Protective Role of
            <i>tolC</i>
            in Efflux of the Electron Shuttle Anthraquinone-2,6-Disulfonate

Ôta, Yôko; Lies, Douglas P.; Newman, Dianne K.

doi:10.1128/jb.184.6.1806-1810.2002

Cited by 89 publications

(72 citation statements)

References 42 publications

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“…AQDS enhanced GO reduction to a greater degree than riboflavin, suggesting that it reacts more quickly with GO. This observation is in contrast to the behavior of these electron shuttles in iron(III) oxide reduction (5,19). The significant acceleration of GO reduction in the presence of AQDS may have biotechnological implications for microbial graphene production.…”

contrasting

confidence: 52%

“…Two paralogs of MtrC, encoded by omcA and mtrF, can compensate for the loss of MtrC to reduce a variety of substrates (3,6). The activity of the Mtr respiratory pathway on insoluble substrates is accelerated by electron shuttles (5,19), either produced in situ by MR-1 (the riboflavin and flavin mononucleotide flavins) (13,20) or added exogenously to cultures such as 9,10-anthraquinone-2,6-disulfonic acid (AQDS) (5).…”

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confidence: 99%

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Deciphering the Electron Transport Pathway for Graphene Oxide Reduction by Shewanella oneidensis MR-1

Jiao

Qian

et al. 2011

J Bacteriol

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confidence: 52%

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confidence: 99%

Deciphering the Electron Transport Pathway for Graphene Oxide Reduction by Shewanella oneidensis MR-1

Jiao

Qian

et al. 2011

J Bacteriol

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“…While the substrate specificity of this particular transporter system is unknown, homologous efflux pumps, including the S. oneidensis MR-1 TolC system (44), have been described in several gram-negative organisms where they play a role in export of and resistance to multiple antimicrobial agents, heavy metals, and organic solvents (37). In particular, the observation that TolC-dependent efflux system of MR-1 is required for protection against toxic levels of AQDS and other redox active compounds may provide direct evidence linking efflux pumps with the reduction of insoluble electron acceptors (44).…”

Section: Resultsmentioning

confidence: 99%

Global Transcriptome Analysis of Shewanella oneidensis MR-1 Exposed to Different Terminal Electron Acceptors

et al. 2005

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To gain insight into the complex structure of the energy-generating networks in the dissimilatory metal reducer Shewanella oneidensis MR-1, global mRNA patterns were examined in cells exposed to a wide range of metal and non-metal electron acceptors. Gene expression patterns were similar irrespective of which metal ion was used as electron acceptor, with 60% of the differentially expressed genes showing similar induction or repression relative to fumarate-respiring conditions. Several groups of genes exhibited elevated expression levels in the presence of metals, including those encoding putative multidrug efflux transporters, detoxification proteins, extracytoplasmic sigma factors and PAS-domain regulators. Only one of the 42 predicted c-type cytochromes in MR-1, SO3300, displayed significantly elevated transcript levels across all metal-reducing conditions. Genes encoding decaheme cytochromes MtrC and MtrA that were previously linked to the reduction of different forms of Fe(III) and Mn(IV), exhibited only slight decreases in relative mRNA abundances under metal-reducing conditions. In contrast, specific transcriptome responses were displayed to individual non-metal electron acceptors resulting in the identification of unique groups of nitrate-, thiosulfate-and TMAO-induced genes including previously uncharacterized multi-cytochrome gene clusters. Collectively, the gene expression results reflect the fundamental differences between metal and non-metal respiratory pathways of S. oneidensis MR-1, where the coordinate induction of detoxification and stress response genes play a key role in adaptation of this organism under metal-reducing conditions. Moreover, the relative paucity and/or the constitutive nature of genes involved in electron transfer to metals is likely due to the low-specificity and the opportunistic nature of the metal-reducing electron transport pathways.Metal ion reducing microbes play a central role in the biogeochemical cycling of key elements by coupling the reduction of insoluble metal oxides to the oxidation of the organic carbon. Microbial metal reduction has been identified as an effective means for immobilizing heavy metals and radionuclides in situ thus preventing their migration in the environment. Among metal ion reducing bacteria, Shewanella oneidensis MR-1 is notable due to its extensive respiratory versatility. In addition to O 2 , this bacterium can respire various organic and inorganic substrates, including fumarate, nitrate, nitrite, thiosulfate, elemental sulfur, trimethylamine N-oxide (TMAO), dimethyl sulfoxide (DMSO), anthraquinone-2,6-disulphonate (AQDS), as well as various soluble and solid metal electron acceptors such as chromium, cobalt, iron, manganese, technetium, uranium, and vanadium (12,27,34).Analysis of the S. oneidensis MR-1 genome sequence predicts a branched electron transport system that contains 42 putative c-type cytochromes and supports the proposed complexity of the energy-generating pathways in this organism (20, 30) Gene expression and environmental sen...

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“…Genes disrupted by transposons were identified as described in ref. 42 and PCR verified. Directed mutagenesis was carried out as described in ref.…”

Section: Discussionmentioning

confidence: 99%

Extracellular respiration of dimethyl sulfoxide by Shewanella oneidensis strain MR-1

Gralnick

Vali

Lies

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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198

209

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Shewanella species are renowned for their respiratory versatility, including their ability to respire poorly soluble substrates by using enzymatic machinery that is localized to the outside of the cell. The ability to engage in ''extracellular respiration'' to date has focused primarily on respiration of minerals. Here, we identify two gene clusters in Shewanella oneidensis strain MR-1 that each contain homologs of genes required for metal reduction and genes that are predicted to encode dimethyl sulfoxide (DMSO) reductase subunits. Molecular and genetic analyses of these clusters indicate that one (SO1427-SO1432) is required for anaerobic respiration of DMSO. We show that DMSO respiration is an extracellular respiratory process through the analysis of mutants defective in type II secretion, which is required for transporting proteins to the outer membrane in Shewanella. Moreover, immunogold labeling of DMSO reductase subunits reveals that they reside on the outer leaflet of the outer membrane under anaerobic conditions. The extracellular localization of the DMSO reductase in S. oneidensis suggests these organisms may perceive DMSO in the environment as an insoluble compound.DMSO ͉ metabolism ͉ cold temperature adaptation

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Protective Role of tolC in Efflux of the Electron Shuttle Anthraquinone-2,6-Disulfonate

Cited by 89 publications

References 42 publications

Deciphering the Electron Transport Pathway for Graphene Oxide Reduction by Shewanella oneidensis MR-1

Deciphering the Electron Transport Pathway for Graphene Oxide Reduction by Shewanella oneidensis MR-1

Global Transcriptome Analysis of Shewanella oneidensis MR-1 Exposed to Different Terminal Electron Acceptors

Extracellular respiration of dimethyl sulfoxide by Shewanella oneidensis strain MR-1

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