FIG 2.
Model for electron and proton flux in Methanosarcina acetivorans during direct interspecies electron transfer (DIET) with Geobacter metallireducens. Ethanol is provided as the source of electrons, and the electron-donating partner (G. metallireducens) transfers those electrons to the electron-accepting partner (M. acetivorans) for carbon dioxide reduction to CH4 through the proposed pathways shown. The degree of increased transcript abundance for subunits of the protein complexes is provided. See the text for a more detailed explanation.