A carbohydrate-based mechanism of species recognition in sea urchin fertilization. P.A.S. Mourão. Braz J Med Biol Res 2007; 40: 5-17.   

Figure 5. Experimental approach used to distinguish between the bindin and the carbohydrate-based mechanisms of sperm-egg recognition in sea urchin fertilization. A, Successful fertilization among three Strongylocentrotus species using sperm diluted in sea water (A-1) and pre-reacted with conspecific egg jelly (A-2). B, Structures of sulfated fucans isolated from the egg jellies of sea urchins and their effects as inducers of the acrosome reaction. The sulfated fucans were used at a concentration of 100 µg hexose/mL. Note that this is a higher concentration of sulfated polysaccharide than those used in the experiments in Figure 4. Egg jellies of S. purpuratus contain two isoforms of sulfated fucans shown in the panel. Data modified from Biermann et al. (50) (printed with permission from Blackwell Publishing). See text for further details.