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Sample records for saccharomyces cerevisiae encodes

  1. Regulation of the Saccharomyces cerevisiae EKI1-encoded Ethanolamine Kinase by Zinc Depletion*

    OpenAIRE

    Kersting, Michael C.; CARMAN, George M.

    2006-01-01

    Ethanolamine kinase catalyzes the committed step in the synthesis of phosphatidylethanolamine via the CDP-ethanolamine branch of the Kennedy pathway. Regulation of the EKI1-encoded ethanolamine kinase by the essential nutrient zinc was examined in Saccharomyces cerevisiae. The level of ethanolamine kinase activity increased when zinc was depleted from the growth medium. This regulation correlated with increases in the CDP-ethanolamine pathway intermediates phosphoethanolamine and CDP-ethanola...

  2. YLR209c Encodes Saccharomyces cerevisiae Purine Nucleoside Phosphorylase

    OpenAIRE

    Lecoq, K; Belloc, I.; C. Desgranges; Konrad, M.; Daignan-Fornier, B

    2001-01-01

    The yeast YLR209c (PNP1) gene encodes a protein highly similar to purine nucleoside phosphorylases. This protein specifically metabolized inosine and guanosine. Disruption of PNP1 led to inosine and guanosine excretion in the medium, thus showing that PNP1 plays an important role in the metabolism of these purine nucleosides in vivo.

  3. AGT1, Encoding an ?-Glucoside Transporter Involved in Uptake and Intracellular Accumulation of Trehalose in Saccharomyces cerevisiae

    OpenAIRE

    Plourde-Owobi, Lucile; Durner, Sophie; Parrou, Jean-Luc; Wieczorke, Roman; Goma, Gerard; François, Jean

    1999-01-01

    The trehalose content in Saccharomyces cerevisiae can be significantly manipulated by including trehalose at an appropriate level in the growth medium. Its uptake is largely dependent on the expression of AGT1, which encodes an ?-glucoside transporter. The trehalose found in a tps1 mutant of trehalose synthase may therefore largely reflect its uptake from the enriched medium that was employed.

  4. Bacterial XylRs and synthetic promoters function as genetically encoded xylose biosensors in Saccharomyces cerevisiae.

    Science.gov (United States)

    Teo, Wei Suong; Chang, Matthew Wook

    2015-02-01

    Lignocellulosic biomass is a sustainable and abundant starting material for biofuel production. However, lignocellulosic hydrolysates contain not only glucose, but also other sugars including xylose which cannot be metabolized by the industrial workhorse Saccharomyces cerevisiae. Hence, engineering of xylose assimilating S. cerevisiae has been much studied, including strain optimization strategies. In this work, we constructed genetically encoded xylose biosensors that can control protein expression upon detection of xylose sugars. These were constructed with the constitutive expression of heterologous XylR repressors, which function as protein sensors, and cloning of synthetic promoters with XylR operator sites. Three XylR variants and the corresponding synthetic promoters were used: XylR from Tetragenococcus halophile, Clostridium difficile, and Lactobacillus pentosus. To optimize the biosensor, two promoters with different strengths were used to express the XylR proteins. The ability of XylR to repress yEGFP expression from the synthetic promoters was demonstrated. Furthermore, xylose sugars added exogenously to the cells were shown to regulate gene expression. We envision that the xylose biosensors can be used as a tool to engineer and optimize yeast that efficiently utilizes xylose as carbon source for growth and biofuel production. PMID:24975936

  5. Genes regulation encoding ADP/ATP carrier in yeasts Saccharomyces cerevisiae and Candida parapsilosis

    International Nuclear Information System (INIS)

    Genes encoding a mitochondrial ADP/ATP carrier (AAC) in yeast Saccharomyces cerevisiae and Candida parapsilosis were investigated. AAC2 is coding for the major AAC isoform in S. cerevisiae. We suggest that AAC2 is a member of a syn-expression group of genes encoding oxidative phosphorylation proteins. Within our previous studies on the regulation of the AAC2 transcription an UAS (-393/-268) was identified that is essential for the expression of this gene. Two functional regulatory cis-elements are located within this UAS -binding sites for an ABFl factor and for HAP2/3/4/5 heteromeric complex. We examined relative contributions and mutual interactions of the ABFl and HAP2/3/4/5 factors in the activation of transcription from the UAS of the AAC2 gene. The whole UAS was dissected into smaller sub-fragments and tested for (i) the ability to form DNA-protein complexes with cellular proteins in vitro, (ii) the ability to confer heterologous expression using AAC3 gene lacking its own promoter, and (iii) the expression of AAC3-lacZ fusion instead of intact AAC3 gene. The obtained results demonstrated that: a) The whole UAS as well as sub-fragment containing only ABF1-binding site are able to form DNA-protein complexes with cellular proteins in oxygen- and heme- dependent manner. The experiments with antibody against the ABF1 showed that the ABF1 factor is one of the proteins binding to AAC2 promoter. We have been unsuccessful to prove the binding of cellular proteins to the HAP2/3/4/5-binding site. However, the presence of HAP2/3/4/5-binding site is necessary to drive a binding of cellular proteins to the ABF1-binding site in carbon source-dependent manner. b) The presence of both ABF1- and HAP2/3/4/5-binding sites and original spacing between them is necessary to confer the growth of Aaac2 mutant strain on non- fermentable carbon source when put in front of AAC3 gene introduced on centromeric vector to Aaac2 mutant strain. c) For the activation of AAC3-lacZ expression on both fermentable and non-fermentable carbon sources the only presence of two copies of HAP2/3/4/5-binding site is sufficient. However, activation of AAC3-lacZ expression by two copies of HAP2/3/4/5-binding site is very low. We can conclude that the presence of both ABF1- and HAP2/3/4/5-binding sites and original spacing between them is necessary to get strong activation of AAC2 gene. A gene homologous to Saccharomyces cerevisiae AAC genes coding for mitochondrial ADP/ATP carriers has been cloned from pathogenic yeast Candida parapsilosis. The cloned gene was sequenced and found to encode a polypeptide of 303 amino acids that shows homology with other yeast and mammal mitochondrial ADP/ATP carriers. The gene was designed CpAAC1 and was able to complement the growth phenotype of S. cerevisiae double deletion mutant (?aac2?aac3). The expression of the CpAAC1 gene was affected at normal aerobic conditions by the nature of carbon source used for growth. The concentration of oxygen had no effect to the expression of this gene. Hybridization experiments indicate that C. parapsilosis possesses a single gene encoding a mitochondrial ADP/ ATP carrier. (author)

  6. Proline biosynthesis in Saccharomyces cerevisiae: analysis of the PRO3 gene, which encodes delta 1-pyrroline-5-carboxylate reductase.

    OpenAIRE

    Brandriss, M C; Falvey, D A

    1992-01-01

    The PRO3 gene of Saccharomyces cerevisiae encodes the 286-amino-acid protein delta 1-pyrroline-5-carboxylate reductase [L-proline:NAD(P+) 5-oxidoreductase; EC 1.5.1.2], which catalyzes the final step in proline biosynthesis. The protein has substantial similarity to the pyrroline carboxylate reductases of diverse bacterial species, soybean, and humans. Using RNA hybridization and measurements of enzyme activity, we have determined that the expression of the PRO3 gene appears to be constitutiv...

  7. POS5 Gene of Saccharomyces cerevisiae Encodes a Mitochondrial NADH Kinase Required for Stability of Mitochondrial DNA

    OpenAIRE

    Strand, Micheline K.; Stuart, Gregory R.; Longley, Matthew J.; Graziewicz, Maria A; Dominick, Olivia C.; Copeland, William C.

    2003-01-01

    In a search for nuclear genes that affect mutagenesis of mitochondrial DNA in Saccharomyces cerevisiae, an ATP-NAD (NADH) kinase, encoded by POS5, that functions exclusively in mitochondria was identified. The POS5 gene product was overproduced in Escherichia coli and purified without a mitochondrial targeting sequence. A direct biochemical assay demonstrated that the POS5 gene product utilizes ATP to phosphorylate both NADH and NAD+, with a twofold preference for NADH. Disruption of POS5 inc...

  8. Mutational Analysis of the Gal4-Encoded Transcriptional Activator Protein of Saccharomyces Cerevisiae

    OpenAIRE

    Johnston, M.; Dover, J

    1988-01-01

    The GAL4 protein of Saccharomyces cerevisiae binds to DNA upstream of each of six genes and stimulates their transcription. To locate regions of the protein responsible for these processes, we identified and characterized 88 gal4 mutations selected in vivo to reduce the ability to GAL4 protein to activate transcription. These mutations alter two regions of GAL4 protein: the DNA binding domain, and the transcription activation domain. Some mutations in the DNA binding domain that abolish the a...

  9. GIT1, a gene encoding a novel transporter for glycerophosphoinositol in Saccharomyces cerevisiae.

    OpenAIRE

    Patton-Vogt, J L; Henry, S A

    1998-01-01

    Phosphatidylinositol catabolism in Saccharomyces cerevisiae cells cultured in media containing inositol results in the release of glycerophosphoinositol (GroPIns) into the medium. As the extracellular concentration of inositol decreases with growth, the released GroPIns is transported back into the cell. Exploiting the ability of the inositol auxotroph, ino1, to use exogenous GroPIns as an inositol source, we have isolated mutants (Git-) defective in the uptake and metabolism of GroPIns. One ...

  10. Saccharomyces cerevisiae aldolase mutants.

    OpenAIRE

    Lobo, Z

    1984-01-01

    Six mutants lacking the glycolytic enzyme fructose 1,6-bisphosphate aldolase have been isolated in the yeast Saccharomyces cerevisiae by inositol starvation. The mutants grown on gluconeogenic substrates, such as glycerol or alcohol, and show growth inhibition by glucose and related sugars. The mutations are recessive, segregate as one gene in crosses, and fall in a single complementation group. All of the mutants synthesize an antigen cross-reacting to the antibody raised against yeast aldol...

  11. New Insights into Trehalose Metabolism by Saccharomyces cerevisiae: NTH2 Encodes a Functional Cytosolic Trehalase, and Deletion of TPS1 Reveals Ath1p-Dependent Trehalose Mobilization? †

    OpenAIRE

    Jules, Matthieu; Beltran, Gemma; François, Jean; Parrou, Jean Luc

    2007-01-01

    In the yeast Saccharomyces cerevisiae, the synthesis of endogenous trehalose is catalyzed by a trehalose synthase complex, TPS, and its hydrolysis relies on a cytosolic/neutral trehalase encoded by NTH1. In this work, we showed that NTH2, a paralog of NTH1, encodes a functional trehalase that is implicated in trehalose mobilization. Yeast is also endowed with an acid trehalase encoded by ATH1 and an H+/trehalose transporter encoded by AGT1, which can together sustain assimilation of exogenous...

  12. 21 CFR 866.5785 - Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems.

    Science.gov (United States)

    2010-04-01

    ...Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems. 866.5785...Anti-Saccharomyces cerevisiae (S. cerevisiae ) antibody (ASCA) test systems. (a) Identification...Anti-Saccharomyces cerevisiae (S. cerevisiae ) antibody (ASCA) test system is an in...

  13. Identification and isolation of the gene encoding the small subunit of ribonucleotide reductase from Saccharomyces cerevisiae: DNA damage-inducible gene required for mitotic viability.

    OpenAIRE

    Elledge, S.J.; Davis, R.W.

    1987-01-01

    Ribonucleotide reductase catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. The gene encoding the small subunit of ribonucleotide reductase was isolated from a Saccharomyces cerevisiae genomic DNA expression library in lambda gt11 by a fortuitous cross-reaction with anti-RecA antibodies. The cross-reaction was due to an identity between the last four amino acids of each protein. The gene has been named RNR2 and is centromere linked on ...

  14. PET genes of Saccharomyces cerevisiae.

    OpenAIRE

    Tzagoloff, A; Dieckmann, C L

    1990-01-01

    We describe a collection of nuclear respiratory-defective mutants (pet mutants) of Saccharomyces cerevisiae consisting of 215 complementation groups. This set of mutants probably represents a substantial fraction of the total genetic information of the nucleus required for the maintenance of functional mitochondria in S. cerevisiae. The biochemical lesions of mutants in approximately 50 complementation groups have been related to single enzymes or biosynthetic pathways, and the corresponding ...

  15. RRN3 gene of Saccharomyces cerevisiae encodes an essential RNA polymerase I transcription factor which interacts with the polymerase independently of DNA template.

    OpenAIRE

    Yamamoto, R T; Nogi, Y.; Dodd, J A; M. Nomura

    1996-01-01

    RRN3 is one of the RRN genes specifically required for the transcription of rDNA by RNA polymerase I (Pol I) in Saccharomyces cerevisiae. We have cloned the gene, determined the nucleotide sequence, and found that it is an essential gene which encodes a protein of calculated molecular weight of 72 369. Extracts prepared from rrn3 mutants were defective in in vitro transcription of rDNA templates. We used extracts from a strain containing an epitope-tagged Rrn3 protein to purify a factor that ...

  16. An essential Saccharomyces cerevisiae gene homologous to SNF2 encodes a helicase-related protein in a new family.

    OpenAIRE

    Laurent, B C; Yang, X; Carlson, M.

    1992-01-01

    The Saccharomyces cerevisiae SNF2 gene affects the expression of many diversely regulated genes and has been implicated in transcriptional activation. We report here the cloning and characterization of STH1, a gene that is homologous to SNF2. STH1 is essential for mitotic growth and is functionally distinct from SNF2. A bifunctional STH1-beta-galactosidase protein is located in the nucleus. The predicted 155,914-Da STH1 protein is 72% identical to SNF2 over 661 amino acids and 46% identical o...

  17. Saccharomyces cerevisiae YOR071C encodes the high affinity nicotinamide riboside transporter Nrt1.

    Science.gov (United States)

    Belenky, Peter A; Moga, Tiberiu G; Brenner, Charles

    2008-03-28

    NAD(+) is an essential coenzyme for hydride transfer enzymes and a substrate of sirtuins and other NAD(+)-consuming enzymes. Nicotinamide riboside is a recently discovered eukaryotic NAD(+) precursor converted to NAD(+) via the nicotinamide riboside kinase pathway and by nucleosidase activity and nicotinamide salvage. Nicotinamide riboside supplementation of yeast extends replicative life span on high glucose medium. The molecular basis for nicotinamide riboside uptake was unknown in any eukaryote. Here, we show that deletion of a single gene, YOR071C, abrogates nicotinamide riboside uptake without altering nicotinic acid or nicotinamide import. The gene, which is negatively regulated by Sum1, Hst1, and Rfm1, fully restores nicotinamide riboside import and utilization when resupplied to mutant yeast cells. The encoded polypeptide, Nrt1, is a predicted deca-spanning membrane protein related to the thiamine transporter, which functions as a pH-dependent facilitator with a K(m) for nicotinamide riboside of 22 microm. Nrt1-related molecules are conserved in particular fungi, suggesting a similar basis for nicotinamide riboside uptake. PMID:18258590

  18. Fungal genomics beyond Saccharomyces cerevisiae?

    DEFF Research Database (Denmark)

    Hofmann, Gerald; Mcintyre, Mhairi; Nielsen, Jens

    2003-01-01

    Fungi are used extensively in both fundamental research and industrial applications. Saccharomyces cerevisiae has been the model organism for fungal research for many years, particularly in functional genomics. However, considering the diversity within the fungal kingdom, it is obvious that the application of the existing methods of genome, transcriptome, proteome and metabolome analysis to other fungi has enormous potential, especially for the production of food and food ingredients. The develo...

  19. Glucose repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kayikci, Omur; Nielsen, Jens

    2015-01-01

    Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective...

  20. Filamentous growth in Saccharomyces cerevisiae / Filamentação em Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Sandra Regina, Ceccato-Antonini; Peter Edwin, Sudbery.

    2004-09-01

    Full Text Available O dimorfismo em fungos é um fenômeno complexo acionado por um grande número de fatores ambientais e consiste num padrão alternante e reversível de crescimento, oscilando entre formas elípticas e filamentosas de células. É de grande importância o entendimento dos mecanismos que regulam esses eventos [...] devido as suas implicações na patogenicidade, diferenciação celular e indústria. Células diplóides de Saccharomyces cerevisiae mudam de células brotantes para pseudohifas quando em condições limitantes de nitrogênio, o que confere às células uma vantagem na procura por alimento. A deficiência de nitrogênio é 'percebida' por pelo menos dois caminhos sinalizadores: 'MAP kinase' (MAPK) e 'PKA' (cAMP-dependent protein kinase A). O resultado dessa sinalização é a expressão de genes específicos para filamentação, cujos perfis de expressão mudam e são acompanhados por um retardo da fase G2 do ciclo celular e um período prolongado de crescimento polarizado. Células haplóides mostram um tipo de crescimento similar após prolongada incubação em meio rico. As células formam cadeias e invadem o ágar na borda da colônia, mas não se tornam alongadas. Esse tipo de crescimento é conhecido como crescimento invasivo haplóide. Os álcoois podem também induzir crescimento filamentoso em S. cerevisiae, ocasionando uma morfologia alongada e aberrante. Nesse artigo revisamos as três formas de crescimento filamentoso incluindo os caminhos envolvidos na percepção, sinalização e transdução do sinal durante o crescimento filamentoso. Abstract in english Fungal dimorphism is a complex phenomenon triggered by a large variety of environmental factors and consists of a reversible alternating pattern of growth between different elliptical and filamentous forms of cells. Understanding the mechanisms that regulate these events is of major interest because [...] of their implications in fungal pathogenesis, cell differentiation and industry. Diploid cells of Saccharomyces cerevisiae transform from budding yeast to pseudohyphae when starved for nitrogen, giving the cells an advantage in food foraging, which is sensed by at least two signal transduction pathways: the MAP kinase (MAPK) and the PKA (cAMP-dependent protein kinase A) pathways. The output of these signalling pathways is the expression of pseudohypha-specific genes, whose expression profiles change and is accompanied by a G2 delay in the cell cycle and a prolonged period of polarized growth. Haploid yeast strains show a similar growth type after prolonged incubation on rich medium plates. The cells form chains and invade the agar on the edge of the colony, but they do not become elongated. This growth type is referred to as haploid invasive growth. Alcohols can also induce filamentous growth in S. cerevisiae, promoting aberrant and elongated morphology. The three forms of filamentous growth are revised in this article and also the pathways involved in sensing, signaling and signal transduction during filamentous growth.

  1. Sequencing and heterologous expression in Saccharomyces cerevisiae of a Cryptococcus neoformans cDNA encoding a plasma membrane H(+)-ATPase.

    Science.gov (United States)

    Gorgojo, B; Portillo, F; Martínez-Suárez, J V

    2000-12-20

    A cDNA containing an open reading frame encoding a putative plasma membrane H(+)-ATPase in the human pathogenic basidiomycetous yeast Cryptococcus neoformans was cloned and sequenced by means of PCR and cDNA library hybridization. The cloned cDNA is 3475 bp in length, containing a 2994 bp open reading frame encoding a polypeptide of 997 amino acids. As in the case of another basidiomycetous fungus (Uromyces fabae), the deduced amino acid sequence of CnPMA1 was found to be more homologous to those of P-type H(+)-ATPases from higher plants than to those from ascomycetous fungi. In order to prove the sequenced cDNA corresponds to a H(+)-ATPase, it was expressed in Saccharomyces cerevisiae and found to functionally replace its own H(+)-ATPase. Kinetic studies of CnPMA1 compared to ScPMA1 show differences in V(max) values and H(+)-pumping in reconstituted vesicles. The pH optimum and K(m) values are similar in both enzymes. PMID:11118522

  2. Glycolipids of Saccharomyces cerevisiae Cell

    Directory of Open Access Journals (Sweden)

    Renuka Malhotra

    2005-01-01

    Full Text Available Total lipids of Saccharomyces cerevisiae were isolated by chloroform and methanol (2:1. Glycolipids were separated from total lipids by silicic acid chromatography. Glycolipid’s constituent sugars and fatty acids were analyzed by using Gas Liquid Chromatography. Galactose was the prominent sugar followed by mannose. Relative concentrations of fucose, mannose, galactose and glucose in the glycolipid were 5.3, 35.2, 55.1 and 4.2%. 16:0, 18:0, 18:1, 18:2 and 18:3 were the major fatty acids of the total glycolipids. Oleic acid was the dominating fatty acid followed by linoliec acid. They were separated into different fractions by using DEAE-Sephadex ion exchange chromatography. Glycolipids were fractionated and identified as cerebrosides, ceramide polyhexosides, sulfatides, monoglucosyldiglycerides and diglucosyldiglycerides. Ceramide polyhexosides were present in higher concentration as compared to other fractions.

  3. Glucose repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kayikci, Omur; Nielsen, Jens

    2015-01-01

    Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective at post-transcriptional and post-translational levels. This review describes effects of glucose repression on yeast carbon metabolism with a focus on roles of the Snf3/Rgt2 glucose-sensing pathway and Snf1 signal transduction in establishment and relief of glucose repression.

  4. Endogenous Xylose Pathway in Saccharomyces cerevisiae

    OpenAIRE

    Toivari, Mervi H.; Salusjärvi, Laura; Ruohonen, Laura; Penttilä, Merja

    2004-01-01

    The baker's yeast Saccharomyces cerevisiae is generally classified as a non-xylose-utilizing organism. We found that S. cerevisiae can grow on d-xylose when only the endogenous genes GRE3 (YHR104w), coding for a nonspecific aldose reductase, and XYL2 (YLR070c, ScXYL2), coding for a xylitol dehydrogenase (XDH), are overexpressed under endogenous promoters. In nontransformed S. cerevisiae strains, XDH activity was significantly higher in the presence of xylose, but xylose reductase (XR) activit...

  5. Genetic analysis of the Saccharomyces cerevisiae RHO3 gene, encoding a rho-type small GTPase, provides evidence for a role in bud formation

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Jun; Toh-e, Akio; Matsui, Yashushi [Univ. of Tokyo (Japan)

    1996-02-01

    RHO3 encodes a Rho-type small GTPase of the yeast Saccharomyces cerevisiae. We isolated temperature-sensitive alleles and a dominant active allele of RHO3. Ts{sup -} rho3 cells lost cell polarity during bud formation and grew more isotropically than wild-type cells at nonpermissive temperatures. In contrast, cells carrying a dominant active mutant RHO3 displayed cold sensitivity, and the cells became elongated and bent, often at the position where actin patches were concentrated. These phenotypes of the rho3 mutants strongly suggest that RHO3 is involved in directing the growing points during bud formation. In addition, we found that SRO6, previously isolated as a multicopy suppressor of rho3, is the same as SEC4. The sec4-2 mutation was synthetic lethal with temperature-sensitive rho3 mutations and suppressed the cold sensitivity caused by a dominant active mutant RHO3. The genetic interactions between RHO3 and SEC4, taken together with the fact that the Rab-type GTPase Sec4p is required to fuse secretory vesicles together with plasma membrane for exocytosis, support a model in which the Rho3p pathway modulates morphogenesis during bud growth via directing organization of the actin cytoskeleton and the position of the secretory machinery for exocytosis. 59 refs., 8 figs., 1 tab.

  6. Metabolic Engineering of Glycerol Production in Saccharomyces cerevisiae:

    OpenAIRE

    Overkamp, K.M.; Bakker, B.M.; Kotter, P.; Luttik, M.A.H.; van Dijken, J P; Pronk, J T

    2002-01-01

    Inactivation of TPI1, the Saccharomyces cerevisiae structural gene encoding triose phosphate isomerase, completely eliminates growth on glucose as the sole carbon source. In tpi1-null mutants, intracellular accumulation of dihydroxyacetone phosphate might be prevented if the cytosolic NADH generated in glycolysis by glyceraldehyde-3-phosphate dehydrogenase were quantitatively used to reduce dihydroxyacetone phosphate to glycerol. We hypothesize that the growth defect of tpi1-null mutants is c...

  7. Transcriptional regulation of the DAL5 gene in Saccharomyces cerevisiae.

    OpenAIRE

    Rai, R; Genbauffe, F; Lea, H Z; Cooper, T G

    1987-01-01

    We demonstrate that the DAL5 gene, encoding a necessary component of the allantoate transport system, is constitutively expressed in Saccharomyces cerevisiae. Its relatively high basal level of expression did not increase further upon addition of allantoin pathway intermediates. However, steady-state DAL5 mRNA levels dropped precipitously when a repressive nitrogen source was provided. These control characteristics of DAL5 expression make this gene a good model with which to unravel the mecha...

  8. Positive and negative transcriptional control by heme of genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase in Saccharomyces cerevisiae.

    OpenAIRE

    Thorsness, M; Schafer, W.; D'Ari, L; RINE, J.

    1989-01-01

    Responses of the yeast genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase, HMG1 and HMG2, to in vivo changes in heme concentrations were investigated. Expression of the genes was determined by direct measurement of the mRNA transcribed from each gene, by direct assay of the enzyme activity encoded by each gene, and by measurement of the expression of lacZ fusions to the control regions of each gene. These studies indicated that expression of HMG1 was stimulated by heme, whereas ex...

  9. Ferrofluid modified Saccharomyces cerevisiae cells for biocatalysis.

    Czech Academy of Sciences Publication Activity Database

    Šafa?íková, Miroslava; Mad?rová, Zde?ka; Šafa?ík, Ivo

    2009-01-01

    Ro?. 42, - (2009), s. 521-524. ISSN 0963-9969 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk(CZ) OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : Saccharomyces cerevisiae * magnetic fluid * hydrogen peroxide Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.414, year: 2009

  10. Suppressor analysis of temperature-sensitive mutations of the largest subunit of RNA polymerase I in Saccharomyces cerevisiae: a suppressor gene encodes the second-largest subunit of RNA polymerase I.

    OpenAIRE

    Yano, R; Nomura, M

    1991-01-01

    The SRP3-1 mutation is an allele-specific suppressor of temperature-sensitive mutations in the largest subunit (A190) of RNA polymerase I from Saccharomyces cerevisiae. Two mutations known to be suppressed by SRP3-1 are in the putative zinc-binding domain of A190. We have cloned the SRP3 gene by using its suppressor activity and determined its complete nucleotide sequence. We conclude from the following evidence that the SRP3 gene encodes the second-largest subunit (A135) of RNA polymerase I....

  11. Nitrogen Catabolite Repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider

    1999-01-01

    In Saccharomyces cerevisiae the expression of all known nitrogen catabolite pathways are regulated by four regulators known as Gln3, Gat1, Da180, and Deh1. This is known as nitrogen catabolite repression (NCR). They bind to motifs in the promoter region to the consensus sequence S' GATAA 3'. Gln3 and Gat1 act positively on gene expression whereas :Da180 and Deh1 act negatively. Expression of nitrogen catabolite pathway genes known to be regulated by these four regulators are glutamine, glutamate, proline, urea, arginine, GABA, and allantoine. In addition, the expression of the genes encoding the general amino acid permease and the ammonium permease are also regulated by these four regulatory proteins. Another group of genes whose expression is also regulated by Gln3, Gat1, Da180, and Deh1 are some proteases, CPS1, PRB1, LAP1, and PEP4, responsible for the degradation of proteins into amino acids thereby providing a nitrogen source to the cell.In this review, all known promoter sequences related to expression of nitrogen catabolite pathways are discussed as well as other regulatory proteins. Overview of metabolic pathways and promoters are presented.

  12. Genetic characterization of genes encoding enzymes catalyzing addition of phospho-ethanolamine to the glycosylphosphatidylinositol anchor in Saccharomyces cerevisiae.

    Science.gov (United States)

    Toh-e, Akio; Oguchi, Tomoko

    2002-10-01

    MPC1/GPI13/YLL031C, one of the genes involved in the addition of phospho-ethanolamine to the glycosylphosphatidylinositol (GPI) anchor core, is an essential gene. Three available temperature-sensitive mutant alleles, mpc1-3, mpc1-4, and mpc1-5, displayed different phenotypes to each other and, correspondingly, these mutants were found to have different mutations in the MPC1 ORF. Temperature-sensitivity of mpc1-5 mutants was suppressed by 5 mM ZnSO(4) and by 5 mM MnCl(2). Multicopy suppressors were isolated from mpc1-5 mutant. Suppressors commonly effective to mpc1-4 and mpc1-5 mutations are PSD1, encoding phosphatidylserine decarboxylase, and ECM33, which were found to suppress the temperature-sensitive phenotype shown by the fsr2-1 and las21delta mutants, those of which have defects in the GPI anchor synthesis. PSD2, encoding another phosphatidylserine decarboxylase that is localized in Golgi/vacuole, was found to be able to serve as a multicopy suppressor of mpc1 and fsr2-1 mutants but not of the las21 delta mutant. In contrast to psd1delta, psd2delta showed a synthetic growth defect with mpc1 mutants but not with fsr2-1 or las21delta. Furthermore, psd1delta psd2delta mpc1 triple mutants did not form colonies on nutrient medium unless ethanolamine was supplied to the medium, whereas psd1delta psd2 delta fsr2-1 or psd1delta psd2 delta las21delta triple mutants grew on nutrient medium without supplementation of ethanolamine. These observations suggest that Mpc1 preferentially utilizes phosphatidylethanolamine produced by Psd2 that is localized in Golgi/vacuole. fsr2-1 dpl1 Delta psd1delta strains showed slower growth than fsr2-1 dpl1delta psd2 delta, suggesting that Fsr2 enzyme depends more on Dpl1 and Psd1 for production of phosphatidylethanolamine. Las21 did not show preference for the metabolic pathway to produce phosphatidylethanolamine. PMID:12441642

  13. Acid excreting mutants of yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae mutants acidifying glucose medium containing bromocresol purple were shown to excrete protons when placed in unbuffered water in the absence of any external carbon source. The mutants belong to 16 different complementation groups. Most of them do not grow on glycerol and the excreted protons are associated to particular sets of organic anions such as citrate, aconitate, succinate, fumarate or malate. These novel types of respiratory mutations seem to be located in genes operating in the Krebs or glyoxylate cycle

  14. PRODUCTION OF ERGOSTEROL BY SACCHAROMYCES CEREVISIAE

    OpenAIRE

    Blažena Lavová; Andrea Hároniková; Ivana Márová; Dana Urminská

    2013-01-01

    Ergosterol is an essential component of yeast cells that maintains the integrity of the membrane. In this study the production of ergosterol by yeast Saccharomyces cerevisiae strains Kolín, Gyöng and 612 was investigated. Ergosterol was isolated by multilevel extraction associated with saponification and analyzed by reverse phase high performance liquid chromatography with PDA detector. It was found that the highest content of ergosterol (7055.53 ?g.g-1 d.w.) was reached after 52 hours of str...

  15. Transformation of Saccharomyces cerevisiae by electroporation.

    OpenAIRE

    Delorme, E

    1989-01-01

    A method for introducing heterologous DNA into Saccharomyces cerevisiae rapidly and efficiently by electroporation was developed. Transformant colonies appeared somewhat sooner than by the LiCl or spheroplast transformation method, and the time spent in manipulation was much less than for these two methods. The pores in the cell membrane formed by the high voltage of electroporation were resealed within 6 to 7 min after electroporation. At a capacitance of 25 microF, the optimum voltage was 2...

  16. Cell Wall Assembly in Saccharomyces cerevisiae

    OpenAIRE

    Lesage, Guillaume; Bussey, Howard

    2006-01-01

    An extracellular matrix composed of a layered meshwork of ?-glucans, chitin, and mannoproteins encapsulates cells of the yeast Saccharomyces cerevisiae. This organelle determines cellular morphology and plays a critical role in maintaining cell integrity during cell growth and division, under stress conditions, upon cell fusion in mating, and in the durable ascospore cell wall. Here we assess recent progress in understanding the molecular biology and biochemistry of cell wall synthesis and it...

  17. Heterologous Expression of Genes in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    ÖZCAN, Numan

    2001-01-01

    Both an a-amylase gene of Bacillus subtilis RSKK246 and a gene encoding b-glucanase from B.subtilis RSKK243 were cloned and expressed in both E.coli XL1-Blue MRF and B.subtilis YB886 by using the vectors pUC18 and pUB110 respectively. These genes were also cloned into the E.coli-yeast shuttle vectors pRS406 and pRS416 for transfer into the yeast Saccharomyces cerevisiae.These constructs carrying a -amylase and a -glucanase,genes which were cloned into the pRS406 vector,were expressed by i...

  18. Myo-inositol transport in Saccharomyces cerevisiae.

    OpenAIRE

    Nikawa, J; Nagumo, T; Yamashita, S

    1982-01-01

    myo-Inositol uptake in Saccharomyces cerevisiae was dependent on temperature, time, and substrate concentration. The transport obeyed saturation kinetics with an apparent Km for myo-inositol of 0.1 mM, myo-Inositol analogs, such as scyllo-inositol, 2-inosose, mannitol, and 1,2-cyclohexanediol, had no effect on myo-inositol uptake, myo-Inositol uptake required metabolic energy. Removal of D-glucose resulted in a loss of activity, and azide and cyanide ions were inhibitory. In the presence of D...

  19. Biosorption of heavy metals by Saccharomyces cerevisiae.

    Science.gov (United States)

    Volesky, B; May-Phillips, H A

    1995-01-01

    Abundant and common yeast biomass has been examined for its capacity to sequester heavy metals from dilute aqueous solutions. Live and non-living biomass of Saccharomyces cerevisiae differs in the uptake of uranium, zinc and copper at the optimum pH 4-5. Culture growth conditions can influence the biosorbent metal uptake capacity which normally was: living and non-living brewer's yeast: U > Zn > Cd > Cu; non-living baker's yeast: Zn > (Cd) > U > Cu; living baker's yeast: Zn > Cu approximately (Cd) > U. Non-living brewer's yeast biomass accumulated 0.58 mmol U/g. The best biosorbent of zinc was non-living baker's yeast (approximately 0.56 mmol Zn/g). Dead cells of S. cerevisiae removed approximately 40% more uranium or zinc than the corresponding live cultures. Biosorption of uranium by S. cerevisiae was a rapid process reaching 60% of the final uptake value within the first 15 min of contact. Its deposition differing from that of other heavy metals more associated with the cell wall, uranium was deposited as fine needle-like crystals both on the inside and outside of the S. cerevisiae cells. PMID:7765919

  20. Prezygotic reproductive isolation between Saccharomyces cerevisiae and Saccharomyces paradoxus

    Directory of Open Access Journals (Sweden)

    Greig Duncan

    2008-01-01

    Full Text Available Abstract Background Matings between different Saccharomyces sensu stricto yeast species produce sexually sterile hybrids, so individuals should avoid mating with other species. Any mechanism that reduces the frequency of interspecific matings will confer a selective advantage. Here we test the ability of two closely-related Saccharomyces sensu stricto species to select their own species as mates and avoid hybridisation. Results We set up mate choice tests, using five independently isolated pairs of species, in which individual germinating spores were presented with the opportunity to mate either with a germinating spore of their own species or with a germinating spore of the other species. For all five strain pairs, whether a S. cerevisiae or S. paradoxus occupies the role of "chooser" strain, the level of hybridisation that is observed between the two species is significantly lower than would be expected if mates were selected at random. We also show that, overall, S. cerevisiae exhibited a stronger own-species preference than S. paradoxus. Conclusion Prezygotic reproductive isolation is well known in higher organisms but has been largely overlooked in yeast, an important model microbe. Here we present the first report of prezygotic reproductive isolation in Saccharomyces. Prezygotic reproductive isolation may be important in yeast speciation or yeast species cohesion, and may have evolved to prevent wasted matings between different species. Whilst yeast has long been used as a genetic model system, little is known about yeast in the wild. Our work sheds light on an interesting aspect of yeast natural behaviour: their ability to avoid costly interspecific matings.

  1. Isolation of a Candida albicans DNA sequence conferring adhesion and aggregation on Saccharomyces cerevisiae.

    OpenAIRE

    Barki, M; Koltin, Y.; Yanko, M; Tamarkin, A.; Rosenberg, M.

    1993-01-01

    Candida albicans is an opportunistic pathogen which may give rise to superficial and systemic infections. In the present study, C. albicans adhesion was studied by expression of C. albicans DNA sequences encoding adhesion functions in a nonadherent strain of Saccharomyces cerevisiae. Adherent transformant cells of S. cerevisiae harbouring a C. albicans genomic library cloned in a yeast-Escherichia coli shuttle vector were selected by using tissue culture-treated polystyrene as the attachment ...

  2. Enhancing sesquiterpene production in Saccharomyces cerevisiae through in silico driven metabolic engineering

    DEFF Research Database (Denmark)

    Asadollahi, Mohammadali; Maury, Jerome; Patil, Kiran Raosaheb; schalk, Michel; Clark, Anthony; Nielsen, Jens

    2009-01-01

    A genome-scale metabolic model was used to identify new target genes for enhanced biosynthesis of sesquiterpenes in the yeast Saccharomyces cerevisiae. The effect of gene deletions on the flux distributions in the metabolic model of S. cerevisiae was assessed using OptGene as the modeling framework and minimization of metabolic adjustments (MOMA) as objective function. Deletion of NADPH-dependent glutamate dehydrogenase encoded by GDH1 was identified as the best target gene for the improvement o...

  3. Spk1, a new kinase from Saccharomyces cerevisiae, phosphorylates proteins on serine, threonine, and tyrosine.

    OpenAIRE

    Stern, D. F.; Zheng, P.; Beidler, D R; Zerillo, C

    1991-01-01

    A Saccharomyces cerevisiae lambda gt11 library was screened with antiphosphotyrosine antibodies in an attempt to identify a gene encoding a tyrosine kinase. A subclone derived from one positive phage was sequenced and found to contain an 821-amino-acid open reading frame that encodes a protein with homology to protein kinases. We tested the activity of the putative kinase by constructing a vector encoding a glutathione-S-transferase fusion protein containing most of the predicted polypeptide....

  4. Electrical stimulation of saccharomyces cerevisiae cultures Estimulação elétrica de células de Saccharomyces cerevisiae

    OpenAIRE

    Ofelia Q.F. Araújo; Maria Alice Z Coelho; Isabel C.P. Margarit; Carlos A. Vaz-Junior; Maria Helena M. Rocha-Leão

    2004-01-01

    Modulation of cell endogenous membrane potential by an external electrical field influences the structure and function of membrane compartments, proteins and lipid bi-layer. In this work, the effects of applied potential on Saccharomyces cerevisiae growth were characterized through simple yet conclusive experiments. Cell growth time profile and cell division were investigated as macroscopic response to the electrical stimulation. Control experiments were conducted under identical conditions e...

  5. Synchronization of the Budding Yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Foltman, Magdalena; Molist, Iago; Sanchez-Diaz, Alberto

    2016-01-01

    A number of model organisms have provided the basis for our understanding of the eukaryotic cell cycle. These model organisms are generally much easier to manipulate than mammalian cells and as such provide amenable tools for extensive genetic and biochemical analysis. One of the most common model organisms used to study the cell cycle is the budding yeast Saccharomyces cerevisiae. This model provides the ability to synchronise cells efficiently at different stages of the cell cycle, which in turn opens up the possibility for extensive and detailed study of mechanisms regulating the eukaryotic cell cycle. Here, we describe methods in which budding yeast cells are arrested at a particular phase of the cell cycle and then released from the block, permitting the study of molecular mechanisms that drive the progression through the cell cycle. PMID:26519319

  6. Expression of the E.coli pntA and pntB genes encoding nicotinamide nucleotide transhydrogenase in Saccharomyces cerevisiae and its effect on product formation during anaerobic glucose fermentation

    DEFF Research Database (Denmark)

    Anderlund, M.; Nissen, Torben Lauesgaard; Nielsen, Jens Bredal; Villadsen, John; Rydström, J.; Hahn-Hägerdal, B.; Kielland-Brandt, M.C.

    1999-01-01

    We studied the physiological effect of the interconversion between the NAD(H) and NADP(H) coenzyme systems in recombinant Saccharomyces cerevisiae expressing the membrane-bound transhydrogenase from Escherichia coli. Our objective was to determine if the membrane-bound transhydrogenase could work in reoxidation of NADH to NAD(+) in S. cerevisiae and thereby reduce glycerol formation during anaerobic fermentation. Membranes isolated from the recombinant strains exhibited reduction of 3-acetylpyri...

  7. Phenotypical signs and chemical composition of Saccharomyces cerevisiae – mannoprotein producers

    Directory of Open Access Journals (Sweden)

    Agafia USATII

    2012-11-01

    Full Text Available Phenotypical signs and chemical composition of Saccharomyces cerevisiae CNMN-Y-18 and Saccharomyces cerevisiae CNMN-Y-19 yeast strains are described in this article. The presence of protein complexes with high content of irreplaceable amino acids and antioxidant enzymes, as well as polysaccharides with predominance of mannoproteins allow to recommend these yeast strains for the utilization in biotechnology. Results are of interest for the standard description of yeast strains offered as object for industrial appointment.

  8. Phenotypical signs and chemical composition of Saccharomyces cerevisiae – mannoprotein producers

    OpenAIRE

    Agafia USATII; Elena MOLODOI; Nadejda EFREMOVA; Natalia CHISELITA; Tamara BORISOVA; Ludmila FULGA

    2012-01-01

    Phenotypical signs and chemical composition of Saccharomyces cerevisiae CNMN-Y-18 and Saccharomyces cerevisiae CNMN-Y-19 yeast strains are described in this article. The presence of protein complexes with high content of irreplaceable amino acids and antioxidant enzymes, as well as polysaccharides with predominance of mannoproteins allow to recommend these yeast strains for the utilization in biotechnology. Results are of interest for the standard description of yeast strains offered as objec...

  9. Study on biosorption of uranium by alginate immobilized saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae has great capability of biosorption of uranium. The maxium uptake is 172.4 mg/g according to this study. To adapt to the application of the biomass in the field, the biosorption of uranium by cross-linked and alginate calcium immobilized Saccharomyces cerevisiae is studied. Results indicate the maxium uptake is 185.2 mg/g by formaldehyde cross-linked biomass, and it is 769.2 mg/g by alginate calcium immobilized biomass. (authors)

  10. Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model

    Directory of Open Access Journals (Sweden)

    Serge Feyder

    2015-01-01

    Full Text Available The yeast Saccharomyces cerevisiae is one of the best characterized eukaryotic models. The secretory pathway was the first trafficking pathway clearly understood mainly thanks to the work done in the laboratory of Randy Schekman in the 1980s. They have isolated yeast sec mutants unable to secrete an extracellular enzyme and these SEC genes were identified as encoding key effectors of the secretory machinery. For this work, the 2013 Nobel Prize in Physiology and Medicine has been awarded to Randy Schekman; the prize is shared with James Rothman and Thomas Südhof. Here, we present the different trafficking pathways of yeast S. cerevisiae. At the Golgi apparatus newly synthesized proteins are sorted between those transported to the plasma membrane (PM, or the external medium, via the exocytosis or secretory pathway (SEC, and those targeted to the vacuole either through endosomes (vacuolar protein sorting or VPS pathway or directly (alkaline phosphatase or ALP pathway. Plasma membrane proteins can be internalized by endocytosis (END and transported to endosomes where they are sorted between those targeted for vacuolar degradation and those redirected to the Golgi (recycling or RCY pathway. Studies in yeast S. cerevisiae allowed the identification of most of the known effectors, protein complexes, and trafficking pathways in eukaryotic cells, and most of them are conserved among eukaryotes.

