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type ii toxin/antitoxin system pareso /copaso stabilizes prophage cp4so in shewanella oneidensis.toxin/antitoxin (ta) loci are commonly found in mobile genetic elements such as plasmids and prophages. however, the physiological functions of these ta loci in prophages and cross-regulation among these ta loci remain largely unexplored. here, we characterized a newly discovered type ii ta pair, pareso /copaso , in the cp4so prophage in shewanella oneidensis. we demonstrated that pareso /copaso plays a critical role in the maintenance of cp4so in host cells after its excision. the toxin pareso ...201829411516
deletion of lytic transglycosylases increases beta-lactam resistance in shewanella oneidensis.production of chromosome-encoded β-lactamases confers resistance to β-lactams in many gram-negative bacteria. some inducible β-lactamases, especially the class c β-lactamase ampc in enterobacteriaceae, share a common regulatory mechanism, the ampr-ampc paradigm. induction of ampc is intimately linked to peptidoglycan recycling, and the lysr-type transcriptional regulator ampr plays a central role in the process. however, our previous studies have demonstrated that the expression of class d β-lac ...201829403465
tracking of shewanella oneidensis mr-1 biofilm formation of a microbial electrochemical system via differential pulse voltammetry.in this study, the electrochemical properties of a shewanella oneidensis mr-1 biofilm were investigated using a mini-microbial electrochemical system. the performance of the biofilm was shown, using discharge test and cyclic voltammetry investigations, to improve over time. differential pulse voltammograms were also acquired to determine the type of extracellular electron transfer that took place and to characterize the structure of the microbial biofilm formed on the electrode of the electroche ...201829398289
survival of anaerobic fe2+ stress requires the clpxp protease.shewanella oneidensis strain mr-1 is a versatile bacterium capable of respiring extracellular, insoluble ferric oxide minerals under anaerobic conditions. the respiration of iron minerals results in the production of soluble ferrous ions, which at high concentrations are toxic to living organisms. it is not fully understood how fe2+ is toxic to cells anaerobically; nor is it fully understood how s. oneidensis is able to resist high levels of fe2+ here we describe the results of a transposon-muta ...201829378887
defining the binding determinants of shewanella oneidensis oxyr: implications for the link between the contracted oxyr regulon and adaptation.it is well established that oxyr functions as a transcriptional activator of the peroxide stress response in bacteria, primarily based on studies on escherichia coli. recent investigations have revealed that oxyrs of some other bacteria can regulate gene expression through both repression and activation or repression only; however, the underlying mechanisms remain largely unknown. here, we demonstrated in g-proteobacterium shewanella oneidensis that regulation of oxyr on expression of major cata ...201829367341
ratiometric gas reporting: a non-disruptive approach to monitor gene expression in soils.fluorescent proteins are ubiquitous tools that are used to monitor the dynamic functions of natural and synthetic genetic circuits. however, these visual reporters can only be used in transparent settings, a limitation that complicates non-disruptive measurements of gene expression within many matrices, such as soils and sediments. we describe a new ratiometric gas reporting method for non-disruptively monitoring gene expression within hard-to-image environmental matrices. with this approach, c2 ...201829366321
biosynthesis and characterization of copper nanoparticles using shewanella oneidensis: application for click chemistry.copper nanoparticles (cu-nps) have a wide range of applications as heterogeneous catalysts. in this study, a novel green biosynthesis route for producing cu-nps using the metal-reducing bacterium, shewanella oneidensis is demonstrated. thin section transmission electron microscopy shows that the cu-nps are predominantly intracellular and present in a typical size range of 20-40 nm. serial block-face scanning electron microscopy demonstrates the cu-nps are well-dispersed across the 3d structure o ...201829359400
partially reciprocal replacement of flra and flrc in regulation of shewanella oneidensis flagellar biosynthesis.in some bacteria with a polar flagellum, an established regulatory hierarchy controlling step-wise assembly of the organelle consists of four regulators, flra, σ54, flrbc, and σ28 because all of these regulators mediate expression of multiple targets, they are essential to the assembly of a functional flagellum and therefore motility. however, this is not the case in γ-proteobacterium shewanella oneidensis: cells lacking flrb, flrc, or both remain flagellated and motile. here, we unravel the und ...201829358496
microbial nanowires - electron transport and the role of synthetic analogues.electron transfer is central to cellular life, from photosynthesis to respiration. in the case of anaerobic respiration, some microbes have extracellular appendages that can be utilised to transport electrons over great distances. two model organisms heavily studied in this arena are shewanella oneidensis and geobacter sulfurreducens. there is some debate over how, in particular, the geobacter sulfurreducens nanowires (formed from pilin nanofilaments) are capable of achieving the impressive feat ...201829357319
impedance spectroscopy of single bacterial nanofilament reveals water-mediated charge transfer.for decades respiratory chain and photosystems were the main firing field of the studies devoted to mechanisms of electron transfer in proteins. the concept of conjugated lateral electron and transverse proton transport during cellular respiration and photosynthesis, which was formulated in the beginning of 1960-s, has been confirmed by thousands of experiments. however, charge transfer in recently discovered bacterial nanofilaments produced by various electrogenic bacteria is regarded currently ...201829351332
network-based methods for identifying key active proteins in the extracellular electron transfer process in shewanella oneidensis mr-1.shewanella oneidensis mr-1 can transfer electrons from the intracellular environment to the extracellular space of the cells to reduce the extracellular insoluble electron acceptors (extracellular electron transfer, eet). benefiting from this eet capability, shewanella has been widely used in different areas, such as energy production, wastewater treatment, and bioremediation. genome-wide proteomics data was used to determine the active proteins involved in activating the eet process. we identif ...201829337910
linking spectral induced polarization (sip) and subsurface microbial processes: results from sand column incubation experiments.geophysical techniques, such as spectral induced polarization (sip), offer potentially powerful approaches for in situ monitoring of subsurface biogeochemistry. the successful implementation of these techniques as monitoring tools for reactive transport phenomena, however, requires the deconvolution of multiple contributions to measured signals. here, we present sip spectra and complementary biogeochemical data obtained in saturated columns packed with alternating layers of ferrihydrite-coated a ...201829336556
