Expression pattern of glycoconjugates in the integument of Bufo ictericus (Anuran, Bufonidae): Biochemical and histochemical (lectin) profiles

Lectin binding properties of liver, small intestine and tail of metamorphosing marsh frog (Pelophylax ridibundus Pallas 1771)

In this present study, localization and variations of specific sugar moieties in the terminal carbohydrate chains of glycoconjugates in the small intestine, liver and tail have been investigated during the metamorphosis of Pelophylax ridibundus larvae. For this purpose, four lectins were used: wheat germ agglutinin (WGA), Ulex europaeus agglutinin (UEA-I), Dolichos biflorus agglutinin (DBA) and peanut agglutinin (PNA), in different larval stages of the frog. Some cells stained specifically in the intestinal mucosa and in tail epidermal cells with the lectins and their affinity changed during metamorphic transformation. For the most part, they decreased in the climax and postmetamorphic periods. It was also found that WGA, DBA and UEA-I lectins exhibited strong affinity to white blood cells in the liver and their binding affinities were the highest in prometamorphosis and they gradually decreased until the end of metamorphosis. These results suggest that the changes of lectin binding in metamorphosis may be an indication of some cellular events occurring in larval metamorphosis such as cell differentiation and damage of cell adhesion between death and differentiating cells. They also can be useful markers for detection of white blood cells in amphibian hematopoietic organs.