Role of the PspA and PspC in pneumococcal catecholamine responsiveness. Panels A-C show the time course of growth of pspA, pspC and pspAC mutants in serum-medium in the absence (black line) or presence of 10 μM NE (red line). Panels D-F shows the pspA (pspA
-), pspC (pspC
-) and pspAC (pspAC
-) mutant uptake of Tf-complexed Fe (in the form of 55Fe) +/- NE; note that the wildtype D39 uptake of Tf-Fe in the presence of NE is shown in Figure 2B. Values shown in panels D-F are means of triplicate counts; for all experiments, n = 3.