the mgte homolog fici acts as a secondary ferrous iron importer in shewanella oneidensis strain mr-1.the transport of metals into and out of cells is necessary for the maintenance of appropriate intracellular concentrations. metals are needed for incorporation into metalloproteins but become toxic at higher concentrations. many metal transport proteins have been discovered in bacteria, including the mg2+ transporter-e (mgte) family of passive mg2+/co2+ cation-selective channels. low sequence identity exists between members of the mgte family, indicating that substrate specificity may differ amo ...201829330185
geobacter sulfurreducens extracellular multiheme cytochrome pgca facilitates respiration to fe(iii) oxides but not electrodes.extracellular cytochromes are hypothesized to facilitate the final steps of electron transfer between the outer membrane of the metal-reducing bacterium geobacter sulfurreducens and solid-phase electron acceptors such as metal oxides and electrode surfaces during the course of respiration. the triheme c-type cytochrome pgca exists in the extracellular space of g. sulfurreducens, and is one of many multiheme c-type cytochromes known to be loosely bound to the bacterial outer surface. deletion of ...201729312190
biodegradation of sulfonamides by shewanella oneidensis mr-1 and shewanella sp. strain mr-4.because of extensive sulfonamides application in aquaculture and animal husbandry and the consequent increase in sulfonamides discharged into the environment, strategies to remediate sulfonamide-contaminated environments are essential. in this study, the resistance of shewanella oneidensis mr-1 and shewanella sp. strain mr-4 to the sulfonamides sulfapyridine (spy) and sulfamethoxazole (smx) were determined, and sulfonamides degradation by these strains was assessed. shewanella oneidensis mr-1 an ...201829302823
a simple method for assaying anaerobic biodegradation of dyes.anaerobic dye degradation is usually assayed using serum vials, which is time-consuming and costly. in this work, a simple method was established for real-time nondestructive assay of dye biodegradation using 96-well microtiter plates with petrolatum oil to avoid the volatilization and high transmittance transparent tape to prevent the permeation of oxygen. with the anaerobic degradation of methyl red and amaranth by shewanella oneidensis mr-1, this assay method was verified. further experiments ...201729277051
electron transfer strategies regulate carbonate mineral and micropore formation.some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. however, whether carbonates induced by microbial iron reduction have such features is unknown. iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). this diversity has the potential to create mineral biosign ...201829265883
the enhancement and inhibition of mercury reduction by natural organic matter in the presence of shewanella oneidensis mr-1.reduction-oxidation (redox) processes of mercury (hg) are of significant importance in influencing hg speciation, bioavailability, and fate in anoxic environments where natural organic matter (nom) and dissimilatory metal reducing bacteria (dmrb) are widely observed. however, the redox reaction between hg and nom, has not yet been studied in the presence of s. oneidensis mr-1 in anoxic environments. we have found that the reduction rate of mercuric mercury [hg(ii)] in the presence of elliott soi ...201829241125
cpda is involved in amino acid metabolism in shewanella oneidensis mr-1.cyclic 3',5'-adenosine monophosphate (camp) phosphodiesterase (cpd) is an enzyme that catalyzes the hydrolysis of camp, a signaling molecule affecting diverse cellular and metabolic processes in bacteria. some cpds are also known to function in camp-independent manners, while their physiological roles remain largely unknown. here, we investigated physiological roles of cpd in shewanella oneidensis mr-1, a model environmental bacterium, and report that cpd is involved in amino-acid metabolism. we ...201829235426
discovery of stimulator binding to a conserved pocket in the heme domain of soluble guanylyl cyclase.soluble guanylyl cyclase (sgc) is the receptor for nitric oxide and a highly sought-after therapeutic target for the management of cardiovascular diseases. new compounds that stimulate sgc show clinical promise, but where these stimulator compounds bind and how they function remains unknown. here, using a photolyzable diazirine derivative of a novel stimulator compound, iwp-051, and ms analysis, we localized drug binding to the β1 heme domain of sgc proteins from the hawkmoth manduca sexta and f ...201729222330
biofabrication of morphology improved cadmium sulfide nanoparticles using shewanella oneidensis bacterial cells and ionic liquid: for toxicity against brain cancer cell lines.the present work determines the anticancer activity of bio-mediated synthesized cadmium sulfide nanoparticles using the ionic liquid and bacterial cells (shewanella oneidensis). bacterial cells have been exposed to be important resources that hold huge potential as ecofriendly, cost-effective, evading toxic of dangerous chemicals and the alternative of conventional physiochemical synthesis. the shewanella oneidensis is an important kind of metal reducing bacterium, known as its special anaerobic ...201829207279
effect of shewanella oneidensis on the kinetics of fe(ii)-catalyzed transformation of ferrihydrite to crystalline iron oxides.iron (oxyhydr)oxides are widespread in natural and engineered systems, potent adsorbents of contaminants and a source of energy for iron-reducing bacteria. microbial reduction of iron (oxyhydr)oxides results in the formation of fe(ii) which can induce the transformation of these iron minerals, typically from less crystalline to more crystalline forms, affecting the biogeochemical cycling of iron and the behavior of any species adsorbed to the iron (oxyhydr)oxides. factors influencing the transfo ...201829205031
activating electrochemical catalytic activity of bio-palladium by hybridizing with carbon nanotube as "e- bridge".nano metal catalysts produced by bacteria has received increasing attention owing to its environmental friendly synthesis route. however, the formed metal nanoparticles are associated with poorly conductive cells and challenged to be electrochemically applied. in this study, palladium (pd) nanoparticles were synthesized by shewanella oneidensis mr-1. we demonstrated the limitation of palladized cells (pd-cells) serving as electro-catalysts can be relieved by hybridizing with the conductive carbo ...201729185498
a hierarchically modified graphite cathode with au nanoislands, cysteamine, and au nanocolloids for increased electricity-assisted production of isobutanol by engineered shewanella oneidensis mr-1.it is necessary to understand the surface structural effects of electrodes on the bioalcohol productivity of shewanella oneidensis mr-1, but this research area has not been deeply explored. here, we report that the electricity-assisted isobutanol productivity of shewanella oneidensis mr-1::pjl23 can be enhanced by sequentially modifying a graphite felt (gf) surface with au nanoislands (au), cysteamine (nh2), and au nanoparticles (au nps). after bacteria were incubated for 50 h with the unmodifie ...201729172431
chraso, the chromate efflux pump of shewanella oneidensis, improves chromate survival and reduction.the chromate efflux pump encoding gene chraso was identified on the chromosome of shewanella oneidensis mr1. although chraso is expressed without chromate, its expression level increases when cr(vi) is added. when deleted, the resulting mutant δchraso exhibits a chromate sensitive phenotype compared to that of the wild-type strain. interestingly, heterologous expression of chraso in e. coli confers resistance to high chromate concentration. moreover, expression of chraso in s. oneidensis and e. ...201729166414
