PROPERTIES OF RESILIN AND ELASTOMERS IN INSECTS.

The biosynthesis of insect rubber-like cuticle was studied by means of autoradiography and electron microscopy, and the structure and development of insect hard cuticle was studied by different types of microscopy and solvent extractability. The results obtained indicate that the insect cuticle together with the epidermal cells constitute a very complex morphogenetic system, where the properties of the final product are very precisely controlled. Proteins can be present both in a crosslinked and an uncross-linked state. Two protein-bound diphenolic compounds have been isolated from hard cuticle, one of them has been identified as arterenone. They may be involved in cross-linking the proteins. Bifunctional amino acids were isolated from a rubber-like protein in molluscs. Measurements of the work and heat changes going on during deformation of elastin indicate that this protein is not rubber-like, but that the elasticity can be due to interaction between hydrophobic groups in the protein and the surrounding matter. Better methods were worked out for the isolation of the spindle apparatus from dividing cells. (Author)