  11. Response of Saccharomyces cerevisiae to cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia], e-mail: luamatu@uol.com.br; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Rosa, Carlos Augusto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: carlrosa@icb.ufmg

    2009-07-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K{sup +} and Na{sup +}) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  12. Expression of the rgMT gene, encoding for a rice metallothionein-like protein in Saccharomyces cerevisiae and Arabidopsis thaliana

    Indian Academy of Sciences (India)

    Shumei Jin; Dan Sun; Ji Wang; Ying Li; Xinwang Wang; Shenkui Liu

    2014-12-01

    Metallothioneins (MTs) are cysteine-rich proteins of low molecular weight with many attributed functions, such as providing protection against metal toxicity, being involved in regulation of metal ions uptake that can impact plant physiology and providing protection against oxidative stress. However, the precise function of the metallothionein-like proteins such as the one coded for rgMT gene isolated from rice (Oryza sativa L.) is not completely understood. The whole genome analysis of rice (O. sativa) showed that the rgMT gene is homologue to the Os11g47809 on chromosome 11 of O. sativa sp. japonica genome. This study used the rgMT coding sequence to create transgenic lines to investigate the subcellular localization of the protein, as well as the impact of gene expression in yeast (Saccharomyces cerevisiae) and Arabidopsis thaliana under heavy metal ion, salt and oxidative stresses. The results indicate that the rgMT gene was expressed in the cytoplasm of transgenic cells. Yeast cells transgenic for rgMT showed vigorous growth compared to the nontransgenic controls when exposed to 7mM CuCl2, 10 mM FeCl2, 1 M NaCl, 24 mM NaHCO3 and 3.2 mM H2O2, but there was no significant difference for other stresses tested. Similarly, Arabidopsis transgenic for rgMT displayed significantly improved seed germination rates over that of the control when the seeds were stressed with 100 M CuCl2 or 1 mM H2O2. Increased biomass was observed in the presence of 100 M CuCl2, 220 M FeCl2, 3 mM Na2CO3, 5 mM NaHCO3 or 1 mM H2O2. These results indicate that the expression of the rice rgMT gene in transgenic yeast and Arabidopsis is implicated in improving their tolerance for certain salt and peroxide stressors.

  13. Specific distribution of the Saccharomyces cerevisiae linker histone homolog HHO1p in the chromatin

    OpenAIRE

    Freidkin, Ilya; Katcoff, Don J.

    2001-01-01

    In virtually all eukaryotic organisms, linker DNA between nucleosomes is associated with a histone termed linker histone or histone H1. In Saccharomyces cerevisiae, HHO1 encodes a putative linker histone with very significant homology to histone H1. The encoded protein is expressed in the nucleus, but has not been shown to affect global chromatin structure, nor has its deletion shown any detectable phenotype. In vitro chromatin assembly experiments with recombinant HHO1p have shown that it is...

  14. Redox balancing in recombinant strains of Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Anderlund, M.

    1998-09-01

    In metabolically engineered Saccharomyces cerevisiae expressing Pichia stipitis XYL1 and XYL2 genes, encoding xylose reductase (XR) and xylitol dehydrogenase (XDH), respectively, xylitol is excreted as the major product during anaerobic xylose fermentation and only low yields of ethanol are produced. This has been interpreted as a result of the dual cofactor dependence of XR and the exclusive use of NAD{sup +} by XDH. The excretion of xylitol was completely stopped and the formation of glycerol and acetic acid were reduced in xylose utilising S. cerevisiae strains cultivated in oxygen-limited conditions by expressing lower levels of XR than of XDH. The expression level of XYL1 and XYL2 were controlled by changing the promoters and transcription directions of the genes. A new functional metabolic pathway was established when Thermus thermophilus xylA gene was expressed in S. cerevisiae. The recombinant strain was able to ferment xylose to ethanol when cultivated on a minimal medium containing xylose as only carbon source. In order to create a channeled metabolic transfer in the two first steps of the xylose metabolism, XYL1 and XYL2 were fused in-frame and expressed in S. cerevisiae. When the fusion protein, containing a linker of three amino acids, was co expressed together with native XR and XDH monomers, enzyme complexes consisting of chimeric and native subunits were formed. The total activity of these complexes exhibited 10 and 9 times higher XR and XDH activity, respectively, than the original conjugates, consisting of only chimeric subunits. This strain produced less xylitol and the xylitol yield was lower than with strains only expressing native XR and XDH monomers. In addition, more ethanol and less acetic acid were formed. A new gene encoding the cytoplasmic transhydrogenase from Azotobacter vinelandii was cloned. The enzyme showed high similarity to the family of pyridine nucleotide-disulphide oxidoreductase. To analyse the physiological effect of transhydrogenation between the two coenzyme systems NADP(H) and NAD(H) during anaerobic growth, S. cerevisiae was transformed with a plasma membrane bound AB-transhydrogenase from E. coli and with a cytoplasmic BB-transhydrogenase from A. vinelandii. Expression of both types changed the intracellular nucleotide levels. The NADPH/NADP{sup +} ratio was reduced while the NADH/NAD{sup +} ratio was almost constant. An increased formation of 2-oxoglutarate, glycerol and acetate was observed during anaerobic glucose fermentation 206 refs, 8 figs, 3 tabs

  15. Directed Evolution towards Increased Isoprenoid Production in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Carlsen, Simon; Nielsen, Michael Lynge

    Due to declining drug discovery rates from organic synthetic libraries, pharmaceutical companies are turning their attention towards secondary metabolites. Isoprenoids, also known as terpenoids, constitute the largest known group of secondary metabolites isolated to date, encompassing more than 55,000 different compounds including several blockbuster drugs such as paclitaxel and artemisinin. All molecules within this group are biosynthesized from the same precursor called isopentenyl pyrophosphate (IPP), which is repeatedly polymerized and diversified giving rise to enormous chemical and structural diversity. The most common way of producing these compounds is by organic synthesis. Organic synthesis does however have several disadvantages for production of secondary metabolites such as low yields due to the complex structures, which makes this way of production economically unfeasible. Microbial production can easily be scaled to meet current demands and it is also an environmental benign production method compared to organic synthesis. Thus it would be attractive to engineer a microorganism to produce high amounts of IPP and other immediate prenyl precursors such as geranyl pyrophosphate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate for large-scale microbial production of terpenoids. Saccharomyces cerevisiae was chosen as production platform due to its widespread use in industrial production and the waste number of molecular biology tools which is available for its manipulation. The effort for discovering new genetic perturbations, which would results in and increased production of isoprenoids by S. cerevisiae has been very limited. This project is focus on creating diversity within a lycopene producing S. cerevisiae strain by construction of gDNA-, cDNA-, and transposon-libraries. The diversified population of S. cerevisiae clones will afterwards be screened using the isoprenoid molecule lycopene as a model compound, hereby enabling the isolation of phenotypes producing higher amounts of isoprenoid. The property making lycopene ideal for screening is its system of 11 conjugated double bonds, which absorbs light within the visible range resulting in the red color of lycopene. This feature is the cause for the orange/red phenotype of S. cerevisiae strains transformed with the genes encoding lycopene and enables visual screening of yeast colonies, by searching for colonies with more intense red colony coloration which is the result of higher amount of lycopene is being produced and hence high amount of isoprenoid precursor being available. This will elucidate novel genetic targets for increasing isoprenoid production in S. cerevisiae

  16. Local Regulatory Variation in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available Naturally occurring sequence variation that affects gene expression is an important source of phenotypic differences among individuals within a species. We and others have previously shown that such regulatory variation can occur both at the same locus as the gene whose expression it affects (local regulatory variation and elsewhere in the genome at trans-acting factors. Here we present a detailed analysis of genome-wide local regulatory variation in Saccharomyces cerevisiae. We used genetic linkage analysis to show that nearly a quarter of all yeast genes contain local regulatory variation between two divergent strains. We measured allele-specific expression in a diploid hybrid of the two strains for 77 genes showing strong self-linkage and found that in 52%-78% of these genes, local regulatory variation acts directly in cis. We also experimentally confirmed one example in which local regulatory variation in the gene AMN1 acts in trans through a feedback loop. Genome-wide sequence analysis revealed that genes subject to local regulatory variation show increased polymorphism in the promoter regions, and that some but not all of this increase is due to polymorphisms in predicted transcription factor binding sites. Increased polymorphism was also found in the 3' untranslated regions of these genes. These findings point to the importance of cis-acting variation, but also suggest that there is a diverse set of mechanisms through which local variation can affect gene expression levels.

  17. Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Weinert, Brian Tate; Iesmantavicius, Vytautas

    2014-01-01

    Lysine acetylation is a frequently occurring posttranslational modification; however, little is known about the origin and regulation of most sites. Here we used quantitative mass spectrometry to analyze acetylation dynamics and stoichiometry in Saccharomyces cerevisiae. We found that acetylation accumulated in growth-arrested cells in a manner that depended on acetyl-CoA generation in distinct subcellular compartments. Mitochondrial acetylation levels correlated with acetyl-CoA concentration in vivo and acetyl-CoA acetylated lysine residues nonenzymatically in vitro. We developed a method to estimate acetylation stoichiometry and found that the vast majority of mitochondrial and cytoplasmic acetylation had a very low stoichiometry. However, mitochondrial acetylation occurred at a significantly higher basal level than cytoplasmic acetylation, consistent with the distinct acetylation dynamics and higher acetyl-CoA concentration in mitochondria. High stoichiometry acetylation occurred mostly on histones, proteins present in histone acetyltransferase and deacetylase complexes, and on transcription factors. These data show that a majority of acetylation occurs at very low levels in exponentially growing yeast and is uniformly affected by exposure to acetyl-CoA.

  18. Switching the mode of sucrose utilization by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Miletti Luiz C

    2008-02-01

    Full Text Available Abstract Background Overflow metabolism is an undesirable characteristic of aerobic cultures of Saccharomyces cerevisiae during biomass-directed processes. It results from elevated sugar consumption rates that cause a high substrate conversion to ethanol and other bi-products, severely affecting cell physiology, bioprocess performance, and biomass yields. Fed-batch culture, where sucrose consumption rates are controlled by the external addition of sugar aiming at its low concentrations in the fermentor, is the classical bioprocessing alternative to prevent sugar fermentation by yeasts. However, fed-batch fermentations present drawbacks that could be overcome by simpler batch cultures at relatively high (e.g. 20 g/L initial sugar concentrations. In this study, a S. cerevisiae strain lacking invertase activity was engineered to transport sucrose into the cells through a low-affinity and low-capacity sucrose-H+ symport activity, and the growth kinetics and biomass yields on sucrose analyzed using simple batch cultures. Results We have deleted from the genome of a S. cerevisiae strain lacking invertase the high-affinity sucrose-H+ symporter encoded by the AGT1 gene. This strain could still grow efficiently on sucrose due to a low-affinity and low-capacity sucrose-H+ symport activity mediated by the MALx1 maltose permeases, and its further intracellular hydrolysis by cytoplasmic maltases. Although sucrose consumption by this engineered yeast strain was slower than with the parental yeast strain, the cells grew efficiently on sucrose due to an increased respiration of the carbon source. Consequently, this engineered yeast strain produced less ethanol and 1.5 to 2 times more biomass when cultivated in simple batch mode using 20 g/L sucrose as the carbon source. Conclusion Higher cell densities during batch cultures on 20 g/L sucrose were achieved by using a S. cerevisiae strain engineered in the sucrose uptake system. Such result was accomplished by effectively reducing sucrose uptake by the yeast cells, avoiding overflow metabolism, with the concomitant reduction in ethanol production. The use of this modified yeast strain in simpler batch culture mode can be a viable option to more complicated traditional sucrose-limited fed-batch cultures for biomass-directed processes of S. cerevisiae.

  19. Regulation of xylose metabolism in recombinant Saccharomyces cerevisiae

    OpenAIRE

    Penttilä Merja; Pitkänen Juha-Pekka; Soliymani Rabah; Kankainen Matti; Salusjärvi Laura; Ruohonen Laura

    2008-01-01

    Abstract Background Considerable interest in the bioconversion of lignocellulosic biomass into ethanol has led to metabolic engineering of Saccharomyces cerevisiae for fermentation of xylose. In the present study, the transcriptome and proteome of recombinant, xylose-utilising S. cerevisiae grown in aerobic batch cultures on xylose were compared with those of glucose-grown cells both in glucose repressed and derepressed states. The aim was to study at the genome-wide level how signalling and ...

  20. Adaptive evolution of a lactose-consuming saccharomyces cerevisiae recombinant

    OpenAIRE

    Guimarães, Pedro M. R.; François, J.; Parrou, J. L.; Teixeira, J. A.; Domingues, Lucília

    2007-01-01

    The construction of Saccharomyces cerevisiae strains with the ability to efficiently ferment lactose has biotechnological interest, particularly for the alcoholic fermentation of cheese whey (a high pollutant by-product of dairy industries). A flocculent lactoseconsuming S. cerevisiae recombinant expressing the LAC12 (lactose permease) and LAC4 (beta-galactosidase) genes of Kluyveromyces lactis was previously constructed, but presented poor efficiency in the fermentation of lactose. Thus, it ...

  1. Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation

    OpenAIRE

    Domingues, Lucília; Guimarães, Pedro M. R.; Oliveira, Carla Cristina Marques de

    2010-01-01

    Lactose is an interesting carbon source for the production of several bio-products by fermentation, primarily because it is the major component of cheese whey, the main by-product of dairy activities. However, the microorganism more widely used in industrial fermentation processes, the yeast Saccharomyces cerevisiae, does not have a lactose metabolization system. Therefore, several metabolic engineering approaches have been used to construct lactose-consuming S. cerevisiae strains, particular...

  2. Genomic Evolution of Saccharomyces cerevisiae under Chinese Rice Wine Fermentation

    OpenAIRE

    Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

    2014-01-01

    Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bio...

  3. Research on biosorption of uranium by saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The effects of pH and the granularity of S. cerevisiae on the biosorption capacity were examined in order to study the properties of the biosorption of uranium from effluent by Saccharomyces cerevisiae. The isotherm was drawn. From the isotherm, the equations of Langmuir and Freundlich were achieved. The results showed the highest biosorption capacity was obtained when the pH value was about 6 and the granularity was 0.15-0.13 mm

  4. DNA polymerases delta and epsilon are required for chromosomal replication in Saccharomyces cerevisiae.

    OpenAIRE

    Budd, M E; Campbell, J. L.

    1993-01-01

    Three DNA polymerases, alpha, delta, and epsilon are required for viability in Saccharomyces cerevisiae. We have investigated whether DNA polymerases epsilon and delta are required for DNA replication. Two temperature-sensitive mutations in the POL2 gene, encoding DNA polymerase epsilon, have been identified by using the plasmid shuffle technique. Alkaline sucrose gradient analysis of DNA synthesis products in the mutant strains shows that no chromosomal-size DNA is formed after shift of an a...

  5. Synthesis of Novel Lipids in Saccharomyces cerevisiae by Heterologous Expression of an Unspecific Bacterial Acyltransferase

    OpenAIRE

    Kalscheuer, Rainer; Luftmann, Heinrich; Steinbüchel, Alexander

    2004-01-01

    The bifunctional wax ester synthase/acyl-coenzyme A:diacylglycerol acyltransferase (WS/DGAT) is the key enzyme in storage lipid accumulation in the gram-negative bacterium Acinetobacter calcoaceticus ADP1, mediating wax ester, and to a lesser extent, triacylglycerol (TAG) biosynthesis. Saccharomyces cerevisiae accumulates TAGs and steryl esters as storage lipids. Four genes encoding a DGAT (Dga1p), a phospholipid:diacylglycerol acyltransferase (Lro1p) and two acyl-coenzyme A:sterol acyltransf...

  6. Intracellular expression of toxic shock syndrome toxin 1 in Saccharomyces cerevisiae.

    OpenAIRE

    Deresiewicz, R L; Flaxenburg, J A; Chan, M.; R.W. Finberg; Kasper, D L

    1994-01-01

    In order to search for an occult cytotoxic enzymatic activity of the toxic shock syndrome toxin 1 (TSST-1), we placed the gene encoding TSST-1 (tstH) under the control of an inducible promoter in the eukaryotic yeast Saccharomyces cerevisiae. Under similar circumstances, the known bacterial enzymatic cytotoxins Shiga-like toxin and diphtheria toxin are both highly lethal to the yeast host. Although full-length stable TSST-1 was demonstrated within the yeast cells and although it retained mito...

  7. Spermidine or spermine is essential for the aerobic growth of Saccharomyces cerevisiae.

    OpenAIRE

    Balasundaram, D; Tabor, C W; Tabor, H.

    1991-01-01

    A null mutation in the SPE2 gene of Saccharomyces cerevisiae, encoding S-adenosylmethionine decarboxylase, results in cells with no detectable S-adenosylmethionine decarboxylase, spermidine, and spermine. This mutant has an absolute requirement for spermidine or spermine for growth; this requirement is not satisfied by putrescine. Polyamine-depleted cells show a number of microscopic abnormalities that are similar to those reported for several cell division cycle (cdc) and actin mutants. Thes...

  8. Inositol and Phosphate Regulate GIT1 Transcription and Glycerophosphoinositol Incorporation in Saccharomyces cerevisiae

    OpenAIRE

    Almaguer, C.; Mantella, D.; Perez, E.; Patton-Vogt, J.

    2003-01-01

    Glycerophosphoinositol is produced through deacylation of the essential phospholipid phosphatidylinositol. In Saccharomyces cerevisiae, the glycerophosphoinositol produced is excreted from the cell but is recycled for phosphatidylinositol synthesis when inositol is limiting. To be recycled, glycerophosphoinositol enters the cell through the permease encoded by GIT1. The transport of exogenous glycerophosphoinositol through Git1p is sufficiently robust to support the growth of an inositol auxo...

  9. Regulation of the urea active transporter gene (DUR3) in Saccharomyces cerevisiae.

    OpenAIRE

    ElBerry, H M; Majumdar, M L; Cunningham, T S; Sumrada, R A; Cooper, T G

    1993-01-01

    The DUR3 gene, which encodes a component required for active transport of urea in Saccharomyces cerevisiae, has been isolated, and its sequence has been determined. The deduced DUR3 protein profile possesses alternating hydrophobic and hydrophilic regions characteristics of integral membrane proteins. Strong negative complementation observed during genetic analysis of the DUR3 locus suggests that the DUR3 product may polymerize to carry out its physiological function. Expression of DUR3 is re...

  10. Identification of the ureidoglycolate hydrolase gene in the DAL gene cluster of Saccharomyces cerevisiae.

    OpenAIRE

    Yoo, H S; Genbauffe, F S; Cooper, T G

    1985-01-01

    This report describes the isolation of the genes encoding allantoicase (DAL2) and ureidoglycolate hydrolase (DAL3), which are components of the large DAL gene cluster on the right arm of chromosome IX of Saccharomyces cerevisiae. During this work a new gene (DAL7) was identified and found to be regulated in the manner expected for an allantoin pathway gene. Its expression was (i) induced by allophanate, (ii) sensitive to nitrogen catabolite repression, and (iii) responsive to mutation of the ...

  11. Dual Luciferase Assay System for Rapid Assessment of Gene Expression in Saccharomyces cerevisiae

    OpenAIRE

    McNabb, David S.; Reed, Robin; Robert A. Marciniak

    2005-01-01

    A new reporter system has been developed for quantifying gene expression in the yeast Saccharomyces cerevisiae. The system relies on two different reporter genes, Renilla and firefly luciferase, to evaluate regulated gene expression. The gene encoding Renilla luciferase is fused to a constitutive promoter (PGK1 or SPT15) and integrated into the yeast genome at the CAN1 locus as a control for normalizing the assay. The firefly luciferase gene is fused to the test promoter and integrated into t...

  12. The STF2p Hydrophilin from Saccharomyces cerevisiae Is Required for Dehydration Stress Tolerance

    OpenAIRE

    López-Martínez, Gema; Rodríguez-Porrata, Boris; Margalef-Català, Mar; Cordero-Otero, Ricardo

    2012-01-01

    The yeast Saccharomyces cerevisiae is able to overcome cell dehydration; cell metabolic activity is arrested during this period but restarts after rehydration. The yeast genes encoding hydrophilin proteins were characterised to determine their roles in the dehydration-resistant phenotype, and STF2p was found to be a hydrophilin that is essential for survival after the desiccation-rehydration process. Deletion of STF2 promotes the production of reactive oxygen species and apoptotic cell death ...

  13. Regulation of xylose metabolism in recombinant Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Penttilä Merja

    2008-06-01

    Full Text Available Abstract Background Considerable interest in the bioconversion of lignocellulosic biomass into ethanol has led to metabolic engineering of Saccharomyces cerevisiae for fermentation of xylose. In the present study, the transcriptome and proteome of recombinant, xylose-utilising S. cerevisiae grown in aerobic batch cultures on xylose were compared with those of glucose-grown cells both in glucose repressed and derepressed states. The aim was to study at the genome-wide level how signalling and carbon catabolite repression differ in cells grown on either glucose or xylose. The more detailed knowledge whether xylose is sensed as a fermentable carbon source, capable of catabolite repression like glucose, or is rather recognised as a non-fermentable carbon source is important for further engineering this yeast for more efficient anaerobic fermentation of xylose. Results Genes encoding respiratory proteins, proteins of the tricarboxylic acid and glyoxylate cycles, and gluconeogenesis were only partially repressed by xylose, similar to the genes encoding their transcriptional regulators HAP4, CAT8 and SIP1-2 and 4. Several genes that are repressed via the Snf1p/Mig1p-pathway during growth on glucose had higher expression in the cells grown on xylose than in the glucose repressed cells but lower than in the glucose derepressed cells. The observed expression profiles of the transcription repressor RGT1 and its target genes HXT2-3, encoding hexose transporters suggested that extracellular xylose was sensed by the glucose sensors Rgt2p and Snf3p. Proteome analyses revealed distinct patterns in phosphorylation of hexokinase 2, glucokinase and enolase isoenzymes in the xylose- and glucose-grown cells. Conclusion The results indicate that the metabolism of yeast growing on xylose corresponds neither to that of fully glucose repressed cells nor that of derepressed cells. This may be one of the major reasons for the suboptimal fermentation of xylose by recombinant S. cerevisiae strains. Phosphorylation of different isoforms of glycolytic enzymes suggests that regulation of glycolysis also occurred at a post-translational level, supporting prior findings.

  14. In vitro screening of probiotic properties of Saccharomyces cerevisiae var. boulardii and food-borne Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    van der Aa Kuhle, Alis; Skovgaard, Kerstin; Jespersen, Lene

    2005-01-01

    The probiotic potential of IS Saccharomyces cerevisiae strains used for production of foods or bevel-ages or isolated from such, and eight strains of Saccharomyces cerevisiae var. boulardii, was investigated. All strains included were able to withstand pH 2.5 and 0.3% Ox-all. Adhesion to the nontumorigenic porcine jejunal epithelial cell line (IPEC-J2) was investigated by incorporation of H-3-methionine into the yeast cells and use of liquid scintillation counting. Only few of the food-borne S. ...

  15. Divergence in wine characteristics produced by wild and domesticated strains of Saccharomyces cerevisiae

    OpenAIRE

    Hyma, Katie E; Saerens, Sofie M; Verstrepen, Kevin J.; Fay, Justin C.

    2011-01-01

    The budding yeast Saccharomyces cerevisiae is the primary species used by wine makers to convert sugar into alcohol during wine fermentation. Saccharomyces cerevisiae is found in vineyards, but is also found in association with oak trees and other natural sources. Although wild strains of S. cerevisiae as well as other Saccharomyces species are also capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine, consistent with the idea t...

  16. Potential of a Saccharomyces cerevisiae recombinant strain lacking ethanol and glycerol biosynthesis pathways in efficient anaerobic bioproduction

    OpenAIRE

    Hirasawa, Takashi; Ida, Yoshihiro; Furuasawa, Chikara; SHIMIZU, Hiroshi

    2013-01-01

    Saccharomyces cerevisiae shows high growth activity under low pH conditions and can be used for producing acidic chemicals such as organic acids as well as fuel ethanol. However, ethanol can also be a problematic by-product in the production of chemicals except for ethanol. We have reported that a stable low-ethanol production phenotype was achieved by disrupting 6 NADH-dependent alcohol dehydrogenase genes of S. cerevisiae. Moreover, the genes encoding the NADH-dependent glycerol biosynthesi...

  17. Interaction between Hanseniaspora uvarum and Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Wang, Chunxiao; Mas, Albert; Esteve-Zarzoso, Braulio

    2015-08-01

    During wine fermentation, Saccharomyces clearly dominate over non-Saccharomyces wine yeasts, and several factors could be related to this dominance. However, the main factor causing the reduction of cultivable non-Saccharomyces populations has not yet been fully established. In the present study, various single and mixed fermentations were performed to evaluate some of the factors likely responsible for the interaction between Saccharomyces cerevisiae and Hanseniaspora uvarum. Alcoholic fermentation was performed in compartmented experimental set ups with ratios of 1:1 and 1:9 and the cultivable population of both species was followed. The cultivable H. uvarum population decreased sharply at late stages when S. cerevisiae was present in the other compartment, similarly to alcoholic fermentations in non-compartmented vessels. Thus, cell-to-cell contact did not seem to be the main cause for the lack of cultivability of H. uvarum. Other compounds related to fermentation performance (such as sugar and ethanol) and/or certain metabolites secreted by S. cerevisiae could be related to the sharp decrease in H. uvarum cultivability. When these factors were analyzed, it was confirmed that metabolites from S. cerevisiae induced lack of cultivability in H. uvarum, however ethanol and other possible compounds did not seem to induce this effect but played some role during the process. This study contributes to a new understanding of the lack of cultivability of H. uvarum populations during the late stages of wine fermentation. PMID:25956738

  18. Novel type of pheromone-induced invasion of Saccharomyces cerevisiae.

    Czech Academy of Sciences Publication Activity Database

    Frýdlová, Ivana; Basler, Marek; Malcová-Janatová, Ivana; Vašicová, Pavla; Hašek, Ji?í

    Dorchester : Wiley, 2007, s. 108-108. [International Conference on Yeast Genetics and Molecular Biology /23./. Melbourne (AU), 01.07.2007-06.07.2007] Institutional research plan: CEZ:AV0Z50200510 Keywords : saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  19. Morphology and physiology of colonies of wild Saccharomyces cerevisiae strains.

    Czech Academy of Sciences Publication Activity Database

    Š?oví?ek, V.; Váchová, Libuše; Palková, Z.

    Manchester, 2005, S56. [International Conference on Yeast Genetics and Molecular Biology /22./. Bratislava (SK), 07.08.2005-12.08.2005] R&D Projects: GA ?R GD204/03/H066; GA AV ?R IAA500200506 Institutional research plan: CEZ:AV0Z50200510 Keywords : saccharomyces cerevisiae * morphology Subject RIV: EE - Microbiology, Virology

  20. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells.

    Czech Academy of Sciences Publication Activity Database

    Šafa?ík, Ivo; Mad?rová, Zde?ka; Šafa?íková, Miroslava

    2008-01-01

    Ro?. 56, - (2008), s. 7925-7928. ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  1. In vitro screening of probiotic properties of Saccharomyces cerevisiae var. boulardii and food-borne Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    van der Aa Kuhle, Alis; Skovgaard, Kerstin

    2005-01-01

    The probiotic potential of IS Saccharomyces cerevisiae strains used for production of foods or bevel-ages or isolated from such, and eight strains of Saccharomyces cerevisiae var. boulardii, was investigated. All strains included were able to withstand pH 2.5 and 0.3% Ox-all. Adhesion to the nontumorigenic porcine jejunal epithelial cell line (IPEC-J2) was investigated by incorporation of H-3-methionine into the yeast cells and use of liquid scintillation counting. Only few of the food-borne S. cerevisiae strains exhibited noteworthy adhesiveness with the strongest levels of adhesion (13.6-16.8%) recorded for two isolates from blue veined cheeses. Merely 25% of the S. cerevisiae var. boulardii strains displayed good adhesive properties (16.2-28.0%). The expression of the proinflammatory cytokine IL-1? decreased strikingly in IPEC-J2 cells exposed to a Shiga-like toxin 2e producing Escherichia coli strain when the cells were pre- and coincubated with S. cerevisiae var. boulardii even though this yeast strain was low adhesive (5.4%), suggesting that adhesion is not a mandatory prerequisite for such a probiotic effect. A strain of S. cerevisiae isolated from West African sorghum beer exerted similar effects hence indicating that food-borne strains of S. cerevisiae may possess probiotic properties in spite of low adhesiveness. © 2004 Elsevier B.V. All rights reserved.

  2. Biosorption of 241Am by immobilized Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Americium-241 is one of the most serious radioactive contaminating nuclides due to its high toxicity and long half-life. The encouraging biosorption of 241Am from aqueous solutions by free Saccharomyces cerevisiae (S. cerevisiae) has been observed in our previous experiments. 241Am biosorption by immobilized S. cerevisiae and the effect of the various experimental conditions on the adsorption were investigated. The results indicated that the 241Am biosorption by immobilized S. cerevisiae is still very efficient, and immobilized S. cerevisiae can be used repeatedly or continuously. The biosorption equilibrium was achieved within 2 hours, and more than 92% of 241Am was removed by immobilized S. cerevisiae in the pH 1-4 range. No significant differences in 241Am biosorption were observed at 15-45 deg C. The immobilized S. cerevisiae, even after used repeatedly for 6 times, still could adsorb more than 90% of 241Am in solutions of 1.08 MBq/l (8.5 ?g/l). At this moment, the total adsorption capacity for 241Am was more than 63.3 KBq/g globe (0.5 ?g/g), but has not reached saturation yet. The 241Am left in solutions with initial concentration of 1.08 MBq/l (8.5 ?g/l) was noted as low as ?10 Bq/l (?8.0 x 10-5 ?g/l) after adsorption by the immobilized S. cerevisiae for 3 times. (author)

  3. Potential immobilized Saccharomyces cerevisiae as heavy metal removal

    Science.gov (United States)

    Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

    2015-05-01

    Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

  4. Genetic diversity study of the yeast Saccharomyces bayanus var. uvarum reveals introgressed subtelomeric Saccharomyces cerevisiae genes.

    Science.gov (United States)

    Naumova, Elena S; Naumov, Gennadi I; Michailova, Yulia V; Martynenko, Nikolay N; Masneuf-Pomarède, Isabelle

    2011-01-01

    Intraspecies polymorphism of the yeast Saccharomyces bayanus var. uvarum was studied using the polymerase chain reaction with a microsatellite primer (GTG)(5). Sixty-nine strains of different origins were analyzed. There existed a correlation between PCR patterns of the strains and the source of their isolation: the type of wine and the particular winemaking region. Southern hybridization analysis revealed for the first time introgression between Saccharomyces cerevisiae and S. bayanus var. uvarum. Two strains isolated from alcoholic beverages in Hungary and identified by genetic analysis as S. bayanus var. uvarum were found to harbor a number of S. cerevisiae subtelomeric sequences: Y', SUC, RTM and MAL. PMID:21112388

  5. Prezygotic reproductive isolation between Saccharomyces cerevisiae and Saccharomyces paradoxus

    OpenAIRE

    Greig Duncan; Maclean Calum J

    2008-01-01

    Abstract Background Matings between different Saccharomyces sensu stricto yeast species produce sexually sterile hybrids, so individuals should avoid mating with other species. Any mechanism that reduces the frequency of interspecific matings will confer a selective advantage. Here we test the ability of two closely-related Saccharomyces sensu stricto species to select their own species as mates and avoid hybridisation. Results We set up mate choice tests, using five independently isolated pa...

  6. Sit4p protein phosphatase is required for sensitivity of Saccharomyces cerevisiae to Kluyveromyces lactis zymocin.

    OpenAIRE

    Jablonowski, D; Butler, A. R.; Fichtner, L; Gardiner, D.; Schaffrath, R; Stark, M J

    2001-01-01

    We have identified two Saccharomyces cerevisiae genes that, in high copy, confer resistance to Kluyveromyces lactis zymocin, an inhibitor that blocks cells in the G(1) phase of the cell cycle prior to budding and DNA replication. One gene (GRX3) encodes a glutaredoxin and is likely to act at the level of zymocin entry into sensitive cells, while the other encodes Sap155p, one of a family of four related proteins that function positively and interdependently with the Sit4p protein phosphatase....

  7. Transcription of hexose transporters of Saccharomyces cerevisiae is affected by change in oxygen provision

    OpenAIRE

    Ruohonen Laura; Tamminen Anu; Wiebe Marilyn G; Rintala Eija; Penttilä Merja

    2008-01-01

    Abstract Background The gene family of hexose transporters in Saccharomyces cerevisiae consists of 20 members; 18 genes encoding transporters (HXT1-HXT17, GAL2) and two genes encoding sensors (SNF3, RGT2). The effect of oxygen provision on the expression of these genes was studied in glucose-limited chemostat cultivations (D = 0.10 h-1, pH 5, 30°C). Transcript levels were measured from cells grown in five steady state oxygen levels (0, 0.5, 1, 2.8 and 20.9% O2), and from cells under condition...

  8. Electrical stimulation of saccharomyces cerevisiae cultures / Estimulação elétrica de células de Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Ofelia Q.F., Araújo; Maria Alice Z., Coelho; Isabel C.P., Margarit; Carlos A., Vaz-Junior; Maria Helena M., Rocha-Leão.

    2004-06-01

    Full Text Available Modulação do potencial de membrana celular endógeno por um campo elétrico externo influencia a estrutura e função dos compartimentos da membrana, de suas proteínas e da bi-camada lipídica. Neste trabalho, os efeitos da aplicação de potencial no crescimento de Saccharomyces cerevisiae foram caracteri [...] zados por experimentos simples, mas conclusivos. O perfil temporal de crescimento celular e a divisão celular foram investigados como respostas macroscópicas ao estímulo elétrico. Experimentos controle foram conduzidos em condições idênticas, exceto pela ausência de potencial aplicado. Através de análise comparativa, verificou-se que o estímulo elétrico alterou o ciclo celular como foi possível observar através da medida da dispersão de tamanho celular de cada população, sugerindo um possível sincronismo na divisão celular. Análise do espectro de potência foi empregada para sustentar o aumento no sincronismo, e uma modelagem matemática foi conduzida para determinar mudanças na cinética de crescimento celular. Parâmetros cinéticos do modelo tipo Monod para crescimento foram determinados por regressão não-linear. A constante de afinidade (a saber, K S) apresentou uma dependência com o potencial aplicado, sugerindo mudanças no transporte através da membrana celular. Verificou-se, também, que o estresse promovido eletroquimicamente inibiu o crescimento e induziu mudanças na viabilidade celular. Abstract in english Modulation of cell endogenous membrane potential by an external electrical field influences the structure and function of membrane compartments, proteins and lipid bi-layer. In this work, the effects of applied potential on Saccharomyces cerevisiae growth were characterized through simple yet conclu [...] sive experiments. Cell growth time profile and cell division were investigated as macroscopic response to the electrical stimulation. Control experiments were conducted under identical conditions except for the absence of applied potential. Through comparative analysis, electrical stimulation was verified to alter cell cycle as smaller sized population was observed, suggesting that a synchrony in cell division was promoted. Power spectral analysis was employed to sustain synchrony enhancement, and mathematical modeling was conducted for determining kinetic growth changes. Monod type kinetic parameters for growth were determined by non-linear regression. The affinity constant (namely kS) presented a dependence on applied potential suggesting changes on transport across cell membrane. Electrochemically promoted stress was also verified to inhibit growth as well as to induce changes on cell viability.

  9. Cooperative Regulation of DOG2, Encoding 2-Deoxyglucose-6-Phosphate Phosphatase, by Snf1 Kinase and the High-Osmolarity Glycerol–Mitogen-Activated Protein Kinase Cascade in Stress Responses of Saccharomyces cerevisiae

    OpenAIRE

    Tsujimoto, Yoshiyuki; Izawa, Shingo; Inoue, Yoshiharu

    2000-01-01

    We screened the genome of Saccharomyces cerevisiae for the genes responsive to oxidative stress by using the lacZ transposon-insertion library. As a result, we found that expression of the DOG2 gene coding for 2-deoxyglucose-6-phosphate phosphatase was induced by oxidative stress. The expression of DOG2 was also induced by osmotic stress. We found a putative cis element (STRE, a stress response element) in the DOG2 promoter adjacent to a consensus sequence to which the Mig1p repressor is know...

  10. KIN28 encodes a C-terminal domain kinase that controls mRNA transcription in Saccharomyces cerevisiae but lacks cyclin-dependent kinase-activating kinase (CAK) activity.

    OpenAIRE

    Cismowski, M J; Laff, G M; Solomon, M J; Reed, S I

    1995-01-01

    The Saccharomyces cerevisiae gene KIN28 is a member of the cyclin-dependent kinase (CDK) family. The Kin28 protein shares extensive sequence identity with the vertebrate CDK-activating kinase MO15 (Cdk7), which phosphorylates CDKs in vitro on a critical threonine residue. Kin28 and MO15 have recently been found to copurify with the transcription factor IIH (TFIIH) holoenzyme of yeast and human cells, respectively. Although TFIIH is capable of phosphorylating the C-terminal domain (CTD) of RNA...

  11. Development of a system for multicopy gene integration in Saccharomyces cerevisiae.

    Science.gov (United States)

    Semkiv, Marta V; Dmytruk, Kostyantyn V; Sibirny, Andriy A

    2016-01-01

    In this study we describe construction and evaluation of a vector for multicopy integration in yeast Saccharomyces cerevisiae. In this vector a modified selective marker and a reporter gene PHO8 (encoding alkaline phosphatase) were flanked with delta sequences of the Ty1 transposon. Modified by error-prone PCR version of selection marker kanMX4 was obtained from Escherichia coli clone with impaired geneticin (G418) resistance. The attenuation of kanMX4 gene provides an opportunity to select for explicitly multicopy integration of the module in S. cerevisiae using moderate (200mgL(-1)) antibiotic concentrations. The developed system provided integration of 3-10 copies of the module in the genome of S. cerevisiae. High copy integration events were confirmed by qRT-PCR, Southern hybridization and reporter enzyme activity measurements. PMID:26529647

  12. Evolutionary engineering of Saccharomyces cerevisiae for efficient aerobic xylose consumption.

    DEFF Research Database (Denmark)

    Scalcinati, Gionata; Otero, José Manuel

    2012-01-01

    Industrial biotechnology aims to develop robust microbial cell factories, such as Saccharomyces cerevisiae, to produce an array of added value chemicals presently dominated by petrochemical processes. Xylose is the second most abundant monosaccharide after glucose and the most prevalent pentose sugar found in lignocelluloses. Significant research efforts have focused on the metabolic engineering of S. cerevisiae for fast and efficient xylose utilization. This study aims to metabolically engineer S. cerevisiae, such that it can consume xylose as the exclusive substrate while maximizing carbon flux to biomass production. Such a platform may then be enhanced with complementary metabolic engineering strategies that couple biomass production with high value-added chemical. Saccharomyces cerevisiae, expressing xylose reductase, xylitol dehydrogenase and xylulose kinase, from the native xylose-metabolizing yeast Pichia stipitis, was constructed, followed by a directed evolution strategy to improve xylose utilizationrates. The resulting S. cerevisiae strain was capable of rapid growth and fast xylose consumption producing only biomass and negligible amount of byproducts. Transcriptional profiling of this strain was employed to further elucidate the observed physiology confirms a strongly up-regulated glyoxylate pathway enabling respiratory metabolism. The resulting strain is a desirable platform for the industrial production of biomass-related products using xylose as a sole carbon source.

  13. Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available Saccharomyces cerevisiae is predominantly found in association with human activities, particularly the production of alcoholic beverages. S. paradoxus, the closest known relative of S. cerevisiae, is commonly found on exudates and bark of deciduous trees and in associated soils. This has lead to the idea that S. cerevisiae is a domesticated species, specialized for the fermentation of alcoholic beverages, and isolates of S. cerevisiae from other sources simply represent migrants from these fermentations. We have surveyed DNA sequence diversity at five loci in 81 strains of S. cerevisiae that were isolated from a variety of human and natural fermentations as well as sources unrelated to alcoholic beverage production, such as tree exudates and immunocompromised patients. Diversity within vineyard strains and within saké strains is low, consistent with their status as domesticated stocks. The oldest lineages and the majority of variation are found in strains from sources unrelated to wine production. We propose a model whereby two specialized breeds of S. cerevisiae have been created, one for the production of grape wine and one for the production of saké wine. We estimate that these two breeds have remained isolated from one another for thousands of years, consistent with the earliest archeological evidence for winemaking. We conclude that although there are clearly strains of S. cerevisiae specialized for the production of alcoholic beverages, these have been derived from natural populations unassociated with alcoholic beverage production, rather than the opposite.

  14. The Acyl-CoA synthetases encoded within FAA1 and FAA4 in Saccharomyces cerevisiae function as components of the fatty acid transport system linking import, activation, and intracellular Utilization

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; Black, P N

    2001-01-01

    Exogenous long-chain fatty acids are activated to coenzyme A derivatives prior to metabolic utilization. In the yeast Saccharomyces cerevisiae, the activation of these compounds prior to metabolic utilization proceeds through the fatty acyl-CoA synthetases Faa1p and Faa4p. Faa1p or Faa4p are essential for long-chain fatty acid import, suggesting that one or both of these enzymes are components of the fatty acid transport system, which also includes Fat1p. By monitoring the intracellular accumulation of the fluorescent long-chain fatty acid analogue 4,4-difluoro-5-methyl-4-bora-3a,4a-diaza-s-indacene-3-dodecanoic acid, long-chain fatty acid transport was shown to be severely restricted in a faa1 Delta faa4 Delta strain. These data established for the first time a mechanistic linkage between the import and activation of exogenous fatty acids in yeast. To investigate this linkage further, oleoyl CoA levels were defined following incubation of wild type and mutant cells with limiting concentrations of exogenous oleate. These studies demonstrated oleoyl CoA levels were reduced to less than 10% wild-type levels in faa1 Delta and faa1 Delta faa4 Delta strains. Defects in metabolic utilization and intracellular trafficking were also found in the fatty acyl-CoA synthetase-deficient strains. The faa1 Delta faa4 Delta strain had a marked reduction in endogenous acyl-CoA pools, suggesting these enzymes play a role in maintenance of endogenous acyl-CoA pools, metabolism and trafficking. In addition, this strain had levels of in vivo beta-oxidation of exogenous oleate reduced 3-fold when compared with the isogenic parent. Northern analyses demonstrated an additional defect in fatty acid trafficking as FAA1 or FAA4 were required for the transcriptional regulation of the genes encoding the peroxisomal enzymes acyl-CoA oxidase (POX1) and medium-chain acyl-CoA synthetase (FAA2). These data support the hypothesis that fatty acyl-CoA synthetase (Faa1p or Faa4p) functions as a component of the fatty acid import system by linking import and activation of exogenous fatty acids to intracellular utilization and signaling.

