氟化物对家蚕耐氟和氟化物敏感品种幼虫中肠羧酸酯酶及全酯酶活性的影响

为了探讨氟化物在家蚕Bombyx mori体内的代谢途径， 以家蚕耐氟品种T6和氟化物敏感品种734为研究材料， 在5龄幼虫1-7 d内分别添食经50， 100， 200和400 mg/kg NaF溶液浸泡后的新鲜桑叶， 检测家蚕中肠羧酸酯酶（CarE）和全酯酶活性的变化。结果表明： 734添氟组的CarE活性是对照组的1.21~1.98倍， 而T6添氟组约是对照组的0.72~1.10倍。734和T6添氟组的全酯酶活性数值变化规律与其各自对照组相似， 且2品种之间的酶活性数值很相近。2品种在相同浓度下， 不同天数之间的全酯酶活性差异均显著（P＜0.05）。推测氟化物对敏感家蚕中肠CarE有促进作用， 对耐氟家蚕中肠CarE有抑制作用， 但是对全酯酶活性影响不大。

Influence of fluoride on activities of carboxylesterases and esterases in the larval midgut of the fluoride-resistant and susceptible strains of Bombyx mori

To explore the metabolic pathway of NaF in the silkworm, Bombyx mori, the 5th instar larvae of the fluoride-resistant silkworm strain (T6) and the fluoride-susceptible strain (734) were fed on mulberry leaves soaked in 50, 100, 200 and 400 mg/kg NaF solutions, respectively, for 1-7 d, and the activities of carboxylesterases (CarE) and esterases in the midgut were examined. The results showed that the CarE activity in strain 734 was 1.21-1.98-fold as high as that in the control group, while the CarE activity in strain T6 was 0.72-1.10-fold as high as that in the control group. In both strains treated with NaF, the change trend of the esterase activity was similar with the control group within 7 d, and the esterase activity in the two strains was also similar. When the two silkworm strains were treated by NaF at the same concentration, their esterase activities on different days after treatment were significantly different （P＜0.05）. It is inferred that fluoride can increase the CarE activity in the midgut of the fluoride-susceptible strain of the silkworm, and inhibit the CarE activity in the midgut of the fluoride-resistant strain, but it has little effect on the esterase activity in the midgut of both strains of the silkworm.