THE AGGLUTINATION OF STARFISH SPERM BY FERTILIZIN

Abstract

Four species of starfish were examined, namely Patiria miniata, Astropecten sp., Pisaster ochraceus and Asterias forbesii. In accord with most other workers it was found that no agglutination occurred when sperm of these forms was mixed with homologous fertilizin. However, when sperm, homologous fertilizin and an "adjuvant"" (Panulirus, Crassius, hen or rabbit serum; hen''s egg white) were mixed, agglutination resulted. Heter-ologous fertilizin was ineffective. Patiria gave the strongest reaction and proved to be the most dependable form. Asterias gave the weakest and least satisfactory agglutination. The reaction provided a means for studying Patiria fertilizin and sperm and the relationship between them. The experiments showed that the normal adjuvant-free fertilizin reacted with and was capable of agglutinating the sperm. Thus the fertilizin is multivalent (each molecule contains two or more combining groups complementary to antifertilizin). Therefore, fertilizin agglutination of sperm fails to occur in the absence of adjuvant because of some deficiency of the sperm. It is suggested that the exposed antifertilizin of the untreated spermatozoan is limited in extent or consists of only a single molecule or reacting group. Treatment with adjuvant converts such "univalent" spermatozoa to a multivalent form by "exposing" inactive or latent antifertilizin.