Search results for "VISIA"

Partial purification and characterization of succinyl-CoA synthetase from Saccharomyces cerevisiae

1983

Succinyl-CoA synthetase from Saccharomyces cerevisiae was partially purified (20-fold) with a yield of 44%. The Michaelis-Menten constants were determined: Km (succinate) = 17 mM; Km (ATP) = 0.13 mM; Km (CoA) = 0.03 mM. The succinyl-CoA synthetase has a molecular weight of about 80000 dalton (as determined by polyacrylamide gradient gel electrophoresis). The pH optimum is at 6.0. During fermentation the activity of succinyl-CoA synthetase is lower than in aerobically grown yeast cells. The presence of succinyl-CoA synthetase in fermenting yeasts may be regarded as an indication for the oxidative formation of succinate. In fermenting yeast cells succinyl-CoA synthetase is repressed by glucos…

A new PCR-based method for monitoring inoculated wine fermentations.

2003

A new PCR-based method has been developed to monitor inoculated wine fermentations. The method is based on the variation in the number and position of introns in the mitochondrial gene COX1. Oligonucleotide primers homologous to the regions flanking the Saccharomyces cerevisiae COX1 introns have been designed and tested for S. cerevisiae wine yeast strain differentiation. Four primers were selected for their subsequent use in a multiplex PCR reaction and have proved to be very effective in uncovering polymorphism in natural and commercial yeast strains. An important point is that the speed and simplicity of the technique, which does not require the isolation of DNA, allows early detection o…

Diversity of Saccharomyces cerevisiae strains associated to racemes of Grillo grape variety

2020

ABSTRACT The most important oenological characteristics of high-quality sparkling wines are high content of acidity and low pH. Racemes are late-maturing grapes of Grillo variety characterized by low pH and high content of tartaric and malic acids and, due to their intrinsic characteristics, might represent an interesting technological solution to increase acid quality of base sparkling wine. To this purpose, the use of yeasts able to ferment grape must at very low pH is mandatory for the success of the process. In this work, 261 Saccharomyces cerevisiae isolated from spontaneous vinifications of Grillo grape racemes were subject to intraspecific characterization by interdelta analysis whic…

“Ecologia microbica del vitigno Grillo e selezione di ceppi ambientali di Saccharomyces cerevisiae”

2011

Use of selected indigenous yeasts from racemes of Grillo grape variety to improve the production of sparkling base wine

2019

The production of sparkling wines in Sicily is increasing considerably. The most important oenological characteristics of high quality sparkling wines are high content of acidity and low pH. In Sicily, white grape varieties such as those of the cultivar Grillo are characterized by very low concentrations of malic and tartaric acids due to hot climate and reduced rainfall typical of the production area. On the other hand, a very large amount of raceme grapes, characterized by low pH and high content of tartaric and malic acids, is largely produced by Grillo varieties. Hence, the winemaking of racemes might represent a technological solution to increase the quality of the acids in the final w…

Global analysis of the interaction between Saccharomyces cerevisiae and other Saccharomyces species of enological interest

2019

Global warming has provoked an increase in the content of sugars in grape that implies higher levels of ethanol in wines as well as unbalanced acidity, which affects the consumer perception. In addition, wine market is becoming more and more sophisticated, demanding for products with new and richer aroma profiles. Here, the solution we propose involves the use of alternative species of the Saccharomyces. Those are characterized by lower yields of ethanol than S. cerevisiae, and distinct aroma profiles potentially interesting for industry. The main problem with these yeasts is that they are easily outcompeted from the fermentative media by the action of the naturally present S. cerevisiae. T…

Genomic insights into the layers of gene regulation in yeast

2011

The model organism Saccharomyces cerevisiae has allowed the development of new functional genomics techniques devoted to the study of transcription in all its stages. With these techniques, it has been possible to find interesting new mechanisms to control gene expression that act at different levels and for different gene sets apart from the known cis-trans regulation in the transcription initiation step. Here we discuss a method developed in our laboratory, Genomic Run-On, and other new methods that have recently appeared with distinct technical features. A comparison between the datasets generated by them provides interesting genomic insights into the different layers of gene regulation …

Acid trehalase is involved in intracellular trehalose mobilization during postdiauxic growth and severe saline stress in Saccharomyces cerevisiae.

2008

The role of the acid trehalase encoded by the ATH1 gene in the yeast Saccharomyces cerevisiae is still unclear. In this work, we investigated the regulation of ATH1 transcription and found a clear involvement of the protein kinase Hog1p in the induction of this gene under severe stress conditions, such as high salt. We also detected changes in the acid trehalase activity and trehalose levels, indicating a role of the acid trehalase in intracellular trehalose mobilization. Finally, the growth analysis for different mutants in neutral and acid trehalases after high salt stress implicates acid trehalase activity in saline stress resistance.

Partial Methylation at Am100 in 18S rRNA of Baker's Yeast Reveals Ribosome Heterogeneity on the Level of Eukaryotic rRNA Modification

2014

Ribosome heterogeneity is of increasing biological significance and several examples have been described for multicellular and single cells organisms. In here we show for the first time a variation in ribose methylation within the 18S rRNA of Saccharomyces cerevisiae. Using RNA-cleaving DNAzymes, we could specifically demonstrate that a significant amount of S. cerevisiae ribosomes are not methylated at 2'-O-ribose of A100 residue in the 18S rRNA. Furthermore, using LC-UV-MS/MS of a respective 18S rRNA fragment, we could not only corroborate the partial methylation at A100, but could also quantify the methylated versus non-methylated A100 residue. Here, we exhibit that only 68% of A100 in t…

Yeast Life Span and its Impact on Food Fermentations

2019

Yeasts are very important microorganisms for food production. The high fermentative capacity, mainly of the species of the genus Saccharomyces, is a key factor for their biotechnological use, particularly to produce alcoholic beverages. As viability and vitality are essential to ensure their correct performance in industry, this review addresses the main aspects related to the cellular aging of these fungi as their senescence impacts their proper functioning. Laboratory strains of S. cerevisiae have proven a very successful model for elucidating the molecular mechanisms that control life span. Those mechanisms are shared by all eukaryotic cells. S. cerevisiae has two models of aging, replic…