Figure 3.

Colorized SEM images of stalk and dread biominerals of selected marine and freshwater FeOB. (A) Twisted stalk (blue) formed by a M. ferrooxydans PV-1 cell (yellow). Most Zetaproteobacteria isolates form stalks. (C) In contrast, M. aestuarium CP-5 and M. ferrinatatus CP-8 produce only short dreads (red), which are easily shed from the cell (inferred cell position indicated by dashed yellow line). (B) Stalk (blue) and dreads (red) of the freshwater Betaproteobacteria FeOB Ferriphaselus sp. R-1 resembled the structures formed by marine FeOB. Scale bars = 1 µm. Images reproduced with permission: (A) from Chan et al. (2016), (B) from Kato et al. (2015b), (C) from Chiu et al. (2017).