18-1 in iron reduction.the completion of genome sequencing in a number of shewanella species, which are most renowned for their metal reduction capacity, offers a basis for comparative studies. previous work in shewanella oneidensis mr-1 has indicated that some genes within a cluster (mtrbac-omca-mtrfed) were involved in iron reduction. to explore new features of iron reduction pathways, we experimentally analyzed shewanella putrefaciens w3-18-1 since its gene cluster is considerably different from that of mr-1 in tha ...201324274142
biomog: a computational framework for the de novo generation or modification of essential biomass components.the success of genome-scale metabolic modeling is contingent on a model's ability to accurately predict growth and metabolic behaviors. to date, little focus has been directed towards developing systematic methods of proposing, modifying and interrogating an organism's biomass requirements that are used in constraint-based models. to address this gap, the biomass modification and generation (biomog) framework was created and used to generate lists of biomass components de novo, as well as to mod ...201324339916
disruption of putrescine biosynthesis in shewanella oneidensis enhances biofilm cohesiveness and performance in cr(vi) immobilization.although biofilm-based bioprocesses have been increasingly used in various applications, the long-term robust and efficient biofilm performance remains one of the main bottlenecks. in this study, we demonstrated that biofilm cohesiveness and performance of shewanella oneidensis can be enhanced through disrupting putrescine biosynthesis. through random transposon mutagenesis library screening, one hyperadherent mutant strain, cp2-1-s1, exhibiting an enhanced capability in biofilm formation, was o ...201424362428
contributions of the [nife]- and [fefe]-hydrogenase to h2 production in shewanella oneidensis mr-1 as revealed by isotope ratio analysis of evolved h(2).shewanella oneidensis mr-1 encodes both a [nife]- and an [fefe]-hydrogenase. while the output of these proteins has been characterized in mutant strains expressing only one of the enzymes, the contribution of each to h2 synthesis in the wild-type organism is not clear. here, we use stable isotope analysis of h2 in the culture headspace, along with transcription data and measurements of the concentrations of gases in the headspace, to characterize h2 production in the wild-type strain. after most ...201424372594
metabolically engineered glucose-utilizing shewanella strains under anaerobic conditions.comparative genome analysis of shewanella strains predicted that the strains metabolize preferably two- and three-carbon carbohydrates as carbon/electron source because many shewanella genomes are deficient of the key enzymes in glycolysis (e.g., glucokinase). in addition, all shewanella genomes are known to have only one set of genes associated with the phosphotransferase system required to uptake sugars. to engineer shewanella strains that can utilize five- and six-carbon carbohydrates, we con ...201424384311
a stable synergistic microbial consortium for simultaneous azo dye removal and bioelectricity generation.microbial species coexist in natural or engineered settings, where they encounter extensive competition and cooperation. interactions occurring through metabolite exchange or direct contact might be important in establishment of functional biodegradation consortium. understanding these interactions can facilitate manipulation of selected communities and exploitation of their capacity for specific industrial applications. here, a simple dual-species consortium (pseudomonas putida and shewanella o ...201424434696
selenite reduction by shewanella oneidensis mr-1 is mediated by fumarate reductase in periplasm.in situ reduction of selenite to elemental selenium (se(0)), by microorganisms in sediments and soils is an important process and greatly affects the environmental distribution and the biological effects of selenium. however, the mechanism behind such a biological process remains unrevealed yet. here we use shewanella oneidensis mr-1, a widely-distributed dissimilatory metal-reducing bacterium with a powerful and diverse respiration capability, to evaluate the involvement of anaerobic respiratio ...201424435070
tolerance of anaerobic bacteria to chlorinated solvents.the aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (cahs), perchloroethene (pce), carbon tetrachloride (ct), chloroform (cf) and 1,2-dichloroethane (1,2-dca), on the growth of eight anaerobic bacteria: four fermentative species (escherichia coli, klebsiella sp., clostridium sp. and paenibacillus sp.) and four respiring species (pseudomonas aeruginosa, geobacter sulfurreducens, shewanella oneidensis and desulfovibrio vulgaris). effective concentrations ...201424441515
[research on the bioaccesibility of hgs by shewanella oneidensis mr-1].the biological dissolution and methylation of solid hgs by shewanella oneidensis mr-1 and influenced factors under laboratory conditions were studied. results showed that s. oneidensis mr-1 could grow well at the low concentration of na2s, but its growth was inhibited at the high concentration of na2s, which mainly happened in the prolonged lag phase. iron reducing bacteria s. oneidensis mr-1 could access the solid mercuric sulfide, and rapidly promote the biological dissolution and methylation ...201324455961
