Department of Green Chemistry and Technology, Laboratory of Chemical Analysis (LCA), Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Department of Biotechnology, Laboratory for Environmental Technology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Sci Rep. 2018 Jun 19;8(1):9325. doi: 10.1038/s41598-018-27540-9.
Numerous studies have investigated the antibacterial effect of both silver ions and silver nanomaterials on a large diversity of environmentally and clinically relevant bacteria. However, contradictory results are reported in which inhibition concentrations were varying by a 10-fold. This study investigated whether this variance in results could be attributed to the difference in experimental conditions, especially the microbial growth medium. B. subtilis was exposed to 500 µg L Ag in liquid growth media with different concentrations of some commonly used media components: tryptone, yeast extract, Cl, and S. The toxic effect was investigated by means of three complementary analysis techniques: (i) analyzing the growth curves obtained by optical density measurements, (ii) using flow cytometry, and (iii) by transmission electron microscopy. The silver ion toxicity towards B. subtilis decreased as more tryptone, yeast extract, or S was present. This study demonstrates that the medium composition, rarely acknowledged as an important experimental factor in bacterial toxicity studies, has a profound impact on the observed silver toxicity towards B. subtilis.
许多研究已经调查了银离子和银纳米材料对环境和临床相关细菌的抗菌作用。然而，报告的结果却存在矛盾，抑菌浓度相差 10 倍。本研究探讨了这种结果差异是否可以归因于实验条件的差异，特别是微生物生长培养基。枯草芽孢杆菌在含有不同浓度一些常用培养基成分（如胰蛋白胨、酵母提取物、Cl 和 S）的液体生长培养基中暴露于 500μg/L 的 Ag。通过三种互补的分析技术研究了毒性效应：（i）通过光密度测量分析获得的生长曲线，（ii）使用流式细胞术，和（iii）通过透射电子显微镜。枯草芽孢杆菌对银离子的毒性随着胰蛋白胨、酵母提取物或 S 的存在而降低。本研究表明，培养基组成很少被认为是细菌毒性研究中的一个重要实验因素，但它对观察到的枯草芽孢杆菌对银的毒性有深远的影响。