observation of dielectric universalities in albumin, cytochrome c and shewanella oneidensis mr-1 extracellular matrix.the electrodynamics of metals is well understood within the drude conductivity model; properties of insulators and semiconductors are governed by a gap in the electronic states. but there is a great variety of disordered materials that do not fall in these categories and still respond to external field in an amazingly uniform manner. at radiofrequencies delocalized charges yield a frequency-independent conductivity σ 1(ν) whose magnitude exponentially decreases while cooling. with increasing fre ...201729147016
the prpf protein of shewanella oneidensis mr-1 catalyzes the isomerization of 2-methyl-cis-aconitate during the catabolism of propionate via the acnd-dependent 2-methylcitric acid cycle.the 2-methylcitric acid cycle (2-mcc) is a common route of propionate catabolism in microorganisms. in salmonella enterica, the prpbcde operon encodes most of the 2-mcc enzymes. in other organisms, e.g., shewanella oneidensis mr-1, two genes, acnd and prpf replace prpd, which encodes 2-methylcitrate dehydratase. we showed that together, s. oneidensis acnd and prpf (soacnd, soprpf) compensated for the absence of prpd in a s. enterica prpd strain. we also showed that soacnd had 2-methylcitrate deh ...201729145506
effect of anode polarization on biofilm formation and electron transfer in shewanella oneidensis/graphite felt microbial fuel cells.in microbial fuel cells, electricity generation is assumed by bacterial degradation of low-grade organics generating electrons that are transferred to an electrode. the nature and efficiency of the electron transfer from the bacteria to the electrodes are determined by several chemical, physical and biological parameters. specifically, the application of a specific potential at the bioanode has been shown to stimulate the formation of an electro-active biofilm, but the underlying mechanisms rema ...201729132011
enhanced bioreduction of nitrobenzene by reduced graphene oxide materials: effects of surface modification and coexisting soluble electron shuttles.reduced graphene oxide (rgo) can enhance the bioreduction of nitrobenzene by shewanella oneidensis mr-1. the effects of surface modification and coexisting soluble electron shuttles on rgo-enhanced bioreduction of nitrobenzene were investigated here. the results showed that rgo enhanced the secretion of extracellular polymeric substance and the bioreduction of nitrobenzene of several folds. no inhibition effect on nitrobenzene bioreduction was observed even when the concentration of rgo was as h ...201729105038
expansion of the active site of the azoreductase from shewanella oneidensis mr-1.azoreductase from shewanella oneidensis mr-1 (soazor) possesses great potential in cleaving azo bond of azo dyes during degradation progress. however, detailed information on interaction of soazor with either prosthetic group or substrate remains unavailable, mainly due to the absence of crystallization of soazor. in order to unravel these mechanisms, we firstly built the tertiary structure of soazor and then computationally predicted the binding mode of fmn, nadh and a model dye, methyl red (mr ...201729100166
synthetic klebsiella pneumoniae-shewanella oneidensis consortium enables glycerol-fed high-performance microbial fuel cells.microbial fuel cell (mfc) is an eco-friendly bio-electrochemical sys-tem that uses microorganism as biocatalyst to convert biomass into electricity. glycerol, as a waste in the biodiesel refinery processes, is an appealing substrate for mfc. nevertheless, glycerol cannot be utilized as carbon source by well-known exoelectrogens such as shewanella oneidensis. herein, to generate electricity by rapidly harnessing glycerol, the authors rationally constructed a klebsiella pneumoniae-shewanella oneid ...201729044893
effect of the anode potential on the physiology and proteome of shewanella oneidensis mr-1.shewanella species respire using iron and manganese oxides as well as electrodes as solid terminal electron acceptors. shewanella oneidenis mr-1 exploits mediated as well as direct extracellular electron transfer (eet) modes to transfer electrons at different formal potentials. these different eet modes at different potentials may utilise alternate electron transfer pathways. therefore, we investigated how different anode potentials, providing different maximum microbial energy gains impacted s. ...201829032328
degradation of the recalcitrant oil spill components anthracene and pyrene by a microbially driven fenton reaction.oil spill components include a range of toxic saturated, aromatic and polar hydrocarbons, including pyrene and anthracene. such contaminants harm natural ecosystems, adversely affect human health and negatively impact tourism and the fishing industries. current physical, chemical and biological remediation technologies are often unable to completely remove recalcitrant oil spill components, which accumulate at levels greater than regulatory limits set by the environmental protection agency. in t ...201729029043
regulation of nitric oxide signaling by formation of a distal receptor-ligand complex.the binding of nitric oxide (no) to the heme cofactor of heme-nitric oxide/oxygen binding (h-nox) proteins can lead to the dissociation of the heme-ligating histidine residue and yield a five-coordinate nitrosyl complex, an important step for no-dependent signaling. in the five-coordinate nitrosyl complex, no can reside on either the distal or proximal side of the heme, which could have a profound influence over the lifetime of the in vivo signal. to investigate this central molecular question, ...201728967923
bioelectrochemical biosensor for water toxicity detection: generation of dual signals for electrochemical assay confirmation.toxicity assessment of water is of great important to the safety of human health and to social security because of more and more toxic compounds that are spilled into the aquatic environment. therefore, the development of fast and reliable toxicity assessment methods is of great interest and attracts much attention. in this study, by using the electrochemical activity of shewanella oneidensis mr-1 cells as the toxicity indicator, 3,5-dichlorophenol (dcp) as the model toxic compound, a new biosen ...201828965160
decomposable quantum-dots/dna nanosphere for rapid and ultrasensitive detection of extracellular respiring bacteria.extracellular respiring bacteria (erb) are a group of bacteria capable of transferring electrons to extracellular acceptors and have important application in environmental remediation. in this study, a decomposable quantum-dots (qds)/dna nanosphere probe was developed for rapid and ultrasensitive detection of erb. the qds/dna nanosphere was self-assembled from qds-streptavidin conjugate (qds-sa) and y-shaped dna nanostructure that is constructed based on toehold-mediated strand displacement. it ...201828963964