improving the efficiency of plasmid transformation in shewanella oneidensis mr-1 by removing clai restriction site.here we demonstrate that elimination of clai restriction site from the sequence of a plasmid dna increases the efficiency of transformation of shewanella oneidensis mr-1 significantly. to achieve reliable transformation of s. oneidensis mr-1 plasmids either lacking clai site or isolated from primary transformants of s. oneidensis should be used.201424462975
a biochemical approach to study the role of the terminal oxidases in aerobic respiration in shewanella oneidensis mr-1.the genome of the facultative anaerobic γ-proteobacterium shewanella oneidensis mr-1 encodes for three terminal oxidases: a bd-type quinol oxidase and two heme-copper oxidases, a a-type cytochrome c oxidase and a cbb 3-type oxidase. in this study, we used a biochemical approach and directly measured oxidase activities coupled to mass-spectrometry analysis to investigate the physiological role of the three terminal oxidases under aerobic and microaerobic conditions. our data revealed that the cbb ...201424466040
characterization of microbial current production as a function of microbe-electrode-interaction.microbe-electrode-interactions are keys for microbial fuel cell technology. nevertheless, standard measurement routines to analyze the interplay of microbial physiology and material characteristics have not been introduced yet. in this study, graphite anodes with varying surface properties were evaluated using pure cultures of shewanella oneidensis and geobacter sulfurreducens, as well as defined and undefined mixed cultures. the evaluation routine consisted of a galvanostatic period, a current ...201424566287
uranium reduction by shewanella oneidensis mr-1 as a function of nahco3 concentration: surface complexation control of reduction kinetics.it is crucial to determine the controls on the kinetics of u(vi) bioreduction in order to understand and model the fate and mobility of u in groundwater systems and also to enhance the effectiveness of u bioremediation strategies. in this study, we measured the rate of u(vi) reduction by shewanella oneidensis strain mr-1 as function of nahco3 concentration. the experiments demonstrate that increasing concentrations of nahco3 in the system lead to slower u(vi) reduction kinetics. the nahco3 conce ...201424576101
signatures for mass spectrometry data quality.ensuring data quality and proper instrument functionality is a prerequisite for scientific investigation. manual quality assurance is time-consuming and subjective. metrics for describing liquid chromatography mass spectrometry (lc-ms) data have been developed; however, the wide variety of lc-ms instruments and configurations precludes applying a simple cutoff. using 1150 manually classified quality control (qc) data sets, we trained logistic regression classification models to predict whether a ...201424611607
comparisons of shewanella strains based on genome annotations, modeling, and experiments.shewanella is a genus of facultatively anaerobic, gram-negative bacteria that have highly adaptable metabolism which allows them to thrive in diverse environments. this quality makes them an attractive bacterial target for research in bioremediation and microbial fuel cell applications. constraint-based modeling is a useful tool for helping researchers gain insights into the metabolic capabilities of these bacteria. however, shewanella oneidensis mr-1 is the only strain with a genome-scale metab ...201424621294
cell growth and protein expression of shewanella oneidensis in biofilms and hydrogel-entrapped cultures.the performance of biofilm-based bioprocesses is difficult to predict and control because of the intrinsic heterogeneous and dynamic properties of microbial biofilms. biofilm mimics, such as microbial cells entrapped in polymeric scaffolds that are permeable for nutrients, have been proposed to replace real biofilms to achieve long-term robust performance in engineering applications. however, the physiological differences between cells that are physically entrapped in a synthetic polymeric matri ...201424626808
the impact of enzyme orientation and electrode topology on the catalytic activity of adsorbed redox enzymes.it is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. however, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substra ...201324634538
functional expression of carassius auratus cytochrome p4501a in a novel shewanella oneidensis expression system and application for the degradation of benzo[a]pyrene.cytochrome p4501a (cyp1a) in fish has attracted an increasing interest because of its important roles in the metabolic activation of certain xenobiotics such as aromatic hydrocarbons. cyps are reported to be expressed in yeast, insect cells and escherichia coli, but are critical for high-level expression. besides, this study found that the purification of recombinant goldfish cyp1a would result in a loss of enzyme activity. because large quantities of functional cyp1a are required, it is necessa ...201424637371
