Transgenic worms expressing the met35cys variant of the beta-amyloid peptide show a dramatic reduction in amyloid deposits. Shown here are thioflavin S-reactive deposits (arrows) in transgenic animals expressing wild-type (upper left animal) or met35cys variant beta 1-42 (lower right animal). Adult animals from strain CL2120 (beta 1-42 wt) or strain CL3115 (beta 1-42 met35cys) were fixed, permeabilized, and stained in parallel with thioflavin S. (The blue fluorescence in the central portion of both animals is non-specific background fluorescence.)