Comparative Proteomics Implicates a Role for Multiple Secretion Systems in Electrode-Respiring <i>Geobacter sulfurreducens</i> Biofilms

Kavanagh, Paul; Botting, Catherine H.; Jana, Partha Sarathi; Leech, Dónal; Abram, Florence

doi:10.1021/acs.jproteome.5b01019

Cited by 10 publications

(10 citation statements)

References 62 publications

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“…Transcriptomic and proteomic analyses have previously been performed to identify important genes for EET in G. sulfurreducens ( Holmes et al, 2006 ; Ding et al, 2008 ; Nevin et al, 2009 ; Aklujkar et al, 2013 ; Kavanagh et al, 2016 ). Here, we compared important genes (including previously reported genes or those identified in this study) for EET in G. soli and G. sulfurreducens at both transcript and translation levels.…”

Section: Discussionmentioning

confidence: 99%

“…However, a number of other c -Cyts and PilA proteins that were upregulated in G. sulfurreducens were unchanged in G. soli (Supplementary Figure S4a ). Comparative proteomics of G. sulfurreducens indicated that proteins associated with multiple secretion systems, such as PulQ and PulE, are particularly important for electron-conducting biofilms vs. planktonic cells (Supplementary Figure S4b ) ( Kavanagh et al, 2016 ). However, these proteins, with the exception of the Type IV pilus secretion lipoprotein PilQ, were unchanged in G. soli .…”

Section: Discussionmentioning

confidence: 99%

“…Current evidence from studies with G. sulfurreducens has revealed that EET occurs through the redox proteins, such as c -type cytochromes ( c -Cyts) and multicopper proteins ( Nevin et al, 2009 ; Holmes et al, 2008 ; Kumar et al, 2017 ), or through electrically conductive pili (known as nanowires) ( Reguera et al, 2005 ). Interplay of these redox proteins and nanowires forms multiple electron conduits in the genus Geobacter to support diverse electron transfer processes, and distinctive proteins are involved in the EET process when cells are grown with different electron acceptors ( Nevin et al, 2009 ; Kavanagh et al, 2016 ). For example, c -Cyts PgcA can facilitate electron transfer to Fe(III) oxides but not electrodes ( Zacharoff et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

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Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

et al. 2018

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The ability of Geobacter species to transfer electrons outside cells enables them to play an important role in biogeochemical and bioenergy processes. Our knowledge of the extracellular electron transfer (EET) process in the genus Geobacter is mainly from the study of G. sulfurreducens, and in order to fully investigate the EET mechanisms in the genus Geobacter, other Geobacter species should also be considered. This study focused on the EET of Geobacter soli GSS01, which exhibited a capability of reducing insoluble Fe(III) oxides and generating electrical current comparable with G. sulfurreducens PCA. Electrochemical characterization, including cyclic voltammetry, differential pulse voltammetry, and electrochemical in situ FTIR spectra, revealed that different redox proteins contributed to the electrochemical behaviors of G. soli and G. sulfurreducens. Based on comparative transcriptomic and proteomic analyses, OmcS was the most upregulated protein in both G. soli and G. sulfurreducens cells grown with insoluble Fe(III) oxides vs. soluble electron acceptor. However, the proteins including OmcE and PilA that were previously reported as being important for EET in G. sulfurreducens were downregulated or unchanged in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, and many proteins that were upregulated in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, such as OmcN, are not important for EET in G. sulfurreducens. We also identified 30 differentially expressed small RNAs (sRNAs) in G. soli cells grown with different acceptors. Taken together, these findings help to understand the versatile EET mechanisms that exist in the genus Geobacter and point to the possibility of sRNA in modulating EET gene expression.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

et al. 2018

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“…Flagella—such as FliC, a Geobacter UDPI in the present study—have been associated with biofilm proliferation [ 91 ] as well as with current generation [ 79 ] or dissimilatory respiration of iron oxides by Geobacter [ 92 ]. Future work could take a strain-resolved proteomics approach [ 93 ] to comparing protein expression in BESs by Geobacter in pure culture [ 27 ] or as a dominant member of a constrained community to that as part of a diverse consortium. Such an approach could identify differences in the role of Geobacter role or mechanisms of action when involved with different types of communities, and perhaps identify mechanisms of antagonism against competitors, especially during MFC startup.…”

Section: Discussionmentioning

confidence: 99%

“…These “meta-proteomics” studies have identified metabolic mechanisms behind multispecies fermentation [ 23 ], methanogenesis [ 24 ], or community response to a toxic perturbation [ 25 ]. A few studies have used proteomics methods to investigate electricity generation by model species or isolates [ 26 , 27 ]. Meta-proteomics examinations of BES systems, however, have been limited to a single investigation of protein expression of biocathode biofilm organisms under optimal and suboptimal conditions [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Meta-proteomic analysis of protein expression distinctive to electricity-generating biofilm communities in air-cathode microbial fuel cells

