Search results for "Saccharomyce"

2020

Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance inS.cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a disti…

Network motif-based analysis of regulatory patterns in paralogous gene pairs

2020

Current high-throughput experimental techniques make it feasible to infer gene regulatory interactions at the whole-genome level with reasonably good accuracy. Such experimentally inferred regulatory networks have become available for a number of simpler model organisms such as S. cerevisiae, and others. The availability of such networks provides an opportunity to compare gene regulatory processes at the whole genome level, and in particular, to assess similarity of regulatory interactions for homologous gene pairs either from the same or from different species. We present here a new technique for analyzing the regulatory interaction neighborhoods of paralogous gene pairs. Our central focu…

Flipping of alkylated DNA damage bridges base and nucleotide excision repair

2009

Alkyltransferase-like proteins (ATLs) share functional motifs with the cancer chemotherapy target O6-alkylguanine-DNA alkyltransferase (AGT) and paradoxically protect cells from the biological effects of DNA alkylation damage, despite lacking the reactive cysteine and alkyltransferase activity of AGT. Here we determine Schizosaccharomyces pombe ATL structures without and with damaged DNA containing the endogenous lesion O6-methylguanine or cigarette-smoke-derived O6-4-(3-pyridyl)-4-oxobutylguanine. These results reveal non-enzymatic DNA nucleotide flipping plus increased DNA distortion and binding pocket size compared to AGT. Our analysis of lesion-binding site conservation identifies new A…

Surviving the heat: heterogeneity of response inSaccharomyces cerevisiaeprovides insight into thermal damage to the membrane

2015

Environmental heat stress impacts on the physiology and viability of microbial cells with concomitant implications for microbial activity and diversity. Previously, it has been demonstrated that gradual heating of Saccharomyces cerevisiae induces a degree of thermal resistance, whereas a heat shock results in a high level of cell death. Here, we show that the impact of exogenous nutrients on acquisition of thermal resistance differs between strains. Using single-cell methods, we demonstrate the extent of heterogeneity of the heat-stress response within populations of yeast cells and the presence of subpopulations that are reversibly damaged by heat stress. Such cells represent potential for…

Expression profile of genes involved in hydrogen sulphide liberation by Saccharomyces cerevisiae grown under different nitrogen concentrations

2009

AbstractThe present work aims to elucidate molecular mechanisms underlying hydrogen sulphide production in S. cerevisiae associated to nitrogen deficiency. To assess, at a genome-wide level, how the yeast strain adapted to the progressive nitrogen depletion and to nitrogen re-feeding, gene expression profiles were evaluated during fermentation at different nitrogen concentrations, using the DNA array technology. The results showed that most MET genes displayed higher expression values at the beginning of both control and N-limiting fermentation, just before the time at which the release of sulphide was observed. MET genes were downregulated when yeast stopped growing which could associate M…

Antiproliferative activity of green, black tea and olive leaves polyphenols subjected to biosorption and in vitro gastrointestinal digestion in Caco-…

2020

Olive (Olea europaea L.) leaves and tea (Camellia sinensis) are rich sources of bioactive compounds, especially polyphenols. Our previous studies have evidenced the potential use of Saccharomyces cerevisiae as a natural delivery system for these antioxidants and a means to improve their bioaccessibility in the human gut. In the present work, the antiproliferative effect of green tea (GT), black tea (BT) and olive leaves (OL) infusions and suspensions of S. cerevisiae were evaluated, for the first time, in human colon cancer cells (Caco-2) after biosorption and in vitro gastrointestinal digestion. The bioaccessible fractions (BF) were not overtly cytotoxic, not affecting cell viability. ROS …

2017

Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN) deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non-Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non-Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With…

Post-Transcriptional Regulation of Iron Homeostasis in Saccharomyces cerevisiae

2013

Iron is an essential micronutrient for all eukaryotic organisms because it participates as a redox cofactor in a wide variety of biological processes. Recent studies in Saccharomyces cerevisiae have shown that in response to iron deficiency, an RNA-binding protein denoted Cth2 coordinates a global metabolic rearrangement that aims to optimize iron utilization. The Cth2 protein contains two Cx8Cx5Cx3H tandem zinc fingers (TZFs) that specifically bind to adenosine/uridine-rich elements within the 3' untranslated region of many mRNAs to promote their degradation. The Cth2 protein shuttles between the nucleus and the cytoplasm. Once inside the nucleus, Cth2 binds target mRNAs and stimulate…

Transcriptional Response of Saccharomyces cerevisiae to Different Nitrogen Concentrations during Alcoholic Fermentation▿ †

2007

Gene expression profiles of a wine strain of Saccharomyces cerevisiae PYCC4072 were monitored during alcoholic fermentations with three different nitrogen supplies: (i) control fermentation (with enough nitrogen to complete sugar fermentation), (ii) nitrogen-limiting fermentation, and (iii) the addition of nitrogen to the nitrogen-limiting fermentation (refed fermentation). Approximately 70% of the yeast transcriptome was altered in at least one of the fermentation stages studied, revealing the continuous adjustment of yeast cells to stressful conditions. Nitrogen concentration had a decisive effect on gene expression during fermentation. The largest changes in transcription profiles were o…

Caracterización enológica y molecular de híbridos naturales y artificiales entre las especies saccharomyces cerevisiae y saccharomyces kudriavzevii

2018

La industria enológica debe dar respuesta a las nuevas demandas del consumidor, así como responder ante los cambios en la materia prima(mosto) debidos al cambio climático, de gran repercusión en la calidad y aceptación del vino. Para ello se exigen cambios en las prácticas enológicas como el desarrollo de cultivos iniciadores de levaduras adaptadas a las nuevas condiciones de fermentación como son las bajas temperaturas para obtener vinos más aromáticos o el desarrollo de levaduras que produzcan más aromas, mayor concentración de glicerol y menos etanol. S. cerevisiae se ha descrito como la especie predominante en la fermentación alcohólica; sin embargo, otras especies del género Saccharomy…