Department of Zoology, Karnatak University, Dharwad-580 003, India.
J Appl Toxicol. 2010 Jul;30(5):431-6. doi: 10.1002/jat.1514.
Novaluron is an insect growth regulator (IGR) used against fruit-borers and domestic pests. In this study, effects of different concentrations (0.5, 0.75, 1.0, 1.5 microg l(-1)) of novaluron on the tail regeneration, limb development and metamorphosis were examined in Bufo melanostictus. Thyroxine (1.0, 2.0, 3.5, 5.0 microg l(-1)), which promotes amphibian development/metamorphosis, and vitamin A (5, 20, 40, 60 IU l(-1)), which disrupts development and induce polymelia, were used for comparison. Bufo melanostictus tadpoles were raised in the laboratory from eggs collected around Dharwad in August 2007. The tail of tadpoles was amputated at limb-bud stage under ether anesthesia. Ten tadpoles were exposed to each concentration of chemicals in triplicate for 5 days and then reared in conditioned water. Tadpoles were fed on boiled spinach. In controls (tadpoles exposed to ringer solution), the tail regenerated on the 5th day, hind-limbs and fore-limbs appeared on days 15 and 24, respectively; metamorphosis was complete on the 30th day. In 1 and 2 microg l(-1) thyroxine exposed tadpoles, regeneration of tail, development of limbs and metamorphosis were preponed to the 4th, 7th, 11th and 23rd day respectively. Exposure to vitamin A resulted in the regeneration of laterally drooped tails, delay in limb development and arrest of metamorphosis in all the concentrations used. Novaluron at lower dose (0.5 microg l(-1)) was not effective, but at 0.75 microg and higher concentrations it elicited results comparable to those of vitamin A. The study indicates that novaluron interferes with amphibian development if found as contaminant in the water bodies where amphibians live and reproduce.
哒螨灵是一种昆虫生长调节剂（IGR），用于防治蛀果虫和家庭害虫。本研究检测了哒螨灵在黑眶蟾蜍（Bufo melanostictus）尾再生、肢体发育和变态过程中的不同浓度（0.5、0.75、1.0、1.5μg l(-1)) 的作用。甲状腺素（1.0、2.0、3.5、5.0μg l(-1))，可促进两栖动物的发育/变态，维生素 A（5、20、40、60IU l(-1))，可破坏发育并导致多指畸形，被用作比较。黑眶蟾蜍蝌蚪于 2007 年 8 月从达瓦尔采集的卵在实验室中饲养。在乙醚麻醉下，将肢芽期的蝌蚪尾巴截断。10 只蝌蚪被暴露于每种浓度的化学物质中，重复 3 次，持续 5 天，然后在条件水中饲养。蝌蚪以煮熟的菠菜为食。在对照组（暴露于林格氏液的蝌蚪）中，尾巴在第 5 天再生，后肢和前肢分别在第 15 天和第 24 天出现；第 30 天完全变态。在 1 和 2μg l(-1)甲状腺素暴露的蝌蚪中，尾巴再生、肢体发育和变态分别提前到第 4、7、11 和 23 天。维生素 A 的暴露导致尾巴横向下垂的再生、肢体发育延迟和所有使用浓度的变态停止。较低剂量（0.5μg l(-1))的哒螨灵无效，但在 0.75μg 及更高浓度下，其效果与维生素 A 相当。该研究表明，如果哒螨灵作为污染物存在于两栖动物生活和繁殖的水体中，它会干扰两栖动物的发育。
