scholarly journals Long-distance electron transport in individual, living cable bacteria

2018 ◽  
Vol 115 (22) ◽  
pp. 5786-5791 ◽  
Author(s):  
Jesper T. Bjerg ◽  
Henricus T. S. Boschker ◽  
Steffen Larsen ◽  
David Berry ◽  
Markus Schmid ◽  
...  
Keyword(s):  
Electron Transport ◽  
Laser Cutting ◽  
Direct Evidence ◽  
Living Cells ◽  
Long Distance ◽  
Bacteria Transport ◽  
Redox States ◽  
Photosynthetic Organisms ◽  
Electron Sink ◽  
Rapid Shift

Electron transport within living cells is essential for energy conservation in all respiring and photosynthetic organisms. While a few bacteria transport electrons over micrometer distances to their surroundings, filaments of cable bacteria are hypothesized to conduct electric currents over centimeter distances. We used resonance Raman microscopy to analyze cytochrome redox states in living cable bacteria. Cable-bacteria filaments were placed in microscope chambers with sulfide as electron source and oxygen as electron sink at opposite ends. Along individual filaments a gradient in cytochrome redox potential was detected, which immediately broke down upon removal of oxygen or laser cutting of the filaments. Without access to oxygen, a rapid shift toward more reduced cytochromes was observed, as electrons were no longer drained from the filament but accumulated in the cellular cytochromes. These results provide direct evidence for long-distance electron transport in living multicellular bacteria.

scholarly journals Flavodiiron proteins act as safety valve for electrons in Physcomitrella patens

2016 ◽  
Vol 113 (43) ◽  
pp. 12322-12327 ◽  
Author(s):  
Caterina Gerotto ◽  
Alessandro Alboresi ◽  
Andrea Meneghesso ◽  
Martina Jokel ◽  
Marjaana Suorsa ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Physcomitrella Patens ◽  
Safety Valve ◽  
Cell Metabolism ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Flowering Plants ◽  
Knock Out ◽  
Electron Sink

Photosynthetic organisms support cell metabolism by harvesting sunlight to fuel the photosynthetic electron transport. The flow of excitation energy and electrons in the photosynthetic apparatus needs to be continuously modulated to respond to dynamics of environmental conditions, and Flavodiiron (FLV) proteins are seminal components of this regulatory machinery in cyanobacteria. FLVs were lost during evolution by flowering plants, but are still present in nonvascular plants such as Physcomitrella patens. We generated P. patens mutants depleted in FLV proteins, showing their function as an electron sink downstream of photosystem I for the first seconds after a change in light intensity. flv knock-out plants showed impaired growth and photosystem I photoinhibition when exposed to fluctuating light, demonstrating FLV’s biological role as a safety valve from excess electrons on illumination changes. The lack of FLVs was partially compensated for by an increased cyclic electron transport, suggesting that in flowering plants, the FLV’s role was taken by other alternative electron routes.

scholarly journals Spin-Dependent Electron Transport through Bacterial Cell Surface Multiheme Electron Conduits

2019 ◽  
Author(s):  
Suryakant Mishra ◽  
Sahand Pirbadian ◽  
Amit Kumar Mondal ◽  
Moh El-Naggar ◽  
Ron Naaman
Keyword(s):  
Electron Transport ◽  
Cell Surface ◽  
Bacterial Cell ◽  
Shewanella Oneidensis ◽  
Extracellular Electron Transfer ◽  
Long Distance ◽  
Force Microscopy ◽  
Bacterial Cell Surface ◽  
Redox Active ◽  
Gain Energy

Multiheme cytochromes, located on the bacterial cell surface, function as long-distance (> 10 nm) electron conduits linking intracellular reactions to external surfaces. This extracellular electron transfer process, which allows microorganisms to gain energy by respiring solid redox-active minerals, also facilitates the wiring of cells to electrodes. While recent studies suggested that a chiral induced spin selectivity effect is linked to efficient electron transmission through biomolecules, this phenomenon has not been investigated in the extracellular electron conduits. Using magnetic conductive probe atomic force microscopy, Hall voltage measurements, and spin-dependent electrochemistry of the decaheme cytochromes MtrF and OmcA from the metal-reducing bacterium <i>Shewanella oneidensis</i> MR-1, we show that electron transport through these extracellular conduits is spin-selective. Our study has implications for understanding how spin-dependent interactions and magnetic fields may control electron transport across biotic-abiotic interfaces in both natural and biotechnological systems.

