Fig. 3

Survival curves of S. pneumoniae strains in the presence and absence of the Natto peptide. a S. pneumoniae R6 cells were pre-cultured to a cell density of approximately 10⁷ cells/mL in TH broth containing 5% (v/v) horse hemolysate. The Natto peptide was then added at a concentration of 64 μg/mL. b, c S. pneumoniae R6 (b) and P103 (lytA-deficient mutant derived from R6) (c) cells were suspended at a density of approximately 10⁵ cells/mL in TH broth containing 5% (v/v) horse hemolysate. The Natto peptide was then added at a concentration of 64 μg/mL. Throughout the cultivation, the cultures were sampled, and culture aliquots were spread on a TH agar supplemented with 5% (v/v) horse hemolysate, and cultured for 24 h. Grown colonies were then counted. Dashed lines indicate cell numbers in the presence of the Natto peptide. Solid lines indicate cell numbers in the absence of the Natto peptide. Each experiment performed at least three times, and the representative results are presented. The similar results were observed in the same experiments