Oviductal calcium dynamics during the reproductive cycle of Pomacea canaliculata (Gastropoda: Prosobranchia)

CATALÁN M; WINIK BC; FERNÁNDEZ SN

Córdoba

Congreso; First Meeting of Argentine Biology Societies; 2008

Sociedades de Biología de la República Argentina

OVIDUCTAL CALCIUM DYNAMICS DURING THE REPRODUCTIVE CYCLE OF Pomacea canaliculata (Gastropoda, Prosobranchia) Catalán M, Winik B, Fernández S. Facultad de Ciencias Naturales e IML. UNT. E-mail: catalan@csnat.unt.edu.ar In Pomacea canaliculata, aerial egg deposition is associated with the presence of a calcareous shell that protects embryo from desiccation. The main calcium deposit involved in the egg-shell formation is the glandular complex of the pallial oviduct. The aim of this work is to analyze the variations in contents and distribution of oviductal calcium during the annual reproductive cycle. Samples were conventionally processed for transmission electronic microscopy. During the reproductive period (September-March), an intense tissular calcic infiltration, calciferites which reach their maximal volume, and calcic particles between cell folds can be seen. Associated with these observations, there is an evident calcium mobilization towards the ductal lumen and calcified cell extrusion. In the post-reproductive period (April), scarce remnant calciferites and empty ductal lumens can be observed. In the pre-reproductive period (May-August), occur the crystallization of nuclei and an increase in number of size of calciferites. The extracellular space between the laberynthic cells and the ductal lumens are lacking of calcic material. Conclusions: Deposits of oviductal calcium exhibits cyclic variations in relation to the reproductive activity. This cation is movilized and enters massively the ductal lumen for the formation of the egg-shell in the reproductive period. Calcic reserves decline notoriously; and basal labyrinth and ductal lumens are left empty in the post-reproductive period. Calcium storage activates, there is calciferite formation and growth, but calcium does not enter ductal light in pre-reproductive period.