scholarly journals Diuron determines Saccharomyces cerevisiae UE-ME3 survival at beginning of exponential phase

2012 ◽  
Author(s):  
H. Tenda ◽  
I. Alves-Pereira ◽  
R. Ferreira
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Exponential Phase

An Attempt to Stimulate Mitosis in Saccharomyces cerevisiae with the Ultraviolet Luminescence from Exponential Phase Cultures of This Yeast

1985 ◽  
Vol 102 (2) ◽  
pp. 254 ◽  
Author(s):  
T. I. Quickenden ◽  
R. N. Tilbury
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Exponential Phase

scholarly journals Composition of the protoplast membrane from Saccharomyces cerevisiae

1968 ◽  
Vol 108 (3) ◽  
pp. 401-412 ◽  
Author(s):  
R. P. Longley ◽  
A. H. Rose ◽  
B. A. Knights
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Magnesium Chloride ◽  
Membrane Lipids ◽  
Dry Weight ◽  
Exponential Phase ◽  
Gas Liquid Chromatography ◽  
Liquid Chromatography Mass Spectrometry ◽  
Sterol Esters ◽  
Whole Cells ◽  
Fatty Acid Compositions

1. Protoplasts of Saccharomyces cerevisiae N.C.Y.C. 366 were prepared by incubating washed exponential-phase cells in buffered mannitol (0·8m) containing 10mm-magnesium chloride and snail gut juice (about 8mg. of protein/ml. of reaction mixture). Protoplast membranes were obtained by bursting protoplasts in ice-cold phosphate buffer (pH7·0) containing 10mm-magnesium chloride. 2. Protoplast membranes accounted for 13–20% of the dry weight of the yeast cell. They contained on a weight basis about 39% of lipid, 49% of protein, 6% of sterol (assayed spectrophotometrically) and traces of RNA and carbohydrate (glucan+mannan). 3. The principal fatty acids in membrane lipids were C16:0, C16:1 and C18:1 acids. Whole cells contained a slightly greater proportion of C16:0 and a somewhat smaller proportion of C18:1 acids. Membrane and whole-cell lipids included monoglycerides, diglycerides, triglycerides, sterols, sterol esters, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol+phosphatidylserine. Phosphorus analyses on phospholipid fractions from membranes and whole cells showed that membranes contained proportionately more phosphatidylethanolamine and phosphatidylinositol+phosphatidylserine than whole cells, which in turn were richer in phosphatidylcholine. Phospholipid fractions from membranes and whole cells had similar fatty acid compositions. 4. Membranes and whole cells contained two major and three minor sterol components. Gas–liquid chromatography, mass spectrometry and u.v. and i.r. spectra indicated that the major components were probably Δ5,7,22,24(28)-ergostatetraen-3β-ol and zymosterol. The minor sterol components in whole cells were probably episterol (or fecosterol), ergosterol and a C29 di-unsaturated sterol. 5. Defatted whole cells contained slightly more glutamate and ornithine and slightly less leucine and isoleucine than membranes. Otherwise, no major differences were detected in the amino acid compositions of defatted whole cells and membranes.

scholarly journals Genome-wide analysis of DNA turnover and gene expression in stationary-phase Saccharomyces cerevisiae

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1758-1771 ◽  
Author(s):  
A. de Morgan ◽  
L. Brodsky ◽  
Y. Ronin ◽  
E. Nevo ◽  
A. Korol ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Stationary Phase ◽  
Dna Synthesis ◽  
Exponential Phase ◽  
Yeast Cells ◽  
Genome Wide ◽  
Dna Turnover ◽  
Genomic Scale ◽  
Dna Maintenance

Exponential-phase yeast cells readily enter stationary phase when transferred to fresh, carbon-deficient medium, and can remain fully viable for up to several months. It is known that stationary-phase prokaryotic cells may still synthesize substantial amounts of DNA. Although the basis of this phenomenon remains unclear, this DNA synthesis may be the result of DNA maintenance and repair, recombination, and stress-induced transposition of mobile elements, which may occur in the absence of DNA replication. To the best of our knowledge, the existence of DNA turnover in stationary-phase unicellular eukaryotes remains largely unstudied. By performing cDNA-spotted (i.e. ORF) microarray analysis of stationary cultures of a haploid Saccharomyces cerevisiae strain, we demonstrated on a genomic scale the localization of a DNA-turnover marker [5-bromo-2′-deoxyuridine (BrdU); an analogue of thymidine], indicative of DNA synthesis in discrete, multiple sites across the genome. Exponential-phase cells on the other hand, exhibited a uniform, total genomic DNA synthesis pattern, possibly the result of DNA replication. Interestingly, BrdU-labelled sites exhibited a significant overlap with highly expressed features. We also found that the distribution among chromosomes of BrdU-labelled and expressed features deviates from random distribution; this was also observed for the overlapping set. Ty1 retrotransposon genes were also found to be labelled with BrdU, evidence for transposition during stationary phase; however, they were not significantly expressed. We discuss the relevance and possible connection of these results to DNA repair, mutation and related phenomena in higher eukaryotes.

