Immunohistochemical localization of endogenous Bsc -PYP-1 in B. schroederi female adult worms. Worms were fixed in paraformaldehyde and embedded in paraffin as described in Materials and Methods. The sections (6-μm thickness) were incubated with either mouse anti-rBsc-PYP-1 serum at 1:100 (A) or pre-immune serum at 1:100 (B) diluted in PBS. (C) and (D) (both 20×) are magnified areas of (A) and (B) (both 10×), respectively. Arrows indicate antibody-labeled regions. Abbreviations: Mu, muscle; Cu, cuticle; Lc, lateral chord; Hd, hypodermis; Ov, ovary; Gu, gut; Gue, gut epithelium; Ut, uterus; Nee, non-embryonated eggs.