Ultrastructure of ovary and oogenesis in Chamelea gallina (Linne, 1758) (Bivalvia, Veneridae)

Abstract

This is an ultrastructural study of the development of oocytes in the female venerid clam Chamalea gallina that is an economically valuable species. Specimens were collected from the Western Black Sea and the ultrastructural changes from oogonia to mature oocytes are described. The interfollicular tissue between the acini of the ovary of this species is composed of vesicular connective tissue, and a small number of follicle cells surround previtellogenic oocytes completely and move towards the stalk area at the late vitellogenic stage. Vitellogenesis may occur autosynthetically within the collaboration of Golgi complex, mitochondria. and rough endoplasmic reticulum from the previtellogenic stage to the formation of mature egg. Besides autosythetic activity, intense endocytotic activity contributes to vitellogenesis heterosynthetically from the late vitellogenic stage to the end of yolk deposition. Despite high nuclear blebbing activity that is assumed to be performed to provide the necessary membrane for vesicule fort-nation, oogenesis in C gallina is similar to that in many bivalve species studied so far.