scholarly journals The metabolic profile of lag and exponential phases of Saccharomyces cerevisiae growth changes continuously

2016 ◽  
Author(s):  
Rafael N. Bento ◽  
Miguel A. Aradhya ◽  
Valdir A. R. Semedo ◽  
Carlos E. S. Bernardes ◽  
Manuel E. M. Piedade ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metabolic Profile ◽  
Environmental Changes ◽  
Exponential Phase ◽  
Cellular Growth ◽  
Lag Phase ◽  
Continuous Increase ◽  
Flow Microcalorimetry ◽  
Growth Changes ◽  
Two Phases

AbstractCellular growth is usually separated in well-defined phases. For microorganism like Saccharomyces cerevisiae, two phases usually defined are (1) a lag phase, in which no growth is observed and cells adapt to a new environment, followed by (2) an exponential phase, in which rapid proliferation occurs. Here we investigate whether these well-defined phases are uniform. By using flow-microcalorimetry, we found that the metabolic profile of the culture is continuously changing, both in the lag and exponential phases of growth. Along the lag phase there is a continuous increase in the energy that is dissipated irreversibly as heat, while in the exponential phase the opposite occurs. We also confirm recent observations that the oxidative component of metabolism decreases along the exponential phase. Interestingly, nutrient limitation further decreases the amount of energy that is dissipated irreversibly. Altogether, this points to a picture in which cells respond rapidly to minute environmental changes by adjusting their metabolic profile.

scholarly journals Two isoforms of Saccharomyces cerevisiae glutaredoxin 2 are expressed in vivo and localize to different subcellular compartments

2002 ◽  
Vol 364 (3) ◽  
pp. 617-623 ◽  
Author(s):  
José R. PEDRAJAS ◽  
Pablo PORRAS ◽  
Emilia MARTÍNEZ-GALISTEO ◽  
C. Alicia PADILLA ◽  
Antonio MIRANDA-VIZUETE ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Exponential Phase ◽  
Start Codon ◽  
Immunochemical Analysis ◽  
Translation Product ◽  
Differential Processing ◽  
Reading Frame ◽  
Yeast Extract Peptone Dextrose ◽  
Long Form

Glutaredoxin (Grx)2 from Saccharomyces cerevisiae is a member of the two-cysteine (dithiol) subfamily of Grxs involved in the defence against oxidative stress in yeast. Recombinant yeast Grx2p, expressed in Escherichia coli, behaves as a ‘classical’ Grx that efficiently catalyses the reduction of hydroxyethyl disulphide by GSH. Grx2p also catalyses the reduction of GSSG by dihydrolipoamide with even higher efficiency. Western blot analysis of S. cerevisiae crude extracts identifies two isoforms of Grx2p of 15.9 and 11.9kDa respectively. The levels of these two isoforms reach a peak during the exponential phase of growth in normal yeast extract/peptone/dextrose ('YPD') medium, with the long form predominating over the short one. From immunochemical analysis of subcellular fractions, it is shown that both isoforms are present in mitochondria, but only the short one is detected in the cytosolic fraction. On the other hand, only the long form is prominent in microsomes. Mitochondrial isoforms should represent the processed and unprocessed products of an open reading frame (YDR513W), with a putative start codon 99bp upstream of the GRX2 start codon described thus far. These results indicate that GRX2 contains two in-frame start codons, and that translation from the first AUG results in a product that is targeted to mitochondria. The cytosolic form would result either by initiation from the second AUG, or by differential processing of one single translation product.

Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process

2002 ◽  
Vol 48 (11) ◽  
pp. 965-970 ◽  
Author(s):  
Javier Arrizon ◽  
Anne Gschaedler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Exponential Growth ◽  
Fermentation Process ◽  
Exponential Phase ◽  
Agave Tequilana ◽  
High Concentration ◽  
Additional Source ◽  
Fermentation Efficiency ◽  
Agave Juice

In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g·L–1. In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g·L–1) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.Key words: Saccharomyces cerevisiae, fermentation efficiency, nitrogen source, tequila.

