General Phenotype of NADase Induction by CLI Treatment in Streptococcus pyogenes

Figure 4

Extracellular NADase activity in emm6, emm28, or emm89 strains cultured with CLI. NADase activity was determined based on the criteria described in Figure 1. The OD₆₆₀ of overnight culture with CLI (2⁻⁹ to 2⁻⁴ μg/ml) is shown by a percentage (%) of that without CLI (0 μg/ml). The maximum CLI concentration that did not suppress the bacterial growth to less than 50% of that without CLI is shown in red, which was 2⁻⁷ μg/ml in strain NU-syoni, 2⁻⁶ μg/ml in strains ncu28A and Seibu, 2⁻⁷ μg/ml in strain ncu52 A, 2⁻⁶ μg/ml in strain ncu60 A, 2⁻⁵ μg/ml in strain ncu61A, respectively. At least three independent experiments were performed. Error bars indicate the standard errors of the means. Significant increases in extracellular NADase activity by CLI treatment when compared with that without CLI treatment, which is shown by the black bar, are marked with asterisks ( using Student’s t-test).