Schistosoma mansoni: the effect of thiosinamine in vivo and in vitro.

It has been found that treatment of mice infected with Schistosoma mansoni with thiosinamine for five days had a significant effect on the formation of normal egg-shells within the ootype of female worms. The protein material, not organized into complete egg-shells, was nevertheless tanned and the surface of these amorphous masses was formed into microspines. Normal egg-shell formation was restored following drug withdrawal. The process of egg-shell formation consists of the integration of the physical moulding of egg-shell precursors derived from the vitelline cells, associated with the chemical process of protein tanning. It is suggested that thiosinamine treatment in vivo results in disruption of egg-shell formation by causing a breakdown in the moulding process and not by the inhibition of protein tanning involving the enzyme polyphenoloxidase. Treatment of worms with the drug under in vitro conditions resulted in a more enhanced effect of egg-shell formation.