| 1. |
- Bendixsen, Devin P., et al.
(författare)
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Saccharomyces yeast hybrids on the rise
- 2022
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Ingår i: Yeast. - : Wiley. - 0749-503X .- 1097-0061. ; 39:1-2, s. 40-54
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Forskningsöversikt (refereegranskat)abstract
- Saccharomyces hybrid yeasts are receiving increasing attention as a powerful model system to understand adaptation to environmental stress and speciation mechanisms, using experimental evolution and omics techniques. We compiled all genomic resources available from public repositories of the eight recognized Saccharomyces species and their interspecific hybrids. We present the newest numbers on genomes sequenced, assemblies, annotations, and sequencing runs, and an updated species phylogeny using orthogroup inference. While genomic resources are highly skewed towards Saccharomyces cerevisiae, there is a noticeable movement to use wild, recently discovered yeast species in recent years. To illustrate the degree and potential causes of reproductive isolation, we reanalyzed published data on hybrid spore viabilities across the entire genus and tested for the role of genetic, geographic, and ecological divergence within and between species (28 cross types and 371 independent crosses). Hybrid viability generally decreased with parental genetic distance likely due to antirecombination and negative epistasis, but notable exceptions emphasize the importance of strain-specific structural variation and ploidy differences. Surprisingly, the viability of crosses within species varied widely, from near reproductive isolation to near-perfect viability. Geographic and ecological origins of the parents predicted cross viability to an extent, but with certain caveats. Finally, we highlight publication trends in the field and point out areas of special interest, where hybrid yeasts are particularly promising for innovation through research and development, and experimental evolution and fermentation.
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| 2. |
- Boynton, Primrose, et al.
(författare)
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Yeast ecology and communities
- 2022
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Ingår i: Yeast. - : Wiley. - 0749-503X .- 1097-0061. ; 39:1-2, s. 3-3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Guaragnella, Nicoletta, et al.
(författare)
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Acetic acid stress in budding yeast: From molecular mechanisms to applications
- 2021
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Ingår i: Yeast. - : Wiley. - 1097-0061 .- 0749-503X. ; 38:7, s. 391-400
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Tidskriftsartikel (refereegranskat)abstract
- Acetic acid stress represents a frequent challenge to counteract for yeast cells under several environmental conditions and industrial bioprocesses. The molecular mechanisms underlying its response have been mostly elucidated in the budding yeast Saccharomyces cerevisiae, where acetic acid can be either a physiological substrate or a stressor. This review will focus on acetic acid stress and its response in the context of cellular transport, pH homeostasis, metabolism and stress-signalling pathways. This information has been integrated with the results obtained by multi-omics, synthetic biology and metabolic engineering approaches aimed to identify major cellular players involved in acetic acid tolerance. In the production of biofuels and renewable chemicals from lignocellulosic biomass, the improvement of acetic acid tolerance is a key factor. In this view, how this knowledge could be used to contribute to the development and competitiveness of yeast cell factories for sustainable applications will be also discussed.
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| 4. |
- Meza, Eugenio, 1975, et al.
(författare)
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Development of a method for heat shock stress assessment in yeast based on transcription of specific genes
- 2021
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Ingår i: Yeast. - : Wiley. - 1097-0061 .- 0749-503X. ; 38:10, s. 549-565
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Tidskriftsartikel (refereegranskat)abstract
- All living cells, including yeast cells, are challenged by different types of stresses in their environments and must cope with challenges such as heat, chemical stress, or oxidative damage. By reversibly adjusting the physiology while maintaining structural and genetic integrity, cells can achieve a competitive advantage and adapt environmental fluctuations. The yeast Saccharomyces cerevisiae has been extensively used as a model for study of stress responses due to the strong conservation of many essential cellular processes between yeast and human cells. We focused here on developing a tool to detect and quantify early responses using specific transcriptional responses. We analyzed the published transcriptional data on S. cerevisiae DBY strain responses to 10 different stresses in different time points. The principal component analysis (PCA) and the Pearson analysis were used to assess the stress response genes that are highly expressed in each individual stress condition. Except for these stress response genes, we also identified the reference genes in each stress condition, which would not be induced under stress condition and show stable transcriptional expression over time. We then tested our candidates experimentally in the CEN.PK strain. After data analysis, we identified two stress response genes (UBI4 and RRP) and two reference genes (MEX67 and SSY1) under heat shock (HS) condition. These genes were further verified by real-time PCR at mild (42°C), severe (46°C), to lethal temperature (50°C), respectively.
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| 5. |
- Passoth, Volkmar, et al.
(författare)
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Oleaginous yeasts for biochemicals, biofuels and food from lignocellulose-hydrolysate and crude glycerol
- 2023
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Ingår i: Yeast. - : Wiley. - 0749-503X .- 1097-0061. ; 40
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Forskningsöversikt (refereegranskat)abstract
- Microbial lipids produced from lignocellulose and crude glycerol (CG) can serve as sustainable alternatives to vegetable oils, whose production is, in many cases, accompanied by monocultures, land use changes or rain forest clearings. Our projects aim to understand the physiology of microbial lipid production by oleaginous yeasts, optimise the production and establish novel applications of microbial lipid compounds. We have established methods for fermentation and intracellular lipid quantification. Following the kinetics of lipid accumulation in different strains, we found high variability in lipid formation even between very closely related oleaginous yeast strains on both, wheat straw hydrolysate and CG. For example, on complete wheat straw hydrolysate, we saw that one Rhodotorula glutinis strain, when starting assimilating D-xylosealso assimilated the accumulated lipids, while a Rhodotorula babjevae strain could accumulate lipids on D-xylose. Two strains (Rhodotorula toruloides CBS 14 and R. glutinis CBS 3044) were found to be the best out of 27 tested to accumulate lipids on CG. Interestingly, the presence of hemicellulose hydrolysate stimulated glycerol assimilation in both strains. Apart from microbial oil, R. toruloides also produces carotenoids. The first attempts of extraction using the classical acetone-based method showed that beta-carotene is the major carotenoid. However, there are indications that there are also substantial amounts of torulene and torularhodin, which have a very high potential as antioxidants.
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| 6. |
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