highly active bidirectional electron transfer by a self-assembled electroactive reduced-graphene-oxide-hybridized biofilm.low extracellular electron transfer performance is often a bottleneck in developing high-performance bioelectrochemical systems. herein, we show that the self-assembly of graphene oxide and shewanella oneidensis mr-1 formed an electroactive, reduced-graphene-oxide-hybridized, three-dimensional macroporous biofilm, which enabled highly efficient bidirectional electron transfers between shewanella and electrodes owing to high biomass incorporation and enhanced direct contact-based extracellular el ...201424644059
shewanella oneidensis cytochrome c nitrite reductase (ccnir) does not disproportionate hydroxylamine to ammonia and nitrite, despite a strongly favorable driving force.cytochrome c nitrite reductase (ccnir) from shewanella oneidensis, which catalyzes the six-electron reduction of nitrite to ammonia in vivo, was shown to oxidize hydroxylamine in the presence of large quantities of this substrate, yielding nitrite as the sole free nitrogenous product. uv-visible stopped-flow and rapid-freeze-quench electron paramagnetic resonance data, along with product analysis, showed that the equilibrium between hydroxylamine and nitrite is fairly rapidly established in the ...201424645742
evidence for function overlapping of cyma and the cytochrome bc1 complex in the shewanella oneidensis nitrate and nitrite respiration.shewanella oneidensis is an important model organism for its versatility of anaerobic respiration. cyma, a cytoplasmic membrane-bound tetraheme c-type cytochrome, plays a central role in anaerobic respiration by transferring electrons from the quinone pool to a variety of terminal reductases. although loss of cyma results in defect in respiration of many electron acceptors (eas), a significant share of the capacity remains in general. in this study, we adopted a transposon random mutagenesis met ...201424650148
innovative statistical interpretation of shewanella oneidensis microbial fuel cells data.the last decade of research has made significant strides toward practical applications of microbial fuel cells (mfcs); however, design improvements and operational optimization cannot be realized without equally considering engineering designs and biological interfacial reactions. in this study, the main factors contributing to mfcs' overall performance and their influence on mfc reproducibility are discussed. two statistical approaches were used to create a map of mfc components and their expan ...201424691574
two residues predominantly dictate functional difference in motility between shewanella oneidensis flagellins flaa and flab.nearly half of flagellated microorganisms possess a multiple-flagellin system. although a functional filament can be formed from one of multiple flagellins alone in many bacteria, it is more common that one flagellin is the major constituent and others contribute. underlying mechanisms proposed for such scenarios cover flagellin regulation of various levels, including transcription, translation, post-translational modification, secretion, and filament assembly. in shewanella oneidensis, the flag ...201424733391
d-optcom: dynamic multi-level and multi-objective metabolic modeling of microbial communities.most microbial communities change with time in response to changes and/or perturbations in environmental conditions. temporal variations in interspecies metabolic interactions within these communities can significantly affect their structure and function. here, we introduce d-optcom, an extension of the optcom procedure, for the dynamic metabolic modeling of microbial communities. it enables capturing the temporal dynamics of biomass concentration of the community members and extracellular conce ...201424742179
the x-ray crystal structure of shewanella oneidensis omca reveals new insight at the microbe-mineral interface.the x-ray crystal structure of shewanella oneidensis omca, an extracellular decaheme cytochrome involved in mineral reduction, was solved to a resolution of 2.7 å. the four omca molecules in the asymmetric unit are arranged so the minimum distance between heme 5 on adjacent omca monomers is 9 å, indicative of a transient omca dimer capable of intermolecular electron transfer. a previously identified hematite binding motif was identified near heme 10, forming a hydroxylated surface that would bri ...201424747425
sulfur-mediated electron shuttling during bacterial iron reduction.microbial reduction of ferric iron [fe(iii)] is an important biogeochemical process in anoxic aquifers. depending on groundwater ph, dissimilatory metal-reducing bacteria can also respire alternative electron acceptors to survive, including elemental sulfur (s(0)). to understand the interplay of fe/s cycling under alkaline conditions, we combined thermodynamic geochemical modeling with bioreactor experiments using shewanella oneidensis mr-1. under these conditions, s. oneidensis can enzymaticall ...201424789972