  15. Sequence of the GLN1 gene of Saccharomyces cerevisiae: role of the upstream region in regulation of glutamine synthetase expression.

    OpenAIRE

    Minehart, P L; Magasanik, B

    1992-01-01

    The GLN1 gene, encoding glutamine synthetase in Saccharomyces cerevisiae, was sequenced, and its encoded polypeptide was shown to have significant homology to other eukaryotic glutamine synthetases. S1 analysis has defined the transcriptional start site of the gene. Upstream analysis of the gene using lacZ fusions has verified transcriptional control of the gene and has identified a nitrogen upstream activation sequence which is required for the increased transcription of GLN1 seen when gluta...

  16. Saccharomyces cerevisiae: a versatile eukaryotic system in virology

    Directory of Open Access Journals (Sweden)

    Breinig Tanja

    2007-10-01

    Full Text Available Abstract The yeast Saccharomyces cerevisiae is a well-established model system for understanding fundamental cellular processes relevant to higher eukaryotic organisms. Less known is its value for virus research, an area in which Saccharomyces cerevisiae has proven to be very fruitful as well. The present review will discuss the main achievements of yeast-based studies in basic and applied virus research. These include the analysis of the function of individual proteins from important pathogenic viruses, the elucidation of key processes in viral replication through the development of systems that allow the replication of higher eukayotic viruses in yeast, and the use of yeast in antiviral drug development and vaccine production.

  17. Influence of organic acids and organochlorinated insecticides on metabolism of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Pejin Dušanka J.

    2005-01-01

    Full Text Available Saccharomyces cerevisiae is exposed to different stress factors during the production: osmotic, temperature, oxidative. The response to these stresses is the adaptive mechanism of cells. The raw materials Saccharomyces cerevisiae is produced from, contain metabolism products of present microorganisms and protective agents used during the growth of sugar beet for example the influence of acetic and butyric acid and organochlorinated insecticides, lindan and heptachlor, on the metabolism of Saccharomyces cerevisiae was investigated and presented in this work. The mentioned compounds affect negatively the specific growth rate, yield, content of proteins, phosphorus, total ribonucleic acids. These compounds influence the increase of trechalose and glycogen content in the Saccharomyces cerevisiae cells.

  18. Isolation and characterization of a dinucleoside triphosphatase from Saccharomyces cerevisiae.

    OpenAIRE

    Brevet, A.; Chen, J.; Fromant, M; Blanquet, S.; Plateau, P

    1991-01-01

    An enzyme able to cleave dinucleoside triphosphates has been purified 3,750-fold from Saccharomyces cerevisiae. Contrary to the enzymes previously shown to catabolize Ap4A in yeast, this enzyme is a hydrolase rather than a phosphorylase. The dinucleoside triphosphatase molecular ratio estimated by gel filtration is 55,000. Dinucleoside triphosphatase activity is strongly stimulated by the presence of divalent cations. Mn2+ displays the strongest stimulating effect, followed by Mg2+, Co2+, Cd2...

  19. Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vemuri, Goutham; Eiteman, M.A; McEwen, J.E; Olsson, Lisbeth; Nielsen, Jens

    2007-01-01

    Respiratory metabolism plays an important role in energy production in the form of ATP in all aerobically growing cells. However, a limitation in respiratory capacity results in overflow metabolism, leading to the formation of byproducts, a phenomenon known as ‘‘overflow metabolism’’ or ‘‘the Crabtree effect.’’ The yeast Saccharomyces cerevisiae has served as an important model organism for studying the Crabtree effect. When subjected to increasing glycolytic fluxes under aerobic conditions, the...

  20. Genetic Analysis of Default Mating Behavior in Saccharomyces Cerevisiae

    OpenAIRE

    Dorer, R.; Boone, C (Christophe); Kimbrough, T.; Kim, J; Hartwell, L H

    1997-01-01

    Haploid Saccharomyces cerevisiae cells find each other during conjugation by orienting their growth toward each other along pheromone gradients (chemotropism). However, when their receptors are saturated for pheromone binding, yeast cells must select a mate by executing a default pathway in which they choose a mating partner at random. We previously demonstrated that this default pathway requires the SPA2 gene. In this report we show that the default mating pathway also requires the AXL1, FUS...

  1. Modelling Neurodegeneration in Saccharomyces Cerevisiae: Why Cook with Baker's Yeast?

    OpenAIRE

    Khurana, Vikram; Lindquist, Susan

    2010-01-01

    In ageing populations, neurodegenerative diseases increase in prevalence, exacting an enormous toll on individuals and their communities. Multiple complementary experimental approaches are needed to elucidate the mechanisms underlying these complex diseases and to develop novel therapeutics. Here, we describe why the budding yeast Saccharomyces cerevisiae has a unique role in the neurodegeneration armamentarium. As the best-understood and most readily analysed eukaryotic organism, S. cerevisi...

  2. Genome-scale reconstruction of the Saccharomyces cerevisiae metabolic network

    DEFF Research Database (Denmark)

    Förster, Jochen; Famili, I.; Fu, P.; Palsson, B.O.; Nielsen, Jens

    2003-01-01

    The metabolic network in the yeast Saccharomyces cerevisiae was reconstructed using currently available genomic, biochemical, and physiological information. The metabolic reactions were compartmentalized between the cytosol and the mitochondria, and transport steps between the compartments and the environment were included. A total of 708 structural open reading frames (ORFs) were accounted for in the reconstructed network, corresponding to 1035 metabolic reactions. Further, 140 reactions were i...

  3. Centromere DNA mutations induce a mitotic delay in Saccharomyces cerevisiae.

    OpenAIRE

    Spencer, F; Hieter, P.

    1992-01-01

    Cytological observations of animal cell mitoses have shown that the onset of anaphase is delayed when chromosome attachment to the spindle is spontaneously retarded or experimentally interrupted. This report demonstrates that a centromere DNA (CEN) mutation carried on a single chromosome can induce a cell cycle delay observed as retarded mitosis in the yeast Saccharomyces cerevisiae. A 31-base-pair deletion within centromere DNA element II (CDEII delta 31) that causes chromosome missegregatio...

  4. Alcoholic fermentation of lactose by engineered flocculent Saccharomyces cerevisiae

    OpenAIRE

    Guimarães, Pedro M. R.; Teixeira, J. A.; Domingues, Lucília

    2008-01-01

    The construction of Saccharomyces cerevisiae strains with the ability to ferment lactose has biotechnological interest, particularly for cheese whey fermentation to ethanol. Direct fermentation of whey to ethanol is generally not economically feasible because the low lactose content (ca. 5% w/v) results in low ethanol titre (2 – 3% v/v), making the distillation process too expensive. Concentration of whey lactose (e.g. by ultrafiltration) prior to fermentation is an option to obtain higher et...

  5. Kinetochore–microtubule interaction during S phase in Saccharomyces cerevisiae

    OpenAIRE

    Kitamura, Etsushi; Tanaka, Kozo; Kitamura, Yoko; Tanaka, Tomoyuki U

    2007-01-01

    In the budding yeast Saccharomyces cerevisiae, microtubule-organizing centers called spindle pole bodies (SPBs) are embedded in the nuclear envelope, which remains intact throughout the cell cycle (closed mitosis). Kinetochores are tethered to SPBs by microtubules during most of the cell cycle, including G1 and M phases; however, it has been a topic of debate whether microtubule interaction is constantly maintained or transiently disrupted during chromosome duplication. Here, we show that cen...

  6. Reversal of PCNA Ubiquitylation by Ubp10 in Saccharomyces cerevisiae

    OpenAIRE

    Gallego-Sánchez, Alfonso; Andrés, Sonia; Conde, Francisco; San Segundo, Pedro; Bueno, Avelino

    2012-01-01

    Regulation of PCNA ubiquitylation plays a key role in the tolerance to DNA damage in eukaryotes. Although the evolutionary conserved mechanism of PCNA ubiquitylation is well understood, the deubiquitylation of ubPCNA remains poorly characterized. Here, we show that the histone H2B K123 ubiquitin protease Ubp10 also deubiquitylates ubPCNA in Saccharomyces cerevisiae. Our results sustain that Ubp10-dependent deubiquitylation of the sliding clamp PCNA normally takes place during S phase, likely ...

  7. Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth; Gro Rejkjær Sørensen, Laura; Weiss Nielsen, Martin; Lisby, Michael; Folkesson, Sven Anders; Regenberg, Birgitte

    2014-01-01

    Biofilm-forming microorganisms switch between two forms: free-living planktonic and sessile multicellular. Sessile communities of yeast biofilms in liquid medium provide a primitive example of multicellularity and are clinically important because biofilms tend to have other growth characteristics than free-living cells. We investigated the genetic basis for yeast, Saccharomyces cerevisiae, biofilm on solid surfaces in liquid medium by screening a comprehensive deletion mutant collection in the S...

  8. The Snf1 Protein Kinase in the Yeast Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Usaite, Renata

    2008-01-01

    In yeast, Saccharomyces cerevisiae, the Snf1 protein kinase is primarily known as a key component of the glucose repression regulatory cascade. The Snf1 kinase is highly conserved among eukaryotes and its mammalian homolog AMPK is responsible for energy homeostasis in cells, organs and whole bodies. Failure in the AMPK regulatory cascade leads to metabolic disorders, such as obesity or type 2 diabetes. The knowledge about the Snf1 protein kinase remains to be of much interest in studying yeast c...

  9. Saccharomyces cerevisiae: a nomadic yeast with no niche?

    OpenAIRE

    Goddard, Matthew R; Greig, Duncan

    2015-01-01

    Different species are usually thought to have specific adaptations, which allow them to occupy different ecological niches. But recent neutral ecology theory suggests that species diversity can simply be the result of random sampling, due to finite population sizes and limited dispersal. Neutral models predict that species are not necessarily adapted to specific niches, but are functionally equivalent across a range of habitats. Here, we evaluate the ecology of Saccharomyces cerevisiae, one o...

  10. Molecular basis of cell integrity and morphogenesis in Saccharomyces cerevisiae.

    OpenAIRE

    Cid, V J; Durán, A.; Del Rey, F. (Fernando); Snyder, M P; Nombela, C; Sánchez, M.

    1995-01-01

    In fungi and many other organisms, a thick outer cell wall is responsible for determining the shape of the cell and for maintaining its integrity. The budding yeast Saccharomyces cerevisiae has been a useful model organism for the study of cell wall synthesis, and over the past few decades, many aspects of the composition, structure, and enzymology of the cell wall have been elucidated. The cell wall of budding yeasts is a complex and dynamic structure; its arrangement alters as the cell grow...

  11. Isolation and characterization of a Saccharomyces cerevisiae peptide transport gene.

    OpenAIRE

    Perry, J.R.; Basrai, M A; Steiner, H Y; Naider, F; Becker, J M

    1994-01-01

    We have cloned and characterized a Saccharomyces cerevisiae peptide transport gene (PTR2) isolated from a genomic DNA library by directly selecting for functional complementation of a peptide transport-deficient mutant. Deletion and frameshift mutageneses were used to localize the complementing activity to a 3.1-kbp region on the transforming plasmid. DNA sequencing of the complementing region identified an open reading frame spanning 1,803 bp. The deduced amino acid sequence predicts a hydro...

  12. Understanding the 3-hydroxypropionic acid tolerance mechanism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kildegaard, Kanchana Rueksomtawin; Juncker, Agnieszka; Hallstrom, Bjorn; Jensen, Niels Bjerg; Maury, Jerome; Nielsen, Jen; Förster, Jochen; Borodina, Irina

    2013-01-01

    3-Hydroxypropionic acid (3HP) is an important platform chemical that can be converted into other valuable chemicals such as acrylic acid and its derivatives that are used in baby diap ers, various plastics, and paints. With the oil and gas resources becoming limiting, biotechnolo gy offers a sustainable alternative for production of acrylic acid from renewable feedstocks. We are establishing Saccharomyces cerevisiae as an alternative host for 3HP production. However, 3HP also inhibits yeast grow...

  13. Adsorption and Interfacial Electron Transfer of Saccharomyces Cerevisiae

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thanulov

    2003-01-01

    We have studied the adsorption and electron-transfer dynamics of Saccharomyces cerevisiae (yeast) iso-l-cytochrome c adsorbed on Au(lll) electrodes in aqueous phosphate buffer media. This cytochrome possesses a thiol group dos e to the protein surface (Cysl02) suitable for linking the protein to gold without drastic protein unfolding. A comprehensive approach, based on linear sweep and differential pulse voltammetry, capacitance measurements, X-ray photoelectron spectroscopy (XPS) , in situscann...

  14. Defective Interference in the Killer System of Saccharomyces cerevisiae

    OpenAIRE

    Ridley, Susan Porter; Wickner, Reed B.

    1983-01-01

    The K1 killer virus (or plasmid) of Saccharomyces cerevisiae is a noninfectious double-stranded RNA genome found intracellularly packaged in an icosahedral capsid. This genome codes for a protein toxin and for resistance to that toxin. Defective interfering virus mutants are deletion derivatives of the killer virus double-stranded RNA genome; such mutants are called suppressive. Unlike strains carrying the wild-type genome, strains with these deletion derivatives are neither toxin producers n...

  15. The mannoprotein of Saccharomyces cerevisiae is an effective bioemulsifier.

    OpenAIRE

    Cameron, D R; Cooper, D. G.; Neufeld, R. J.

    1988-01-01

    The mannoprotein which is a major component of the cell wall of Saccharomyces cerevisiae is an effective bioemulsifier. Mannoprotein emulsifier was extracted in a high yield from whole cells of fresh bakers' yeast by two methods, by autoclaving in neutral citrate buffer and by digestion with Zymolase (Miles Laboratories; Toronto, Ontario, Canada), a beta-1,3-glucanase. Heat-extracted emulsifier was purified by ultrafiltration and contained approximately 44% carbohydrate (mannose) and 17% prot...

  16. Expression of bacterial mercuric ion reductase in Saccharomyces cerevisiae.

    OpenAIRE

    Rensing, C; Kües, U; Stahl, U.; Nies, D H; Friedrich, B

    1992-01-01

    The gene merA coding for bacterial mercuric ion reductase was cloned under the control of the yeast promoter for alcohol dehydrogenase I in the yeast-Escherichia coli shuttle plasmid pADH040-2 and transformed into Saccharomyces cerevisiae AH22. The resulting transformant harbored stable copies of the merA-containing hybrid plasmid, displayed a fivefold increase in the MIC of mercuric chloride, and synthesized mercuric ion reductase activity.

  17. P bodies promote stress granule assembly in Saccharomyces cerevisiae

    OpenAIRE

    Buchan, J. Ross; Muhlrad, Denise; Parker, Roy

    2008-01-01

    Recent results indicate that nontranslating mRNAs in eukaryotic cells exist in distinct biochemical states that accumulate in P bodies and stress granules, although the nature of interactions between these particles is unknown. We demonstrate in Saccharomyces cerevisiae that RNA granules with similar protein composition and assembly mechanisms as mammalian stress granules form during glucose deprivation. Stress granule assembly is dependent on P-body formation, whereas P-body assembly is inde...

  18. Supply of phosphatidylethanolamine to peroxisomes of Saccharomyces cerevisiae

    OpenAIRE

    Rosenberger, Sabine; Zellnig, Günther; Daum, Günther

    2007-01-01

    Phosphatidylethanolamine (PtdEtn) is an essential component of biological membranes. In the yeast Saccharomyces cerevisiae, PtdEtn is synthesized by three different pathways including decarboxylation of PtdSer by the mitochondrial phosphatidylserine decarboxylase Psd1p, or by Psd2p in a Golgi/vacuolar compartment. The third pathway, the so-called CDP- ethanolamine pathway, is located to the endoplasmic reticulum. After synthesis, PtdEtn is translocated to its proper destin...

  19. Distributive Disjunction of Authentic Chromosomes in Saccharomyces Cerevisiae

    OpenAIRE

    Guacci, V; Kaback, D B

    1991-01-01

    Distributive disjunction is defined as the first division meiotic segregation of either nonhomologous chromosomes that lack homologs or homologous chromosomes that have not recombined. To determine if chromosomes from the yeast Saccharomyces cerevisiae were capable of distributive disjunction, we constructed a strain that was monosomic for both chromosome I and chromosome III and analyzed the meiotic segregation of the two monosomic chromosomes. In addition, we bisected chromosome I into two ...

  20. Regulation of phospholipid synthesis in Saccharomyces cerevisiae by zinc depletion

    OpenAIRE

    CARMAN, George M.; Han, Gil-Soo

    2006-01-01

    The synthesis of phospholipids in the yeast Saccharomyces cerevisiae is regulated by zinc, an essential mineral required for growth and metabolism. Cells depleted of zinc contain increased levels of phosphatidylinositol and decreased levels of phosphatidylethanolamine. In addition to the major phospholipids, the levels of the minor phospholipids phosphatidate and diacylglycerol pyrophosphate decrease in the vacuole membrane of zinc-depleted cells. Alterations in phosphatidylinositol and phosp...

  1. Sensitivity of polyamine-deficient Saccharomyces cerevisiae to elevated temperatures.

    OpenAIRE

    Balasundaram, D; Tabor, C W; Tabor, H.

    1996-01-01

    Saccharomyces cerevisiae cells that cannot synthesize spermidine or spermine because of a deletion in the gene coding for S-adenosylmethionine decarboxylase are very sensitive to elevated temperatures when incubated in a polyamine-deficient medium; i.e., growth is inhibited and the cells are killed. This sensitivity is very pronounced at 39 degrees C, but a moderate effect is noted even at 33 to 34 degrees C. These findings support findings from other studies from our laboratory on the import...

  2. Shuttle mutagenesis: a method of transposon mutagenesis for Saccharomyces cerevisiae.

    OpenAIRE

    Seifert, H S; Chen, E Y; So, M.; Heffron, F

    1986-01-01

    We have extended the method of transposon mutagenesis to the eukaryote, Saccharomyces cerevisiae. A bacterial transposon containing a selectable yeast gene can be transposed into a cloned fragment of yeast DNA in Escherichia coli, and the transposon insertion can be returned to the yeast genome by homologous recombination. Initially, the cloned yeast DNA fragment to be mutagenized was transformed into an E. coli strain containing an F factor derivative carrying the transposable element. The c...

  3. Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation

    OpenAIRE

    Aslankoohi, Elham; Bo ZHU; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie; Courtin, Christophe M.; Verstrepen, Kevin J.

    2013-01-01

    The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all thr...

  4. Investigation of nutrient sensing in the yeast Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine

    2006-01-01

    Gæren Saccharomyces cerevisiae har udviklet komplekse regulatoriske systemer til at kontrollere ekspression af de proteiner, der importerer næringsstoffer, således at disse kun bliver produceret, når der er brug for dem. Dette er tilfældet for hexose-transportører samt aminosyre-transportører (disse bliver også kaldt amino acid permeases (AAPs)). Deres ekspression induceres på det transkriptionelle niveau efter at ekstracellulære næringsstoffer, henholdsvis glukose og aminosyrer, bliver detekter...

  5. Plasmid Accumulation Reduces Life Span in Saccharomyces cerevisiae*

    OpenAIRE

    Falcón, Alaric A.; Aris, John P.

    2003-01-01

    Aging in the yeast Saccharomyces cerevisiae is under the control of multiple pathways. The production and accumulation of extrachromosomal rDNA circles (ERCs) is one pathway that has been proposed to bring about aging in yeast. To test this proposal, we have developed a plasmid-based model system to study the role of DNA episomes in reduction of yeast life span. Recombinant plasmids containing different replication origins, cis-acting partitioning elements, and selectable marker genes were co...

  6. Impact of systems biology on metabolic engineering of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Nielsen, Jens; Jewett, Michael Christopher

    2008-01-01

    Industrial biotechnology is a rapidly growing field. With the increasing shift towards a bio-based economy, there is rising demand for developing efficient cell factories that can produce fuels, chemicals, pharmaceuticals, materials, nutraceuticals, and even food ingredients. The yeast Saccharomyces cerevisiae is extremely well suited for this objective. As one of the most intensely studied eukaryotic model organisms, a rich density of knowledge detailing its genetics, biochemistry, physiology, ...

  7. Applied systems biology - vanillin production in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Strucko, Tomas; Eriksen, Carsten; Nielsen, J.; Mortensen, Uffe Hasbro

    2012-01-01

    Vanillin is the most important aroma compound based on market value, and natural vanillin is extracted from the cured seed pods of the Vanilla orchid. Most of the world’s vanillin, however, is obtained by chemical synthesis from petrochemicals or wood pulp lignins. As an alternative, de novo biosynthesis of vanillin in baker’s yeast Saccharomyces cerevisiae was recently demonstrated by successfully introducing the metabolic pathway for vanillin production in yeast. Nevertheless, the amount of va...

  8. Heterologous Expression of Syntaxin 6 in Saccharomyces cerevisiae

    OpenAIRE

    MARTIN GÖTTE; ANDREA STADTBÄUMER

    2002-01-01

    The molecular mechanisms of vesicular protein transport in eukaryotic cells are highly conserved. Members of the syntaxin family play a pivotal role in the membrane fusion process. We have expressed rat syntaxin 6 and its cytoplasmic domain in wild-type and pep12 mutant strains of Saccharomyces cerevisiae to elucidate the role of the syntaxin 6-dependent vesicular trafficking step in yeast. Immunofluorescence microscopy revealed a punctate, Golgi-like staining pattern for syntaxin 6, which on...

  9. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation

    OpenAIRE

    Sun, Xiang-yu; Zhao, Yu; Liu, Ling-Ling; Bo JIA; Zhao, Fang; Huang, Wei-Dong; Zhan, Ji-cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation syst...

  10. Data mining tools for the Saccharomyces cerevisiae morphological database

    OpenAIRE

    Saito, Taro L.; Sese, Jun; Nakatani, Yoichiro; Sano, Fumi; Yukawa, Masashi; Ohya, Yoshikazu; Morishita, Shinichi

    2005-01-01

    For comprehensive understanding of precise morphological changes resulting from loss-of-function mutagenesis, a large collection of 1 899 247 cell images was assembled from 91 271 micrographs of 4782 budding yeast disruptants of non-lethal genes. All the cell images were processed computationally to measure ?500 morphological parameters in individual mutants. We have recently made this morphological quantitative data available to the public through the Saccharomyces cerevisiae Morphological D...

  11. The phenotypic landscape of a Saccharomyces cerevisiae strain collection

    OpenAIRE

    Mendes, In??s; Duarte, Ricardo Franco; Umek, Lan; Fonseca, Elza; Neves, J. Drumonde; Dequin, Sylvie; Zupan, Blaz; Schuller, Dorit

    2012-01-01

    Within our previous work [1] we developed computational models to predict strains with specific phenotypes (e.g. low ethanol resistance, growth at 30??C and growth in media containing galactose, raffinose or urea) from microsatellite allelic patterns. The objective of the present work was to gain deeper understanding of the phenotypic diversity of a heterogeneous Saccharomyces cerevisiae strain collection, using a large battery of tests with biotechnological relevance, and apply computational...

  12. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    The simple eukaryote Saccharomyces cerevisiae has proved to be a useful organism for elucidating the mechanisms that govern cell cycle progression in eukaryotic cells. The excellent in vivo system permits a cell cycle study using temperature sensitive mutants. In addition, it is possible to study many genes and gene products from higher eukaryotes in Saccharomyces cerevisiae because many genes and biological processes are homologous or similar in lower and in higher eukaryotes. The highly developed methods of genetics and molecular biology greatly facilitates studies of higher eukaryotic processes.Programmmed cell death with apoptosis plays a major role in development and homeostatis in most, if not all, animal cells. Apoptosis is a morphologically distinct form of death, that requires the activation of a highly regulated suicide program. Saccharomyces cerevisiae provides a new system in which apoptosis can be studied using the novel, temperature sensitive mutant, cdc77. The cdc77 cells are defective in a G1 process, and die show the characteristc signs of apoptosis: condensation of the chromatin, degradation of the inner nuclear membrane, dilation of the space between the nuclear membranes, condensation of the cytoplasm and degradation of DNA to 50kb fragmensts. It should be noted that in yeast, in contrast to higher eukaryotes, the nuclear membrane remain intact and the chromosomes remain uncondensed and invisible during mitosis. The cdc77 mutant exhibit a defect in initiation of DNA synthesis and a much prolonged DNA synthesis under semirestrictive conditions.

  13. Genome-scale reconstruction of the Saccharomyces cerevisiae metabolic network

    DEFF Research Database (Denmark)

    Förster, Jochen; Famili, I.

    2003-01-01

    The metabolic network in the yeast Saccharomyces cerevisiae was reconstructed using currently available genomic, biochemical, and physiological information. The metabolic reactions were compartmentalized between the cytosol and the mitochondria, and transport steps between the compartments and the environment were included. A total of 708 structural open reading frames (ORFs) were accounted for in the reconstructed network, corresponding to 1035 metabolic reactions. Further, 140 reactions were included on the basis of biochemical evidence resulting in a genome-scale reconstructed metabolic network containing 1175 metabolic reactions and 584 metabolites. The number of gene functions included in the reconstructed network corresponds to similar to16% of all characterized ORFs in S. cerevisiae. Using the reconstructed network, the metabolic capabilities of S. cerevisiae were calculated and compared with Escherichia coli. The reconstructed metabolic network is the first comprehensive network for a eukaryotic organism, and it may be used as the basis for in silico analysis of phenotypic functions.

  14. A Saccharomyces cerevisiae-based bioassay for assessing pesticide toxicity.

    Science.gov (United States)

    Estève, Karine; Poupot, C; Dabert, P; Mietton-Peuchot, M; Milisic, V

    2009-12-01

    This study evaluates the toxic effect of three pesticides (Azoxystrobin, Cymoxanil, and Diuron) on the yeast Saccharomyces cerevisiae for the development of a new bioassay based on inhibition of S. cerevisiae metabolic activity at the level of adenosine-5-triphosphate (ATP) synthesis, as compared with two different toxicity tests based on inhibition of Daphnia magna mobility (NF EN ISO 6341) and inhibition of Vibrio fisheri activity (NF EN ISO 11348). The S. cerevisiae bioassay is cheaper and 96 times faster than the D. magna toxicity bioassay, but has lower sensitivity. It is as fast as the V. fisheri bioassay and more sensitive. Thus, this new toxicity test can be proposed for rapid detection of pesticide residues in environmental samples as a complement to the more expensive and time-consuming D. magna toxicity test. PMID:19856193

  15. Saccharomyces cerevisiae en la fabricación del licor Cocuy. / Saccharomyces cerevisiae in the manufacturing of Cocuy liquor

    Scientific Electronic Library Online (English)

    F, Yegres; G, Fernández-Zeppenfeldt; CG, Padin; L, Rovero; N, Richard-Yegres.

    2003-01-01

    Full Text Available El licor "cocuy" es una bebida artesanal, producida por las comunidades rurales en el occidente de Venezuela mediante un proceso de fermentación y destilación del mosto extraído del Agave cocui. Este estudio fue enmarcado en el "Programa Agave" con el propósito de contribuir a rescatar esta activida [...] d productiva tradicional. En vista de la falta de información en relación al proceso autóctono se hicieron estudios de las levaduras fermentadoras, la optimización de la producción de etanol y la utilización del residuo de la destilación (vinaza) como medio de cultivo. Los aislados con mayor capacidad fermentativa fueron seleccionados e identificados mediante parámetros morfológicos y metabólicos. Se compararon los niveles de consumo de azúcar de las levaduras con mayor capacidad fermentativa. Se estudió el efecto de la adición del azúcar blanca comercial y/o del fosfato de amonio y en la producción de alcohol en el proceso artesanal. Las concentraciones de azúcares en el mosto se evaluaron por refractometría, y el contenido de alcohol del licor por hidrometría. La utilización de la vinaza para la producción de biomasa como un componente del medio de cultivo fue comparada con un medio sintético mediante medidas del peso seco de la biomasa. Se confirma el papel de Saccharomyces cerevisiae en el proceso fermentativo espontáneo. Los resultados in situ evidenciaron un efecto favorable de la elevación del contenido de azúcar (11 a 18°Brix) y de la adición de fosfato de amonio dibásico (0,2 g/l). En estas condiciones, el tiempo de fermentación del mosto se acortó y la producción de licor aumentó hasta un 92%. Se demostró la posibilidad de utilizar la vinaza como un componente para un medio de cultivo de esta levadura, para iniciar la fermentación y para la producción de biomasa como una fuente de nutrientes de alto valor nutritivo para aves de corral o caprinos. Se recomienda apoyar los esfuerzos para desarrollar de esta importante fuente de ingresos para los campesinos que habitan las zonas semi-áridas de los estados Falcón y Lara. Abstract in english Liquor cocuy is an alcoholic beverage produced by fermentation and a subsequent distillation process of Agave cocui juice by the communities northwest Venezuela. This study was included in the "Agave cocui Program", which purpose was to rescue this traditional productive activity. Due to the lack of [...] information about this native product fermentative yeasts, alcohol production optimization, and use of distillation residue (nasty wine) as culture medium was investigated. Isolates with the best fermentative capacity were selected and identified by morphological and metabolic studies. Sugars consumption of the yeast with highest fermentative capacity were compared. Effect of white commercial sugar and/or ammonium phosphate dibasic addition to juice was evaluated during the process. Sugars concentration was estimated with a refractometer, measurement of alcohol content of liquor with an hidrometer. The production of yeasts biomass grown in a broth with nasty wine was compared to that in a synthetic one by dry biomass weight determinations. The Saccharomyces cerevisiae role in the spontaneous fermentative process was confirmed. The results in situ proved the favorable effect of extra sugar (11 to 18°Brix) and ammonium phosphate (0,2 g/l). Fermentative period was reduced and liquor production was enhanced to 92%. Use of nasty wine was proposed to obtain yeasts biomass, as fermentation starter or as a source of high nutritive value for poultry and goat feeding. We recommend to support efforts to improve this local activity which represent an important source of income for the farmer at the semi-arid zone at the states of Falcón and Lara.

  16. Dihydroxyacetone detoxification in Saccharomyces cerevisiae involves formaldehyde dissimilation.

    Science.gov (United States)

    Molin, Mikael; Blomberg, Anders

    2006-05-01

    To investigate Saccharomyces cerevisiae physiology during growth on the conditionally toxic triose dihydroxyacetone (DHA), protein expression was studied in strains overexpressing either of the two dihydroxyacetone kinase isogenes, DAK1 or DAK2, that grow well utilizing DHA as a carbon and energy source. DHA metabolism was found mostly similar to ethanol utilization, involving a strong component of glucose derepression, but also involved DHA-specific regulatory changes. A specific and strong (10- to 30-fold induction of formaldehyde dehydrogenase, Fdhlp, indicated activation of the formaldehyde dissimilation pathway in DHA medium. The importance of this pathway was further supported by impaired adaptation to DHA growth and DHA survival in a glutathione-dependent formaldehyde dehydrogenase (SFA1) deletion mutant. Glutathione synthase (GSH1) deletion led to decreased DHA survival in agreement with the glutathione cofactor requirement for the SFA1-encoded activity. DHA toxicity did, however, not solely appear related to formaldehyde accumulation, because SFA1 overexpression only enhanced formaldehyde but not DHA tolerance. In further agreement with a low DHA-to-formaldehyde flux, GSH supplements in the low microM range also fully suppressed the DHA sensitivity of a gsh1Delta strain. Under growth reduction on high (100 mM) DHA medium we report increased levels of advanced glycation end-product (AGE) formation on total protein. Under these high-DHA conditions expression of several stress-related proteins, e.g. a heat-shock protein (Hsp104p) and the oxidative stress indicator, alkyl hydroperoxide reductase (Ahp1p) was also found induced. However, hallmark determinants of oxidative stress tolerance (e.g. YAP1, SKN7, HYR1/GPX3 and SOD2) were redundant for DHA tolerance, thus indicating mechanisms of DHA toxicity largely independent of central oxidative stress defence mechanisms. We conclude that mechanisms for DHA growth and detoxification appear complex and that the evolutionary strive to minimize detrimental effects of this intracellular metabolite links to both formaldehyde and glutathione metabolism. PMID:16677304

  17. Mechanisms of DNA repair, recombination and mutagenesis in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Full text. 1. It was confirmed that from the six DNA polymerases discovered in yeast cells, only DNA polymerases ?, ? and ? are engaged in dark repair of lesions caused by UV-light and MMS. DNA polymerase ? is involved in the repair of both types of lesions, while DNA polymerase ? and ? only in lesions caused by UV and MMS, respectively. Other polymerases are not involved or play only a minor role in repair. The results obtained are being prepared for publication. 2. Studies on the involvement of the three replicative DNA polymerases in mitotic gene conversion induced by mono- and bifunctional psoralens (and also by UV- light or MMS) revealed that DNA polymerases ? and ? are the main polymerases responsible for induced intragenic conversion. DNA polymerase ? seems to play minor role in this process. It is possible that DNA polymerase ? may also be involved in DNA repair synthesis but only in cases when the opening of new replication forks is necessary for repair. 3. Studies on the influence of mutations in the replicative and nonreplicative DNA polymerases on adaptive mutations in the cells of Saccharomyces cerevisiae were continued. We found that thermosensitive mutation in the POL2 gene encoding DNA polymerase ? increased the frequency of adaptive mutation in a similar manner as found earlier for DNA polymerase ?. A similar effect was observed also in strains with deletions in the MSH3 gene responsible for mismatch repair. Mutations in other DNA polymerases, including the essential DNA polymerase ? and the inessential DNA polymerases ? and ? revealed no effect on this process. Analysis of DNA sequences in the revertants showed that in all cases the obtained reversions resulted from a single nucleotide deletion most often in sequences having short homopolymer tracts. The results obtained suggest that errors arising during DNA elongation and their persistence in mutants deficient in mismatch repair activity seem to be the source of the adaptive mutation appearance in studied cells. (author)

  18. Regulation of Saccharomyces cerevisiae kinetochores by the type 1 phosphatase Glc7p

    OpenAIRE

    Sassoon, Ingrid; Fedor F. Severin; Andrews, Paul D.; Taba, Maria-Rita; Kaplan, Ken B.; Ashford, Anthony J.; Stark, Michael J.R.; Sorger, Peter K.; Hyman, Anthony A

    1999-01-01

    We have investigated the role of protein phosphorylation in regulation of Saccharomyces cerevisiae kinetochores. By use of phosphatase inhibitors and a type 1 protein phosphatase mutant (glc7-10), we show that the microtubule binding activity, but not the centromeric DNA-binding activity, of the kinetochore complex is regulated by a balance between a protein kinase and the type 1 protein phosphatase (PP1) encoded by the GLC7 gene. glc7-10 mutant cells exhibit low kinetochore-microtubule bindi...

  19. A DNA Helicase Required for Maintenance of the Functional Mitochondrial Genome in Saccharomyces cerevisiae

    OpenAIRE

    Sedman, Tiina; Kuusk, Silja; Kivi, Sirje; Sedman, Juhan

    2000-01-01

    A novel DNA helicase, a homolog of several prokaryotic helicases, including Escherichia coli Rep and UvrD proteins, is encoded by the Saccharomyces cerevisiae nuclear genome open reading frame YOL095c on the chromosome XV. Our data demonstrate that the helicase is localized in the yeast mitochondria and is loosely associated with the mitochondrial inner membrane during biochemical fractionation. The sequence of the C-terminal end of the 80-kDa helicase protein is similar to a typical N-termin...

  20. Cloning and characterization of the high-affinity cAMP phosphodiesterase of Saccharomyces cerevisiae.

    OpenAIRE

    Sass, P.; Field, J.; Nikawa, J; Toda, T.; Wigler, M.

    1986-01-01

    A gene, PDE2, has been cloned from the yeast Saccharomyces cerevisiae that, when present in high copy, reverses the phenotypic effects of RAS2Val19, a mutant form of the RAS2 gene that renders yeast cells sensitive to heat shock and starvation. It has previously been shown that the RAS proteins are potent activators of yeast adenylate cyclase. We report here that PDE2 encodes a high-affinity cAMP phosphodiesterase that shares sequence homology with animal cell phosphodiesterases. These result...

  1. Intron mutations affect splicing of Saccharomyces cerevisiae SUP53 precursor tRNA.

    OpenAIRE

    Strobel, M C; Abelson, J.

    1986-01-01

    The Saccharomyces cerevisiae amber suppressor tRNA gene SUP53 (a tRNALeu3 allele) was used to investigate the role of intron structure and sequence on precursor tRNA splicing in vivo and in vitro. This gene encodes a pre-tRNA which contains a 32-base intervening sequence. Two types of SUP53 intron mutants were constructed: ones with an internal deletion of the natural SUP53 intron and ones with a novel intron. These mutant genes were transcribed in vitro, and the end-processed transcripts wer...

  2. Ribosomal protein L30 is dispensable in the yeast Saccharomyces cerevisiae.

    OpenAIRE

    Baronas-Lowell, D M; Warner, J R

    1990-01-01

    In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, a...

  3. Molecular Genetics of Cryptopleurine Resistance in Saccharomyces Cerevisiae: Expression of a Ribosomal Protein Gene Family

    OpenAIRE

    Paulovich, A G; Thompson, J. R.; Larkin, J C; Li, Z.; Woolford-Jr., J. L.

    1993-01-01

    The Saccharomyces cerevisiae CRY1 gene encodes the 40S ribosomal subunit protein rp59 and confers sensitivity to the protein synthesis inhibitor cryptopleurine. A yeast strain containing the cry1-?1::URA3 null allele is viable, cryptopleurine sensitive (Cry(S)), and expresses rp59 mRNA, suggesting that there is a second functional CRY gene. The CRY2 gene has been isolated from a yeast genomic library cloned in bacteriophage ?, using a CRY1 DNA probe. The DNA sequence of the CRY2 gene contains...

  4. The REV1 gene of Saccharomyces cerevisiae: isolation, sequence, and functional analysis.

    OpenAIRE

    Larimer, F W; Perry, J.R.; Hardigree, A A

    1989-01-01

    The REV1 gene of Saccharomyces cerevisiae is required for normal induction of mutations by physical and chemical agents. We have determined the sequence of a 3,485-base-pair segment of DNA that complements the rev1-1 mutant. Gene disruption was used to confirm that this DNA contained the REV1 gene. The sequenced segment contains a single long open reading frame, which can encode a polypeptide of 985 amino acid residues. The REV1 transcript is 3.1 kilobase pairs in length. Frameshift mutations...

  5. Saccharomyces cerevisiae: a nomadic yeast with no niche?

    Science.gov (United States)

    Goddard, Matthew R; Greig, Duncan

    2015-05-01

    Different species are usually thought to have specific adaptations, which allow them to occupy different ecological niches. But recent neutral ecology theory suggests that species diversity can simply be the result of random sampling, due to finite population sizes and limited dispersal. Neutral models predict that species are not necessarily adapted to specific niches, but are functionally equivalent across a range of habitats. Here, we evaluate the ecology of Saccharomyces cerevisiae, one of the most important microbial species in human history. The artificial collection, concentration and fermentation of large volumes of fruit for alcohol production produce an environment in which S. cerevisiae thrives, and therefore it is assumed that fruit is the ecological niche that S. cerevisiae inhabits and has adapted to. We find very little direct evidence that S. cerevisiae is adapted to fruit, or indeed to any other specific niche. We propose instead a neutral nomad model for S. cerevisiae, which we believe should be used as the starting hypothesis in attempting to unravel the ecology of this important microbe. PMID:25725024

  6. Metabolic alterations during ascosporogenesis of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Sporulation of S. cerevisiae has been shown to alter the profiles of enzymes involved in gluconeogenesis and glycolysis. The enhancement in the levels of total cellular carbohydrates could be correlated with the enhancement in fructose 1,6-diphosphatase and trehalose-phosphate synthetase. The latter activity could account for the 15-fold increase in trehalose levels in sporulating cells. Glucose-6-phosphatase, pyruvate kinase and phosphofructokinase showed continuous decline during ascosporogenesis. The relative incorporation of radioactivity from possible precursors of gluconeogenesis indicated that acetate-2-14C alone could contribute to carbohydrate synthesis. (author)

  7. Biosorption of cesium by saccharomyces cerevisia

    International Nuclear Information System (INIS)

    The characteristics of Cs+ biosorption by Saccharornyces cerevisia was investigated, including the biosorption kinetics, biosorption equilibrium, isotherm as well as the IR spectrum of biomass pre- and post-biosorption. The experimental results show that the process of Cs+ biosorption onto the biomass of Saccharornyces cerevisia can be devided into two stages, the first stage is physical sorption and the sorption equilibrium is very quickly reached (within 20 min). The biosorption kinetics can be described by the pseudo second-order equation quite well (R2=0.989), the kinetic parameters k2 and qe are 3.56 x 10-3 g/(mg·min) and 7.18 mg/g, respectively. The equilibrium isotherm data can be fitted with Langmuir and Freundlich models, with the maximum biosorptive capacity of 10.13 mg/g. Both the IR spectra of the biomass pre- and post-biosorption almost are same, and it indicates that the biosorption of Cs+ does not change the structure of the biomass, however, some adsorptive peaks shift. (authors)

  8. Construction of killer industrial yeast Saccharomyces cerevisiae HAU-1 and its fermentation performance

    Scientific Electronic Library Online (English)

    Bijender K., Bajaj; S., Sharma.

    2010-06-01

    Full Text Available Saccharomyces cerevisiae HAU-1, a time tested industrial yeast possesses most of the desirable fermentation characteristics like fast growth and fermentation rate, osmotolerance, high ethanol tolerance, ability to ferment molasses, and to ferment at elevated temperatures etc. However, this yeast was [...] found to be sensitive against the killer strains of Saccharomyces cerevisiae. In the present study, killer trait was introduced into Saccharomyces cerevisiae HAU-1 by protoplast fusion with Saccharomyces cerevisiae MTCC 475, a killer strain. The resultant fusants were characterized for desirable fermentation characteristics. All the technologically important characteristics of distillery yeast Saccharomyces cerevisiae HAU-1 were retained in the fusants, and in addition the killer trait was also introduced into them. Further, the killer activity was found to be stably maintained during hostile conditions of ethanol fermentations in dextrose or molasses, and even during biomass recycling.

