Search results for "yeast"
showing 10 items of 792 documents
Editorial for Special Issue “Yeast in Winemaking”
2021
Yeast in winemaking was first studied for its role in alcoholic fermentation, and has led to the publication of a huge amount of scientific articles [...]
Genetic Polymorphism in Wine Yeasts: Mechanisms and Methods for Its Detection
2017
The processes of yeast selection for using as wine fermentation starters have revealed a great phenotypic diversity both at interspecific and intraspecific level, which is explained by a corresponding genetic variation among different yeast isolates. Thus, the mechanisms involved in promoting these genetic changes are the main engine generating yeast biodiversity. Currently, an important task to understand biodiversity, population structure and evolutionary history of wine yeasts is the study of the molecular mechanisms involved in yeast adaptation to wine fermentation, and on remodeling the genomic features of wine yeast, unconsciously selected since the advent of winemaking. Moreover, the…
Characteristics and Management of Candidaemia Episodes in an Established Candida auris Outbreak
2020
The multi-resistant yeast Candida auris has become a global public health threat because of its ease to persist and spread in clinical environments, especially in intensive care units. One of the most severe manifestations of invasive candidiasis is candidaemia, whose epidemiology has evolved to more resistant non-albicansCandida species, such as C. auris. It is crucial to establish infection control policies in order to control an outbreak due to nosocomial pathogens, including the implementation of screening colonisation studies. We describe here our experience in managing a C. auris outbreak lasting more than two and a half years which, despite our efforts in establishing control measure…
Flor Yeast Diversity and Dynamics in Biologically Aged Wines
2018
International audience; Wine biological aging is characterized by the development of yeast strains that form a biofilm on the wine surface after alcoholic fermentation. These yeasts, known as flor yeasts, form a velum that protects the wine from oxidation during aging. Thirty-nine velums aged from 1 to 6 years were sampled from "Vin jaune" from two different cellars. We show for the first time that these velums possess various aspects in term of color and surface aspects. Surprisingly, the heterogeneous velums are mostly composed of one species, S. cerevisiae. Scanning electron microscope observations of these velums revealed unprecedented biofilm structures and various yeast morphologies f…
Use of autochthonous yeasts and bacteria in order to control Brettanomyces bruxellensis in wine
2017
Biocontrol strategies for the limitation of undesired microbial developments in foods and beverages represent a keystone toward the goal of more sustainable food systems. Brettanomyces bruxellensis is a wine spoilage microorganism that produces several compounds that are detrimental for the organoleptic quality of the wine, including some classes of volatile phenols. To control the proliferation of this yeast, sulfur dioxide is commonly employed, but the efficiency of this compound depends on the B. bruxellensis strain; and it is subject to wine composition and may induce the entrance in a viable, but nonculturable state of yeasts. Moreover, it can also elicit allergic reactions in humans. …
Wine microbiome : A dynamic world of microbial interactions
2015
International audience; Most fermented products are generated by a mixture of microbes. These microbial consortia perform various biological activities responsible for the nutritional, hygienic, and aromatic qualities of the product. Wine is no exception. Substantial yeast and bacterial biodiversity is observed on grapes, and in both must and wine. The diverse microorganisms present interact throughout the winemaking process. The interactions modulate the hygienic and sensorial properties of the wine. Many studies have been conducted to elucidate the nature of these interactions, with the aim of establishing better control of the two fermentations occurring during wine processing. However, …
A Crucial Role of Mitochondrial Dynamics in Dehydration Resistance in Saccharomyces cerevisiae
2021
Mitochondria are dynamic organelles as they continuously undergo fission and fusion. These dynamic processes conduct not only mitochondrial network morphology but also activity regulation and quality control. Saccharomyces cerevisiae has a remarkable capacity to resist stress from dehydration/rehydration. Although mitochondria are noted for their role in desiccation tolerance, the mechanisms underlying these processes remains obscure. Here, we report that yeast cells that went through stationary growth phase have a better survival rate after dehydration/rehydration. Dynamic defective yeast cells with reduced mitochondrial genome cannot maintain the mitochondrial activity and survival rate o…
Anhydrobiosis in yeast: cell wall mannoproteins are important for yeastSaccharomyces cerevisiaeresistance to dehydration
2016
The state of anhydrobiosis is linked with the reversible delay of metabolism as a result of strong dehydration of cells, and is widely distributed in nature. A number of factors responsible for the maintenance of organisms' viability in these conditions have been revealed. This study was directed to understanding how changes in cell wall structure may influence the resistance of yeasts to dehydration-rehydration. Mutants lacking various cell wall mannoproteins were tested to address this issue. It was revealed that mutants lacking proteins belonging to two structurally and functionally unrelated groups (proteins non-covalently attached to the cell wall, and Pir proteins) possessed significa…
Sng1 associates with Nce102 to regulate the yeast Pkh–Ypk signalling module in response to sphingolipid status
2016
International audience; All cells are delimited by biological membranes, which are consequently a primary target of stress-induced damage. Cold alters membrane functionality by decreasing lipid fluidity and the activity of membrane proteins. In Saccharomyces cerevisiae, evidence links sphingolipid homeostasis and membrane phospholipid asymmetry to the activity of the Ypk1/2 proteins, the yeast orthologous of the mammalian SGK1-3 kinases. Their regulation is mediated by different protein kinases, including the PDK1 orthologous Pkh1/2p, and requires the function of protein effectors, among them Nce102p, a component of the sphingolipid sensor machinery. Nevertheless, the mechanisms and the act…
Effect of (−)-epigallocatechin gallate at different pH conditions on enteric viruses.
2017
Epigallocatechin gallate (EGCG), a flavonoid from green tea, is said to have extensive antimicrobial activity in a wide range of food spoilage or pathogenic fungi, yeast and bacteria. In this work, the antiviral activity of EGCG was assessed against hepatitis A virus (HAV) and murine norovirus (MNV), a human norovirus surrogate, at different temperatures, contact times and pH conditions by cell-culture methods. EGCG was effective in reducing the titers of HAV and MNV in a dose-dependent manner at neutral pH and 25 and 37 °C, while no effect was reported at 4 °C. HAV and MNV infectivity was completely removed after overnight treatment with EGCG at 2.5 mg/mL at 37 °C. Furthermore, results als…