Fig. 6.

Anabolic activity pattern of G. sulfurreducens biofilms does not change after growth is maintained for 2 wk. (A) Electron microscopy and nanoSIMS analysis of a representative 2-wk-old biofilm. Scanning electron microscopy image showing a 2-wk-old biofilm grown at +240 mV, demonstrating the thickness of the biofilm and regions of cell lysis in the upper layers. Representative nanoSIMS images were taken in regions 1 to 4. (B) The ¹⁴N¹²C⁻ ion image is shown along with the ¹⁵N fractional abundance for each region next to their enlarged SEM image. (C) Anabolic activity patterns in 2-wk-old G. sulfurreducens biofilms. Dark blue, light blue, light green, and dark green represent the ¹⁵N fractional abundance for analyses of regions 1, 2, 3, and 4, respectively. Data are representative of 3 biological replicates. Acquisition regions are 30-μm-square and serve as scale bars.