  9. Gains and Losses of Transcription Factor Binding Sites in Saccharomyces cerevisiae and Saccharomyces paradoxus.

    Science.gov (United States)

    Schaefke, Bernhard; Wang, Tzi-Yuan; Wang, Chuen-Yi; Li, Wen-Hsiung

    2015-08-01

    Gene expression evolution occurs through changes in cis- or trans-regulatory elements or both. Interactions between transcription factors (TFs) and their binding sites (TFBSs) constitute one of the most important points where these two regulatory components intersect. In this study, we investigated the evolution of TFBSs in the promoter regions of different Saccharomyces strains and species. We divided the promoter of a gene into the proximal region and the distal region, which are defined, respectively, as the 200-bp region upstream of the transcription starting site and as the 200-bp region upstream of the proximal region. We found that the predicted TFBSs in the proximal promoter regions tend to be evolutionarily more conserved than those in the distal promoter regions. Additionally, Saccharomyces cerevisiae strains used in the fermentation of alcoholic drinks have experienced more TFBS losses than gains compared with strains from other environments (wild strains, laboratory strains, and clinical strains). We also showed that differences in TFBSs correlate with the cis component of gene expression evolution between species (comparing S. cerevisiae and its sister species Saccharomyces paradoxus) and within species (comparing two closely related S. cerevisiae strains). PMID:26220934

  10. Saccharomyces cerevisiae and non-Saccharomyces yeasts in grape varieties of the São Francisco Valley

    Scientific Electronic Library Online (English)

    Camila M.P.B.S. de, Ponzzes-Gomes; Dângelly L.F.M. de, Mélo; Caroline A., Santana; Giuliano E., Pereira; Michelle O.C., Mendonça; Fátima C.O., Gomes; Evelyn S., Oliveira; Antonio M., Barbosa Jr; Rita C., Trindade; Carlos A., Rosa.

    2014-06-01

    Full Text Available The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisi [...] ae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 x 10(5) cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production.

  11. On cycles in the transcription network of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Berman Piotr

    2008-01-01

    Full Text Available Abstract Background We investigate the cycles in the transcription network of Saccharomyces cerevisiae. Unlike a similar network of Escherichia coli, it contains many cycles. We characterize properties of these cycles and their place in the regulatory mechanism of the cell. Results Almost all cycles in the transcription network of Saccharomyces cerevisiae are contained in a single strongly connected component, which we call LSCC (L for "largest", except for a single cycle of two transcription factors. The fact that LSCC includes almost all cycles is well explained by the properties of a random graph with the same in- and out-degrees of the nodes. Among different physiological conditions, cell cycle has the most significant relationship with LSCC, as the set of 64 transcription interactions that are active in all phases of the cell cycle has overlap of 27 with the interactions of LSCC (of which there are 49. Conversely, if we remove the interactions that are active in all phases of the cell cycle (25% of interactions to transcription factors, the LSCC would have only three nodes and 5 edges, many fewer than expected. This subgraph of the transcription network consists mostly of interactions that are active only in the stress response subnetwork. We also characterize the role of LSCC in the topology of the network. We show that LSCC can be used to define a natural hierarchy in the network and that in every physiological subnetwork LSCC plays a pivotal role. Conclusion Apart from those well-defined conditions, the transcription network of Saccharomyces cerevisiae is devoid of cycles. It was observed that two conditions that were studied and that have no cycles of their own are exogenous: diauxic shift and DNA repair, while cell cycle and sporulation are endogenous. We claim that in a certain sense (slow recovery stress response is endogenous as well.

  12. Protein expression of saccharomyces cerevisiae in response to uranium exposure

    International Nuclear Information System (INIS)

    Protein expression of Saccharomyces cerevisiae grown in the medium containing 238U (VI) and 233U (VI) was examined by two-dimensional gel electrophoresis. Saccharomyces cerevisiae of BY4743 was grown in yeast nitrogen base medium containing glucose and glycerol 2-phosphate and 238U of 0, 2.0, and 5.0 x 10-4 M or 233U of 2.5 x 10-6 M (radioactivity was higher by 350 times than 2.0 x 10-4 M 238U) and 5.0 x 10-6 M for 112 h at 30 degC. The growth of Saccharomyces cerevisiae was monitored by measuring OD600 at 112 h after the inoculation. Uranium concentrations in the media also were measured by radiometry using a liquid scintillation counter. The growths of the yeast grown in the above media were in the following order: control>2.5 x 10-6 M 233U>2.0 x 10-4 M 238U>5.0 x 10-6 M 233U>5.0 x 10-4 M 238U. This result indicated that not only radiological but also chemical effect of U reduced the growth of the yeast. The concentrations of U in the medium containing 238U or 233U decreased, suggesting U accumulation by the yeast cells. The 2-D gel electrophoresis analysis showed the appearance of several spots after exposure to 238U or to 233U but not in the control containing no uranium. These results show that the yeast cells exposed to U express several specific proteins. (author)

  13. Expression of Saccharomyces cerevisiae ?-glucoside transporters under different growth conditions

    Scientific Electronic Library Online (English)

    S. L., Alves Jr.; J. M., Thevelein; B. U., Stambuk.

    2014-03-01

    Full Text Available Important biotechnological processes depend on the efficient fermentation by Saccharomyces cerevisiae yeasts of starch hydrolysates rich in maltose and maltotriose. The rate-limiting step for fermentation of these ?-glucosides is the transport across the plasma membrane of the cells. In order to con [...] tribute to a better understanding of maltose and maltotriose metabolism by S. cerevisiae, we analyzed the expression of the main ? glucoside transporter genes in two different yeast strains grown on media with glucose, maltose or maltotriose as carbon source. Although both yeast strains have higher ?glucoside transport activity during growth on maltotriose, our results show similar expression levels of the analyzed genes on either maltose or maltrotriose media. Thus, our results indicate that, although the transport capacity of maltotriose grown cells is higher than that of maltose grown cells, maltotriose cannot be considered a better inducer of ?glucoside transporter genes.

  14. Understanding the 3-hydroxypropionic acid tolerance mechanism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kildegaard, Kanchana Rueksomtawin; Juncker, Agnieszka

    2013-01-01

    3-Hydroxypropionic acid (3HP) is an important platform chemical that can be converted into other valuable chemicals such as acrylic acid and its derivatives that are used in baby diap ers, various plastics, and paints. With the oil and gas resources becoming limiting, biotechnolo gy offers a sustainable alternative for production of acrylic acid from renewable feedstocks. We are establishing Saccharomyces cerevisiae as an alternative host for 3HP production. However, 3HP also inhibits yeast grow th at level well below what is desired for commercial applications. Therefore, we are aiming to improve 3HP tolerance in S. cerevisiae by applying adaptive evolution approach. We have generated yeast strains with sign ificantly improved capacity for tolerating 3HP when compared to the wild-type. We will present physiolo gical characterization, genome re-sequencing, and transcriptome analysis of the evolved strains. Conseq uently, mechanism underlying 3HP tolerance will be investigated.

  15. Glucose- and nitrogen sensing and regulatory mechanisms in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    RØdkaer, Steven V; Færgeman, Nils J.

    2014-01-01

    Pro- and eukaryotic cells are constantly challenged by varying concentrations of nutrients in their environment. Perceiving and adapting to such changes are therefore crucial for cellular viability. Thus, numerous specialized cellular receptors continuously sense and react to the availability of nutrients such as glucose and nitrogen. When stimulated, these receptors initiate various cellular signaling pathways, which in concert constitute a complex regulatory network. To ensure a highly specific response, these pathways and networks cross-communicate with each other and are regulated at several steps and by numerous different regulators. As numerous of these regulating proteins, biochemical mechanisms, and cellular pathways are evolutionary conserved, complex biochemical information relevant to humans can be obtained by studying simple organisms. Thus, the yeast Saccharomyces cerevisiae has been recognized as a powerful model system to study fundamental biochemical processes. In the present review, we highlight central signaling pathways and molecular circuits conferring nitrogen- and glucose sensing in S. cerevisiae.

  16. Use of Saccharomyces cerevisiae in radioactive waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Rafael Vicente de P.; Marumo, Julio T.; Bellini, Maria H.; Potiens Junior, Ademar J.; Takara, Aline S.; Goes, Marcos M. de; Borba, Tania R. de; Nascimento, Carina M. do; Sakata, Solange K. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: rpadua@ipen.br

    2007-07-01

    Waste management plays an important role in reducing the volume of radioactive waste streams, minimizing the cost of the final disposal and the impact on the environment. In this context, new research should focus on the development of simpler and cheaper techniques which may improve the waste processing. The use of biomass in processes concerned with the removal of heavy metals and radionuclides offers significant potential in the treatment of waste-liquid streams. Saccharomyces cerevisiae is well known for its capacity of heavy metals biosorption and it also has the additional advantages such as easy availability and the possibility of genetic manipulation. The aim of this work is to study the potential of the free cell and immobilized S. cerevisiae in bentonite in the removal Americium-241 from radioactive liquid streams produced by Radioactive Waste Laboratory of Nuclear and Energy Research Institute (IPEN-CNEN/SP). (author)

  17. Biosorption of heavy metals by Saccharomyces cerevisiae: a review.

    Science.gov (United States)

    Wang, Jianlong; Chen, Can

    2006-01-01

    Heavy metal pollution has become one of the most serious environmental problems today. Biosorption, using biomaterials such as bacteria, fungi, yeast and algae, is regarded as a cost-effective biotechnology for the treatment of high volume and low concentration complex wastewaters containing heavy metal(s) in the order of 1 to 100 mg/L. Among the promising biosorbents for heavy metal removal which have been researched during the past decades, Saccharomyces cerevisiae has received increasing attention due to the unique nature in spite of its mediocre capacity for metal uptake compared with other fungi. S. cerevisiae is widely used in food and beverage production, is easily cultivated using cheap media, is also a by-product in large quantity as a waste of the fermentation industry, and is easily manipulated at molecular level. The state of the art in the field of biosorption of heavy metals by S. cerevisiae not only in China, but also worldwide, is reviewed in this paper, based on a substantial number of relevant references published recently on the background of biosorption achievements and development. Characteristics of S. cerevisiae in heavy metal biosorption are extensively discussed. The yeast can be studied in various forms for different purposes. Metal-binding capacity for various heavy metals by S. cerevisiae under different conditions is compared. Lead and uranium, for instances, could be removed from dilute solutions more effectively in comparison with other metals. The yeast biosorption largely depends on parameters such as pH, the ratio of the initial metal ion and initial biomass concentration, culture conditions, presence of various ligands and competitive metal ions in solution and to a limited extent on temperature. An assessment of the isotherm equilibrium model, as well as kinetics was performed. The mechanisms of biosorption are understood only to a limited extent. Elucidation of the mechanism of metal uptake is a real challenge in the field of biosorption. Various mechanism assumptions of metal uptake by S. cerevisiae are summarized. PMID:16737792

  18. Magnetically altered ethanol fermentation capacity of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Galonja-Corghill Tamara

    2009-01-01

    Full Text Available We studied the effect of static magnetic fields on ethanol production by yeast Saccharomyces cerevisiae 424A (LNH-ST using sugar cane molasses during the fermentation in an enclosed bioreactor. Two static NdFeB magnets were attached to a cylindrical tube reactor with their opposite poles (north to south, creating 150 mT magnetic field inside the reactor. Comparable differences emerged between the results of these two experimental conditions. We found ethanol productivity to be 15% higher in the samples exposed to 150 mT magnetic field.

  19. Ammonia regulation of amino acid permeases in Saccharomyces cerevisiae.

    OpenAIRE

    Courchesne, W E; Magasanik, B

    1983-01-01

    The activities of the proline-specific permease (PUT4) and the general amino acid permease (GAP1) of Saccharomyces cerevisiae vary 70- to 140-fold in response to the nitrogen source of the growth medium. The PUT4 and GAP1 permease activities are regulated by control of synthesis and control of activity. These permeases are irreversibly inactivated by addition of ammonia or glutamine, lowering the activity to that found during steady-state growth on these nitrogen sources. Mutants altered in t...

  20. Expression of kinase-dependent glucose uptake in Saccharomyces cerevisiae.

    OpenAIRE

    Bisson, L. F.; Fraenkel, D. G.

    1984-01-01

    There are both low- and high-affinity mechanisms for uptake of glucose in Saccharomyces cerevisiae; high-affinity uptake somehow depends on the presence of hexose kinases (L. F. Bisson and D. G. Fraenkel, Proc. Natl. Acad. Sci. U.S.A. 80:1730-1734, 1983; L. F. Bisson and D. G. Fraenkel, J. Bacteriol. 155:995-1000, 1983). We report here on the effect of culture conditions on the level of high-affinity uptake. The high-affinity component was low during growth in high concentrations of glucose (...

  1. Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

    OpenAIRE

    Orlean, Peter

    2012-01-01

    The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of ?1,3- and ?1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of c...

  2. Cloning of the RNA2 gene of Saccharomyces cerevisiae.

    OpenAIRE

    Lee, M. G.; Young, R. A.; Beggs, J D

    1984-01-01

    The RNA2 gene of Saccharomyces cerevisiae, which has been implicated in splicing the transcripts of nuclear protein coding genes, has been cloned by complementation of the temperature-sensitive growth defect of an rna2-1 mutant strain. The cloned sequence also suppresses the accumulation of unspliced precursor transcripts of the actin gene in an rna2-1 mutant. The gene has been localised to a 3.2-kb DNA restriction fragment and the corresponding low abundance 2.8-kb transcript identified and ...

  3. Molecular Mechanism of Terbinafine Resistance in Saccharomyces cerevisiae

    OpenAIRE

    Leber, Regina; Fuchsbichler, Sandra; Klobu?níková, Vlasta; Schweighofer, Natascha; Pitters, Eva; Wohlfarter, Kathrin; Lederer, Mojca; Landl, Karina; Ruckenstuhl, Christoph; Hapala, Ivan; Turnowsky, Friederike

    2003-01-01

    Ten mutants of the yeast Saccharomyces cerevisiae resistant to the antimycotic terbinafine were isolated after chemical or UV mutagenesis. Molecular analysis of these mutants revealed single base pair exchanges in the ERG1 gene coding for squalene epoxidase, the target of terbinafine. The mutants did not show cross-resistance to any of the substrates of various pleiotropic drug resistance efflux pumps tested. The ERG1 mRNA levels in the mutants did not differ from those in the wild-type paren...

  4. Competing Crossover Pathways Act During Meiosis in Saccharomyces cerevisiae

    OpenAIRE

    Argueso, Juan Lucas; Wanat, Jennifer; Gemici, Zekeriyya; Alani, Eric

    2004-01-01

    In Saccharomyces cerevisiae the MSH4-MSH5, MLH1-MLH3, and MUS81-MMS4 complexes act to promote crossing over during meiosis. MSH4-MSH5, but not MUS81-MMS4, promotes crossovers that display interference. A role for MLH1-MLH3 in crossover control is less clear partly because mlh1? mutants retain crossover interference yet display a decrease in crossing over that is only slightly less severe than that seen in msh4? and msh5? mutants. We analyzed the effects of msh5?, mlh1?, and mms4? single, doub...

  5. Saccharomyces cerevisiae Vacuole in Zinc Storage and Intracellular Zinc Distribution? ‡

    OpenAIRE

    Simm, Claudia; Lahner, Brett; Salt, David; LeFurgey, Ann; Ingram, Peter; Yandell, Brian; Eide, David J

    2007-01-01

    Previous studies of the yeast Saccharomyces cerevisiae indicated that the vacuole is a major site of zinc storage in the cell. However, these studies did not address the absolute level of zinc that was stored in the vacuole nor did they examine the abundances of stored zinc in other compartments of the cell. In this report, we describe an analysis of the cellular distribution of zinc by use of both an organellar fractionation method and an electron probe X-ray microanalysis. With these method...

  6. accumulation and subcellular localisation of metal cations by saccharomyces cerevisiae

    OpenAIRE

    Blackwell, Kevin J.

    1998-01-01

    Uptake of Cd2+ ions m the presence or absence of glucose by a brewing strain of Saccharomyces cerevisiae was examined in unbuffered, buffered and pH controlled systems. Levels of Cd2+ taken up, and K+ release were influenced by the degree of pH control in each system. A time-dependent component of uptake was observed in the absence of glucose which was attributed to a degree of metabolic activity Subcellulai localisation studies determined that Cd2+ was predominantly bound by insoluble cellul...

  7. Saccharomyces cerevisiae RAD2 gene: isolation, subcloning, and partial characterization.

    OpenAIRE

    Naumovski, L; Friedberg, E. C.

    1984-01-01

    A plasmid (pNF2000) containing a 9.7-kilobase pair DNA insert that complements the UV sensitivity of rad2-1, rad2-2, and rad2-4 mutants of Saccharomyces cerevisiae has been isolated from a yeast genomic library. Genetic analysis of strains derived by transformation of rad2 mutants with an integrating plasmid containing a 9.3-kilobase pair fragment from pNF2000 shows that the fragment integrates exclusively at the chromosomal rad2 gene. We therefore conclude that this plasmid contains the RAD2...

  8. Oxalurate induction of multiple URA3 transcripts in Saccharomyces cerevisiae.

    OpenAIRE

    Buckholz, R G; Cooper, T G

    1983-01-01

    The URA3 gene from Saccharomyces cerevisiae is localized on a 1.1-kilobase (kb) DNA fragment. By using this fragment as a hybridization probe, we found that oxalurate, a gratuitous inducer of the allantoin degradative system, also serves to induce URA3 specific RNA. This response is restricted to oxalurate; other conditions which bring about high-level synthesis of the allantoin degradative enzymes did not produce the effect. Two classes of RNA (1.0 and 1.5 kb) were found to be oxalurate indu...

  9. Saccharomyces cerevisiae: a potential biosorbent for biosorption of uranium.

    OpenAIRE

    PROF. RAJESH DHANKHAR; ANJU HOODA; RADHA SOLANKI; POONAM AHLAWAT SAINGER

    2011-01-01

    This paper projects the potential of Saccharomyces cerevisiae in biosorbing U (VI) ion on nonliving biomass of specie in batch system with respect to pH, Biosorbent dose, Initial metal concentration, Contact time and Particle size. From the batch studies, it was found that the fungal biomass exhibited the optimum Uranium uptake at pH 5 and 100 ?m particle size, adsorbent dose of 10g/L and initial metal concentration of 100mg/L. Maximum uptake was observed after the Contact time of 75 minutes....

  10. Saccharomyces cerevisiae Biyokütlesi ile Remazol Navy Blue Boyar Maddesinin Biyosorpsiyonu

    OpenAIRE

    KORHAN, Hamdullah; HAL?PÇ?, Hatice Nur; KERTMEN, Metin; DI?RAK, Metin

    2012-01-01

    Özet: Dünyada giderek artan nüfusla birlikte geli?en teknoloji ve h?zl? sanayile?me, çok büyük ve çözülmesi giderek zorla?an bir problemi, çevre kirlili?ini de beraberinde getirmi?tir. Bugün bu kirlilik do?an?n dengesini bozar duruma gelmi? ve insan ya?am?n? tehdit eden boyutlara ula?m??t?r. Yeryüzünün büyük bir bölümünü olu?turan su ortam?, geçmi?ten günümüze hava ve topraktan çok daha fazla kirlili?e maruz kalm??t?r. Bu çal??mada Saccharomyces cerevisiae ile Remazol Navy Blue (RNB)'nun adso...

  11. Saccharomyces cerevisiae Biyokütlesi ?le Remazol Turkuaz Blue Boyar Maddesinin Biyosorpsiyonu

    OpenAIRE

    HAL?PÇ?, Hatice Nur; KORHAN, Hamdullah; DI?RAK, Metin; KERTMEN, Metin

    2012-01-01

    Özet: Çe?itli sanayi kurulu?lar?n?n neden oldu?u boyar madde kirlilikleri, çevreyi olumsuz yönde etkilemekte ve özellikle insan sa?l???n? tehdit etmektedir. Günümüzde bu tür çevresel problemler önemli bir yer te?kil ederken, bu amaçla birçok çal??malar yap?lmaktad?r. Bu çal??mada Saccharomyces cerevisiae ile Remazol Turkuaz Blue (RTB)'nun adsorpsiyon tekni?i ile giderilmesi ara?t?r?lm??t?r. Bu amaçla, boyar madde konsantrasyonu, pH ve s?cakl???n adsorpsiyon üzerine etkisi incelenmi?tir. Çal??...

  12. A Role for the Saccharomyces cerevisiae Regulation of Ace2 and Polarized Morphogenesis Signaling Network in Cell Integrity

    OpenAIRE

    Kurischko, Cornelia; Weiss, Gretchen; Ottey, Michelle; Luca, Francis C.

    2005-01-01

    Saccharomyces cerevisiae RAM is a conserved signaling network that regulates maintenance of polarized growth and daughter-cell-specific transcription, the latter of which is critical for septum degradation. Consequently, cells defective in RAM function (designated ram?) are round in morphology, form feeble mating projections, and fail to separate following cytokinesis. It was recently demonstrated that RAM genes are essential in strains containing functional SSD1 (SSD1-v), which encodes a pro...

  13. Regulation of the Premiddle and Middle Phases of Expression of the NDT80 Gene during Sporulation of Saccharomyces cerevisiae

    OpenAIRE

    Pak, Julia; Segall, Jacqueline

    2002-01-01

    The NDT80 gene of Saccharomyces cerevisiae, which encodes a global activator of transcription of middle sporulation-specific genes, is first expressed after the activation of early meiotic genes but prior to activation of middle sporulation-specific genes. Both upstream repression sequence 1 (URS1) and mid-sporulation element (MSE) sites are present in the promoter region of the NDT80 gene; these elements have been shown previously to contribute to the regulation of expression of early and mi...

  14. Saccharomyces Cerevisiae Cho2 Mutants Are Deficient in Phospholipid Methylation and Cross-Pathway Regulation of Inositol Synthesis

    OpenAIRE

    Summers, E. F.; Letts, V.A.; McGraw, P.; Henry, S A

    1988-01-01

    Five allelic Saccharomyces cerevisiae mutants deficient in the methylation of phosphatidylethanolamine (PE) have been isolated, using two different screening techniques. Biochemical analysis suggested that these mutants define a locus, designated CHO2, that may encode a methyltransferase. Membranes of cho2 mutant cells grown in defined medium contain approximately 10% phosphatidylcholine (PC) and 40-50% PE as compared to wild-type levels of 40-45% PC and 15-20% PE. In spite of this greatly al...

  15. Mutations that cause threonine sensitivity identify catalytic and regulatory regions of the aspartate kinase of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Arévalo-Rodríguez, M; Calderón, I L; Holmberg, S

    1999-01-01

    The HOM3 gene of Saccharomyces cerevisiae encodes aspartate kinase, which catalyses the first step in the branched pathway leading to the synthesis of threonine and methionine from aspartate. Regulation of the carbon flow into this pathway takes place mainly by feedback inhibition of this enzyme by threonine. We have isolated and characterized three HOM3 mutants that show growth inhibition by threonine due to a severe, threonine-induced reduction of the carbon flow into the aspartate pathway, le...

  16. Flavin Mononucleotide-Based Fluorescent Protein as an Oxygen-Independent Reporter in Candida albicans and Saccharomyces cerevisiae? †

    OpenAIRE

    Tielker, D.; Eichhof, I.; Jaeger, K.-E.; Ernst, J F

    2009-01-01

    Hypoxia is encountered frequently by pathogenic and apathogenic fungi. A codon-adapted gene encoding flavin mononucleotide-based fluorescent protein (CaFbFP) was expressed in Candida albicans and Saccharomyces cerevisiae. Both species produced CaFbFP and fluoresced even during hypoxia, suggesting that oxygen-independent CaFbFP is a useful, novel tool for monitoring hypoxic gene expression in fungi.

  17. Effects of Various Physiological Stresses on Transcription of the SUC2Gene in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Türkel, Sezai

    2000-01-01

    Physiological conditions in the growth habitat of yeast cells dramatically changes the gene expression pattern. In this study, it was shown that transcription of the SUC2gene, which encodes the cytoplasmic and secreted enzyme invertase, is modulated according to the environmental conditions in the yeast Saccharomyces cerevisiae. Hyperosmotic stress and oxidative stress repressed the transcription of the SUC2gene up to 50%. However, preconditioning of the yeast cells prevented the negativ...

  18. Novel Role for the C Terminus of Saccharomyces cerevisiae Rev1 in Mediating Protein-Protein Interactions?

    OpenAIRE

    D'Souza, Sanjay; Walker, Graham C.

    2006-01-01

    The Saccharomyces cerevisiae REV3/7-encoded polymerase ? and Rev1 are central to the replicative bypass of DNA lesions, a process called translesion synthesis (TLS). While yeast polymerase ? extends from distorted DNA structures, Rev1 predominantly incorporates C residues from across a template G and a variety of DNA lesions. Intriguingly, Rev1 catalytic activity does not appear to be required for TLS. Instead, yeast Rev1 is thought to participate in TLS by facilitating protein-protein intera...

  19. Control of 5?,5?-Dinucleoside Triphosphate Catabolism by APH1, a Saccharomyces cerevisiae Analog of Human FHIT

    OpenAIRE

    Chen, Josiane; Brevet, Annie; Blanquet, Sylvain; Plateau, Pierre

    1998-01-01

    The putative human tumor suppressor gene FHIT (fragile histidine triad) (M. Ohta et al., Cell 84:587–597, 1996) encodes a protein behaving in vitro as a dinucleoside 5?,5???-P1,P3-triphosphate (Ap3A) hydrolase. In this report, we show that the Saccharomyces cerevisiae APH1 gene product, which resembles human Fhit protein, also hydrolyzes dinucleoside 5?,5?-polyphosphates, with Ap3A being the preferred substrate. Accordingly, disruption of the APH1 gene produced viable S. cerevisiae cells cont...

  20. Control of 5',5'-dinucleoside triphosphate catabolism by APH1, a Saccharomyces cerevisiae analog of human FHIT.

    Science.gov (United States)

    Chen, J; Brevet, A; Blanquet, S; Plateau, P

    1998-05-01

    The putative human tumor suppressor gene FHIT (fragile histidine triad) (M. Ohta et al., Cell 84:587-597, 1996) encodes a protein behaving in vitro as a dinucleoside 5',5"'-P1,P3-triphosphate (Ap3A) hydrolase. In this report, we show that the Saccharomyces cerevisiae APH1 gene product, which resembles human Fhit protein, also hydrolyzes dinucleoside 5',5'-polyphosphates, with Ap3A being the preferred substrate. Accordingly, disruption of the APH1 gene produced viable S. cerevisiae cells containing reduced Ap3A-hydrolyzing activity and a 30-fold-elevated Ap3N concentration. PMID:9573184

  1. Identification of a developmentally regulated septin and involvement of the septins in spore formation in Saccharomyces cerevisiae

    OpenAIRE

    1996-01-01

    The Saccharomyces cerevisiae CDC3, CDC10, CDC11, and CDC12 genes encode a family of related proteins, the septins, which are involved in cell division and the organization of the cell surface during vegetative growth. A search for additional S. cerevisiae septin genes using the polymerase chain reaction identified SPR3, a gene that had been identified previously on the basis of its sporulation-specific expression. The predicted SPR3 product shows 25-40% identity in amino acid sequence to the ...

  2. Acquisition of the ability to assimilate mannitol by Saccharomyces cerevisiae through dysfunction of the general corepressor Tup1-Cyc8.

    Science.gov (United States)

    Chujo, Moeko; Yoshida, Shiori; Ota, Anri; Murata, Kousaku; Kawai, Shigeyuki

    2015-01-01

    Saccharomyces cerevisiae normally cannot assimilate mannitol, a promising brown macroalgal carbon source for bioethanol production. The molecular basis of this inability remains unknown. We found that cells capable of assimilating mannitol arose spontaneously from wild-type S. cerevisiae during prolonged culture in mannitol-containing medium. Based on microarray data, complementation analysis, and cell growth data, we demonstrated that acquisition of mannitol-assimilating ability was due to spontaneous mutations in the genes encoding Tup1 or Cyc8, which constitute a general corepressor complex that regulates many kinds of genes. We also showed that an S. cerevisiae strain carrying a mutant allele of CYC8 exhibited superior salt tolerance relative to other ethanologenic microorganisms; this characteristic would be highly beneficial for the production of bioethanol from marine biomass. Thus, we succeeded in conferring the ability to assimilate mannitol on S. cerevisiae through dysfunction of Tup1-Cyc8, facilitating production of ethanol from mannitol. PMID:25304510

  3. Introducing a New Breed of Wine Yeast: Interspecific Hybridisation between a Commercial Saccharomyces cerevisiae Wine Yeast and Saccharomyces mikatae

    OpenAIRE

    Bellon, Jennifer R.; Schmid, Frank; Capone, Dimitra L.; Dunn, Barbara L.; Chambers, Paul J.

    2013-01-01

    Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentatio...

  4. Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains

    Scientific Electronic Library Online (English)

    Míriam Cristina Sakuragui, Matuo; Irene Satiko, Kikuchi; Terezinha de Jesus Andreoli, Pinto.

    2010-09-01

    Full Text Available Linhagens de Saccharomyces cerevisiae tem sido amplamente empregadas em testes de mutagenicidade devido à presença de um sistema citocromo P-450 capaz de metabolizar substâncias pró-mutagênicas à sua forma ativa. Devido à grande variedade de linhagens de S. cerevisiae com diferentes capacidades de p [...] rodução de citocromo P-450, torna-se necessária a seleção de cepas, bem como a definição das condições ideais de cultivo. Neste trabalho, foram comparados os níveis de citocromo P-450 em quatro diferentes linhagens de S. cerevisiae e avaliadas as condições de cultivo necessárias para obtenção de altas concentrações deste sistema enzimático. O maior nível enzimático foi encontrado na linhagem NCYC 240 em presença de 20 % de glicose (p/v). A adição de etanol ao meio de cultura também produziu um aumento na síntese de citocromo P-450. Estes resultados indicam que as condições de cultivo devem ser específicas e bem definidas para a linhagem selecionada, garantindo assim elevados níveis de citocromo P-450 e, conseqüentemente, a confiabilidade nos testes de mutagenicidade. Abstract in english Saccharomyces cerevisiae has been widely used in mutagenicity tests due to the presence of a cytochrome P-450 system, capable of metabolizing promutagens to active mutagens. There are a large number of S. cerevisiae strains with varying abilities to produce cytochrome P-450. However, strain selectio [...] n and ideal cultivation conditions are not well defined. We compared cytochrome P-450 levels in four different S. cerevisiae strains and evaluated the cultivation conditions necessary to obtain the highest levels. The amount of cytochrome P-450 produced by each strain varied, as did the incubation time needed to reach the maximum level. The highest cytochrome P-450 concentrations were found in media containing fermentable sugars. The NCYC 240 strain produced the highest level of cytochrome P-450 when grown in the presence of 20 % (w/v) glucose. The addition of ethanol to the media also increased cytochrome P-450 synthesis in this strain. These results indicate cultivation conditions must be specific and well-established for the strain selected in order to assure high cytochrome P-450 levels and reliable mutagenicity results.

  5. Beta-glucana from Saccharomyces cerevisiae: constitution, bioactivity and obtaining / Beta-glucana de Saccharomyces cerevisiae: constituição, bioatividade e obtenção

    Directory of Open Access Journals (Sweden)

    Raul Jorge Hernan Castro-Gómez

    2008-08-01

    Full Text Available b-glucans are polysaccharides that constitute the structure of the cell wall of yeast, fungi and some cereals, which differs each other by the linkages between glucose units. An important source of these polymers is the Saccharomyces cerevisiae cell wall, which is a yeast widely used in industrial processes of fermentation. The b-glucan is considered to be a modifier of biological response due to its immunomodulator potential. When it is recognized by specific cellular receptors, have the ability to enhance the host’s immune response. Other beneficial effects such as anticarcinogenic, antimutagenic, hypocholesterolemic and blood sugar reduction have also been related to the b-glucan. The aim of this literature review was expand scientific knowledge about the constitution and bioactivity of b-glucan, including its recognition by the immune system, as well as its obtaining from S. cerevisiae cell wall.b-glucanas são polissacarídeos constituintes estruturais da parede celular de leveduras, fungos e alguns cereais, que se diferenciam pelo tipo de ligação presente entre as unidades de glicose. Uma importante fonte destes polissacarídeos é a parede celular de Saccharomyces cerevisiae, uma levedura amplamente empregada em processos industriais de fermentação. A b-glucana é considerada um modificador da resposta biológica devido ao seu potencial imunomodulador, pois ao ser reconhecida por receptores celulares específicos tem habilidade de realçar a resposta imune do hospedeiro. Outros efeitos benéficos como anticarcinogênico, antimutagênico, hipocolesterolêmico e hipoglicêmico também têm sido relacionados à b-glucana Esta revisão de literatura teve por objetivo agregar conhecimentos científicos sobre a constituição e bioatividade da b glucana, incluindo seu reconhecimento pelo sistema imune, bem como, a obtenção a partir da parede celular de S. cerevisiae.

  6. Acquisition of tolerance against oxidative damage in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Eleutherio Elis CA

    2001-07-01

    Full Text Available Abstract Background Living cells constantly sense and adapt to redox shifts by the induction of genes whose products act to maintain the cellular redox environment. In the eukaryote Saccharomyces cerevisiae, while stationary cells possess a degree of constitutive resistance towards oxidants, treatment of exponential phase cultures with sub-lethal stresses can lead to the transient induction of protection against subsequent lethal oxidant conditions. The sensors of oxidative stress and the corresponding transcription factors that activate gene expression under these conditions have not yet been completely identified. Results We report the role of SOD1, SOD2 and TPS1 genes (which encode the cytoplasmic Cu/Zn-superoxide dismutase, the mitochondrial Mn-isoform and trehalose-6-phosphate synthase, respectively in the development of resistance to oxidative stress. In all experimental conditions, the cultures were divided into two parts, one was immediately submitted to severe stress (namely: exposure to H2O2, heat shock or ethanol stress while the other was initially adapted to 40°C for 60 min. The deficiency in trehalose synthesis did not impair the acquisition of tolerance to H2O2, but this disaccharide played an essential role in tolerance against heat and ethanol stresses. We also verified that the presence of only one Sodp isoform was sufficient to improve cellular resistance to 5 mM H2O2. On the other hand, while the lack of Sod2p caused high cell sensitivity to ethanol and heat shock, the absence of Sod1p seemed to be beneficial to the process of acquisition of tolerance to these adverse conditions. The increase in oxidation-dependent fluorescence of crude extracts of sod1 mutant cells upon incubation at 40°C was approximately 2-fold higher than in sod2 and control strain extracts. Furthermore, in Western blots, we observed that sod mutants showed a different pattern of Hsp104p and Hsp26p expression also different from that in their control strain. Conclusions Trehalose seemed not to be essential in the acquisition of tolerance to H2O2 stress, but its absence was strongly felt under water stress conditions such as heat and alcoholic stresses. On the other hand, Sod1p could be involved in the control of ROS production; these reactive molecules could signal the induction of genes implicated within cell tolerance to heat and ethanol. The effects of this deletion needs further investigation.

  7. On the fermentative behavior of auxotrophic strains of Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Lucia, Paciello; Jesus, Zueco; Carmine, Landi.

    2014-09-15

    Full Text Available 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 recen [...] tly 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. cerevisiae BY4741. Results The results indicate that the fermentative capacity of strains grown in 2% glucose was similar in all the strains tested. However, in 15% initial glucose, the auxotrophic strains exhibited a more than doubled ethanol yield on biomass (10 g g- 1dw) compared to the prototrophic strains (less than 5 g g- 1dw). Other tests have also evidenced that in medium depletion conditions, ethanol production continues after growth arrest. Conclusions The results highlight the capacity of auxotrophic yeast strains to produce ethanol per mass unit, in a higher amount with respect to the prototrophic ones. This leads to potential applications for auxotrophic strains of S. cerevisiae in the production of ethanol in both homogeneous and heterogeneous phases (immobilized systems). The higher ethanol yield on biomass would be advantageous in immobilized cell systems, as a reduced yeast biomass could greatly reduce the mass transfer limitations through the immobilization matrix.

  8. A vaccine grade of yeast Saccharomyces cerevisiae expressing mammalian myostatin

    Directory of Open Access Journals (Sweden)

    Zhang Tingting

    2012-12-01

    Full Text Available Abstract Background Yeast Saccharomyces cerevisiae is a widely-used system for protein expression. We previously showed that heat-killed whole recombinant yeast vaccine expressing mammalian myostatin can modulate myostatin function in mice, resulting in increase of body weight and muscle composition in these animals. Foreign DNA introduced into yeast cells can be lost soon unless cells are continuously cultured in selection media, which usually contain antibiotics. For cost and safety concerns, it is essential to optimize conditions to produce quality food and pharmaceutical products. Results We developed a simple but effective method to engineer a yeast strain stably expressing mammalian myostatin. This method utilized high-copy-number integration of myostatin gene into the ribosomal DNA of Saccharomyces cerevisiae. In the final step, antibiotic selection marker was removed using the Cre-LoxP system to minimize any possible side-effects for animals. The resulting yeast strain can be maintained in rich culture media and stably express mammalian myostatin for two years. Oral administration of the recombinant yeast was able to induce immune response to myostatin and modulated the body weight of mice. Conclusions Establishment of such yeast strain is a step further toward transformation of yeast cells into edible vaccine to improve meat production in farm animals and treat human muscle-wasting diseases in the future.

  9. Metabolic Engineering of Saccharomyces cerevisiae for Conversion of d-Glucose to Xylitol and Other Five-Carbon Sugars and Sugar Alcohols?

    OpenAIRE

    Toivari, Mervi H.; Ruohonen, Laura; Miasnikov, Andrei N.; Richard, Peter; Penttilä, Merja

    2007-01-01

    Recombinant Saccharomyces cerevisiae strains that produce the sugar alcohols xylitol and ribitol and the pentose sugar d-ribose from d-glucose in a single fermentation step are described. A transketolase-deficient S. cerevisiae strain accumulated d-xylulose 5-phosphate intracellularly and released ribitol and pentose sugars (d-ribose, d-ribulose, and d-xylulose) into the growth medium. Expression of the xylitol dehydrogenase-encoding gene XYL2 of Pichia stipitis in the transketolase-deficient...

  10. The cauliflower mosaic virus open reading frame VII product can be expressed in Saccharomyces cerevisiae but is not detected in infected plants.

    OpenAIRE

    Wurch, T; Kirchherr, D; Mesnard, J. M.; Lebeurier, G

    1990-01-01

    Antiserum was prepared against a synthetic peptide corresponding to the N-terminal 20 amino acids of the protein encoded by cauliflower mosaic virus (CaMV) open reading frame VII (ORF VII). This antiserum was used to detect the expression of CaMV ORF VII either in Saccharomyces cerevisiae transformed by an expression vector containing CaMV ORF VII or in CaMV-infected plants. Only in S. cerevisiae has a 14-kilodalton protein been detected.

  11. Disruption of the Saccharomyces cerevisiae homologue to the murine fatty acid transport protein impairs uptake and growth on long-chain fatty acids

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; DiRusso, C C; Elberger, A; Knudsen, J; Black, P N

    1997-01-01

    The yeast Saccharomyces cerevisiae is able to utilize exogenous fatty acids for a variety of cellular processes including beta-oxidation, phospholipid biosynthesis, and protein modification. The molecular mechanisms that govern the uptake of these compounds in S. cerevisiae have not been described. We report the characterization of FAT1, a gene that encodes a putative membrane-bound long-chain fatty acid transport protein (Fat1p). Fat1p contains 623 amino acid residues that are 33% identical and...

  12. Engineering cellular redox balance in Saccharomyces cerevisiae for improved production of L-lactic acid.

    Science.gov (United States)

    Lee, Ju Young; Kang, Chang Duk; Lee, Seung Hyun; Park, Young Kyoung; Cho, Kwang Myung

    2015-04-01

    Owing to the growing market for the biodegradable and renewable polymer, polylactic acid, world demand for lactic acid is rapidly increasing. However, the very high concentrations desired for industrial production of the free lactic acid create toxicity and low pH concerns for manufacturers. Saccharomyces cerevisiae is the most well characterized eukaryote, a preferred microbial cell factory for the largest industrial biotechnology product (bioethanol), and a robust, commercially compatible workhorse to be exploited for the production of diverse chemicals. S. cerevisiae has also been explored as a host for lactic acid production because of its high acid tolerance. Here, we constructed an L-lactic acid-overproducing S. cerevisiae by redirecting cellular metabolic fluxes to the production of L-lactic acid. To this end, we deleted the S. cerevisiae genes encoding pyruvate decarboxylase 1 (PDC1), L-lactate cytochrome-c oxidoreductase (CYB2), and glycerol-3-phosphate dehydrogenase (GPD1), replacing them with a heterologous L-lactate dehydrogenase (LDH) gene. Two new target genes encoding isoenzymes of the external NADH dehydrogenase (NDE1 and NDE2), were also deleted from the genome to re-engineer the intracellular redox balance. The resulting strain was found to produce L-lactic acid more efficiently (32.6% increase in final L-lactic acid titer). When tested in a bioreactor in fed-batch mode, this engineered strain produced 117?g/L of L-lactic acid under low pH conditions. This result demonstrates that the redox balance engineering should be coupled with the metabolic engineering in the construction of L-lactic acid-overproducing S. cerevisiae. PMID:25363674

  13. Genetic immobilization of cellulase on the cell surface of Saccharomyces cerevisiae.

    Science.gov (United States)

    Murai, T; Ueda, M; Atomi, H; Shibasaki, Y; Kamasawa, N; Osumi, M; Kawaguchi, T; Arai, M; Tanaka, A

    1997-10-01

    We tried genetically to immobilize cellulase protein on the cell surface of the yeast Saccharomyces cerevisiae in its active form. A cDNA encoding FI-carboxymethylcellulase (CMCase) of the fungus Aspergillus aculeatus, with its secretion signal peptide, was fused with the gene encoding the C-terminal half (320 amino acid residues from the C terminus) of yeast alpha-agglutinin a protein involved in mating and covalently anchored to the cell wall. The plasmid constructed containing this fusion gene was introduced into S. cerevisiae and expressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter from S. cerevisiae. The CMCase activity was detected in the cell pellet fraction. The CMCase protein was solubilized from the cell wall fraction by glucanase treatment but not by sodium dodecyl sulphate treatment, indicating the covalent binding of the fusion protein to the cell wall. The appearance of the fused protein on the cell surface was further confirmed by immunofluorescence microscopy and immunoelectron microscopy. These results proved that the CMCase was anchored on the cell wall in its active form. PMID:9390459

  14. The postmitotic Saccharomyces cerevisiae after spaceflight showed higher viability

    Science.gov (United States)

    Yi, Zong-Chun; Li, Xiao-Fei; Wang, Yan; Wang, Jie; Sun, Yan; Zhuang, Feng-Yuan

    2011-06-01

    The budding yeast Saccharomyces cerevisiae has been proposed as an ideal model organism for clarifying the biological effects caused by spaceflight conditions. The postmitotic S. cerevisiae cells onboard Practice eight recoverable satellite were subjected to spaceflight for 15 days. After recovery, the viability, the glycogen content, the activities of carbohydrate metabolism enzymes, the DNA content and the lipid peroxidation level in yeast cells were analyzed. The viability of the postmitotic yeast cells after spaceflight showed a three-fold increase as compared with that of the ground control cells. Compared to the ground control cells, the lipid peroxidation level in the spaceflight yeast cells markedly decreased. The spaceflight yeast cells also showed an increase in G2/M cell population and a decrease in Sub-G1 cell population. The glycogen content and the activities of hexokinase and succinate dehydrogenase significantly decreased in the yeast cells after spaceflight. In contrast, the activity of malate dehydrogenase showed an obvious increase after spaceflight. These results suggested that microgravity or spaceflight could promote the survival of postmitotic S. cerevisiae cells through regulating carbohydrate metabolism, ROS level and cell cycle progression.

