Commonalities and Differences in the Transcriptional Response of the Model Fungus Saccharomyces cerevisiae to Different Commercial Graphene Oxide Materials.

Felix Laguna-Teno,Maria Suarez-Diez,Juan Antonio Tamayo-Ramos

doi:10.3389/fmicb.2020.01943

Felix Laguna-Teno, Maria Suarez-Diez + Show 1 more

Open Access

https://doi.org/10.3389/fmicb.2020.01943

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Abstract

Graphene oxide has become a very appealing nanomaterial during the last years for many different applications, but its possible impact in different biological systems remains unclear. Here, an assessment to understand the toxicity of different commercial graphene oxide nanomaterials on the unicellular fungal model organism Saccharomyces cerevisiae was performed. For this task, an RNA purification protocol was optimized to avoid the high nucleic acid absorption capacity of graphene oxide. The developed protocol is based on a sorbitol gradient separation process for the isolation of adequate ribonucleic acid levels (in concentration and purity) from yeast cultures exposed to the carbon derived nanomaterial. To pinpoint potential toxicity mechanisms and pathways, the transcriptome of S. cerevisiae exposed to 160 mg L–1 of monolayer graphene oxide (GO) and graphene oxide nanocolloids (GOC) was studied and compared. Both graphene oxide products induced expression changes in a common group of genes (104), many of them related to iron homeostasis, starvation and stress response, amino acid metabolism and formate catabolism. Also, a high number of genes were only differentially expressed in either GO (236) or GOC (1077) exposures, indicating that different commercial products can induce specific changes in the physiological state of the fungus.

Highlights

Graphene oxide is a nanomaterial of great industrial interest, and many public and private initiatives have been launched during the last decade for the development of new technologies around this 2D carbon derived product (Shapira et al, 2016)
Graphene oxide risk assessment studies have been focused on mammalian cell lines and laboratory animals, where different mechanisms associated to its potential toxicity have been determined, namely, physical destruction, induction of oxidative stress, DNA damage, inflammatory response, apoptosis, autophagy, and necrosis (Sanchez et al, 2012; Ou et al, 2016; Ema et al, 2017)
Optimization of RNA Isolation From S. cerevisiae Cells Exposed to Different Commercial Graphene Oxide Products

Summary

INTRODUCTION

Graphene oxide is a nanomaterial of great industrial interest, and many public and private initiatives have been launched during the last decade for the development of new technologies around this 2D carbon derived product (Shapira et al, 2016). Few research works have been done using the fungal genetic model Saccharomyces cerevisiae, to understand the potential toxicity of graphene oxide and other carbon derived nanomaterials (Bayat et al, 2014; Yu et al, 2017; Zhu et al, 2017, 2018), highlighting the need for more thorough studies assessing the global cellular response. At sublethal concentrations, cell growth and metabolism were reduced, possibly due to the iron chelating properties of graphene oxide (Yu et al, 2017) In this regard, a relevant binding capacity for metal ions and positively charged organic molecules has been assigned to this nanomaterial, through electrostatic interaction and coordination (Ali et al, 2019). An optimized protocol for RNA isolation from fungal cells exposed to graphene oxide, was developed too

MATERIALS AND METHODS

RESULTS AND DISCUSSION

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