Figure 1

Cell aggregation and biofilm formation of S. oneidensis MR-1 wild type and mutants. (A) Cell aggregation and biofilm formation of S. oneidensis MR-1 wild type and mutants in planktonic culture under minimal medium conditions. See Materials and Methods for details. Note the thick biofilm ring in the wild type culture at the top (top arrow) and aggregated cells on the bottom of the tube (lower arrow). (B) Quantification of cell aggregation in S. oneidensis MR-1 wild type and mutants in planktonic culture under minimal medium conditions. The ratio of the optical density measured at 600 nm of wild type and mutant cultures after and before dispersion was used to determine their aggregation phenotypes.