The structure and chemical composition of the nematode cuticle. Observations on some oxyurids andAscaris

Studies of the cuticle ofAspiculuris tetrapterawith both the light and the electron microscopes have shown that there are three basic layers, namely the cortex, which consists of an outer and an inner layer, the matrix layer and the fibre layer; the latter is made up of three layers. There is, in addition, a thin osmiophilic superficial membrane on the surface of the cuticle; this membrane is seen only with the electron microscope. It is shown that the major structural protein of the cuticle, although showing no axial periodicity, is collagen; the collagen is associated with hyaluronic-acid- and chondroitin-sulphate-containing mucopolysaccharides. Evidence is presented for the existence of two centres of protein synthesis (collagen fibrogenesis) in the cuticle ofA. tetraptera, Syphacia obvelataandAscaris lumbricoides.These centres are located in the inner cortex and the hypodermis. The cuticle is thus very active metabolically. I wish to acknowledge with thanks the facilities afforded me at the Molteno Institute during the course of these studies by the Director, Dr P. Tate. My thanks are also due to Dr D. L. Lee for his encouragement and helpful discussions during the investigations.