Purification And Anti-Aphid Effect Of An Acidic Agglutinin From Winged Bead (WBAâ…¡)

An acidic agglutinin (WBAⅡ), which showed strong hemagglutination effect on rabbit red blood cells(RBCs), was purified from seeds of winged bean(Psophocarpus tetragonolobus) by a procedure including precipitated by ammonium sulphate, DEAE-52 iron-exchange and Sephadex G-100 gel filtration. The purified WBA H gave a single band on PAGE suggesting the purity of the preparation. The result of pH on the agglutinating activity of WBAⅡshowed that its stability spanned at pH 3.0-10.0. The agglutininwas stable up to 60℃. Its activity gradually decreased with further increase in temperature, it was completely inactive upon heat treatment at 90℃. In 4mol/L urea the agglutinating activity of WBAⅡvanished.Anti-aphid Effect of WBAⅡand action mechanism were also studied. The result showed that WBAⅡinhibited the honeydew secretion, reproductive rate and inhibition rate of gowth towards aphid. And it also had repellent action and stomach toxic to the insect. The insect was treated with 2％crude WBAⅡand the inhibition rate of honeydew secretion were 30.00％,41.67％after 1day and 2days. The percent of eating and setting down were 16％,14％,6％after 24 hours, 48hours and 72hours. The mortality reached 54％,82％and one adult layed 0.01,0.04,0.04,0.04 aphid averagely after 2 days, 3 days, 4 days and 5 days. The inhibition rate of growth were 26.09％,28.04％,39.23％,52.62％after 2days, 3days, 4days and 5 days.The insect was treated with 0.25％chromatographic purification sample of WBAⅡthe inhibition rate of honeydew secretion were 57.62％,61.67％after lday and 2days. The percent of eating and setting down were 26％,20％,6％after 24 hours, 48hours and 72hours. The mortality reached 54％,82％and one adult layed 0.08,0.28,0.24,0.14 aphid averagely after 2 days, 3 days, 4 days and 5 days. The inhibition rate of growth were 27.94％,44.46％,66.16％,71.14％after 2days, 3days, 4days and 5 days. After aphid were treated with purification sample had some effects on the glycogen and the protein content in the insect body. The actives of digesting proteinase and digesting amylase were both inhibited in vivro.