Lytic Agents of the Sperm of Some Marine Animals

This thesis consists primarily of investigations of lytic agents and related substances that are extracted from sperm of echinoderms, molluscs and mammals. Sea-urchin fertilizin is found to give a mucin clot reaction with serumprotein to give a stable turbidity. Hyaluronidase, from mammalian sperm, has no dissolving action on sea-urchin egg jelly, nor could a hyaluronidase-like substance, capable of dissolving sea-urchin jelly, acting on purified fertilizin preparations or on hyaluronic acid, be extracted from sea-urchin sperm. The presence in sea-urchin sperm extracts of egg surface lysin activity is confirmed. The egg membrane lysin of sperm of the giant keyhole limpet is found to be separable from antifertilizin. Lysin is released from living sperm in sea water at neutral and alkaline pH. Antifertilizin does not appear to be released under these conditions. Release of lysin seems to be independent of metabolic activity. The lysin does not seem to act catalytically. It is inactivated by treatments that denature proteins, and by proteolytic enzymes. The egg membrane is dissolved by SH compounds and is slightly digested by trypsin. It is thought to be of keratin-like nature. It is shown that complete dissolution of the egg membrane is not necessary for fertilization. An egg membrane lysin is demonstrated in sea-urchin sperm extracts. It dissolves the keyhole limpet egg membrane. Cross reactions are shown to occur between sperm extracts and egg membranes of the keyhole limpet, abalone and mussel.