Chignell

Long

Reardon

2018

Biotechnol Biofuels

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BackgroundBioelectrochemical systems (BESs) harness electrons from microbial respiration to generate power or chemical products from a variety of organic feedstocks, including lignocellulosic biomass, fermentation byproducts, and wastewater sludge. In some BESs, such as microbial fuel cells (MFCs), bacteria living in a biofilm use the anode as an electron acceptor for electrons harvested from organic materials such as lignocellulosic biomass or waste byproducts, generating energy that may be used by humans. Many BES applications use bacterial biofilm communities, but no studies have investigated protein expression by the anode biofilm community as a whole.ResultsTo discover functional protein expression during current generation that may be useful for MFC optimization, a label-free meta-proteomics approach was used to compare protein expression in acetate-fed anode biofilms before and after the onset of robust electricity generation. Meta-proteomic comparisons were integrated with 16S rRNA gene-based community analysis at four developmental stages. The community composition shifted from dominance by aerobic Gammaproteobacteria (90.9 ± 3.3%) during initial biofilm formation to dominance by Deltaproteobacteria, particularly Geobacter (68.7 ± 3.6%) in mature, electricity-generating anodes. Community diversity in the intermediate stage, just after robust current generation began, was double that at the early stage and nearly double that of mature anode communities. Maximum current densities at the intermediate stage, however, were relatively similar (~ 83%) to those achieved by mature-stage biofilms. Meta-proteomic analysis, correlated with population changes, revealed significant enrichment of categories specific to membrane and transport functions among proteins from electricity-producing biofilms. Proteins detected only in electricity-producing biofilms were associated with gluconeogenesis, the glyoxylate cycle, and fatty acid β-oxidation, as well as with denitrification and competitive inhibition.ConclusionsThe results demonstrate that it is possible for an MFC microbial community to generate robust current densities while exhibiting high taxonomic diversity. Moreover, these data provide evidence to suggest that startup growth of air–cathode MFCs under conditions that promote the establishment of aerobic–anaerobic syntrophy may decrease startup times. This study represents the first investigation into protein expression of a complex BES anode biofilm community as a whole. The findings contribute to understanding of the molecular mechanisms at work during BES startup and suggest options for improvement of BES generation of bioelectricity from renewable biomass.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1111-2) contains supplementary material, which is available to authorized users.

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Harnessing the Extracellular Electron Transfer Capability of Geobacter sulfurreducens for Ambient Synthesis of Stable Bifunctional Single‐Atom Electrocatalyst for Water Splitting

Pedireddy

Jimenez-Sandoval

Ravva

et al. 2021

Adv Funct Materials

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Single-atom metal (SA-M) catalysts with high dispersion of active metal sites allow maximum atomic utilization. Conventional synthesis of SA-M catalysts involves high-temperature treatments, leading to low yield with a random distribution of atoms. Herein, a nature-based facile method to synthesize SA-M catalysts (M = Fe, Ir, Pt, Ru, Cu, or Pd) in a single step at ambient temperature, using the extracellular electron transfer capability of Geobacter sulfurreducens (GS), is presented. Interestingly, the SA-M is coordinated to three nitrogen atoms adopting an MN 3 on the surface of GS. Dry samples of SA-Ir@GS without further heat treatment show exceptionally high activity for oxygen evolution reaction when compared to benchmark IrO 2 catalyst and comparable hydrogen evolution reaction activity to commercial 10 wt% Pt/C. The SA-Ir@GS exhibits the best water-splitting performance compared to other SA-M@GS, showing a low applied potential of 1.65 V to achieve 10 mA cm −2 in 1.0 M KOH with cycling over 5 h. The density functional calculations reveal that the large adsorption energy of H 2 O and moderate adsorption energies of reactants and reaction intermediates for SA-Ir@GS favorably improve its activity. This synthesis method at room temperature provides a versatile platform for the preparation of SA-M catalysts for various applications by merely altering the metal precursors.

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Comparative Proteomics Implicates a Role for Multiple Secretion Systems in Electrode-Respiring Geobacter sulfurreducens Biofilms

Cited by 10 publications

References 62 publications

Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

Meta-proteomic analysis of protein expression distinctive to electricity-generating biofilm communities in air-cathode microbial fuel cells

Harnessing the Extracellular Electron Transfer Capability of Geobacter sulfurreducens for Ambient Synthesis of Stable Bifunctional Single‐Atom Electrocatalyst for Water Splitting

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