Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106-9625, USA.
Nat Nanotechnol. 2011 Jan;6(1):65-71. doi: 10.1038/nnano.2010.251. Epub 2010 Dec 19.
Previous studies have shown that engineered nanomaterials can be transferred from prey to predator, but the ecological impacts of this are mostly unknown. In particular, it is not known if these materials can be biomagnified-a process in which higher concentrations of materials accumulate in organisms higher up in the food chain. Here, we show that bare CdSe quantum dots that have accumulated in Pseudomonas aeruginosa bacteria can be transferred to and biomagnified in the Tetrahymena thermophila protozoa that prey on the bacteria. Cadmium concentrations in the protozoa predator were approximately five times higher than their bacterial prey. Quantum-dot-treated bacteria were differentially toxic to the protozoa, in that they inhibited their own digestion in the protozoan food vacuoles. Because the protozoa did not lyse, largely intact quantum dots remain available to higher trophic levels. The observed biomagnification from bacterial prey is significant because bacteria are at the base of environmental food webs. Our findings illustrate the potential for biomagnification as an ecological impact of nanomaterials.
先前的研究表明，工程纳米材料可以从被捕食者转移到捕食者，但这种转移对生态的影响在很大程度上是未知的。特别是，目前还不清楚这些材料是否可以生物放大——在这个过程中，食物链中较高位置的生物体积累了更高浓度的材料。在这里，我们表明，在铜绿假单胞菌细菌中积累的裸露的 CdSe 量子点可以转移到并在捕食细菌的嗜热四膜虫原生动物中生物放大。原生动物捕食者中的镉浓度比它们的细菌猎物大约高出五倍。经量子点处理的细菌对原生动物具有不同的毒性，因为它们在原生动物的食物泡中抑制了自身的消化。由于原生动物没有裂解，因此大量完整的量子点仍然可供更高营养级使用。从细菌猎物中观察到的生物放大是显著的，因为细菌处于环境食物网的基础。我们的研究结果说明了生物放大作为纳米材料的生态影响的可能性。
