Supplementary Material Inverse regulatory coordination of motility and adhesion in Escherichia coli

Bacterial strains and growth conditions All strains used in this study are derivatives of the E.coli K-12 strains W3110 (Hayashi et al. 2006) or MC4100 (Casadaban 1976). While curli production is similar in the two strains, only W3110 is motile, but MC4100 is non-motile as it carries an insertion of a T between nucleotide 123 and 124 in flhD (an allele previously termed flbB5301; Fig. S1). Mutations were introduced by P1 transduction (Miller 1972). All strains used in this study also carry a Δlac deletion. The following mutations were described previously: rpoS359::Tn10 (Lange and Hengge-Aronis 1991); ydaM::cat, yciR::kan, yedQ::cat, mlrA::kan, csgD::cat (Weber et al. 2006); fliA::cat (Barembruch and Hengge 2007); crl::cat (Typas et al. 2007); and clpP1::cat (Maurizi et al. 1990). The newly constructed mutant alleles yegE::kan, yeaJ:kan, yhjH::cat, ycgR::kan, flhDC::kan, fliZ::kan and rsd::cat are all deletion-insertion mutations generated by one-step inactivation according to (Datsenko and Wanner 2000) using the primers listed in Table S2. Non-polar in-frame-deletion mutations were obtained by flipping out the insertion cassettes as described (Datsenko and Wanner 2000). Cells were grown at 28°C under aeration if not otherwise indicated (as this is the appropriate temperature for curli expression). The medium used was Luria–Bertani broth (LB) (Miller 1972). Antibiotics were added as recommended (Miller 1972). For induction of proteins from the tac promoter, 10 μM IPTG was added. Growth was monitored by measuring the optical density at 578 nm (OD578).