Toxic effects of silver nanoparticles (Ag NPs) are, in most cases, measured within a single generation, while information regarding multigenerational exposure remains scarce. The current study assessed changes in toxic response (reproduction, fertility, and development) towards Ag NPs (NM300K; uncoated, 16.7 ± 6.5 nm) compared to AgNO3 over six generations, following chronic exposure of the model organism Caenorhabditis elegans. This revealed that AgNO3 exposure was associated with no changes in susceptibility to Ag. In contrast, multigenerational exposure to sub-lethal concentrations of Ag NPs resulted in persistent delayed development, but rendered increased tolerance to Ag NP with respect to fertility and fecundity. The results thus permit inference of a difference in toxic mode of action of the two forms of Ag, which instigate different response patterns. Results reveal a novel mechanism for the adaptation toward Ag NPs, where increased reproductive fitness occurs at the expense of somatic growth. This adaptive mechanism was, however associated with increased susceptibility to AgNO3 with respect to growth, fertility and reproduction. The current study thus demonstrates that a nano-specific resistance can be developed by C. elegans. Importantly, this adaptation renders increased vulnerability to another environmental stressor, and thus exposure to a second contaminant could be detrimental to such populations.

中文翻译：

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线虫秀丽隐杆线虫对多代银纳米颗粒（NM300K）暴露的适应性耐受性与对AgNO3的敏感性增加有关。

在大多数情况下，银纳米颗粒（Ag NPs）的毒性作用是在单代内测量的，而有关多代暴露的信息仍然很少。本研究评估了模型生物秀丽隐杆线虫的长期暴露后，与AgNO3相比，对Ag NPs（NM300K; 16.7±6.5 nm无涂层）的毒性反应（繁殖，繁殖力和发育）的变化在六代内的变化。这表明AgNO3暴露与对Ag的敏感性没有变化有关。相反，多代暴露于亚致死浓度的Ag NPs导致持续的发育延迟，但在生育力和繁殖力方面提高了对Ag NP的耐受性。因此，结果可以推断出两种形式的银在毒性作用方式上的差异，会引发不同的响应模式。结果揭示了一种针对Ag NPs适应的新机制，其中增加了生殖适应性而以体细胞生长为代价。但是，这种适应性机制在生长，繁殖力和繁殖方面与对AgNO3的敏感性增加有关。因此，当前的研究表明秀丽隐杆线虫可以产生纳米特异性电阻。重要的是，这种适应使另一个环境压力源的脆弱性增加，因此暴露于第二种污染物可能对这类人群有害。然而，与AgNO3在生长，繁殖力和繁殖方面的敏感性增加有关。因此，当前的研究表明秀丽隐杆线虫可以产生纳米特异性电阻。重要的是，这种适应使另一个环境压力源的脆弱性增加，因此暴露于第二种污染物可能对这类人群有害。然而，与AgNO3在生长，繁殖力和繁殖方面的敏感性增加有关。因此，当前的研究表明秀丽隐杆线虫可以产生纳米特异性电阻。重要的是，这种适应使另一个环境压力源的脆弱性增加，因此暴露于第二种污染物可能对这类人群有害。