Dataset Information

Systems-level Analysis of Oxygen Exposure in Zymomonas mobilis: Implications for Isoprenoid Production

ABSTRACT: Zymomonas mobilis is an aerotolerant anaerobe and prolific ethanologen with attractive characteristics for industrial biofuel production. Here, we examine the effect of oxygen exposure on metabolism and gene expression in Z. mobilis by combining targeted metabolomics, mRNA sequencing, and shotgun proteomics. We found that exposure to oxygen profoundly influenced metabolism, inducing both transient metabolic bottlenecks and long-term metabolic remodeling. In particular, oxygen induced a severe but temporary metabolic bottleneck in the methyl erythritol 4-phosphate pathway for isoprenoid biosynthesis, likely caused by oxidative damage to the iron-sulfur co-factors of the final two enzymes of the pathway. This bottleneck was resolved with minimal changes in expression level of enzymes in the pathway but pronounced upregulation of enzymes related to iron-sulfur cluster maintenance and biogenesis (i.e. flavodoxin reductase and the suf operon). We also detected prominent changes in glucose utilization under aerobic conditions. Specifically, we observed increased gluconate production following exposure to oxygen, accounting for 18% of glucose uptake after 24 hours of aerobic growth. Our results suggest that under aerobic conditions, electrons from the oxidation of glucose to gluconate are delivered to the electron transport chain to minimize oxidative damage by reducing reactive oxygen species such as H2O2. This model is supported by the simultaneous upregulation of three membrane-bound dehydrogenases, cytochrome c peroxidase, and a cytochrome bd terminal oxidase.

OTHER RELATED OMICS DATASETS IN: GSE125123

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Zymomonas Mobilis

TISSUE(S): Permanent Cell Line Cell, Cell Culture

DISEASE(S): Disease Free

SUBMITTER: Alexander Hebert

LAB HEAD: Joshua Jacques Coon

PROVIDER: PXD011545 | Pride | 2019-01-18

REPOSITORIES: Pride

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Publications

Systems-Level Analysis of Oxygen Exposure in <i>Zymomonas mobilis</i>: Implications for Isoprenoid Production.

Martien Julia I JI Hebert Alexander S AS Stevenson David M DM Regner Matthew R MR Khana Daven B DB Coon Joshua J JJ Amador-Noguez Daniel D

mSystems 20190101 1

Zymomonas mobilis is an aerotolerant anaerobe and prolific ethanologen with attractive characteristics for industrial bioproduct generation. However, there is currently insufficient knowledge of the impact that environmental factors have on flux through industrially relevant biosynthetic pathways. Here, we examined the effect of oxygen exposure on metabolism and gene expression in Z. mobilis by combining targeted metabolomics, mRNA sequencing, and shotgun proteomics. We found that exposure to ox ...[more]

PMID: 30801024

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Project description:Saccharomyces cerevisiae is currently widely used as a model to study chronological aging of metazoan cells. Chronological aging is typically studied in aerobic stationary phase (SP) cultures, i.e. the final stage of batch cultures in which growth is arrested due to exogenous carbon source exhaustion. Survival of yeast cells in SP defines their chronological lifespan (CLS). S. cerevisiae SP cultures have strongly contributed to the understanding of cellular mechanisms involved in aging and indicated a key role for oxygen. Oxygen is the natural starting point for reactive oxygen species (ROS) that may both have malignant and beneficial effects on aging. In addition, oxygen allows yeast to grow on ethanol and organic acids formed during the initial respiro-fermentative growth phase on glucose. This post-diauxic phase is hallmarked by reduced growth rates, increased expression of genes involved in SP survival, and increased stress resistance. To date, the role of oxygen and respiration in aging has mostly been studied using respiratory deficient mutants, and respiration repressing agents. However, genetic or chemical interventions may result in unwanted side effects that influence survival in SP. We therefore followed a different approach to evaluate the impact of oxygen availability on yeast robustness in SP, i.e. its CLS and stress resistance, by using the capability of S. cerevisiae to grow under anaerobic conditions. A thorough physiological comparison of strictly anaerobic and aerobic SP cultures revealed that the presence of oxygen during growth and aging of S. cerevisiae strongly affects its energetic status, longevity and stress tolerance in a positive way. Combining the physiological data with genome-wide expression analysis revealed that the oxygen-dependent diauxic growth phase enabled the full induction of robustness in S. cerevisiae, and points to appropriate pre-conditioning of cells as a crucial factor to survive starvation. These findings highlight the importance of exogenous energy availability in the conditions leading to growth arrest, and bring new insight on the role of oxygen in the aging of eukaryotes. The goal of the present study is to evaluate the impact of oxygen availability on yeast longevity. More specifically, the questions addressed are whether the presence of a â??conditioningâ?? post-diauxic phase and the ability to utilize efficiently reserves, characteristics of aerobicity, affects yeast survival during stationary phase. To this end, S. cerevisiae was cultivated in well controlled bioreactors under the presence or absence of oxygen. S. cerevisiaeâ??s response to oxygen availability was monitored by an in-depth physiological analysis combined with genome wide expression analysis.

Dataset Information

Systems-level Analysis of Oxygen Exposure in Zymomonas mobilis: Implications for Isoprenoid Production

Publications

Systems-Level Analysis of Oxygen Exposure in <i>Zymomonas mobilis</i>: Implications for Isoprenoid Production.

Similar Datasets

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