A factorial experiment to confirm that the effect on H. bakeri is mediated by cysteine proteinase activity. The worms were incubated in the presence/absence of papaya latex, presence/absence of cysteine, and presence/absence of the specific CP inhibitor E-64. The only treatment to show accelerated loss of motility was when worms were incubated with papaya latex, in the presence of cysteine but absence of E-64. This treatment is highlighted in bold. For the full statistical analysis of these and related data, see Stepek et al. . Reprinted with permission.