Oxidative Stress Responses and Nutrient Starvation in MCHM Treated Saccharomyces cerevisiae

Abstract

In 2014, the coal cleaning chemical 4-methylcyclohexane methanol (MCHM) spilled into the water supply for 300,000 West Virginians. Initial toxicology tests showed relatively mild results, but the underlying effects on cellular biology were underexplored. Treated wildtype yeast cells grew poorly, but there was only a small decrease in cell viability. Cell cycle analysis revealed an absence of cells in S phase within thirty minutes of treatment. Cells accumulated in G1 over a six-hour time course, indicating arrest instead of death. A genetic screen of the haploid knockout collection revealed 329 high confidence genes required for optimal growth in MCHM. These genes encode three major cell processes: mitochondrial gene expression/translation, the vacuolar ATPase, and aromatic amino acid biosynthesis. The transcriptome showed an upregulation of pleiotropic drug response genes and amino acid biosynthetic genes and downregulation in ribosome biosynthesis. Analysis of these datasets pointed to environmental stress response activation upon treatment. Overlap in datasets included the aromatic amino acid genes ARO1, ARO3, and four of the five TRP genes. This implicated nutrient deprivation as the signal for stress response. Excess supplementation of nutrients and amino acids did not improve growth on MCHM, so the source of nutrient deprivation signal is still unclear. Reactive oxygen species and DNA damage were directly detected with MCHM treatment, but timepoints showed these accumulated slower than cells arrested. We propose that wildtype cells arrest from nutrient deprivation and survive, accumulating oxidative damage through the implementation of robust environmental stress responses.

Yeast of Eden: microbial resistance to glyphosate from a yeast perspective

“…Natural genetic variation in Aro1 between a sake strain and a European wine strain links nitrogen consumption with growth (Cubillos et al 2017 ). ARO1 mutants are sensitive to many chemicals (Ayers et al 2020 ). While further down the tryptophan branch, trp1 mutants are sensitive to DNA damage (Brown et al 2006 ), detergents (Schroeder and Ikui 2019 ), isobutanol (Liu et al 2021 ), ethanol (Stanley et al 2010 ), cold (Brachmann et al 1998 ; Leng and Song 2016 ), pH (González et al 2008 ), rapamycin (González et al 2008 ), and MCHM (Ayers et al 2020 ).…”

“…ARO1 mutants are sensitive to many chemicals (Ayers et al 2020 ). While further down the tryptophan branch, trp1 mutants are sensitive to DNA damage (Brown et al 2006 ), detergents (Schroeder and Ikui 2019 ), isobutanol (Liu et al 2021 ), ethanol (Stanley et al 2010 ), cold (Brachmann et al 1998 ; Leng and Song 2016 ), pH (González et al 2008 ), rapamycin (González et al 2008 ), and MCHM (Ayers et al 2020 ). These chemicals appear to generate oxidative stress, to which trp mutants are particularly sensitive.…”

Overexpression of SIRT3 Suppresses Oxidative Stress-induced Neurotoxicity and Mitochondrial Dysfunction in Dopaminergic Neuronal Cells

“…Several studies have shown that starvation can induce the oxidative stress [57]. Starvation-induced oxidative stress is closely related to starvation-induced cell toxicity [58][59][60][61]. Furthermore, Sirt3 de- [62][63][64][65].…”

“…Several studies have shown that starvation can induce the oxidative stress [ 57 ]. Starvation-induced oxidative stress is closely related to starvation-induced cell toxicity [ 58 - 61 ]. Furthermore, Sirt3 deficiency leads to mitochondrial dysfunction and increase the vulnerability of cells to oxidative stress [ 62 - 65 ].…”

A comprehensive review and comparison of L-tryptophan biosynthesis in Saccharomyces cerevisiae and Escherichia coli

“…To cope with ROS, yeast cells quickly adjust and synthesize self-healing substanceslike tryptophan. Other than malnutrition, L-Trp has been suggested to be connected to stress tolerance ( Ayers et al, 2020 ). The expressions of genes involved in amino acid synthesis and transportation, such as Prs1 , Prs3 , Tat1 , and Tat2 , must be interrupted to weaken the metabolism of tryptophan and other amino acids.…”