Unit of Microbiology, Belgian Nuclear Research Centre SCK·CEN, 2400 Mol, Belgium.
Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium.
Metallomics. 2019 Nov 1;11(11):1912-1924. doi: 10.1039/c9mt00123a. Epub 2019 Oct 14.
The uncontrolled and widespread use of (nano)silver compounds has led to the increased release of these compounds into the environment, raising concerns about their negative impact on ecosystems. Concomitantly, silver resistance determinants are widely spread among environmental and clinically relevant bacteria although the underlying mechanisms are not yet fully understood. We show that Cupriavidus metallidurans is able to adapt to toxic silver concentrations. However, none of the known silver resistance determinants present in C. metallidurans are involved in the adaptative response. Instead, increased silver resistance is achieved by the concerted action of a two-component system AgrR-AgrS, previously not associated with metal resistance, and two periplasmic proteins PrsQ and PrsQ. Both proteins belong to an unique group of small, uncharacterized, secreted proteins restricted to the genera Cupriavidus and Ralstonia. This system gives C. metallidurans the ability to withstand much higher silver concentrations. The latter could be facilitated by the accumulation of silver ions and the formation of silver nanoparticles.
（纳米）银化合物的不受控制和广泛使用导致这些化合物越来越多地释放到环境中，引起了对它们对生态系统的负面影响的担忧。同时，尽管其潜在机制尚不完全清楚，但银抗性决定因子在环境和临床相关细菌中广泛传播。我们表明，金属硫杆菌能够适应有毒的银浓度。然而，金属硫杆菌中存在的任何已知的银抗性决定因子都没有参与适应性反应。相反，通过以前与金属抗性无关的双组分系统 AgrR-AgrS 和两个周质蛋白 PrsQ 和 PrsQ 的协同作用来实现增加的银抗性。这两种蛋白都属于一个独特的小而未被表征的分泌蛋白群，仅局限于铜绿假单胞菌属和罗尔斯顿氏菌属。该系统使金属硫杆菌能够承受更高的银浓度。这可能是通过银离子的积累和银纳米粒子的形成来促进的。
