School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
Int J Mol Sci. 2020 Dec 22;22(1):15. doi: 10.3390/ijms22010015.
There is increasing recognition that environmental nano-biological interactions in model species, and the resulting effects on progeny, are of paramount importance for nanomaterial (NM) risk assessment. In this work, Daphnia magna F0 mothers were exposed to a range of silver and titanium dioxide NMs. The key biological life history traits (survival, growth and reproduction) of the F1 intergenerations, at the first (F1B1), third (F1B3) and fifth (F1B5) broods, were investigated. Furthermore, the F1 germlines of each of the three broods were investigated over 3 more generations (up to 25 days each) in continuous or removed-from NM exposure, to identify how the length of maternal exposure affects the resulting clonal broods. Our results show how daphnids respond to NM-induced stress, and how the maternal effects show trade-offs between growth, reproduction and survivorship. The F1B1 (and following germline) had the shortest F0 maternal exposure times to the NMs, and thus were the most sensitive showing reduced size and reproductive output. The F1B3 generation had a sub-chronic maternal exposure, whereas the F1B5 generation suffered chronic maternal exposure where (in most cases) the most compensatory adaptive effects were displayed in response to the prolonged NM exposure, including enhanced neonate output and reduced gene expression. Transgenerational responses of multiple germlines showed a direct link with maternal exposure time to 'sub-lethal' effect concentrations of NMs (identified from standard OECDs acute toxicity tests which chronically presented as lethal) including increased survival and production of males in the F1B3 and G1B5 germlines. This information may help to fine-tune environmental risk assessments of NMs and prediction of their impacts on environmental ecology.
人们越来越认识到，在模式物种中环境纳米生物学的相互作用以及由此对后代产生的影响，对于纳米材料（NM）风险评估至关重要。在这项工作中，用一系列银和二氧化钛 NM 对大型溞 F0 母体进行了暴露。在第一代（F1B1）、第三代（F1B3）和第五代（F1B5）幼虫中，研究了 F1 世代的关键生物生命周期特征（存活、生长和繁殖）。此外，还在连续或去除 NM 暴露的情况下，对每个三个幼虫种群的 F1 生殖系进行了 3 代以上的研究（每代 25 天），以确定母体暴露的长度如何影响克隆幼虫种群。我们的结果表明了溞类如何对 NM 诱导的应激做出反应，以及母体效应如何在生长、繁殖和存活率之间进行权衡。F1B1（和后续生殖系）接受 NM 诱导的应激的 F0 母体暴露时间最短，因此最敏感，表现出个体变小和繁殖力下降。F1B3 代经历了亚慢性母体暴露，而 F1B5 代则遭受了慢性母体暴露，在大多数情况下，对延长的 NM 暴露显示出最具补偿性的适应性效应，包括增强的幼体产量和降低的基因表达。多个生殖系的跨代反应与 NM 的“亚致死”效应浓度的母体暴露时间直接相关（通过标准 OECD 急性毒性测试确定，这些测试慢性呈现为致死性），包括 F1B3 和 G1B5 生殖系的存活率和雄性产量增加。这些信息可能有助于调整 NM 的环境风险评估，并预测它们对环境生态的影响。
