Dhas Sindhu Priya, Shiny Punalur John, Khan Sudheer, Mukherjee Amitava, Chandrasekaran Natrajan
Centre for Nanobiotechnology, VIT University, Tamil Nadu, India.
J Basic Microbiol. 2014 Sep;54(9):916-27. doi: 10.1002/jobm.201200316. Epub 2013 Mar 1.
Silver and zinc oxide nanoparticles (Ag and ZnO NPs) are widely used as antimicrobial agents. However, their potential toxicological impact on environmental microorganisms is largely unexplored. The aim of this work was to investigate the sensitivity and adaptability of five bacterial species isolated from sewage towards Ag and ZnO NPs. The bacterial species were exposed to increasing concentration of nanoparticles and the growth inhibitory effect, exopolysaccharides (EPSs) and extracellular proteins (ECPs) productions were determined. The involvement of surface charge in nanoparticles toxicity was also determined. The bacterial species were constantly exposed to nanoparticles to determine the adaptation behavior toward nanoparticles. The nanoparticles exhibited remarkable growth inhibitory effect on tested bacterial species. The toxicity of nanoparticles was found to be strongly dependent on surface charge effects. Though, these organisms are highly sensitive to Ag and ZnO NPs, the continuous exposure to these nanoparticles leads to moderate adaptation of bacterial species and the adapted bacterial species convert the highly toxic nano form to less toxic microform. Finally we predict that the continuing applications of nanoparticles in consumer products may lead to the development of nanoparticles resistant bacterial strains in future.
银和氧化锌纳米颗粒（Ag和ZnO NPs）被广泛用作抗菌剂。然而，它们对环境微生物潜在的毒理学影响在很大程度上尚未得到探索。这项工作的目的是研究从污水中分离出的五种细菌对Ag和ZnO NPs的敏感性和适应性。将这些细菌暴露于浓度不断增加的纳米颗粒中，并测定生长抑制作用、胞外多糖（EPSs）和胞外蛋白（ECPs）的产生。还测定了表面电荷在纳米颗粒毒性中的作用。持续让细菌暴露于纳米颗粒中，以确定其对纳米颗粒的适应行为。纳米颗粒对受试细菌表现出显著的生长抑制作用。发现纳米颗粒的毒性强烈依赖于表面电荷效应。虽然这些生物体对Ag和ZnO NPs高度敏感，但持续暴露于这些纳米颗粒会导致细菌适度适应，并且适应后的细菌会将高毒性的纳米形式转化为低毒性的微形式。最后，我们预测纳米颗粒在消费品中的持续应用可能会导致未来产生抗纳米颗粒的细菌菌株。
