Histochemical and immunohistochemical characterization of exocrine cells in the foregut of the red-eared slider turtle, Trachemys scripta (Emydidae)

Abstract

have a secretion similar to that of the neck cells of the fundic glands, consisting of stable, class-III mucins mostly sialylated with a high heterogeneity of residuals such as glucose and/or mannose, fucose, GlcNAc, and GalNAc. Mucins in the foregut are probably involved in several functions such as lubrication, protection against gastric juice, osmotic regulation to increase intestinal absorption, and protection against microbial injuries.

Mucin in epithelial cells in oesophagus and stomach of black tetra, Gymnocorymbus ternetzi (Characidae, Teleostei)

“…The knowledge about the detailed composition of the carbohydrates in the oesophageal mucin glycoproteins in species from evolutionary old teleost orders like Characidae seems at present to be scarce and fragmented. Generally, WGA lectin is regarded to have strong affinity to Nacetylglucosamine and a putative affinity to sialic acid in terminal positions connected to the N-acetylglucosamine; PNA is believed to connect strongly to galactose-Nacetylgalactosamine sequences, DBA reacts with Nacetylgalactosamine, whereas Concanavalin A is specific for glucose/mannose (Bhavanandon and Katlic 1979;Sato et al 1991;Scillitani et al 2008). Thus, the present results for the lectin affinities in mucus cells in oesophagus of black tetra together suggest that this mucin contains significant amounts of N-acetylglucosamines, galactose-Nacetylgalactosamines sequences, and probably some sialic acid in terminal positions attached to the N-acetylglucosamine, but it seems nearly or entirely to lack glucose and mannose.…”

“…For lectin histochemistry, dewaxed sections were exposed to 3 % hydrogen peroxide for 10 min to inhibit endogenous peroxidase activity and then incubated for 60 min at room temperature with peroxidase-conjugated wheat germ agglutinin (WGA lectin) for N-acetylglucosamine, Dolichos biflorus agglutinin (DBA lectin) for Nacetylgalactosamine, peanut agglutinin (PNA lectin) for galactose-N-acetylgalactosamine, or Concanavalin A lectin for glucose/mannose (Sigma, St. Louis, USA) in 0.1 M Tris-buffered saline (pH 7.4), lectin concentration 0.02 mg/ ml (Scillitani et al 2008). Controls were performed by incubating the sections in Tris-buffered saline solution without the lectins.…”

“…Some of the dewaxed sections were incubated in 0.1 U/ml neuraminidase (Type V from Clostridium perfrigens, Sigma, St. Louis, USA) in 0.05 M acetate buffer, pH 5.5, containing 0.1 % calcium chloride at 37°C for 21 h, before the hydrogen peroxide treatment and lectin histochemistry described above (Leathem and Atkins 1983;Scillitani et al 2008). Controls were performed by incubating the sections in 0.05 M acetate buffer (pH 5.5) containing 0.1 % calcium chloride, but lacking neuraminidase.…”

“…The lectins wheat germ agglutinin (WGA lectin), Dolichos biflorus agglutinin (DBA lectin), peanut agglutinin (PNA lectin), and Concanavalin A were chosen as tools in the study of carbohydrate composition and pattern of oesophagus and stomach mucin in black tetra, as these lectins together display the most common and most studied mucin carbohydrate types hitherto known in mammals (Scillitani et al 2008).…”

Argentaffine Cells in the Digestive Tract of Hibernating and Non-hibernating in Chinese Fire-bellied Newt (Cynops orientalis)

“…Its main secretion, 5-hydroxytryptamine (5-HT), has a strong function in the regulation of digestive by stimulating vascular contractions of smooth muscle and vasodilatations (Lange, 1973;Solcia et al, 1975;El-Salhy & Lundquvis, 1985;Arena et al, 1990). At present, many scholars have investigated the argentaffine cells in the digestive tract in fishes, amphibians, reptiles and mammals (El-Salhy & Lundquvis; Patent & Epple, 1967;Carvalheira et al, 1968;Perez-Tomas et al, 1989;Arena et al;D'Este et al, 1994), moreover, they have studied the gastrointestinal endocrine cells by immunohistochemical methods and medical experiments (Eissele et al, 1997;Scillitani et al, 2008). There were littlefocused on argentaffine cells in Chinese fire-bellied newt.…”