Lectin binding pattern and proteoglycan distribution in human eccrine sweat glands

Cytochemistry of sialoglycoconjugates, lysozyme, and β-defensin in eccrine glands of porcine snout skin as studied by electron microscopy

In most mammals except for humanoid primates, eccrine glands are confined to the skin of a series of specific body regions. Sialic acids and antimicrobial substances exhibit various functional properties and serve as a component of nonspecific defense against micro-organisms, respectively. In this study, the distribution of these moieties was studied by electron microscopic histochemical methods. The eccrine glandular acini consisted of two types of dark cells as well as clear cells. The secretory granules and Golgi apparatus of both types of dark cells contained sialic acid residues linked to α2-6Gal/GalNAc. On the other hand, sialoglycoconjugates with Siα2-3Galβ1-4GlcNAc sequence were confined to those of the Type II dark cells. In addition, lysozyme and β-defensin were mainly detected in the secretory granules of the Type II dark cells. These secretory products may create a defensive barrier against microbial invasion and play an essential role in preservation of the integrity of porcine snout skin as a sensory organ.

Morphology and glycoconjugate histochemistry of the eccrine glands in the snout skin of the North American raccoon (Procyon lotor)

The eccrine nasolabial glands were found in the hypodermis of the nasal plane in the North American raccoon (Procyon lotor). In addition to light and electron microscopic observations, the distribution and selectivity of complex glycoconjugates in the eccrine tubular glands of the raccoon snout skin were studied using various histochemical methods, particularly lectin staining. The secretory epithelium and the luminal secretions exhibited high amounts of glycoconjugates with various saccharide residues (alpha-D: -mannose, alpha-L: -fucose, beta-D: -galactose, beta-N-acetyl-D: -glucosamine, sialic acid). The excretory duct cells also showed positive reactions with most of the histochemical methods applied. The results are discussed with regard to possible functions of the glandular secretions. The complex glycoconjugates that are produced by the eccrine nasolabial glands may be related to moistening of the skin surface as well as protecting the epidermis against physical damage or microbial contamination. This is the first report on the glands in the snout skin of carnivores.

Ultracytochemical Demonstration of Glycoproteins in the Eccrine Glands of the Digital Pads of the North American Raccoon (Procyon lotor)

In the eccrine glands of the digital pads of the North American raccoon (Procyon lotor), ultrastructural localization of glycoproteins with various saccharide residues was studied using preferably lectin cytochemical methods. Secretory granules observed in the dark cells exhibited glycoproteins with different terminal sugars (alpha-D-mannose, beta-D-galactose, beta-N-acetyl-D-glucosamine and sialic acid). The cytoplasm of the clear cells contained numerous glycogen particles. Several sugars were also detectable in the surface coat of the plasma membrane of the secretory cells. The results obtained could be helpful in understanding secretion production and cell related secretion functions of the eccrine glands of the raccoon digital foot pads.