Pb2+、Cd2+混合添食对家蚕生长发育及细胞凋亡的影响

家蚕自3龄起添食单一和混合的Cd2+、Pb2+重金属溶液,观察并记录其生长发育状况,测量各时期体长,提取DNA并分析断裂情况。结果表明,添食Pb2+、Cd2+两种混合重金属离子的家蚕体型比单一添食相应含量Cd2+的大,其体长大于单一添食相同含量Pb2+、Cd2+的家蚕;单一重金属离子作用下的家蚕DNA发生明显的梯状断裂,出现细胞凋亡现象,而混合重金属诱导的家蚕细胞DNA完整,未发生凋亡现象,预示着竞争位点假说在家蚕体内的存在。

Effect of Silkworm Fed on Mixture of Pb2+ and Cd2+ on its Development and Inducement of Apoptosis

The growth and development state and DNA disruption of silkworm,fed on the mulberry leaves treated with Pb~(2 ),Cd~(2 ) or mixture of them since the 3~(rd) instar,were investigated.The results showed that the body figure and length of silkworm fed on the mixture were larer and longer than those of silkworm fed on Pb~(2 ) or Cd~(2 ).The electrophoresis results of DNA from haemolymph indicated that specific DNA bands appeared clearly and regularly for silkworms fed on Pb~(2 ) or Cd~(2 ),but for silkworms fed on the mixture.This suggested that there existed the apoptosis only in haemolymph of silkworms fed on Pb~(2 ) or Cd~(2 ).The above results suggested that the hypothesis of rivalship among heavy metal ions existed in the silkworm.