The Behavior of Yeast Populations in Stracchino Cheese Packaged under Various Conditions

1996 ◽  
Vol 59 (5) ◽  
pp. 541-544 ◽  
Author(s):  
ILEANA SARAIS ◽  
DANIELA PIUSSI ◽  
VALERIA AQUILI ◽  
MARA LUCIA STECCHINI
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Lactic Acid ◽  
Shelf Life ◽  
Debaryomyces Hansenii ◽  
Exponential Phase ◽  
Life Extension ◽  
Refrigerated Storage ◽  
Yeast Growth ◽  
Candida Famata ◽  
Soft Cheese

The growth of yeasts, lactic acid bacteria, pseudomonads, and enterobacteria during the refrigerated storage of an Italian soft cheese (Stracchino) in various packaging conditions (under air, under vacuum, and in the presence of ethanol) was studied. Yeasts were found to play a significant role in cheese spoilage, producing unplesant flavors and odors and causing significant reductions in the shelf life of the paper-wrapped cheeses. Packaging under vacuum decreased the yeast growth rates and reduced the populations attained at the end of the exponential phase of growth, resulting in a shelf-life extension of the Stracchino cheese of over 28 days. A total of 129 yeasts isolates were identified according to conventional methods. The most frequently isolated yeasts were Candida colliculosa, Debaryomyces hansenii, and Candida famata. Other species encountered were Tolurospora delbrueckii, Kluyveromyces marxianus, and Saccharomyces cerevisiae

scholarly journals Resveratrol induces mitochondrial dysfunction and decreases chronological life span of Saccharomyces cerevisiae in a glucose-dependent manner

2017 ◽  
Author(s):  
Minerva Ramos-Gomez ◽  
Ivanna Karina Olivares-Marin ◽  
Melina Canizal-García ◽  
Juan Carlos González-Hernández ◽  
Gerardo M. Nava ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Oxygen Consumption ◽  
Life Span ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane ◽  
Exponential Phase ◽  
Dependent Manner ◽  
Yeast Cultures ◽  
Chronological Life Span ◽  
High Level

AbstractA broad range of health benefits have been attributed to resveratrol (RSV) supplementation in mammalian systems, including the increases in longevity. Nonetheless, despite the growing number of studies performed with RSV, the molecular mechanism by which it acts still remains unknown. Recently, it has been proposed that inhibition of the oxidative phosphorylation activity is the principal mechanism of RSV action. This mechanism suggests that RSV might induce mitochondrial dysfunction resulting in oxidative damage to cells with a concomitant decrease of cell viability and cellular life span. To prove this hypothesis, the chronological life span (CLS) of Saccharomyces cerevisiae was studied as it is accepted as an important model of oxidative damage and aging. In addition, oxygen consumption, mitochondrial membrane potential, and hydrogen peroxide (H2O2) release were measured in order to determine the extent of mitochondrial dysfunction. The results demonstrated that the supplementation of S. cerevisiae cultures with 100 μM RSV decreased CLS in a glucose-dependent manner. At high-level glucose, RSV supplementation increased oxygen consumption during the exponential phase yeast cultures, but inhibited it in chronologically aged yeast cultures. However, at low-level glucose, oxygen consumption was inhibited in yeast cultures in the exponential phase as well as in chronologically aged cultures. Furthermore, RSV supplementation promoted the polarization of the mitochondrial membrane in both cultures. Finally, RSV decreased the release of H2O2 with high-level glucose and increased it at low-level glucose. Altogether, this data supports the hypothesis that RSV supplementation decreases CLS as a result of mitochondrial dysfunction and this phenotype occurs in a glucose-dependent manner.

A physical method for separating Saccharomyces cerevisiae cells according to their ploidy

1988 ◽  
Vol 34 (9) ◽  
pp. 1102-1104 ◽  
Author(s):  
C. Vágvölgyi ◽  
J. Kucsera ◽  
L. Ferenczy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Physical Method ◽  
Exponential Phase ◽  
Yeast Cells ◽  
Selectable Markers ◽  
Ploidy Levels ◽  
Centrifugation Technique

A centrifugation technique, using genetically marked Saccharomyces cerevisiae strains, has been developed to separate Saccharomyces cerevisiae cells of different ploidy levels from exponential phase cultures. The method involves the conversion of yeast cells to protoplasts, the separation of the protoplasts on an osmotically stabilized Nycodenz gradient, and their regeneration. This type of selection may be of importance where selectable markers are not available.

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