Diffusible highly glycosylated protein from Bufo arenarum egg‐jelly coat: Biological activity

Abstract

L-HGP is a highly glycosylated protein from Bufo arenarum egg-jelly coat that diffuses into the surrounding medium when the strings of oocytes are incubated in saline solutions. L-HGP was purified from egg water and the estimated percentage of L-HGP/total protein in egg water was estimated in 30%. In the present study we examine, by indirect immunofluorescence, the effect of L-HGP on acrosome status of homologous spermatozoa. A high percentage (77%) of sperm lost the acrosome when incubated in 10% Ringer solution buffered with 10 mM Tris-HCl, pH 7.6, during 60 min, a condition that resembles egg-jelly osmolarity. The addition of purified L-HGP to the incubation medium prevents acrosome breakdown. The acrosome integrity is maintained for at least 1 hr. This effect is specific for L-HGP at concentration ranging from 0.01 to 0.1 mg/ml since neither BSA nor fetuin seems to have similar activity at similar concentrations. The same effect was observed when spermatozoa were incubated in egg water. Preliminary results suggest that L-HGP binds to B. arenarum spermatozoan membranes.

Vitelline Envelope of Bufo arenarum: Biochemical and Biological Characterization1

“…These results are coherent with the findings of Arranz and Cabada [44], who reported a protective effect of egg jelly molecules on acrosome integrity. It is possible to assume that once sperm are released through the male cloaca during amplexus into the surrounding medium, acrosomal breakdown would be avoided as they move through the jelly coat; this would allow sperm to reach the VE with an intact acrosome.…”

Acrosome Reaction-Mediated Motility Initiation That Is Critical for the Internal Fertilization of Urodele Amphibians

“…It is a source of divalent cations for the sperm-egg interaction (Katagiri 1987 ;Takayama-Watanabe et al, in press ), and proteinaceous components also have signifi cant roles in the interaction (Arranz and Cabada 2000 ;Olson et al 2001 ;Watanabe et al 2009Watanabe et al , 2010. Interestingly, some components such as AR-inducing substance (ARIS) seem to localize in a species-specifi c manner (Watanabe and Onitake 2002 ), suggesting that the function of the jelly layer in fertilization is modifi ed among amphibians.…”

Glycopattern analysis and structure of the egg extra-cellular matrix in the Apennine yellow-bellied toad, <i>Bombina pachypus (Anura: Bombinatoridae)</i>

“…Polylactosamine chains, usually fucosylated or sialylated, can be involved in water retention, the presentation of glycan for interaction with lectin-like receptors, and in mucin/microorganism interactions [59]. J 5 is the outermost jelly coat and is probably involved in the adhesion and spacing between eggs, as well as in storing diffusible molecules involved in fertilization, something that has been observed in other species [14,27,[63][64][65]. Its structural functions are suggested by the presence of N-linked glycans and mannosylated residues that can form the core of these glycans, as observed in the J 1 layer.…”