FIGURE 9.

Effect of urate on killing of P. aeruginosa by LPO. A, hypothiocyanite was generated by the addition of 50 μm hydrogen peroxide to 10 nm LPO and 100 μm thiocyanate in the presence or absence of 250 μm urate in 10 mm phosphate buffer, pH 6.8. After a 10-min incubation at room temperature, catalase (10 μg/ml) was added to remove residual hydrogen peroxide. Bacteria (1 × 10⁵/ml) were then added and incubated for 2 h at 37 °C with gentle rotation. B, P. aeruginosa were incubated for 1 h (37 °C, 6 rpm) with 2 μg/ml glucose oxidase, 10 nm LPO, and 100 μm thiocyanate in the presence or absence of 250 μm urate in 10 mm phosphate buffer, pH 6.8, containing 1 mg/ml glucose. This system generated ∼1.5 μm hydrogen peroxide/min. Catalase (10 μg/ml) was added prior to dilution and plating. Data are means and standard errors of 3–4 separate experiments. Data were analyzed by ANOVA using Holm-S̊ídák post hoc analysis. *, p < 0.05 for comparisons versus the complete reaction system.