FIG. 4.

Biofilms and exponential-phase planktonic cells of B. cereus contain eDNA. (a) A biofilm population (lane Bf), a planktonic population (lane Pl), and a planktonic stationary-phase population from a biofilm culture flask (lane PlBf) were placed in wells of a 0.8% agarose gel, along with biofilm treated with DNase (lane D), with RNase plus DNase (lane D+R), and with proteinase K (lane P). Lane M contained HindIII-digested λ DNA. (b) Ethidium bromide-stained agarose gel containing planktonic populations from cultures that were different ages. Populations were harvested by centrifugation after they were cultured in LB broth for 2, 3, 4, 5, 6, and 24 h and normalized for cell density, and cell suspensions were loaded directly into the wells for electrophoresis. Lane M contained HindIII-digested λ DNA as a size marker.