scholarly journals Effects of Oxygen Availability on Acetic Acid Tolerance and Intracellular pH in Dekkera bruxellensis

2016 ◽  
Vol 82 (15) ◽  
pp. 4673-4681 ◽  
Author(s):  
Claudia Capusoni ◽  
Stefania Arioli ◽  
Paolo Zambelli ◽  
M. Moktaduzzaman ◽  
Diego Mora ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Acetic Acid ◽  
Intracellular Ph ◽  
Acid Tolerance ◽  
Oxygen Availability ◽  
Industrial Processes ◽  
Dekkera Bruxellensis ◽  
Acetic Acid Tolerance ◽  
Content Type

ABSTRACTThe yeastDekkera bruxellensis, associated with wine and beer production, has recently received attention, because its high ethanol and acid tolerance enables it to compete withSaccharomyces cerevisiaein distilleries that produce fuel ethanol. We investigated how different cultivation conditions affect the acetic acid tolerance ofD. bruxellensis. We analyzed the ability of two strains (CBS 98 and CBS 4482) exhibiting different degrees of tolerance to grow in the presence of acetic acid under aerobic and oxygen-limited conditions. We found that the concomitant presence of acetic acid and oxygen had a negative effect onD. bruxellensisgrowth. In contrast, incubation under oxygen-limited conditions resulted in reproducible growth kinetics that exhibited a shorter adaptive phase and higher growth rates than those with cultivation under aerobic conditions. This positive effect was more pronounced in CBS 98, the more-sensitive strain. Cultivation of CBS 98 cells under oxygen-limited conditions improved their ability to restore their intracellular pH upon acetic acid exposure and to reduce the oxidative damage to intracellular macromolecules caused by the presence of acetic acid. This study reveals an important role of oxidative stress in acetic acid tolerance inD. bruxellensis, indicating that reduced oxygen availability can protect against the damage caused by the presence of acetic acid. This aspect is important for optimizing industrial processes performed in the presence of acetic acid.IMPORTANCEThis study reveals an important role of oxidative stress in acetic acid tolerance inD. bruxellensis, indicating that reduced oxygen availability can have a protective role against the damage caused by the presence of acetic acid. This aspect is important for the optimization of industrial processes performed in the presence of acetic acid.

scholarly journals A CRISPR Interference Screen of Essential Genes Reveals that Proteasome Regulation Dictates Acetic Acid Tolerance in Saccharomyces cerevisiae

mSystems ◽  
2021 ◽  
Author(s):  
Vaskar Mukherjee ◽  
Ulrika Lind ◽  
Robert P. St. Onge ◽  
Anders Blomberg ◽  
Yvonne Nygård
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Acid Tolerance ◽  
Essential Genes ◽  
Industrial Yeast ◽  
Acetic Acid Tolerance ◽  
Content Type ◽  
Fuels And Chemicals ◽  
Proteasome Regulation ◽  
And Oxidative Stress

Acetic acid is inhibitory to the growth of the yeast Saccharomyces cerevisiae , causing ATP starvation and oxidative stress, which leads to the suboptimal production of fuels and chemicals from lignocellulosic biomass. In this study, where each strain of a CRISPRi library was characterized individually, many essential and respiratory growth-essential genes that regulate tolerance to acetic acid were identified, providing a new understanding of the stress response of yeast and new targets for the bioengineering of industrial yeast.

scholarly journals The Cytosolic pH of Individual Saccharomyces cerevisiae Cells Is a Key Factor in Acetic Acid Tolerance

2015 ◽  
Vol 81 (22) ◽  
pp. 7813-7821 ◽  
Author(s):  
Miguel Fernández-Niño ◽  
Maribel Marquina ◽  
Steve Swinnen ◽  
Boris Rodríguez-Porrata ◽  
Elke Nevoigt ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Synthetic Medium ◽  
Acid Tolerance ◽  
Population Level ◽  
Acetic Acid Tolerance ◽  
Cytosolic Ph ◽  
Content Type ◽  
Key Factor ◽  
The Difference

