Screening of agglutinins in marine algae from Fujian coast of China

Thirty-three species of marine algae belonging to Rhodophyta, Phaeophyta and Chlorophyta from the Fujian coast were examined for agglutinins with different animal and human erythrocytes. Protein extracts from 26 species were active against at least one type of the erythrocytes tested. There were 3 species (Grateloupia imbricata, Ishige foliacea andEntermorpha prolifera) whose extracts could agglutimate all the erythrocytes used. The lowest protein concentration required to produce erythrocyte agglutination varied remarkably, from 3.1 μg/ml to 500 μg/ml. The strongest activity was found in the agglutination of rabbit erythrocytes byGloiopeltis furcata extract. Inhibition assays performed with nine mono- and bisaccharides indicated that agglutinations of rabbit erythrocytes by extracts of 7 species were inhibited by one or more types of the sugars assayed. The agglutinating activity shown by extracts of most species was not affected when the test solution was heated to 90°C, but was lost at 95°C–100°C. A few extracts lost their activity at 60°C, 65°C and 75°C, respectively.