scholarly journals Norwegian Kveik brewing yeasts are adapted to higher temperatures and produce fewer off-flavours under heat stress than commercial Saccharomyces cerevisiae American Ale yeast

2021 ◽  
Author(s):  
Dimitri Kits ◽  
Lars Marius Garshol
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Elevated Temperatures ◽  
Active Metabolites ◽  
Fermentation Temperature ◽  
Fusel Alcohols ◽  
Western Norway ◽  
Apparent Attenuation ◽  
Brewer’S Yeasts ◽  
Fine Tune ◽  
Brewing Yeasts

Norwegian kveik are a recently described family of domesticated Saccharomyces cerevisiae brewing yeasts used by farmhouse brewers in western Norway for generations to produce traditional Norwegian farmhouse ale. Kveik ale yeasts have been domesticated by farmhouse brewers through serial repitching of the yeast in warm wort (>30°C) punctuated by long periods of dry storage. Kveik yeasts are alcohol tolerant, flocculant, capable of utilizing maltose/maltotriose, phenolic off flavour negative, and exhibit elevated thermotolerance when compared to other modern brewer's yeasts belonging to the 'Beer 1' clade. However, the optimal fermentation and growth temperatures (Topt) for kveik ale yeasts and the influence of fermentation temperature of the production of flavour-active metabolites like fusel alcohols and sulfur compounds (H2S, SO2) are not known. Here we show that kveik ale yeasts have an elevated optimal fermentation temperature (Topt) when compared to commercial American Ale yeast (SafAle™ US-05) and that they produce fewer off-flavours at high temperatures (>30°C) when compared to commercial American Ale yeasts. The tested kveik yeasts show significantly higher maximum fermentation rates than American Ale yeast not only at elevated temperatures (>30°C), but also at 'typical' ale fermentation temperatures (20°C-25°C). Finally, we demonstrate that kveik ale yeasts are heterogeneous in their Topt and that they attenuate standard wort robustly above their Topt unlike our control American Ale yeast which showed very poor apparent attenuation in our standard wort at temperatures >> Topt. Our results provide further support that kveik yeasts may possess favourable fermentation kinetics and sensory properties compared to American Ale yeasts. The observations here provide a roadmap for brewers to fine tune their commercial fermentations using kveik ale yeasts for optimal performance and/or flavour impact.

scholarly journals Cdc55p, the B-type regulatory subunit of protein phosphatase 2A, has multiple functions in mitosis and is required for the kinetochore/spindle checkpoint in Saccharomyces cerevisiae.

1997 ◽  
Vol 17 (2) ◽  
pp. 620-626 ◽  
Author(s):  
Y Wang ◽  
D J Burke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Phosphatase ◽  
Elevated Temperatures ◽  
Protein Phosphatase 2A ◽  
Spindle Checkpoint ◽  
Mitotic Checkpoint ◽  
Regulatory Subunit ◽  
Phosphatase 2A ◽  
A Subunit ◽  
Normal Sensitivity

Saccharomyces cerevisiae, like most eucaryotic cells, can prevent the onset of anaphase until chromosomes are properly aligned on the mitotic spindle. We determined that Cdc55p (regulatory B subunit of protein phosphatase 2A [PP2A]) is required for the kinetochore/spindle checkpoint regulatory pathway in yeast. ctf13 cdc55 double mutants could not maintain a ctf13-induced mitotic delay, as determined by antitubulin staining and levels of histone H1 kinase activity. In addition, cdc55::LEU2 mutants and tpd3::LEU2 mutants (regulatory A subunit of PP2A) were nocodazole sensitive and exhibited the phenotypes of previously identified kinetochore/spindle checkpoint mutants. Inactivating CDC55 did not simply bypass the arrest that results from inhibiting ubiquitin-dependent proteolysis because cdc16-1 cdc55::LEU2 and cdc23-1 cdc55::LEU2 double mutants arrested normally at elevated temperatures. CDC55 is specific for the kinetochore/spindle checkpoint because cdc55 mutants showed normal sensitivity to gamma radiation and hydroxyurea. The conditional lethality and the abnormal cellular morphogenesis of cdc55::LEU2 were suppressed by cdc28F19, suggesting that the cdc55 phenotypes are dependent on the phosphorylation state of Cdc28p. In contrast, the nocodazole sensitivity of cdc55::LEU2 was not suppressed by cdc28F19. Therefore, the mitotic checkpoint activity of CDC55 (and TPD3) is independent of regulated phosphorylation of Cdc28p. Finally, cdc55::LEU2 suppresses the temperature sensitivity of cdc20-1, suggesting additional roles for CDC55 in mitosis.