ABSTRACTIt was shown recently that individual cells of an isogenicSaccharomyces cerevisiaepopulation show variability in acetic acid tolerance, and this variability affects the quantitative manifestation of the trait at the population level. In the current study, we investigated whether cell-to-cell variability in acetic acid tolerance could be explained by the observed differences in the cytosolic pHs of individual cells immediately before exposure to the acid. Results obtained with cells of the strain CEN.PK113-7D in synthetic medium containing 96 mM acetic acid (pH 4.5) showed a direct correlation between the initial cytosolic pH and the cytosolic pH drop after exposure to the acid. Moreover, only cells with a low initial cytosolic pH, which experienced a less severe drop in cytosolic pH, were able to proliferate. A similar correlation between initial cytosolic pH and cytosolic pH drop was also observed in the more acid-tolerant strain MUCL 11987-9. Interestingly, a fraction of cells in the MUCL 11987-9 population showed initial cytosolic pH values below the minimal cytosolic pH detected in cells of the strain CEN.PK113-7D; consequently, these cells experienced less severe drops in cytosolic pH. Although this might explain in part the difference between the two strains with regard to the number of cells that resumed proliferation, it was observed that all cells from strain MUCL 11987-9 were able to proliferate, independently of their initial cytosolic pH. Therefore, other factors must also be involved in the greater ability of MUCL 11987-9 cells to endure strong drops in cytosolic pH.

scholarly journals Enhancement of Acetic Acid Tolerance in Saccharomyces cerevisiae by Overexpression of theHAA1Gene, Encoding a Transcriptional Activator

2012 ◽  
Vol 78 (22) ◽  
pp. 8161-8163 ◽  
Author(s):  
Koichi Tanaka ◽  
Yukari Ishii ◽  
Jun Ogawa ◽  
Jun Shima
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Transcriptional Activator ◽  
Wild Type ◽  
Acetic Acid Tolerance ◽  
Content Type ◽  
In The Wild ◽  
Overexpressing Strain

ABSTRACTHaa1 is a transcriptional activator required forSaccharomyces cerevisiaeadaptation to weak acids. Here we show that the constitutiveHAA1-overexpressing strain acquired a higher level of acetic acid tolerance. Under conditions of acetic acid stress, the intracellular level of acetic acid was significantly lower inHAA1-overexpressing cells than in the wild-type cells.

scholarly journals Eukaryotic translation factor eIF5A contributes to acetic acid tolerance in Saccharomyces cerevisiae via transcriptional factor Ume6p

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yanfei Cheng ◽  
Hui Zhu ◽  
Zhengda Du ◽  
Xuena Guo ◽  
Chenyao Zhou ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Adaptive Response ◽  
Acid Tolerance ◽  
Peptide Bond ◽  
Transcriptional Factor ◽  
Yeast Cells ◽  
Acetic Acid Tolerance ◽  
Translation Factor ◽  
Industrial Strains

Abstract Background Saccharomyces cerevisiae is well-known as an ideal model system for basic research and important industrial microorganism for biotechnological applications. Acetic acid is an important growth inhibitor that has deleterious effects on both the growth and fermentation performance of yeast cells. Comprehensive understanding of the mechanisms underlying S. cerevisiae adaptive response to acetic acid is always a focus and indispensable for development of robust industrial strains. eIF5A is a specific translation factor that is especially required for the formation of peptide bond between certain residues including proline regarded as poor substrates for slow peptide bond formation. Decrease of eIF5A activity resulted in temperature-sensitive phenotype of yeast, while up-regulation of eIF5A protected transgenic Arabidopsis against high temperature, oxidative or osmotic stress. However, the exact roles and functional mechanisms of eIF5A in stress response are as yet largely unknown. Results In this research, we compared cell growth between the eIF5A overexpressing and the control S. cerevisiae strains under various stressed conditions. Improvement of acetic acid tolerance by enhanced eIF5A activity was observed all in spot assay, growth profiles and survival assay. eIF5A prompts the synthesis of Ume6p, a pleiotropic transcriptional factor containing polyproline motifs, mainly in a translational related way. As a consequence, BEM4, BUD21 and IME4, the direct targets of Ume6p, were up-regulated in eIF5A overexpressing strain, especially under acetic acid stress. Overexpression of UME6 results in similar profiles of cell growth and target genes transcription to eIF5A overexpression, confirming the role of Ume6p and its association between eIF5A and acetic acid tolerance. Conclusion Translation factor eIF5A protects yeast cells against acetic acid challenge by the eIF5A-Ume6p-Bud21p/Ime4p/Bem4p axles, which provides new insights into the molecular mechanisms underlying the adaptive response and tolerance to acetic acid in S. cerevisiae and novel targets for construction of robust industrial strains.

