Immunologically related lectins from stems and roots of developing seedlings of Cucurbita ficifolia: purification and some properties of root and stem lectins

Abstract

Hemagglutinating activity has been found in acetate extracts from roots and stems of squash seedlings (Cucurbita ficifolia). The hemaglutinating activity changes during seeds germination and seedling development. Dot blot and Western blot techniques have shown that proteins from these vegetative tissues cross-reacted with antibodies raised against endogenous cotyledons lectin CLBa and Con A.Lectins were isolated from stems and roots of 6-day old seedlings by precipitation with ethanol, affinity chromatography on Con A-Sepharose, gel filtration on Bio-gel P100 and separated by electrophoresis on polyacrylamide gel. Three purified lectins (RLA₁, RLA₂, RLA₃) were obtained from roots and four from stems (SLA₁, SLA₂, SLA₃, SLA₄). The purified lectins from roots and stems agglutinated all human red blood cells, but sheep erythrocytes were most sensitive to agglutination. The hemagglutination of the root lectins RLA₂ and RLA₃ was inhibited by a very low concentration of arabinose, while RLA₁, of xylose and Ga1NAc. Arabinose and Xylose were also found to be the most effective inhibitors of all stem lectins.