Search results for "yeast"
showing 10 items of 792 documents
Oxidative stress responses and lipid peroxidation damage are induced during dehydration in the production of dry active wine yeasts.
2009
The tolerance of the yeast Saccharomyces cerevisiae to desiccation is important for the use of this microorganism in the wine industry, since active dry wine yeast is routinely used as starter for must fermentations. Many studies have shown the complexity of the cellular effects caused by water loss, including oxidative injuries on macromolecular components. However the technological interest of yeast drying was not addressed in those studies, and the dehydration conditions were far from the industrial practice. In the present study a molecular approach was used to characterize the relevant injuring conditions during pilot plant dehydrations under two different drying temperatures (i.e., 35…
Interaction of an odorant lactone with model phospholipid bilayers and its strong fluidizing action in yeast membrane
2003
International audience; Some odorant lactones are naturally present in fruits or in fermented products; they can also be used as food additives and can be produced by microorganisms at the industrial scale by biotechnological processes. Gamma-decalactone was previously shown to have antimicrobial properties. We determined by infrared spectroscopy measurements that this compound rapidly diffused into model phospholipid bilayers (within 2 min), modifying the general physical state of a dimyristoyl-L-alpha-phosphatidylcholine (DMPC) film. In vivo, the lactone strongly increased membrane fluidity in the model yeast Yarrowia lipolytica, as evaluated by fluorescence anisotropy measurements. This …
Killer toxins in new isolates of the yeasts Hanseniaspora uvarum and Pichia kluyveri
1985
From various habitats (plant material, fruits, soil), yeasts belonging to the species of Pichia kluyveri and Hanseniaspora uvarum were isolated that showed killer activity. According to the activity spectrum against other yeasts these strains belonged to 11 different groups that were distinguishable from the killer strains K1-K10. The isoelectric points of the killer proteins were in the range of pH 3.5–3.9, the activity optimum was observed at pH 4.2–4.6. Above pH 5 and above a temperature of 25–35°C the killer proteins were inactivated.
A complete set of nascent transcription rates for yeast genes
2010
The amount of mRNA in a cell is the result of two opposite reactions: transcription and mRNA degradation. These reactions are governed by kinetics laws, and the most regulated step for many genes is the transcription rate. The transcription rate, which is assumed to be exercised mainly at the RNA polymerase recruitment level, can be calculated using the RNA polymerase densities determined either by run-on or immunoprecipitation using specific antibodies. The yeast Saccharomyces cerevisiae is the ideal model organism to generate a complete set of nascent transcription rates that will prove useful for many gene regulation studies. By combining genomic data from both the GRO (Genomic Run-on) a…
Expression levels of a filament-specific transcriptional regulator are sufficient to determine Candida albicans morphology and virulence
2009
Candida albicans , the major human fungal pathogen, undergoes a reversible morphological transition from single yeast cells to pseudohyphal and hyphal filaments (elongated cells attached end-to-end). Because typical C. albicans infections contain a mixture of these morphologies it has, for many years, been difficult to assess the relative contribution of each form to virulence. In addition, the regulatory mechanisms that determine growth in pseudohyphal and hyphal morphologies are largely unknown. To address these questions we have generated a C. albicans strain that can be genetically manipulated to grow completely in the hyphal form under non-filament-inducing conditions in vitro. This w…
ADR1 and SNF1 Mediate Different Mechanisms in Transcriptional Regulation of Yeast POT1 Gene
1994
We studied the consequences of adr1 and snf1 mutations on POT1 gene expression in different growth conditions. The results obtained reveal that ADR1 and SNF1 genes affect POT1 transcription in different ways: ADR1 has a minor role in derepression in low concentration of glucose but is essential for activation in stationary phase whereas SNF1 is essential for derepression and activation, although it does not seem to be directly involved in the molecular mechanism of activation in stationary phase.
External conditions inversely change the RNA polymerase II elongation rate and density in yeast.
2013
Elongation speed is a key parameter in RNA polymerase II (RNA pol II) activity. It affects the transcription rate, while it is conditioned by the physicochemical environment it works in at the same time. For instance, it is well-known that temperature affects the biochemical reactions rates. Therefore in free-living organisms that are able to grow at various environmental temperatures, such as the yeast Saccharomyces cerevisiae, evolution should have not only shaped the structural and functional properties of this key enzyme, but should have also provided mechanisms and pathways to adapt its activity to the optimal performance required. We studied the changes in RNA pol II elongation speed …
The Kelch protein NS1-BP interacts with alpha-enolase/MBP-1 and is involved in c-Myc gene transcriptional control
2007
Alpha-enolase is a key glycolytic enzyme that plays a functional role in several physiological processes depending on the cellular localization. The enzyme is mainly localized in the cytoplasm whereas an alternative translated form, named MBP-1, is predominantly nuclear. The MBP-1 protein has been characterized as a c-Myc promoter binding protein that negatively controls transcription. In the present study, we identified the kelch protein NS1-BP as one of the alpha-enolase/MBP-1 partners by using a yeast two-hybrid screening. Although NS1-BP has been originally described as a protein mainly localized in the nucleus, we provide evidence that NS1-BP also interacts with actin in human cells, a…
DNA chips for yeast biotechnology. The case of wine yeasts.
2002
The yeast Saccharomyces cerevisiae is one of the most popular model organisms. It was the first eukaryote whose genome was sequenced. Since then many functional analysis projects have tried to find the function of many genes and to understand its metabolism in a holistic way. Apart from basic science this microorganism is of great interest in several biotechnology processes, such as winemaking. Only global studies of the cell as a whole can help us to understand many of the technical problems facing winemaking. DNA chip technology is one of the most promising tools for the analysis of cell physiology. Yeast has been the model organism for the development of this technique. Many of the studi…
A genomic view of mRNA turnover in yeast
2011
The steady-state mRNA level is the result of two opposing processes: transcription and degradation; both of which can provide important points to regulate gene expression. In the model organism yeast Saccharomyces cerevisiae, it is now possible to determine, at the genomic level, the transcription and degradation rates, as well as the mRNA amount, using DNA chip or parallel sequencing technologies. In this way, the contribution of both rates to individual and global gene expressions can be analysed. Here we review the techniques used for the genomic evaluation of the transcription and degradation rates developed for this yeast, and we discuss the integration of the data obtained to fully an…