Hemagglutinins in marine algae.

We surveyed the Japanese marine algae for hemagglutinins with rabbit erythrocytes.Algae used in this screening were 53 species; 6 species of green algae, 42 of red algae and 5 of brown algae.The results showed the presenceof the active components with strongactivities in 14 species; 4 species of the green algae, 9 of the red algae and 1 of the brown algae.The extracts of the algae which gave positive results were further examined forhemagglutinating activity againstothe r erythrocytes of animals and human A, B, Oand AB groups.Of the 14 species positive to hemagglutination with rabbiterythrocytes, 5 species showed nohemagglutinating activity with human erythrocytes.The results also indicated that the extract of a green alga Ulva arasakii reacted preferentially with erythrocytes of human A and 0 groups, and that those of both a green alga Bryopsis hypnoides and a red alga Laurencia undulata showed more specific activities with human B erythrocytes than with the others.There were no marked features in the distribution of the hemagglutinins among marine algae teated.