Abstract

Strombidae are marine benthic gastropods, some species of which are staple foods in the Caribbean. The digestive gland of Strombidae performs various functions, some well identified, like the digestion of food particles or secretion of enzymes for extra cellular digestion, and some others for which knowledge is scarce, like the regulation of some mineral elements and detoxification pathways. The epithelium of the digestive tubules is constituted by three cell types: digestive cells, vacuolated cells, and crypt cells. In this study, ultrastructural analysis of the digestive gland cells of two Strombidae, Strombus gallus L., 1758, and S. gigas L. 1758 was performed by TEM. For both species, crypt cells were characterized by the presence of a large quantity of typical concentrically layered mineral inclusions called spherocrystals surrounded by an important rough endoplasmic reticulum. Spherocrystals were analyzed by EELS. We detected the presence of Ca2 + and Fe2 + either simultaneously in the same spherocrystal or independently inside spherocrystals containing only one of these elements. Crypt cells have been described in Molluscs as a secretion cell type. They may contain mineral inclusions described as spherocrystals or spherules which incorporate calcium in concentrical layers. Taïeb and Vicente (1999) attribute to these structures a function of osmoregulation and/or detoxification of trace-metals in Aplysia punctata. Here we highlight the possibility of a regulation way of Ca2 + and Fe2 + in crypt cells of the digestive gland of two Strombidae of the Caribbean area.

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