Search results for "YEAST"
showing 10 items of 792 documents
Adaptive response to wine selective pressures shapes the genome of a Saccharomyces interspecies hybrid
2021
During industrial processes, yeasts are exposed to harsh conditions, which eventually lead to adaptation of the strains. In the laboratory, it is possible to use experimental evolution to link the evolutionary biology response to these adaptation pressures for the industrial improvement of a specific yeast strain. In this work, we aimed to study the adaptation of a wine industrial yeast in stress conditions of the high ethanol concentrations present in stopped fermentations and secondary fermentations in the processes of champagne production. We used a commercial Saccharomyces cerevisiae × S. uvarum hybrid and assessed its adaptation in a modified synthetic must (M-SM) containing high ethan…
Genomics and the gene transcription kinetics in yeast.
2007
As an adaptive response to new conditions, mRNA concentrations in eukaryotes are readjusted after any environmental change. Although mRNA concentrations can be modified by altering synthesis and/or degradation rates, the rapidity of the transition to a new concentration depends on the regulation of mRNA stability. There are several plausible transcriptional strategies following environmental change, reflecting different degrees of compromise between speed of response and cost of synthesis. The recent development of genomic techniques now enables researchers to determine simultaneously (either directly or indirectly) the transcription rates and mRNA half-lifes, together with mRNA concentrati…
Dissemination of wine-related yeasts by migratory birds
2011
Summary The present work was undertaken to evaluate the contribution of migratory birds in the environmental dissemination of yeasts. Four sites (Mazara del Vallo, Lampedusa, Ustica and Linosa), representing the main stop-over points in Sicily, were analysed during spring and autumnal bird migration and 349 birds (belonging to 10 families) were ringed and analysed for yeast presence. A total of 125 yeasts were isolated and identified by a multiple genotypic approach, consisting of restriction fragment length polymorphism (RFLP) of 5.8S rRNA gene and 26S rRNA and sequencing of D1/D2 domain of the 26S rRNA gene, which resulted in the recognition of 18 species, including the technological rele…
Interactions between the yeast mitochondrial and nuclear genomes: isogenic suppressive and hypersuppressive petites differ in their resistance to the…
1990
In a previous paper we have shown that the alkaloid lycorine inhibits growth of rho+, mit- and rho-, strains of Saccharomyces cerevisiae, whereas strains devoid of mitochondrial DNA (rho degrees) are resistant to more than 200 micrograms/ml of the alkaloid. In this report we show that hypersuppressive petites are almost as resistant as rho degrees mutants, whereas isogenic rho- petites, which have retained longer segments of the genome, are sensitive to the drug.
Construction of a Trp commercial baker?s yeast strain by using food-safe-grade dominant drug resistance cassettes
2003
We have designed a food-safe-grade module for gene disruptions in commercial baker's yeast strains, which contains the G418 resistance cassette, KanMX4, flanked by direct repeats from the MEL1 gene of Saccharomyces cerevisiae. This module was used to obtain a Trp(-) auxotrophic mutant of the polyploid HY strain by successive targeting to the TRP1 locus and later in vivo excision of the kan(r) marker. Southern blot analysis indicated that HY contains five copies of the TRP1 gene. However, after four disruption rounds, a strain named HYtrpM(4), unable to grow in the absence of tryptophan, was selected. Southern and Northern analysis of HYtrpM(4) cells showed that a remaining functional wild-t…
A rapid method for the screening of plasmids in transformed yeast strains
1988
A method for the rapid screening of plasmids in yeast cells has been developed. The method is an adaptation of the currently used alkaline lysis methods forEscherichia coli plasmids. Following the conditions described, several dozen ofSaccharomyces cerevisiae-transformed clones can be analyzed for their plasmid content in less than 2 h. The plasmids obtained by this procedure are suitable for restriction analysis or forE. coli andS. cerevisiae transformation.
YJL159w does encode Pir2/Hsp150
2001
In this paper we compare the sequence of the gene HSP150/PIR2, independently determined by two different groups, with that present in the yeast database as YJL159w, determined within the Yeast Sequencing Project. Although YJL159w is believed to encode Hsp150/Pir2, there are important differences between the amino acid sequence coded by this ORF and that of HSP150/PIR2. To find out if this divergence is due to strain polymorphism or to a possible sequencing error, we have analysed the diverging zone of this ORF in three strains and have found it entirely consistent with the sequence reported as HSP150/PIR2, concluding that the divergence is probably due to a sequencing error in YJL159w. Copy…
What do you mean by transcription rate?
2013
mRNA synthesis in all organisms is performed by RNA polymerases, which work as nanomachines on DNA templates. The rate at which their product is made is an important parameter in gene expression. Transcription rate encompasses two related, yet different, concepts: the nascent transcription rate, which measures the in situ mRNA production by RNA polymerase, and the rate of synthesis of mature mRNA, which measures the contribution of transcription to the mRNA concentration. Both parameters are useful for molecular biologists, but they are not interchangeable and they are expressed in different units. It is important to distinguish when and where each one should be used. We propose that for fu…
A novel approach for the improvement of stress resistance in wine yeasts
2006
During wine production yeast cells are affected by several stress conditions that could affect their viability and fermentation efficiency. In this work we describe a novel genetic manipulation strategy designed to improve stress resistance in wine yeasts. This strategy involves modifying the expression of the transcription factor MSN2, which plays an important role in yeast stress responses. The promoter in one of the genomic copies of this gene has been replaced by the promoter of the SPI1 gene, encoding for a cell wall protein of unknown function. SPI1 is expressed at late phases of growth and is regulated by Msn2p. This modification allows self-induction of MSN2 expression. MSN2 gene tr…
Genetic manipulation of HSP26 and YHR087W stress genes may improve fermentative behaviour in wine yeasts under vinification conditions
2008
Throughout wine production yeast cells are affected by a plethora of stress conditions that compromise their ability to carry out the whole process. In recent years important knowledge about the mechanisms involved in stress response in both laboratory and wine yeast strains has been obtained. Several studies have indicated that a correlation exists between stress resistance, expression of stress response genes and fermentative behaviour. In this work we introduce several genetic manipulations in two genes induced by several stress conditions: HSP26 (which encodes a heat shock protein) and YHR087W (encoding a protein of unknown function) in two different wine yeasts, ICV16 and ICV27. These …