Glyconjugates in epidermal, branchial and digestive mucous cells and gastric glands of gilthead sea bream, Sparus aurata, Senegal sole, Solea senegalensis and Siberian sturgeon, Acipenser baeri development

Abstract

and the gastric glands of larvae/postlarvae (from hatching until 45 days posthatching) of three fish species (two teleostean and a chondrostean) were investigated using conventional histochemical methods (periodic acid schiff –PAS-, diastase-PAS; alcian blue pH 0.5, 1 and 2.5) in order to distinguish neutral and acidic (carboxylated and sulphated) glycoconjugates, as well as bromophenol blue reaction for identification of proteins. Additionally, the presence and distribution of sugar residues in the oligosaccharide side chains of glycoconjugates were investigated using horseradish peroxidase (HPR)-conjugated lectins (Con A, DBA, WGA and UEA-I). Most mucous cells (digestive, epidermal and branchial) of Siberian sturgeon, Acipenser baeri, sea bream, Sparus aurata and Senegal sole, Solea senegalensis larvae were PAS- and alcian blue- (pH 2.5 and 0.5) positive, with small variations between organs/tissues and species. Bromophenol blue reaction (general proteins) was positive in a minority of the mucous cells, usually in those cells which were PAS-negative. Proteins rich in sulphydryl (-SH) and/or disulphide (-S-S-) groups related with the glycoprotein nature of the glycoconjugates present in mucous cells were also observed. Epidermal, branchial and digestive mucous cells of all studied larvae did not contain glycogen or lipids

Vigorous SO42– influxviathe gills is balanced by enhanced SO42– excretion by the kidney in eels after seawater adaptation

“…In mammals, mucus is made from various sulfated proteins and sugars (Amerongen et al, 1998). Marine teleosts have large amounts of sulfated glycoproteins in abundant goblet cells in the digestive tract and mucus cells in the gills and skin, as shown by Alcian Blue staining (Sarasquete et al, 2001). Thus most 35 S may be incorporated into the mucus.…”

Glycohistochemical study of the toadfish <em>Halobatrachus didactylus</em> (Scheider, 1801) stomach

“…Secretion of neutral glycoconjugates containing sugar residues has been observed in the gastric glands of fish species which differ in feeding habits, habitat and biology (Gutiérrez et al, 1986;Domeneghini et al, 1998;Sarasquete et al, 2001;Pedini et al, 2005;Díaz et al, 2008). neutral glycoconjugates could represent evidence of the absorption and transport of macromolecules through the membranes (reifel and travill, 1978;Sarasquete et al, 2001;Pedini et al, 2005), whereas acid glycoconjugates prevent damage to the gut epithelium, acting as a lubricant for the stomach contents and as a buffer for the highly acidic gastric juices (Ferraris et al, 1987).…”

“…Due to their specific affinities to a particular sugar, lectins are useful probes for the intracellular localisation of sugar residues (ihida et al, 1991;Danguy et al, 1994) and for characterising cellular populations as well as their morpho-functional changes (Spicer and Schulte, 1992;Danguy et al, 1994). lectins have been successfully used to evaluate the composition of the oligosaccharides in the gastric mucosa of some marine fishes such as Solea senegalensis , Sparus aurata (Domeneghini et al, 1998;Sarasquete et al, 2001), Umbrina cirrosa (Parillo et al, 2002;Pedini et al, 2005) and Cynoscion guatucupa (Díaz et al, 2008).…”

“…Glycoconjugates secreted by the stomach constitute an important class of macromolecules because they protect the stomach epithelium from auto-digestion caused by hcl and enzymes produced in gastric glands by forming an adherent mucus gel (Ferraris et al, 1987;Smith, 1989). Moreover, glycoconjugates play a role in the absorption and transport of macromolecules through the membranes (reifel and travil, 1978;Domeneghini et al, 2005;Sarasquete et al, 2001) and dilution in ingested water (Domeneghini et al, 1998). the gastric glands of teleosts contain only one cell-type that secretes both pepsinogen and hydrochloric acid (reifel and travill, 1978; rebolledo and vial, 1979).…”

Effect of starvation on the type and distribution of mucus cells in the digestive tract of the yellow drum Nibea albiflora (Richardson, 1846)

“…The secretion of neutral glycol-conjugates containing sugar residues by mucus cells has been validated in gastric glands of various fish species (Gisbert et al, 1999;Sarasquete et al, 2001;Diaz et al, 2008). Neutral glyco-conjugates could play a critical role in protecting the epithelium of stomach from auto-digestion processes.…”