Dissimilatory Fe(III) and Mn(IV) reduction.

Lovley, Derek R.

doi:10.1128/mmbr.55.2.259-287.1991

Cited by 1,200 publications

(760 citation statements)

References 238 publications

(619 reference statements)

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“…The abundance of c-type cytochromes in G. sulfurreducens, coupled with the low level of fluorescence background from other cellular material at the selected excitation and emission wavelengths, makes it possible to detect reduced cytochromes in individual cells with a fluorescent microscope or within cells in a biofilm with fibre optics. There may be practical applications for this approach, not only in the analysis of Geobacter populations in environments, such as the subsurface or on energy-harvesting electrodes, in which they are abundant (Lovley et al, 2004;Lovley, 2006), but also for other microbes that have high contents of c-type cytochromes.…”

Section: Discussionmentioning

confidence: 99%

“…Although planktonic Geobacter species in the subsurface may move with the advective groundwater flow, it has also been proposed that chemotaxis towards iron associated with flagellar-driven motility is an important mechanism for Geobacter species to locate new sources of Fe(III) oxide (Childers et al, 2002;Lovley et al, 2004). These flagellar motors are generally powered by protons moving down an electrochemical gradient (Berg, 2003;Oster and Wang, 2003).…”

Section: Discussionmentioning

confidence: 99%

“…data). This appears to be an adaptation to the fact that Fe(III) oxides are heterogenously dispersed in subsurface sediments and thus once Geobacter species deplete Fe(III) oxides within one microsite of a subsurface sediment, they must search for another source of electron acceptor (Childers et al, 2002;Lovley et al, 2004). If so, this raises the question of how Geobacter species obtain energy for maintenance and motility when they are not in direct contact with Fe(III) oxides.…”

Section: Introductionmentioning

confidence: 99%

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Fluorescent properties of c‐type cytochromes reveal their potential role as an extracytoplasmic electron sink in Geobacter sulfurreducens

Esteve‐Núñez

Sosnik

Visconti

et al. 2007

Environmental Microbiology

213

166

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A novel fluorescence technique for monitoring the redox status of c-type cytochromes in Geobacter sulfurreducens was developed in order to evaluate the capacity of these extracytoplasmic cytochromes to store electrons during periods in which an external electron acceptor is not available. When intact cells in which the cytochromes were in a reduced state were excited at a wavelength of 350 nm, they fluoresced with maxima at 402 and 437 nm. Oxidation of the cytochromes resulted in a loss of fluorescence. This method was much more sensitive than the traditional approach of detecting c-type cytochromes via visible light absorbance. Furthermore, fluorescence of reduced cytochromes in individual cells could be detected via fluorescence microscopy, and the cytochromes in a G. sulfurreducens biofilm, remotely excited with an optical fibre, could be detected at distances as far as 5 cm. Fluorescence analysis of cytochrome oxidation and reduction of the external electron acceptor, anthraquinone-2,6-disulfonate, suggested that the extracytoplasmic cytochromes of G. sulfurreducens could store approximately 10(7) electrons per cell. Independent analysis of the haem content of the cells determined from analysis of incorporation of (55)Fe into cytochromes provided a similar estimate of cytochrome electron-storage capacity. This electron-storage capacity could, in the absence of an external electron acceptor, permit continued electron transfer across the inner membrane sufficient to supply the maintenance energy requirements for G. sulfurreducens for up to 8 min or enough proton motive force to power flagella motors for G. sulfurreducens motility. The fluorescence approach described here provides a sensitive method for evaluating the redox status of Geobacter species in culture and/or its environments. Furthermore, these results suggest that the periplasmic and outer-membrane cytochromes of Geobacter species act as capacitors, allowing continued electron transport, and thus viability and motility, for Geobacter species as they move between heterogeneously dispersed Fe(III) oxides during growth in the subsurface.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fluorescent properties of c‐type cytochromes reveal their potential role as an extracytoplasmic electron sink in Geobacter sulfurreducens