facile method to stain the bacterial cell surface for super-resolution fluorescence microscopy.a method to fluorescently stain the surfaces of both gram-negative and gram-positive bacterial cells compatible with super-resolution fluorescence microscopy is presented. this method utilizes a commercially-available fluorescent probe to label primary amines at the surface of the cell. we demonstrate efficient staining of two bacterial strains, the gram-negative shewanella oneidensis mr-1 and the gram-positive bacillus subtilis 168. using structured illumination microscopy and stochastic optica ...201424816810
promotion and nucleation of carbonate precipitation during microbial iron reduction.iron-bearing early diagenetic carbonate cements are common in sedimentary rocks, where they are thought to be associated with microbial iron reduction. however, little is yet known about how local environments around actively iron-reducing cells affect carbonate mineral precipitation rates and compositions. precipitation experiments with the iron-reducing bacterium shewanella oneidensis mr-1 were conducted to examine the potential role of cells in promoting precipitation and to explore the possi ...201424862734
microbial nanowires for bioenergy applications.microbial nanowires are electrically conductive filaments that facilitate long-range extracellular electron transfer. the model for electron transport along shewanella oneidensis nanowires is electron hopping/tunneling between cytochromes adorning the filaments. geobacter sulfurreducens nanowires are comprised of pili that have metal-like conductivity attributed to overlapping pi-pi orbitals of aromatic amino acids. the nanowires of geobacter species have been implicated in direct interspecies e ...201424863901
photoenhanced electrochemical interaction between shewanella and a hematite nanowire photoanode.here we report the investigation of interplay between light, a hematite nanowire-arrayed photoelectrode, and shewanella oneidensis mr-1 in a solar-assisted microbial photoelectrochemical system (solar mps). whole cell electrochemistry and microbial fuel cell (mfc) characterization of shewanella oneidensis strain mr-1 showed that these cells cultured under (semi)anaerobic conditions expressed substantial c-type cytochrome outer membrane proteins, exhibited well-defined redox peaks, and generated ...201424875432
colorimetric detection of shewanella oneidensis based on immunomagnetic capture and bacterial intrinsic peroxidase activity.rapid detection and enumeration of target microorganisms is considered as a powerful tool for monitoring bioremediation process that typically involves cleaning up polluted environments with functional microbes. a novel colorimetric assay is presented based on immunomagnetic capture and bacterial intrinsic peroxidase activity for rapidly detecting shewanella oneidensis, an important model organism for environmental bioremediation because of its remarkably diverse respiratory abilities. analyte b ...201424898751
iron triggers λso prophage induction and release of extracellular dna in shewanella oneidensis mr-1 biofilms.prophages are ubiquitous elements within bacterial chromosomes and affect host physiology and ecology in multiple ways. we have previously demonstrated that phage-induced lysis is required for extracellular dna (edna) release and normal biofilm formation in shewanella oneidensis mr-1. here, we investigated the regulatory mechanisms of prophage λso spatiotemporal induction in biofilms. to this end, we used a functional fluorescence fusion to monitor λso activation in various mutant backgrounds an ...201424951794
possible dynamically gated conductance along heme wires in bacterial multiheme cytochromes.the staggered cross decaheme configuration of electron transfer cofactors in the outer-membrane cytochrome mtrf serves as a prototype for conformationally gated multiheme electron transport. derived from the bacterium shewanella oneidensis, the staggered cross configuration reveals intersecting c-type octaheme and tetraheme "wires" containing thermodynamic "hills" and "valleys" (proc. natl. acad. sci. u. s. a. 2014, 11, 611-616), suggesting that the protein structure may include a dynamical mech ...201424975678
conservation of transcription start sites within genes across a bacterial genus.transcription start sites (tsss) lying inside annotated genes, on the same or opposite strand, have been observed in diverse bacteria, but the function of these unexpected transcripts is unclear. here, we use the metal-reducing bacterium shewanella oneidensis mr-1 and its relatives to study the evolutionary conservation of unexpected tsss. using high-resolution tiling microarrays and 5'-end rna sequencing, we identified 2,531 tsss in s. oneidensis mr-1, of which 18% were located inside coding se ...201424987095
managing oxidative stresses in shewanella oneidensis: intertwined roles of the oxyr and ohrr regulons.shewanella oneidensis, renowned for its remarkable respiratory abilities, inhabit redox-stratified environments prone to reactive oxygen species (ros)formation. two major oxidative stress regulators,analogues of oxyr and ohrr, specifically respond to h(2)o(2) and organic peroxides (op), respectively, are encoded in the genome based on sequence comparison to well-studied models. presumably, these analogues provide protection from ros. an understanding of s. oneidensis oxyr has been established re ...201425009841
