Effects of ultraviolet light and methoprene on survival and development of Rana pipiens
Effects of ultraviolet light and methoprene on survival and development of Rana pipiens
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DOI：
10.1002/etc.5620171222
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发表时间：
1998-12-01
影响因子：
4.1
通讯作者：
Diamond, SA
中科院分区：
文献类型：
--
作者：
Ankley, GT;Tietge, JE;Diamond, SA
最近，在北美的几种无尾两栖动物身上观察到了一组相对特殊的后肢畸形。这些畸形包括异位和多余的四肢，以及缺失的四肢、四肢节段或手指。这项研究的目的是评估两种被假设为导致两栖动物肢体畸形的应激源：甲氧基丁二烯，一种昆虫生长调节剂，通过与维甲酸信号系统的相互作用，可能导致肢体畸形；以及紫外线。在没有和存在紫外光的情况下，北豹蛙(林蛙)都被暴露在几种不同浓度的甲基丁二烯中，以模拟阳光中存在的紫外线波长光谱。暴露开始于早期胚胎阶段(新受精卵)，并持续到青蛙前肢的出现。在测试的最高浓度下，无论是在没有紫外光的情况下，还是在存在紫外光的情况下，都观察到了严重的发育影响，所有的生物都在试验开始后的12到16天内死亡。然而，接触这种杀虫剂并没有导致肢体畸形。不考虑甲氧基丁二烯的治疗，在紫外线照射下24天的动物中，有很高的百分比(接近50%)会出现后肢畸形。这些畸形通常是双侧的，有时是完全对称的，由缺失的肢体节段和缺失或减少的手指组成。出现了完整的近端和远端的缺陷，从股骨缺失或畸形到缺少单指或指节段。对紫外光最敏感的发育期出现在瓣芽发育的非常早期，与顶端外胚层脊的形成相对应。这些发现对Hold中的变形青蛙的意义尚不确定。虽然观察到的畸形类型(即缺失的肢体节段和脚趾)与在一些野外标本中看到的相似，但紫外线治疗并不会导致在野外观察到的动物的全部畸形(例如，多出的肢体、非双侧畸形)。此外，尽管利用的人造光谱模仿了阳光中存在的相对紫外线光谱，但它不能完全匹配阳光强度，也不能准确地模仿可见光波长。最后，实验室中使用的紫外光剂量与野外两栖动物实际经历的紫外光剂量之间的关系尚不确定。尽管存在这些问题，但我们的发现表明，紫外线应该进一步被认为是导致野外环境中两栖动物畸形的一个合理因素。
Recently a suite of relatively specific hindlimb deformities have been observed in several anuran species in North America. These deformities include ectopic and supernumerary limbs and missing limbs, limb segments, or digits. The objective of this study was to assess two stressors hypothesized as responsible for limb malformations in amphibians: methoprene, an insect growth regulator that, through interaction with the retinoic acid signaling system, could possibly cause limb deformities, and ultraviolet (UV) light. Northern leopard frogs (Rana pipiens) were exposed to several different concentrations of methoprene both in the absence and presence of UV light designed to mimic the UV wavelength spectrum present in sunlight. Exposures were initiated at early embryonic stages (newly fertilized eggs) and continued through emergence of the forelimbs of the frogs. At the highest methoprene concentration tested, both in the absence and presence of UV light, severe developmental effects were observed, with all organisms dying within 12 to 16 d of test initiation. However, exposure to the pesticide did not cause limb malformations. Irrespective of methoprene treatment, a very high percentage (similar to 50%) of animals held under the UV light for 24 d developed hindlimb malformations. These malformations usually were bilateral and sometimes completely symmetrical, and consisted of missing limb segments and missing or reduced digits. A complete proximal to distal representation of the deficiencies occurred, ranging from missing or malformed femurs to the absence of single digits or digit segments. The developmental period of greatest sensitivity to UV light occurred during very early limb bud development, corresponding with formation of the apical ectodermal ridge. The significance of these findings in terms of deformed frogs in the held is uncertain. Although the deformity types observed (i.e., missing limb segments and digits) were similar to those seen in some field specimens, the UV light treatment did not cause the full range of malformations observed in animals from the field (e.g., supernumerary limbs, nonbilateral deformities). Furthermore, although the artificial light spectrum utilized mimicked the relative UV spectrum present in sunlight, it did not match full sunlight intensity, and did not accurately mimic visible wavelengths. Finally, the relationship of the UV light dose used in the laboratory to that actually experienced by amphibians in the field is uncertain. Despite these questions, our findings suggest that UV light should be further considered as a plausible factor contributing to amphibian malformations in field settings.