Esteve‐Núñez

Sosnik

Visconti

et al. 2007

Environmental Microbiology

213

166

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“…The annotated genomic sequence (Heidelberg et al, 2002) of S. oneidensis MR-1 revealed numerous genes predicted to encode putative redox proteins including cytochromes, hydrogenases, flavins, ferredoxins and Fe-S proteins. Genome comparisons with other sequenced dissimilatory metal-reducing bacteria (DMRB) such as Geobacter sulfurreducens, G. metallireducens (Lovley et al, 2004) and Anaeromyxobacter dehalogenans reveal that these organisms share a remarkable wealth of genes that encode one particular type of electron transfer protein, the multihaem c-type cytochrome. While the organisms display no significant sequence homology, the abundance of c-type cytochromes appears to be a common characteristic of DMRB and is likely linked to their considerable flexibility in electron acceptor utilization.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenase‐ and outer membrane c‐type cytochrome‐facilitated reduction of technetium(VII) by Shewanella oneidensis MR‐1

Marshall¹,

Plymale²,

Kennedy³

et al. 2007

Environmental Microbiology

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Pertechnetate, (99)Tc(VII)O(4)(-), is a highly mobile radionuclide contaminant at US Department of Energy sites that can be enzymatically reduced by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble Tc(IV)O(2(s)). In other microorganisms, Tc(VII)O(4)(-) reduction is generally considered to be catalysed by hydrogenase. Here, we provide evidence that although the NiFe hydrogenase of MR-1 was involved in the H(2)-driven reduction of Tc(VII)O(4)(-)[presumably through a direct coupling of H(2) oxidation and Tc(VII) reduction], the deletion of both hydrogenase genes did not completely eliminate the ability of MR-1 to reduce Tc(VII). With lactate as the electron donor, mutants lacking the outer membrane c-type cytochromes MtrC and OmcA or the proteins required for the maturation of c-type cytochromes were defective in reducing Tc(VII) to nanoparticulate TcO(2) x nH(2)O((s)) relative to MR-1 or a NiFe hydrogenase mutant. In addition, reduced MtrC and OmcA were oxidized by Tc(VII)O(4)(-), confirming the capacity for direct electron transfer from these OMCs to TcO(4)(-). c-Type cytochrome-catalysed Tc(VII) reduction could be a potentially important mechanism in environments where organic electron donor concentrations are sufficient to allow this reaction to dominate.

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“…Past, present, and future" (Galloway et al, 2004) and "Dissimilatory Fe (III) and Mn (IV) reduction" (Lovley, 1991) as well as classic articles entitled "Northern peatlands: Role in the carbon cycle and probable responses to climatic warming" (Gorham, 1991) and "Fragmentation and flow regulation of the world's large river systems" (Nilsson, Reidy, Dynesius, & Revenga, 2005).…”

Section: Considered Abstract Contained Abstractmentioning

confidence: 99%

Rebuttal to Peng et al. (2019). “Characteristics and development trends of ecohydrology in lakes and reservoirs: Insights from bibliometrics”. Ecohydrology, 12(3), article number: UNSP e2080

2019

Ecohydrology

View full text Add to dashboard Cite

Dissimilatory Fe(III) and Mn(IV) reduction.

Cited by 1,200 publications

References 238 publications

Fluorescent properties of c‐type cytochromes reveal their potential role as an extracytoplasmic electron sink in Geobacter sulfurreducens

Fluorescent properties of c‐type cytochromes reveal their potential role as an extracytoplasmic electron sink in Geobacter sulfurreducens

Hydrogenase‐ and outer membrane c‐type cytochrome‐facilitated reduction of technetium(VII) by Shewanella oneidensis MR‐1

Rebuttal to Peng et al. (2019). “Characteristics and development trends of ecohydrology in lakes and reservoirs: Insights from bibliometrics”. Ecohydrology, 12(3), article number: UNSP e2080

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