cell-secreted flavins bound to membrane cytochromes dictate electron transfer reactions to surfaces with diverse charge and ph.the variety of solid surfaces to and from which microbes can deliver electrons by extracellular electron transport (eet) processes via outer-membrane c-type cytochromes (om c-cyts) expands the importance of microbial respiration in natural environments and industrial applications. here, we demonstrate that the bifurcated eet pathway of om c-cyts sustains the diversity of the eet surface in shewanella oneidensis mr-1 via specific binding with cell-secreted flavin mononucleotide (fmn) and riboflav ...201425012073
exploring the molecular mechanisms of electron shuttling across the microbe/metal space.dissimilatory metal reducing organisms play key roles in the biogeochemical cycle of metals as well as in the durability of submerged and buried metallic structures. the molecular mechanisms that support electron transfer across the microbe-metal interface in these organisms remain poorly explored. it is known that outer membrane proteins, in particular multiheme cytochromes, are essential for this type of metabolism, being responsible for direct and indirect, via electron shuttles, interaction ...201425018753
electrochemical selection and characterization of a high current-generating shewanella oneidensis mutant with altered cell-surface morphology and biofilm-related gene expression.shewanella oneidensis mr-1 exhibits extracellular electron transfer (eet) activity that is influenced by various cellular components, including outer-membrane cytochromes, cell-surface polysaccharides (cps), and regulatory proteins. here, a random transposon-insertion mutant library of s. oneidensis mr-1 was screened after extended cultivation in electrochemical cells (ecs) with a working electrode poised at +0.2 v (vs. ag/agcl) to isolate mutants that adapted to electrode-respiring conditions a ...201425028134
predicting bacterial essential genes using only sequence composition information.essential genes are those genes that are needed by organisms at any time and under any conditions. it is very important for us to identify essential genes from bacterial genomes because of their vital role in synthetic biology and biomedical practices. in this paper, we developed a support vector machine (svm)-based method to predict essential genes of bacterial genomes using only compositional features. these features are all derived from the primary sequences, i.e., nucleotide sequences and pr ...201425036505
pressure effects on the chimeric 3-isopropylmalate dehydrogenases of the deep-sea piezophilic shewanella benthica and the atmospheric pressure-adapted shewanella oneidensis.the chimeric 3-isopropylmalate dehydrogenase enzymes were constructed from the deep-sea piezophilic shewanella benthica and the shallow water shewanella oneidensis genes. the properties of the enzymatic activities under pressure conditions indicated that the central region, which contained the active center and the dimer forming domains, was shown to be the most important region for pressure tolerance in the deep-sea enzyme.201425036836
an arsenic-specific biosensor with genetically engineered shewanella oneidensis in a bioelectrochemical system.genetically engineered microbial biosensors have yet to realize commercial success in environmental applications due, in part, to difficulties associated with transducing and transmitting traditional bioluminescent information. bioelectrochemical systems (bess) output a direct electric signal that can be incorporated into devices for remote environmental monitoring. here, we describe a bes-based biosensor with genetically encoded specificity for a toxic metal. by placing an essential component o ...201425038536
the bacterial antitoxin hipb establishes a ternary complex with operator dna and phosphorylated toxin hipa to regulate bacterial persistence.nearly all bacteria exhibit a type of phenotypic growth described as persistence that is thought to underlie antibiotic tolerance and recalcitrant chronic infections. the chromosomally encoded high-persistence (hip) toxin-antitoxin proteins hipaso and hipbso from shewanella oneidensis, a proteobacterium with unusual respiratory capacities, constitute a type ii toxin-antitoxin protein module. here we show that phosphorylated hipaso can engage in an unexpected ternary complex with hipbso and doubl ...201425056321
selectivity mechanism of a bacterial homolog of the human drug-peptide transporters pept1 and pept2.peptide transporters of the pept family have key roles in the transport of di- and tripeptides across membranes as well as in the absorption of orally administered drugs in the small intestine. we have determined structures of a pept transporter from shewanella oneidensis (pept(so2)) in complex with three different peptides. the peptides bind in a large cavity lined by residues that are highly conserved in human pept1 and pept2. the bound peptides adopt extended conformations with their n termin ...201425064511
