Transcriptional response of Sacchromyces cerevisiae to change in oxygen provision

In industrial fermentations of Saccharomyces cerevisiae, transient changes in oxygen concentration commonly occur and it is important to understand the behaviour of cells during these changes. Saccharomyces cerevisiae CEN.PK113-1A was grown in glucose-limited chemostat culture with 1.0% and 20.9% O2 in the inlet gas (D= 0.10 /h, pH5, 30C). After steady state was achieved, oxygen was replaced with nitrogen and cultures were followed until new steady state was achieved. The overall responses to anaerobic conditions of cells initially in different conditions were very similar. Independent of initial culture conditions, transient downregulation of genes related to growth and cell proliferation, mitochondrial translation and protein import, and sulphate assimilation was seen. In addition, transient or permanent upregulation of genes related to protein degradation, and phosphate and amino acid uptake was observed in all cultures. However, only in the initially oxygen-limited cultures was a transient upregulation of genes related to fatty acid oxidation, peroxisomal biogenesis, oxidative phosphorylation, TCA cycle, response to oxidative stress, and pentose phosphate pathway observed. Furthermore, from the initially oxygen-limited conditions, a rapid response around the metabolites of upper glycolysis and the pentose phosphate pathway was seen, while from the initially fully aerobic conditions, a slower response around the pathways for utilisation of respiratory carbon sources was observed.

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Rintala E, Jouhten P, Toivari M, Wiebe MG, Maaheimo H, Penttilä M, Ruohonen L