Confocal Microscopy of Biofilms

Established biofilms of GFP-expressing strains JSG4093 and JSG4244 were incubated with or without 0.2% L-arabinose for 24 hr prior to imaging. Biofilms were washed two times in PBS and fixed in 2% paraformaldehyde (PFA, Affimetrix) for 1 hour at room temperature and saved for later imaging. The amount of biofilm and the structure of the biofilm can be inferred by the amount of GFP signal detected (Franklin et al., 2015). Biomass and average thickness were assessed by automated capturing of 5 random Z-stacks per well in 4 wells per treatment using a Nikon A1R Live Cell Inverted Confocal microscope. The Z-stacks were then analyzed using the software package COMSTAT2.