CELL-CELL-RECOGNITION DURING FERTILIZATION IN ECTOCARPUS-SILICULOSUS (PHAEOPHYCEAE)

Two cellular communication systems are involved in sexual recognition of complementary gametes of Ectocarpus siliculosus. The first is media ted via the pheromone ectocarpene and is not species-specific. A secon d system has been identified which is based on the interaction of carb ohydrate and carbohydrate receptor. Cell fusion is inhibited selective ly by wheat germ agglutinin (WGA) applied to female gametes or with th e complementary N-acetylglucosamine (GlcNAc) applied to male gametes. Both, WGA and GlcNAc showed gametic specificity in their effects. Fert ilization was not affected by the lectins GNA, LCA and SBA. The maximu m fertilization success was 50.2% and followed Michaelis-Menten-kineti cs (I50 = 6 minutes).