effects of flrbc on flagellar biosynthesis of shewanella oneidensis.as a most conserved complex molecular machine made up of a large number of structural subunits, the flagellum is under tight regulation by hierarchical arrangements. although variations in polar flagellar systems are found, most of them are restricted to multiple-copy components, such as flagellins and stators. therefore, these features are regarded to be peripheral relative to the comprehensive conservation. in this study, however, we present evidence to show that the difference in highly conse ...201425074236
membrane permeabilization underlies the enhancement of extracellular bioactivity in shewanella oneidensis by a membrane-spanning conjugated oligoelectrolyte.a stilbene-based membrane spanning conjugated oligoelectrolyte 4,4'-bis(4'-n,n-bis(6"-(n,n,n-trimethyl ammonium) hexyl) amino)-styryl) stilbene tetraiodide (dssn+) has been reported to be able to interact with bacterial cells and enhance their bioelectricity generation in bioelectrochemical devices, although the mechanism remains elusive. the goal of this study was to elucidate the impacts of dssn+ on extracellular bioactivity and the underlying mechanism. specifically, extracellular ferrihydrit ...201425091046
synergistic microbial consortium for bioenergy generation from complex natural energy sources.microbial species have evolved diverse mechanisms for utilization of complex carbon sources. proper combination of targeted species can affect bioenergy production from natural waste products. here, we established a stable microbial consortium with escherichia coli and shewanella oneidensis in microbial fuel cells (mfcs) to produce bioenergy from an abundant natural energy source, in the form of the sarcocarp harvested from coconuts. this component is mostly discarded as waste. however, through ...201425097866
distinct roles of major peptidoglycan recycling enzymes in β-lactamase production in shewanella oneidensis.β-lactam antibiotics were the earliest discovered and are the most widely used group of antibiotics that work by inactivating penicillin-binding proteins to inhibit peptidoglycan biosynthesis. as one of the most efficient defense strategies, many bacteria produce β-lactam-degrading enzymes, β-lactamases, whose biochemical functions and regulation have been extensively studied. a signal transduction pathway for β-lactamase induction by β-lactam antibiotics, consisting of the major peptidoglycan r ...201425136029
shewanella oneidensis mr-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components.bacterial nanowires offer an extracellular electron transport (eet) pathway for linking the respiratory chain of bacteria to external surfaces, including oxidized metals in the environment and engineered electrodes in renewable energy devices. despite the global, environmental, and technological consequences of this biotic-abiotic interaction, the composition, physiological relevance, and electron transport mechanisms of bacterial nanowires remain unclear. we report, to our knowledge, the first ...201425143589
flavin redox bifurcation as a mechanism for controlling the direction of electron flow during extracellular electron transfer.the iron-reducing bacterium shewanella oneidensis mr-1 has a dual directional electronic conduit involving 40 heme redox centers in flavin-binding outer-membrane c-type cytochromes (om c-cyts). while the mechanism for electron export from the om c-cyts to an anode is well understood, how the redox centers in om c-cyts take electrons from a cathode has not been elucidated at the molecular level. electrochemical analysis of live cells during switching from anodic to cathodic conditions showed that ...201425156475
the conjugated oligoelectrolyte dssn+ enables exceptional coulombic efficiency via direct electron transfer for anode-respiring shewanella oneidensis mr-1-a mechanistic study.shewanella oneidensis mr-1 was cultivated on lactate with poised graphite electrode acceptors (e = +0.2 v vs. ag/agcl) in order to explore the basis for sustained increases in anodic current output following the addition of the lipid-intercalating conjugated oligoelectrolyte (coe), 4,4'-bis(4'-(n,n-bis(6''-(n,n,n-trimethylammonium)hexyl)amino)-styryl)stilbene tetraiodide (dssn+). microbial cultures, which were spiked with dssn+, exhibit a ∼2.2-fold increase in charge collected, a ∼3.1-fold incre ...201425171764
the impact of γ radiation on the bioavailability of fe(iii) minerals for microbial respiration.conservation of energy by fe(iii)-reducing species such as shewanella oneidensis could potentially control the redox potential of environments relevant to the geological disposal of radioactive waste and radionuclide contaminated land. such environments will be exposed to ionizing radiation so characterization of radiation alteration to the mineralogy and the resultant impact upon microbial respiration of iron is essential. radiation induced changes to the iron mineralogy may impact upon microbi ...201425195952
