Isolation, Characterization, and biological significance of a novel C-type marine lectin purified from Scylla serrata haemolymph

Marine lectins are unique glycoproteins that induce non-specific immunity in fishes and crustaceans. Mud crab Scylla serrata is highly abundant globally and rare, especially in Southeast Asian countries for its economic value. However, the characterisation of the c-type specific lectins is still not explored properly. In this current study, a novel c-type mannose-binding lectin was isolated from the marine crab Scylla serrata haemolymph using affinity chromatography. The purified lectin (Ss-Lec) of a 71kDa showed haemagglutination activity at the lowest concentration, and its homogenous and crystalline nature was evaluated by the HPLC, XRD, FTIR, and MALDI-TOF analysis. Moreover, the Ss-Lec depends on optimum pH, temperature, and calcium chelators. for its improved bioactivity. The purified Ss-Lec showed extensive antimicrobial properties against the important pathogenic aquatic bacteria Streptococcus iniae, Streptococcus agalactiae, Edwardsiella tarda, and, Aeromonas veronii at a concentration of 25-100µg/ml. This highly potential lectin can be further utilized against pathogenic diseases in aquaculture.