  15. Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae. S. cerevisiae suspensions of 1.5x108 clls/ml were exposed to single and fractionated doses of gamma irradiation, i.e. 0; 0.30; 0.60; 0.90; and 1.20 kGy in aerobic condition at dose rate of 1.63 kGy/hour. The fractionated doses were given with time interval of 15, 30 and 45 minutes. The fermentation was held at 300C for 40 hours. It is seen that an increase of alcohol production was obtained when cells were irradiated at 0.60 kGy, although the result has no significant difference statistically with control. At the dose of 1.20 kGy the alcohol fermentation ability of S. cerevisiae decreased drastically as compared to control. Irradiation using single or fractionated doses with time interval of 15-45 minutes did not influence the alcohol production. Comparing the time interval of 45 minutes at 0.60 kGy and at 1.20 kGy, it appeared that the yield of alcohol was different. (author). 17 refs.; 4 figs

  16. Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vemuri, Goutham; Eiteman, M.A

    2007-01-01

    Respiratory metabolism plays an important role in energy production in the form of ATP in all aerobically growing cells. However, a limitation in respiratory capacity results in overflow metabolism, leading to the formation of byproducts, a phenomenon known as ‘‘overflow metabolism’’ or ‘‘the Crabtree effect.’’ The yeast Saccharomyces cerevisiae has served as an important model organism for studying the Crabtree effect. When subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from purely respiratory to mixed respiratory and fermentative. It is well known that glucose repression of respiratory pathways occurs at high glycolytic fluxes, resulting in a decrease in respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree effect is due to limited respiratory capacity or is caused by glucose-mediated repression of respiration. When respiration inS. cerevisiae was increased by introducing a heterologous alternative oxidase, we observed reduced aerobic ethanol formation. In contrast, increasing nonrespiratory NADH oxidation by overexpression of a water-forming NADH oxidase reduced aerobic glycerol formation. The metabolic response to elevated alternative oxidase occurred predominantly in the mitochondria, whereas NADH oxidase affected genes that catalyze cytosolic reactions. Moreover, NADH oxidase restored the deficiency of cytosolic NADH dehydrogenases in S. cerevisiae. These results indicate that NADH oxidase localizes in the cytosol, whereas alternative oxidase is directed to the mitochondria.

  17. Osmo-, thermo- and ethanol- tolerances of Saccharomyces cerevisiae S1

    Scientific Electronic Library Online (English)

    Sandrasegarampillai, Balakumar; Vasanthy, Arasaratnam.

    2012-03-01

    Full Text Available Saccharomyces cerevisiae S1, which is a locally isolated and improved strain showed viability at 40, 45 and 50ºC and produced ethanol at 40, 43 and 45ºC. When the cells were given heat shock at 45ºC for 30min and grown at 40ºC, 100% viability was observed for 60h, and addition of 200gl-1 ethanol has [...] led to complete cell death at 30h. Heat shock given at 45ºC (for 30min) has improved the tolerance to temperature induced ethanol shock leading to 37% viability at 30h. when the cells were subjected to ethanol (200gl-1 for 30 min) and osmotic shock (sorbitol 300gl-1), trehalose contents in the cells were increased. The heat shocked cells showed better viability in presence of added ethanol. Soy flour supplementation has improved the viability of S. cerevisiae S1 to 80% in presence of 100gl-1 added ethanol and to 60% in presence of 300gl-1 sorbitol. In presence of sorbitol (200gl-1) and ethanol (50gl-1) at 40ºC, 46% viability was retained by S. cerevisiae S1 at 48h and it was improved to 80% by soy flour supplementation.

  18. Osmo-, thermo- and ethanol- tolerances of Saccharomyces cerevisiae S1

    Directory of Open Access Journals (Sweden)

    Sandrasegarampillai Balakumar

    2012-03-01

    Full Text Available Saccharomyces cerevisiae S1, which is a locally isolated and improved strain showed viability at 40, 45 and 50ºC and produced ethanol at 40, 43 and 45ºC. When the cells were given heat shock at 45ºC for 30min and grown at 40ºC, 100% viability was observed for 60h, and addition of 200gl-1 ethanol has led to complete cell death at 30h. Heat shock given at 45ºC (for 30min has improved the tolerance to temperature induced ethanol shock leading to 37% viability at 30h. when the cells were subjected to ethanol (200gl-1 for 30 min and osmotic shock (sorbitol 300gl-1, trehalose contents in the cells were increased. The heat shocked cells showed better viability in presence of added ethanol. Soy flour supplementation has improved the viability of S. cerevisiae S1 to 80% in presence of 100gl-1 added ethanol and to 60% in presence of 300gl-1 sorbitol. In presence of sorbitol (200gl-1 and ethanol (50gl-1 at 40ºC, 46% viability was retained by S. cerevisiae S1 at 48h and it was improved to 80% by soy flour supplementation.

  19. Uranium removal from acidic aqueous solutions by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa

    International Nuclear Information System (INIS)

    The sorption of uranium from acidic aqueous solutions (pH 4.5, Cinit = 10 to 1000 mg U/L) by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa was investigated using a batch technique. The U-sorption onto Saccharomyces cerevisiae and Debaryomyces hansenii followed a Langmuir, while that onto Kluyveromyces marxianus and Candida colliculosa a Freundlich isotherm. The results demonstrated that all investigated biomasses could effectively remove uranium from acidic aqueous solutions. From all sorbents, Saccharomyces cerevisiae appeared to be the most effective with a maximum sorption capacity of 127.7 mg U/g dry biomass. (author)

  20. Histone H1 of Saccharomyces cerevisiae Inhibits Transcriptional Silencing

    OpenAIRE

    Veron, Marie; Zou, Yanfei; Yu, Qun; Bi, Xin; Selmi, Abdelkader; Gilson, Eric; Defossez, Pierre-Antoine

    2006-01-01

    Eukaryotic genomes contain euchromatic regions, which are transcriptionally active, and heterochromatic regions, which are repressed. These domains are separated by “barrier elements”: DNA sequences that protect euchromatic regions from encroachment by neighboring heterochromatin. To identify proteins that play a role in the function of barrier elements we have carried out a screen in S. cerevisiae. We recovered the gene HHO1, which encodes the yeast ortholog of histone H1, as a high-copy mod...

  1. Heterologous production of non-ribosomal peptide LLD-ACV in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Siewers, Verena; Chen, Xiao

    2009-01-01

    Non-ribosomal peptides (NRPs) are a diverse family of secondary metabolites with a broad range of biological activities. We started to develop an eukaryotic microbial platform based on the yeast Saccharomyces cerevisiae for heterologous production of NRPs using ?-(l-?-aminoadipyl)–l-cysteinyl–d-valine (ACV) as a model NRP. The Penicillium chrysogenum gene pcbAB encoding ACV synthetase was expressed in S. cerevisiae from a high-copy plasmid together with phosphopantetheinyl transferase (PPTase) encoding genes from Aspergillus nidulans, P. chrysogenum and Bacillus subtilis, and in all the three cases production of ACV was observed. To improve ACV synthesis, several factors were investigated. Codon optimization of the 5? end of pcbAB did not significantly increase ACV production. However, a 30-fold enhancement was achieved by lowering the cultivation temperature from 30 to 20 °C. When ACVS and PPTase encoding genes were integrated into the yeast genome, a 6-fold decrease in ACV production was observed indicatingthat gene copy number was one of the rate-limiting factors for ACV production in yeast.

  2. Impact of systems biology on metabolic engineering of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Nielsen, Jens; Jewett, Michael Christopher

    2008-01-01

    Industrial biotechnology is a rapidly growing field. With the increasing shift towards a bio-based economy, there is rising demand for developing efficient cell factories that can produce fuels, chemicals, pharmaceuticals, materials, nutraceuticals, and even food ingredients. The yeast Saccharomyces cerevisiae is extremely well suited for this objective. As one of the most intensely studied eukaryotic model organisms, a rich density of knowledge detailing its genetics, biochemistry, physiology, and large-scale fermentation performance can be capitalized upon to enable a substantial increase in the industrial application of this yeast. Developments in genomics and high-throughput systems biology tools are enhancing one's ability to rapidly characterize cellular behaviour, which is valuable in the field of metabolic engineering where strain characterization is often the bottleneck in strain development programmes. Here, the impact of systems biology on metabolic engineering is reviewed and perspectives on the role of systems biology in the design of cell factories are given.

  3. Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress

    Scientific Electronic Library Online (English)

    Rafael A. de, Sá; Frederico A.V. de, Castro; Elis C.A., Eleutherio; Raquel M. de, Souza; Joaquim F.M. da, Silva; Marcos D., Pereira.

    2013-09-01

    Full Text Available Propolis is a natural product widely used for humans. Due to its complex composition, a number of applications (antimicrobial, antiinflammatory, anesthetic, cytostatic and antioxidant) have been attributed to this substance. Using Saccharomyces cerevisiae as a eukaryotic model we investigated the me [...] chanisms underlying the antioxidant effect of propolis from Guarapari against oxidative stress. Submitting a wild type (BY4741) and antioxidant deficient strains (ctt1?, sod1?, gsh1?, gtt1? and gtt2?) either to 15 mM menadione or to 2 mM hydrogen peroxide during 60 min, we observed that all strains, except the mutant sod1?, acquired tolerance when previously treated with 25 µg/mL of alcoholic propolis extract. Such a treatment reduced the levels of ROS generation and of lipid peroxidation, after oxidative stress. The increase in Cu/Zn-Sod activity by propolis suggests that the protection might be acting synergistically with Cu/Zn-Sod.

  4. Saccharomyces cerevisiae: a potential biosorbent for biosorption of uranium.

    Directory of Open Access Journals (Sweden)

    PROF. RAJESH DHANKHAR

    2011-06-01

    Full Text Available This paper projects the potential of Saccharomyces cerevisiae in biosorbing U (VI ion on nonliving biomass of specie in batch system with respect to pH, Biosorbent dose, Initial metal concentration, Contact time and Particle size. From the batch studies, it was found that the fungal biomass exhibited the optimum Uranium uptake at pH 5 and 100 ?m particle size, adsorbent dose of 10g/L and initial metal concentration of 100mg/L. Maximum uptake was observed after the Contact time of 75 minutes. Sorption isotherms were interpreted interms of Langmuir and Freundlich models. Equilibrium data fitted well to Langmuir model and Uptake kinetic followed pseudo-second order model. Base treatment was found to enhance the metal removal ability of untreated biomass. The mechanism of process was gained by FTIR and SEM. IR spectra analysis revealed that Carbonyl and amino groups have played important role in U (VI biosorption.

  5. Structural properties of Saccharomyces cerevisiae protein complex network

    CERN Document Server

    Ramezanpour, A; Karimipour, V

    2003-01-01

    Recent studies indicate that protein complexes rather than individual proteins are the functional units of the cell. A first step in the understanding of integration and coordination of these cellular functions is a comprehensive study of the structural features of the network of connections between these complexes. We use the recently obtained data based on tandem-affinity purification (TAP) and mass spectrometry, to study the structural features of the yeast Saccharomyces cerevisiae protein complex network. We find striking similarities and differences between the structural properties of the networks of proteins and protein complexes. The network of complexes is still a small world network with scale free distributions for many of its properties (e.g. connectivity and size of complexes). However in contrast to the protein network, we find no correlations between the degrees of neighbouring complexes. There is also no correlation between the size of neighbouring complexes. Finally we propose a simple evolut...

  6. Uranium adsorption by dry and wet immobilized Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Immobilized Saccharomyces cerevisiae (ISC) was prepared by the sodium alginate-gelatin embedding method after dry cells had been cross-linked by formaldehyde. Adsorption of uranium(VI) by incompletely and completely dry ISC was studied. The results indicated that incompletely dry ISC had greater adsorption capacity for U(VI), with physical adsorption being the primary mechanism, whereas completely dry ISC exhibited much greater rigidity and much smaller volume. Therefore, initial absorption of U(VI) by incompletely dry ISC followed by heating could be compared with glass solidification for disposal of radioactive waste. The influence of solution pH, temperature, and contact time on U(VI) absorption was also studied, with pH being found to be the main influencing factor. The adsorption mechanism of completely dry ISC was explored by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, indicating that the main adsorption mechanism is chemical adsorption. (author)

  7. Evaluation of unconventional protein secretion in Saccharomyces cerevisiae.

    Science.gov (United States)

    Miura, Natsuko; Ueda, Mitsuyoshi

    2015-01-01

    Recent development of large-scale analyses such as the secretome analysis has enabled the discovery of a vast number of intracellular proteins that are secreted outside the cell. Often, these proteins do not contain any known signal sequence required for conventional protein secretion. In order to avoid misidentification of such "leaked" proteins as "secreted" proteins, reconstructing the process of protein secretion is essential. Here, we describe methods for the detection of reconstructed unconventional protein secretion and determination of regulatory proteins of secretion in Saccharomyces cerevisiae. We show that conjugating target proteins with a tag-sequence and utilizing various reagents and tools can facilitate quantitative detection of the secretion of target proteins. We expect that these methods will reveal novel unconventional secretion pathways of proteins. PMID:25702108

  8. ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2014-02-01

    Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

  9. Fermentation Temperature Modulates Phosphatidylethanolamine and Phosphatidylinositol Levels in the Cell Membrane of Saccharomyces cerevisiae

    OpenAIRE

    Henderson, Clark M.; Zeno, Wade F.; Lerno, Larry A.; Longo, Marjorie L.; Block, David E.

    2013-01-01

    During alcoholic fermentation, Saccharomyces cerevisiae is exposed to a host of environmental and physiological stresses. Extremes of fermentation temperature have previously been demonstrated to induce fermentation arrest under growth conditions that would otherwise result in complete sugar utilization at “normal” temperatures and nutrient levels. Fermentations were carried out at 15°C, 25°C, and 35°C in a defined high-sugar medium using three Saccharomyces cerevisiae strains with diverse fe...

  10. Influence of organic acids and organochlorinated insecticides on metabolism of Saccharomyces cerevisiae

    OpenAIRE

    Pejin Dušanka J.; Vasi? Vesna M.

    2005-01-01

    Saccharomyces cerevisiae is exposed to different stress factors during the production: osmotic, temperature, oxidative. The response to these stresses is the adaptive mechanism of cells. The raw materials Saccharomyces cerevisiae is produced from, contain metabolism products of present microorganisms and protective agents used during the growth of sugar beet for example the influence of acetic and butyric acid and organochlorinated insecticides, lindan and heptachlor, on the metabolism of Sac...

  11. Effect of Reserve Carbohydrates on Oxidative Stress in Yeast Saccharomyces cerevisiae Y6210

    OpenAIRE

    Smita Kanwal; R.K. Saharan; Mahmood, A.; Sharma, S.C.

    2011-01-01

    The aim of this study is investigate the role of reserve carbohydrates, trehalose and glycogen in DEM (Diethyl Maleate) induced oxidative stress in yeast Saccharomyces cerevisiae Y6210. Trehalose and glycogen accumulated in Saccharomyces cerevisiae, when growth conditions deteriorate. Yeast cells were subjected to oxidative stress for different time periods (0, 30, 60 and 120 min) to evaluate the role of trehalose, glycogen and trehalase. There was no change in the level of trehalose while th...

  12. Optimization of feeding strategy for the ergosterol production by yeasts Saccharomyces cerevisiae

    OpenAIRE

    Mojmir Rychtera; Josef Cermak; Jaroslav Votruba; Jan Nahlik; Karel Melzoch; Christopher A. Kent; Waldir D. Estela Escalante

    2010-01-01

    Objective of this study was to optimize ergosterol production by yeast strain Saccharomyces cerevisiae with the use of computer controlled feeding of cultivation medium. Baker´s yeasts strain of Saccharomyces cerevisiae originally modified and selected as mutant D7 was further applied in an industrial scale and also in this investigation. Composition of cultivation medium was optimized with the use of a modified Rosenbrock´s method with regard to following components: glucose, yeast extract, ...

  13. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation

    Science.gov (United States)

    Liu, Ling-ling; Jia, Bo; Zhao, Fang; Huang, Wei-dong; Zhan, Ji-cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China’s stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress. PMID:26030864

  14. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation.

    Science.gov (United States)

    Sun, Xiang-Yu; Zhao, Yu; Liu, Ling-Ling; Jia, Bo; Zhao, Fang; Huang, Wei-Dong; Zhan, Ji-Cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China's stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress. PMID:26030864

  15. Characterization of vacuolar amino acid transporter from Fusarium oxysporum in Saccharomyces cerevisiae.

    Science.gov (United States)

    Lunprom, Siriporn; Pongcharoen, Pongsanat; Sekito, Takayuki; Kawano-Kawada, Miyuki; Kakinuma, Yoshimi; Akiyama, Koichi

    2015-12-01

    Fusarium oxysporum causes wilt disease in many plant families, and many genes are involved in its development or growth in host plants. A recent study revealed that vacuolar amino acid transporters play an important role in spore formation in Schizosaccharomyces pombe and Saccharomyces cerevisiae. To investigate the role of vacuolar amino acid transporters of this phytopathogenic fungus, the FOXG_11334 (FoAVT3) gene from F. oxysporum was isolated and its function was characterized. Transcription of FoAVT3 was upregulated after rapamycin treatment. A green fluorescent protein fusion of FoAvt3p was localized to vacuolar membranes in both S. cerevisiae and F. oxysporum. Analysis of the amino acid content of the vacuolar fraction and amino acid transport activities using vacuolar membrane vesicles from S. cerevisiae cells heterologously expressing FoAVT3 revealed that FoAvt3p functions as a vacuolar amino acid transporter, exporting neutral amino acids. We conclude that the FoAVT3 gene encodes a vacuolar neutral amino acid transporter. PMID:26083447

  16. Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol

    Energy Technology Data Exchange (ETDEWEB)

    Steen, EricJ.; Chan, Rossana; Prasad, Nilu; Myers, Samuel; Petzold, Christopher; Redding, Alyssa; Ouellet, Mario; Keasling, JayD.

    2008-11-25

    BackgroundIncreasing energy costs and environmental concerns have motivated engineering microbes for the production of ?second generation? biofuels that have better properties than ethanol.Results& ConclusionsSaccharomyces cerevisiae was engineered with an n-butanol biosynthetic pathway, in which isozymes from a number of different organisms (S. cerevisiae, Escherichia coli, Clostridium beijerinckii, and Ralstonia eutropha) were substituted for the Clostridial enzymes and their effect on n-butanol production was compared. By choosing the appropriate isozymes, we were able to improve production of n-butanol ten-fold to 2.5 mg/L. The most productive strains harbored the C. beijerinckii 3-hydroxybutyryl-CoA dehydrogenase, which uses NADH as a co-factor, rather than the R. eutropha isozyme, which uses NADPH, and the acetoacetyl-CoA transferase from S. cerevisiae or E. coli rather than that from R. eutropha. Surprisingly, expression of the genes encoding the butyryl-CoA dehydrogenase from C. beijerinckii (bcd and etfAB) did not improve butanol production significantly as previously reported in E. coli. Using metabolite analysis, we were able to determine which steps in the n-butanol biosynthetic pathway were the most problematic and ripe for future improvement.

  17. [Construction of Saccharomyces cerevisiae mutant with knockout of SNF4 gene].

    Science.gov (United States)

    Lin, Xiaohua; Ke, Chongrong; Wu, Bisha; Zheng, Yongbiao; Li, Li; Chen, Youqiang; Huang, Jianzhong

    2011-04-01

    Construction and ethanol production effects of SNF4 gene knockout in Saccharomyces cerevisiae were described in this paper. For knockout of SNF4 gene in S. cerevisiae YS2, a PCR-amplified disruption cassette was used, encoding the short flanking homologous regions to the SNF4 gene and Kan(r) as selectable marker. The SNF4 gene disruption cassette was transformed into S. cerevisiae YS2 through LiAc/SS Carrier DNA/PEG. The positive transformants were grown on G418 plates and verified by PCR. The Kan(r) marker was rescued by transforming plasmid pSH65 into positive transformants and inducing expression of Cre recombinase in galactose-containing medium. Lastly, the YS2-deltaSNF4 strain, in which SNF4 allele gene were completely knocked out, was obtained by repeating the same procedure. The result of anaerobic fermentation showed that ethanol production of the SNF4 gene knockout strain had increased by 7.57 percent as compared with the original strain YS2. The experiment indicated ethanol production could be improved significantly with the approach ofSNF4 gene knockout by Cre-LoxP system. PMID:21847991

  18. Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol

    Directory of Open Access Journals (Sweden)

    Myers Samuel

    2008-12-01

    Full Text Available Abstract Background Increasing energy costs and environmental concerns have motivated engineering microbes for the production of "second generation" biofuels that have better properties than ethanol. Results and conclusion Saccharomyces cerevisiae was engineered with an n-butanol biosynthetic pathway, in which isozymes from a number of different organisms (S. cerevisiae, Escherichia coli, Clostridium beijerinckii, and Ralstonia eutropha were substituted for the Clostridial enzymes and their effect on n-butanol production was compared. By choosing the appropriate isozymes, we were able to improve production of n-butanol ten-fold to 2.5 mg/L. The most productive strains harbored the C. beijerinckii 3-hydroxybutyryl-CoA dehydrogenase, which uses NADH as a co-factor, rather than the R. eutropha isozyme, which uses NADPH, and the acetoacetyl-CoA transferase from S. cerevisiae or E. coli rather than that from R. eutropha. Surprisingly, expression of the genes encoding the butyryl-CoA dehydrogenase from C. beijerinckii (bcd and etfAB did not improve butanol production significantly as previously reported in E. coli. Using metabolite analysis, we were able to determine which steps in the n-butanol biosynthetic pathway were the most problematic and ripe for future improvement.

  19. Production of (S)-3-hydroxybutyrate by metabolically engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Yun, Eun Ju; Kwak, Suryang; Kim, Soo Rin; Park, Yong-Cheol; Jin, Yong-Su; Kim, Kyoung Heon

    2015-09-10

    (S)-3-Hydroxybutyrate (S-3HB) can be used as a precursor for the synthesis of biodegradable polymers such as polyhydroxyalkanoate and stereo-specific fine chemicals such as antibiotics, pheromones, and drugs. For the production of S-3HB in yeast, the biosynthetic pathway of S-3HB from acetyl-CoA, consisting of the three enzymes, acetyl-CoA C-acetyltransferase (ACCT), acetoacetyl-CoA reductase (ACR), and 3-hydroxybutyryl-CoA thioesterase (HBT), was introduced into Saccharomyces cerevisiae. An engineered yeast strain overexpressing ERG10, hbd, and tesB genes not only exhibited enzyme activities of AACT, ACR, and HBT, but also produced S-3HB from ethanol. In order to increase the titer of S-3HB, a fed-batch fermentation based on pulse feeding of ethanol as a carbon source was performed, and a final S-3HB titer of 12.0g/L was achieved. This is the first report on the production of 3HB by engineered yeast, utilizing ethanol as the carbon source, suggesting that the industrially preferred S. cerevisiae can be a promising host for producing S-3HB. PMID:26026703

  20. Long-chain alkane production by the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Buijs, Nicolaas A; Zhou, Yongjin J; Siewers, Verena; Nielsen, Jens

    2015-06-01

    In the past decade industrial-scale production of renewable transportation biofuels has been developed as an alternative to fossil fuels, with ethanol as the most prominent biofuel and yeast as the production organism of choice. However, ethanol is a less efficient substitute fuel for heavy-duty and maritime transportation as well as aviation due to its low energy density. Therefore, new types of biofuels, such as alkanes, are being developed that can be used as drop-in fuels and can substitute gasoline, diesel, and kerosene. Here, we describe for the first time the heterologous biosynthesis of long-chain alkanes by the yeast Saccharomyces cerevisiae. We show that elimination of the hexadecenal dehydrogenase Hfd1 and expression of a redox system are essential for alkane biosynthesis in yeast. Deletion of HFD1 together with expression of an alkane biosynthesis pathway resulted in the production of the alkanes tridecane, pentadecane, and heptadecane. Our study provides a proof of principle for producing long-chain alkanes in the industrial workhorse S. cerevisiae, which was so far limited to bacteria. We anticipate that these findings will be a key factor for further yeast engineering to enable industrial production of alkane based drop-in biofuels, which can allow the biofuel industry to diversify beyond bioethanol. PMID:25545362

  1. Exploring the Saccharomyces cerevisiae Volatile Metabolome: Indigenous versus Commercial Strains

    Science.gov (United States)

    Alves, Zélia; Melo, André; Figueiredo, Ana Raquel; Coimbra, Manuel A.; Gomes, Ana C.; Rocha, Sílvia M.

    2015-01-01

    Winemaking is a highly industrialized process and a number of commercial Saccharomyces cerevisiae strains are used around the world, neglecting the diversity of native yeast strains that are responsible for the production of wines peculiar flavours. The aim of this study was to in-depth establish the S. cerevisiae volatile metabolome and to assess inter-strains variability. To fulfill this objective, two indigenous strains (BT2652 and BT2453 isolated from spontaneous fermentation of grapes collected in Bairrada Appellation, Portugal) and two commercial strains (CSc1 and CSc2) S. cerevisiae were analysed using a methodology based on advanced multidimensional gas chromatography (HS-SPME/GC×GC-ToFMS) tandem with multivariate analysis. A total of 257 volatile metabolites were identified, distributed over the chemical families of acetals, acids, alcohols, aldehydes, ketones, terpenic compounds, esters, ethers, furan-type compounds, hydrocarbons, pyrans, pyrazines and S-compounds. Some of these families are related with metabolic pathways of amino acid, carbohydrate and fatty acid metabolism as well as mono and sesquiterpenic biosynthesis. Principal Component Analysis (PCA) was used with a dataset comprising all variables (257 volatile components), and a distinction was observed between commercial and indigenous strains, which suggests inter-strains variability. In a second step, a subset containing esters and terpenic compounds (C10 and C15), metabolites of particular relevance to wine aroma, was also analysed using PCA. The terpenic and ester profiles express the strains variability and their potential contribution to the wine aromas, specially the BT2453, which produced the higher terpenic content. This research contributes to understand the metabolic diversity of indigenous wine microflora versus commercial strains and achieved knowledge that may be further exploited to produce wines with peculiar aroma properties. PMID:26600152

  2. High level secretion of cellobiohydrolases by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Ahlgren Simon

    2011-09-01

    Full Text Available Abstract Background The main technological impediment to widespread utilization of lignocellulose for the production of fuels and chemicals is the lack of low-cost technologies to overcome its recalcitrance. Organisms that hydrolyze lignocellulose and produce a valuable product such as ethanol at a high rate and titer could significantly reduce the costs of biomass conversion technologies, and will allow separate conversion steps to be combined in a consolidated bioprocess (CBP. Development of Saccharomyces cerevisiae for CBP requires the high level secretion of cellulases, particularly cellobiohydrolases. Results We expressed various cellobiohydrolases to identify enzymes that were efficiently secreted by S. cerevisiae. For enhanced cellulose hydrolysis, we engineered bimodular derivatives of a well secreted enzyme that naturally lacks the carbohydrate-binding module, and constructed strains expressing combinations of cbh1 and cbh2 genes. Though there was significant variability in the enzyme levels produced, up to approximately 0.3 g/L CBH1 and approximately 1 g/L CBH2 could be produced in high cell density fermentations. Furthermore, we could show activation of the unfolded protein response as a result of cellobiohydrolase production. Finally, we report fermentation of microcrystalline cellulose (Avicel™ to ethanol by CBH-producing S. cerevisiae strains with the addition of beta-glucosidase. Conclusions Gene or protein specific features and compatibility with the host are important for efficient cellobiohydrolase secretion in yeast. The present work demonstrated that production of both CBH1 and CBH2 could be improved to levels where the barrier to CBH sufficiency in the hydrolysis of cellulose was overcome.

  3. Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hou, Jin; Österlund, Tobias

    2013-01-01

    The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often low due to limitations of the host strain. Heat shock response (HSR) is an inducible, global, cellular stress response, which facilitates the cell recovery from many forms of stress, e.g., heat stress. In S. cerevisiae, HSR is regulated mainly by the transcription factor heat shock factor (Hsf1p) and many of its targets are genes coding for molecular chaperones that promote protein folding and prevent the accumulation of mis-folded or aggregated proteins. In this work, we over-expressed a mutant HSF1 gene HSF1-R206S which can constitutively activate HSR, so the heat shock response was induced at different levels, and we studied the impact of HSR on heterologous protein secretion. We found that moderate and high level over-expression of HSF1-R206S increased heterologous ?-amylase yield 25 and 70 % when glucose was fully consumed, and 37 and 62 % at the end of the ethanol phase, respectively. Moderate and high level over-expression also improved endogenous invertase yield 118 and 94 %, respectively. However, human insulin precursor was only improved slightly and this only by high level over-expression of HSF1-R206S, supporting our previous findings that the production of this protein in S. cerevisiae is not limited by secretion. Our results provide an effective strategy to improve protein secretion and demonstrated an approach that can induce ER and cytosolic chaperones simultaneously.

  4. Estudo do equilíbrio e cinética da biossorção do pb2+ por saccharomyces cerevisiae / Equilibrium and kinetic study of pb2+ biosorption by saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Joelma Morais, Ferreira; Flávio Luiz Honorato da, Silva; Odelsia Leonor Sanchez, Alsina; Líbia de Sousa Conrado, Oliveira; Eliane Bezerra, Cavalcanti; Wolia Costa, Gomes.

    2007-10-01

    Full Text Available [...] Abstract in english The biosorption, based on the use of biomass for removal of ions is distinguished as an innovative and promising technology when compared with the traditional methods. In this context, the aim of the present work is to use Saccharomyces cerevisiae as biosorbent for the retention of Pb2+ metal ions. [...] Factorial design was used for evaluation of the process. The observed equilibrium data were well described by Langmuir and Freundlich adsorption isotherms. The maximum adsorption capacity was 1486.88 mg/g. The results indicated that Saccharomyces cerevisiae is suitable for biosorption of Pb2+ metal ions.

  5. Estudo do equilíbrio e cinética da biossorção do pb2+ por saccharomyces cerevisiae Equilibrium and kinetic study of pb2+ biosorption by saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Joelma Morais Ferreira

    2007-10-01

    Full Text Available The biosorption, based on the use of biomass for removal of ions is distinguished as an innovative and promising technology when compared with the traditional methods. In this context, the aim of the present work is to use Saccharomyces cerevisiae as biosorbent for the retention of Pb2+ metal ions. Factorial design was used for evaluation of the process. The observed equilibrium data were well described by Langmuir and Freundlich adsorption isotherms. The maximum adsorption capacity was 1486.88 mg/g. The results indicated that Saccharomyces cerevisiae is suitable for biosorption of Pb2+ metal ions.

  6. Invertase SUC2 Is the Key Hydrolase for Inulin Degradation in Saccharomyces cerevisiae

    OpenAIRE

    Wang, Shi-An; Li, Fu-Li

    2013-01-01

    Specific Saccharomyces cerevisiae strains were recently found to be capable of efficiently utilizing inulin, but genetic mechanisms of inulin hydrolysis in yeast remain unknown. Here we report functional characteristics of invertase SUC2 from strain JZ1C and demonstrate that SUC2 is the key enzyme responsible for inulin metabolism in S. cerevisiae.

  7. Efficient direct ethanol production from cellulose by cellulase- and cellodextrin transporter-co-expressing Saccharomyces cerevisiae

    OpenAIRE

    Yamada, Ryosuke; Nakatani, Yuki; Ogino, Chiaki; Kondo, Akihiko

    2013-01-01

    Efficient degradation of cellulosic biomass requires the synergistic action of the cellulolytic enzymes endoglucanase, cellobiohydrolase, and ?-glucosidase. Although there are many reports describing consolidation of hydrolysis and fermentation steps using recombinant Saccharomyces cerevisiae that express cellulolytic enzymes, the efficiency of cellulose degradation has not been sufficiently improved. Although the yeast S. cerevisiae cannot take up cellooligosaccharide, some fungi can take up...

  8. Viabilidade celular de Saccharomyces cerevisiae cultivada em associação com bactérias contaminantes da fermentação alcoólica Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminant bacteria of alcoholic fermentation

    OpenAIRE

    Thais de Paula Nobre; Jorge Horii; André Ricardo Alcarde

    2007-01-01

    O objetivo deste trabalho foi estudar a influência de bactérias dos gêneros Bacillus e Lactobacillus, bem como de seus produtos metabólicos, na redução da viabilidade celular de leveduras Saccharomyces cerevisiae. As bactérias Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus fermentum e Lactobacillus plantarum foram cultivadas em associação com a levedura S. cerevisiae (cepa Y-904) por 72 horas a 32 °C, sob agitação. A viabilidade celular, a taxa de brotam...

  9. Reconstruction of the biosynthetic pathway for the core fungal polyketide scaffold rubrofusarin in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Rugbjerg, Peter; Naesby, Michael

    2013-01-01

    ABSTRACT: BACKGROUND: Fungal polyketides include commercially important pharmaceuticals and food additives, e.g. the cholesterol-lowering statins and the red and orange monascus pigments. Presently, production relies on isolation of the compounds from the natural producers, and systems for heterologous production in easily fermentable and genetically engineerable organisms, such as Saccharomyces cerevisiae and Escherichia coli are desirable. Rubrofusarin is an orange polyketide pigment that is a common intermediate in many different fungal biosynthetic pathways. RESULTS: In this study, we established a biosynthetic pathway for rubrofusarin in S. cerevisiae. First, the Fusarium graminearum gene encoding polyketide synthase 12 (PKS12) was heterologously co-expressed with the Aspergillus fumigatus gene encoding phosphopantetheinyl transferase (npgA) resulting in production of YWA1. This aromatic heptaketide intermediate was converted into nor-rubrofusarin upon expression of the dehydratase gene aurZ from the aurofusarin gene cluster of F. graminearum. Final conversion into rubrofusarin was achieved by expression of the O-methyltransferase encoding gene aurJ, also obtained from the aurofusarin gene cluster, resulting in a titer of 1.1 mg/L. Reduced levels of rubrofusarin were detected when expressing PKS12, npgA, and aurJ alone, presumably due to spontaneous conversion of YWA1 to nor-rubrofusarin. However, the co-expression of aurZ resulted in an approx. six-fold increase in rubrofusarin production. CONCLUSIONS: The reconstructed pathway for rubrofusarin in S. cerevisiae allows the production of a core scaffold molecule with a branch-point role in several fungal polyketide pathways, thus paving the way for production of further natural pigments and bioactive molecules. Furthermore, the reconstruction verifies the suggested pathway, and as such, it is the first example of utilizing a synthetic biological “bottom up” approach for the validation of a complex fungal polyketide pathway.

  10. Systems Biology of Saccharomyces cerevisiae Physiology and its DNA Damage Response

    DEFF Research Database (Denmark)

    Fazio, Alessandro

    2010-01-01

    The yeast Saccharomyces cerevisiae is a model organism in biology, being widely used in fundamental research, the first eukaryotic organism to be fully sequenced and the platform for the development of many genomics techniques. Therefore, it is not surprising that S. cerevisiae has also been widely used in the field of systems biology during the last decade. This thesis investigates S. cerevisiae growth physiology and DNA damage response by using a systems biology approach. Elucidation of the re...

  11. Industrial Systems Biology of Saccharomyces cerevisiae Enables Novel Succinic Acid Cell Factory

    DEFF Research Database (Denmark)

    Otero, José Manuel; Cimini, Donatella; Patil, Kiran Raosaheb; Poulsen, Simon Guldberg; Olsson, Lisbeth; Nielsen, Jens

    2013-01-01

    Saccharomyces cerevisiae is the most well characterized eukaryote, the preferred microbial cell factory for the largest industrial biotechnology product (bioethanol), and a robust commerically compatible scaffold to be exploitted for diverse chemical production. Succinic acid is a highly sought after added-value chemical for which there is no native pre-disposition for production and accmulation in S. cerevisiae. The genome-scale metabolic network reconstruction of S. cerevisiae enabled in silic...

  12. Isolation of the catalase T structural gene of Saccharomyces cerevisiae by functional complementation.

    OpenAIRE

    Spevak, W; Fessl, F; Rytka, J; Traczyk, A; Skoneczny, M; Ruis, H

    1983-01-01

    The catalase T structural gene of Saccharomyces cerevisiae was cloned by functional complementation of a mutation causing specific lack of the enzyme (cttl). Catalase T-deficient mutants were obtained by UV mutagenesis of an S. cerevisiae strain bearing the cas1 mutation, which causes insensitivity of catalase T to glucose repression. Since the second catalase protein of S. cerevisiae, catalase A, is completely repressed on 10% glucose, catalase T-deficient mutant colonies could be detected u...

  13. Metabolic engineering of Saccharomyces cerevisiae microbial cell factories for succinic acid production

    DEFF Research Database (Denmark)

    Otero, José Manuel; Olsson, Lisbeth; Nielsen, Jens

    2007-01-01

    Saccharomyces cerevisiae is a proven, robust, industrial production platform used for expression of a wide range of therapeutic agents, high added-value chemicals, and commodities. Central carbon metabolism in S. cerevisiae has been extensively investigated using a wide variety of substrates for determination of how glycolytic flux is distributed across C1 (CO2,g), C2 (ethanol, acetate), and C3 (glycerol, pyruvate) products. For the S. cerevisiae CEN.PK113-7D strain cultivated under carbon-limit...

  14. Industrial Systems Biology of Saccharomyces cerevisiae Enables Novel Succinic Acid Cell Factory

    OpenAIRE

    Otero, José Manuel; Cimini, Donatella; Patil, Kiran Raosaheb; Poulsen, Simon Guldberg; Olsson, Lisbeth; Nielsen, Jens

    2013-01-01

    Saccharomyces cerevisiae is the most well characterized eukaryote, the preferred microbial cell factory for the largest industrial biotechnology product (bioethanol), and a robust commerically compatible scaffold to be exploitted for diverse chemical production. Succinic acid is a highly sought after added-value chemical for which there is no native pre-disposition for production and accmulation in S. cerevisiae. The genome-scale metabolic network reconstruction of S. cerevisiae enabled in si...

  15. Enhancing sesquiterpene production in Saccharomyces cerevisiae through in silico driven metabolic engineering

    DEFF Research Database (Denmark)

    Asadollahi, Mohammadali; Maury, Jerome

    2009-01-01

    A genome-scale metabolic model was used to identify new target genes for enhanced biosynthesis of sesquiterpenes in the yeast Saccharomyces cerevisiae. The effect of gene deletions on the flux distributions in the metabolic model of S. cerevisiae was assessed using OptGene as the modeling framework and minimization of metabolic adjustments (MOMA) as objective function. Deletion of NADPH-dependent glutamate dehydrogenase encoded by GDH1 was identified as the best target gene for the improvement of sesquiterpene biosynthesis in yeast. Deletion of this gene enhances the available NADPH in the cytosol for other NADPH requiring enzymes, including HMG-CoA reductase. However, since disruption of GDH1 impairs the ammonia utilization, simultaneous over-expression of the NADH-dependent glutamate dehydrogenase encoded by GDH2 was also considered in this study. Deletion of GDH1 led to an approximately 85% increase in the final cubebol titer. However, deletion of this gene also caused a significant decrease in the maximum specific growth rate. Over-expression of GDH2 did not show a further effect on the final cubebol titer but this alteration significantly improved the growth rate compared to the GDH1 deleted strain.

  16. Identification and analysis of the N(6)-methyladenosine in the Saccharomyces cerevisiae transcriptome.

    Science.gov (United States)

    Chen, Wei; Tran, Hong; Liang, Zhiyong; Lin, Hao; Zhang, Liqing

    2015-01-01

    Knowledge of the distribution of N(6)-methyladenosine (m(6)A) is invaluable for understanding RNA biological functions. However, limitation in experimental methods impedes the progress towards the identification of m(6)A site. As a complement of experimental methods, a support vector machine based-method is proposed to identify m(6)A sites in Saccharomyces cerevisiae genome. In this model, RNA sequences are encoded by their nucleotide chemical property and accumulated nucleotide frequency information. It is observed in the jackknife test that the accuracy achieved by the proposed model in identifying the m(6)A site was 78.15%. For the convenience of experimental scientists, a web-server for the proposed model is provided at http://lin.uestc.edu.cn/server/m6Apred.php. PMID:26343792

  17. Killer toxin of Saccharomyces cerevisiae Y500-4L active against Fleischmann and Itaiquara commercial brands of yeast

    Directory of Open Access Journals (Sweden)

    Soares Giselle A.M.

    1999-01-01

    Full Text Available The strain Saccharomyces cerevisiae Y500-4L, previously selected from the must of alcohol producing plants and showing high fermentative and killer capacities, was characterized according to the interactions between the yeasts and examined for curing and detection of dsRNA plasmids, which code for the killer character. The killer yeast S. cerevisiae Y500-4L showed considerable killer activity against the Fleischmann and Itaiquara commercial brands of yeast and also against the standard killer yeasts K2 (S. diastaticus NCYC 713, K4 (Candida glabrata NCYC 388 and K11 (Torulopsis glabrata ATCC 15126. However S. cerevisiae Y500-4L showed sensitivity to the killer toxin produced by the standard killer yeasts K8 (Hansenula anomala NCYC 435, K9 (Hansenula mrakii NCYC 500, K10 (Kluyveromyces drosophilarum NCYC 575 and K11 (Torulopsis glabrata ATCC 15126. No M-dsRNA plasmid was detected in the S. cerevisiae Y500-4L strain and these results suggest that the genetic basis for toxin production is encoded by chromosomal DNA. The strain S. cerevisiae Y500-4L was more resistant to the loss of the phenotype killer with cycloheximide and incubation at elevated temperatures (40oC than the standard killer yeast S. cerevisiae K1.

  18. ACÚMULO DE CÁDMIO POR Saccharomyces cerevisiae FERMENTANDO MOSTO DE MELAÇO

    Directory of Open Access Journals (Sweden)

    L.G. do PRADO-FILHO

    1998-01-01

    Full Text Available O presente trabalho visou o estudo do acúmulo de cádmio (Cd por Saccharomyces cerevisiae, fermentando mosto de melaço com contaminações controladas em níveis sub-tóxicos do citado metal. As condições de fermentação foram similares às reinantes na produção industrial de etanol. O mosto, não esterilizado, continha 12% de açúcares redutores totais (ART e pH 4,5. Para a contaminação controlada empregou-se dois sais de cádmio, cloreto e acetato e, quatro níveis de contaminação 0,5; 1,0; 2,0 e 5,0 mg Cd.kg-1 mosto. A inoculação do mosto foi executada com fermento de panificação (10% p/p. Após a fermentação (4 horas foram determinados, porcentagem de fermento no vinho centrifugado e teor alcoólico. Na levedura separada foram determinados peso úmido, matéria seca, proteína bruta e teores de cádmio por espectrofotometria de absorção atômica. Em todos os níveis de contaminação estudados houve acúmulo de Cd pela levedura e diminuição do rendimento em etanol.The aim of this paper was to study the cadmium (Cd accumulation by Saccharomyces cerevisiae fermenting wort of molasses, under sub-toxic levels of controlled cadmium contamination. Fermentation conditions were similar to industrial alcohol production. Non-sterelized wort had 12% of total reducing sugars (w/w and pH 4.5. For the controlled contamination, two cadmium salts were used (chloride and acetate, at four levels of contamination: 0.5; 1.0; 2.0 and 5.0 mg Cd.kg-1 wort. The inoculation of the wort was carried out with commercial bread yeast (10% w/w. After fermentation (4 hours, samples were evaluated for cellular viability, alcohol content and yeast percentage in the centrifuged wine. The centrifuged yeast cells were evaluated for total fresh and dry weight, total protein, and cadmium concentration by atomic absortion spectroscopy. In all Cd levels, there was cadmium accumulation by yeast and a decrease in ethanol yield.

