Figure 4

Analysis of cholesterol metabolite by HPLC. R. equi USA-18ΔB8 was cultivated in medium including 0.2% cholesterol and 0.2% Tween 20 at 37°C, 200 rpm. The broth, harvested at the indicated time, was extracted with ethyl acetate and the compounds within were analyzed by HPLC using a reverse-phase column as described in Materials and methods.