Fig 3.

Release of uric acid and xanthine oxidase activity into intestinal loop fluids and serum after infection of rabbits with EPEC E22 or rabbit STEC E22-stx2. (A) Comparison of the uric acid contents of uninfected and EPEC E22-infected ligated rabbit intestinal loops after a 20-h infection. Each line segment represents the uric acid from an uninfected and an infected intestinal loop fluid from the same animal. (B) Increase in serum uric acid in non-surgically altered rabbits infected orally with strain E22 for 7 days compared with levels in the same animal preinfection. (C) Detection of xanthine oxidase (XO) activity in intestinal loop fluids from infected, but not uninfected, ligated ileal loops. XO activity of 6 pairs of intestinal loop fluid samples from 6 rabbits. Uninfected and infected loops shown in adjacent bars as pairs of loop fluids are from the same animal. The first 3 pairs on the left show data from experiments in which some loops were infected with EPEC E22, and the pairs on the right side are from 3 animals for which some loops were infected with STEC E22-stx2. Although asterisks are omitted, in each case, the XO activity was significantly higher in the infected loop than in the uninfected loop fluid. In 5 of 6 cases, the uninfected loop fluid XO activity was a negative number, i.e., uric acid was not generated but instead disappeared in the uninfected loop fluids during the assay, presumably due to uricase activity.