investigation of a spontaneous mutant reveals novel features of iron uptake in shewanella oneidensis.shewanella oneidensis is among the first and the best studied bacteria capable of respiring minerals as terminal electron acceptors (eas), including a variety of iron ores. this respiration process relies on a large number of c-type cytochromes, which per se are iron-containing proteins. thus, iron plays an essential and special role in iron respiration of s. oneidensis, prompting extensive investigations into iron physiology. despite this, we still know surprisingly little about the components ...201728924168
in situ characterization of shewanella oneidensis mr1 biofilms by salvi and tof-sims.bacterial biofilms are surface-associated communities that are vastly studied to understand their self-produced extracellular polymeric substances (eps) and their roles in environmental microbiology. this study outlines a method to cultivate biofilm attachment to the system for analysis at the liquid vacuum interface (salvi) and achieve in situ chemical mapping of a living biofilm by time-of-flight secondary ion mass spectrometry (tof-sims). this is done through the culturing of bacteria both ou ...201728872139
structural dissection of shewanella oneidensis old yellow enzyme 4 bound to a meisenheimer complex and (nitro)phenolic ligands.shewanella oneidensis, a gram-negative γ-proteobacterium with an extensive redox capacity, possesses four old yellow enzyme (oye) homologs. of these, shewanella yellow enzyme 4 (sye4) is implicated in resistance to oxidative stress. here, we present a series of high-resolution crystal structures for sye4 in the oxidized and reduced states, and in complex with phenolic ligands and the nitro-aromatic explosive picric acid. the structures unmask new features, including the identification of a bindi ...201728869767
sensitive amperometric detection of riboflavin with a whole-cell electrochemical sensor.a novel whole-cell electrochemical sensor was developed and applied for sensitive amperometric detection of riboflavin. in this work, a whole-cell based riboflavin redox cycling system was characterized, in which electroactive bacteria shewanella oneidensis mr-1 was employed as the biocatalyst to regenerate the reduced riboflavin after the electrode oxidation. this redox cycling system efficiently enhanced the electrochemical response of riboflavin and enabled a stable current output at poised e ...201728864185
use of fourier transform infrared spectroscopy to examine the fe(ii)-catalyzed transformation of ferrihydrite.the fe(ii)-catalyzed transformation of the poorly crystalline fe(iii) oxyhydroxide mineral, ferrihydrite (fh), to more crystalline fe(iii) mineral species such as magnetite, goethite, and lepidocrocite has been quantitatively evaluated under various conditions using x-ray adsorption spectroscopy (xas) and fourier transform infrared (ftir) spectroscopy. using the peak height of signature ftir peaks of sub-micron sized lepidocrocite and goethite references minerals, the ftir results were comparabl ...201728841994
reduction pathway and mechanism of chloronitrobenzenes synergistically catalyzed by biopd and shewanella oneidensis mr-1 assisted by calculation.although microbial synthesized palladium nanoparticles (biopd) have been demonstrated to exhibit a great activity toward dechlorination of several chlorinated pollutants, there is no systematic investigation into the substituent effect on dechlorination. chloronitrobenzenes are widely used for manufacturing and known as persistent pollutants with recalcitrance of biodegradation for nitro groups. in this work, biopd was synthesized by shewanella oneidensis mr-1. the dechlorination of 2-chloronitr ...201728841432
directed biofabrication of nanoparticles through regulating extracellular electron transfer.biofabrication of nanomaterials is currently constrained by a low production efficiency and poor controllability on product quality compared to chemical synthetic routes. in this work, we show an attractive new biosynthesis system to break these limitations. a directed production of selenium-containing nanoparticles in shewanella oneidensis mr-1 cells, with fine-tuned composition and subcellular synthetic location, was achieved by modifying the extracellular electron transfer chain. by taking ad ...201728825808
natural organic matter concentration impacts the interaction of functionalized diamond nanoparticles with model and actual bacterial membranes.changes to nanoparticle surface charge, colloidal stability, and hydrodynamic properties induced by interaction with natural organic matter (nom) warrant consideration in assessing the potential for these materials to adversely impact organisms in the environment. here, we show that acquisition of a coating, or "corona", of nom alters the hydrodynamic and electrokinetic properties of diamond nanoparticles (dnps) functionalized with the polycation poly(allylamine hcl) in a manner that depends on ...201728817268
microfluidic dielectrophoresis device for trapping, counting and detecting shewanella oneidensis at the cell level.shewanella oneidensis, a model organism for electrochemical activity bacteria, has been widely studied at the biofilm level. however, to obtain more information regarding this species, it is essential to develop an approach to trap and detect s. oneidensis at the cell level. in this study, we report a rapid and label-free microfluidic platform for trapping, counting and detecting s. oneidensis cells. a microfluidic chip was integrated with a modified dielectrophoresis (dep) trapping technique an ...201828810232
the molecular basis for binding of an electron transfer protein to a metal oxide surface.achieving fast electron transfer between a material and protein is a long-standing challenge confronting applications in bioelectronics, bioelectrocatalysis, and optobioelectronics. interestingly, naturally occurring extracellular electron transfer proteins bind to and reduce metal oxides fast enough to enable cell growth, and thus could offer insight into solving this coupling problem. while structures of several extracellular electron transfer proteins are known, an understanding of how these ...201728806874
engineering shewanella oneidensis enables xylose-fed microbial fuel cell.the microbial fuel cell (mfc) is a green and sustainable technology for electricity energy harvest from biomass, in which exoelectrogens use metabolism and extracellular electron transfer pathways for the conversion of chemical energy into electricity. however, shewanella oneidensis mr-1, one of the most well-known exoelectrogens, could not use xylose (a key pentose derived from hydrolysis of lignocellulosic biomass) for cell growth and power generation, which limited greatly its practical appli ...201728804512
a rapid and simple protocol to prepare a living biocomposite that mimics electroactive biofilms.a living material was formed by self-assembly of bacterial cells (shewanella oneidensis mr-1 or pseudomonas fluorescens) with carbon nanotubes in the presence of cytochrome c from a bovine heart with the goal to mimic electroactive biofilms. the role of cytochrome c on self-assembly, cell viability and extracellular electron transfer was studied. scanning electron microscopy and dynamic light scattering experiments highlighted its role on the self-assembly of bacteria‑carbon nanotube aggregates ...201728802176
redox-active oxygen-containing functional groups in activated carbon facilitate microbial reduction of ferrihydrite.carbonaceous materials are commonly used in agronomic and environmental applications primarily as geosorbents, but their redox properties that may affect biogeochemical reactions are rarely documented. herein, the role of activated carbon (ac) mediating microbial reduction of ferrihydrite is studied. our batch experiment results show that ac facilitated the reduction of ferrihydrite by shewanella oneidensis mr-1, but the pretreatment of ac with hno3 further increased the rate of reduction. the r ...201728782366