identifying the potential extracellular electron transfer pathways from a c-type cytochrome network.extracellular electron transfer (eet) is the key feature of some bacteria, such as geobacter sulfurreducens and shewanella oneidensis. via eet processes, these bacteria can grow on electrode surfaces and make current output of microbial fuel cells. c-type cytochromes can be used as carriers to transfer electrons, which play an important role in eet processes. typically, from the inner (cytoplasmic) membrane through the periplasm to the outer membrane, they could form eet pathways. recent studies ...201425227320
genome-scale metabolic network validation of shewanella oneidensis using transposon insertion frequency analysis.transposon mutagenesis, in combination with parallel sequencing, is becoming a powerful tool for en-masse mutant analysis. a probability generating function was used to explain observed minihimar transposon insertion patterns, and gene essentiality calls were made by transposon insertion frequency analysis (tifa). tifa incorporated the observed genome and sequence motif bias of the minihimar transposon. the gene essentiality calls were compared to: 1) previous genome-wide direct gene-essentialit ...201425233219
structural insights into the role of iron-histidine bond cleavage in nitric oxide-induced activation of h-nox gas sensor proteins.heme-nitric oxide/oxygen (h-nox) binding domains are a recently discovered family of heme-based gas sensor proteins that are conserved across eukaryotes and bacteria. nitric oxide (no) binding to the heme cofactor of h-nox proteins has been implicated as a regulatory mechanism for processes ranging from vasodilation in mammals to communal behavior in bacteria. a key molecular event during no-dependent activation of h-nox proteins is rupture of the heme-histidine bond and formation of a five-coor ...201425253889
surface display of rogfp for monitoring redox status of extracellular microenvironments in shewanella oneidensis biofilms.biofilms are the most ubiquitous and resilient form of microbial life on earth. one most important feature of a biofilm is the presence of a self-produced matrix, which creates highly heterogeneous and dynamic microenvironments within biofilms. redox status in biofilm microenvironments plays a critical role in biofilm development and function. however, there is a lack of non-intrusive tools to quantify extracellular redox status of microenvironments within a biofilm matrix. in this study, using ...201525255765
microbially driven fenton reaction for degradation of the widespread environmental contaminant 1,4-dioxane.the carcinogenic cyclic ether compound 1,4-dioxane is employed as a stabilizer of chlorinated industrial solvents and is a widespread environmental contaminant in surface water and groundwater. in the present study, a microbially driven fenton reaction was designed to autocatalytically generate hydroxyl (ho•) radicals that degrade 1,4-dioxane. in comparison to conventional (purely abiotic) fenton reactions, the microbially driven fenton reaction operated at circumneutral ph and did not the requi ...201425313646
evidence for the requirement of cydx in function but not assembly of the cytochrome bd oxidase in shewanella oneidensis.cytochrome bd oxidase, existing widely in bacteria, produces a proton motive force by the vectorial charge transfer of protons and more importantly, endows bacteria with a number of vitally important physiological functions, such as enhancing tolerance to various stresses. although extensively studied as a cyda-cydb two-subunit complex for decades, the complex in certain groups of bacteria is recently found to in fact consist of an additional subunit, which is functionally essential.201525316290
comparative proteomics reveal the impact of omca/mtrc deletion on shewanella oneidensis mr-1 in response to hexavalent chromium exposure.hexavalent chromium [cr(vi)] is a priority pollutant causing serious environmental issues. microbial reduction provides an alternative strategy for cr(vi) remediation. the dissimilatory metal-reducing bacterium, shewanella oneidensis mr-1, was employed to study cr(vi) reduction and toxicity in this work. to understand the effect of membrane cytochromes on cr(vi) response, a comparative protein profile analysis from s. oneidensis mr-1 wild type and its mutant of deleting omca and mtrc (△omca/mtrc ...201425341401
theoretical exploration of optimal metabolic flux distributions for extracellular electron transfer by shewanella oneidensis mr-1.shewanella oneidensis mr-1 is one of the model microorganisms used for extracellular electron transfer. in this study, to elucidate the capability and the relevant metabolic processes of s. oneidensis mr-1 involved in an electron transferring environment, we employed genome-scale modelling to model the necessary metabolic states and flux adjustments for electricity generation in the cytochrome c-based direct electron transfer (det) mode, the nadh-linked mediated electron transfer (met) mode and ...201425342966
reduced heme levels underlie the exponential growth defect of the shewanella oneidensis hfq mutant.the rna chaperone hfq fulfills important roles in small regulatory rna (srna) function in many bacteria. loss of hfq in the dissimilatory metal reducing bacterium shewanella oneidensis strain mr-1 results in slow exponential phase growth and a reduced terminal cell density at stationary phase. we have found that the exponential phase growth defect of the hfq mutant in lb is the result of reduced heme levels. both heme levels and exponential phase growth of the hfq mutant can be completely restor ...201425356668
