Curli production as judged from the major subunit CsgA production of WT Rv and LT2 and their derivatives. Curli production is shown for WT Rv and its ddhC::Tn5 (A1-8) and waaG::Tn5 (A1-9) mutants after 2, 4, and 6 days of growth (A) and for WT LT2 with its ΔwaaG::kan (YA155) derivative and the waaG-complemented strain of YA155 (YA156) (B) after 2 and 4 days of growth on LB at 25°C. Strains S. enterica serovar Typhimurium LT2 YA151 (ΔcsgA) and S. enterica serovar Enteritidis 4b (SE) were included as negative and positive controls, respectively, in panel A. Curli protein was isolated by formic acid treatment of whole-cell lysates, separated by SDS-PAGE, and probed with anti-S. enterica serovar Enteritidis 4b AgfA monoclonal antibodies.