Inhibition of Sea Urchin Fertilization by Plant Lectins

Abstract

Effects of plant lectins on sea urchin (Lytechinus variegatus) fertilization and a partial characterization of lectin-binding involved in the process were evaluated. IC50 doses for inhibition of fertilization varied from 4.1 to 135.5 microg/ml when the lectins were pre-incubated with sperms and from 0.7 to 33.4 microg/ml when pre-incubated with eggs. Such effects were reversed when the lectins were heat inactivated. FITC-labeled lectins bound egg surfaces while their denatured forms did not. Glucose/mannose specific lectins bound weaker to eggs when pre-incubated with the glycoprotein bovine lactotransferrin. None of the glycoproteins assayed diminished FITC patterns of the Gal/GalNAc binding lectins. Pre-incubation of Glucose/mannose binding lectins with eggs did not alter binding of Gal/GalNAc lectins. Lectins with distinct competencies for binding monosaccharide and glycoconjugates were able to inhibit sea urchin fertilization.

Benzodiazepine Interference with Fertility and Embryo Development: A Preliminary Survey in the Sea Urchin Paracentrotus lividus

“…No matter if obtained from pre-treated gametes or a fertilization exposure, blastomeres lose N-Acetyl-glucosamine and α-linked fucose; meanwhile, only in the morulae derived from pre-treated gametes, there is an increase in α-linked mannose in both blastomeres and the fertilization membrane. In the sea urchin, carbohydrates are essential for cellular interactions and, among these, both fucose and mannose play an important role in spermegg interaction [54,55] and in early embryogenesis, as demonstrated by the disrupting effect of exposure to inhibitors of glycoprotein/proteoglycan synthesis [56] or binding to specific lectins [57]. Particularly significant is the fact that sugar variations are independent of DLZ concentration; in fact, they are manifest also in 1 and 5 µg/L samples, those in which fertilization percentage was as in controls.…”