18 research outputs found
Lectin histochemistry of salivary glands in the Gian t An t-eater (Myrmecophaga tridactyla)
The submandibular and buccal glands of the
Giant Ant-eater (Myrmecophaga tridactyla) have been
studied by means of a series of carbohydrate
histochemical methods, including a broad spectrum of
PO-lectin procedures. The seromucous cells (Gl.
submandibularis) and mucous cells (Gl. buccalis) of the
glandular acini, as well as the secretion in the excretory
duct system exhibited very strong to strong reactions for
neutral and acidic glycocongugates. The serous cells of
the buccal glands and the excretory duct cells reacted
rather weakly. The different controls applied particularly
emphasized that sialoglycoconjugates are the
predominant ingredients of the saliva secreted.
Lectin histochemical differentiation demonstrated
a varying pattern of saccharide residues in these
substances. In the submandibular glands the
glycocongujates (mostly proteoglycans) of the
seromucous cells and the luminal secretion normally
contained terminal B-galactose and minor contents of
terminal a-N-acetylglucosamine. After sialidase
digestion this cell type exhibited distinct amounts of
sialic acid-B-galactose and sialic acid-a-N-acetylgalactosamine.
Sialic acid was also clearly present in the
tough interlobular connective tissue. The buccal glands
showed a similar distribution of saccharide residues in
the mucous cells. In the serous cells, however, acidic
glycoproteins with sialyl residues were observed, also
containing terminal a-D-mannosyl, a-N-acetylgalactosaminyl,
and B-D-galactosyl residues. The cells
of the excretory duct system of both gland types reacted
weakly to moderately for terminal sugar residues (Nacetyl-
D-glucosamine, N-acetyl-D-galactosamine, B-Dgalactose).
The results obtained are discussed in view of the
specific feeding mode of the Giant Ant-eater, whereby
high contents of sialoglycoconjugates (proteoglycans,
glycoproteins) produced by the salivary glands warrant for the main function of the non-sticky saliva; i.e., to act
as an effective lubricant during tongue movement