Characteristics of serum agglutinins in marine crab Scylla serrata Forskal and their interaction with various bacteria species

Abstract

Agglutinins or lectins are conventionally defined as proteins/glycoproteins of non immune origin with a remarkable ability to specifically and reversibly interact with carbohydrate ligands. Although lectins are produced by a myriad of organisms, some of which are phylogenetically remote, and therefore exhibit distinct physicochemical and biochemical characteristics, lectins from different sources may essentially exhibit common biological activities. This study was therefore undertaken to preliminarily characterize the lectins in the serum of S. serrata as a prerequisite for isolation, purification and biological activity evaluation. Multiple agglutinins were detected in the serum of the marine crab Scylla serrata. The serum agglutinins agglutinated a wide range of mammalian erythrocytes RBC . The hemagglutinating activity was high within a pH range of 7.0 to 8.5, and was dependent on divalent cations Ca2+ , Sr2+ & Mg 2+ , with preference for Ca2+ . An agglutinating activity independent of Ca2+ was also demonstrated, indicating the presence of heterogenous agglutinins .The serum HA activity was inhibited by a wide range of related and unrelated carbohydrates, suggesting the presence of multiple agglutinins. The serum agglutinins reacted/interacted with a variety of bacteria including the Vibrio species known to be the most frequent opportunistic pathogens of aquatic crustaceans

dependent; carbohydrates; glycoproteins; host defense