Department of Biological Engineering, Utah State University, Logan, UT 84322, USA.
Environ Pollut. 2011 Jul;159(7):1749-56. doi: 10.1016/j.envpol.2011.04.020. Epub 2011 May 6.
The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells' periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.
将市售氧化铜和氧化锌纳米颗粒 (NPs) 的毒性与有益根际分离株假单胞菌氯化物 O6 进行了比较。在用于细菌暴露的条件下，NPs 聚集并不同程度地释放离子，并与细菌细胞表面结合。细菌表面电荷被 NPs 中和，这取决于 pH 值。氧化铜 NPs 比氧化锌 NPs 更具毒性。Cu 离子但不是氧化铜 NPs 降低了细胞外聚合物物质 (EPS) 胶体的负表面电荷；EPS 保护细胞免受氧化铜 NPs 的毒性。Cu 离子螯合剂消除了氧化铜 NPs 的毒性，表明离子释放参与其中。NPs 均未从细胞周质中释放碱性磷酸酶，表明外膜损伤最小。细胞内活性氧物质的积累与氧化铜 NPs 的致死性相关。NPs 的环境沉积可能会为离子释放创造小生境，从而对易感土壤微生物产生影响。
