Sulfated Polysaccharides from the Egg Jelly Layer Are Species-specific Inducers of Acrosomal Reaction in Sperms of Sea Urchins

Abstract

We have characterized the fine structure of sulfated polysaccharides from the egg jelly layer of three species of sea urchins and tested the ability of these purified polysaccharides to induce the acrosome reaction in spermatozoa. The sea urchin Echinometra lucunter contains a homopolymer of 2-sulfated, 3-linked ␣-L-galactan. The species Arbacia lixula and Lytechinus variegatus contain linear sulfated ␣-L-fucans with regular tetrasaccharide repeating units. Each of these sulfated polysaccharides induces the acrosome reaction in conspecific but not in heterospecific spermatozoa. These results demonstrate that species specificity of fertilization in sea urchins depends in part on the fine structure of egg jelly sulfated polysaccharide.Successful fertilization by free-spawning organisms such as sea urchins can occur only if a series of constraints are overcome before the sperm ever makes contact with the egg (1). First, males and females must synchronize the time of release of their gametes (2). Once spawned, the sperm must find and interact with an egg of the correct species. A further event necessary for successful fertilization is induction of the acrosome reaction in the sperm (3, 4), which involves fusion of the acrosomal vesicle membrane with the plasma membrane. This results in exocytosis of the vesicle contents, which include proteases and bindin. Concomitantly, actin in the subacrosomal region of the sperm polymerizes and causes extension of the tip of the sperm. As a consequence of these two events, bindin is localized to the outside of the tip of the process where it can then interact with an egg protein (3, 4).The acrosome reaction is induced when the sperms contact the egg jelly layer. The sea urchin egg is surrounded by a transparent gelatinous layer composed mainly of sulfated fucan, sialoprotein, and other glycoproteins or peptides (5). Previous attempts to identify the acrosome reaction inducer in sea urchin egg jelly have suggested that all the activity resides in the sulfated fucan (6, 7). In addition, these authors suggested that the jelly coat preparations of some species of sea urchins are totally species-specific and induce the acrosome reaction only in homologous sperm. On the basis of these observations, it was suggested that the specificity of induction of the acrosome reaction might reside in structural differences in the carbohydrate linkages and/or location and degree of sulfation of the polysaccharide (6, 7). Recent studies suggest that a glycoprotein or peptide, tightly associated with the sulfated fucan, was also involved in acrosome reaction induction (8 -11).In this study, we isolated, purified, and characterized the fine structure of the sulfated polysaccharides from the egg jelly coat of three species of sea urchins. These compounds have simple, well-defined repeating structures that from each species present a particular pattern of sulfate substitution. Purified polysaccharide from the egg jelly induces the acrosome reaction in sperm from the same species of sea urchin and not f...

Immunological Activity of Chondroitin Sulfate

“…These findings also suggest a therapeutic use of CS to control the IgE mediated allergic response. The number and position of O-sulfo groups varies among CS samples obtained from different sources (Alves et al, 1997;Farias et al, 2000;Santos et al, 1992).We hypothesized that the immunological activity of orally administered CS might also be different among the several types of CS. Thus, it is important to determine the structure-activity relationship (SAR) of CS, particularly with respect to the number and position ofO-sulfo groups in CS.…”

Structural analysis of oligosaccharide‐alditols released by reductive β‐elimination from the jelly coats of the anuran Bufo arenarum

“…Thus modifications of the anuran egg extracelmoieties mediate sperm-zona pellucida interaction in mice [2], lular matrix are fundamental processes that regulate sperm-egg hamsters [3], and rats [4]. Alves et al [5] have shown that sul-interaction in fertilization. fated polysaccharides from the egg jelly of Sea urchins are spe-…”

Structure versus anticoagulant and antithrombotic actions of marine sulfated polysaccharides

“…Among all the MSP with well-defined chemical structures described so far (Figures 1 and 2), there is a single description from the body wall of the sea cucumber ( Figure 1A) (Mulloy et al, 2004), a few examples of SG isolated from the tunic of ascidians ( Figure 2C and 2D) (Mourão & Perlin, 1987;Santos et al, 1992;Pavão et al, 1998), and some reports from specific red algal cell walls ( Figure 2E) (Pereira et al, 2005;Fonseca et al, 2008). All of the remaining structures ( Figure 1B -H and 2A and B) belong to the egg jelly coat of sea urchins (Alves et al, 1997;Alves et al, 1998;Vilela-Silva, et al, 1999;Vilela-Silva et al, 2002;Mulloy et al, 2004) The body of some species of ascidians also contains peculiar GAG that show sulfation patterns distinct from mammalian GAG (Pavão et al, 1995;Pavão et al, 1998), as exemplified by the tunicate dermatan sulfates (DS) in Figure 2F.…”

“…The MSP with well-defi ned chemical structures (SF, SG and GAG in Figures 1 and 2) are extracted from echinoderms (Echinodermata) like sea cucumbers (Mulloy et al, 2004); (B) Lytechinus variegatus (Alves et al, 1997); (E) Strongylocentrotus purpuratus-I (Stimpson, 1857) (Alves et al, 1998) Vilela-Silva et al, 2002); and (H) Strongylocentrotus franciscanus (A. Agassiz, 1863) Vilela-Silva et al, 1999). (Castro et al, 2009) (Santos et al, 1992) (Mourão & Perlin, 1987); (E) both Botryocladia occidentalis (Kylin, 1931) and Gelidium crinale (Gaillon 1828) express [3-β-D-Galp-1→4-α-Gal-1→] n with different sulfation contents (Pereira et al, 2005;Fonseca et al, 2008); and (F) the DS from Styela plicata, Halocynthia pyriformis (Rathke, 1806), and Ascidian nigra (Savigny, 1816) are composed of [4-α-L-IdoA-1→3-β-D-GalNAc-1] n with also different sulfation patterns (Pavão et al, 1995;Pavão et al, 1998).…”