Transcriptome profile with 20 nm silver nanoparticles in yeast.

Engineered nanomaterials are commercially used in everyday products including zinc sunscreens and water-resistant fabrics and surfaces. Therefore, understanding the effects of engineered nanomaterials on the environment is crucial for the responsible use of these technologies. We investigated the effects of 20 nm spherical citrate-coated silver nanoparticles (AgNPs) on the budding yeast Saccharomyces cerevisiae. Our growth assay showed that AgNPs have an inhibitory effect on yeast growth with concentrations above 5 μg/mL. Hundreds of genes in AgNP-treated cells were differentially expressed according to our transcriptome analysis based on RNAseq, including genes implicated in rRNA processing, ribosome biogenesis, cell wall formation, cell membrane integrity and mitochondrial functions. In particular, genes whose functions are associated with processing of small and large subunits of ribosomes were upregulated, while genes for cell wall/plasma membrane/mitochondrial integrity were downregulated. Consistently, our cell wall stability assay confirmed that cells with AgNPs are more susceptible to cell wall damage than non-treated cells. Levels of four significantly altered genes with AgNPs, including FAF1, SDA1, TIR1 and DAN1, were validated by reproducible results with RT-qPCR assays. Our transcriptome profile leads us to conclude that the exposure of cells to sublethal amounts of AgNPs affects many cellular processes negatively.