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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)

A new 'family' of possible cross-linking groups from hinge ligaments of lamellibranchs were isolated and identified. The main members are 3,3'-methylene-bistyrosine, 3,3'-methylene-bis-dopa but there are also chlorinated compounds the origins of which are being investigated. The deposition of resilin and chitin were studied cytologically and three types of secretory granules were identified in the electron microscope but their chemical composition and identification awaits high resolution autoradiography now in progress. The work on the time course of incorporation of tyrosine was concluded. The optical properties of chitin were investigated and the results obtained so far indicate that the anomalous dispersion and interference colours are caused by a superstructure not hitherto taken into account. The birefringence and stability of cytoplasmic microtubules were studied quantitatively. It looks as if the birefringence of the spindle apparatus may be caused by the form birefringence of arrays of such tubules. (Author)