Structural and biochemical analysis of the parasite Gordius villoti (Nematomorpha, Gordiacea) cuticle.

The cuticle of the nematomorpha Gordius villoti is a proteinaceous extracel lular structure that covers the body during the endoparasitic life in the h emocoelic cavity of insect hosts, and of the free-living adult animals. The ultrastructure of the cuticle has a complex spatial organization with seve ral parallel layers of large diameter fibers, interposed thinner fibrous el ements and honeycomb-shaped matrix surrounding the fibers. When adult isola ted cuticles were partially solubilized by several compounds, the structure revealed a strong insolubility and the main fibers were always observable. HPLC and spectrophotometric assays carried out to investigate the presence of tyrosine cross-linking, indicated such a mechanism as a key-element in the hardening process of the cuticle. Such data strongly suggest that the G ordius cuticle contains dityrosine compounds, whose formation is probably m ediated by endogenous peroxidase activity. (C) 2000 Harcourt Publishers Ltd .