Cytochemical analysis of lectin labeling in mantle epithelial cells of Loligo vulgaris, Loligo forbesi and Sepia officinalis embryos and juveniles

Summary

This paper describes the results of a histochemical study in which fluorescein isothiocyanate (FITC) labeled lectins served as reagents to detect and characterize carbohydrate containing macromolecules in mantle epithelial cells of Sepia officinalis, Loligo vulgaris and Loligo forbesi embryos and juveniles. According to these results the application of FITC labeled lectins is an effective method for characterizing cells and organs in decapod cephalopod embryos. In the mantle epithelium of all species examined, the cells of Hoyle's organ (CHO) could very easily be distinguished following application of UEI lectin. Because the UEI binding sites are probably exclusively restricted to CHO granules our investigations provide some circumstantial evidence that the hatching enzyme of L. vulgaris, L. forbesi and S. officinalis is a α-L-fucose containing glycoprotein. The most suitable lectin to label the hemispheric-apex cells (HC) appeared to be Con A because no other cells in the mantle epithelium were stained with this agent. The Con A binding sites were found in the cell coat and in the supranuclear region of the cell, probably inside the granules. Most likely the positive reaction can be ascribed to glucose or mannose residues. From our present results it can be concluded that HC and CHO are not only readily distinguishable morphologically but they can also be identified by their specific carbohydrate characteristics.

Keywords:

• embryonic ectoderm
• Hoyle's organ
• hatching gland
• cephalopods (Loligo vulgaris, Loligo forbesi, Sepia officinalis)
• lectins