protection of the general stress response σs factor by the crsr regulator allows a rapid and efficient adaptation of shewanella oneidensis.to cope with environmental stresses, bacteria have evolved various strategies, including the general stress response (gsr). gsr is governed by an alternative transcriptional σ factor named σs (rpos) that associates with rna polymerase and controls the expression of numerous genes. previously, we have reported that posttranslational regulation of σs in the aquatic bacterium shewanella oneidensis involves the crsr-crsa partner-switching regulatory system, but the exact mechanism by which crsr and ...201728729423
amplification of electrochemical signal by a whole-cell redox reactivation module for ultrasensitive detection of pyocyanin.a bioelectrochemical sensing system based on a novel whole-cell redox reactivation/cycling module for ultrasensitive detection of pyocyanin (the biomarker of pseudomonas aeruginosa infections) was developed. the electroactive bacteria mediated redox reactivation module was constructed using shewanella oneidensis mr-1 cells as the bioelectro-catalyst and lactate as the electron donor. it could regenerate reductive pyocyanin from its oxidative state, which enabled pyocyanin molecule repeatedly reg ...201728709085
anaerobic decolorization and detoxification of cationic red x-grl by shewanella oneidensis mr-1.the ability of a electrochemically active bacterium, shewanella oneidensis mr-1, to decolorize azo dye cationic red x-grl (x-grl) was investigated. s. oneidensis mr-1 showed a high decolorization capability for x-grl under anaerobic conditions. the mtr respiratory pathway was proved to be involved in the extracellular decolorization of x-grl. the decolorization efficiency of s. oneidensis mr-1 was significantly inhibited when initial x-grl concentration was over 200 mg l-1. increasing the inocul ...201728707516
extracellular polymeric substances are transient media for microbial extracellular electron transfer.microorganisms exploit extracellular electron transfer (eet) in growth and information exchange with external environments or with other cells. every microbial cell is surrounded by extracellular polymeric substances (eps). understanding the roles of three-dimensional (3d) eps in eet is essential in microbiology and microbial exploitation for mineral bio-respiration, pollutant conversion, and bioenergy production. we have addressed these challenges by comparing pure and eps-depleted samples of t ...201728695213
gaseous ligand selectivity of the h-nox sensor protein from shewanella oneidensis and comparison to those of other bacterial h-noxs and soluble guanylyl cyclase.to delineate the commonalities and differences in gaseous ligand discrimination among the heme-based sensors with heme nitric oxide/oxygen binding protein (h-nox) scaffold, the binding kinetic parameters for gaseous ligands no, co, and o2, including kd, kon, and koff, of shewanella oneidensis h-nox (so h-nox) were characterized in detail in this study and compared to those of previously characterized h-noxs from clostridium botulinum (cb h-nox), nostoc sp. (ns h-nox), thermoanaerobacter tengcong ...201728655588
thioesterase ybgc affects motility by modulating c-di-gmp levels in shewanella oneidensis.because of ubiquity of thioesters, thioesterases play a critical role in metabolism, membrane biosynthesis, signal transduction, and gene regulation. in many bacteria, ybgc is such an enzyme, whose coding gene mostly resides in the tol-pal cluster. although all other proteins encoded in the tol-pal cluster are clearly involved in maintaining cell envelope integrity and cell division, little is known about the physiological role of ybgc. in this study, we identify in shewanella oneidensis, a γ-pr ...201728638070
a high-throughput dye-reducing photometric assay for evaluating microbial exoelectrogenic ability.exoelectrogenic bacteria (eeb) can transfer electrons to extracellular electron acceptors and have wide applications in environmental bioremediation and bioenergy generation. thus, methods for effectively probing the exoelectrogenic ability of eeb are highly desirable. in this work, a simple but efficient photometric assay based on the extracellular reduction of high polar dyes was developed to evaluate the microbial exoelectrogenic ability. methyl orange were proven to be used as a probe for ev ...201728628978
cross-linked protein nanofilter with antibacterial properties for multifunctional air filtration.development of high-performance nanomaterials with not only strong ability to trap the pollutants but also good structure stability under varying environmental conditions is a critical need for air-filtration applications. however, it has been very challenging for a filtering material to simultaneously realize multifunctional air filtration and good environmental stability. here, based on our previous studies on protein-based nanofilters, we report a cross-linked protein nanofabric to address th ...201728628295
structures, compositions, and activities of live shewanella biofilms formed on graphite electrodes in electrochemical flow cells.an electrochemical flow cell equipped with a graphite working electrode (we) at the bottom was inoculated with shewanella oneidensis mr-1 expressing an anaerobic fluorescent protein, and biofilm formation on the we was observed over time during current generation at we potentials of +0.4 and 0 v (versus standard hydrogen electrodes), under electrolyte-flow conditions. electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.4-v biofilm. microscopic analyse ...201728625998
crispri-srna: transcriptional-translational regulation of extracellular electron transfer in shewanella oneidensis.extracellular electron transfer (eet) in shewanella oneidensis mr-1, which is one of the most well-studied exoelectrogens, underlies many microbial electrocatalysis processes, including microbial fuel cells, microbial electrolysis cells, and microbial electrosynthesis. however, regulating the efficiency of eet remains challenging due to the lack of efficient genome regulation tools that regulate gene expression levels in s. oneidensis. here, we systematically established a transcriptional regula ...201728616968
proton transport in the outer-membrane flavocytochrome complex limits the rate of extracellular electron transport.the microbial transfer of electrons to extracellularly located solid compounds, termed extracellular electron transport (eet), is critical for microbial electrode catalysis. although the components of the eet pathway in the outer membrane (om) have been identified, the role of electron/cation coupling in eet kinetics is poorly understood. we studied the dynamics of proton transport associated with eet in an om flavocytochrome complex in shewanella oneidensis mr-1. using a whole-cell electrochemi ...201728608645
discovery of two bacterial nitric oxide-responsive proteins and their roles in bacterial biofilm regulation.bacterial biofilms form when bacteria adhere to a surface and produce an exopolysaccharide matrix ( costerton science 1999 , 284 , 1318 ; davies science 1998 , 280 , 295 ; flemming nat. rev. microbiol. 2010 , 8 , 623 ). because biofilms are resistant to antibiotics, they are problematic in many aspects of human health and welfare, causing, for instance, persistent fouling of medical implants such as catheters and artificial joints ( brunetto chimia 2008 , 62 , 249 ). they are responsible for chr ...201728605194
