ABSTRACT
Treatment of sturgeon eggs with the polyspermy-inducers urethane, ethyl ether, and acetone prolongs the latent period of the cortical reaction and apparently retards the actual secretion of the cortical granules.
On activation of sturgeon eggs by pricking and of trout eggs by immersion in water, they lose their fertilizability at the moment of the discharge of cortical granules (the content of the alveoli) in the micropylar region. Before this no decrease in ability of the egg cytoplasm to accept a spermatozoon is observed.
After removal of the perivitelline fluid (containing substances discharged from the cortical alveoli) penetration of numerous spermatozoa into activated trout eggs becomes possible.
Perivitelline fluid of trout causes an agglutination of spermatozoa.
The data obtained provide evidence that the block to polyspermy in fishes is a one-step process realized by means of the discharge of cortical granules (the content of the alveoli).
In autumn 1960 the sperm-agglutinating agent in the perivitelline fluid of trout was shown to be inactivated by trypsin (by 0·1 per cent, trypsin solution in 1 per cent. NaHCO 3 in 15–20 seconds and by 0·001 per cent, solution in 6 minutes at 4.0° C.) and by boiling (in 1 hour-1 hour 40 minutes). These data suggest that the agglutinating agent is protein in nature.
