Oxidative Stress Induced by Polymyxin E Is Involved in Rapid Killing of Paenibacillus polymyxa

Figure 2

ROS accumulation in P. polymyxa and oxidative stress-induced damage to cell. (a) Fluorescence signal of DCF-DA converted from DCFH-DA due to oxidation, (b) lipid peroxidation production of MDA, (c) visualization of genomic DNA fragmentation, and (d) Relative expression level of ilvD encoding for DHAD. For panels (a), (b), and (d), cells were treated with or without 1.6 × 10⁵ U/mL colistin for 2 h. The data are representative of three independent experiments. Points represent the means and bars represent the standard deviation of triplicate samples. For panel (c), lanes 1 to 6 refer to genomic DNA from P. polymyxa treated with 0, 4 × 10⁴ U/mL, 8 × 10⁴ U/mL, 1.2 × 10⁵ U/mL, 1.6 × 10⁵ U/mL, and 2.0 × 10⁵ U/mLof colistin, respectively; M represents molecular mass marker.

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