College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China; Department of Biotechnology, Shaheed Benazir Bhutto University, Sheringal, KPK, Pakistan.
College of Life Science and Technology, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China.
Chemosphere. 2019 Jan;215:693-702. doi: 10.1016/j.chemosphere.2018.10.091. Epub 2018 Oct 16.
Ionic silver is a potential hazard to aquatic life forms because of the increasing usage of silver based materials. The need for developing a sustainable and ecofriendly process to minimize the toxic effects of the free ions burden is now a scientific consensus. Therefore, we report the latest results in cyanobacterium Leptolyngbya JSC-1 investigating the tolerance towards toxic doses of silver, its extracellular biomineralization and silver nano-deposits formation inside the cells, and speculate about potential environmental impacts. In this study, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analysis reveal the extracellular biomineralization of soluble silver (1-100 μM) into corresponding nanoparticles (50-100 nm in diameter) by JSC-1, while X-ray photoelectron spectroscopy (XPS) examination divulged the presence of both Ag and Ag in extracellularly biomineralized silver, depicting a mixture of both AgO and elemental Ag. The scanning transmission electron microscopy (STEM), EDS and elemental mapping visualized the formation of intracellular silver nanoparticles. Moreover, this feature of silver tolerance in JSC-1 was further exploited and a novel protocol was developed for isolation and maintenance of axenic culture of this filamentous cyanobacterium. Consequently, this capability of silver biomineralization by JSC-1, both extra- and intra-cellularly might be useful for modeling the Ag resistance mechanism in cyanobacteria and also might be a sustainable alternative for heavy metals bioremediation in aquatic environments.
由于银基材料的使用越来越多，离子银对水生生物形态构成潜在危害。现在科学界已经达成共识，需要开发一种可持续和环保的工艺，以最大限度地减少游离离子的毒性影响。因此，我们报告了在蓝藻 Leptolyngbya JSC-1 中研究其对有毒剂量银的耐受性、其细胞外生物矿化作用以及细胞内银纳米沉积物形成的最新结果，并推测了其潜在的环境影响。在这项研究中，扫描电子显微镜（SEM）和能谱分析（EDS）揭示了 JSC-1 将可溶性银（1-100μM）生物矿化为相应的纳米颗粒（直径 50-100nm），而 X 射线光电子能谱（XPS）检测表明细胞外生物矿化的银中存在 Ag 和 Ag，描绘了 AgO 和元素 Ag 的混合物。扫描透射电子显微镜（STEM）、EDS 和元素映射可视化了细胞内银纳米颗粒的形成。此外，还进一步利用了 JSC-1 对银的耐受性，开发了一种分离和维持这种丝状蓝藻的无菌培养物的新方案。因此，JSC-1 具有的银生物矿化能力，无论是细胞内还是细胞外，都可能有助于模拟蓝藻中的 Ag 抗性机制，并且可能是水生环境中重金属生物修复的可持续替代方法。