[bion-m1. biological activities of microorganisms under the conditions of a 30-day space flight].it was stated that spaceflight factors (sff) affect the chromosomal dna interchange during streptomyces crossing. cross polarity and primary input of a parent chromosome fragment in recombinant generation imply a more lasting cells contact in microgravity and a broader horizontal transport of genetic material. sff had no effect on recombination frequency and mutation in a model of parental auxotrophic markers reversion to prototrophism. it was demonstrated that sff boosted the fc31 phage exit fr ...201425365877
seeing is believing: novel imaging techniques help clarify microbial nanowire structure and function.novel imaging approaches have recently helped to clarify the properties of 'microbial nanowires'. geobacter sulfurreducens pili are actual wires. they possess metallic-like conductivity, which can be attributed to overlapping pi-pi orbitals of key aromatic amino acids. electrostatic force microscopy recently confirmed charge propagation along the pili, in a manner similar to carbon nanotubes. the pili are essential for long-range electron transport to insoluble electron acceptors and interspecie ...201525384844
accumulation of amorphous cr(iii)-te(iv) nanoparticles on the surface of shewanella oneidensis mr-1 through reduction of cr(vi).industrial effluents constitute a major source of metal pollution of aquatic bodies. moreover, due to their environmental persistence, toxic metal pollution is of special concern. microbial reduction is considered a promising strategy for toxic metal removal among the several methods available for metal remediation. here, we describe the coremediation of toxic cr(vi) and te(iv) by the dissimilatory metal reducing bacterium-shewanella oneidensis mr-1. in the presence of both cr(vi) and te(iv), s. ...201425393562
shewanella oneidensis cytochrome c maturation component ccmi is essential for heme attachment at the non-canonical motif of nitrite reductase nrfa.shewanella oneidensis is renowned for its respiratory versatility, which is largely due to abundant c-type cytochromes. maturation of these proteins depends on a ccm system encoded by genes in an unusual chromosomal arrangement, but the detailed mechanism is not understood. in this study, we identify so0265 as ccmi, an apocytochrome c chaperone that is important and essential for maturation of c-type cytochromes with the canonical heme binding motif(s) (hbm; cx(2)ch) and nitrite reductase nrfa c ...201525402661
multi-haem cytochromes in shewanella oneidensis mr-1: structures, functions and opportunities.multi-haem cytochromes are employed by a range of microorganisms to transport electrons over distances of up to tens of nanometres. perhaps the most spectacular utilization of these proteins is in the reduction of extracellular solid substrates, including electrodes and insoluble mineral oxides of fe(iii) and mn(iii/iv), by species of shewanella and geobacter. however, multi-haem cytochromes are found in numerous and phylogenetically diverse prokaryotes where they participate in electron transfe ...201525411412
regulation of nitrite resistance of the cytochrome cbb3 oxidase by cytochrome c scya in shewanella oneidensis.cytochrome c proteins, as enzymes to exchange electrons with substrates or as pure electron carriers to shuttle electrons, play vital roles in bacterial respiration and photosynthesis. in shewanella oneidensis, a research model for the respiratory diversity, at least 42 c-type cytochromes are predicted to be encoded in the genome and are regarded to be the foundation of its highly branched electron transport pathways. however, only a small number of c-type cytochromes have been extensively studi ...201525417822
nitrogen doped carbon nanoparticles enhanced extracellular electron transfer for high-performance microbial fuel cells anode.nitrogen doped carbon nanoparticles (ndcn) were applied to modify the carbon cloth anodes of microbial fuel cells (mfcs) inoculated with shewanella oneidensis mr-1, one of the most well-studied exoelectrogens. experimental results demonstrated that the use of ndcn increased anodic absorption of flavins (i.e., the soluble electron mediator secreted by s. oneidensis mr-1), facilitating shuttle-mediated extracellular electron transfer. in addition, we also found that ndcn enabled enhanced contact-b ...201525439129
laboratory investigation of high pressure survival in shewanella oneidensis mr-1 into the gigapascal pressure range.the survival of shewanella oneidensis mr-1 at up to 1500 mpa was investigated by laboratory studies involving exposure to high pressure followed by evaluation of survivors as the number (n) of colony forming units (cfu) that could be cultured following recovery to ambient conditions. exposing the wild type (wt) bacteria to 250 mpa resulted in only a minor (0.7 log n units) drop in survival compared with the initial concentration of 10(8) cells/ml. raising the pressure to above 500 mpa caused a l ...201425452750
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