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The Antimicrobial Properties of Silver Nanoparticles in Bacillus subtilis Are Mediated by Released Ag+ Ions.
Hsueh, Yi-Huang; Lin, Kuen-Song; Ke, Wan-Ju; Hsieh, Chien-Te; Chiang, Chao-Lung; Tzou, Dong-Ying; Liu, Shih-Tung.
  • Hsueh YH; Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan, Taiwan.
  • Lin KS; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
  • Ke WJ; Graduate Institute of Biomedical Sciences, and Research Center for Bacterial Pathogenesis, Chang Gung University, Taoyuan, Taiwan.
  • Hsieh CT; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
  • Chiang CL; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
  • Tzou DY; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
  • Liu ST; Graduate Institute of Biomedical Sciences, and Research Center for Bacterial Pathogenesis, Chang Gung University, Taoyuan, Taiwan.
PLoS One ; 10(12): e0144306, 2015.
Article en En | MEDLINE | ID: mdl-26669836
The superior antimicrobial properties of silver nanoparticles (Ag NPs) are well-documented, but the exact mechanisms underlying Ag-NP microbial toxicity remain the subject of intense debate. Here, we show that Ag-NP concentrations as low as 10 ppm exert significant toxicity against Bacillus subtilis, a beneficial bacterium ubiquitous in the soil. Growth arrest and chromosomal DNA degradation were observed, and flow cytometric quantification of propidium iodide (PI) staining also revealed that Ag-NP concentrations of 25 ppm and above increased membrane permeability. RedoxSensor content analysis and Phag-GFP expression analysis further indicated that reductase activity and cytosolic protein expression decreased in B. subtilis cells treated with 10-50 ppm of Ag NPs. We conducted X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses to directly clarify the valence and fine structure of Ag atoms in B. subtilis cells placed in contact with Ag NPs. The results confirmed the Ag species in Ag NP-treated B. subtilis cells as Ag2O, indicating that Ag-NP toxicity is likely mediated by released Ag+ ions from Ag NPs, which penetrate bacterial cells and are subsequently oxidized intracellularly to Ag2O. These findings provide conclusive evidence for the role of Ag+ ions in Ag-NP microbial toxicity, and suggest that the impact of inappropriately disposed Ag NPs to soil and water ecosystems may warrant further investigation.
Asunto(s)

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Plata / Bacillus subtilis / Nanopartículas del Metal / Antiinfecciosos Idioma: En Año: 2015 Tipo del documento: Article

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Plata / Bacillus subtilis / Nanopartículas del Metal / Antiinfecciosos Idioma: En Año: 2015 Tipo del documento: Article