FIGURE 5.

A possible signal transduction required for resistance to protamine. A, percentage survival and cfu in log₁₀ (inlet) of wild-type and ΔaroK mutant (Keio) after incubation with protamine (0 or 1.0 mg/ml). Percentage survival was calculated by comparing cfu from plates with protamine to that from input (the column in black). B, -fold change of percentage survival of wild-type and ΔcpxR mutant (Keio) after incubation in the presence of protamine (1.0 mg/ml) supplemented with indole (2 mm) or without. -Fold change was calculated as follows: percentage survival of the strains with indole divided by that without. C, -fold change in β-galactosidase activity of wild-type harboring pYS1736 and strains carrying chromosomal lacZ fusions at degP (PND2000), cpxP (SP1), and mgrB (MG1301) grown in LB for 4 h supplemented with or without 2 mm indole or solvent dimethyl sulfoxide (DMSO). -Fold change was calculated as follows: β-galactosidase activity of strains with indole or DMSO divided by that without. D, AroK is a kinase that mediates biosynthesis of chorismate, a precursor for the synthesis of aromatic metabolites including anthranilate, salicylate, 2,3-dihydroxybenzoate as well as indole (the structure in red).