Abundance of the multiheme c-type cytochrome OmcB increases in outer biofilm layers of electrode-grown Geobacter sulfurreducens

Camille S. Stephen, Edward V. LaBelle, Susan L. Brantley, Daniel R. Bond

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

When Geobacter sulfurreducens utilizes an electrode as its electron acceptor, cells embed themselves in a conductive biofilm tens of microns thick. While environmental conditions such as pH or redox potential have been shown to change close to the electrode, less is known about the response of G. sulfurreducens to growth in this biofilm environment. To investigate whether respiratory protein abundance varies with distance from the electrode, antibodies against an outer membrane multiheme cytochrome (OmcB) and cytoplasmic acetate kinase (AckA) were used to determine protein localization in slices spanning ∼25 μm-thick G. sulfurreducens biofilms growing on polished electrodes poised at +0.24 V (vs. Standard Hydrogen Electrode). Slices were immunogold labeled post-fixing, imaged via transmission electron microscopy, and digitally reassembled to create continuous images allowing subcellular location and abundance per cell to be quantified across an entire biofilm. OmcB was predominantly localized on cell membranes, and 3.6-fold more OmcB was detected on cells 10-20 μm distant from the electrode surface compared to inner layers (0-10 μm). In contrast, acetate kinase remained constant throughout the biofilm, and was always associated with the cell interior. This method for detecting proteins in intact conductive biofilms supports a model where the utilization of redox proteins changes with depth.

Original languageEnglish (US)
Article numbere104336
JournalPloS one
Volume9
Issue number8
DOIs
StatePublished - Aug 1 2014

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Geobacter sulfurreducens
Geobacter
Cytochrome c Group
Biofilms
cytochromes
biofilm
electrodes
Electrodes
acetate kinase
Acetate Kinase
Oxidation-Reduction
Proteins
proteins
cells
redox potential
Cell membranes
Cytochromes
Transmission Electron Microscopy
hydrogen
transmission electron microscopy

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

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Abundance of the multiheme c-type cytochrome OmcB increases in outer biofilm layers of electrode-grown Geobacter sulfurreducens. / Stephen, Camille S.; LaBelle, Edward V.; Brantley, Susan L.; Bond, Daniel R.

In: PloS one, Vol. 9, No. 8, e104336, 01.08.2014.

Research output: Contribution to journalArticle

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