FIG 4.

Cellular uric acid degradation activity. (A) The procedure for determining uric acid degradation activity and cell growth. (B and C) Uric acid degradation activity (B) and cell growth (C) of the wild type and ΔaegA, ΔygfTS, and ΔaegA ΔygfTS mutant strains in minimal medium supplemented with uric acid as the sole nitrogen source. (D and E) Uric acid degradation activity (D) and cell growth (E) in the absence of uric acid. (F and G) Introduction of plasmid-borne aegA and ygfTS genes restores the uric acid degradation activity (F) and cell growth (G) with uric acid as the sole nitrogen source. (H and I) The amount of uric acid (H) and cell density (I) after a 24-h incubation under aerobic, microaerobic, and anaerobic conditions with uric acid as the sole nitrogen source. The cellular uric acid degradation activity was monitored by measuring the OD₂₉₁ of the culture supernatant.