Sperm isoagglutination and sialic acid content of the jelly coat of sea urchin eggs

Histochemical studies of jelly coat of sea-urchin eggs during oogenesis

Jelly coat of sea-urchin eggs consists of polysaccharides and glycoproteins. Some properties of jelly coat have already been investigated, but not histochemically. The oogenesis in Paracentrotus lividus was studied histologically and the oocytes were classified into six different stages. The extracellular jelly appeared first around the growing oocytes II which remained attached to the germinal epithelium. The jelly became thicker when the oocyte approached maturation. Histochemical analysis revealed that the jelly consists of mucopolysaccharide-protein-complexes. The polysaccharide component is composed of both neutral and acid mucopolysaccharides. The former are amylase-resistant. The acid mucopolysaccharides contain both carboxyl and sulfate groups, which are in close proximity to vicinal hydroxyl groups. Sulfated mucopolysaccharide is hyaluronidase-resistant. Sialic acid could not be clearly demonstrated, because it seems to be resistant to neuraminidase. Pepsin digestion indicated the masking of acidic groups by proteins which compete with basic dyes (Alcian blue, Azure A, coriphosphine etc.). Proteolytic digestion enhanced dye-binding ability of jelly, but removed also some of the periodate-reactive mucosubstances. Also a protein component could be demonstrated histochemically. No histochemical difference between jelly coat of oocytes and that of eggs has been found. The possible molecular structure of jelly coat is discussed.

Identification of the sialic acids from the egg jelly coat of the sea urchin Pseudocentrotus depressus (Okayama)

The jelly coat substance of the sea urchin eggs of Pseudocentrotus depressus (Okayama) was found to contain 0.35% sialic acids. After isolation of the sialic acids from the purified sulfated sialoglycoprotein containing 11% of sialic acids, analysis by colorimetry, thin-layer chromatography and gas-liquid chromatography/mass spectrometry demonstrated the nature of the sialic acids to be N-glycolylneuraminic acid and 9-O-acetyl-N-glycoloylneuraminic acid. The molar ratio between both sialic acids was found to be 1 : 1. Since it is known that O-acyl groups are partially released during the hydrolysis and isolation procedure, it can be assumed that in the native glycoprotein the percentage of O-acetylation is much higher than 50%. The sugar and sulfate composition of the glycoprotein is also described.

Separation of the Sperm Agglutinin and the Acrosome Reaction-Inducing Substance in Egg Jelly of Starfish

The egg jelly of the starfish Asterias amurensis was separated into the fractions J1, J2, and J3 on a Sephadex G-100 column. The Jl fraction induced the acrosome reaction and J2 induced sperm agglutination. Chemical analysis and chromatography revealed that sperm agglutinin is similar to asterosaponin A.