FIGURE 4.

Role of ROS in the synergistic killing of kanamycin with alanine. (A) Hydroxyl radical was quantified in EIB202 in the presence of kanamycin, alanine and/or glucose as indicated by colorimetric method (left panel) and by fluorescence (right panel). (B) Percent survival of EIB202 in the presence of thiourea (160 mM), alanine (40 mM) or both. (C) Percent survival of EIB202 in the presence or absence of thiourea (160 mM) and the indicated concentration of alanine. (D) Percent survival of EIB202 in the presence or absence of alanine and the indicated concentration of thiourea (160 mM). (E) Percent survival of EIB202 in the presence or absence of kanamycin (40 μg/mL), thiourea (160 mM) and alanine (40 mM) at the indicated time point. (F) Percent survival of EIB202 in the presence or absence of alanine and the indicated concentration of Fe³⁺(C₆H₁₀FeNO₈). (G) Effect of malonate (20 mM) on hydroxyl radical concentration in the presence or absence of alanine and/or kanamycin by two different assays as by colorimetric method (left panel) and fluorescence (right panel). ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001 as determined by Student’s t-test.