Fig. 4.
Sups of attenuated and mutant Bacillus anthracis strains demonstrate different levels of cholesterol-dependent toxicity. (a) Sups of the Sterne 34F2 and dSterne strains were preincubated with the indicated concentrations of cholesterol or CD-cholesterol for 30 min and tested for toxicity. MbCD served as a control to demonstrate the absence of its effect on the activity of CD-cholesterol. The X axis indicates concentrations of added cholesterol, CD-cholesterol, and MbCD. (b) Sups of the indicated B. anthracis strains were preincubated with CD-cholesterol (3 μg mL−1) for 30 min and tested for toxicity with Alamar Blue as described in Materials and methods. Error bars represent 95% confidence interval of mean.