  19. Regulation of Lactobacillus plantarum contamination on the carbohydrate and energy related metabolisms of Saccharomyces cerevisiae during bioethanol fermentation.

    Science.gov (United States)

    Dong, Shi-Jun; Lin, Xiang-Hua; Li, Hao

    2015-11-01

    During the industrial bioethanol fermentation, Saccharomyces cerevisiae cells are often stressed by bacterial contaminants, especially lactic acid bacteria. Generally, lactic acid bacteria contamination can inhibit S. cerevisiae cell growth through secreting lactic acid and competing with yeast cells for micronutrients and living space. However, whether are there still any other influences of lactic acid bacteria on yeast or not? In this study, Lactobacillus plantarum ATCC 8014 was co-cultivated with S. cerevisiae S288c to mimic the L. plantarum contamination in industrial bioethanol fermentation. The contaminative L. plantarum-associated expression changes of genes involved in carbohydrate and energy related metabolisms in S. cerevisiae cells were determined by quantitative real-time polymerase chain reaction to evaluate the influence of L. plantarum on carbon source utilization and energy related metabolism in yeast cells during bioethanol fermentation. Contaminative L. plantarum influenced the expression of most of genes which are responsible for encoding key enzymes involved in glucose related metabolisms in S. cerevisiae. Specific for, contaminated L. plantarum inhibited EMP pathway but promoted TCA cycle, glyoxylate cycle, HMP, glycerol synthesis pathway, and redox pathway in S. cerevisiae cells. In the presence of L. plantarum, the carbon flux in S. cerevisiae cells was redistributed from fermentation to respiratory and more reducing power was produced to deal with the excess NADH. Moreover, L. plantarum contamination might confer higher ethanol tolerance to yeast cells through promoting accumulation of glycerol. These results also highlighted our knowledge about relationship between contaminative lactic acid bacteria and S. cerevisiae during bioethanol fermentation. PMID:26279142

  20. Functional interaction between p21rap1A and components of the budding pathway in Saccharomyces cerevisiae.

    OpenAIRE

    McCabe, P C; Haubruck, H; Polakis, P; Mccormick, F.; Innis, M A

    1992-01-01

    The rap1A gene encodes a 21-kDa, ras-related GTP-binding protein (p21rap1A) of unknown function. A close structural homolog of p21rap1A (65% identity in the amino-terminal two-thirds) is the RSR1 gene product (Rsr1p) of Saccharomyces cerevisiae. Although Rsr1p is not essential for growth, its presence is required for nonrandom selection of bud sites. To assess the similarity of these proteins at the functional level, wild-type and mutant forms of p21rap1A were tested for complementation of ac...

  1. Cloning and characterization of hOGG1, a human homolog of the OGG1 gene of Saccharomyces?cerevisiae

    OpenAIRE

    Radicella, J.Pablo; Dherin, Claudine; Desmaze, Chantal; Fox, Maurice S.; Boiteux, Serge

    1997-01-01

    The OGG1 gene of Saccharomyces cerevisiae encodes a DNA glycosylase activity that is a functional analog of the Fpg protein from Escherichia coli and excises 7,8-dihydro-8-oxoguanine (8-oxoG) from damaged DNA. The repair of this ubiquitous kind of oxidative damage is essential to prevent mutations both in bacteria and in yeast. A human cDNA clone carrying an ORF displaying homology to the yeast protein was identified. The predicted protein has 345 amino acids and a molecular mass of 39 kDa. T...

  2. Binding protein BiP is required for translocation of secretory proteins into the endoplasmic reticulum in Saccharomyces cerevisiae.

    OpenAIRE

    Nguyen, T. H.; Law, D T; Williams, D. B.

    1991-01-01

    The endoplasmic reticulum of mammalian cells contains a heat shock protein of approximately 70 kDa (hsp70) termed binding protein BiP that is thought to promote the folding and subunit assembly of newly synthesized proteins. To study BiP function, we placed the BiP-encoding gene from Saccharomyces cerevisiae under the control of a regulated promoter and examined the effects of BiP depletion. Reduction of BiP protein to about 15% of normal levels led to a profound reduction in secretion of alp...

  3. The level of glucose-6-phosphate dehydrogenase activity strongly influences xylose fermentation and inhibitor sensitivity in recombinant Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    Jeppsson, M.; Johansson, B.; Jensen, Peter Ruhdal; Hahn-Hagerdal, B.; Gorwa-Grauslund, M.F.

    2003-01-01

    Disruption of the ZWF1 gene encoding glucose-6-phosphate dehydrogenase (G6PDH) has been shown to reduce the xylitol yield and the xylose consumption in the xylose-utilizing recombinant Saccharomyces cerevisiae strain TMB3255. In the present investigation we have studied the influence of different production levels of G6PDH on xylose fermentation. We used a synthetic promoter library and the copper-regulated CUP1 promoter to generate G6PDH-activities between 0% and 179% of the wildtype level. G6P...

  4. Structure of the DNA damage-inducible gene DDR48 and evidence for its role in mutagenesis in Saccharomyces cerevisiae.

    OpenAIRE

    Treger, J M; McEntee, K

    1990-01-01

    The DDR48 gene of Saccharomyces cerevisiae is a member of a set of genes that displays increased transcription in response to treatments that produce DNA lesions or to heat-shock stress. Other members of this group include the DDRA2 and UBI4 genes. DNA sequence analysis of the DDR48 gene demonstrates the presence of two overlapping open reading frames, each of which has the capacity to encode a protein with a molecular mass of approximately 45 kilodaltons. Fusions of the DDR48 coding sequence...

  5. mRNA quality control pathways in Saccharomyces cerevisiae

    Indian Academy of Sciences (India)

    Satarupa Das; Biswadip Das

    2013-09-01

    Efficient production of translation-competent mRNAs involves processing and modification events both in the nucleus and cytoplasm which require a number of complex machineries at both co-transcriptional and post-transcriptional levels. Mutations in the genomic sequence sometimes result in the formation of mutant non-functional defective messages. In addition, the enormous amounts of complexities involved in the biogenesis of mRNPs in the nucleus very often leads to the formation of aberrant and faulty messages along with their functional counterpart. Subsequent translation of these mutant and defective populations of messenger RNAs could possibly result in the unfaithful transmission of genetic information and thus is considered a threat to the survival of the cell. To prevent this possibility, mRNA quality control systems have evolved both in the nucleus and cytoplasm in eukaryotes to scrutinize various stages of mRNP biogenesis and translation. In this review, we will focus on the physiological role of some of these mRNA quality control systems in the simplest model eukaryote Saccharomyces cerevisiae.

  6. MAP kinase pathways in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Gustin, M. C.; Albertyn, J.; Alexander, M.; Davenport, K.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    A cascade of three protein kinases known as a mitogen-activated protein kinase (MAPK) cascade is commonly found as part of the signaling pathways in eukaryotic cells. Almost two decades of genetic and biochemical experimentation plus the recently completed DNA sequence of the Saccharomyces cerevisiae genome have revealed just five functionally distinct MAPK cascades in this yeast. Sexual conjugation, cell growth, and adaptation to stress, for example, all require MAPK-mediated cellular responses. A primary function of these cascades appears to be the regulation of gene expression in response to extracellular signals or as part of specific developmental processes. In addition, the MAPK cascades often appear to regulate the cell cycle and vice versa. Despite the success of the gene hunter era in revealing these pathways, there are still many significant gaps in our knowledge of the molecular mechanisms for activation of these cascades and how the cascades regulate cell function. For example, comparison of different yeast signaling pathways reveals a surprising variety of different types of upstream signaling proteins that function to activate a MAPK cascade, yet how the upstream proteins actually activate the cascade remains unclear. We also know that the yeast MAPK pathways regulate each other and interact with other signaling pathways to produce a coordinated pattern of gene expression, but the molecular mechanisms of this cross talk are poorly understood. This review is therefore an attempt to present the current knowledge of MAPK pathways in yeast and some directions for future research in this area.

  7. Metabolic engineering of Saccharomyces cerevisiae for caffeine and theobromine production.

    Science.gov (United States)

    Jin, Lu; Bhuiya, Mohammad Wadud; Li, Mengmeng; Liu, XiangQi; Han, Jixiang; Deng, WeiWei; Wang, Min; Yu, Oliver; Zhang, Zhengzhu

    2014-01-01

    Caffeine (1, 3, 7-trimethylxanthine) and theobromine (3, 7-dimethylxanthine) are the major purine alkaloids in plants, e.g., tea (Camellia sinensis) and coffee (Coffea arabica). Caffeine is a major component of coffee and is used widely in food and beverage industries. Most of the enzymes involved in the caffeine biosynthetic pathway have been reported previously. Here, we demonstrated the biosynthesis of caffeine (0.38 mg/L) by co-expression of Coffea arabica xanthosine methyltransferase (CaXMT) and Camellia sinensis caffeine synthase (TCS) in Saccharomyces cerevisiae. Furthermore, we endeavored to develop this production platform for making other purine-based alkaloids. To increase the catalytic activity of TCS in an effort to increase theobromine production, we identified four amino acid residues based on structural analyses of 3D-model of TCS. Two TCS1 mutants (Val317Met and Phe217Trp) slightly increased in theobromine accumulation and simultaneously decreased in caffeine production. The application and further optimization of this biosynthetic platform are discussed. PMID:25133732

  8. Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hou, Jin; Lages, Nuno

    2009-01-01

    Redox cofactors play a pivotal role in coupling catabolism with anabolism and energy generation during metabolism. There exists a delicate balance in the intracellular level of these cofactors to ascertain an optimal metabolic output. Therefore, cofactors are emerging to be attractive targets to induce widespread changes in metabolism. We present a detailed analysis of the impact of perturbations in redox cofactors in the cytosol or mitochondria on glucose and energy metabolism in Saccharomyces cerevisiae to aid metabolic engineering decisions that involve cofactor engineering. We enhanced NADH oxidation by introducing NADH oxidase or alternative oxidase, its ATP-mediated conversion to NADPH using NADH kinase as well as the interconversion of NADH and NADPH independent of ATP by the soluble, non-proton-translocating bacterial transhydrogenase. Decreasing cytosolic NADH level lowered glycerol production, while decreasing mitochondrial NADH lowered ethanol production. However, when these reactions were coupled with NADPH production, the metabolic changes were more moderated. The direct consequence of these perturbations could be seen in the shift of the intracellular concentrations of the cofactors. The changes in product profile and intracellular metabolite levels were closely linked to the ATP requirement for biomass synthesis and the efficiency of oxidative phosphorylation, as estimated from a simple stoichiometric model. The results presented here will provide valuable insights for a quantitative understanding and prediction of cellular response to redox-based perturbations for metabolic engineering applications.

  9. Metabolomic analysis of acid stress response in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nugroho, Riyanto Heru; Yoshikawa, Katsunori; Shimizu, Hiroshi

    2015-10-01

    Acid stress has been reported to inhibit cell growth and decrease productivity during bio-production processes. In this study, a metabolomics approach was conducted to understand the effect of lactic acid induced stress on metabolite pools in Saccharomyces cerevisiae. Cells were cultured with lactic acid as the acidulant, with or without initial pH control, i.e., at pH 6 or pH 2.5, respectively. Under conditions of low pH, lactic acid led to a decrease in the intracellular pH and specific growth rate; however, these parameters remained unaltered in the cultures with pH control. Capillary electrophoresis-mass spectrometry followed by a statistical principal component analysis was used to identify the metabolites and measure the increased concentrations of ATP, glutathione and proline during severe acid stress. Addition of proline to the acidified cultures improved the specific growth rates. We hypothesized that addition of proline protected the cells from acid stress by combating acid-induced oxidative stress. Lactic acid diffusion into the cell resulted in intracellular acidification, which elicited an oxidative stress response and resulted in increased glutathione levels. PMID:25795572

  10. Structure of the RACK1 dimer from Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Yatime, Laure; Hein, Kim Langemach

    2011-01-01

    Receptor for activated C-kinase 1 (RACK1) serves as a scaffolding protein in numerous signaling pathways involving kinases and membrane-bound receptors from different cellular compartments. It exists simultaneously as a cytosolic free form and as a ribosome-bound protein. As part of the 40S ribosomal subunit, it triggers translational regulation by establishing a direct link between protein kinase C and the protein synthesis machinery. It has been suggested that RACK1 could recruit other signaling molecules onto the ribosome, providing a signal-specific modulation of the translational process. RACK1 is able to dimerize both in vitro and in vivo. This homodimer formation has been observed in several processes including the regulation of the N-methyl-d-aspartate receptor by the Fyn kinase in the brain and the oxygen-independent degradation of hypoxia-inducible factor 1. The functional relevance of this dimerization is, however, still unclear and the question of a possible dimerization of the ribosome-bound protein is still pending. Here, we report the first structure of a RACK1 homodimer, as determined from two independent crystal forms of the Saccharomyces cerevisiae RACK1 protein (also known as Asc1p) at 2.9 and 3.9 Å resolution. The structure reveals an atypical mode of dimerization where monomers intertwine on blade 4, thus exposing a novel surface of the protein to potential interacting partners. We discuss the significance of the dimer structure for RACK1 function.

  11. Metabolic engineering of Saccharomyces cerevisiae to improve 1-hexadecanol production.

    Science.gov (United States)

    Feng, Xueyang; Lian, Jiazhang; Zhao, Huimin

    2015-01-01

    Fatty alcohols are important components of a vast array of surfactants, lubricants, detergents, pharmaceuticals and cosmetics. We have engineered Saccharomyces cerevisiae to produce 1-hexadecanol by expressing a fatty acyl-CoA reductase (FAR) from barn owl (Tyto alba). In order to improve fatty alcohol production, we have manipulated both the structural genes and the regulatory genes in yeast lipid metabolism. The acetyl-CoA carboxylase gene (ACC1) was over-expressed, which improved 1-hexadecanol production by 56% (from 45mg/L to 71mg/L). Knocking out the negative regulator of the INO1 gene in phospholipid metabolism, RPD3, further enhanced 1-hexadecanol production by 98% (from 71mg/L to 140mg/L). The cytosolic acetyl-CoA supply was next engineered by expressing a heterologous ATP-dependent citrate lyase, which increased the production of 1-hexadecanol by an additional 136% (from 140mg/L to 330mg/L). Through fed-batch fermentation using resting cells, over 1.1g/L 1-hexadecanol can be produced in glucose minimal medium, which represents the highest titer reported in yeast to date. PMID:25466225

  12. Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.

    Science.gov (United States)

    Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie; Courtin, Christophe M; Verstrepen, Kevin J

    2013-12-01

    The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation. PMID:24056467

  13. Heterologous Expression of Syntaxin 6 in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    MARTIN GÖTTE

    2002-01-01

    Full Text Available The molecular mechanisms of vesicular protein transport in eukaryotic cells are highly conserved. Members of the syntaxin family play a pivotal role in the membrane fusion process. We have expressed rat syntaxin 6 and its cytoplasmic domain in wild-type and pep12 mutant strains of Saccharomyces cerevisiae to elucidate the role of the syntaxin 6-dependent vesicular trafficking step in yeast. Immunofluorescence microscopy revealed a punctate, Golgi-like staining pattern for syntaxin 6, which only partially overlapped with Pep12p in wild-type yeast cells. In contrast to Pep12p, syntaxin 6 was not mislocalized to the vacuole upon expression from 2 micron vectors, which might be attributed to conserved sorting and retention signals. Syntaxin 6 was not capable of complementing the sorting and maturation defects of the vacuolar hydrolase CPY in pep12 null mutants. No dominant negative effects of either syntaxin 6 or syntaxin 6deltaC overexpression on CPY sorting and maturation were observed in wild-type yeast cells. We conclude that syntaxin 6 and Pep12p do not act at the same vesicular trafficking step(s in yeast and higher eukaryotes

  14. Fermentação de trealose e glicogênio endógenos em Saccharomyces cerevisiae Fermentation of endogenous trehalose and glycogen by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    L.V. FERREIRA

    1999-01-01

    Full Text Available As linhagens PE-2 e VR-1 de Saccharomyces cerevisiae foram submetidas à fermentação das reservas endógenas na temperatura de 40oC. No intervalo de 0 a 24 horas foram recolhidas as amostras para a determinação de etanol, nitrogênio no fermento e no vinho, bem como os carboidratos de reserva (trealose e glicogênio e a viabilidade celular. A trealose foi esgotada durante 24 horas. Os teores de glicogênio sofreram muitas oscilações ao longo do tempo, entre a mobilização e a síntese e embora não esgotado, deve ter contribuído significativamente para a formação de álcool na suspensão. Foi observada a relação proporcional entre a mobilização de trealose e a queda da viabilidade celular. No transcorrer da fermentação das reservas de carboidratos houve aumento nos teores de nitrogênio no fermento até 6 e 8 horas, sendo tal incremento afetado pela linhagem de levedura. No prosseguimento da fermentação ocorreu a autólise celular, que foi percebida pelo aumento brusco de nitrogênio no vinho (de 200 para 1500mg/L e pela queda da viabilidade celular. O ganho alcançado com a fermentação endógena foi de 40 e 68 litros de álcool por tonelada de levedura seca com incremento de 25 e 27% de proteína no fermento para as linhagens PE-2 e VR-1, respectivamente. Este resultado tem reflexos positivos quando da comercialização da levedura seca como proteína microbiana.Two Saccharomyces cerevisiae strains (PE-2 and VR-1 were subjected to fermentation of its carbohidrate reserve (Trehalose and glycogen at 40oC. During a 24 hours interval samples were collected for determination of ethanol, yeast and wine nitrogen, yeast trehalose, glycogen and cell viability. Trehalose was completely exhausted after 24 hours. Glycogen was not completely consumed, but probably contributes for ethanol formation. As trehalose is consumed yeast cell viability decreases, while yeast nitrogen content increase, reaching a maximum between 6 and 8 hours, depending on the yeast strain. If yeast is maintained under prolonged stressing conditions, cell autolysis occurs and nitrogen is lost to the medium, increasing from 200 to 1500mg/L. Such endogenous fermentation allows a production of 40 to 68L of ethanol per ton of dry yeast, with yeast nitrogen increasing of 25 and 27% for PE-2 and VR-1, respectively.

  15. Fermentação de trealose e glicogênio endógenos em Saccharomyces cerevisiae / Fermentation of endogenous trehalose and glycogen by Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    L.V., FERREIRA; H.V., AMORIM; L.C., BASSO.

    1999-01-01

    Full Text Available As linhagens PE-2 e VR-1 de Saccharomyces cerevisiae foram submetidas à fermentação das reservas endógenas na temperatura de 40oC. No intervalo de 0 a 24 horas foram recolhidas as amostras para a determinação de etanol, nitrogênio no fermento e no vinho, bem como os carboidratos de reserva (trealose [...] e glicogênio) e a viabilidade celular. A trealose foi esgotada durante 24 horas. Os teores de glicogênio sofreram muitas oscilações ao longo do tempo, entre a mobilização e a síntese e embora não esgotado, deve ter contribuído significativamente para a formação de álcool na suspensão. Foi observada a relação proporcional entre a mobilização de trealose e a queda da viabilidade celular. No transcorrer da fermentação das reservas de carboidratos houve aumento nos teores de nitrogênio no fermento até 6 e 8 horas, sendo tal incremento afetado pela linhagem de levedura. No prosseguimento da fermentação ocorreu a autólise celular, que foi percebida pelo aumento brusco de nitrogênio no vinho (de 200 para 1500mg/L) e pela queda da viabilidade celular. O ganho alcançado com a fermentação endógena foi de 40 e 68 litros de álcool por tonelada de levedura seca com incremento de 25 e 27% de proteína no fermento para as linhagens PE-2 e VR-1, respectivamente. Este resultado tem reflexos positivos quando da comercialização da levedura seca como proteína microbiana. Abstract in english Two Saccharomyces cerevisiae strains (PE-2 and VR-1) were subjected to fermentation of its carbohidrate reserve (Trehalose and glycogen) at 40oC. During a 24 hours interval samples were collected for determination of ethanol, yeast and wine nitrogen, yeast trehalose, glycogen and cell viability. Tre [...] halose was completely exhausted after 24 hours. Glycogen was not completely consumed, but probably contributes for ethanol formation. As trehalose is consumed yeast cell viability decreases, while yeast nitrogen content increase, reaching a maximum between 6 and 8 hours, depending on the yeast strain. If yeast is maintained under prolonged stressing conditions, cell autolysis occurs and nitrogen is lost to the medium, increasing from 200 to 1500mg/L. Such endogenous fermentation allows a production of 40 to 68L of ethanol per ton of dry yeast, with yeast nitrogen increasing of 25 and 27% for PE-2 and VR-1, respectively.

  16. [Construction of Saccharomyces cerevisiae haploid mutant deficient in lanosterol synthase gene].

    Science.gov (United States)

    Gao, Li-Li; Wang, Qing-Hua; Liang, Hui-Chao; Gong, Ting; Yang, Jin-Ling; Zhu, Ping

    2014-05-01

    Lanosterol synthase is encoded by the erg7 gene and catalyzes the cyclization of 2, 3-oxidosqualene, which is a rate-limiting step of the inherent mevalonate (MVA)/ergosterol metabolic pathway in Saccharomyces cerevisiae. The intermediate 2, 3-oxidosqualene is also the precursor of triterpenoids. Therefore, the cyclization of 2, 3-oxidosqualene is the key branch point of ergosterol and triterpenoids biosynthesis. Down-regulation of 2, 3-oxidosqualene metabolic flux to ergosterol in S. cerevisiae may redirect the metabolic flux toward the triterpenoid synthetic pathway reconstructed by the synthetic biology approach. To construct erg7 knockout cassette harboring the loxP-Marker-loxP element, long primers were designed, which were homologous to the sequences of both erg7 ORF and plasmid pUG66. The cassette was transformed into diploid wild strain INVSc1 by LiAc/SS Carrier DNA/PEG method and then erg7 gene haploid deficient mutant was obtained by homologous recombination. The results of semiquantitative PCR and real-time quantitative PCR revealed that erg7 expression level in erg7 gene haploid deficient mutant is one time lower than that in wild strain. The results of TLC and HPLC showed that the ergosterol content in deficient mutant decreased to 42% of that in wild strain. PMID:25151749

  17. [Expression of delta 6-fatty acid desaturase gene from Mortierella alpina in Saccharomyces cerevisiae].

    Science.gov (United States)

    Liu, L; Li, M C; Hu, G W; Ge, J; Zhang, L; Cheng, Z H; Xing, L J

    2001-03-01

    delta 6-fatty acid desaturase is the rate-limiting enzyme of the desaturation of linoleic acid in the production of an essential fatty acid, gamma-linolenic acid. The 1.4 kb fragment in plasmid pTMACL6 encoding delta 6-fatty acid desaturase from Mortieralla alpina ATCC16266 was subcloned into the yeast-E. coli shuttle vector pYES2.0, thus an expression recombinant plasmid pYMAD6 containing target gene was constructed and obtained in the SC-Ura media. The pYMAD6 was introduced into defective mutant INCSc1 of Saccharomyces cerevisiae by LiAc method. When linoleic acid was provided as an exogenous substrate to the yeast cultures expressing delta 6-fatty acid desaturase activity under appropriate media and temperature condition, the level of gamma-linolenic acid reached 31.6% of the total yeast fatty acids by GC-MS detecting, which is the highest report of delta 6-fatty-acid desaturase gene in S. cerevisiae. PMID:11411223

  18. A novel approach for the improvement of ethanol fermentation by Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Hou, L.; Cao, X.; Wang, C. [Tianjin Univ. of Science and Technology, Tianjin (China). Key Laboratory of Food Nutrition and Safety

    2010-06-15

    The partial substitution of fossil fuels with bioethanol has become an important strategy for the use of renewable energy. Ethanol production is generally achieved through fermentation of starch or sugar-based feedstock by Saccharomyces cerevisiae. In order to meet the growing demand for ethanol, there is a need for new yeast strains that can produce ethanol more efficiently and cost effectively. This paper presented a new genome engineering approach that was developed to improve ethanol production by S. cerevisiae. In this study, the aneuploid strain constructed on the base of tetraploid cells was shown to have favourable metabolic traits in very high gravity (VHG) fermentation with 300 g/L glucose as the carbon source. The tetraploid strain was constructed using the plasmid YCplac33-GHK, which comprised the HO gene encoding the site-specific HO endonucleases. The aneuploid strain, WT4-M, was chosen and screened once the tetraploid cells were treated with methyl benzimidazole-2-yl-carbamate to induce loss of mitotic chromosomes. The aneuploid strain WT4-M increased ethanol production as well as osmotic and thermal tolerance. The sugar to ethanol conversion rate also improved. It was concluded that this new approach is valuable for creating yeast strains with better fermentation characteristics. 25 refs., 3 figs.

  19. De novo production of resveratrol from glucose or ethanol by engineered Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Li, Mingji; Kildegaard, Kanchana Rueksomtawin

    2015-01-01

    Resveratrol is a natural antioxidant compound, used as food supplement and cosmetic ingredient. Microbial production of resveratrol has until now been achieved by supplementation of expensive substrates, p-coumaric acid or aromatic amino acids. Here we engineered the yeast Saccharomyces cerevisiae to produce resveratrol directly from glucose or ethanol via tyrosine intermediate. First we introduced the biosynthetic pathway, consisting of tyrosine ammonia-lyase from Herpetosiphon aurantiacus, 4-coumaryl-CoA ligase from Arabidopsis thaliana and resveratrol synthase from Vitis vinifera, and obtained 2.73±0.05 mg L?1 resveratrol from glucose. Then we over-expressed feedback-insensitive alleles of ARO4 encoding 3-deoxy-D-arabino-heptulosonate-7-phosphate and ARO7 encoding chorismate mutase, resulting in production of 4.85±0.31 mg L?1 resveratrol from glucose as the sole carbon source. Next we improved the supply of the precursor malonyl-CoA by over-expressing a post-translational de-regulated version of the acetyl-CoA carboxylase encoding gene ACC1; this strategy further increased resveratrol production to 6.39±0.03 mg L?1. Subsequently, we improved the strain by performing multiple-integration of pathway genes resulting in resveratrol production of 235.57±7.00 mg L?1. Finally, fed-batch fermentation of the final strain with glucose or ethanol as carbon source resulted in a resveratrol titer of 415.65 and 531.41 mg L?1, respectively.

  20. Low oxygen levels as a trigger for enhancement of respiratory metabolism in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Wiebe Marilyn G

    2009-10-01

    Full Text Available Abstract Background The industrially important yeast Saccharomyces cerevisiae is able to grow both in the presence and absence of oxygen. However, the regulation of its metabolism in conditions of intermediate oxygen availability is not well characterised. We assessed the effect of oxygen provision on the transcriptome and proteome of S. cerevisiae in glucose-limited chemostat cultivations in anaerobic and aerobic conditions, and with three intermediate (0.5, 1.0 and 2.8% oxygen levels of oxygen in the feed gas. Results The main differences in the transcriptome were observed in the comparison of fully aerobic, intermediate oxygen and anaerobic conditions, while the transcriptome was generally unchanged in conditions receiving different intermediate levels (0.5, 1.0 or 2.8% O2 of oxygen in the feed gas. Comparison of the transcriptome and proteome data suggested post-transcriptional regulation was important, especially in 0.5% oxygen. In the conditions of intermediate oxygen, the genes encoding enzymes of the respiratory pathway were more highly expressed than in either aerobic or anaerobic conditions. A similar trend was also seen in the proteome and in enzyme activities of the TCA cycle. Further, genes encoding proteins of the mitochondrial translation machinery were present at higher levels in all oxygen-limited and anaerobic conditions, compared to fully aerobic conditions. Conclusion Global upregulation of genes encoding components of the respiratory pathway under conditions of intermediate oxygen suggested a regulatory mechanism to control these genes as a response to the need of more efficient energy production. Further, cells grown in three different intermediate oxygen levels were highly similar at the level of transcription, while they differed at the proteome level, suggesting post-transcriptional mechanisms leading to distinct physiological modes of respiro-fermentative metabolism.

  1. Cellular responses of Saccharomyces cerevisiae to DNA damage

    International Nuclear Information System (INIS)

    Full text. Several experimental strategies have been used to study responses of S. cerevisiae cells to DNA damage. One approach was based on the isolation of novel genes, the expression of which is induced by lesions in DNA. One of these genes, DIN7, was cloned and partially characterized previously. The product of DIN7 belongs to a large family of proteins involved in DNA repair and mutagenesis. This family includes Rad2, Rad27 and ExoI proteins of S. cerevisiae and their respective human homologues, all of which are endowed with DNA nuclease activity. To study cellular function of Din7 we constructed the pPK3 plasmid carrying DIN7 fused to the GAL1 promoter. Effects of DIN7 overproduction on the phenotypes of wild-type cells and of rad27 and exoI mutants were examined. Overproduction of Din7 does not seem to affect the proficiency of wild-type S. cerevisiae cells in recombination and mutagenesis. Also, overexpression of DIN7 does not suppress the deficiency of the EXOI gene product, the closest homologue of Din7, both in recombination and in controlling the fidelity of DNA replication. Unexpectedly, we found that elevated levels of Din7 result in a very high frequency of mitochondrial rho- mutants. A high frequency of production of rho- mutants wa s also observed in strains defective in the functioning of the Dun1 protein kinase involved in signal transmission in cells exposed to DNA damaging agents. Interestingly, deficiency of Dun1 results also in a significant derepression of the DIN7 gene. Experiments are under way to distinguish whether a high cellular level of Din7 specifically decreases stability of mitochondrial DNA or affects stability of chromosomal DNA as well. Analysis of previously constructed S. cerevisiae strains carrying random geno mic fusions with reporter lacZ gene, allowed us to identify the reading frame YBR173c, on chromosome II as a novel damage inducible gene - DIN8. We have shown that DIN8-lacZ fusion is induced in yeast cells treated with MMS or exposed to UV light. Northern RNA analysis indicates that DIN8 is induced in response to DNA damage at the transcriptional level. DIN8 was cloned and the phenotype of cells with disruption of the gene is under study. POL2-MEC1-RAD53-DUN1-signal transducing pathway has recently been postulated to be involved in the regulation of response of S. cerevisiae cells to DNA-damaging agents. We analyzed the expression of a known damage inducible DNA-repair gene, MAG1, encoding 3-methyladenine glycosylase, in S. cerevisiae strains carrying MAG1 ::lacZ fusion and deficient in either POL2, MEC1, RAD53 or DUN1 function. ?-galactosidase activity was assayed in cycling cells exposed to MMS or UV light. It was found that, in contrast to model DNA damage inducible RNR genes, neither mutation in t he sensory C-terminal part of polymerase ? (pol2-11) nor the in the Mec1, Sad1/Rad53 or Dun1 cellular kinases blocks the induction of MAG1 in response to MMS or UV light in cycling yeasts. (author)

  2. Expresión heteróloga de un péptido multiepitópico de células B de M. tuberculosis en Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Norazmi Mohd Nor

    2007-01-01

    Full Text Available Saccharomyces cerevisiae ha sido ampliamente utilizada como sistema de expresión de proteínas heterólogas. El presente trabajo se encaminó hacia la expresión en Saccharomyces cerevisiae de un péptido de epitopes múltiples de M. tuberculosis. Con dicho propósito el péptido quimérico denominado B2 fue clonado en dos vectores de expresión de esta levadura con promotores regulables por galactosa y sulfato cúprico, respectivamente. Luego de los experimentos de inducción, la expresión del péptido B2 se analizó mediante SDS/PAGE y Western blot. El análisis por Western blot confirmó la expresión del péptido B2, al hacerse la inducción con 100 ?M de CuSO4 durante toda la noche. No ocurrió así en los experimentos donde se utilizó la galactosa como inductor con todas las condiciones ensayadas. Estos resultados mostraron que la levadura Saccharomyces cerevisiae pudiera ser un buen hospedero alternativo para la expresión de péptidos multiepitópicos de M. tuberculosis.

  3. Prevalence reduction of pathogens in poultry fed with Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Fanelli, A.

    2015-01-01

    Full Text Available Description of the subject. The growth of new antibiotic-resistant strains of pathogens represents a huge problem in poultry rearing. There is evidence that dietary yeast could be effective in the protection against a variety of pathogens that can affect poultry health and cause foodborne diseases in humans. Since still few or contradictory information are available for this topic. Objectives. The objective of this study was to investigate the effects of live yeast supplementation in broiler chickens on Salmonella enteritidis and Campylobacter jejuni content in feces, cecum, and skin. Method. Supplemented yeast consisted of Saccharomyces cerevisiae (Levucell® SB20, type boulardii I-1079, Lallemand, France and was administered at a rate of 1 x 106 CFU·g-1 of feed. On day ten of life, birds were orally challenged with S. enteritidis (1 x 105 CFU/bird and C. jejuni (3 x 105 CFU/bird. Growth performance, and coliforms, yeasts and lactobacilli enumeration were evaluated on day 0, 10, 20 and 38. Ten and eighteen days post infection (PI, 10 animals per replicate were slaughtered and pooled ceca content were analyzed for yeast enumeration and Salmonella and Campylobacter frequency and enumeration. The presence and the enumeration of Salmonella and Campylobacter in neck and breast skin were performed on one subject per replicate. Results. Dietary S. cerevisiae increased yeast and lactobacilli (p = 0.01 count, while Salmonella enumeration and frequency significantly decreased in neck (p = 0.03 and tended to decrease in cecum (p = 0.06, feces (p = 0.06, and breast (p = 0.08. On 10d PI Campylobacter presence was decreased in cecum (p = 0.01, feces (p < 0.01, breast skin (p = 0.04 and neck skin (p < 0.01, while the enumeration was found to be lower in feces (p < 0.01 and neck skin (p = 0.05. At the end of the trial the frequency of this pathogen was decreased in feces (p < 0.01, and breast skin (p = 0.02, while the enumeration was diminished in cecum (p < 0.05 and feces (p < 0.05. Conclusions. The present study shows that the inclusion of Levucell® SB20 can significantly control Campylobacter carriage in chickens with some positive effects also on Salmonella presence, thus reducing the contamination of carcasses at slaughtering and preventing human foodborne diseases.

  4. Removal of lead, mercury and nickel using the yeast Saccharomyces cerevisiae / Remoción de plomo, mercurio y níquel utilizando la levadura Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Cherlys, Infante J; Deniles, De Arco R; Edgardo, Angulo M.

    2014-05-01

    Full Text Available Objetivos. En este estudio se utilizó la biomasa de la levadura Saccharomyces cerevisiae para retener plomo, mercurio y níquel en forma de iones disueltos en agua. Materiales y métodos. Se prepararon soluciones sintéticas que contenían los tres metales pesados, las cuales se pusieron en contacto con [...] el microorganismo en forma viable a diferentes condiciones de pH, temperatura, aireación y agitación. Resultados. Tanto las variables individuales como los efectos de interacción influyeron sobre el proceso de biosorción. A través de todos los experimentos, se observó que la biomasa de Saccharomyces cerevisiae eliminó un mayor porcentaje de plomo (86.4%) en comparación al mercurio y al níquel (69.7 y 47.8% respectivamente). Cuando el pH se fijó en valor de 5, el efecto fue positivo para los tres metales. Conclusiones. El pH fue la variable que tuvo una mayor influencia en la biosorción de plomo sobre la biomasa de Saccharomyces cerevisiae. La afinidad de los metales pesados por la biomasa siguió el orden Pb>Hg>Ni. Abstract in english Objective. In this study the biomass of the yeast Saccharomyces cerevisiae was used to remove lead, mercury and nickel in the form of ions dissolved in water. Materials and methods. Synthetic solutions were prepared containing the three heavy metals, which were put in contact with viable microorgani [...] sms at different conditions of pH, temperature, aeration and agitation. Results. Both individual variables and the interaction effects influenced the biosorption process. Throughout the experimental framework it was observed that the biomass of Saccharomyces cerevisiae removed a higher percentage of lead (86.4%) as compared to mercury and nickel (69.7 and 47.8% respectively). When the pH was set at a value of 5 the effect was positive for all three metals. Conclusions. pH was the variable that had a greater influence on the biosorption of lead on the biomass of Saccharomyces cerevisiae. The affinity of the heavy metals for the biomass followed the order Pb>Hg>Ni.

  5. Idebenone treatment mediates the effect of menadione oxidative stress damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Gamondi, Oliver; Chapela, Sebastián; Nievas, Inés; Burgos, Isabel; Alonso, Manuel; Stella, Carlos

    2012-06-01

    We investigated the damage caused by oxidative stress using the yeast Saccharomyces cerevisiae as a model biological system. After inducing oxidative stress with menadione, we were able to evaluate the extent of cellular oxidative stress by utilizing 2',7'-dichlorofluorescein diacetate (DCFH-DA) as a marker of the presence of reactive oxygen species. Cells were grown on different carbon sources in order to compare fermentative and oxidative metabolism. Under these conditions we evaluated the effectiveness of idebenone (2,3-dimethoxy-5-methyl-6-(10- hydroxydecyl)-1,4-benzoquinone) as a molecule that could relieve menadione-induced growth inhibition in Saccharomyces cerevisiae. PMID:22974201

  6. Characteristics of Saccharomyces cerevisiae yeasts exhibiting rough colonies and pseudohyphal morphology with respect to alcoholic fermentation

    OpenAIRE

    Reis, Vanda Renata; Bassi, Ana Paula Guarnieri; da Silva, Jessica Carolina Gomes; Ceccato-Antonini, Sandra Regina

    2014-01-01

    Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Ch...

  7. Effects of cyclohexane, an industrial solvent, on the yeast Saccharomyces cerevisiae and on isolated yeast mitochondria.

    OpenAIRE

    Uribe, S.; Rangel, P; Espínola, G; Aguirre, G.

    1990-01-01

    Little information on the effects of cyclohexane at the cellular or subcellular level is available. In Saccharomyces cerevisiae, cyclohexane inhibited respiration and diverse energy-dependent processes. In mitochondria isolated from S. cerevisiae, oxygen uptake and ATP synthesis were inhibited, although ATPase activity was not affected. Cyclohexane effects were similar to those reported for beta-pinene and limonene, suggesting that the cyclohexane ring in these monoterpenes may be a determina...

  8. Proteomic Evaluation of Cellular Responses of Saccharomyces cerevisiae to Formic Acid Stress

    OpenAIRE

    Lee, Sung-eun; Park, Byeoung-Soo; Yoon, Jeong-Jun

    2010-01-01

    Formic acid is a representative carboxylic acid that inhibits bacterial cell growth, and thus it is generally considered to constitute an obstacle to the reuse of renewable biomass. In this study, Saccharomyces cerevisiae was used to elucidate changes in protein levels in response to formic acid. Fifty-seven differentially expressed proteins in response to formic acid toxicity in S. cerevisiae were identified by 1D-PAGE and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) a...

  9. Transcriptional Responses of Saccharomyces cerevisiae to Shift from Respiratory and Respirofermentative to Fully Fermentative Metabolism

    OpenAIRE

    Rintala, Eija; Jouhten, Paula; Toivari, Mervi; Wiebe, Marilyn G.; Maaheimo, Hannu; Penttilä, Merja; Ruohonen, Laura

    2011-01-01

    In industrial fermentations of Saccharomyces cerevisiae, transient changes in oxygen concentration commonly occur and it is important to understand the behavior of cells during these changes. Glucose-limited chemostat cultivations were used to study the time-dependent effect of sudden oxygen depletion on the transcriptome of S. cerevisiae cells initially in fully aerobic or oxygen-limited conditions. The overall responses to anaerobic conditions of cells initially in different conditions were...

  10. Low oxygen levels as a trigger for enhancement of respiratory metabolism in Saccharomyces cerevisiae

    OpenAIRE

    Wiebe Marilyn G; Pitkänen Juha-Pekka; Toivari Mervi; Rintala Eija; Ruohonen Laura; Penttilä Merja

    2009-01-01

    Abstract Background The industrially important yeast Saccharomyces cerevisiae is able to grow both in the presence and absence of oxygen. However, the regulation of its metabolism in conditions of intermediate oxygen availability is not well characterised. We assessed the effect of oxygen provision on the transcriptome and proteome of S. cerevisiae in glucose-limited chemostat cultivations in anaerobic and aerobic conditions, and with three intermediate (0.5, 1.0 and 2.8% oxygen) levels of ox...

  11. A Candida albicans surface antigen mediating adhesion and autoaggregation in Saccharomyces cerevisiae.

    OpenAIRE

    Barki, M; Koltin, Y.; van Wetter, M; Rosenberg, M.

    1994-01-01

    In a previous study (M. Barki, Y. Koltin, M. Yanko, A. Tamarkin, and M. Rosenberg, J. Bacteriol. 175:5683-5689, 1993), a 3.3-kb DNA fragment from Candida albicans which confers adhesion and autoaggregation in Saccharomyces cerevisiae was isolated and partially characterized. In this report, evidence is presented that the adhesion-autoaggregation phenotype observed in S. cerevisiae cells transformed with the candidal DNA fragment is due to expression of a C. albicans surface antigen. Rabbit an...

  12. Saccharomyces cerevisiae Mus81-Mms4 is a catalytic, DNA structure-selective endonuclease

    OpenAIRE

    Ehmsen, Kirk Tevebaugh; Heyer, Wolf-Dietrich

    2008-01-01

    The DNA structure-selective endonuclease Mus81-Mms4/Eme1 is a context-specific recombination factor that supports DNA replication, but is not essential for DSB repair in Saccharomyces cerevisiae. We overexpressed Mus81-Mms4 in S. cerevisiae, purified the heterodimer to apparent homogeneity, and performed a classical enzymological characterization. Kinetic analysis (kcat, KM) demonstrated that Mus81-Mms4 is catalytically active and identified three substrate classes in vitro. Class I substrate...

  13. Functional co-operation between the nuclei of Saccharomyces cerevisiae and mitochondria from other yeast species

    DEFF Research Database (Denmark)

    Spirek, M.; Horvath, A.; Piskur, Jure; Sulo, P.

