Fine structure of egg extracellular matrix in some Anura. The fine structure of the extracellular matrix (ECM) was studied in the eggs of three Italian Anura, Pelophylax kl. esculentus, Bufo balearicus and Bufo bufo by electron-transmitted microscopy. Freshly-layed eggs were included in Epon-Araldite and ultrathin sections were obtained for TEM observations. The three species share an inner fecundation envelope (FE) The FE shows sparse granules and fibres with no clear orientation. In the jelly envelope, two layers (J1, J2) are observed in B. bufo and Pelophylax kl. esculentus, and only one in B. balearicus. In the J1 layer of B. bufo granules prevail, whereas in the J2 fibers are more abundant, run parallel to the egg’s surface, and are shared with other eggs, forming the jelly ribbon. Granules also prevail in P. kl. esculentus J1, whereas in the J2 a loose arrangement of fibres without orientation is seen. The jelly layer of B. balearicus presents granules and fibers without clear orientation. The number of layers observed correspond to those reported by histochemical studies in light microscopy in B. bufo and B. balearicus, whereas in P. kl. esculentus the histochemical approach reveals a higher number of layers, possibly due to different composition of granule and fibers among different levels in the same layer.
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|Titolo:||Ultrastruttura della matrice extracellulare ovulare di alcuni Anuri (Anura).|
|Data di pubblicazione:||2013|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|