Extracellular redox-active compounds, flavins and other quinones, have been hypothesized to play a major role in the delivery of electrons from cellular metabolic systems extracellular insoluble substrates by diffusion-based shuttling two-electron-transfer mechanism. Here we show that flavin molecules secreted Shewanella oneidensis MR-1 enhance ability its outer-membrane c -type cytochromes (OM c- Cyts) transport as redox cofactors, but not free-form flavins. Whole-cell differential pulse...

Iron is a micronutrient for nearly all life on Earth. It can be used as an electron donor and acceptor by iron-oxidizing iron-reducing microorganisms in variety of biological processes, including photosynthesis respiration. While it the fourth most abundant metal Earth's crust, iron often limiting growth oxic environments because readily oxidized precipitated. Much our understanding how compete utilize based laboratory experiments. However, advent next-generation sequencing surge publicly...

Microbially influenced corrosion (MIC), is acknowledged to be the direct cause of catastrophic failures, with associated damage costs ranging many billions US$ annually. In spite extensive research and numerous publications, fundamental questions relating MIC remain unanswered. The following review provides an overview current stresses lack information related recognition, prediction mitigation. establishes a link between management decisions root causes. A holistic, proactive approach...

<italic>Geobacter</italic> cells utilize self-secreted riboflavin as a bound-cofactor in outer-membrane <italic>c</italic>-type cytochromes to enhance the rate of bacterial electron transport.

Bacterial reduction of oxidized sulfur species (OSS) is critical for energy production in anaerobic marine subsurfaces. In organic-poor sediments, H2 has been considered as a major source bacterial respiration. We identified outer-membrane cytochromes (OMCs) that are broadly conserved sediment OSS-respiring bacteria and enable cells to directly use electrons from insoluble minerals via extracellular electron transport. Biochemical, transcriptomic, microscopic analyses revealed the OMCs were...

Protein power grids: A metal-reducing bacterium, Shewanella loihica PV-4, has the ability to self-organize an electrically conductive network using outer-membrane proteins and semiconductive minerals as a long-distance electron transfer conduit. Detailed facts of importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by authors. Please note: The publisher is responsible for content...

The first photocatalysis operated by the visible-light induced metal-to-metal charge transfer (MMCT) has been demonstrated for Ti(IV)/Ce(III) bimetallic assemblies synthesized on pore of mesoporous silica. Ce LIII-edge XANES measurements combined with 18O-isotopic labeling as well photoelectrochemical experiments proved ability to drive site-specific photocatalytic reaction under irradiation. Photocatalytic using oxidative decomposition 2-propanol showed that quantum efficiency...

Abstract 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 -Cyts) expands the importance microbial respiration in natural environments industrial applications. Here, we demonstrate that bifurcated EET pathway OM -Cyts sustains diversity surface Shewanella oneidensis MR-1 specific binding with cell-secreted flavin mononucleotide (FMN) riboflavin (RF). Microbial current...

While typically investigated as a microorganism capable of extracellular electron transfer to minerals or anodes, Shewanella oneidensis MR-1 can also facilitate flow from cathode terminal acceptors, such fumarate oxygen, thereby providing model system for process that has significant environmental and technological implications. This work demonstrates cathodic electrons enter the transport chain S. when oxygen is used acceptor. The effect inhibitors suggested proton gradient generated during...

Abstract 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 OM ‐Cyts to an anode is well understood, how take electrons cathode not been elucidated at molecular level. Electrochemical analysis of live cells during switching anodic cathodic conditions showed that altering direction flow does require gene...

Abstract Certain microbes are capable of transporting electrons from the cell interior‐respiratory electron chain to insoluble acceptors located outside cell, a process referred as extracellular transport (EET). Bacteria EET currently utilized “living anode catalysts” in microbial fuel cells. Several mechanisms have been proposed, yet they lack molecular‐level consistency. Here, we review our recent work, presenting “bound‐flavin cofactor” model, which believe provides suitable explanation...

Little is known about the importance and/or mechanisms of biological mineral oxidation in sediments, partially due to difficulties associated with culturing mineral-oxidizing microbes. We demonstrate that electrochemical enrichment a feasible approach for isolation microbes capable gaining electrons from insoluble minerals. To this end we constructed sediment microcosms and incubated electrodes at various controlled redox potentials. Negative current production was observed incubations...

Microbes synthesize cell-associated nanoparticles (NPs) and utilize their physicochemical properties to produce energy under unfavorable metabolic conditions. Iron sulfide (FeS) NPs are ubiquitous predominantly biosynthesized by sulfate-reducing bacteria (SRB). However, the biological role of FeS in SRB remains understudied. Now, conductive function is demonstrated as an electron conduit enabling Desulfovibrio vulgaris Hildenborough, strain, solid-state donors via direct uptake. After...

We review recent developments in theories and experiments on the magnon Hall effect. derive thermal conductivity of magnons terms Berry curvature magnonic bands. In addition to Dzyaloshinskii–Moriya interaction, we show that dipolar interaction can make nonzero. mainly discuss theoretical aspects effect related works. Experimental progress this field is also mentioned.

Directed evolution was used to change the substrate specificity of aspartate aminotransferase. A mutant enzyme with 17 amino acid substitutions generated that shows a 2.1 x 10(6)-fold increase in catalytic efficiency (kcat/Km) for non-native substrate, valine. The absorption spectrum bound coenzyme, pyridoxal 5'-phosphate, is also changed significantly by mutations. Interestingly, only one residues appears be able contact and none them interact coenzyme. three-dimensional structure complexed...

We determined the three-dimensional structures of aspartate aminotransferase (AspAT) from Escherichia coli and its complex with inhibitor (2-methyl-L-aspartate) at 1.8 Å resolution. This enzyme reversibly catalyzes transamination reaction is a dimer two identical subunits. Each subunit has 396 amino acid residues one pyridoxal 5'-phosphate as cofactor, divided into domains, large other small. Upon binding inhibitor, small domain rotates by 5° toward to close active site. movement caused...

In addition to serving as an energy source for microbial growth, iron sulfides are proposed act naturally occurring electrical wires that mediate long-distance extracellular electron transfer (EET) and bridge spatially discrete redox environments. These hypothetical EET reactions stand on the abilities of microbes use interfacial electrochemistry metallic/semiconductive maintain metabolisms; however, mechanisms these phenomena remain unexplored. To obtain insight into sulfides, we monitored...

In an attempt to identify unknown target genes for SREBP-1, total RNA from a stable Chinese hamster ovary cell line (CHO-487) expressing mature form of human SREBP-1a (amino acids 1–487) with LacSwitch Inducible Mammalian Expression System was subjected polymerase chain reaction subtraction method. One the fragments found have 90 and 86% homology rat ATP citrate-lyase (ACL) cDNA, respectively. When Hep G2 cells are cultured under either sterol-loaded or -depleted conditions, expression gene...

Although nanocrystalline Fe(III) oxides are abundant in natural minerals, few studies have noticed their biological significance from the view point of semiconductive properties. To examine roles respiratory activity microorganisms, we cultured Fe(III)-reducing bacterium Shewanella loihica PV-4 an electrochemical cell and examined influence surface-associated Fe-oxide nanocolloids on extracellular electron transfer (EET) efficiency. It was found that current greatly improved (over 40 fold)...