A SURVEY OF ANTARCTIC ALGAE FOR AGGLUTININS

Abstract

Since the discovery of haemagglutinating activity in marine algal extracts in 1966, several algal haemagglutinins (lectins) have been detected, isolated and characterized. However, information is slowly emerging, concerning biochemical characteristics of lectins from Antarctic marine algae. Lectins are proteins or glycoproteins which bind, reversibly, to carbohydrates. Eighteen species of Antarctic marine algae have been tested for the presence of haemagglutinins against a several types of erythrocytes (rabbit, chicken, goat, sheep and ABO human blood groups). The protein extracts were prepared in phosphate buffered saline (PBS) pH 7.0. Serial doubling dilutions of extracts were prepared using 0.85% NaCl and an equal volume of 2% suspension of native or enzymatic treated erythrocytes was added to each tube, gentle mixed and left at 25 oC for 60 min before examination for agglutination. Fourteen species, among eighteen, produced haemagglutination of at least one type of blood cell tested. Protein extracts of three species were subjected to haemagglutination inhibition studies performed with a selection of sugars or glycoproteins. The activity of Adenocystis utriculares extracts was the only one inhibited by simple sugars. The other two extracts (Georgiella confluens and Gigartina skottsbergii) were not inhibited by mono- and polysaccharides, but were inhibited by glycoproteins.