We studied the organization of the egg of a freshwater bivalve, Unio elongatulus. This egg is markedly polarized. At the vegetal pole there is a crater which constitutes the point of attachment of the growing oocyte to the ovarian wall. This has previously been interpreted as a micropyle. We show that the sperm does not enter the egg through the crater but in a differentiated region around it, mostly at its base. This region is characterized by a wrinkled surface and is the only site of the vitelline coat which specifically binds the lectin from Lotus tetragonolobus. The egg reacts explosively upon fertilization, ejecting vacuolar material from the crater. The role of this "egg reaction" in relation to the prevention of polyspermy is discussed. © 1988.

Focarelli, R., Renieri, T., Rosati, F. (1988). Polarized site of sperm entrance in the egg of a freshwater bivalve, Unio elongatulus (Mollusca, Bivalvia). DEVELOPMENTAL BIOLOGY, 127(2), 443-451 [10.1016/0012-1606(88)90330-2].

Polarized site of sperm entrance in the egg of a freshwater bivalve, Unio elongatulus (Mollusca, Bivalvia)

FOCARELLI, R.;RENIERI, T.;ROSATI, F.
1988-01-01

Abstract

We studied the organization of the egg of a freshwater bivalve, Unio elongatulus. This egg is markedly polarized. At the vegetal pole there is a crater which constitutes the point of attachment of the growing oocyte to the ovarian wall. This has previously been interpreted as a micropyle. We show that the sperm does not enter the egg through the crater but in a differentiated region around it, mostly at its base. This region is characterized by a wrinkled surface and is the only site of the vitelline coat which specifically binds the lectin from Lotus tetragonolobus. The egg reacts explosively upon fertilization, ejecting vacuolar material from the crater. The role of this "egg reaction" in relation to the prevention of polyspermy is discussed. © 1988.
Focarelli, R., Renieri, T., Rosati, F. (1988). Polarized site of sperm entrance in the egg of a freshwater bivalve, Unio elongatulus (Mollusca, Bivalvia). DEVELOPMENTAL BIOLOGY, 127(2), 443-451 [10.1016/0012-1606(88)90330-2].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/31259
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo