Greulich K, Pflugmacher S
Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Biochemical Regulation, Müggelseedamm 301, 12587 Berlin, Germany.
Arch Environ Contam Toxicol. 2004 Nov;47(4):489-95. doi: 10.1007/s00244-004-2302-3.
A number of factors have been suggested for recently observed amphibian decreases, and one potential factor is pesticide exposure. We studied the uptake and effects of environmentally relevant concentrations of the pyrethroid insecticide cypermethrin on two different amphibian species, Bombina variegata and Rana arvalis. The uptake from water of 14C-labeled cypermethrin (0.4 microg/L) by eggs and tadpoles of B. variegata was investigated. After 24 hours of exposure, 153.9 ng cypermethrin/g fresh weight were found in embryos, thus indicating that the jelly mass of the eggs does not act as a sufficient physical barrier to protect embryos from exposure to this compound. Uptake of cypermethrin into tadpoles of both species and in all exposed individuals caused dose-dependent deformities; behavioral abnormalities such as twisting, writhing, and coordinated swimming; and mortality. In tadpoles of B. variegata and R. arvalis, the activity of microsomal and cytosolic glutathione S-transferase (mGST and sGST, respectively) were measured after treatment with cypermethrin. Activities of both GST systems increased significantly with increasing duration and concentration of cypermethrin exposure, with the reaction seeming stronger in B. variegata than in R. arvalis tadpoles. Alpha-cypermethrin--a racemic mixture of two cis isomers of cypermethrin--induced a stronger enzymatic response in the cytosolic fraction of R. arvalis tadpoles than cypermethrin at the same concentration. The observed physical and behavioral abnormities caused by environmentally relevant concentrations of cypermethrin indicate that despite detoxication of the chemical via GST-system contamination of ponds by cypermethrin could result in adverse effects on the development of amphibian embryos and tadpoles.
对于近期观察到的两栖动物数量减少，人们提出了许多因素，其中一个潜在因素是接触杀虫剂。我们研究了环境相关浓度的拟除虫菊酯类杀虫剂氯氰菊酯对两种不同两栖动物物种——花背蟾蜍（Bombina variegata）和林蛙（Rana arvalis）的吸收及影响。研究了花背蟾蜍的卵和蝌蚪对14C标记的氯氰菊酯（0.4微克/升）从水中的吸收情况。暴露24小时后，在胚胎中发现每克鲜重含有153.9纳克氯氰菊酯，这表明卵的胶状物质并不能充分起到物理屏障的作用，以保护胚胎免受这种化合物的侵害。两种物种的蝌蚪对氯氰菊酯的吸收以及所有暴露个体都出现了剂量依赖性畸形；出现了诸如扭曲、扭动和协调游泳等行为异常；以及死亡情况。在用氯氰菊酯处理后，测定了花背蟾蜍和林蛙蝌蚪体内微粒体和胞质谷胱甘肽S-转移酶（分别为mGST和sGST）的活性。随着氯氰菊酯暴露时间和浓度的增加，两种谷胱甘肽S-转移酶系统的活性均显著增加，花背蟾蜍蝌蚪中的反应似乎比林蛙蝌蚪更强。α-氯氰菊酯——氯氰菊酯的两种顺式异构体的外消旋混合物——在相同浓度下，在林蛙蝌蚪的胞质部分诱导的酶促反应比氯氰菊酯更强。环境相关浓度的氯氰菊酯所导致的观察到的身体和行为异常表明，尽管通过谷胱甘肽S-转移酶系统对该化学物质进行了解毒，但氯氰菊酯对池塘的污染仍可能对两栖动物胚胎和蝌蚪的发育产生不利影响。
