Annulment of aziridine (apholate)-induced growth inhibition in the estuarine flagellate Tetraselmis subcordiformis by some purines and pyrimidines.

Abstract

SYNOPSIS. At 850 ppm apholate [2,2,4,4,6,6‐hexakis (1‐aziridinyl)‐2,2,4,4,6,6‐hexahydro‐1,3,5,2,4,6‐triazatriphosphorine], an insect chemosterilant, reduced growth of the marine flagellate Tetraselmis subcordiformis by 50% in 21 days. Mean cell volume more sensitively indicated cellular response at low apholate concentrations than cell number or biomass. Two other aziridinyl chemosterilants tested were 12 and 120 X more toxic than apholate—values agreeing with those reported for some estuarine animals. Apholate acted directly upon the organisms rather than indirectly on the experimental medium since comparatively small molar additions of orotic acid, adenine, guanine, and thymine to apholate‐poisoned cultures annulled the growth inhibition. Determining the mode of action of aziridinyl chemosterilants by activity annulment is discussed.