THE EFFECTS OF DIFFERENT HALOGENATED ALKYL AMINES ON THE DIVISION OF SEA URCHIN EGGS

¹ George Washington University Cancer Clinic and the Department of Anatomy in the School of Medicine, Washington, D. C.

1. The capacities of different mustards for blocking or delaying the cleavage of sea urchin eggs were compared by exposing the eggs of Arbacia punctulata, Tripneustes esculentus and Lytechinus variegatus to freshly prepared solutions continuously, beginning 10 to 13 minutes after fertilization.

2. At least two -halo groups are necessary to confer the highest potency of the molecule. A third -chloroethyl or a second bis-(-chloroethyl)-amine group, or a non-chlorinated substitution on the nitrogen alters the activity of the molecule. -chloropropyl or -chloropropyl can substitute for the -chloroethyl radical. Methyl bis--bromine was slightly more active than its chlorine homologue and a fluorine congener was probably less active.

3. Environmental conditions have not been standardized in these experiments to permit an evaluation of differences in susceptibility of the different species.

4. In the range of 0.065-1.040 mM methyl-bis-(-chloroethyl)-amine, retardation of second cleavage increases slowly with successive doublings of dose. Increasing the concentration beyond 1.040 mM rapidly decreases the percentage of eggs which divide.

5. The course of events in eggs exposed at the beginning of prophase, and later in the first and subsequent mitotic cycles points to a general slowing of mitosis. Any phase of mitosis can be blocked, depending upon the dose and time of exposure.

6. There is no synergism between urethan and methyl-bis-(-chloroethyl)-amine when they are combined in threshold doses.