Bt转基因水稻米粉对家蚕生长发育及中肠亚显微结构的影响

The Effect of Bt Transgenic Rice Flour on the Development of Silkworm Larvae and the Sub-micro-structure of Its Midgut

以 3龄家蚕为供食对象 ,用洒过转苏云金杆菌 (Bacillusthuringiensis,Bt)基因水稻纯合品系KMD2生米粉或熟米粉的桑叶喂养 ,研究Bt抗虫水稻稻米对家蚕生长发育及中肠亚显微结构的影响 ,以明确生米粉与熟米粉之间的差异。结果发现 ,用前者喂养的家蚕体重、熟蚕数、结茧数、全茧量和茧层量均明显低于后者和对照 ,熟蚕整齐度明显迟于后者和对照 ;而后者与对照之间无明显差异。进一步的病理切片电镜分析表明 ,用前者喂养的家蚕 ,其中肠细胞亚显微结构发生了明显的变化 ,杯形细胞和圆筒形细胞的微绒毛明显变短、变粗 ,线粒体和粗面型内质网的数量显著下降 ;而后者与对照之间无显著差异。由此表明 ,经蒸煮后Bt水稻稻米中的杀虫蛋白发生变性 ,失去活性 ,进而丧失致毒能力。

This study was conducted on the influence of Bt transgenic rice raw flour containing cry1Ab gene on the development of silkworm larvae. Contrary with normal treat, the larvae mortality of silkworm in either Bt transgenic rice raw flour treat or Bt transgenic rice cooked flour treat, was not significantly different. The variances in weight of silkworm larvae, the number of grown silkworm, the number of cocoons, the weight of cocoons and cocoon layers at different periods were significant at 0.01 level. In addition, the sub micro structure of midgut of silkworm larvae in Bt transgenic rice raw flour treat changed clearly via pathological analysis. Micro down of midgut cells became shorter and thicker. The number of mitochondrion and rough endoplasmic reticulum reduced significantly. No significant differences(P>0.05) were observed in the above aspects between Bt transgenic rice cooked flour treat and the controls. Therefore, Bt transgenic rice lost the toxicity capacity due to the denaturation of Bt toxin protein after cooking.