Search results for "SIAE"
showing 10 items of 787 documents
Acetaldehyd als Indicator f�r die Regulation von Atmung und G�rung bei der aeroben Verg�rung von Glucose durch Saccharomyces cerevisiae
1971
Wahrend der aeroben Vergarung von Glucose wurde die Konzentration von Acetaldehyd im Garmedium uber den gesamten Garablauf bei mehreren Stammen von Saccharomyces cerevisiae verfolgt. Die Aldehydkonzentration weist bei Glucosekonzentrationen zwischen 5 und 20% zwei Maxima auf. Damit ist der Konzentrationsverlauf von Acetaldehyd aerob wesentlich anders als bei der anaeroben Garung, mit nur einem meist niedrigen Maximum. 10-3 M Azid hemmt die Bildung von Acetaldehyd ganz oder weitgehend. Das deutet auf die Funktion bzw. Synthese der Cytochrome, die in Gegenwart von Sauerstoff offensichtlich auch bei hohen Glucosekonzentrationen nicht vollstandig reprimiert werden. Der durch die Atmung bedingte…
Dehydration of yeast: Changes in the intracellular content of Hsp70 family proteins
2008
Abstract Yeast is known to experience in natural and industrial conditions cycles of dehydration–rehydration. Several molecular mechanisms can be triggered in response to this and other environmental stressors and to rescue yeast cells of the cytotoxic effect. Since heat shock proteins constitute one of the most important systems of the response to stress we studied whether the pre-induced major stress protein, Hsp70, can cope with yeast cell drying. To induce Hsp70 expression the cells of two yeast species, Saccharomyces cerevisiae and Debaryomyces hansenii , were subjected to non-lethal heat shock. It was found that during yeast culture growth Hsp70 accumulation occurred at the exponentia…
Identification of highly conserved genes: SNZ and SNO in the marine sponge Suberites domuncula: their gene structure and promoter activity in mammali…
2001
Abstract Recently, we reported that cells from the sponge Suberites domuncula respond to ethylene with an increase in intracellular Ca 2+ level [Ca 2+ ] i , and with an upregulation of the expression of (at least) two genes, a Ca 2+ /calmodulin-dependent protein kinase and the potential ethylene-responsive gene, termed SDSNZERR (A. Krasko, H.C. Schroder, S. Perovic, R. Steffen, M. Kruse, W. Reichert, I.M. Muller, W.E.G. Muller, J. Biol. Chem. 274 (1999)). Here, we describe for the first time that also mammalian (3T3) cells respond to ethylene, generated by ethephon, with an immediate and transient, strong increase in [Ca 2+ ] i . Next, the promoter for the sponge SDSNZERR gene was isolated …
Biochemistry and Molecular Biology of DNA Replication in Yeast
1985
For the past two decades, the study of the mechanism of DNA replication has been focused mainly on the chromosomes of the simple prokaryotes and their viruses (1). The complexity of the eukaryotic genome and multiple levels of control during the replication of eukaryotic chromosomes have until recently prevented similar studies. In recent years, a lower eukaryote, the yeast Saccharomyces cerevisiae, has become a major focus of efforts in molecular biology. In this chapter, I will briefly review accomplishments in this area. Yeast is an ideal model system for studies on the structure and replication of the eukaryotic chromosome. Yeast cells are easy to grow and study biochemically. Genetic a…
Formation of l(-)malate by Saccharomyces cerevisiae during fermentation
1988
When grown in a synthetic medium most of the 51 strains of the genera Saccharomyces, Saccharomycodes, Zygosaccharomyces and Schizosaccharomyces investigated formed l-malate during fermentation. The quantity varied between 0.1 and 2.6 g malate per liter. Two strains of Saccharomyces cerevisiae synthesized malate at a rate of about 1.5 g/l. Malate was liberated during the growth phase and not metabolized during the stationary phase. Optimum malate formation was observed at a sugar concentration of about 20% (w/v), at pH 5 and at suboptimal nitrogen concentrations of less than 300 mg N/liter. Of the amino acids aspartate and glutamate were most favourable. If ammonium salts were used as the ni…
Enhanced fermentative capacity of yeasts engineered in storage carbohydrate metabolism.
2014
During yeast biomass production, cells are grown through several batch and fed-batch cultures on molasses. This industrial process produces several types of stresses along the process, including thermic, osmotic, starvation, and oxidative stress. It has been shown that Saccharomyces cerevisiae strains with enhanced stress resistance present enhanced fermentative capacity of yeast biomass produced. On the other hand, storage carbohydrates have been related to several types of stress resistance in S. cerevisiae. Here we have engineered industrial strains in storage carbohydrate metabolism by overexpressing the GSY2 gene, that encodes the glycogen synthase enzyme, and deleting NTH1 gene, that …
Protection of living yeast cells by micro-organized shells of natural polyelectrolytes
2015
International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…
On the fermentative behavior of auxotrophic strains of Saccharomyces cerevisiae
2014
Background: The selection of new yeast strains could lead to improvements in bioethanol production. Here, we have studied the fermentative capacity of different auxotrophic mutants of Saccharomyces cerevisiae, which are routinely used as hosts for the production of heterologous proteins. It has recently been found that these strains exhibit physiological alterations and peculiar sensitivities with respect to the parental prototrophic strains from which they derive. In this work the performance of auxotrophic S. cerevisiae CEN.PK strains was compared to the corresponding prototrophic strain, to S. cerevisiae T5bV, a strain isolated from grape must and to another auxotrophic strain, S. cerevi…
Thermotolerance in Saccharomyces cerevisiae is linked to resistance to anhydrobiosis
2014
Abstract We have demonstrated that a thermotolerant yeast strain ( Saccharomyces cerevisiae TS1) is much more resistant to dehydration–rehydration treatments than a mesophilic strain of S. cerevisiae . Yeast resistance to dehydration–rehydration was found to be similar in cells from exponential and stationary growth phases. Under controlled rehydration conditions involving gradual rehydration in water vapour, yeast cell viability was maintained at 90–95%. When S. cerevisiae TS1 cells were pre-grown at 37 °C and then dried, controlled rehydration lead to restoration of plasma membrane integrity, indicating important differences in cell envelope architechture of mesophilic and thermotolerant …
Validación funcional de extractos polifenólicos de cacao mediante ensayos in vivo con organismos modelo
2016
Los polifenoles son los principales antioxidantes de la dieta y a ellos se les atribuyen múltiples propiedades beneficiosas, como la prevención de enfermedades cardiovasculares, tumorales y degenerativas, que pueden aparecer como consecuencia del estrés oxidativo. El cacao representa una fuente interesante de polifenoles en la dieta, dado su amplio consumo y su riqueza en estos compuestos bioactivos. La actividad antioxidante de los polifenoles en general, y en concreto de los polifenoles del cacao, ha sido ampliamente evaluada in vitro. Sin embargo, los ensayos in vitro no tienen en cuenta aspectos fundamentales en organismos vivos como son la biodisponibilidad y metabolismo, ni proporcion…