The action of certain polysaccharides on fertilization in the sea urchin egg

Abstract

1. 1. Several polysaccharides were tested for their action on fertilization in the eggs of Arbacia punctulata and Echinarachnius parma. 2. 2. One sample of heparin (from Hynson, Westcott, and Dunning Co.); a mucopolysaccharide, the human H substance, extracted from pig mucin; and “fucoidin,” a polysaccharide preparation from Fucus vesiculosis, inhibited elevation of the fertilization membrane in relatively low concentrations. Heparin from the Upjohn Co. and also from the Vitrum Co. were relatively inactive. Heating the solutions of Upjohn and Vitrum heparin increased their activity. Oxidation of these polysaccharides with appropriate concentrations of sodium periodate removed their inhibiting activity. 3. 3. Using Hynson, Westcott, and Dunning heparin and Arbacia punctulata eggs the following information was obtained: a) 0.2 per cent heparin prevents cleavage if the eggs are fertilized in the heparin solution. b) If the eggs are fertilized in sea water and then placed in 0.2 percent heparin three to five minutes after fertilization, cleavage occurs. This is true also if the fertilization membrane and hyaline layer are removed to allow penetration of the heparin to the fertilized egg surface. c) Heparin inhibits membrane elevation in eggs from which the jelly coats have been removed. d) Heparin inhibits the membrane elevation which normally occurs when Arbacia punctulata eggs are activated with hypertonic sea water. These results are interpreted as an indication that heparin can prevent cleavage by inhibiting normal fertilization. Also, the heparin has, at least in part, an action on the protoplasmic surface of the egg. 4. 4. Possible chemical mechanisms which might explain the inhibiting activity of heparin are discussed.