Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms

Gorby et al. 10.1073/pnas.0604517103.

Supporting Figures

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Supporting Figure 5
Supporting Figure 6
Supporting Figure 7
Supporting Figure 8

Fig. 5. Effect of electron acceptor availability on nanowire production. (A) Scanning electron microscopy (SEM) image of wild-type strain Shewanella oneidensis MR-1 taken from electron-acceptor-limited chemostat operating at low agitation (50 rpm). (B) SEM image of wild-type strain S. oneidensis MR-1 taken from chemostat operating with the excess of electron acceptor (20% dissolved O₂ tension).

Supporting Figure 6

Fig. 6. Scanning tunneling microscopy (STM) image of the frayed end of bundled filaments showing individual strands.

Supporting Figure 7

Fig. 7. Reductive transformation of solid=phase iron oxide by bacterial nanowires. (A) Transmission electron microscopy (TEM) images of whole mounts of S. oneidensis MR-1 cells incubated with aqueous suspension of Si-HFO. The extracellular features were consistent with the dimensions of nanowires where the nanocrystalline magnetite was the major component of the biomineralized Si-HFO (indicated by arrows). (B) TEM image of a thin section revealing linear arrays of reduced iron minerals in a ground mass of ferrihydrite solidified in an agar growth medium. These thin sections were from samples taken nearly 3 cm from the top of the medium where the cells were applied. No cells were detected in the region where these iron-bearing structures were observed. These data suggest that redox-reactive nanowires are able to transform solid-phase iron oxides at considerable distances from bacterial cells.

Supporting Figure 8

Fig. 8. Nanowires produced by GSPD (A) and DMTRC/OMCA (B) mutants were morphologically similar to those produced by wild-type cell but were poorly conductive based on STM, as demonstrated here for the GSPD mutant (C).