INHIBITION OF BACTERIAL RESPIRATION BY A LOW-MOLECULAR-WEIGHT LECTIN,SCYLLIN, FROM SCYLLA-SERRATA CRAB HEMOLYMPH

Interaction of plant and/or invertebrate lectins with mammalian cells and different microorganisms is well known. In the present study, we h ave demonstrated that scyllin, a low molecular weight (MW 4000) lectin from the edible crab Scylla serrata hemolymph, purified by GalNAc-Sep haron affinity column followed by Mono-Q ion exchanger in FPLC exhibit s antimicrobial activity against Bacillus cereus and Escherichia coil by inhibiting endogenous respiration as well as exogenous glucose oxid ation. In both the cases oxygen consumption has been measured in an ox ygraph. Scyllin has produced 50% inhibition of endogenous respiration at a concentration of 110 mu g/ml and 125 mu g/ml in B. cereus and E. coli respectively. It also reduced the exogenous glucose oxidation by 50% at a concentration of 12 mu g/ml and 80 mu g/ml respectively in B. cereus and E. coil. From the above study the mechanism of bacterial g rowth inhibitory property of scyllin is suggested though the other stu dies such as inhibition of nucleic acid biosynthesis, cell wall biosyn thesis etc. to evaluate its total mode of inhibitory action are not ye t obtained.