An intracellular toxic protein （Xin） isolated from Xenorhabdus nematophilus strain BJ

摘要

＜正＞ An intracellular toxic protein, designated Xin and with remarkable inhibitory effect on growth of Helicoverpa armiger-a, was isolated from X. nematophilus strain BJ by ion exchange chromatography and hydrophobic interaction chromatography. After placing neonates on the artificial diet containing Xin at concentration of 0 or 3.48 μg/g for 7 days, the average weight of insects was 23.50 mg and 0.55mg, respectively. The activity of Xin was lost by heating, freeze-drying, digestion with proteases or urea. The Xin molecular weight, over 1000 kD, was determined by gel filtration on Superose 12, and there were six component proteins analyzed by SDS-PAGE. The results show that Xin is a high molecular protein complex inhibiting growth of insect pest.