living and conducting: coating individual bacterial cells with in situ formed polypyrrole.coating individual bacterial cells with conjugated polymers to endow them with more functionalities is highly desirable. here, we developed an in situ polymerization method to coat polypyrrole on the surface of individual shewanella oneidensis mr-1, escherichia coli, ochrobacterium anthropic or streptococcus thermophilus. all of these as-coated cells from different bacterial species displayed enhanced conductivities without affecting viability, suggesting the generality of our coating method. be ...201728590548
outer membrane cytochromes/flavin interactions in shewanella spp.-a molecular perspective.extracellular electron transfer (eet) is intrinsically associated with the core phenomena of energy harvesting/energy conversion in natural ecosystems and biotechnology applications. however, the mechanisms associated with eet are complex and involve molecular interactions that take place at the "bionano interface" where biotic/abiotic interactions are usually explored. this work provides molecular perspective on the electron transfer mechanism(s) employed by shewanella oneidensis mr-1. molecula ...201728565913
engineering a native inducible expression system in shewanella oneidensis to control extracellular electron transfer.shewanella oneidensis mr-1 is a model organism for understanding extracellular electron transport, in which cells transfer intracellular electrons to an extracellular terminal electron acceptor such as insoluble minerals or poised electrodes. biotechnological applications exploiting the respiratory capabilities of shewanella species have led to their proposed use in wastewater treatment, bioremediation, and remote sensors. transcriptional regulation tools can be used to rationally engineer s. on ...201728562022
crp regulates d-lactate oxidation in shewanella oneidensis mr-1.shewanella oneidensis mr-1 is a heterotrophic facultative anaerobe that respires using various organic and inorganic compounds. this organism has served as a model to study bacterial metabolic and regulatory systems that facilitate their survival in redox-stratified environments. the expression of many anaerobic respiratory genes in mr-1, including those for the reduction of fumarate, dimethyl sulfoxide, and metal oxides, is regulated by cyclic amp receptor protein (crp). however, relatively lit ...201728559887
bacterial physiology: hsp90 is the hot guy for shewanella oneidensis. 201728496161
optical elemental analysis of metals using shewanella oneidensis.a simple method for the detection of metal ions in solution is proposed, using shewanella oneidensis, which has the ability to reduce metal ions into metal nanoparticles on the cell surface. the method can be used to identify metal ions in solution using the light-scattering characteristics of the metal nanoparticles formed on the cells.201728496057
photovoltage response of (xzn)fe2o4-bifeo3 (x=mg, mn or ni) interfaces for highly selective cr3+, cd2+, co2+ and pb2+ ions detection.high-photostability fluorescent (xzn)fe2o4 (x=mg, mn or ni) embedded in bifeo3 spinel-perovskite nanocomposites were successfully fabricated via a novel bio-induced phase transfer method using shewanella oneidensis mr-1. these nanocomposites have the near-infrared fluorescence response (xzn or fe)-o-o-(bi) interfaces (785/832nm), and the (xzn)fe2o4/bifeo3 lattices with high/low potentials (572.15-808.77mev/206.43-548.1mev). our results suggest that heavy metal ion (cr3+, cd2+, co2+ and pb2+) d↓ ...201728494305
hsp90 is essential under heat stress in the bacterium shewanella oneidensis.the hsp90 chaperone is essential in eukaryotes and activates a large array of client proteins. in contrast, its role is still elusive in bacteria, and only a few hsp90 bacterial clients are known. here, we found that hsp90 is essential in the model bacterium shewanella oneidensis under heat stress. a genetic screen for hsp90 client proteins identified tils, an essential protein involved in trna maturation. overexpression of tils rescued the growth defect of the hsp90 deletion strain under heat s ...201728445720
anaerobic respiration on self-doped conjugated polyelectrolytes: impact of chemical structure.we probe anaerobic respiration of bacteria in the presence of conjugated polyelectrolytes (cpes). three different cpes were used to probe how structural variations impact biocurrent generation from shewanella oneidensis mr-1. for the self-doped anionic cpe only, absorption spectroscopy shows that the addition of s. oneidensis mr-1 leads to the disappearance of the polaron (radical cation) band at >900 nm and an increase in the band at 735 nm due to the neutral species, consistent with electron t ...201728444923
starch-fueled microbial fuel cells by two-step and parallel fermentation using shewanella oneidensis mr-1 and streptococcus bovis 148.shewanella oneidensis mr-1 generates electricity from lactic acid, but cannot utilize starch. on the other hand, streptococcus bovis 148 metabolizes starch and produces lactic acid. therefore, two methods were trialed for starch-fueled microbial fuel cell (mfc) in this study. in electric generation by two-step fermentation (egt) method, starch was first converted to lactic acid by s. bovis 148. the s. bovis 148 were then removed by centrifugation, and the fermented broth was preserved for electr ...201728434977
electrode assisted production of chemicals using shewanella oneidensis. 201728425632
enhancing extracellular electron transfer of shewanella oneidensis mr-1 through coupling improved flavin synthesis and metal-reducing conduit for pollutant degradation.dissimilatory metal reducing bacteria (dmrb) are capable of extracellular electron transfer (eet) to insoluble metal oxides, which are used as external electron acceptors by dmrb for their anaerobic respiration. the eet process has important contribution to environmental remediation mineral cycling, and bioelectrochemical systems. however, the low eet efficiency remains to be one of the major bottlenecks for its practical applications for pollutant degradation. in this work, shewanella oneidensi ...201728414427
dynamics in the dual fuel flagellar motor of shewanella oneidensis mr-1.the stator is an eminent component of the flagellar motor and determines a number of the motor's properties, such as the rotation-energizing coupling ion (h+ or na+) or the torque that can be generated. the stator consists of several units located in the cytoplasmic membrane surrounding the flagellar drive shaft. studies on flagellar motors of several bacterial species have provided evidence that the number as well as the retention time of stators coupled to the motor is highly dynamic and depen ...201728389963
a genome-scale model of shewanella piezotolerans simulates mechanisms of metabolic diversity and energy conservation.shewanella piezotolerans strain wp3 belongs to the group 1 branch of the shewanella genus and is a piezotolerant and psychrotolerant species isolated from the deep sea. in this study, a genome-scale model was constructed for wp3 using a combination of genome annotation, ortholog mapping, and physiological verification. the metabolic reconstruction contained 806 genes, 653 metabolites, and 922 reactions, including central metabolic functions that represented nonhomologous replacements between the ...201728382331
