Università degli studi di Modena e Reggio Emilia

The changes in the expression of glycoconjugates and adhesion molecules were studied by selective lectin binding and immunocytochemical reactions in a human embryonic epithelial cell line (EUE cells), synchronized in the cell cycle phases. The results can be summarized as follows: most of the tested lectins display a more diffuse binding for the cytoplasm in G(1) than S and G(2) phases; in the S and particularly in G(2) phases the cytoplasm glycoconjugates are rearranged around the nucleus; cells in mitosis always show a strong binding towards all tested lectins. Cellular fibronectin and its receptor beta(1) integrin are well expressed in G(1), but the strongest reaction is observed in the S phase. The immunoreactions for laminin and uvomorulin (L-CAM) are poorly positive in all cell cycle phases. The immunocytochemical reaction for heparan sulfate is positive, with a stronger reaction in S and G(2) than in G(1); on the contrary a diffuse staining with the anti-dermatan sulfate proteoglycan antibody appears unchanged during the cell cycle. (

The digestive gland of Viviparus ater was studied using histochemical and ultrastructural methods. Only one cell type was observed in the tubule epithelium of the gland. The cells are involved in an endocytotic process mediated by clathrin-coated vesicles and in the intracellular digestion of food materials (thus they can be regarded as digestive cells). The different stages of digestion and exocytotic extrusion of residual bodies into the tubule lumen were shown by electron microscopy. Very few, small myocytes are scattered among the digestive cells. Calcium concretions, glycogen-containing cells and endocrine cells are scattered in the area of connective tissue present among the digestive tubules.

The presence of endocrine cells was investigated by immunocytochemical procedures in the gut and salivary gland of Viviparus ater, a freshwater prosobranch gastropod. The endocrine cells were scanty and both of closed and open cell type. Most of them were located in the esophagus (immunostaining with antigastrin, anti-insulin, anti-serotonin and anti-substance P antisera), very few in the stomach (immunoreactive only to anti-gastrin antibody) and in proximal part of the intestine (immuno-reactive to anti-serotonin and anti-substance P antibodies). In the salivary glands, occasional endocrine cells scattered among the glandular cells in the adenomera stained with anti-neuropeptide Y, anti-pancreatic polypeptide and anti-somatostatin sera were detected.