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We investigated the occurrence of endogenous lectins in the mouse submandibular gland using anti-lectin antibodies that selectively bound the respective hapten lectins which have formed a complex with the appropriate hapten sugars and endogenous lectins. Findings supported the idea that endogenous lectins could interact with sugar residues and perform several roles including packaging, immobilization and transport of glucidic material. A functional meaning in the defence from some pathogenous agents was also postulated. Animal lectins seem to play roles related to their localization like occurs in the plants.

Stainings were effected on an ultrastructural histochemical level to localize sulphomucins in the submandibular and sublingual glands of growing mice and rabbits. Sulphates behave in an entirely different way in the salivary glands of Lagomorpha and in those of Rodents. In growing rabbits sulphates can be demonstrated in both glands; at maturity they can be demonstrated only in the sublingual gland and no longer in the submandibular gland. In the salivary glands of Rodents, sulphates cannot be demonstrated histochemically in new born subjects or in adults. The histochemical results are compared to the biochemical ones, and discrepancies, where present, are discussed.

Stainings with dialized iron (DI), high-iron diamine-thiocarbohydrazide-silver proteinate HID-TCH-SP), tannic acid-uranylacetate (TA-U), tannic acid-ferric chloride (TA-F), and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) were applied to samples of sublingual glands of rabbits. Comparing the results obtained with what had been previously demonstrated biochemically, it is possible to assert that the faintly electron-opaque, granules of the cells of the preterminal tracts contain sulphated glycoconjugates because of the presence of sulphated hexosamines and hexoses, acid glycoconjugates because of the presence of sialic acid and uronic acids, and neutral glycoconjugates because of the presence of hexoses.

A histochemical study has been carried out by light and electron microscopy on the localization of the activity of arylsulphatases A and B in the salivary glands of rat. Results obtained indicate that in the submandibular gland a greater activity is present in the cells of the convoluted granular tubules than in the acina cells, whereas in the sublingual gland the cells of the preterminal tracts appear to be more reactive than those of the terminal tracts. The probable role played by these sulphatases is discussed.

We investigated the structure of glycoconjugates contained within the secretory end-pieces and ductal segments in the rabbit submandibular and sublingual glands. Glycosidic sequences were examined by means of enzymatic degradation with specific glycosidases (sialidase, alpha-fucosidase, beta-galactosidase, alpha-mannosidase) followed by lectin binding with PNL-HRP, WPL-HRP, WGL-HRP, SBL-HRP, Con A-HRP. It was found that this procedure represents a valid tool for studying carbohydrates, in so far as their characterization and localization were based only on colour reactions. In particular, this research showed that sialic acid was present in the terminal dimers sialic acid-beta-galactose and sialic acid-N-acetyl-D-galactosamine within the submandibular gland, whereas in the sublingual gland it was only present as the sequence sialic acid-beta-galactose. Conversely, fucose had as the subterminal sugar N-acetyl-D-glucosamine in both glands. Also, elucidations about structural sequences concerning other non-terminal sugars were obtained.

An ultrastructural histochemical investigation was carried out to ascertain the localization of the glucidie components and to verify the histochemical modifications during the physiological estrogenic cycle of rabbit oviduct. Stainings were performed with high iron diamine (HID), low iron diamine (LID), dialized iron (DI), tannic acid-uranyl acetate (TA-U), and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) methods. The findings indicated that the secretory activity is more intense in the isthmus than in the ampulla. Neutral glycoconjugates are localized both in the secreting elements of the ampulla and in those of the isthmus, while carboxylated and sulphated glycosaminoglycans are localized only in the secretory granules of the secreting elements of the isthmus.

A histochemical study was effected, by light and electron microscopy, on the activity of arylsulphatases A and B in the submandibular and sublingual glands of male and female rabbits, distinguishing, among the latter, between the physiological estrus and anestrus condition. The results obtained demonstrated that the enzymatic activity is more intense in the sublingual gland and that the estrus condition causes an increase in this activity. No correlation was found between the topochemical distribution of the soluble arylsulphatases and that of sulphates.

An investigation was carried out by light and electron microscopy on the localization of the carbonic anhydrase enzyme in the submandibular and sublingual glands of some rodents and lagomorpha. By means of the cobalt-bicarbonate technique, it was demonstrated that in the submandibular glands the carbonic anhydrase activity is more intense in the terminal tracts, and that in the sublingual glands the enzyme activity is present in an equal degree in the terminal tracts and in the intralobular ducts. The results obtained are compared to those of other authors, and conjectures are made as to the functional significance of the carbonic anhydrase activity in the salivary glands.

Specimens from rat ampulla and isthmus were stained with a battery of 10 lectin-horseradish peroxidase conjugates and lectin binding patterns were correlated with the distribution of periodate-reactive vicinal diol groups as determined by the PA-TCH-SP (periodic acid-thiocarbohydrazide-silver proteinate) sequence. The free surface of ciliated and non-ciliated cells was stained moderately to intensely by all lectins and PA-TCH-SP sequence. Binding sites for WGA, UEA I, LTA, Con A were also detected on the tight junctional regions. Secretory granules reacted with all stainings, except for LPA. The localization of certain sugars (sialic acid, fucose) appeared useful for understanding the functional meaning of positive sites.

An immunohistochemical study was conducted in order to visualize an endogenous lectin, having specificity for alpha-L-fucose residues, in the ampullary and isthmic tracts of the rabbit oviduct. 2 different sequences (S1 and S2) were tested using antilectin UEA I antibody. Reactive sites towards S2 sequence were localized at ciliated cell level in the ampulla; in the isthmus, instead, the staining was present both in ciliated and secretory cells. A role in the sugar immobilization and gamete and zygote protection was postulated for the endogenous lectin evidenced.