Search results for "Saccharomyces cerevisiae"
showing 10 items of 738 documents
Photoaffinity Labeling and Photoaffinity Cross-Linking of Phosphofructokinase-1 from Saccharomyces cerevisiae by 8-Azidoadeninenucleotides
2001
Phosphofructokinase-1 from Saccharomyces cerevisiae is composed of four alpha- and four beta-subunits, each of them carrying catalytic and regulatory bindings sites for MgATP. In this paper, various photoaffinity labels, such as 8-azidoadenosine 5'-triphosphate, 8-azido-1,N6-ethenoadenosine 5'-triphosphate, and 8-N3-3'(2')-O-biotinyl-8-azidoadenosine 5'-triphosphate have been used to study their interaction with the enzyme in the dark and during irradiation. All nucleotidetriphosphates function as phosphate donor forming fructose 1,6-bisphosphate from fructose 6-phosphate. However, the kinetic analysis revealed distinctly differences between them. Photolabeling causes a decrease in enzyme a…
Inducible lectins with galectin properties and human IL1alpha epitopes opsonize yeast during the inflammatory response of the ascidian Ciona intestin…
2007
Studies on inducible ascidian lectins may shed light on the evolutionary emergence of cytokine functions. Here, we show that the levels of opsonins, with IL1alpha-epitopes, increase in Ciona intestinalis hemolymph as a response to an inflammatory stimulus and, in particular, to intratunic injection of lipopolysaccharide (LPS). The inflammatory agent promptly (within 4 h) enhances Ca(2+)-independent serum hemagglutinating and opsonizing activities, which are both inhibited by D-galactose and D-galactosides (alpha-lactose, N-acetyl-D-lactosamine, thio-digalactoside), suggesting that anti-rabbit erythrocyte lectins with galectin properties are involved as opsonins. Inducible galectin molecules…
Heat shock response in yeast involver changes in both transcription rates and mRNA stabilities
2011
We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25uC to 37uC. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of …
Compromised integrity of excised porcine intestinal epithelium obtained from the abattoir affects the outcome of in vitro particle uptake studies
2002
Excised porcine intestinal tissue obtained from the local abattoir was studied for its suitability to examine the uptake and transport of poly(lactic-co-glycolic acid) (PLGA) nanoparticles in Peyer's (PP) and non-Peyer's patch (NPP) tissue in vitro. Incubation of such tissue with fluorescent PLGA and polystyrene particles revealed negligible uptake into the intercellular space with no noticeable difference between PP and NPP tissue. Similarly, yeast cells, which were used as a positive control for selective uptake into PP tissue, were found in the subepithelial area of both PP and NPP tissue. Therefore we examined the morphological integrity of the tissue for the duration of the experiments…
Use of Saccharomyces cerevisiae as a whole cell system for aldol condensation in organic medium: Study of the factors affecting the biotransformation
2011
Abstract Saccharomyces cerevisiae has been employed as a whole cell catalyst for a number of asymmetric transformations. This work explores the ability of this microorganism to carry out the asymmetric aldol condensation between 4-nitrobenzaldehyde and acetone. For this purpose, lyophilized cells of the FY86 laboratory strain from stationary phase cultures were employed. This reaction shows stereoselectivity, and its progress is affected by the water concentration in the medium, temperature and the growth stage of the yeast culture. Cell lysis experiments indicate that activity responsible for this biotransformation is located in the soluble fraction.
Lysis of yeast cells by Oenococcus oeni enzymes
2000
exhibited extracellular β (1→3) glucanase activity. This activity increased when cells were cultivated with glycosidic cell-wall macromolecules. In addition, the culture supernatant of the organism effectively lysed viable or dead cells of Saccharomyces cerevisiae. This lytic activity appeared in the early stationary phase of bacterial growth. Yeast cells at the end of the log phase of growth were the most sensitive. The optimum temperature for lysis of viable yeast cells was 40°C, which is very different from the temperatures observed in enological conditions (15–20°C). Moreover, the rate of the lytic activity was significantly lower in comparison with yeast cell wall-degrading activities …
Synthesis and biological evaluation of cycloalkylidene carboxylic acids as novel effectors of Ras/Raf interaction.
2002
The protooncogenes Ras and Raf play important roles in signal transduction pathways regulated by mitogen-activated protein kinases. Mutations of Ras that arrest the protein in its active state are frequently implicated in tumor formation. We used Ras and Raf proteins in the yeast two-hybrid system to search for natural or synthesized substances capable of modulating Ras/Raf interaction by specifically binding to one of the interacting partners. We found that cycloalkylidene carboxylic acids enhanced Ras/Raf interaction by acting on the cysteine-rich domain of Raf. Several analogues of the active substance 2-cyclohexylidene propanoic acid were synthesized and the importance of the semicyclic…
Evolution of osmosensing signal transduction in Metazoa: stress-activated protein kinases p38 and JNK.
2001
Sponges (Porifera) represent the most basal branch of the Metazoa alive today. We show that two central stress-activated protein kinases involved in the osmosensing pathway, p38 mitogen-activated protein kinase (MAPK) and JNK, can complement for the ancestral MAPK Hog1 in the yeast Saccharomyces cerevisiae. S. cerevisiae mutants lacking Hog1 (hog1-Delta 1) have been complemented with the sponge SDJNK and SDp38 genes. Western blotting has revealed that, after transformation, the hog1-Delta 1+ SDJNK(sense) and hog1-Delta 1+ SDp38(sense) clones express the sponge proteins. Functional studies have demonstrated that the complemented clones grow under hyperosmotic conditions (0.6 M NaCl). Further…
Influence of the drying processes of yeasts on their volatile phenol sorption capacity in model wine.
2009
International audience; Volatile phenols, such as 4-ethylphenol, are responsible for a "horsey" smell in wine. Thus, the study of volatile phenol sorption in yeasts, and their subsequent elimination from wine, helps to optimize eco-friendly wine curative processes. Here, we compared the influences of spray drying, lyophilization and evaporative drying at low water activity on yeast, for improving the 4-ethylphenol sorption capacity in a synthetic model wine. The changes that occur in the physico-chemical characteristics of the yeast surface (surface hydrophobicity, electron-donor character and zeta potential) during these drying processes were determined to assess if any correlation exists …
A Periodic Diet that Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Healthspan
2015
SummaryProlonged fasting (PF) promotes stress resistance, but its effects on longevity are poorly understood. We show that alternating PF and nutrient-rich medium extended yeast lifespan independently of established pro-longevity genes. In mice, 4 days of a diet that mimics fasting (FMD), developed to minimize the burden of PF, decreased the size of multiple organs/systems, an effect followed upon re-feeding by an elevated number of progenitor and stem cells and regeneration. Bi-monthly FMD cycles started at middle age extended longevity, lowered visceral fat, reduced cancer incidence and skin lesions, rejuvenated the immune system, and retarded bone mineral density loss. In old mice, FMD c…