electrogenic single-species biocomposites as anodes for microbial fuel cells.integration of electrogenic microorganisms remains a challenge in biofuel cell technology. here, synthetic biocomposites ("artificial biofilms") are proposed. bacteria (shewanella oneidensis) are embedded in a hydrogel matrix (poly(vinyl alcohol)) via wet- and electrospinning, creating fibers and nonwoven gauzes. the bacteria remain viable and metabolically active. the performance is compared to s. oneidensis suspension cultures and "natural" biofilms. while lower than with the suspension cultur ...201728337840
electrode-assisted acetoin production in a metabolically engineered escherichia coli strain.this paper describes the metabolic engineering of escherichia coli for the anaerobic fermentation of glucose to acetoin. acetoin has well-established applications in industrial food production and was suggested to be a platform chemical for a bio-based economy. however, the biotechnological production is often hampered by the simultaneous formation of several end products in the absence of an electron acceptor. moreover, typical production strains are often potentially pathogenic. the goal of th ...201728293295
growth trade-offs accompany the emergence of glycolytic metabolism in shewanella oneidensis mr-1.bacteria increase their metabolic capacity via the acquisition of genetic material or by the mutation of genes already present in the genome. here, we explore the mechanisms and trade-offs involved when shewanella oneidensis, a bacterium that typically consumes small organic and amino acids, rapidly evolves to expand its metabolic capacity to catabolize glucose after a short period of adaptation to a glucose-rich environment. using whole-genome sequencing and genetic approaches, we discovered th ...201728289083
enhanced photocurrent production by the synergy of hematite nanowire-arrayed photoanode and bioengineered shewanella oneidensis mr-1.coupling the light-harvesting capabilities of semiconductors with the catalytic power of bacteria is a promising way to increase the efficiency of bioelectrochemical systems. here, we reported the enhanced photocurrents produced by the synergy of hematite nanowire-arrayed photoanode and the bio-engineered shewanella oneidensis mr-1 in a solar-assisted microbial photoelectrochemical system (solar mps) under the visible light. to increase the supply of bioelectrons, the d-lactate transporter, so15 ...201728285200
enhanced photovoltage response of hematite-x-ferrite interfaces (x = cr, mn, co, or ni).high-fluorescent p-x-ferrites (xfe2o4; xfo; x = fe, cr, mn, co, or ni) embedded in n-hematite (fe2o3) surfaces were successfully fabricated via a facile bio-approach using shewanella oneidensis mr-1. the results revealed that the x ions with high/low work functions modify the unpaired spin fe2+-o2- orbitals in the xfe2o4 lattices to become localized paired spin orbitals at the bottom of conduction band, separating the photovoltage response signals (73.36~455.16/-72.63~-32.43 mev). these (fe2o3)- ...201728235371
the role of riboflavin in decolourisation of congo red and bioelectricity production using shewanella oneidensis-mr1 under mfc and non-mfc conditions.dissimilatory metal reducing bacteria can exchange electrons extracellularly and hold great promise for their use in simultaneous wastewater treatment and electricity production. this study investigated the role of riboflavin, an electron carrier, in the decolourisation of congo red in microbial fuel cells (mfcs) using shewanella oneidensis mr-1 as a model organism. the contribution of the membrane-bound protein mtrc to the decolourisation process was also investigated. within the range of ribof ...201728229332
high performance reduction of h2o2 with an electron transport decaheme cytochrome on a porous ito electrode.the decaheme cytochrome mtrc from shewanella oneidensis mr-1 immobilized on an ito electrode displays unprecedented h2o2 reduction activity. although mtrc showed lower peroxidase activity in solution compared to horseradish peroxidase, the ten heme cofactors enable excellent electronic communication and a superior activity on the electrode surface. a hierarchical ito electrode enabled optimal immobilization of mtrc and a high current density of 1 ma cm(-2) at 0.4 v vs she could be obtained at ph ...201728221032
loss of oxyr reduces efficacy of oxygen respiration in shewanella oneidensis.in many bacteria, oxyr is the major regulator controlling cellular response to h2o2. a common phenotype resulting from oxyr loss is reduced growth rate, but the underlying mechanism is unknown. we demonstrated in shewanella oneidensis, an important research model for applied and environmental microbes, that the defect is primarily due to an electron shortage to major terminal oxidase cytochrome cbb3. the loss of oxyr leads to enhanced production of electron carriers that compete for electrons ag ...201728195212
investigation concerning the formation process of gold nanoparticles by shewanella oneidensis mr-1.shewanella oneidensis mr-1 is a facultative anaerobic bacterium that is known to transfer electrons generated during metabolism to various metal ions and produce nanoparticles on the bacterial surface. in this study, we tracked the formation of gold nanoparticles (au nps) on the s. oneidensis cell surfaces and investigated the roles of membrane proteins and extracellular polysaccharides in this process by spectrometry, zeta potential analysis, and electron microscopy.201728190828
nitric oxide-induced conformational changes govern h-nox and histidine kinase interaction and regulation in shewanella oneidensis.nitric oxide (no) is implicated in biofilm regulation in several bacterial families via heme-nitric oxide/oxygen binding (h-nox) protein signaling. shewanella oneidensis h-nox (so h-nox) is associated with a histidine kinase (so hnok) encoded on the same operon, and together they form a multicomponent signaling network whereby the no-bound state of so h-nox inhibits so hnok autophosphorylation activity, affecting the phosphorylation state of three response regulators. although the conformational ...201728170222
a class c radical s-adenosylmethionine methyltransferase synthesizes 8-methylmenaquinone.the membranous quinone/quinol pool is essential to the majority of life forms and has been widely used as an important biomarker in microbial taxonomy. in the anaerobic world, the most important quinones are menaquinone (mk) and a methylated form of mk, designated methylmenaquinone (mmk), which is anticipated to serve specifically in low-potential electron transport chains involved in anaerobic respiration. however, it has remained unclear how mmk is generated. here, we show that a novel enzyme ...201728164386
integrated microfluidic flow-through microbial fuel cells.this paper reports on a miniaturized microbial fuel cell with a microfluidic flow-through configuration: a porous anolyte chamber is formed by filling a microfluidic chamber with three-dimensional graphene foam as anode, allowing nutritional medium to flow through the chamber to intimately interact with the colonized microbes on the scaffolds of the anode. no nutritional media flow over the anode. this allows sustaining high levels of nutrient utilization, minimizing consumption of nutritional s ...201728120875
