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Sturm M.E.,Instituto Nacional de Tecnologia Agropecuaria | Arroyo-Lopez F.N.,CSIC - Instituto de la Grasa | Garrido-Fernandez A.,CSIC - Instituto de la Grasa | Querol A.,Institute Agroquimica Y Tecnologia Of Los Alimentos | And 5 more authors.
International Journal of Food Microbiology | Year: 2014

The present study uses a probabilistic model to determine the growth/no growth interfaces of the spoilage wine yeast Dekkera bruxellensis CH29 as a function of ethanol (10-15%, v/v), pH (3.4-4.0) and free SO2 (0-50mg/l) using time (7, 14, 21 and 30days) as a dummy variable. The model, built with a total of 756 growth/no growth data obtained in a simile wine medium, could have application in the winery industry to determine the wine conditions needed to inhibit the growth of this species. Thereby, at 12.5% of ethanol and pH3.7 for a growth probability of 0.01, it is necessary to add 30mg/l of free SO2 to inhibit yeast growth for 7days. However, the concentration of free SO2 should be raised to 48mg/l to achieve a probability of no growth of 0.99 for 30days under the same wine conditions. Other combinations of environmental variables can also be determined using the mathematical model depending on the needs of the industry. © 2013 Elsevier B.V.


Perez-Torrado R.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Gonzalez S.S.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Combina M.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Combina M.,Instituto Nacional de Tecnologia Agropecuaria | And 3 more authors.
International Journal of Food Microbiology | Year: 2015

Saccharomyces cerevisiae plays a main role in the winemaking process, although other species, like Saccharomyces uvarum or Saccharomyces paradoxus, have been associated with must fermentations. It has been reported in recent years, that yeast hybrids of different Saccharomyces species might be responsible for wine productions. Although S. cerevisiae× Saccharomyces kudriavzevii hybrids have been well studied, very little attention has been paid to S. cerevisiae× S. uvarum hybrids. In this work we characterized the genomic composition of S6U, a widely used commercial S. cerevisiae× S. uvarum yeast hybrid isolated in wine fermentations containing one copy of the genome of each parental species, which suggests a relatively recent hybridization event. We also studied its performance under diverse enological conditions. The results show enhanced performance under low temperature enological conditions, increased glycerol production, lower acetic acid production and increased production of interesting aroma compounds. We also examined the transcriptomic response of the S6U hybrid strain compared with the reference species under enological conditions. The results show that although the hybrid strain transcriptome is more similar to S. uvarum than to S. cerevisiae, it presents specifically regulated genes involved in stress response, lipids and amino acid metabolism. The enological performance and aroma profile of this S. cerevisiae× S. uvarum hybrid makes it a good candidate for participating in winemaking, especially at low temperatures. cerevisiae x S. uvarum yeast maintain the genomes from both parents equally. uvarum than S. cerevisiae (genes involved in stress response, lipids and aminoacid metabolism). cerevisiae x S. uvarum hybrid strain S6U seems better adapted to low and intermediate temperature fermentative conditions. © 2015 Elsevier B.V.


Combina M.,Instituto Nacional de Tecnologia Agropecuaria | Combina M.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Perez-Torrado R.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Tronchoni J.,Institute Agroquimica Y Tecnologia Of Los Alimentos | And 2 more authors.
International Journal of Food Microbiology | Year: 2012

The species Saccharomyces cerevisiae plays a predominant role in the wine making process. However, other species have been associated with must fermentation, such as Saccharomyces uvarum (Saccharomyces bayanus var. uvarum) or Saccharomyces paradoxus. Recently, yeast hybrids of different Saccharomyces species have also been reported as responsible for wine production. Yeast hybrids between the species S. cerevisiae×. S. kudriavzevii isolated in wine fermentations show enhanced performance in low temperature enological conditions and increased production of interesting aroma compounds. In this work, we have studied the transcriptomic response in enological conditions of a S. cerevisiae×. S. kudriavzevii hybrid strain and compared it with the reference species of S. cerevisiae and S. kudriavzevii. The results show that the hybrid strain presents an up-regulation of genes belonging to functional group translation and amino-acid metabolism. Moreover, key genes related to cold stress and production of glycerol and aroma compounds were also up-regulated. While some genes inherited regulation patterns from one of the parents, most of the up-regulated genes presented a new gene expression pattern, probably generated during the hybridization and adaptation process. © 2012 Elsevier B.V..


Tronchoni J.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Medina V.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Guillamon J.M.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Querol A.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Perez-Torrado R.,CSIC - Institute of Agricultural Chemistry and Food Technology
BMC Genomics | Year: 2014

Background: Comparative transcriptomics and functional studies of different Saccharomyces species have opened up the possibility of studying and understanding new yeast abilities. This is the case of yeast adaptation to stress, in particular the cold stress response, which is especially relevant for the food industry. Since the species Saccharomyces kudriavzevii is adapted to grow at low temperatures, it has been suggested that it contains physiological adaptations that allow it to rapidly and efficiently acclimatise after cold shock. Results: In this work, we aimed to provide new insights into the molecular basis determining this better cold adaptation of S. kudriavzevii strains. To this end, we have compared S. cerevisiae and S. kudriavzevii transcriptome after yeast adapted to cold shock. The results showed that both yeast mainly activated the genes related to translation machinery by comparing 12°C with 28°C, but the S. kudriavzevii response was stronger, showing an increased expression of dozens of genes involved in protein synthesis. This suggested enhanced translation efficiency at low temperatures, which was confirmed when we observed increased resistance to translation inhibitor paromomycin. Finally, 35S-methionine incorporation assays confirmed the increased S. kudriavzevii translation rate after cold shock. Conclusions: This work confirms that S. kudriavzevii is able to grow at low temperatures, an interesting ability for different industrial applications. We propose that this adaptation is based on its enhanced ability to initiate a quick, efficient translation of crucial genes in cold adaptation among others, a mechanism that has been suggested for other microorganisms. © 2014 Tronchoni et al.


Llopis S.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Querol A.,Institute Agroquimica Y Tecnologia Of Los Alimentos | Heyken A.,Leibniz Institute for Natural Product Research and Infection Biology | Hube B.,Leibniz Institute for Natural Product Research and Infection Biology | And 4 more authors.
BMC Genomics | Year: 2012

Background: In recent years an increasing number of yeast infections in humans have been related to certain clinical isolates of Saccharomyces cerevisiae. Some clinical strains showed in vivo and in vitro virulence traits and were able to cause death in mice whereas other clinical strains were avirulent.Results: In this work, we studied the transcriptional profiles of two S. cerevisiae clinical strains showing virulent traits and two control non-virulent strains during a blood incubation model and detected a specific transcriptional response of clinical strains. This response involves an mRNA levels increase of amino acid biosynthesis genes and especially oxidative stress related genes. We observed that the clinical strains were more resistant to reactive oxygen species in vitro. In addition, blood survival of clinical isolates was high, reaching similar levels to pathogenic Candida albicans strain. Furthermore, a virulent strain mutant in the transcription factor Yap1p, unable to grow in oxidative stress conditions, presented decreased survival levels in human blood compared with the wild type or YAP1 reconstituted strain.Conclusions: Our data suggest that this enhanced oxidative stress response in virulent clinical isolates, presumably induced in response to oxidative burst from host defense cells, is important to increase survival in human blood and can help to infect and even produce death in mice models. © 2012 Llopis et al.; licensee BioMed Central Ltd.

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