Thermal Activation of the Dehydrogenase Systems of the Unfertilized and Fertilized Eggs of the Sea Urchin, Paracentrotus lividus

Abstract

Runnström¹ and Örström² were the first to try to compare the dehydrogenase activity in the sea urchin egg (Paracentrotus lividus) before and after fertilization by means of methylene blue reduction experiments. They could not reveal any difference. However, Ballantine³, carrying out similar experiments, was able to demonstrate a rise in the rate of methylene blue reduction in the sea urchin Arbacia punctulata ranging from 2·2 to 3·7 times. In 1939 Miss Inger Stordal, in preliminary experiments in collaboration with one of us (P. E. L.), proved the methylene blue reduction by fertilized eggs to have a higher temperature coefficient than that of the unfertilized egg. The completion of these experiments was postponed because of the outbreak of war.