Search results for "Saccharomyce"
showing 10 items of 875 documents
Identification of a 49-kDa hydrophobic cell wall mannoprotein present in velum yeast which may be implicated in velum formation
2000
Analysis of velum-forming yeast cell wall components released by beta-1,3-glucanase treatment were compared with those of a non velum-forming yeast. SDS-PAGE electrophoresis and Western blotting with ConA-peroxidase staining of mannoproteins allowed us to identify a 49-kDa mannoprotein present in the cell wall of the velum-forming yeast and hardly visible in the control. The cell wall nature of this protein was confirmed by labelling with the non-permeable sulfosuccinimydiyl-6-(biotinamido)hexanoate reagent. A partial purification of this mannoprotein by anion exchange HPLC followed by surface hydrophobicity determination revealed that the fraction containing the 49-kDa mannoprotein was the…
Cell volume homeostatically controls the rDNA repeat copy number and rRNA synthesis rate in yeast
2019
AbstractThe adjustment of transcription and translation rates to variable needs is of utmost importance for the fitness and survival of living cells. We have previously shown that the global transcription rate for RNA polymerase II is regulated differently in cells presenting symmetrical or asymmetrical cell division. The budding yeast Saccharomyces cerevisiae adopts a particular strategy to avoid that the smaller daughter cells increase their total mRNA concentration with every generation. The global mRNA synthesis rate lowers with a growing cell volume, but global mRNA stability increases. In this paper, we address what the solution is to the same theoretical problem for the RNA polymeras…
Convergent adaptation of Saccharomyces uvarum to sulfite, an antimicrobial preservative widely used in human-driven fermentations
2021
Different species can find convergent solutions to adapt their genome to the same evolutionary constraints, although functional convergence promoted by chromosomal rearrangements in different species has not previously been found. In this work, we discovered that two domesticated yeast species, Saccharomyces cerevisiae, and Saccharomyces uvarum, acquired chromosomal rearrangements to convergently adapt to the presence of sulfite in fermentation environments. We found two new heterologous chromosomal translocations in fermentative strains of S. uvarum at the SSU1 locus, involved in sulfite resistance, an antimicrobial additive widely used in food production. These are convergent events that …
Influence of cell-cell contact between L. thermotolerans and S. cerevisiae on yeast interactions and the exo-metabolome
2019
International audience; Sequential fermentation of grape must inoculated with L. thermotolerans and then S. cerevisiae 24 h later (typical wine-making practice) was conducted with or without cell-cell contact between the two yeast species. We monitored cell viability of the two species throughout fermentation by flow cytometry. The cell viability of S. cerevisiae decreased under both conditions, but the decrease was greater if there was cell-cell contact. An investigation of the nature of the interactions showed competition between the two species for nitrogen compounds, oxygen, and must sterols. Volatile-compound analysis showed differences between sequential and pure fermentation and that…
FICC-Seq: a method for enzyme-specified profiling of methyl-5-uridine in cellular RNA.
2019
AbstractMethyl-5-uridine (m5U) is one the most abundant non-canonical bases present in cellular RNA, and in yeast is found at position U54 of tRNAs where modification is catalysed by the methyltransferase Trm2. Although the mammalian enzymes that catalyse m5U formation are yet to be identified via experimental evidence, based on sequence homology to Trm2, two candidates currently exist, TRMT2A and TRMT2B. Here we developed a genome-wide single-nucleotide resolution mapping method, Fluorouracil-Induced-Catalytic-Crosslinking-Sequencing (FICC-Seq), in order to identify the relevant enzymatic targets. We demonstrate that TRMT2A is responsible for the majority of m5U present in human RNA, and t…
Automatic Biological Cell Counting Using a Modified Gradient Hough Transform
2017
AbstractWe present a computational method for pseudo-circular object detection and quantitative characterization in digital images, using the gradient accumulation matrix as a basic tool. This Gradient Accumulation Transform (GAT) was first introduced in 1992 by Kierkegaard and recently used by Kaytanli & Valentine. In the present article, we modify the approach by using the phase coding studied by Cicconet, and by adding a “local contributor list” (LCL) as well as a “used contributor matrix” (UCM), which allow for accurate peak detection and exploitation. These changes help make the GAT algorithm a robust and precise method to automatically detect pseudo-circular objects in a microscop…
Approaches to study yeast cell aging and death
2014
For millennia, yeast has been exploited to obtain fermentation products, such as foods and beverages. For c. 50 years, yeast has been an established model organism for basic and applied research, and more specifically, for c. 15 years, this unicellular organism has been applied to dissect molecular mechanisms of cell aging and programmed cell death. In this review, we present an overview of approaches to study cell aging and death in yeast, including lifespan assessments, calorie restriction, cell viability, survival, and death markers.
Purine Auxotrophic Starvation Evokes Phenotype Similar to Stationary Phase Cells in Budding Yeast
2021
Purine auxotrophy is an abundant trait among eukaryotic parasites and a typical marker for many budding yeast strains. Supplementation with an additional purine source (such as adenine) is necessary to cultivate these strains. If not supplied in adequate amounts, purine starvation sets in. We explored purine starvation effects in a model organism, a budding yeast Saccharomyces cerevisiae ade8 knockout, at the level of cellular morphology, central carbon metabolism, and global transcriptome. We observed that purine-starved cells stopped their cycle in G1/G0 state and accumulated trehalose, and the intracellular concentration of AXP decreased, but adenylate charge remained stable. Cells becam…
Iron regulatory mechanisms in Saccharomyces cerevisiae
2020
Iron is an essential micronutrient for all eukaryotic organisms because it participates as a redox cofactor in many cellular processes. However, excess iron can damage cells since it promotes the generation of reactive oxygen species. The budding yeast Saccharomyces cerevisiae has been used as a model organism to study the adaptation of eukaryotic cells to changes in iron availability. Upon iron deficiency, yeast utilizes two transcription factors, Aft1 and Aft2, to activate the expression of a set of genes known as the iron regulon, which are implicated in iron uptake, recycling and mobilization. Moreover, Aft1 and Aft2 activate the expression of Cth2, an mRNA-binding protein that limits t…
Molecular evolution in yeast of biotechnological interest
2003
The importance of yeast in the food and beverage industries was only realized about 1860, when the role of these organisms in food manufacture became evident. Since they grow on a wide range of substrates and can tolerate extreme physicochemical conditions, yeasts, especially the genera Saccharomyces and Kluyveromyces, have been applied to many industrial processes, Industrial strains of these genera are highly specialized organisms that have evolved to utilize a range of environments and ecological niches to their full potential. This adaptation is called "domestication". This review describes the phylogenetic relationships among Saccharomyces and Kluyveromyces species and the different me…