Search

The glycosoaminoglycans in the digestive apparatus of immature fish have important biological functions and are involved in morphofunctional differentiation. The aim of this study was to investigate the glycoconjugate histochemistry in the different parts of the digestive apparatus (oesophagus, stomach, intestine) of Umbrina cirrosa(L.) fry using classical histochemical reactions (periodic acid–Schiff, Alcian blue pH 2.5, Alcian blue/periodic acid–Schiff, high iron diamine, low iron diamine) in conjunction with glycolytic digestions that degrade different classes of glycosoaminoglycans. No differences were observed in the reactivity to conventional histochemical staining of the oesophagus, stomach or intestine among 27-, 34- or 44-day-old fry. In the oesophagus, the mucopolysaccharides contained chondroitin sulphates B and A and/or C, heparan sulphate and chondroitin. In the stomach, only neutral glycoconjugates were revealed, whereas in the intestine there were only chondroitin sulphates. Some differences in the type and content of glycoconjugates were found in Umbrina cirrosa(L.) fry compared to those of adult subjects, probably related to different dietary habits and to changes in the environmental conditions.

Sheep haemal nodes are reported to be lymphatic organs within the blood circulation. In this study they were seen to be covered by a capsule of connective tissue, with a hilus in which some blood vessels were detectable. Below the capsule a subcapsular blood sinus and lymphatic nodules were present. A reticular meshwork extended through the interior; the interstices of the reticular meshwork contained a large number of free blood cells, many macrophages, lymphocytes and plasma cells. Blood collected in the subcapsular sinus and flowed through the reticular meshwork aided by the particular alignment of some of the reticular cells in channel-like passageways. Venules originated in the parenchyma and drained into efferent veins that left the organ at various points in the capsule. A large efferent blood vessel, apparently connected with the subcapsular sinus, was present in the hilus.