Department of Biology and Microbiology, University of Wisconsin Oshkosh, Oshkosh, WI, USA.
Lett Appl Microbiol. 2014 Apr;58(4):330-7. doi: 10.1111/lam.12205. Epub 2013 Dec 18.
Polycyclic aromatic hydrocarbons (PAH) are a common environmental contaminant originating from both anthropogenic and natural sources. Mycobacterium species are highly adapted to utilizing a variety of PAH. Silver nanoparticles (AgNP) are an emerging contaminant that possess bactericidal properties, interferes with the bacterial membrane and alters function. Mycobacterium sp. strain RJGII-135 provided a model bacterium to assess changes in carbon metabolism by focusing on PAH degradation, which is dependent upon passive uptake of hydrophobic molecules into the cell membrane. A mixture of 18 PAH served as a complex mixture of carbon sources for assessing carbon metabolism. At environmentally relevant PAH concentrations, RJGII-135 degraded two-, three-, and four-ring PAH within 72 h, but preferentially attacked phenanthrene and fluorene. Total cell growth and PAH degradation were successively reduced when exposed to 0·05-0·5 mg 1(-1) AgNP. However, 0·05 mg l(-1) AgNP inhibited degradation of naphthalene, acenaphthylene and acenaphthalene. RJGII-135 retained the ability to degrade the methylated naphthalenes regardless of AgNP concentration suggesting that proteins involved in dihydrodiol formation were inhibited. The reduced PAH metabolism of RJGII-135 when exposed to sublethal concentrations of AgNP provides evidence that nanoparticle pollution could alter carbon cycling in soils, sediment and aquatic environments.
Silver nanoparticle (AgNP) pollution threatens bacterial-mediated processes due to their antibacterial properties. With the widespread commercial use of AgNP, continued environmental release is inevitable and we are just beginning to understand the potential environmental ramifications of nanoparticle pollution. This study examined AgNP inhibition of carbon metabolism through the polycyclic aromatic hydrocarbon degradation by Mycobacterium species RJGII-135. Sublethal doses altered PAH metabolism, which is dependent upon cell membrane properties and intracellular proteins. The changed carbon metabolism when exposed to sublethal doses of AgNP suggests broad impacts of this pollution on bacterial carbon cycling in diverse environments.
多环芳烃（PAH）是一种常见的环境污染物，来源于人为和自然来源。分枝杆菌属物种高度适应于利用各种 PAH。银纳米粒子（AgNP）是一种新兴的污染物，具有杀菌特性，干扰细菌膜并改变功能。分枝杆菌属菌株 RJGII-135 提供了一种模型细菌，通过专注于 PAH 降解来评估碳代谢的变化，PAH 降解依赖于疏水分子被动吸收到细胞膜中。18 种 PAH 的混合物作为评估碳代谢的复杂碳源混合物。在环境相关的 PAH 浓度下，RJGII-135 在 72 小时内降解了二、三、四环 PAH，但优先攻击菲和芴。当暴露于 0.05-0.5 mg l(-1) AgNP 时，总细胞生长和 PAH 降解相继减少。然而，0.05 mg l(-1) AgNP 抑制了萘、苊烯和苊的降解。RJGII-135 保留了降解甲基萘的能力，无论 AgNP 浓度如何，这表明参与二氢二醇形成的蛋白质受到抑制。当暴露于亚致死浓度的 AgNP 时，RJGII-135 的 PAH 代谢减少提供了证据，表明纳米颗粒污染可能改变土壤、沉积物和水生环境中的碳循环。
银纳米粒子（AgNP）污染由于其抗菌特性而威胁到细菌介导的过程。随着 AgNP 的广泛商业用途，持续的环境释放是不可避免的，我们才刚刚开始了解纳米颗粒污染的潜在环境影响。本研究通过分枝杆菌属 RJGII-135 对多环芳烃的降解来研究 AgNP 对碳代谢的抑制作用。亚致死剂量改变了 PAH 代谢，这取决于细胞膜特性和细胞内蛋白质。当暴露于亚致死剂量的 AgNP 时，碳代谢的变化表明这种污染对不同环境中细菌碳循环的广泛影响。