comparative stability of major facilitator superfamily transport proteins.membrane transporters are a vital class of proteins for which there is little available structural and thermodynamic information. the major facilitator superfamily (mfs) is a large group of transport proteins responsible for transporting a wide range of substrates in eukaryotes and prokaryotes. we have used far-uv circular dichroism (cd) to assess whether transporters from this superfamily have the same chemical and thermal stability. we have compared the stability of five different mfs transpor ...201728116476
cometabolic degradation of chloramphenicol via a meta-cleavage pathway in a microbial fuel cell and its microbial community.the performance of a microbial fuel cell (mfc) in terms of degradation of chloramphenicol (cap) was investigated. approximately 84% of 50mg/l cap was degraded within 12h in the mfc. a significant interaction of ph, temperature, and initial cap concentration was found on removal of cap, and a maximum degradation rate of 96.53% could theoretically be achieved at 31.48°c, a ph of 7.12, and an initial cap concentration of 106.37mg/l. moreover, cap was further degraded through a ring-cleavage pathway ...201728110226
a near-infrared light responsive c-di-gmp module-based and logic gate in shewanella oneidensis.a novel, biofilm-based and logic gate was constructed in shewanella oneidensis through a near-infrared (nir) light responsive c-di-gmp module. the logic gate was demonstrated in microbial fuel cells with isopropyl β-d-thiogalactoside (iptg) and nir light as the inputs and electrical signals as the output.201728098272
resilience, dynamics, and interactions within a model multispecies exoelectrogenic-biofilm community.anode-associated multispecies exoelectrogenic biofilms are essential for the function of bioelectrochemical systems (bess). the individual activities of anode-associated organisms and physiological responses resulting from coculturing are often hard to assess due to the high microbial diversity in these systems. therefore, we developed a model multispecies biofilm comprising three exoelectrogenic proteobacteria, shewanella oneidensis, geobacter sulfurreducens, and geobacter metallireducens, with ...201728087529
quantification of free polyelectrolytes present in colloidal suspension, revealing a source of toxic responses for polyelectrolyte-wrapped gold nanoparticles.polyelectrolyte (pe) wrapping of colloidal nanoparticles (nps) is a standard method to control np surface chemistry and charge. because excess polyelectrolytes are usually employed in the surface modification process, it is critical to evaluate different purification strategies to obtain a clean final product and thus avoid ambiguities in the source of effects on biological systems. in this work, 4 nm diameter gold nanoparticles (aunps) were wrapped with 15 kda poly(allylamine hydrochloride) (pa ...201728078889
transcriptome and metabolome responses of shewanella oneidensis mr-1 to methyl orange under microaerophilic and aerobic conditions.shewanella oneidensis mr-1 degrades various azo dyes under microaerophilic and anaerobic conditions, but this process is inhibited under aerobic conditions. the mechanisms underlying azo dye biodegradation and inhibition remain unknown. therefore, we investigated metabolic and transcriptional changes in strain mr-1, which was cultured under different conditions, to elucidate these mechanisms. at the transcriptional level, genes involved in certain metabolic processes, particularly the tricarboxy ...201728070664
acetoin production via unbalanced fermentation in shewanella oneidensis.this study describes the realization of an anoxic acetoin production process using the proteobacterium shewanella oneidensis. fermentative processes are of high biotechnological relevance since they offer high productivity and a low percentage of substrate consumption for anabolic processes. nevertheless, the range of compounds that can be produced as sole end product of a fermentative process is limited, since the average oxidation state of substrate and products has to be identical in the abse ...201728059435
biological recovery of platinum complexes from diluted aqueous streams by axenic cultures.the widespread use of platinum in high-tech and catalytic applications has led to the production of diverse pt loaded wastewaters. effective recovery strategies are needed for the treatment of low concentrated waste streams to prevent pollution and to stimulate recovery of this precious resource. the biological recovery of five common environmental pt-complexes was studied under acidic conditions; the chloro-complexes ptcl42- and ptcl62-, the amine-complex pt(nh3)4cl2 and the pharmaceutical comp ...201728046131
microbial synthesis of bimetallic pdpt nanoparticles for catalytic reduction of 4-nitrophenol.bimetallic nanoparticles are generally believed to have improved catalytic activity and stability due to geometric and electronic changes. in this work, biogenic-pd (bio-pd), biogenic-pt (bio-pt), and biogenic-pdpt (bio-pdpt) nanoparticles were synthesized by shewanella oneidensis mr-1 in the absence or presence of quinone. compared with direct microbial reduction process, the addition of anthraquinone-2,6-disulfonate (aqds) could promote the reduction efficiency of pd(ii) or/and pt(iv) and resu ...201728004366
the detoxification and degradation of benzothiazole from the wastewater in microbial electrolysis cells.in this study, the high-production-volume chemical benzothiazole (bth) from synthetic water was fully degraded into less toxic intermediates of simple organic acids using an up-flow internal circulation microbial electrolysis reactor (uicmer) under the hydraulic retention time (hrt) of 24 h. the bioelectrochemical system was operated at 25 ± 2 °c and continuous-flow mode. the bth loading rate varied during experiments from 20 g·m(-3)·day(-1) to 110 g·m(-3)·day(-1). bth and soluble cod (chemical ...201627999421
effective methods for extracting extracellular polymeric substances from shewanella oneidensis mr-1.extracellular polymeric substances (eps) play crucial roles in bio-aggregate formation and survival of bacterial cells. to develop an effective but harmless method for eps extraction from shewanella oneidensis mr-1, five extraction methods, i.e. centrifugation (control), heating (40, 45, 50, and 60 °c), and treatments with h2so4, ethylenediaminetetraacetic acid (edta) and naoh, were examined, respectively. results from scanning electron microscope and flow cytometric analyses indicate that mr-1 ...201627997408
redox properties of extracellular polymeric substances (eps) from electroactive bacteria.although the capacity for electroactive bacteria to convert environmental metallic minerals and organic pollutants is well known, the role of the redox properties of microbial extracellular polymeric substances (eps) in this process is poorly understood. in this work, the redox properties of eps from two widely present electroactive bacterial strains (shewanella oneidensis and pseudomonas putida) were explored. electrochemical analysis demonstrates that the eps extracted from the two strains exh ...201627991531
computing and applying atomic regulons to understand gene expression and regulation.understanding gene function and regulation is essential for the interpretation, prediction, and ultimate design of cell responses to changes in the environment. an important step toward meeting the challenge of understanding gene function and regulation is the identification of sets of genes that are always co-expressed. these gene sets, atomic regulons (ars), represent fundamental units of function within a cell and could be used to associate genes of unknown function with cellular processes an ...201627933038
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