Further Chemical Aspects of the Sensitization and Activation Reactions of Nereis Eggs

1. Inhibition of activation of Nereis eggs by trinitrophenol, with concurrent sensitization of the eggs to subsequent stimulation, appears to depend on the nitrogroup in the para-position on the phenol. 2. The rate of the sensitization process is enhanced by anoxia, CO2, inhibitors of the cytochrome system, or increased potassium ion concentration, but is insensitive to several other inhibitors, narcotics, stimulating agents, and to calcium ion deprivation. 3. The immediate initiation of activation by various chemical procedures requires the presence of the calcium ion, is assisted by the potassium ion, `and slightly depressed by increasing magnesium ion concentration, but is not affected by anoxia or by various metabolic poisons. 4. Subsequent nuclear and cytoplasmic reorganization, ensuing some minutes after the initial disturbance, is reversibly inhibited by anoxia, inhibitors of the cytochrome system, or diethyl ether. 5. Urethane and iodoacetate activate the eggs; this activation is inhibited by trinitrophenol. Cupric ion and p-chloromercuribenzoate also activate the eggs, but only at nearly lytic concentrations, and the activation is not affected by trinitrophenol. 6. These data are partly interpreted in relation to the hypothesis of an activator metabolite produced within the egg.