Cytochemical studies on the cuticle and epidermis of Tubifex tubifex Müll. with special regard to the localization of polysaccharides, heavy metals and the DAB-reactivity.

The cuticle consits of collagenous fibres and of two types of mucopolysaccharides. The whole cuticle contain PAS-positive polysaccharides, but the acid ones are localized only in the surface zone, both in the epicuticle and in the supracuticular mucoid coat. On the surface-damaged region of the cuticle bacterial infection was observed, those intact mucoid coat may be essential in protection against bacterial infection. Microvilli of the supporting cells play significant role in repairing of cuticular injuries. Acid mucopolysaccharides of the cuticle and epidermis may function as traps for heavy metals, proved by their significant heavy metal content. The cytosol of the epidermal cells possess considerable DAB-reactivity. The enzyme, responsible for the DAB-reaction, may be transported by the microvilli towards the cuticular surface and can play central role in the detoxication of organic foreign compounds.