FIGURE 3.

Purification schemes of HF-PS components. Two distinct components were separated using two different procedures. A, Ch HF-PS and Ne HF-PS were purified from total HF-PS by either mild acid hydrolysis or anion exchange chromatography. B, anion exchange chromatography separated a charged retained fraction (Ch HF-PS) from a neutral non-retained fraction (Ne HF-PS). C, mild acid hydrolysis followed by ethanol precipitation generated an acid labile fraction from an acid stable fraction, which subsequent structural analysis identified as Ch HF-PS and Ne HF-PS, respectively. The efficiency of acid hydrolysis was monitored along the hydrolysis steps (C). All purified fractions, as well as total HF-PS and intact B. cereus cells were analyzed by different combinations of analytical methods. *, contaminant non-carbohydrate signal.