    2000-01-01

    We elaborated a simple method that allows the transfer of mitochondria from collection yeasts to Saccharomyces cerevisiae. Protoplasts prepared from different yeasts were fused to the protoplasts of the ade2-1, ura3-52, kar1-1, rho (0) strain of S. cerevisiae and were selected for respiring cybrids on plates containing 5-fluoroorotic acid and a non-fermentable carbon source. The identity of putative cybrids was assessed by restriction analysis of mitochondrial DNA, pulse field electrophoresis an...

  14. Physiological impact and context dependency of transcriptional responses: a chemostat study in Saccharomyces cerevisiae:

    OpenAIRE

    Tai, S.L.

    2007-01-01

    This thesis is a compilation of a four-year PhD project on bakers' yeast (Saccharomyces cerevisiae). Since the entire S. cerevisiae genome sequence became available in 1996, DNA-microarray analysis has become a popular high-information-density tool for analyzing gene expression in this important industrial microorganism and model eukaryote. This thesis explores chemostat-based analysis of the transcriptome (the complete set of messenger RNA molecules) as a tool to understand interaction of S....

  15. Continuous ethanol production from sugar beet thick juice by Saccharomyces cerevisiae immobilized onto sugar beet pulp

    OpenAIRE

    Vu?urovi? Vesna M.; Razmovski Radojka N.; Milji? Uroš D.; Puškaš Vladimir S.

    2013-01-01

    The immobilization of Saccharomyces cerevisiae onto sugar beet pulp (SBP) by natural adhesion is an efficient and low-cost method for retaining high biocatalyst density in the ethanol fermentation system. In the present study, cells of S. cerevisiae 163, were immobilized by natural adhesion onto SBP. The retention of immobilized cells attained the level of about 1.7×1011 cells/gram of dry SBP. Continuous ethanol production from sugar beet thick juice (TJ) w...

  16. Regulation of phospholipid synthesis in phosphatidylserine synthase-deficient (chol) mutants of Saccharomyces cerevisiae.

    OpenAIRE

    Letts, V.A.; Henry, S A

    1985-01-01

    chol mutants of Saccharomyces cerevisiae are deficient in the synthesis of the phospholipid phosphatidylserine owing to lowered activity of the membrane-associated enzyme phosphatidylserine synthase. chol mutants are auxotrophic for ethanolamine or choline and, in the absence of these supplements, cannot synthesize phosphatidylethanolamine or phosphatidylcholine (PC). We exploited these characteristics of the chol mutants to examine the regulation of phospholipid metabolism in S. cerevisiae. ...

  17. Analysis of the Metabolic Response of Saccharomyces Cerevisiae to DNA Damaging Agents

    OpenAIRE

    Rey, Simon Scheel

    2011-01-01

    Saccharomyces cerevisiae, commonly known as Baker?s yeast, is a eukaryotic model organism widely used in biotechnology research. Its genome has a high degree of similarity to humans, and research done on S. cerevisiae can give us a better understanding of the mechanisms involved and the cellular responses to anti-cancer drugs. Yeast is therefore usefool in increasing the effectiveness of anti-cancer drugs.The main goal for this master thesis was to investigate the metabolic response of S...

  18. Glutatation Transferasas de clase Omega en Saccharomyces cerevisiae: Estudio Bioquímico y Funcional

    OpenAIRE

    Barreto Parra, Lina Patricia

    2007-01-01

    Saccharomyces cerevisiae posseeix dues glutatió transferases (GST) anomenades Gtt1i Gtt2, amb capacitat de conjugar una molècula de glutatió amb el substrat estàndarCDNB. Aquests dos enzims no són clasificables dins de les classes convencionalsdescrites en base a l'estructura de les GST d'eucariotes superiors, encara que guardencerta similitud estructural amb els membres de la classe Zeta. En aquesta memòria esdescriu la caracterització de tres GST de classe Omega en S. cerevisiae anomenadesG...

  19. Rad52 multimerization is important for its nuclear localization in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Plate, Iben; Albertsen, Line; Lisby, Michael; Hallwyl, Swee Chuang Lim; Feng, Qi; Seong, Changhyun; Rothstein, Rodney; Sung, Patrick; Mortensen, Uffe Hasbro

    2008-01-01

    Rad52 is essential for all homologous recombination and DNA double strand break repair events in Saccharomyces cerevisiae. This protein is multifunctional and contains several domains that allow it to interact with DNA as well as with different repair proteins. However, it has been unclear how Rad52 enters the nucleus. In the present study, we have used a combination of mutagenesis and sequence analysis to show that Rad52 from S. cerevisiae contains a single functional pat7 type NLS essential fo...

  20. Optimization of maize starch fermentation by Saccharomyces cerevisiae using pervaporation / Sinethemba Aubrey Nongauza.

    OpenAIRE

    Nongauza, Sinethemba Aubrey

    2010-01-01

    Due to the depletion of petroleum reserves and environmental concerns, bioethanol has been identified as an alternative fuel to petrol. Bioethanol is a fuel of bio-origin derived from renewable biomass. Starch and sugar containing materials are the primary sources of carbon for bioethanol production. Starch is firstly hydrolysed into simple sugars which are later fermented to bioethanol using Saccharomyces cerevisiae (S. cerevisiae). The fermentation of sugars to bioethanol is however limited...

  1. Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth

    2014-01-01

    Biofilm-forming microorganisms switch between two forms: free-living planktonic and sessile multicellular. Sessile communities of yeast biofilms in liquid medium provide a primitive example of multicellularity and are clinically important because biofilms tend to have other growth characteristics than free-living cells. We investigated the genetic basis for yeast, Saccharomyces cerevisiae, biofilm on solid surfaces in liquid medium by screening a comprehensive deletion mutant collection in the S1278b background and found 71 genes that were essential for biofilm development. Quantitative northern blots further revealed that AIM1, ASG1, AVT1, DRN1, ELP4, FLO8, FMP10, HMT1, KAR5, MIT1, MRPL32, MSS11, NCP1, NPR1, PEP5, PEX25, RIM8, RIM101, RGT1, SNF8, SPC2, STB6, STP22, TEC1, VID24, VPS20, VTC3, YBL029W, YBL029C-A, YFL054C, YGR161W-C, YIL014C-A, YIR024C, YKL151C, YNL200C, YOR034C-A, and YOR223W controlled biofilm through FLO11 induction. Almost all deletion mutants that were unable to form biofilms in liquid medium also lost the ability to form surface-spreading biofilm colonies (mats) on agar and 69% also lost the ability to grow invasively. The protein kinase A isoform Tpk3p functioned specifically in biofilm and mat formation. In a tpk3 mutant, transcription of FLO11 was induced three-fold compared with wild-type, but biofilm development and cell–cell adhesion was absent, suggesting that Tpk3p regulates FLO11 positive posttranscriptionally and negative transcriptionally. The study provides a resource of biofilm-influencing genes for additional research on biofilm development and suggests that the regulation of FLO11 is more complex than previously anticipated.

  2. [Construction of Saccharomyces cerevisiae cell factories for lycopene production].

    Science.gov (United States)

    Shi, Ming-Yu; Liu Yi; Wang, Dong; Lu, Fu-Ping; Huang, Lu-Qi; Dai, Zhu-Bo; Zhang, Xue-Li

    2014-10-01

    For microbial production of lycopene, the lycopene synthetic genes from Pantoea agglomerans were integrated into Saccharomyces cerevisiae strain BY4742, to obtain strain ZD-L-000 for production of 0.17 mg · L(-1) lycopene. Improving supplies of isoprenoid precursors was then investigated for increasing lycopene production. Four key genes were chosen to be overexpressed, inclu- ding truncated 3-hydroxy-3-methylglutaryl-CoA reductase gene (tHMG1), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, a mutated global regulatory factor gene (upc2.1), a fusion gene of FPP synthase (ERG20) and endogenous GGPP synthase (BTS1), which is a key enzyme in the diterpenoid synthetic pathway, and GGPP synthase gene (SaGGPS) from Sulfolobus acidocaldarius. Over-expression of upc2.1 could not improve lycopene production, while over-expression of tHMGI , BTS1-ERG20 and SaGGPS genes led to 2-, 16. 9- and20. 5-fold increase of lycopene production, respectively. In addition, three effective genes, tHMG1, BTS1-ERG20 and SaGGPS, were integrated into rDNA sites of ZD-L-000, resulting in strain ZD-L-201 for production of 13.23 mg · L(-1) lycopene, which was 77-fold higher than that of the parent strain. Finally, two-phase extractive fermentation was performed. The titer of lycopene increased 10-fold to 135.21 mg · L(-1). The engineered yeast strains obtained in this work provided the basis for fermentative production of lycopene. PMID:25751950

  3. Genetic basis of arsenite and cadmium tolerance in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Dawes Ian W

    2009-03-01

    Full Text Available Abstract Background Arsenic and cadmium are widely distributed in nature and pose serious threats to the environment and human health. Exposure to these nonessential toxic metals may result in a variety of human diseases including cancer. However, arsenic and cadmium toxicity targets and the cellular systems contributing to tolerance acquisition are not fully known. Results To gain insight into metal action and cellular tolerance mechanisms, we carried out genome-wide screening of the Saccharomyces cerevisiae haploid and homozygous diploid deletion mutant collections and scored for reduced growth in the presence of arsenite or cadmium. Processes found to be required for tolerance to both metals included sulphur and glutathione biosynthesis, environmental sensing, mRNA synthesis and transcription, and vacuolar/endosomal transport and sorting. We also identified metal-specific defence processes. Arsenite-specific defence functions were related to cell cycle regulation, lipid and fatty acid metabolism, mitochondrial biogenesis, and the cytoskeleton whereas cadmium-specific defence functions were mainly related to sugar/carbohydrate metabolism, and metal-ion homeostasis and transport. Molecular evidence indicated that the cytoskeleton is targeted by arsenite and that phosphorylation of the Snf1p kinase is required for cadmium tolerance. Conclusion This study has pin-pointed core functions that protect cells from arsenite and cadmium toxicity. It also emphasizes the existence of both common and specific defence systems. Since many of the yeast genes that confer tolerance to these agents have homologues in humans, similar biological processes may act in yeast and humans to prevent metal toxicity and carcinogenesis.

  4. Metabolic engineering of Saccharomyces cerevisiae for optimizing 3HP production

    DEFF Research Database (Denmark)

    Jensen, Niels Bjerg; Maury, Jerome

    2012-01-01

    The finite nature of fossil resources and the negative influence of CO2 emissions on the global climate are key drivers in development of new biological processes. These are based on renewable resources such as sugar, starch, and biomass and aim at replacing chemical production from fossil fuels. Polyacrylates are a substantial part of the different plastic varieties found on the market. This kind of plastic is derived from acrylic acid, which is currently produced from propylene, a by-product of ethylene and gasoline production. Annually, more than one billion kilograms of acrylic acid is produced and the market for acrylate products exceeds USD 100 billion. As an alternative to oil and gas derived acrylic acid, 3-hydroxypropionic (3HP) acid produced from renewable sources is highly desired, because 3HP can easily be converted into acrylic acid. We are setting out to produce 3HP in yeast Saccharomyces cerevisiae. One main reason for selecting Baker's yeast as host organism is that yeast has a high tolerance towards low pH in comparison to bacteria, e.g. E. coli. Hence, it lowers the consumption of base for neutralization of growth media when compared to bacteria. The preferred engineered pathway towards 3HP has a substantial need for NADPH equivalents. Consequently, a yeast host with elevated NADPH availability is preferred. We will redirect several of the glycolysis steps in order to increase the NADPH generation per glucose molecule and thereby increase 3HP production. We believe this strain will be of high interest for other NADPH demanding biosynthetic routes.

  5. IMMOBILIZATION OF Saccharomyces cerevisiae IN RICE HULLS FOR ETHANOL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Don-Hee Park

    2010-11-01

    Full Text Available The whole cell immobilization in ethanol fermentation can be done by using natural carriers or through synthetic carriers. All of these methods have the same purpose of retaining high cell concentrations within a certain defined region of space which leads to higher ethanol productivity. Lignocellulosic plant substance represents one of highly potential sources in ethanol production. Some studies have found that cellulosic substances substances can also be used as a natural carrier in cell immobilization by re-circulating pre-culture medium into a reactor. In this experiment, rice hulls without any treatment were used to immobilize Saccharomyces cerevisiae through semi solid state incubation combined with re-circulating pre-culture medium. The scanning electron microscopy (SEM pictures of the carrier show that the yeast cells are absorbed and embedded to the rice hull pore. In liquid batch fermentation system with an initial sugar concentration of 50 g/L, nearly 100% total sugar was consumed after 48 hours. This resulted in an ethanol yield of 0.32 g ethanol/g glucose, which is 62.7% of the theoretical value. Ethanol productivity of 0.59 g/(L.h is 2.3 fold higher than that of free cells which is 0.26 g/(L.h. An effort to reuse the immobilized cells in liquid fermentation system showed poor results due to cell desorption in the first batch which led to high sugar concentration inhibitory effect in the second batch fermentation. This might be solved by using semi solid fermentation process in the future work.

  6. Mutational analysis reveals a role for the C terminus of the proteasome subunit Rpt4p in spindle pole body duplication in Saccharomyces cerevisiae.

    OpenAIRE

    McDonald, Heather B.; Helfant, Astrid Hoes; Mahony, Erin M; Khosla, Shaun K; Goetsch, Loretta

    2002-01-01

    The ubiquitin/proteasome pathway plays a key role in regulating cell cycle progression. Previously, we reported that a conditional mutation in the Saccharomyces cerevisiae gene RPT4/PCS1, which encodes one of six ATPases in the proteasome 19S cap complex/regulatory particle (RP), causes failure of spindle pole body (SPB) duplication. To improve our understanding of Rpt4p, we created 58 new mutations, 53 of which convert clustered, charged residues to alanine. Virtually all mutations that affe...

  7. Functional Characterization of an ?-Factor-Like Sordaria macrospora Peptide Pheromone and Analysis of Its Interaction with Its Cognate Receptor in Saccharomyces cerevisiae

    OpenAIRE

    Mayrhofer, Severine; Pöggeler, Stefanie

    2005-01-01

    The homothallic filamentous ascomycete Sordaria macrospora possesses genes which are thought to encode two pheromone precursors and two seven-transmembrane pheromone receptors. The pheromone precursor genes are termed ppg1 and ppg2. The putative products derived from the gene sequence show structural similarity to the ?-factor precursors and a-factor precursors of the yeast Saccharomyces cerevisiae. Likewise, sequence similarity has been found between the putative products of the pheromone re...

  8. The HOG pathway controls osmotic regulation of transcription via the stress response element (STRE) of the Saccharomyces cerevisiae CTT1 gene.

    OpenAIRE

    Schüller, C.; Brewster, J L; Alexander, M. R.; Gustin, M C; Ruis, H.

    1994-01-01

    The HOG signal pathway of the yeast Saccharomyces cerevisiae is defined by the PBS2 and HOG1 genes encoding members of the MAP kinase kinase and of the MAP kinase family, respectively. Mutations in this pathway (deletions of PBS2 or HOG1, or point mutations in HOG1) almost completely abolish the induction of transcription by osmotic stress that is mediated by stress response elements (STREs). We have demonstrated previously that STREs also mediate induction of transcription by heat shock, nit...

  9. Effect of intron mutations on processing and function of Saccharomyces cerevisiae SUP53 tRNA in vitro and in vivo.

    OpenAIRE

    Strobel, M C; Abelson, J.

    1986-01-01

    The Saccharomyces cerevisiae leucine-inserting amber suppressor tRNA gene SUP53 (a tRNALeu3 allele) was used to investigate the relationship between precursor tRNA structure and mature tRNA function. This gene encodes a pre-tRNA which contains a 32-base intron. The mature tRNASUP53 contains a 5-methylcytosine modification of the anticodon wobble base. Mutations were made in the SUP53 intron. These mutant genes were transcribed in an S. cerevisiae nuclear extract preparation. In this extract, ...

  10. Accumulation and chemical states of radiocesium by fungus Saccharomyces cerevisiae

    Science.gov (United States)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya; Yu, Qianqian

    2014-05-01

    After accident of Fukushima Daiichi Nuclear Power Plant, the fall-out radiocesium was deposited on the ground. Filamentous fungus is known to accumulate radiocesium in environment, even though many minerals are involved in soil. These facts suggest that fungus affect the migration behavior of radiocesium in the environment. However, accumulation mechanism of radiocesium by fungus is not understood. In the present study, accumulation and chemical states change of Cs by unicellular fungus of Saccharomyces cerevisiae have been studied to elucidate the role of microorganisms in the migration of radiocesium in the environment. Two different experimental conditions were employed; one is the accumulation experiments of radiocesium by S. cerevisiae from the agar medium containing 137Cs and a mineral of zeolite, vermiculite, smectite, mica, or illite. The other is the experiments using stable cesium to examine the chemical states change of Cs. In the former experiment, the cells were grown on membrane filter of 0.45 ?m installed on the agar medium. After the grown cells were weighed, radioactivity in the cells was measured by an autoradiography technique. The mineral weight contents were changed from 0.1% to 1% of the medium. In the latter experiment, the cells were grown in the medium containing stable Cs between 1 mM and 10mM. The Cs accumulated cells were analyzed by SEM-EDS and EXAFS. The adsorption experiments of cesium by the cells under resting condition were also conducted to test the effect of cells metabolic activity. Without mineral in the medium, cells of S. cerevisiae accumulated 1.5x103 Bq/g from the medium containing 137Cs of 2.6x102 Bq/g. When mineral was added in the medium, concentration of 137Cs in the cells decreased. The concentration of 137Cs in the cells from the medium containing different minerals were in the following order; smectite, illite, mica > vermiculite > zeolite. This order was nearly the same as the inverse of distribution coefficient of mineral for 137Cs in the medium solution. The concentration of 137Cs in the cells lowered in the medium containing higher mineral content. These results indicate that radiocesium was competively accumulated in the cells with minerals in the soil. Higher concentration of stable Cs was accumulated in the cells in the metabolically active condition than in the resting cells condition. XAFS analyses showed that the k3-weighted extended-XAFS functions and the radial structural function of Cs accumulated by the cells in the metabolically active condition were similar to those in the resting condition, indicating that chemical states of the accumulated Cs were nearly the same between both conditions. These results indicate that the fungus accumulates radiocesium by competitively with minerals in the soils, and performs higher retardation of the migration of Cs in the metabolically active condition than the resting one. A part of this study is the results of "Multidisciplinary investigation on radiocesium fate and transport for safety assessment for interim storage and disposal of heterogeneous waste" carried out under the Initiatives for Atomic Energy Basic and Generic Strategic Research by the Ministry of Education, Culture, Sports, Science and Technology of Japan.

  11. Functional Analysis of Free Methionine-R-sulfoxide Reductase from Saccharomyces cerevisiae*S?

    Science.gov (United States)

    Le, Dung Tien; Lee, Byung Cheon; Marino, Stefano M.; Zhang, Yan; Fomenko, Dmitri E.; Kaya, Alaattin; Hacioglu, Elise; Kwak, Geun-Hee; Koc, Ahmet; Kim, Hwa-Young; Gladyshev, Vadim N.

    2009-01-01

    Methionine sulfoxide reductases (Msrs) are oxidoreductases that catalyze thiol-dependent reduction of oxidized methionines. MsrA and MsrB are the best known Msrs that repair methionine-S-sulfoxide (Met-S-SO) and methionine-R-sulfoxide (Met-R-SO) residues in proteins, respectively. In addition, an Escherichia coli enzyme specific for free Met-R-SO, designated fRMsr, was recently discovered. In this work, we carried out comparative genomic and experimental analyses to examine occurrence, evolution, and function of fRMsr. This protein is present in single copies and two mutually exclusive subtypes in about half of prokaryotes and unicellular eukaryotes but is missing in higher plants and animals. A Saccharomyces cerevisiae fRMsr homolog was found to reduce free Met-R-SO but not free Met-S-SO or dabsyl-Met-R-SO. fRMsr was responsible for growth of yeast cells on Met-R-SO, and the double fRMsr/MsrA mutant could not grow on a mixture of methionine sulfoxides. However, in the presence of methionine, even the triple fRMsr/MsrA/MsrB mutant was viable. In addition, fRMsr deletion strain showed an increased sensitivity to oxidative stress and a decreased life span, whereas overexpression of fRMsr conferred higher resistance to oxidants. Molecular modeling and cysteine residue targeting by thioredoxin pointed to Cys101 as catalytic and Cys125 as resolving residues in yeast fRMsr. These residues as well as a third Cys, resolving Cys91, clustered in the structure, and each was required for the catalytic activity of the enzyme. The data show that fRMsr is the main enzyme responsible for the reduction of free Met-R-SO in S. cerevisiae. PMID:19049972

  12. Antibodies anti-Saccharomyces cerevisiae (ASCA do not differentiate Crohn's disease from celiac disease Anticorpos anti-Saccharomyces cerevisiae não diferenciam doença de Crohn de doença celíaca

    Directory of Open Access Journals (Sweden)

    Lorete Maria da Silva Kotze

    2010-09-01

    Full Text Available CONTEXT: Anti-Saccharomyces cerevisiae antibodies (ASCA, considered serologic markers for Crohn's disease, were described in patients with celiac disease, disappearing after a gluten-free diet. OBJECTIVES: Evaluation of ASCA positivity in patients with Crohn's disease and celiac disease in relation to healthy individuals. METHODS: A total of 145 individuals were studied: 36 with Crohn's disease and 52 with celiac disease, that fulfilled the diagnostic criteria for both affections, and 57 healthy individuals for control. The celiac patients were divided as follow: group CeD I at diagnosis (n = 34, group CeD II with gluten-free diet compliance (n = 13 and group CeD III with transgressions to the diet (n = 5. ASCA IgA and IgG were determined by ELISA. RESULTS: With statistical significance, ASCA IgA were positive in Crohn's disease, celiac disease at diagnosis and celiac disease with diet transgressions; ASCA IgG in Crohn's disease and in all groups with celiac disease. CONCLUSIONS: The detection of ASCA in patients with celiac disease allows to suggest that ASCA is not a specific marker for Crohn's disease, but was associated with the inflammation of the small intestine. The increased levels of positive ASCA may be due to genetic factors and increased intestinal permeability.RACIONAL: Anticorpos anti-Saccharomyces cerevisiae antibodies, considerados marcadores sorológicos para a doença de Crohn, foram descritos em pacientes com doença celíaca, desaparecendo após dieta isenta de glúten. OBJETIVOS: Avaliação da positividade de anti-Saccharomyces cerevisiae antibodies em pacientes com doença de Crohn e doença celíaca, em relação a indivíduos sadios da mesma área geográfica. MÉTODOS: Foram estudados 145 pacientes, 36 com doença de Crohn e 52 com doença celíaca que preencheram os critérios diagnósticos para ambas as afecções, e 57 indivíduos sadios para controle. Os pacientes celíacos foram divididos como segue: ao diagnóstico (grupo doença celíaca I: n = 34, obedientes à dieta isenta de glúten (grupo doença celíaca II: n = 13 e não-aderentes à dieta isenta de glúten (grupo doença celíaca III: n = 5. Anti-Saccharomyces cerevisiae antibodies IgA e IgG foram determinados por ELISA. RESULTADOS: Anti-Saccharomyces cerevisiae antibodies IgA foi positivo na doença de Crohn, nos celíacos ao diagnóstico e nos transgressores à dieta, com significado estatístico. Anti-Saccharomyces cerevisiae antibodies IgG foi positivo na doença de Crohn e em todos os grupos de celíacos, com significado estatístico. CONCLUSÕES: A detecção de anti-Saccharomyces cerevisiae antibodies em pacientes com doença celíaca permite sugerir que o mesmo não seja marcador específico para a doença de Crohn, mas que esteja associado à inflamação do intestino delgado. A positividade de anti-Saccharomyces cerevisiae antibodies pode ser decorrente de fatores genéticos e aumento da permeabilidade intestinal.

  13. Antibodies anti-Saccharomyces cerevisiae (ASCA) do not differentiate Crohn's disease from celiac disease / Anticorpos anti-Saccharomyces cerevisiae não diferenciam doença de Crohn de doença celíaca

    Scientific Electronic Library Online (English)

    Lorete Maria da Silva, Kotze; Renato Mitsunori, Nisihara; Shirley Ramos da Rosa, Utiyama; Paulo Gustavo, Kotze; Petra Mirella, Theiss; Márcia, Olandoski.

    2010-09-01

    Full Text Available RACIONAL: Anticorpos anti-Saccharomyces cerevisiae antibodies, considerados marcadores sorológicos para a doença de Crohn, foram descritos em pacientes com doença celíaca, desaparecendo após dieta isenta de glúten. OBJETIVOS: Avaliação da positividade de anti-Saccharomyces cerevisiae antibodies em p [...] acientes com doença de Crohn e doença celíaca, em relação a indivíduos sadios da mesma área geográfica. MÉTODOS: Foram estudados 145 pacientes, 36 com doença de Crohn e 52 com doença celíaca que preencheram os critérios diagnósticos para ambas as afecções, e 57 indivíduos sadios para controle. Os pacientes celíacos foram divididos como segue: ao diagnóstico (grupo doença celíaca I: n = 34), obedientes à dieta isenta de glúten (grupo doença celíaca II: n = 13) e não-aderentes à dieta isenta de glúten (grupo doença celíaca III: n = 5). Anti-Saccharomyces cerevisiae antibodies IgA e IgG foram determinados por ELISA. RESULTADOS: Anti-Saccharomyces cerevisiae antibodies IgA foi positivo na doença de Crohn, nos celíacos ao diagnóstico e nos transgressores à dieta, com significado estatístico. Anti-Saccharomyces cerevisiae antibodies IgG foi positivo na doença de Crohn e em todos os grupos de celíacos, com significado estatístico. CONCLUSÕES: A detecção de anti-Saccharomyces cerevisiae antibodies em pacientes com doença celíaca permite sugerir que o mesmo não seja marcador específico para a doença de Crohn, mas que esteja associado à inflamação do intestino delgado. A positividade de anti-Saccharomyces cerevisiae antibodies pode ser decorrente de fatores genéticos e aumento da permeabilidade intestinal. Abstract in english CONTEXT: Anti-Saccharomyces cerevisiae antibodies (ASCA), considered serologic markers for Crohn's disease, were described in patients with celiac disease, disappearing after a gluten-free diet. OBJECTIVES: Evaluation of ASCA positivity in patients with Crohn's disease and celiac disease in relation [...] to healthy individuals. METHODS: A total of 145 individuals were studied: 36 with Crohn's disease and 52 with celiac disease, that fulfilled the diagnostic criteria for both affections, and 57 healthy individuals for control. The celiac patients were divided as follow: group CeD I at diagnosis (n = 34), group CeD II with gluten-free diet compliance (n = 13) and group CeD III with transgressions to the diet (n = 5). ASCA IgA and IgG were determined by ELISA. RESULTS: With statistical significance, ASCA IgA were positive in Crohn's disease, celiac disease at diagnosis and celiac disease with diet transgressions; ASCA IgG in Crohn's disease and in all groups with celiac disease. CONCLUSIONS: The detection of ASCA in patients with celiac disease allows to suggest that ASCA is not a specific marker for Crohn's disease, but was associated with the inflammation of the small intestine. The increased levels of positive ASCA may be due to genetic factors and increased intestinal permeability.

  14. Saccharomyces kudriavzevii and Saccharomyces uvarum differ from Saccharomyces cerevisiae during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors.

    Science.gov (United States)

    Stribny, Jiri; Gamero, Amparo; Pérez-Torrado, Roberto; Querol, Amparo

    2015-07-16

    Higher alcohols and acetate esters are important flavour and aroma components in the food industry. In alcoholic beverages these compounds are produced by yeast during fermentation. Although Saccharomyces cerevisiae is one of the most extensively used species, other species of the Saccharomyces genus have become common in fermentation processes. This study analyses and compares the production of higher alcohols and acetate esters from their amino acidic precursors in three Saccharomyces species: Saccharomyces kudriavzevii, Saccharomyces uvarum and S. cerevisiae. The global volatile compound analysis revealed that S. kudriavzevii produced large amounts of higher alcohols, whereas S. uvarum excelled in the production of acetate esters. Particularly from phenylalanine, S. uvarum produced the largest amounts of 2-phenylethyl acetate, while S. kudriavzevii obtained the greatest 2-phenylethanol formation from this precursor. The present data indicate differences in the amino acid metabolism and subsequent production of flavour-active higher alcohols and acetate esters among the closely related Saccharomyces species. This knowledge will prove useful for developing new enhanced processes in fragrance, flavour, and food industries. PMID:25886016

  15. Growth and fermentation characteristics of Saccharomyces cerevisiae NK28 isolated from kiwi fruit.

    Science.gov (United States)

    Lee, Jong-Sub; Park, Eun-Hee; Kim, Jung-Wan; Yeo, Soo-Hwan; Kim, Myoung-Dong

    2013-09-28

    The influences of glucose concentration, initial medium acidity (pH), and temperature on the growth and ethanol production of Saccharomyces cerevisiae NK28, which was isolated from kiwi fruit, were examined in shake flask cultures. The optimal glucose concentration, initial medium pH, and temperature for ethanol production were 200 g/l, pH 6.0, and 35oC, respectively. Under this growth condition, S. cerevisiae NK28 produced 98.9 ± 5.67 g/l ethanol in 24 h with a volumetric ethanol production rate of 4.12 ± 0.24 g/l·h. S. cerevisiae NK28 was more tolerant to heat and ethanol than laboratory strain S. cerevisiae BY4742, and its tolerance to ethanol and fermentation inhibitors was comparable to that of an ethanologen, S. cerevisiae D5A. PMID:23893096

  16. Viabilidade celular de Saccharomyces cerevisiae cultivada em associação com bactérias contaminantes da fermentação alcoólica / Cellular viability of Saccharomyces cerevisiae cultivated in association with contaminant bacteria of alcoholic fermentation

    Scientific Electronic Library Online (English)

    Thais de Paula, Nobre; Jorge, Horii; André Ricardo, Alcarde.

    2007-03-01

    Full Text Available O objetivo deste trabalho foi estudar a influência de bactérias dos gêneros Bacillus e Lactobacillus, bem como de seus produtos metabólicos, na redução da viabilidade celular de leveduras Saccharomyces cerevisiae. As bactérias Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lacto [...] bacillus fermentum e Lactobacillus plantarum foram cultivadas em associação com a levedura S. cerevisiae (cepa Y-904) por 72 horas a 32 °C, sob agitação. A viabilidade celular, a taxa de brotamento e a população de células de S. cerevisiae e a acidez total, a acidez volátil e o pH dos meios de cultivos foram determinados às 0, 24, 48 e 72 horas do cultivo misto. As culturas de bactérias foram tratadas através do calor, de agente antimicrobiano e de irradiação. Os resultados mostraram que apenas os meios de cultivo mais acidificados, contaminados com as bactérias ativas L. fermentum e B. subtilis, provocaram redução na viabilidade celular de S. cerevisiae. Excetuando a bactéria B. subtilis tratada com radiação gama, as demais bactérias tratadas pelos diferentes processos (calor, irradiação e antimicrobiano) não causaram diminuição da viabilidade celular e da população de S. cerevisiae, indicando que a presença isolada dos metabólitos celulares dessas bactérias não foi suficiente para reduzir a porcentagem de células vivas de S. cerevisiae. Abstract in english The aim of this project was to study the influence of the bacteria Bacillus and Lactobacillus, as well as their metabolic products to decrease the cellular viability of the yeast Saccharomyces cerevisiae. The bacteria Bacillus subtilis, Bacillus coagulans, Bacillus stearothermophilus, Lactobacillus [...] fermentum and Lactobacillus plantarum were cultivated in association with yeast S. cerevisiae (strain Y-904) for 72 hours at 32 ºC under agitation. The cellular viability, budding rate and population of S. Cerevisiae and the total acidity, volatile acidity and pH of culture medium were determined at 0, 24, 48 and 72 hours of incubation of the mixed culture. The bacteria cultures were treated by heat sterilization, antibacterial agent and irradiation. The results showed that only the more acidified culture medium, contaminated with active bacteria L. fermentum and B. subtilis, caused a reduction in the yeast cellular viability. Except for the bacteria B. subtilis treated for radiation, the other bacteria treated by the different procedures (heat, radiation and antibacterial) did not cause a reduction in the cellular viability of S. cerevisiae, indicating that the isolated presence of the cellular metabolic of these bacteria was not enough to reduce the percentage of the living yeast cells.

  17. Implementation of Sliding Mode Controller with Boundary Layer for Saccharomyces cerevisiae Fed-batch Cultivation

    Directory of Open Access Journals (Sweden)

    Stoyan Tzonkov

    2005-04-01

    Full Text Available An implementation of sliding mode control for yeast fed-batch cultivation is presented in this paper. Developed controller has been implemented on two real fed-batch cultivations of Saccharomyces cerevisiae. The controller successfully stabilizes the process and shows a very good performance at high input disturbances.

  18. Young cells of Saccharomyces cerevisiae with oncogenic mutation show features of aging.

    Czech Academy of Sciences Publication Activity Database

    Pichová, Alena; Sigler, Karel

    Dorchester : Wiley, 2007, s. 124-124. [International Conference on Yeast Genetics and Molecular Biology /23./. Melbourne (AU), 01.07.2007-06.07.2007] R&D Projects: GA ?R GA301/03/0289; GA ?R GA301/07/0339 Institutional research plan: CEZ:AV0Z50200510 Keywords : Saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  19. Identification of novel functional domains of Rad52 in Saccharomyces cerevisiae

    OpenAIRE

    Plate, Iben

    2006-01-01

    Reparation af DNA dobbeltstrengsbrud (DSB) er vigtig for opretholdelse af genetisk stabilitet. Manglende eller fejlagtig reparation af DNA DSB medfører genetisk ustabilitet, hvilket i højere eukaryoter kan føre til kræftudvikling. DNA DSB repareres blandt andet ved hjælp af homolog rekombination, som er den foretrukne reparationsmekanisme i bagegæren Saccharomyces cerevisiae, som derfor ofte anvendes som modelorganisme til at studere homolog rekombination. Reparationsvejen homolog rekombinati...

  20. Functional States Recognition System for Fed-batch Cultivation of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Pencheva T.

    2008-12-01

    Full Text Available Free software for entering and documenting data EpiData is here used for design of a system for functional states recognition during a fermentation process. The identification of the current process state is based on the predetermined rules, rendering specific metabolic mechanisms. Developed system is further applied for a fed-batch cultivation of Saccharomyces cerevisiae.

  1. Functional States Recognition System for Fed-batch Cultivation of Saccharomyces cerevisiae

    OpenAIRE

    Pencheva T.; Ljakova K.

    2008-01-01

    Free software for entering and documenting data EpiData is here used for design of a system for functional states recognition during a fermentation process. The identification of the current process state is based on the predetermined rules, rendering specific metabolic mechanisms. Developed system is further applied for a fed-batch cultivation of Saccharomyces cerevisiae.

  2. Searching for a nuclear transportin of the chromatin-remodeling factor ISW1 in Saccharomyces cerevisiae.

    Czech Academy of Sciences Publication Activity Database

    Strádalová, Vendula; Hašek, Ji?í; Janatová, Ivana

    2004, s. 100. [Symposium of the Society for Histochemistry /46./. Prague (CZ), 22.09.2004-25.09.2004] R&D Projects: GA AV ?R IAA5020409; GA AV ?R IAA5020102 Institutional research plan: CEZ:AV0Z5020903 Keywords : saccharomyces cerevisiae * isw1p Subject RIV: EE - Microbiology, Virology

  3. Saccharomyces cerevisiae BY4741 and W303-1A laboratory strains differ in salt tolerance.

    Czech Academy of Sciences Publication Activity Database

    Petrezsélyová, Silvia; Zahrádka, Jaromír; Sychrová, Hana

    2010-01-01

    Ro?. 114, 2-3 (2010), s. 144-150. ISSN 1878-6146 R&D Projects: GA MŠk(CZ) LC531; GA ?R(CZ) GA204/08/0354 Institutional research plan: CEZ:AV0Z50110509 Keywords : Saccharomyces cerevisiae * salt tolerance * potassium homeostasis Subject RIV: EB - Genetics ; Molecular Biology

  4. Effects of low-frequency magnetic fields on the viability of yeast Saccharomyces cerevisiae.

    Czech Academy of Sciences Publication Activity Database

    Novák, Jan; Strašák, Lud?k; Fojt, Lukáš; Slaninová, I.; Vetterl, Vladimír

    2007-01-01

    Ro?. 70, ?. 1 (2007), s. 115-121. ISSN 1567-5394 R&D Projects: GA AV ?R(CZ) IAA4004404; GA AV ?R(CZ) IBS5004107 Institutional research plan: CEZ:AV0Z50040702 Keywords : low-frequency electromagnetic field * yeast * Saccharomyces cerevisiae Subject RIV: BO - Biophysics Impact factor: 2.992, year: 2007

  5. Engineering Saccharomyces cerevisiae to produce feruloyl esterase for the release of ferulic acid from switchgrass

    Science.gov (United States)

    The Aspergillus niger ferulic acid esterase gene (faeA) was cloned into Saccharomyces cerevisiae via a yeast expression vector, resulting in efficient expression and secretion of the enzyme in the medium. The recombinant enzyme was purified to homogeneity by anion-exchange and hydrophobic interactio...

  6. Long-term developmernt of Saccharomyces cerevisiae colonies: Chaugs in stress factors.

    Czech Academy of Sciences Publication Activity Database

    Váchová, Libuše; Devaux, F.; Ku?erová, Helena; ?i?icová, M.; Palková, Z.

    Sweden, 2003, s. 197. [International Conference on Yeast Genetics and Molecular Biology /11./. Goteborg (SE), 07.07.2003-12.07.2003] R&D Projects: GA ?R GA204/02/0650 Institutional research plan: CEZ:MSM 113100003 Keywords : saccharomyces * cerevisiae * colonies Subject RIV: EE - Microbiology, Virology

  7. Screening and identification of respiration deficiency mutants of yeasts (Saccharomyces Cerevisiae) induced by heavy ion irradiation

    International Nuclear Information System (INIS)

    A screen of respiration deficiency mutants of Saccharomyces Cerevisiae induced by 5.19 MeV/u 22Ne5- ion irradiation is studied. Some respiration deficiency mutants, which are white colony phenotype in the selective culture of TTC medium, are obtained. The mutants are effectively identified by means of a new and simplified restriction analysis method. (authors)

  8. Aged mother cells of Saccharomyces cerevisiae show markers of oxidative stress and apoptosis.

    Czech Academy of Sciences Publication Activity Database

    Laun, P.; Pichová, Alena; Madeo, F.; Fuchs, J.; Ellinger, A.; Kohlwein, S.; Dawes, I.; Fröhlich, K. U.; Breitenbach, M.

    2001-01-01

    Ro?. 39, ?. 5 (2001), s. 1166-1173. ISSN 0950-382X R&D Projects: GA ?R GA204/97/0541 Institutional research plan: CEZ:AV0Z5020903 Keywords : Saccharomyces cerevisiae * genetic changes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.398, year: 2001

  9. The uptake of different iron salts by the yeast Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Fernanda, Gaensly; Geraldo, Picheth; Debora, Brand; Tania M.B., Bonfim.

    2014-06-01

    Full Text Available Yeasts can be enriched with microelements, including iron; however, special physicochemical conditions are required to formulate a culture media that promotes both yeast growth and iron uptake. Different iron sources do not affect biomass formation; however, considering efficacy, cost, stability, an [...] d compatibility with Saccharomyces cerevisiae metabolism, ferrous sulphate is recommended.

  10. Degradation of Specific Nuclear Proteins Occurs in the Cytoplasm in Saccharomyces cerevisiae

    OpenAIRE

    Chen, Li; Madura, Kiran

    2014-01-01

    The ubiquitin/proteasome system has been characterized extensively, although the site of nuclear substrate turnover has not been established definitively. We report here that two well-characterized nuclear proteins are stabilized in nuclear export mutants in Saccharomyces cerevisiae. The requirement for nuclear export defines a new regulatory step in intracellular proteolysis.

  11. Studies on the effect of virous of facts on biosorption of uranium by saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The biosorption of uranium from solution by saccharomyces cerevisiae was studied. The effect of pH and the different initial concentration has been examined. The model of biosorption has been proved in agreement with langmuir and Freundlich model by the connection of uranium equilibrium concentration and uptake. Results indicate that the maximum uptake can reach 196.1 mg/g

  12. Lipid Raft-Based Membrane Compartmentation of a Plant Transport Protein Expressed in Saccharomyces cerevisiae.

    Czech Academy of Sciences Publication Activity Database

    Grossmann, Q.; Opekarová, Miroslava; Nováková, L.; Stolz, J.; Tanner, W.

    2006-01-01

    Ro?. 5, ?. 6 (2006), s. 945-953. ISSN 1535-9778 R&D Projects: GA MŠk LC545 Institutional research plan: CEZ:AV0Z50200510 Keywords : saccharomyces cerevisiae * plant transport protein * hup1 Subject RIV: EE - Microbiology, Virology Impact factor: 3.707, year: 2006

  13. Production of miltiradiene by metabolically engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Dai, Zhubo; Liu, Yi; Huang, Luqi; Zhang, Xueli

    2012-11-01

    Metabolic engineering of microorganisms is an alternative and attractive route for production of valuable terpenoids that are usually extracted from plant sources. Tanshinones are the bioactive components of Salvia miltiorrhizha Bunge, which is a well-known traditional Chinese medicine widely used for treatment of many cardiovascular diseases. As a step toward microbial production of tanshinones, copalyl diphosphate (CPP) synthase, and normal CPP kaurene synthase-like genes, which convert the universal diterpenoid precursor geranylgeranyl diphosphate (GGPP) to miltiradiene (an important intermediate of the tanshinones synthetic pathway), was introduced into Saccharomyces cerevisiae, resulting in production of 4.2?mg/L miltiradiene. Improving supplies of isoprenoid precursors was then investigated for increasing miltiradiene production. Although over-expression of a truncated 3-hydroxyl-3-methylglutaryl-CoA reductase (tHMGR) and a mutated global regulatory factor (upc2.1) gene did improve supply of farnesyl diphosphate (FPP), production of miltiradiene was not increased while large amounts of squalene (78?mg/L) were accumulated. In contrast, miltiradiene production increased to 8.8?mg/L by improving supply of GGPP through over-expression of a fusion gene of FPP synthase (ERG20) and endogenous GGPP synthase (BTS1) together with a heterologous GGPP synthase from Sulfolobus acidocaldarius (SaGGPS). Auxotrophic markers in the episomal plasmids were then replaced by antibiotic markers, so that engineered yeast strains could use rich medium to obtain better cell growth while keeping plasmid stabilities. Over-expressing ERG20-BTS1 and SaGGPS genes increased miltiradiene production from 5.4 to 28.2?mg/L. Combinatorial over-expression of tHMGR-upc2.1 and ERG20-BTS1-SaGGPS genes had a synergetic effects on miltiradiene production, increasing titer to 61.8?mg/L. Finally, fed-batch fermentation was performed, and 488?mg/L miltiradiene was produced. The yeast strains engineered in this work provide a basis for creating an alternative way for production of tanshinones in place of extraction from plant sources. PMID:22566191

  14. Crystal structure of Saccharomyces cerevisiae 6-phosphogluconate dehydrogenase Gnd1

    Directory of Open Access Journals (Sweden)

    Zhou Cong-Zhao

    2007-06-01

    Full Text Available Abstract Background As the third enzyme of the pentose phosphate pathway, 6-phosphogluconate dehydrogenase (6PGDH is the main generator of cellular NADPH. Both thioredoxin reductase and glutathione reductase require NADPH as the electron donor to reduce oxidized thioredoxin or glutathione (GSSG. Since thioredoxin and GSH are important antioxidants, it is not surprising that 6PGDH plays a critical role in protecting cells from oxidative stress. Furthermore the activity of 6PGDH is associated with several human disorders including cancer and Alzheimer's disease. The 3D structural investigation would be very valuable in designing small molecules that target this enzyme for potential therapeutic applications. Results The crystal structure of 6-phosphogluconate dehydrogenase (6PGDH/Gnd1 from Saccharomyces cerevisiae has been determined at 2.37 Å resolution by molecular replacement. The overall structure of Gnd1 is a homodimer with three domains for each monomer, a Rossmann fold NADP+ binding domain, an all-? helical domain contributing the majority to hydrophobic interaction between the two subunits and a small C-terminal domain penetrating the other subunit. In addition, two citrate molecules occupied the 6PG binding pocket of each monomer. The intact Gnd1 had a Km of 50 ± 9 ?M for 6-phosphogluconate and of 35 ± 6 ?M for NADP+ at pH 7.5. But the truncated mutants without the C-terminal 35, 39 or 53 residues of Gnd1 completely lost their 6PGDH activity, despite remaining the homodimer in solution. Conclusion The overall tertiary structure of Gnd1 is similar to those of 6PGDH from other species. The substrate and coenzyme binding sites are well conserved, either from the primary sequence alignment, or from the 3D structural superposition. Enzymatic activity assays suggest a sequential mechanism of catalysis, which is in agreement with previous studies. The C-terminal domain of Gnd1 functions as a hook to further tighten the dimer, but it is not necessary for the dimerization. This domain also works as a lid on the substrate binding pocket to control the binding of substrate and the release of product, so it is indispensable for the 6PGDH activity. Moreover, the co-crystallized citrate molecules, which mimic the binding mode of the substrate 6-phosphogluconate, provided us a novel strategy to design the 6PDGH inhibitors.

