Fig. 8. Escapin's bactericidal effect was greatest in the enriched growth medium and L-lysine. (A,B) E. coli and (C) Staphylococcus aureus cells in early-log growth phase were cultured in M9-glucose medium (for E. coli) or LB (for S. aureus), and 4 samples of equal cell density were resuspended in different growth media in the presence of escapin (Esc: 50 µg ml^-1) or (C) buffer control. Cells were then incubated at 37°C for 60 min. Ye, 1% yeast extract; Try, 1% Tryptone Peptone; Lys, 50 mmol l^-1 L-lysine; Arg, 50 mmol l^-1 L-arginine; His, 50 mmol l^-1 L-histidine; Val, 50 mmol l^-1 L-valine; aa, amino acid mixture containing 20 L-amino acids each at 50 µmol l^-1. In a follow-up experiment, a 10 times higher concentration of Ye or aa was used, and similar results were observed. Values are means ± S.E.M., N=3. An asterisk indicates a significant reduction in the number of viable clones (P<0.05, t-test).