An Insight of the Naturally Occurring Agglutinins in a Few Species of Crabs and Characterization of the Agglutinin in the Crab Travancoriana charu

Three species of brachuran crabs were screened for the presence of agglutinins using mammalian erythrocytes as indicator cells. Hemagglutination assay results showed that the hemolymph of the freshwater crabs Travancoriana charu (Bahir and Yeo, 2007) and Oziotelphusa cf. hippocastanum (Muller, 1887) showed the highest HA titer with dog and buffalo erythrocytes respectively. The hemolymph of the marine crab Menippe rumphii (Fabricius, 1798) agglutinated with great avidity rat, mice and buffalo erythrocytes. Among the various tissues of Travancoriana charu analyzed for the presence of agglutinins, hemagglutination activity was observed in the hemolymph greater than hepatopancreas greater than muscles with rat and mice erythrocytes. HA was determined for both male and female crabs of Travancoriana charu ranging in size from 2.5-5 cm (weight 9.1-40 g). Hemagglutinating activity increased with increase in animal size and very significantly in the female crabs. Biochemical factors like water, protein and calcium content of the hemolymph did not have any conspicuous influence on the HA titer.