Histochemical distribution of four types of enzymes and mucous cells in the gastrointestinal tract of reared half‐smooth tongue sole Cynoglossus semilaevis

Abstract

The histochemical distribution of acid phosphatase (ACP), alkaline phosphatase (ALP), non-specific esterase (NSE), peroxidase (POD) and mucous-cell types was evaluated in the gastrointestinal tract of the half-smooth tongue sole Cynoglossus semilaevis. The enzymes were detected in the entire stretch of the gastrointestinal tract. ACP activity was found in the supranuclear region of enterocytes and the lamina propria of the intestine, as well as the cytoplasm of epithelial cells of the stomach. The staining intensity of ACP in the anterior and posterior intestines was stronger than in the stomach. ALP activity was detected in the striated border of enterocytes and muscularis of the whole intestine, lamina propria and supranuclear cytoplasm of the enterocytes in the anterior intestine, as well as in the blood vessels of the stomach. The staining intensity for ALP in the anterior intestine was stronger than in the posterior segment and the latter was stronger than in the stomach. NSE activity was detected in the cytoplasm of the epithelial cells in the entire gastrointestinal tract, with the anterior intestine showing stronger intensity than the stomach. POD activity was located in the blood cells of the lamina propria of the gastrointestinal tract and the levels in the stomach were similar to the anterior and posterior intestines. Alcian blue (pH 2·5) periodic acid Schiff (AB-PAS) histochemical results revealed three types of mucous cells in the gastrointestinal tract. Type I cells (PAS+AB-) were observed among the gastric mucosa columnar cells in the stomach and enterocytes in the basal region of the villi and in the middle and top regions of the intestinal villi. Type II cells (PAS-AB+) and type III cells (PAS+AB+) were not detected in the stomach but were distributed ubiquitously among enterocytes in the middle and top regions of the intestinal villi.

Activity and post-prandial regulation of digestive enzyme activity along the Pacific hagfish (Eptatretus stoutii) alimentary canal

“…Finally, we investigated alkaline phosphatase activity, which was also restricted to the hindgut, and may be utilized to demarcate between functional units of the intestine as previous [56]. Feeding resulted in a significant reduction of tissue alkaline phosphatase activity (Fig 6).…”

Mucosal Hallmarks in the Alimentary Canal of Northern Pike Esox lucius (Linnaeus)

“…In E. lucius , the neutral mucins of the columnar cells are characterized mainly by galactosyl(b1-3)-N-acetylgalactosamine residues, a finding also reported in eel [ 10 ]. The neutral mucins secreted in the stomach are related to carbohydrate and short-chain fatty acid absorption through the plasma membrane [ 3 , 24 , 30 , 43 , 44 ]. The gastric glands showed no reaction to the AB/PAS and HID/AB sequence, similar to results of other investigated species [ 30 , 41 ].…”

Comparative histochemical analysis of intestinal glycoconjugates in the blunthead pufferfish Sphoeroides pachygaster and grey triggerfish Balistes capriscus (Teleostei: Tetraodontiformes)

“…General organisation of the intestine in both species showed the basic features of the teleost intestine, with a small intestine and a rectum scarcely differentiated and goblet cells secreting neutral and acidic mucins increasing in number posteriorly (Wilson & Castro, ). The distribution and mucin composition of goblet cells varies widely among teleosts (Bočina et al ., , ; Cao & Wang, ; Çinar, K., & Şenol, ; Petrinec et al ., ; Reifel & Travill, ; Wang et al ., ) and several attempts have been made to relate the mucous composition to environmental, dietary and pathologic factors (Domeneghini et al ., ; Petrinec et al ., and references therein). Differences in the composition of the mucins observed between the sampled species probably reflect different functional requirements resulting from the agastric v .…”