苏云金芽胞杆菌晶体毒素对体外培养的日本血吸虫童虫的作用

Efficacy of Crystal Toxin of Bacillus thuringiensis against Schistosomula of Schistosoma japonicum in vitro

将感染日本血吸虫的钉螺常规逸蚴，经注射器推压机械断尾获得的童虫，加入内含１０％兔血清的ＲＰＭＩ－１６４０培养液后，置于单克隆培养板内，以苏云金芽胞杆菌（菌株ＹＢＴ－１９５５）制得的伴胞晶体毒素，以不同的浓度加入以上各孔中于３７℃，５％ＣＯ２培养箱内培养。培养１２ｈ后发现童虫活动力减弱，有些已经死亡；２４ｈ后，随着加入伴胞晶体毒素浓度的增加，童虫死亡率也相应增加，呈正相关（ｒ＝０．８９７）。经毒素蛋白含量为４０ｍｇ／Ｌ处理的童虫，２４ｈ后死亡率为１００％，ＬＤ５０为１５．９５μｇ（１ｍＬ）。

The schistosomula of Schistosoma japonicum were transformed from cercariae released from the snails by syringe method and incubated in the RPMI 1640 medium, which contained 10% rabbit serum and maintained in monoclonal culture plate. Different densities of crystal toxin from the Bacillus thuringiensis (Strain YBT 1955), were added separately in the hole of plate and incubated at 37℃, 5% CO 2. The activity of the schistosomula became low and some of the worms died after being incubated for 12 h as observed under microscope. The mortality of the schistosomula incresed with the density of crystal toxin showing a positive correlation (r=0.897). Treatment of schistosomula with 40 μg total protein (1 mL) of toxin yielded 100% mortality after 24 h in vitro. The LD 50 value was 15.95 μg total protein(1 mL).