The Design of the Nematode Body Wall: the Ontogeny of the Cuticle.

Abstract

Hypotheses are presented which explain how the one-cell-thick nematode epidermis determines the structure of the complex proteinaceous cuticle during its ontogeny. The pseudometamerism, 3 major layers, and all radial structures, it is concluded, are laid down around the epidermis which acts as a template. The structurally very complex multilamellate, cross-fibre, and striated-paracrystalline materials can, it is demonstrated, be induced by spontaneous self-assembly on a liquid crystal model. The ontogeny of the cuticle, it is hypothesized, must involve a messenger system which induces changes in pre-set material, because the full thickness of cuticle is laid down initially as unmodified material which later switches to its final form. It is speculated that this may involve a paracrystalline switch comparable to the troponin-complex:tropomyosin-sequence of muscle contraction, because of the presence of striated-paracrystalline material and reports of nets, banded fibres, paracrystalline-like structures and possibly tactoids in some cuticles.