Burkhart J G, Helgen J C, Fort D J, Gallagher K, Bowers D, Propst T L, Gernes M, Magner J, Shelby M D, Lucier G
National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA.
Environ Health Perspect. 1998 Dec;106(12):841-8. doi: 10.1289/ehp.106-1533234.
Water samples from several ponds in Minnesota were evaluated for their capacity to induce malformations in embryos of Xenopus laevis. The FETAX assay was used to assess the occurrence of malformations following a 96-hr period of exposure to water samples. These studies were conducted following reports of high incidences of malformation in natural populations of frogs in Minnesota wetlands. The purpose of these studies was to determine if a biologically active agent(s) was present in the waters and could be detected using the FETAX assay. Water samples from ponds with high incidences of frog malformations (affected sites), along with water samples from ponds with unaffected frog populations (reference sites), were studied. Initial experiments clearly showed that water from affected sites induced mortality and malformation in Xenopus embryos, while water from reference sites had little or no effect. Induction of malformation was dose dependent and highly reproducible, both with stored samples and with samples taken at different times throughout the summer. The biological activity of the samples was reduced or eliminated when samples were passed through activated carbon. Limited evidence from these samples indicates that the causal factor(s) is not an infectious organism nor are ion concentrations or metals responsible for the effects observed. Results do indicate that the water matrix has a significant effect on the severity of toxicity. Based on the FETAX results and the occurrence of frog malformations observed in the field, these studies suggest that water in the affected sites contains one or more unknown agents that induce developmental abnormalities in Xenopus. These same factors may contribute to the increased incidence of malformation in native species.
对明尼苏达州多个池塘的水样进行了评估，以确定其诱导非洲爪蟾胚胎畸形的能力。使用FETAX试验评估暴露于水样96小时后畸形的发生率。这些研究是在明尼苏达州湿地青蛙自然种群中畸形发生率高的报告之后进行的。这些研究的目的是确定水中是否存在生物活性剂，并能否使用FETAX试验检测到。研究了青蛙畸形发生率高的池塘（受影响地点）的水样以及青蛙种群未受影响的池塘（参考地点）的水样。初步实验清楚地表明，受影响地点的水会导致非洲爪蟾胚胎死亡和畸形，而参考地点的水几乎没有影响或没有影响。畸形诱导呈剂量依赖性，并且在储存样本以及整个夏季不同时间采集的样本中都具有高度可重复性。当样本通过活性炭时，样本的生物活性降低或消除。这些样本的有限证据表明，致病因素不是传染性生物体，离子浓度或金属也不是观察到的影响的原因。结果确实表明水基质对毒性严重程度有显著影响。基于FETAX结果和在野外观察到的青蛙畸形情况，这些研究表明，受影响地点的水中含有一种或多种未知物质，可诱导非洲爪蟾发育异常。这些相同的因素可能导致本地物种畸形发生率增加。
