Search results for "VISIA"
showing 10 items of 764 documents
AtCCS is a functional homolog of the yeast copper chaperone Ccs1/Lys7
2005
AbstractIn plant chloroplasts two superoxide dismutase (SOD) activities occur, FeSOD and Cu/ZnSOD, with reciprocal regulation in response to copper availability. This system presents a unique model to study the regulation of metal-cofactor delivery to an organelle. The Arabidopsis thaliana gene AtCCS encodes a functional homolog to yeast Ccs1p/Lys7p, a copper chaperone for SOD. The AtCCS protein was localized to chloroplasts where it may supply copper to the stromal Cu/ZnSOD. AtCCS mRNA expression levels are upregulated in response to Cu-feeding and senescence. We propose that AtCCS expression is regulated to allow the most optimal use of Cu for photosynthesis.
Anhydrobiosis in Yeasts: Changes in Mitochondrial Membranes Improve the Resistance of Saccharomyces cerevisiae Cells to Dehydration–Rehydration
2019
Anhydrobiosis is a unique state of live organisms in which their metabolism is temporary reversibly suspended as the result of strong dehydration of their cells. This state is widely used currently during large-capacity production of active dry baker&rsquo
Changes in Energy Status of Saccharomyces cerevisiae Cells During Dehydration and Rehydration
2021
Anhydrobiosis is the state of life when cells are exposed to waterless conditions and gradually cease their metabolism. In this study, we determined the sequence of events in Saccharomyces cerevisiae energy metabolism during processes of dehydration and rehydration. The intensities of respiration and acidification of the medium, the amounts of phenyldicarbaundecaborane (PCB−) bound to yeast membranes, and the capabilities of cells to accumulate K+ were assayed using an electrochemical monitoring system, and the intracellular content of ATP was measured using a bioluminescence assay. Mesophilic, semi-resistant to desiccation S. cerevisiae strain 14 and thermotolerant, very resistant to desic…
Impact of Nitrogen Addition on Wine Fermentation by S. cerevisiae Strains with Different Nitrogen Requirements
2021
In modern oenology, supplementation of nitrogen sources is an important strategy to prevent sluggish or stuck fermentation. The present study thoroughly determined the effect of nitrogen addition timing and nitrogen source type on fermentation kinetics and aroma production, carried out by yeast strains with low and high nitrogen requirements. The results revealed that yeast strains with different nitrogen requirements have divergent reactions to nitrogen addition. Nitrogen addition clearly shortened the fermentation duration, especially for the high-nitrogen-demanding yeast strain. Nitrogen addition at 1/3 fermentation was the most effective in terms of fermentation activity, nitrogen assim…
Involvement of osmotic cell shrinkage on the proton extrusion rate in Saccharomyces cerevisiae
2001
Saccharomyces cerevisiae has been subjected to hyperosmotic shocks by using permeating (sorbitol, xylitol, glycerol, NaCl) and nonpermeating (PEG 600) solutes. The proton extrusion rate decreased as the osmotic pressure increased, whichever solute was used. However, the total inhibition of the cellular H+ extrusion depended on the solute used. A total inhibition was observed at about 20 MPa with glycerol, xylitol and sorbitol. With PEG 600, a total inhibition of extracellular acidification was obtained at 8.5 MPa. NaCl, with an extracellular pressure of 37.8 MPa (near saturation), did not completely inhibit the extracellular acidification. These results showed that the total inhibition of p…
Kinetic studies on protoporphyrinogen oxidase inhibition by diphenyl ether herbicides
1991
Diphenyl ethers (DPEs) and related herbicides are powerful inhibitors of protoporphyrinogen oxidase, an enzyme involved in the biosynthesis of haems and chlorophylls. The inhibition kinetics of protoporphyrinogen oxidase of various origins by four DPEs, (methyl)-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen and its methyl ester, acifluorfen-methyl), methyl-5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-chlorobenzoate (LS 820340) and methyl-5-[2-chloro-5-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (RH 5348), were studied. The inhibitions of the enzymes from maize (Zea mays) mitochondrial and etiochloroplastic membranes and mouse liver mitochondrial membranes were com…
An STE12 gene identified in the mycorrhizal fungus Glomus intraradices restores infectivity of a hemibiotrophic plant pathogen
2009
International audience; * • Mechanisms of root penetration by arbuscular mycorrhizal (AM) fungi are unknown and investigations are hampered by the lack of transformation systems for these unculturable obligate biotrophs. Early steps of host infection by hemibiotrophic fungal phytopathogens, sharing common features with those of AM fungal colonization, depend on the transcription factor STE12. * • Using degenerated primers and rapid amplification of cDNA ends, we isolated the full-length cDNA of an STE12-like gene, GintSTE, from Glomus intraradices and profiled GintSTE expression by real-time and in situ RT-PCR. GintSTE activity and function were investigated by heterologous complementation …
Molecular determinants of the Arabidopsis AKT1 K+ channel ionic selectivity investigated by expression in yeast of randomly mutated channels
1999
International audience; The Avabidopsis thaliana K+ channel AKT1 was expressed in a yeast strain defective for K+ uptake at low K+ concentrations (<3 mM). Besides restoring K+ transport in this strain, AKT1 expression increased its tolerance to salt (NaCl or LiCl), whatever the external K+ concentration used (50 mu M, 5 mM, or 50 mM), We took advantage of the latter phenomenon for screening a library of channels randomly mutated in the region that shares homologies with the pore forming domain (the so-called P domain) of animal K+ channels (Shaker family). Cassette mutagenesis was performed using a degenerate oligonucleotide that was designed to ensure, theoretically, a single mutation per …
Purine auxotrophy: Possible applications beyond genetic marker
2019
Exploring new drug candidates or drug targets against many illnesses is necessary as "traditional" treatments lose their effectivity. Cancer and sicknesses caused by protozoan parasites are among these diseases. Cell purine metabolism is an important drug target. Theoretically, inhibiting purine metabolism could stop the proliferation of unwanted cells. Purine metabolism is similar across all eukaryotes. However, some medically important organisms or cell lines rely on their host purine metabolism. Protozoans causing malaria, leishmaniasis, or toxoplasmosis are purine auxotrophs. Some cancer forms have also lost the ability to synthesize purines de novo. Budding yeast can serve as an effect…
Use of grape racemes from Grillo cultivar to increase the acidity level of sparkling base wines produced with different Saccharomyces cerevisiae stra…
2020
The most important oenological characteristics of high-quality sparkling wines are aromatic aspect, taste persistence, perlage, high levels of acidity and low pH. Due to hot climate and reduced rainfall that characterize Sicily region, white grape varieties such as Grillo cultivar cultivated in this area are characterized by very low concentrations of malic and tartaric acids. Grillo cultivar is characterized by an intense production of raceme grapes with low pH and high content of tartaric and malic acids. These fruits possess the chemical properties useful to increase the amounts of acids in the final wines. With this in mind, the present research was carried out to test the ability of fo…