scholarly journals Supplementary material to "Long-distance electron transport occurs globally in marine sediments"

2016 ◽  
Author(s):  
Laurine D. W. Burdorf ◽  
Anton Tramper ◽  
Dorina Seitaj ◽  
Lorenz Meire ◽  
Silvia Hidalgo-Martinez ◽  
...  
Keyword(s):  
Electron Transport ◽  
Marine Sediments ◽  
Long Distance ◽  
Supplementary Material

The influence of the water surrounding on a long-distance electron transport in the DNA

2008 ◽  
Vol 5 (3) ◽  
pp. 714-717
Author(s):  
J. Matulewski ◽  
S. Orłowski ◽  
S. D. Baranovskii ◽  
P. Thomas
Keyword(s):  
Electron Transport ◽  
Long Distance

scholarly journals Imaging kinase–AKAP79–phosphatase scaffold complexes at the plasma membrane in living cells using FRET microscopy

2002 ◽  
Vol 160 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Seth F. Oliveria ◽  
Lisa L. Gomez ◽  
Mark L. Dell'Acqua
Keyword(s):  
Signal Transduction ◽  
Glutamate Receptors ◽  
Direct Evidence ◽  
Protein A ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Adaptor Proteins ◽  
Living Cells ◽  
Intact Cells ◽  
Anchoring Protein

Scaffold, anchoring, and adaptor proteins coordinate the assembly and localization of signaling complexes providing efficiency and specificity in signal transduction. The PKA, PKC, and protein phosphatase-2B/calcineurin (CaN) scaffold protein A–kinase anchoring protein (AKAP) 79 is localized to excitatory neuronal synapses where it is recruited to glutamate receptors by interactions with membrane-associated guanylate kinase (MAGUK) scaffold proteins. Anchored PKA and CaN in these complexes could have important functions in regulating glutamate receptors in synaptic plasticity. However, direct evidence for the assembly of complexes containing PKA, CaN, AKAP79, and MAGUKs in intact cells has not been available. In this report, we use immunofluorescence and fluorescence resonance energy transfer (FRET) microscopy to demonstrate membrane cytoskeleton–localized assembly of this complex. Using FRET, we directly observed binding of CaN catalytic A subunit (CaNA) and PKA-RII subunits to membrane-targeted AKAP79. We also detected FRET between CaNA and PKA-RII bound simultaneously to AKAP79 within 50 Å of each other, thus providing the first direct evidence of a ternary kinase–scaffold–phosphatase complex in living cells. This finding of AKAP-mediated PKA and CaN colocalization on a nanometer scale gives new appreciation to the level of compartmentalized signal transduction possible within scaffolds. Finally, we demonstrated AKAP79-regulated membrane localization of the MAGUK synapse-associated protein 97 (SAP97), suggesting that AKAP79 functions to organize even larger signaling complexes.

scholarly journals The geochemical fingerprint of microbial long-distance electron transport in the seafloor

2015 ◽  
Vol 152 ◽  
pp. 122-142 ◽  
Author(s):  
Filip J.R. Meysman ◽  
Nils Risgaard-Petersen ◽  
Sairah Y. Malkin ◽  
Lars Peter Nielsen
Keyword(s):  
Electron Transport ◽  
Long Distance ◽  
Geochemical Fingerprint

Toward understanding long-distance extracellular electron transport in an electroautotrophic microbial community

