Positive controls for the BCA-assays, silver stains, and Western blots were made by examining NaOH-treated cyst walls that had been incubated with native Giardia CWPs or with MBP fusion-proteins containing Giardia CWP1 (lanes 2 and 3, respectively, in Figs. 3A and 3B and see below). Here, MBP is linked to cyst.