Search results for "saccharomyces"
showing 10 items of 861 documents
Estudio del potencial patógeno de cepas de Saccharomyces cerevisiae aisladas de suplementos dietéticos y probióticos
2012
La levadura Saccharomyces cerevisiae es la especie más utilizada desde un punto de vista biotecnológico. Además, se emplea como suplemento dietético y como agente probiótico bajo el nombre de S. cerevisiae var. boulardii. Hasta ahora, su consumo se había considerado beneficioso por sus propiedades biofuncionales y su valor nutritivo intrínseco, y por otra parte, seguro, dado el carácter “GRAS” (de Generally Recognized As Safe) que se atribuye a esta especie de levadura; sin embargo, actualmente se considera a S. cerevisiae dentro del grupo de patógenos oportunistas emergentes de baja virulencia, capaz de causar infecciones principalmente en hospedadores inmunodeprimidos. Con el fin de conoc…
Análisis de las rutas de señalización de nutrientes en cepas vínicas de Saccharomyces cerevisiae en condiciones de vinificación
2019
Tesis doctoral presentada por Beatriz Vallejo Estará para optar al grado de Doctora por la Universitat de València.
Genome Characterization of natural Saccharomyces hybrids of biotechnological interest
2012
At present, the genus Saccharomyces comprises seven species according to their patterns of breeding. The species boundaries are not clear due to the description of several reticulate events due to introgression and hybridization. In the last decade, new natural hybrids have been described in wine and brewing, such as S. cerevisiae x S. kudriavzevii. Due to new practices in wine and beer production, together with consequences in grape properties due to climatic change, led biotechnological companies to search for new yeast strains. In this context, hybrids have become of importance to biotechnological industries because they show good fermentative performance at low temperatures and produce …
Molecular basis of amino acid metabolism of natural and industrialn Saccharomyces isolates
2022
Esta tesis doctoral está enmarcada en el proyecto europeo AROMAGENESIS (ID: 764364) titulado “Generation of new yeast strains for improved flavours and aromas in beer and wine”. El trabajo busca entender los mecanismos moleculares que gobiernan el catabolismo de amino ácidos y la producción de compuestos aromáticos fermentativos durante condiciones de fermentación vínica y la caracterización de nuevos genes relacionados al catabolismo de aminoácidos en ambientes naturales en especies del género Saccharomyces. En el capítulo 1 hemos demostrado que el gen ARO80 de las especies S. uvarum (Su) y S. kudriavzevii (Sk) inducen mayores niveles de expresión de los genes ARO9 y ARO10, implicados en e…
Nitrogen Metabolism of Saccharomyces and Non-Saccharomyces Wine Strains: Phenotypic and Genomic Characterisation
2020
S. cerevisiae is the most important yeast species for winemaking. In our study, different approaches were applied to evaluate the nitrogen requirement of a set of commercial S. cerevisiae strains. The selected high and low nitrogen demanding strains were sequenced and genomic differences were compared. Allele swapping of GCN1 gene revealed that the polymorphism of this gene is not the main reason for the nitrogen requirement differences in our strains. The cryotolerante Saccharomyces species such as S. uvarum, S. eubayanus and S. kudriavzevii are becoming more and more popular for wine making. However, the nitrogen requirements of these species is unclear. We studied the fermentation behavi…
Microbial resources and sparkling wine differentiation : state of the arts
2022
Consumers’ increasing interest in sparkling wine has enhanced the global market’s demand. The pro-technological yeasts strains selected for the formulation of microbial starter cultures are a fundamental parameter for exalting the quality and safety of the final product. Nowadays, the management of the employed microbial resource is highly requested by stakeholders, because of the increasing economic importance of this oenological sector. Here, we report an overview of the production processes of sparkling wine and the main characterisation criteria to select Saccharomyces and non-Saccharomyces strains appropriate for the preparation of commercial starter cultures dedicated to the primary a…
Regulación del factor transcripcional Whi7 y la proteinquinasa C en el proceso de Start y el checkpoint de integridad del DNA
2019
Start es el principal punto de control del ciclo celular en el que las células se comprometen a una nueva ronda de división celular. Este punto de control implica la activación irreversible de un programa transcripcional por los complejos Cdc28-Cln a través de la inactivación del represor transcripcional de Start Whi5. En este trabajo se proporcionan nuevas claves sobre cómo Whi7, una proteína relacionada a nivel de secuencia con Whi5, reprime Start. Nuestros resultados demuestran que Whi7 es un parálogo genuino de Whi5. Ambas proteínas colaboran en la represión de Start, aunque presentan diferencias importantes en su regulación que convierten a Whi7 en el represor de Start por excelencia e…
Eukaryotic rRNA Modification by Yeast 5-Methylcytosine-Methyltransferases and Human Proliferation-Associated Antigen p120.
2015
International audience; Modified nucleotide 5-methylcytosine (m(5)C) is frequently present in various eukaryotic RNAs, including tRNAs, rRNAs and in other non-coding RNAs, as well as in mRNAs. RNA: m(5)C-methyltranferases (MTases) Nop2 from S. cerevisiae and human proliferation-associated nucleolar antigen p120 are both members of a protein family called Nop2/NSUN/NOL1. Protein p120 is well-known as a tumor marker which is over-expressed in various cancer tissues. Using a combination of RNA bisulfite sequencing and HPLC-MS/MS analysis, we demonstrated here that p120 displays an RNA:m(5)C-MTase activity, which restores m(5)C formation at position 2870 in domain V of 25S rRNA in a nop2 Delta …
THE INFLUENCE OF THIAMINE IN THE FERMENTATION OF THE WINE YEASTS
2011
Due to the enzymatic equipment, the yeast cell produces alcoholic fermentation by the meaning of a zimazic complex which catalyzes in different stages the redox processes of the carbohydrates, which are able to ferment, ultimately leading to ethanol. The fermentation rate is an exponential function being influenced by the cells concentration in the development environment and the starter cultures of micro-organisms. Most of the yeast strains do ferment some substrates rich in hexosanes and oligoglucides: sucrose, maltose, raffinose, lactose and celobiose. The biomass quantity may be increased in various ways. An important aspect in the increasing of the multiplication rate of the yeast cell…
Evolutionary advantage conferred by an eukaryote-to-eukaryote gene transfer event in wine yeasts
2015
Although an increasing number of horizontal gene transfers have been reported in eukaryotes, experimental evidence for their adaptive value is lacking. Here, we report the recent transfer of a 158-kb genomic region between Torulaspora microellipsoides and Saccharomyces cerevisiae wine yeasts or closely related strains. This genomic region has undergone several rearrangements in S. cerevisiae strains, including gene loss and gene conversion between two tandemly duplicated FOT genes encoding oligopeptide transporters. We show that FOT genes confer a strong competitive advantage during grape must fermentation by increasing the number and diversity of oligopeptides that yeast can utilize as a s…