2016 ◽  
Vol 9 (11) ◽  
pp. 3544-3558 ◽  
Author(s):  
Matthew D. Yates ◽  
Brian J. Eddie ◽  
Nicholas J. Kotloski ◽  
Nikolai Lebedev ◽  
Anthony P. Malanoski ◽  
...  
Keyword(s):  
Microbial Community ◽  
Electron Transport ◽  
Long Distance ◽  
Extracellular Electron Transport

Here we show that long-distance extracellular electron transport occurs in a cathodic biofilm capable of CO2 fixation and O2 respiration.

scholarly journals Regulation of electron transport is essential for photosystem I stability and plant growth

2019 ◽  
Author(s):  
Mattia Storti ◽  
Anna Segalla ◽  
Marco Mellon ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Nadh Dehydrogenase ◽  
Physcomitrella Patens ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Type I ◽  
Growth Reduction ◽  
Light Regimes ◽  
Photosynthetic Organisms

AbstractLife depends on the ability of photosynthetic organisms to exploit sunlight to fix carbon dioxide into biomass. Photosynthesis is modulated by pathways such as cyclic and pseudocyclic electron flow (CEF and PCEF). CEF transfers electrons from photosystem I to the plastoquinone pool according to two mechanisms, one dependent on proton gradient regulators (PGR5/PGRL1) and the other on the type I NADH dehydrogenase (NDH) complex. PCEF uses electrons from photosystem I to reduce oxygen; in several groups of photosynthetic organisms but not in angiosperms, it is sustained by flavodiiron proteins (FLVs). PGR5/PGRL1, NDH and FLVs are all active in the moss Physcomitrella patens, and mutants depleted in these proteins show phenotypes under specific light regimes. Here, we demonstrated that CEF and PCEF exhibit strong functional overlap and that when one protein component is depleted, the others can compensate for most of the missing activity. When multiple mechanisms are simultaneously inactivated, however, plants show damage to photosystem I and strong growth reduction, demonstrating that mechanisms for the modulation of photosynthetic electron transport are indispensable.

scholarly journals Outstanding Photo-bioelectrochemical Cell by Integrating TiO2 and Chlorophyll as Photo-bioanode for Sustainable Energy Generation

2021 ◽  
Vol 11 (2) ◽  
pp. 385-391
Author(s):  
Marcelinus Christwardana ◽  
Athanasia Amanda Septevani ◽  
Linda Aliffia Yoshi
Keyword(s):  
Electron Transport ◽  
Chlorophyll Content ◽  
Water Oxidation ◽  
Spirulina Platensis ◽  
Chlorophyll Concentration ◽  
Photocurrent Density ◽  
The Other ◽  
Trapping Efficiency ◽  
Photosynthetic Organisms ◽  
Distinctive Structure

Photosynthesis is a technique for converting light energy into chemical energy that is both efficient and sustainable. Chlorophyll in energy-transducing photosynthetic organisms is unique because of their distinctive structure and composition. In photo-bioelectrochemical research, the chlorophyll's quantum trapping efficiency is attractive. Chlorophyll from Spirulina platensis is demonstrated to communicate directly with TiO2-modified Indium Thin Oxide (ITO) to generate electricity without the use of any mediator. TiO2-modified ITO with a chlorophyll concentration of 100 % generated the greatest power density and photocurrent of approximately 178.15 mW/m2 and 596.92 mA/m2 from water oxidation under light among all the other materials. While the sensitivity with light was 0.885 mA/m2.lux, and Jmax value was 1085 mA/m2. Furthermore, the power and photocurrent density as a function of chlorophyll content are studied. The polarizability and Van der Waals interaction of TiO2 and chlorophyll are crucial in enhancing electron transport in photo-bioelectrochemical systems. As a result, this anode structure has the potential to be improved and used to generate even more energy.

scholarly journals Long-distance electron transport by cable bacteria in mangrove sediments

2016 ◽  
Vol 545 ◽  
pp. 1-8 ◽  
Author(s):  
LDW Burdorf ◽  
S Hidalgo-Martinez ◽  
PLM Cook ◽  
FJR Meysman
Keyword(s):  
Electron Transport ◽  
Mangrove Sediments ◽  
Long Distance
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