scholarly journals Sphingolipid biosynthesis upregulation by TOR complex 2–Ypk1 signaling during yeast adaptive response to acetic acid stress

2016 ◽  
Vol 473 (23) ◽  
pp. 4311-4325 ◽  
Author(s):  
Joana F. Guerreiro ◽  
Alexander Muir ◽  
Subramaniam Ramachandran ◽  
Jeremy Thorner ◽  
Isabel Sá-Correia
Keyword(s):  
Acetic Acid ◽  
Protein Kinase ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Acid Stress ◽  
Acid Tolerance ◽  
Industrial Biotechnology ◽  
Acetic Acid Tolerance ◽  
Spoilage Yeasts ◽  
Sphingolipid Biosynthesis

Acetic acid-induced inhibition of yeast growth and metabolism limits the productivity of industrial fermentation processes, especially when lignocellulosic hydrolysates are used as feedstock in industrial biotechnology. Tolerance to acetic acid of food spoilage yeasts is also a problem in the preservation of acidic foods and beverages. Thus understanding the molecular mechanisms underlying adaptation and tolerance to acetic acid stress is increasingly important in industrial biotechnology and the food industry. Prior genetic screens for Saccharomyces cerevisiae mutants with increased sensitivity to acetic acid identified loss-of-function mutations in the YPK1 gene, which encodes a protein kinase activated by the target of rapamycin (TOR) complex 2 (TORC2). We show in the present study by several independent criteria that TORC2–Ypk1 signaling is stimulated in response to acetic acid stress. Moreover, we demonstrate that TORC2-mediated Ypk1 phosphorylation and activation is necessary for acetic acid tolerance, and occurs independently of Hrk1, a protein kinase previously implicated in the cellular response to acetic acid. In addition, we show that TORC2–Ypk1-mediated activation of l-serine:palmitoyl-CoA acyltransferase, the enzyme complex that catalyzes the first committed step of sphingolipid biosynthesis, is required for acetic acid tolerance. Furthermore, analysis of the sphingolipid pathway using inhibitors and mutants indicates that it is production of certain complex sphingolipids that contributes to conferring acetic acid tolerance. Consistent with that conclusion, promoting sphingolipid synthesis by adding exogenous long-chain base precursor phytosphingosine to the growth medium enhanced acetic acid tolerance. Thus appropriate modulation of the TORC2–Ypk1–sphingolipid axis in industrial yeast strains may have utility in improving fermentations of acetic acid-containing feedstocks.

scholarly journals EfaR Is a Major Regulator of Enterococcus faecalis Manganese Transporters and Influences Processes Involved in Host Colonization and Infection

2013 ◽  
Vol 81 (3) ◽  
pp. 935-944 ◽  
Author(s):  
M. C. Abrantes ◽  
J. Kok ◽  
M. de F. Lopes
Keyword(s):  
Oxidative Stress ◽  
Metal Ions ◽  
Enterococcus Faecalis ◽  
Bacterial Endocarditis ◽  
Nosocomial Pathogen ◽  
Host Colonization ◽  
Content Type ◽  
Bacterial Pathogenicity

ABSTRACTMetal ions, in particular manganese, are important modulators of bacterial pathogenicity. However, little is known about the role of manganese-dependent proteins in the nosocomial pathogenEnterococcus faecalis, a major cause of bacterial endocarditis. The present study demonstrates that the DtxR/MntR family metalloregulator EfaR ofE. faecaliscontrols the expression of several of its regulon members in a manganese-dependent way. We also show thatefaRinactivation impairs the ability ofE. faecalisto form biofilms, to survive inside macrophages, and to tolerate oxidative stress. Our results reveal that EfaR is an important modulator ofE. faecalisvirulence and link manganese homeostasis to enterococcal pathogenicity.

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