Fig 2.

Biofilm images of the 1291 wild-type strain (A) and the Ng-ntrX isogenic mutant strain (B) using green fluorescent protein to show LIVE/DEAD cells. Wild-type biofilms contain predominantly live cells, as evidenced by the large amount of GFP produced. Ng-ntrX cells in contrast, contain predominantly dead cells, indicating the genes regulated by NtrX are important in the formation of a live, functional biofilm. Images were taken as 1-dimensional (1D) slices at ×200 magnification and stacked to produce a 3D image using Volocity software.