Effect of some benzthiazol derivatives on Euglena gracilis.

6-Substituted derivatives of 2-benzthiazolthiol and allyl (2-benzthiazolylthio)acetate exhibit, after an exposure to light, and inhibitory action on the division of dark-depigmented Euglena cells, as well as the synthesis of chlorophyll. These substances also have a marked inhibitory effect on the devlopment of plastids in nondividing cells maintained under resting conditions. No induction of heterotrophic plastid--free mutants was found under growth or resting conditions.