Department of Environmental Chemistry, IDÆA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
Aquat Toxicol. 2012 Mar;109:100-10. doi: 10.1016/j.aquatox.2011.12.003. Epub 2011 Dec 13.
Risk assessment of emerging pollutants requires the development of bioassays able to detect and understand novel mechanisms of action. This study tested the hypothesis that the increase of offspring production in Daphnia magna induced by certain pollutants may be mediated through different mechanisms, depending on development stages, clones and food rations The study included two selective serotonin reuptake inhibitors (SSRIs), fluoxetine and fluvoxamine, and the detergent metabolite 4-nonylphenol. Organisms were exposed from birth to adulthood or only during adulthood at low and high food ration levels. Results indicated that low exposure levels of the three studied substances increased offspring production and/or juvenile developmental rates similarly for all studied clones, but the responses differed among life-stages and food rations. When individuals were exposed to the studied chemicals from birth, enhanced offspring production per female was observed only at low and intermediate food rations. On the contrary, when exposures started in gravid females most treatments increased offspring production. Results obtained with SSRIs support previous findings, where it was stated that these compounds may amplify serotoninergic signaling in D. magna. Nonylphenol effects may be related to the reported alteration of this compound in Daphnia ecdysteroid metabolism. Further investigations are necessary to resolve the biochemical mechanism of SSRI and nonylphenol enhancing offspring production.
新兴污染物的风险评估需要开发能够检测和理解新型作用机制的生物测定法。本研究检验了这样一个假设，即某些污染物诱导的大型溞后代产量增加可能通过不同的机制介导，这取决于发育阶段、克隆和食物配给。该研究包括两种选择性 5-羟色胺再摄取抑制剂（SSRIs），氟西汀和氟伏沙明，以及洗涤剂代谢物 4-壬基酚。从出生到成年或仅在成年期，在低和高食物配给水平下对生物体进行暴露。结果表明，三种研究物质的低暴露水平同样增加了所有研究克隆的后代产量和/或幼体发育速度，但在生命阶段和食物配给之间存在差异。当个体从出生开始接触研究中的化学物质时，仅在低和中等食物配给下观察到每个雌性增加的后代产量。相反，当在怀孕的雌性中开始暴露时，大多数处理都会增加后代的产量。SSRIs 的结果支持先前的发现，即这些化合物可能会放大大型溞中的血清素信号。壬基酚的作用可能与该化合物在溞类蜕皮激素代谢中的报道改变有关。需要进一步的调查来解决 SSRI 和壬基酚增强后代产量的生化机制。