  15. Heterologous expression and characterization of bacterial 2-C-methyl-d-erythritol-4-phosphate pathway in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Carlsen, Simon; Ajikumar, Parayil Kumaran

    2013-01-01

    Transfer of a biosynthetic pathway between evolutionary distant organisms can create a metabolic shunt capable of bypassing the native regulation of the host organism, hereby improving the production of secondary metabolite precursor molecules for important natural products. Here, we report the engineering of Escherichia coli genes encoding the 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway into the genome of Saccharomyces cerevisiae and the characterization of intermediate metabolites synthesized by the MEP pathway in yeast. Our UPLC-MS analysis of the MEP pathway metabolites from engineered yeast showed that the pathway is active until the synthesis of 2-C-methyl-d-erythritol-2,4-cyclodiphosphate, but appears to lack functionality of the last two steps of the MEP pathway, catalyzed by the [4Fe–4S] iron sulfur cluster proteins encoded by ispG and ispH. In order to functionalize the last two steps of the MEP pathway, we co-expressed the genes for the E. coli iron sulfur cluster (ISC) assembly machinery. Bydeleting ERG13, thereby incapacitating the mevalonate pathway, in conjunction with labeling experiments with U–13C6 glucose and growth experiments, we found that the ISC assembly machinery was unable to functionalize ispG and ispH. However, we have found that leuC and leuD, encoding the heterodimeric iron–sulfur cluster protein, isopropylmalate isomerase, can complement the S. cerevisiae leu1 auxotrophy. To our knowledge, this is the first time a bacterial iron–sulfur cluster protein has been functionally expressed in the cytosol of S. cerevisiae under aerobic conditions and shows that S. cerevisiae has the capability to functionally express at least some bacterial iron–sulfur cluster proteins in its cytosol.

  16. Increased isobutanol production in Saccharomyces cerevisiae by overexpression of genes in valine metabolism

    Directory of Open Access Journals (Sweden)

    Karhumaa Kaisa

    2011-07-01

    Full Text Available Abstract Background Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. Furthermore, the branched-chain structure of isobutanol gives a higher octane number than the isomeric n-butanol. Saccharomyces cerevisiae was chosen as the production host because of its relative tolerance to alcohols, robustness in industrial fermentations, and the possibility for future combination of isobutanol production with fermentation of lignocellulosic materials. Results The yield of isobutanol was improved from 0.16 to 0.97 mg per g glucose by simultaneous overexpression of biosynthetic genes ILV2, ILV3, and ILV5 in valine metabolism in anaerobic fermentation of glucose in mineral medium in S. cerevisiae. Isobutanol yield was further improved by twofold by the additional overexpression of BAT2, encoding the cytoplasmic branched-chain amino-acid aminotransferase. Overexpression of ILV6, encoding the regulatory subunit of Ilv2, in the ILV2 ILV3 ILV5 overexpression strain decreased isobutanol production yield by threefold. In aerobic cultivations in shake flasks in mineral medium, the isobutanol yield of the ILV2 ILV3 ILV5 overexpression strain and the reference strain were 3.86 and 0.28 mg per g glucose, respectively. They increased to 4.12 and 2.4 mg per g glucose in yeast extract/peptone/dextrose (YPD complex medium under aerobic conditions, respectively. Conclusions Overexpression of genes ILV2, ILV3, ILV5, and BAT2 in valine metabolism led to an increase in isobutanol production in S. cerevisiae. Additional overexpression of ILV6 in the ILV2 ILV3 ILV5 overexpression strain had a negative effect, presumably by increasing the sensitivity of Ilv2 to valine inhibition, thus weakening the positive impact of overexpression of ILV2, ILV3, and ILV5 on isobutanol production. Aerobic cultivations of the ILV2 ILV3 ILV5 overexpression strain and the reference strain showed that supplying amino acids in cultivation media gave a substantial improvement in isobutanol production for the reference strain, but not for the ILV2 ILV3 ILV5 overexpression strain. This result implies that other constraints besides the enzyme activities for the supply of 2-ketoisovalerate may become bottlenecks for isobutanol production after ILV2, ILV3, and ILV5 have been overexpressed, which most probably includes the valine inhibition to Ilv2.

  17. Increased isobutanol production in Saccharomyces cerevisiae by overexpression of genes in valine metabolism

    DEFF Research Database (Denmark)

    Chen, Xiao; Nielsen, Kristian Fog

    2011-01-01

    BACKGROUND: Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. Furthermore, the branched-chain structure of isobutanol gives a higher octane number than the isomeric n-butanol. Saccharomyces cerevisiae was chosen as the production host because of its relative tolerance to alcohols, robustness in industrial fermentations, and the possibility for future combination of isobutanol production with fermentation of lignocellulosic materials. RESULTS: The yield of isobutanol was improved from 0.16 to 0.97 mg per g glucose by simultaneous overexpression of biosynthetic genes ILV2, ILV3, and ILV5 in valine metabolism in anaerobic fermentation of glucose in mineral medium in S. cerevisiae. Isobutanol yield was further improved by twofold by the additional overexpression of BAT2, encoding the cytoplasmic branched-chain amino-acid aminotransferase. Overexpression of ILV6, encoding the regulatory subunit of Ilv2, in the ILV2 ILV3 ILV5 overexpression strain decreased isobutanol production yield by threefold. In aerobic cultivations in shake flasks in mineral medium, the isobutanol yield of the ILV2 ILV3 ILV5 overexpression strain and the reference strain were 3.86 and 0.28 mg per g glucose, respectively. They increased to 4.12 and 2.4 mg per g glucose in yeast extract/peptone/dextrose (YPD) complex medium under aerobic conditions, respectively. CONCLUSIONS: Overexpression of genes ILV2, ILV3, ILV5, and BAT2 in valine metabolism led to an increase in isobutanol production in S. cerevisiae. Additional overexpression of ILV6 in the ILV2 ILV3 ILV5 overexpression strain had a negative effect, presumably by increasing the sensitivity of Ilv2 to valine inhibition, thus weakening the positive impact of overexpression of ILV2, ILV3, and ILV5 on isobutanol production. Aerobic cultivations of the ILV2 ILV3 ILV5 overexpression strain and the reference strain showed that supplying amino acids in cultivation media gave a substantial improvement in isobutanol production for the referencestrain, but not for the ILV2 ILV3 ILV5 overexpression strain. This result implies that other constraints besides the enzyme activities for the supply of 2-ketoisovalerate may become bottlenecks for isobutanol production after ILV2, ILV3, and ILV5 have been overexpressed, which most probably includes the valine inhibition to Ilv2.

  18. Expresión heteróloga de un péptido multiepitópico de células B de M. tuberculosis en Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    María de los Angeles, García; María Elena, Sarmiento; Roberto, Coria; Laura, Kawasaky; Laura, Ongay; Juan Francisco, de la Rosa; Armando, Acosta.

    2007-08-01

    Full Text Available Saccharomyces cerevisiae ha sido ampliamente utilizada como sistema de expresión de proteínas heterólogas. El presente trabajo se encaminó hacia la expresión en Saccharomyces cerevisiae de un péptido de epitopes múltiples de M. tuberculosis. Con dicho propósito el péptido quimérico denominado B2 fue [...] clonado en dos vectores de expresión de esta levadura con promotores regulables por galactosa y sulfato cúprico, respectivamente. Luego de los experimentos de inducción, la expresión del péptido B2 fue analizada mediante SDS/PAGE y Western blot. El análisis por Western blot confirmó la expresión del péptido B2, al hacerse la inducción con 100 mM de CuSO4 durante toda la noche. No ocurrió así en los experimentos donde se utilizó la galactosa como inductor con todas las condiciones ensayadas. Estos resultados muestran que la levadura Saccharomyces cerevisiae pudiera ser un buen hospedero alternativo para la expresión de péptidos multiepitópicos de M. tuberculosis. Abstract in english Saccharomyces cerevisiae has been widely used as expression system of heterologous proteins. The aim of the present work was the expression in Saccharomyces cerevisiae of a class B multiepitopic peptide from M. tuberculosis. For this purpose, the chimerical peptide named B2 was cloned in two yeast e [...] xpression vectors containing galactose and cupric sulphate regulated promoters, respectively. After induction experiments, B2 expression was analyzed by SDS/PAGE and Western Blot. By Western Blot analysis B2 expression was confirmed when induction took place overnight with 100 mM of CuSO4. No expression signal took place when galactose was used as inductor. These results show that Sacchromyces cervisiae could be a good alternative host for the expression of multiepitopic peptides from M. tuberculosis.

  19. Improvement of oxidized glutathione fermentation by thiol redox metabolism engineering in Saccharomyces cerevisiae.

    Science.gov (United States)

    Hara, Kiyotaka Y; Aoki, Naoko; Kobayashi, Jyumpei; Kiriyama, Kentaro; Nishida, Keiji; Araki, Michihiro; Kondo, Akihiko

    2015-11-01

    Glutathione is a valuable tripeptide widely used in the pharmaceutical, food, and cosmetic industries. In industrial fermentation, glutathione is currently produced primarily using the yeast Saccharomyces cerevisiae. Intracellular glutathione exists in two forms; the majority is present as reduced glutathione (GSH) and a small amount is present as oxidized glutathione (GSSG). However, GSSG is more stable than GSH and is a more attractive form for the storage of glutathione extracted from yeast cells after fermentation. In this study, intracellular GSSG content was improved by engineering thiol oxidization metabolism in yeast. An engineered strain producing high amounts of glutathione from over-expression of glutathione synthases and lacking glutathione reductase was used as a platform strain. Additional over-expression of thiol oxidase (1.8.3.2) genes ERV1 or ERO1 increased the GSSG content by 2.9-fold and 2.0-fold, respectively, compared with the platform strain, without decreasing cell growth. However, over-expression of thiol oxidase gene ERV2 showed almost no effect on the GSSG content. Interestingly, ERO1 over-expression did not decrease the GSH content, raising the total glutathione content of the cell, but ERV1 over-expression decreased the GSH content, balancing the increase in the GSSG content. Furthermore, the increase in the GSSG content due to ERO1 over-expression was enhanced by additional over-expression of the gene encoding Pdi1, whose reduced form activates Ero1 in the endoplasmic reticulum. These results indicate that engineering the thiol redox metabolism of S. cerevisiae improves GSSG and is critical to increasing the total productivity and stability of glutathione. PMID:26239069

  20. Radiosensitivity of Saccharomyces cerevisiae W303-1A and BY4741 Strains

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2011-05-15

    Saccharomyces cerevisiae, a simple eukaryotic cell, has been widely used as a model for all eukaryotes including humans for the study of fundamental cellular processes such as DNA replication, DNA recombination, cell cycle, cell division and metabolism. Numerous laboratory strains are used in yeast research. Most of the mutants have been derived from the two widely used laboratory strains W303-1A and BY4741. While BY4741 is a derivative of S288C, used in the systematic sequencing of the S. cerevisiae genome, strains with a W303 background serve in many physiological and biochemical studies. It was found in a recent study that W303-1A contains a mutant allele of YBP1, ybp1-1, encoding four amino acid substitutions, that results in increased peroxide sensitivity. Mutation of ybp1-1 is not a complete loss of function allele as it is more resistant to peroxides than the knock-out mutant. Ybp1 is required for oxidation of specific cysteine residues of the transcription factor Yap1p resulting in the nuclear localization of Yap1p in response to stress. Ionizing radiation (IR) can produce highly reactive hydroxyl radicals through the decomposition of cellular water, such as superoxide anion radical, hydrogen peroxide, hydroxyl radical. These reactive oxygen species (ROS) can cause wide-ranging cellular damage, including DNA double-strand breaks (DSBs), lipid peroxidation, and protein modification. Also, ROS produced by IR cause oxidative stress. Detoxification enzymes are activated for ROS scavenging against oxidative stress. Also, antioxidants are used for detoxification of ROS and reduction of oxidative damage. NAC, one of the antioxidants, is a precursor for glutathione (GSH). The aim of the present study was to compare the differences in radiosensitivity associated cell viability between the two strains. Also, effect of NAC against IR on cell protection was investigated

  1. Transcription of hexose transporters of Saccharomyces cerevisiae is affected by change in oxygen provision

    Directory of Open Access Journals (Sweden)

    Ruohonen Laura

    2008-03-01

    Full Text Available Abstract Background The gene family of hexose transporters in Saccharomyces cerevisiae consists of 20 members; 18 genes encoding transporters (HXT1-HXT17, GAL2 and two genes encoding sensors (SNF3, RGT2. The effect of oxygen provision on the expression of these genes was studied in glucose-limited chemostat cultivations (D = 0.10 h-1, pH 5, 30°C. Transcript levels were measured from cells grown in five steady state oxygen levels (0, 0.5, 1, 2.8 and 20.9% O2, and from cells under conditions in which oxygen was introduced to anaerobic cultures or removed from cultures receiving oxygen. Results The expression pattern of the HXT gene family was distinct in cells grown under aerobic, hypoxic and anaerobic conditions. The transcription of HXT2, HXT4 and HXT5 was low when the oxygen concentration in the cultures was low, both under steady state and non-steady state conditions, whereas the expression of HXT6, HXT13 and HXT15/16 was higher in hypoxic than in fully aerobic or anaerobic conditions. None of the HXT genes showed higher transcript levels in strictly anaerobic conditions. Expression of HXT9, HXT14 and GAL2 was not detected under the culture conditions studied. Conclusion When oxygen becomes limiting in a glucose-limited chemostat cultivation, the glucose uptake rate per cell increases. However, the expression of none of the hexose transporter encoding genes was increased in anaerobic conditions. It thus seems that the decrease in the moderately low affinity uptake and consequently the relative increase of high affinity uptake may itself allow the higher specific glucose consumption rate to occur in anaerobic compared to aerobic conditions.

  2. A metabolic and genomic study of engineered Saccharomyces cerevisiae strains for high glycerol production.

    Science.gov (United States)

    Cordier, Hélène; Mendes, Filipa; Vasconcelos, Isabel; François, Jean M

    2007-07-01

    Towards a global objective to produce chemical derivatives by microbial processes, this work dealt with a metabolic engineering of the yeast Saccharomyces cerevisiae for glycerol production. To accomplish this goal, overexpression of GPD1 was introduced in a tpi1delta mutant defective in triose phosphate isomerase. This strategy alleviated the inositol-less phenotype of this mutant, by reducing the levels of dihydroxyacetone phosphate and glycerol-3-P, two potent inhibitors of myo-inositol synthase that catalyzes the formation of inositol-6-phosphate from glucose-6-phosphate. Further deletion of ADH1 and overexpression of ALD3, encoding, respectively, the major NAD+-dependent alcohol dehydrogenase and a cytosolic NAD+-dependent aldehyde dehydrogenase yielded a yeast strain able to produce 0.46 g glycerol (g glucose)(-1) at a maximal rate of 3.1 mmol (g dry mass)(-1) h(-1) in aerated batch cultures. At the metabolic level, this genetic strategy shifted the flux control coefficient of the pathway to the level of the glycerol efflux, with a consequent intracellular accumulation of glycerol that could be partially reduced by the overproduction of glycerol exporter encoded by FPS1. At the transcriptomic level, this metabolic reprogramming brought about the upregulation of genes encoding NAD+/NADP+ binding proteins, a partial derepression of genes coding for TCA cycle and respiratory enzymes, and a downregulation of genes implicated in protein biosynthesis and ribosome biogenesis. Altogether, these metabolic and molecular alterations stand for major hurdles that may represent potential targets for further optimizing glycerol production in yeast. PMID:17500021

  3. De novo production of resveratrol from glucose or ethanol by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Li, Mingji; Kildegaard, Kanchana R; Chen, Yun; Rodriguez, Angelica; Borodina, Irina; Nielsen, Jens

    2015-11-01

    Resveratrol is a natural antioxidant compound, used as food supplement and cosmetic ingredient. Microbial production of resveratrol has until now been achieved by supplementation of expensive substrates, p-coumaric acid or aromatic amino acids. Here we engineered the yeast Saccharomyces cerevisiae to produce resveratrol directly from glucose or ethanol via tyrosine intermediate. First we introduced the biosynthetic pathway, consisting of tyrosine ammonia-lyase from Herpetosiphon aurantiacus, 4-coumaryl-CoA ligase from Arabidopsis thaliana and resveratrol synthase from Vitis vinifera, and obtained 2.73±0.05mgL(-1) resveratrol from glucose. Then we over-expressed feedback-insensitive alleles of ARO4 encoding 3-deoxy-D-arabino-heptulosonate-7-phosphate and ARO7 encoding chorismate mutase, resulting in production of 4.85±0.31mgL(-1) resveratrol from glucose as the sole carbon source. Next we improved the supply of the precursor malonyl-CoA by over-expressing a post-translational de-regulated version of the acetyl-CoA carboxylase encoding gene ACC1; this strategy further increased resveratrol production to 6.39±0.03mgL(-1). Subsequently, we improved the strain by performing multiple-integration of pathway genes resulting in resveratrol production of 235.57±7.00mgL(-1). Finally, fed-batch fermentation of the final strain with glucose or ethanol as carbon source resulted in a resveratrol titer of 415.65 and 531.41mgL(-1), respectively. PMID:26344106

  4. Homologous Recombination Repair Within the rDNA Array in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    M. Motovali-Bashi

    2007-01-01

    Full Text Available Homologous recombination repair starts with Double-strand Breaks (DSBs followed by crossing-over and recombination. The expected frequency of meiotic chromosomal exchange in the region of chromosome XII encoding ribosomal DNA in Saccharomyces cerevisiae is 3.5 to 5 events per cell per meiosis. However interchromosomal meiotic recombination in the rDNA gene is very rare, suggesting repression of DSB and crossing-over. On the other hand, mitotic events such as intrachromosomal recombination producing 3 ?m rDNA circles (which accumulate with cellular age and unequal sister chromatid exchanges appear to be quite common. This study looked at the rDNA breakage in the strain ORD 1181, a rad50S mutant with SK1 background, which does a relatively fast and near synchronous meiosis. The fine analysis of the rDNA array was performed using restriction endonuclease enzymes that do not cleave within the rDNA array. The results suggest that there are at least two hot regions for chromosome breakage within the rDNA array. According to our previous studies we suggest that the DSB hot regions are in one homologue. However, there is possibility that other homologue is involving in DSB too.

  5. Quantitative modeling of the Saccharomyces cerevisiae FLR1 regulatory network using an S-system formalism.

    Science.gov (United States)

    Calçada, Dulce; Vinga, Susana; Freitas, Ana T; Oliveira, Arlindo L

    2011-10-01

    In this study we address the problem of finding a quantitative mathematical model for the genetic network regulating the stress response of the yeast Saccharomyces cerevisiae to the agricultural fungicide mancozeb. An S-system formalism was used to model the interactions of a five-gene network encoding four transcription factors (Yap1, Yrr1, Rpn4 and Pdr3) regulating the transcriptional activation of the FLR1 gene. Parameter estimation was accomplished by decoupling the resulting system of nonlinear ordinary differential equations into a larger nonlinear algebraic system, and using the Levenberg-Marquardt algorithm to fit the models predictions to experimental data. The introduction of constraints in the model, related to the putative topology of the network, was explored. The results show that forcing the network connectivity to adhere to this topology did not lead to better results than the ones obtained using an unrestricted network topology. Overall, the modeling approach obtained partial success when trained on the nonmutant datasets, although further work is required if one wishes to obtain more accurate prediction of the time courses. PMID:21976379

  6. Transcriptional profiling in Saccharomyces cerevisiae relevant for predicting alachlor mechanisms of toxicity.

    Science.gov (United States)

    Gil, Fátima N; Gonçalves, Alina C; Jacinto, Maria João; Becker, Jörg D; Viegas, Cristina A

    2011-11-01

    Alachlor has been a commonly applied herbicide and is a substance of ecotoxicological concern. The present study aims to identify molecular biomarkers in the eukaryotic model Saccharomyces cerevisiae that can be used to predict potential cytotoxic effects of alachlor, while providing new mechanistic clues with possible relevance for experimentally less accessible eukaryotes. It focuses on genome-wide expression profiling in a yeast population in response to two exposure scenarios exerting effects from slight to moderate magnitude at phenotypic level. In particular, 100 and 264 genes, respectively, were found as differentially expressed on a 2-h exposure of yeast cells to the lowest observed effect concentration (110 mg/L) and the 20% inhibitory concentration (200 mg/L) of alachlor, in comparison with cells not exposed to the herbicide. The datasets of alachlor-responsive genes showed functional enrichment in diverse metabolic, transmembrane transport, cell defense, and detoxification categories. In general, the modifications in transcript levels of selected candidate biomarkers, assessed by quantitative reverse transcriptase polymerase chain reaction, confirmed the microarray data and varied consistently with the growth inhibitory effects of alachlor. Approximately 16% of the proteins encoded by alachlor-differentially expressed genes were found to share significant homology with proteins from ecologically relevant eukaryotic species. The biological relevance of these results is discussed in relation to new insights into the potential adverse effects of alachlor in health of organisms from ecosystems, particularly in worst-case situations such as accidental spills or careless storage, usage, and disposal. PMID:21842488

  7. Multiple gene mediated aldehyde reduction is a mechanism of in situ detoxification of furfural and 5-hydroxymethylfurfural by Saccharomyces cerevisiae

    Science.gov (United States)

    Furfural and HMF (5-hydroxymethylfurfural) are representative inhibitors to ethanologenic yeast generated from biomass pretreatment using dilute acid hydrolysis. Few yeast strains tolerant to inhibitors are available. We have developed tolerant strains of Saccharomyces cerevisiae with enhanced bio...

  8. Characterization of a glucose-repressed pyruvate kinase (Pyk2p) in Saccharomyces cerevisiae that is catalytically insensitive to fructose-1,6-bisphosphate.

    OpenAIRE

    Boles, E.; Schulte, F.; Miosga, T.; Freidel, K; Schlüter, E; Zimmermann, F K; Hollenberg, C P; Heinisch, J J

    1997-01-01

    We have characterized the gene YOR347c of Saccharomyces cerevisiae and shown that it encodes a second functional pyruvate kinase isoenzyme, Pyk2p. Overexpression of the YOR347c/PYK2 gene on a multicopy vector restored growth on glucose of a yeast pyruvate kinase 1 (pyk1) mutant strain and could completely substitute for the PYK1-encoded enzymatic activity. PYK2 gene expression is subject to glucose repression. A pyk2 deletion mutant had no obvious growth phenotypes under various conditions, b...

  9. Microbial cells as biosorbents for heavy metals: accumulation of Uranium by Saccharomyces cerevisiae and Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Uranium accumulated extracellularly on the surfaces of Saccharomyces cerevisiae cells. The rate and extent of accumulation were subject to environmental parameters, such as pH, temperature, and interference by certain anions and cations. Uranium accumulation by Pseudomonas aeruginosa occurred intracellularly and was extremely rapid (<10 s), and no response to environmental parameters could be detected. Metabolism was not required for metal uptake by either organism. Cell-bound uranium reached a concentration of 10 to 15% of the dry cell weight, but only 32% of the S. cerevisiae cells and 44% of the P. aeruginosa cells within a given population possessed visible uranium deposits when examined by electron microscopy. Rates of uranium uptake by S. cerevisiae were increased by chemical pretreatment of the cells. Uranium could be removed chemically from S. cerevisiae cells, and the cells could then be reused as a biosorbent

  10. Functional co-operation between the nuclei of Saccharomyces cerevisiae and mitochondria from other yeast species

    DEFF Research Database (Denmark)

    Spirek, M.; Horvath, A.

    2000-01-01

    We elaborated a simple method that allows the transfer of mitochondria from collection yeasts to Saccharomyces cerevisiae. Protoplasts prepared from different yeasts were fused to the protoplasts of the ade2-1, ura3-52, kar1-1, rho (0) strain of S. cerevisiae and were selected for respiring cybrids on plates containing 5-fluoroorotic acid and a non-fermentable carbon source. The identity of putative cybrids was assessed by restriction analysis of mitochondrial DNA, pulse field electrophoresis and tetrad analysis. In the comprehensive screening, only mitochondrial genomes from synonymous species (S. italicus, S, oviformis, S. capensis and S. chevalieri) exhibited complete compatibility with S. cerevisiae nuclei. The closely related S. douglasii mitochondrial genome could also partially restore respiration-deficiency in rho (0) S. cerevisiae, whereas mitochondrial genomes from phylogenetically less related species could not.

  11. Systems Biology of Saccharomyces cerevisiae Physiology and its DNA Damage Response

    DEFF Research Database (Denmark)

    Fazio, Alessandro

    2010-01-01

    The yeast Saccharomyces cerevisiae is a model organism in biology, being widely used in fundamental research, the first eukaryotic organism to be fully sequenced and the platform for the development of many genomics techniques. Therefore, it is not surprising that S. cerevisiae has also been widely used in the field of systems biology during the last decade. This thesis investigates S. cerevisiae growth physiology and DNA damage response by using a systems biology approach. Elucidation of the relationship between growth rate and gene expression is important to understand the mechanisms regulating cell growth. In order to study this relationship, we have grown S. cerevisiae cells in chemostat at defined growth rates and measured the transcriptional response. We have applied a complex experimental design, involving three factors: specific growth rate, oxygen availability and nutrient limitation. We have identified 268 growth rate dependent genes. These genes were used to identify key areas of the metabolism around which expression changes were significantly associated and we found nucleotide synthesis and ATP producing and consuming reactions. Moreover, by scoring the significance of overlap between growth rate dependent genes and known transcription factor (TF) target sets, we identified 13 TFs, involved in stress response, cell cycle and ribosome biogenesis, that appeared to coordinate the response at increasing growth rates. Therefore, in this study we have identified a more conservative set of growth dependent genes by using a multi-factorial experimental design. Moreover, new insights into the metabolic response and transcriptional regulation of these genes have been provided by using systems biology tools (Chapter 3). One of the prerequisite of systems biology should be the standardization and reproducibility of experimental and analytical techniques, in order to allow the comparison of data generated in different laboratories. With the aim of addressing this aspect, we have collaborated in a large study involving ten laboratories, constituting the Yeast Systems Biology Network (YSBN). S. cerevisiae cultivations were performed in a single laboratory and samples were sent to the other partners. The experimental design involved two factors: strain (CEN.PK113-7D and YSBN2) and growth condition (batch and chemostat). Transcriptome was measured with four different platforms (Affymetrix, Agilent, qPCR and TRAC), metabolome was analyzed in seven laboratories, using different protocols, and enzyme activities were determined in two different laboratories. The comparison of the analyses showed that reproducibility of the results was affected by the laboratory and the protocol used. Transcription and enzyme activity analyses gave consistent results, while metabolite level measurements showed some variability. Therefore, even though the source of biomass was unique, the reproducibility of data appeared to be a challenging task. Nevertheless, we were able to perform an integrative analysis and discover that the lower biomass yield of CEN.PK113-7D was due to higher protein turnover than YSBN2; this finding would not be achievable using a single omics dataset. Moreover, the generated datasets are a valuable resource for the yeast systems biology community (Chapter 4). Upon DNA damage, S. cerevisiae cells respond activating the so-called cell cycle checkpoints that promote damage repair and viability. The activation of these checkpoints depends on kinase cascades and regulation of transcription is one of the responses elicited by checkpoint activation. Therefore, we have decided to investigate the transcriptional and phenotypic responses to the alkylating agent methyl methanesulfonate (MMS) of mutant strains carrying deletions of genes encoding protein kinases (Mec1, Tel1, Rad53, Dun1, Chk1, Alk1) and protein phosphatases (Ptc3, Pph3, Oca1) involved in DNA damage response (DDR). We have discovered a prominent role for Rad53, Mec1 and Tel1 in transcriptional response. Moreover, we have shown for the first time the important role of O

  12. Performance evaluation of Pichia kluyveri, Kluyveromyces marxianus and Saccharomyces cerevisiae in industrial tequila fermentation.

    Science.gov (United States)

    Amaya-Delgado, L; Herrera-López, E J; Arrizon, Javier; Arellano-Plaza, M; Gschaedler, A

    2013-05-01

    Traditionally, industrial tequila production has used spontaneous fermentation or Saccharomyces cerevisiae yeast strains. Despite the potential of non-Saccharomyces strains for alcoholic fermentation, few studies have been performed at industrial level with these yeasts. Therefore, in this work, Agave tequilana juice was fermented at an industrial level using two non-Saccharomyces yeasts (Pichia kluyveri and Kluyveromyces marxianus) with fermentation efficiency higher than 85 %. Pichia kluyveri (GRO3) was more efficient for alcohol and ethyl lactate production than S. cerevisiae (AR5), while Kluyveromyces marxianus (GRO6) produced more isobutanol and ethyl-acetate than S. cerevisiae (AR5). The level of volatile compounds at the end of fermentation was compared with the tequila standard regulation. All volatile compounds were within the allowed range except for methanol, which was higher for S. cerevisiae (AR5) and K. marxianus (GRO6). The variations in methanol may have been caused by the Agave tequilana used for the tests, since this compound is not synthesized by these yeasts. PMID:23329062

  13. Transcriptome-Based Characterization of Interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in Lactose-Grown Chemostat Cocultures

    OpenAIRE

    Mendes, Filipa; Sieuwerts, Sander; de Hulster, Erik; Almering, Marinka J. H.; Luttik, Marijke A. H.; Pronk, Jack T; Smid, Eddy J; Bron, Peter A.; Daran-Lapujade, Pascale

    2013-01-01

    Mixed populations of Saccharomyces cerevisiae yeasts and lactic acid bacteria occur in many dairy, food, and beverage fermentations, but knowledge about their interactions is incomplete. In the present study, interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus, two microorganisms that co-occur in kefir fermentations, were studied during anaerobic growth on lactose. By combining physiological and transcriptome analysis of the two strains in the cocultu...

  14. Correlation between ethanol stress and cellular fatty acid composition of alcohol producing non-Saccharomyces in comparison with Saccharomyces cerevisiae by multivariate techniques.

    Science.gov (United States)

    Archana, K M; Ravi, R; Anu-Appaiah, K A

    2015-10-01

    Wine production is a complex process both from biochemical and microbiological point of view in which yeast plays a central role. The use of the wine yeast Saccharomyces cerevisiae and non- Saccharomyces yeasts as mixed starter cultures for wine fermentations is of increasing interest to enhance the quality of wine.The most common stress, yeast cells encounter during wine fermentation is the increase in ethanol concentration.To enhance ethanol tolerance, alteration in the cellular lipid composition is one of its defence mechanism. Ethanol tolerance and cellular fatty acid composition of alcohol producing non Saccharomyces forms were compared with enological strains of Sacccharomyces cerevisiae. Saccharomyces cerevisiae used for the study, tolerated 15 % of ethanol and the non Saccharomyces strains such as, Issatchenkia occidentalis and Issatchenkia orientalis tolerated 10 % of ethanol. On exposure of Saccharomyces cerevisiae to ethanol stress, the proportion of monounsaturated fatty acids increased with concomitant decrease in saturated fatty acids. Decrease in monounsaturated fatty acids, exhibited by non-Saccharomyces yeasts when exposed to ethanol stress, could be one of the reasons for their inability to withstand more than 10 % of alcohol. Multivariate techniques of data analysis - principal component analysis and linear discriminant analysis were employed in order to establish differentiation criteria as function of yeast strains, alcohol stress and their fatty acid profile. Based on the data, Chemometrics, such as principal component analysis and discriminant function analysis, can be successfully applied to fatty acid data to categorize the yeast. PMID:26396428

  15. "A comparison between sugar consumption and ethanol production in wort by immobilized Saccharomyces Cerevisiae, Saccharomyces Ludwigii and Saccharomyces Rouxii on Brewer's Spent Grain"

    Directory of Open Access Journals (Sweden)

    Aniseh Mohammadi

    2011-06-01

    Full Text Available The immobilization of Saccharomyces cerevisiae DSM 70424, Saccharomyces ludwigii DSM 3447 and Saccharomyces rouxii DSM 2531 on brewer's spent grain and then ethanol production and sugar consumption of these immobilized yeasts were investigated. The aim of this study was to investigate the abilities of these three immobilized yeasts for producing alcohol for brewing at two temperatures (7 and 12 °C using two different sugar levels (one at original level supplied in the brewery and one with 2.5% (w/v, added glucose to the wort. Increasing both parameters resulted in higher alcohol production by all the yeasts studied. At 7 °C and with original wort density the ethanol content at the end of fermentation was 2.7% (v/v for S. cerevisiae, 1.7% for S. ludwigii and 2.0% for S. rouxii. After the addition of 2.5% (w/v glucose at the same temperature (7 °C, the alcohol production was increased to 4.1, 2.8 and 4.1%, respectively. Similar improvements were observed when the fermentation was carried out at 12 °C with/without the addition of glucose to the wort. However, temperature indicated greater influence on S. ludwigii than did on S. rouxii and S. cerevisiae. The immobilization as carried out in this study impacted both S. ludwigii and S. rouxii in a way that they could consume maltose under certain conditions.

  16. “A comparison between sugar consumption and ethanol production in wort by immobilized Saccharomyces Cerevisiae, Saccharomyces Ludwigii and Saccharomyces Rouxii on Brewer’S Spent Grain”

    Science.gov (United States)

    Mohammadi, Aniseh; Razavi, Seyyed Hadi; Mousavi, Seyyed Mohammad; Rezaei, Karamatollah

    2011-01-01

    The immobilization of Saccharomyces cerevisiae DSM 70424, Saccharomyces ludwigii DSM 3447 and Saccharomyces rouxii DSM 2531 on brewer’s spent grain and then ethanol production and sugar consumption of these immobilized yeasts were investigated. The aim of this study was to investigate the abilities of these three immobilized yeasts for producing alcohol for brewing at two temperatures (7 and 12 °C) using two different sugar levels (one at original level supplied in the brewery and one with 2.5% (w/v), added glucose to the wort). Increasing both parameters resulted in higher alcohol production by all the yeasts studied. At 7 °C and with original wort density the ethanol content at the end of fermentation was 2.7% (v/v) for S. cerevisiae, 1.7% for S. ludwigii and 2.0% for S. rouxii. After the addition of 2.5% (w/v) glucose at the same temperature (7 °C), the alcohol production was increased to 4.1, 2.8 and 4.1%, respectively. Similar improvements were observed when the fermentation was carried out at 12 °C with/without the addition of glucose to the wort. However, temperature indicated greater influence on S. ludwigii than did on S. rouxii and S. cerevisiae. The immobilization as carried out in this study impacted both S. ludwigii and S. rouxii in a way that they could consume maltose under certain conditions. PMID:24031672

  17. "A comparison between sugar consumption and ethanol production in wort by immobilized Saccharomyces Cerevisiae, Saccharomyces Ludwigii and Saccharomyces Rouxii on Brewer'S Spent Grain".

    Science.gov (United States)

    Mohammadi, Aniseh; Razavi, Seyyed Hadi; Mousavi, Seyyed Mohammad; Rezaei, Karamatollah

    2011-04-01

    The immobilization of Saccharomyces cerevisiae DSM 70424, Saccharomyces ludwigii DSM 3447 and Saccharomyces rouxii DSM 2531 on brewer's spent grain and then ethanol production and sugar consumption of these immobilized yeasts were investigated. The aim of this study was to investigate the abilities of these three immobilized yeasts for producing alcohol for brewing at two temperatures (7 and 12 °C) using two different sugar levels (one at original level supplied in the brewery and one with 2.5% (w/v), added glucose to the wort). Increasing both parameters resulted in higher alcohol production by all the yeasts studied. At 7 °C and with original wort density the ethanol content at the end of fermentation was 2.7% (v/v) for S. cerevisiae, 1.7% for S. ludwigii and 2.0% for S. rouxii. After the addition of 2.5% (w/v) glucose at the same temperature (7 °C), the alcohol production was increased to 4.1, 2.8 and 4.1%, respectively. Similar improvements were observed when the fermentation was carried out at 12 °C with/without the addition of glucose to the wort. However, temperature indicated greater influence on S. ludwigii than did on S. rouxii and S. cerevisiae. The immobilization as carried out in this study impacted both S. ludwigii and S. rouxii in a way that they could consume maltose under certain conditions. PMID:24031672

  18. "A comparison between sugar consumption and ethanol production in wort by immobilized Saccharomyces Cerevisiae, Saccharomyces Ludwigii and Saccharomyces Rouxii on Brewer's Spent Grain"

    Scientific Electronic Library Online (English)

    Aniseh, Mohammadi; Seyyed Hadi, Razavi; Seyyed Mohammad, Mousavi; Karamatollah, Rezaei.

    2011-06-01

    Full Text Available The immobilization of Saccharomyces cerevisiae DSM 70424, Saccharomyces ludwigii DSM 3447 and Saccharomyces rouxii DSM 2531 on brewer's spent grain and then ethanol production and sugar consumption of these immobilized yeasts were investigated. The aim of this study was to investigate the abilities [...] of these three immobilized yeasts for producing alcohol for brewing at two temperatures (7 and 12 °C) using two different sugar levels (one at original level supplied in the brewery and one with 2.5% (w/v), added glucose to the wort). Increasing both parameters resulted in higher alcohol production by all the yeasts studied. At 7 °C and with original wort density the ethanol content at the end of fermentation was 2.7% (v/v) for S. cerevisiae, 1.7% for S. ludwigii and 2.0% for S. rouxii. After the addition of 2.5% (w/v) glucose at the same temperature (7 °C), the alcohol production was increased to 4.1, 2.8 and 4.1%, respectively. Similar improvements were observed when the fermentation was carried out at 12 °C with/without the addition of glucose to the wort. However, temperature indicated greater influence on S. ludwigii than did on S. rouxii and S. cerevisiae. The immobilization as carried out in this study impacted both S. ludwigii and S. rouxii in a way that they could consume maltose under certain conditions.

  19. Transcription activator-like effector nucleases mediated metabolic engineering for enhanced fatty acids production in Saccharomyces cerevisiae

    KAUST Repository

    Aouida, Mustapha

    2015-04-01

    Targeted engineering of microbial genomes holds much promise for diverse biotechnological applications. Transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats/Cas9 systems are capable of efficiently editing microbial genomes, including that of Saccharomyces cerevisiae. Here, we demonstrate the use of TALENs to edit the genome of S.cerevisiae with the aim of inducing the overproduction of fatty acids. Heterodimeric TALENs were designed to simultaneously edit the FAA1 and FAA4 genes encoding acyl-CoA synthetases in S.cerevisiae. Functional yeast double knockouts generated using these TALENs over-produce large amounts of free fatty acids into the cell. This study demonstrates the use of TALENs for targeted engineering of yeast and demonstrates that this technology can be used to stimulate the enhanced production of free fatty acids, which are potential substrates for biofuel production. This proof-of-principle study extends the utility of TALENs as excellent genome editing tools and highlights their potential use for metabolic engineering of yeast and other organisms, such as microalgae and plants, for biofuel production. © 2015 The Society for Biotechnology, Japan.

  20. Impact of overexpressing NADH kinase on glucose and xylose metabolism in recombinant xylose-utilizing Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hou, Jin; Vemuri, G. N.

    2009-01-01

    During growth of Saccharomyces cerevisiae on glucose, the redox cofactors NADH and NADPH are predominantly involved in catabolism and biosynthesis, respectively. A deviation from the optimal level of these cofactors often results in major changes in the substrate uptake and biomass formation. However, the metabolism of xylose by recombinant S. cerevisiae carrying xylose reductase and xylitol dehydrogenase from the fungal pathway requires both NADH and NADPH and creates cofactor imbalance during growth on xylose. As one possible solution to overcoming this imbalance, the effect of overexpressing the native NADH kinase (encoded by the POS5 gene) in xylose-consuming recombinant S. cerevisiae directed either into the cytosol or to the mitochondria was evaluated. The physiology of the NADH kinase containing strains was also evaluated during growth on glucose. Overexpressing NADH kinase in the cytosol redirected carbon flow from CO2 to ethanol during aerobic growth on glucose and to ethanol and acetate during anaerobic growth on glucose. However, cytosolic NADH kinase has an opposite effect during anaerobic metabolism of xylose consumption by channeling carbon flow from ethanol to xylitol. In contrast, overexpressing NADH kinase in the mitochondria did not affect the physiology to a large extent. Overall, although NADH kinase did not increase the rate of xylose consumption, we believe that it can provide an important source of NADPH in yeast, which can be useful for metabolic engineering strategies where the redox fluxes are manipulated.

  1. Evaluation of Brachypodium distachyon L-Tyrosine Decarboxylase Using L-Tyrosine Over-Producing Saccharomyces cerevisiae.

    Science.gov (United States)

    Noda, Shuhei; Shirai, Tomokazu; Mochida, Keiichi; Matsuda, Fumio; Oyama, Sachiko; Okamoto, Mami; Kondo, