Science Advances

Supplementary Materials

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  • Supplementary Methods
  • fig. S1. Isolation of IM and OM fractions from lactate-starved and lactate-sufficient D. ferrophilus IS5 cells.
  • fig. S2. UV-vis absorption spectra of extracted OM fractions from lactate-starved and lactate-sufficient D. ferrophilus IS5 cells.
  • fig. S3. Cell growth of D. ferrophilus IS5 on lactate or ITO electrode as the sole electron donor.
  • fig. S4. Differential pulse voltammograms measured with sterile medium (black), H2-consuming D. vacuolatum (pink), lactate-sufficient D. ferrophilus IS5 (blue), and lactate-starved D. ferrophilus IS5 (red).
  • fig. S5. Scanning electron microscopy images of electrode surface covered by lactate-starved D. ferrophilus IS5.
  • fig. S6. Transmission electron microscopy observation of thin sections of lactate-starved and lactate-sufficient D. ferrophilus IS5 cells treated by cytochrome-reactive DAB-H2O2 staining.
  • fig. S7. Comparison of relative cytochrome concentration in the membrane region of D. ferrophilus IS5 under lactate-starved and lactate-sufficient conditions, S. oneidensis MR-1 under electron acceptor (fumarate)-starved conditions, and G. sulfurreducens PCA grown under suboptimal temperature, 24°C.
  • fig. S8. Transmission electron microscopy observation of thin sections of S. oneidensis MR-1, G. sulfurreducens PCA, and E. coli cells treated by cytochrome-reactive DAB-H2O2 staining.
  • fig. S9. Line profiles of membrane regions of lactate-starved and lactate-sufficient D. ferrophilus IS5, S. oneidensis MR-1, and G. sulfurreducens PCA treated by positive DAB-H2O2 cytochrome staining method.
  • fig. S10. Microscopy images of lactate-starved D. ferrophilus IS5 in bright-field (left) and fluorescent modes (right).
  • fig. S11. Transmission electron microscopy observation of membrane vesicles produced by lactate-starved D. ferrophilus IS5 cells.
  • fig. S12. Schematic model of extracellular electron uptake of D. ferrophilus IS5, which is composed of multi-heme cytochromes localized at the cell OM and the surface of nanowire structures.
  • table S1. General features of the D. ferrophilus IS5 genome.
  • table S2. Genes encoding cytochrome proteins with four or more heme-binding motifs identified in the genome of D. ferrophilus IS5.
  • table S3. Comparison of the PilA gene of G. sulfurreducens PCA with the gene DFE_1992, which encodes the sole extracellular pseudopilin in the genome of D. ferrophilus IS5.
  • table S4. Potential gene clusters encoding OMC complex including two β-propeller proteins (without heme-binding sites) in the genome of D. ferrophilus IS5.
  • table S5. Electron donor (lactate) and acceptor (sulfate) concentrations contained in the IS5 cell cultures under lactate-starved and lactate-sufficient conditions.
  • table S6. Distribution of NHL-repeat β-propeller proteins identified in the gene clusters encoding OMCs of D. ferrophilus IS5 in the genomes of OSS-respiring bacteria which shared extracellular cytochromes homologous to strain IS5.

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