BINDING OF A LABELED LECTIN FROM THE LICHEN XANTHORIA-PARIETINA TO ITS OWN PHYCOBIONT AND ANALYSIS OF ITS ENZYMATIC-ACTIVITY

A partially purified algal-binding protein (ABP) has been purified fro m Xanthoria parietina thalli. This algal-binding protein behaves as a phytohaemagglutinin against human erythrocytes and contains arginase a ctivity. About 30% of ABP is labelled by using saturating concentratio ns of ferritin or fluorescein, by ramdomized chemical interaction. Lab elled ABP binds to 24%-30% of Xanthoria phycobionts when they contain particulate urease activity in their cell walls, induced by culturing algae on urea. About 88% of algal cells containing cell wall-urease bi nd purified ABP This binding diminishes ABP arginase activity as well as urease activity in algal cell walls. No significant ultrastructural alterations of whole thallus or algal cells have been observed after incubation on urea.