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RNA-sequencing reveals multitude effects of silver nanoparticles on Pseudomonas aeruginosa biofilms


The recent years have witnessed the capabilities of silver nanoparticles (SNP) as a potent antimicrobial agent. This has resulted in discharge of SNP in the environments and the concentration of particles is steadily increasing. The microbicidal effects of SNP are a serious cause of concern because even low concentrations are likely to cause perturbations in microbial biofilms in the aquatic ecosystems causing cascading effects on higher life forms. A clear understanding about ‘particles-specific’ versus the ‘ion-specific’ effects on functional genes, particularly in biofilms is still lacking. We performed a genome-wide transcriptome analysis (via RNA-Seq) of pre-formed Pseudomonas aeruginosa biofilms in presence of SNP and Ag+ at a concentration of 3.12 µg/mL. Results of RNA-Seq analysis indicate differential expression of transcripts, 1599 in response to SNP and 2458 for Ag+ (i.e. 28 and 43%) as compared to the untreated biofilms. ‘Particles-specific’ effects were evident in the genes involved in biofilm adhesion, dispersion, including vital cellular processes; and genes involved in alkane degradation and denitrification were downregulated. Quantitative real time-PCR data on selected genes substantiated our observations. Scanning electron microscopy and confocal microscopy revealed alterations in cell morphology and a significant reduction in biofilm thickness, indicating dispersion. In medical settings, SNP can eradicate biofilms probably resolving the antibiotic crisis and reduce emerging drug resistance but overuse of particles in consumer products needs regulations so that nutrient cycling, bioremediation, and degradation of xenobiotics, etc. are not adversely affected. These results indeed warrant additional studies involving complex microbial communities.

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Publication details

The article was received on 14 Nov 2018, accepted on 08 Apr 2019 and first published on 08 Apr 2019

Article type: Paper
DOI: 10.1039/C8EN01286E
Citation: Environ. Sci.: Nano, 2019, Accepted Manuscript

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    RNA-sequencing reveals multitude effects of silver nanoparticles on Pseudomonas aeruginosa biofilms

    N. Singh, K. Paknikar and J. M. Rajwade, Environ. Sci.: Nano, 2019, Accepted Manuscript , DOI: 10.1039/C8EN01286E

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