Zinc oxide and silver nanoparticles toxicity in the baker’s yeast, Saccharomyces cerevisiae
Citation
Márquez, I.G., Ghiyasvand, M., Massarsky, A., Babu, M., Samanfar, B., Omidi, K., Moon, T.W., Smith, M.L., Golshani, A. (2018). Zinc oxide and silver nanoparticles toxicity in the baker’s yeast, Saccharomyces cerevisiae. PLoS ONE, [online] 13(3), http://dx.doi.org/10.1371/journal.pone.0193111
Plain language summary
Engineered nanomaterials (ENMs) are increasingly integrated into everyday life. ENMs possess unique physical, chemical, and structural properties attributable to their small size (100 nm in at least one dimension). Zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs) are among the most commonly used ENMs. ZnONPs are present in numerous consumer products, especially in ultraviolet (UV) blocking cosmetics. ZnONPs effectively absorb UV-A and UV-B light through a process called band-gap absorption, and are less photoactive than titanium dioxide nanoparticles (TiO2NPs), which are also used in sunscreens. The current study uses a Gene Deletion Array (GDA) as a platform for a high-throughput functional genomic screening to enhance our understanding of ENM toxicity. The GDA is comprised of 4600 non-essential gene deletion strains of S. cerevisiae. We predict that strains with deletion of genes in a parallel, redundant pathway to that targeted by ZnONPs and/or AgNPs, will have increased sensitivity to these NPs, as was demonstrated for other compound. Highly sensitive strains are then categorized according to the cellular activity and function of the deleted genes, in order to deduce cellular pathways that are affected by these NPs.
Abstract
Engineered nanomaterials (ENMs) are increasingly incorporated into a variety of commercial applications and consumer products; however, ENMs may possess cytotoxic properties due to their small size. This study assessed the effects of two commonly used ENMs, zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs), in the model eukaryote Saccharomyces cerevisiae. A collection of 4600 S. cerevisiae deletion mutant strains was used to deduce the genes, whose absence makes S. cerevisiae more prone to the cytotoxic effects of ZnONPs or AgNPs. We demonstrate that S. cerevisiae strains that lack genes involved in transmembrane and membrane transport, cellular ion homeostasis, and cell wall organization or biogenesis exhibited the highest sensitivity to ZnONPs. In contrast, strains that lack genes involved in transcription and RNA processing, cellular respiration, and endocytosis and vesicular transport exhibited the highest sensitivity to AgNPs. Secondary assays confirmed that ZnONPs affected cell wall function and integrity, whereas AgNPs exposure decreased transcription, reduced endocytosis, and led to a dysfunctional electron transport system. This study supports the use of S. cerevisiae Gene Deletion Array as an effective high-throughput technique to determine cellular targets of ENM toxicity.