Cloning and characterization of LOS1, a Saccharomyces cerevisiae gene that affects tRNA splicing

1987 ◽  
Vol 7 (3) ◽  
pp. 1208-1216 ◽  
Author(s):  
D J Hurt ◽  
S S Wang ◽  
Y H Lin ◽  
A K Hopper
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Elevated Temperatures ◽  
Trna Gene ◽  
Single Copy ◽  
Molecular Study ◽  
Trna Splicing ◽  
Intervening Sequences ◽  
Copy Gene

Saccharomyces cerevisiae strains carrying los1-1 mutations are defective in tRNA processing; at 37 degrees C, such strains accumulate tRNA precursors which have mature 5' and 3' ends but contain intervening sequences. Strains bearing los1-1 and an intron-containing ochre-suppressing tRNA gene, SUP4(0), also fail to suppress the ochre mutations ade2-1(0) and can1-100(0) at 34 degrees C. To understand the role of the LOS1 product in tRNA splicing, we initiated a molecular study of the LOS1 gene. Two plasmids, YEpLOS1 and YCpLOS1, that complement the los1-1 phenotype were isolated from the YEp24 and YCp50 libraries, respectively. YEpLOS1 and YCpLOS1 had overlapping restriction maps, indicating that the DNA in the overlapping segment could complement los1-1 when present in multiple or single copy. Integration of plasmid DNA at the LOS1 locus confirmed that these clones contained authentic LOS1 sequences. Southern analyses showed that LOS1 is a single copy gene. The locations of the LOS1 gene within YEpLOS1 and YCpLOS1 were determined by deletion and gamma-delta mapping. Two genomic disruptions of the LOS1 gene were constructed, i.e., an insertion of a 1.2-kilobase fragment carrying the yeast URA3 gene, los1::URA3, and a 2.4-kilobase deletion from the LOS1 gene, los1-delta V. Disruption or deletion of most of the LOS1 gene was not lethal; cells carrying the disrupted los1 alleles were viable and had phenotypes similar to those of cells carrying the los1-1 allele. Thus, it appears that the los1 gene product expedites tRNA splicing at elevated temperatures but is not essential for this process.

scholarly journals Punctuated Aneuploidization of the Budding Yeast Genome

Genetics ◽  
2020 ◽  
Vol 216 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Lydia R. Heasley ◽  
Ruth A. Watson ◽  
Juan Lucas Argueso
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Tumor Cells ◽  
Genomic Instability ◽  
High Frequency ◽  
Budding Yeast ◽  
Cell Types ◽  
Eukaryotic Cell ◽  
Yeast Genome ◽  
Single Chromosome ◽  
Brewing Yeasts

Remarkably complex patterns of aneuploidy have been observed in the genomes of many eukaryotic cell types, ranging from brewing yeasts to tumor cells. Such aberrant karyotypes are generally thought to take shape progressively over many generations, but evidence also suggests that genomes may undergo faster modes of evolution. Here, we used diploid Saccharomyces cerevisiae cells to investigate the dynamics with which aneuploidies arise. We found that cells selected for the loss of a single chromosome often acquired additional unselected aneuploidies concomitantly. The degrees to which these genomes were altered fell along a spectrum, ranging from simple events affecting just a single chromosome, to systemic events involving many. The striking complexity of karyotypes arising from systemic events, combined with the high frequency at which we detected them, demonstrates that cells can rapidly achieve highly altered genomic configurations during temporally restricted episodes of genomic instability.

scholarly journals Mistranslating tRNA identifies a deleterious S213P mutation in the Saccharomyces cerevisiae eco1-1 allele

2020 ◽  
Vol 98 (5) ◽  
pp. 624-630 ◽  
Author(s):  
Yanrui Zhu ◽  
Matthew D. Berg ◽  
Phoebe Yang ◽  
Raphaël Loll-Krippleber ◽  
Grant W. Brown ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Genetic Disease ◽  
Elevated Temperatures ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Standard Genetic Code ◽  
Gene Encoding ◽  
Chromatid Cohesion ◽  
Sensitive Allele

Mistranslation occurs when an amino acid not specified by the standard genetic code is incorporated during translation. Since the ribosome does not read the amino acid, tRNA variants aminoacylated with a non-cognate amino acid or containing a non-cognate anticodon dramatically increase the frequency of mistranslation. In a systematic genetic analysis, we identified a suppression interaction between tRNASerUGG, G26A, which mistranslates proline codons by inserting serine, and eco1-1, a temperature sensitive allele of the gene encoding an acetyltransferase required for sister chromatid cohesion. The suppression was partial, with a tRNA that inserts alanine at proline codons and not apparent for a tRNA that inserts serine at arginine codons. Sequencing of the eco1-1 allele revealed a mutation that would convert the highly conserved serine 213 within β7 of the GCN5-related N-acetyltransferase core to proline. Mutation of P213 in eco1-1 back to the wild-type serine restored the function of the enzyme at elevated temperatures. Our results indicate the utility of mistranslating tRNA variants to identify functionally relevant mutations and identify eco1 as a reporter for mistranslation. We propose that mistranslation could be used as a tool to treat genetic disease.

Comparison of the mitochondrial endonucleases from Neurospora crassa and Saccharomyces cerevisiae

1985 ◽  
Vol 31 (7) ◽  
pp. 654-656 ◽  
Author(s):  
Richard G. von Tigerstrom ◽  
Sheilah Stelmaschuk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Neurospora Crassa ◽  
Mode Of Action ◽  
Elevated Temperatures ◽  
Physiological Role ◽  
Intracellular Location ◽  
Substrate Specificities ◽  
Structural Differences ◽  
Specific Activities

The endonucleases from Neurospora crassa and Saccharomyces cerevisiae are not closely related antigenically. They also differ with respect to their activity at pH 8, their degree of hydrophobicity, and their sensitivity to elevated temperatures. However, the two nucleases have similar specific activities, are inhibited by EDTA, and have nearly identical substrate specificities. Since the enzymes also have the same mode of action and intracellular location, these similarities may indicate that they have the same physiological role despite their structural differences.

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