. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 230 M. SOUSA AND C. AZEVEDO. 16 Figure 16. When observed by scanning electron microscopy, the jelly coat was seen to be formed by large dense fibrous structures that progressively branched (arrow to triple arrow) to give origin to the inner fine fibnllar network (*). Bar = ^m. Discussion Despite the intensive biochemical characterization of the echinoderm JC, the differentiation of its components at the ultrastructural level is not well known. In the sea urchin, RR staining distinguished between amorphous and fibnllar co
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 230 M. SOUSA AND C. AZEVEDO. 16 Figure 16. When observed by scanning electron microscopy, the jelly coat was seen to be formed by large dense fibrous structures that progressively branched (arrow to triple arrow) to give origin to the inner fine fibnllar network (*). Bar = ^m. Discussion Despite the intensive biochemical characterization of the echinoderm JC, the differentiation of its components at the ultrastructural level is not well known. In the sea urchin, RR staining distinguished between amorphous and fibnllar components (Kidd, 1978), and Bonnell and Chandler (1990) demonstrated, by platinum replicas, that the fibrillar material corresponded to the fucose-sulfate- rich polysaccharide responsible for inducing the acrosomal reaction of the spermatozoon (SeGall and Lennarz, 1979). In the present study, RR and Ab stained a fibrillar ma- terial in the JC of M. glacialis oocytes; this material forms a branched matrix all around the oocyte and contains amorphous aggregates between its interstices. At fertiliza- tion, the spermatozoon bound and reacted over the fi- brillar material, whereas the amorphous aggregates dis- solved as the acrosomal process penetrated the jelly layer. RR is known to precipitate GAGs, acidic polysaccharides, and polypeptides, but not neutral polysaccharides (Luft, 1966), whereas at neutral pH and in the presence of MgCl2, Ab selectively stains GAGs (Reale et ai, 1986). Thus the amorphous aggregates probably correspond to neutral polysaccharides and the fibrillar component to acidic polysaccharides, with the possibility that this latter material may contain GAGs. The acidic nature of the fibrillar material was also demonstrated by the presence of surface negative charges, as shown by CCIC staining and by the fact that it bound calcium (Sousa and Azevedo, 1989b). TA and PTA techniques for complex carbohy- drates stained both JC components. The absence of stain- ing wit
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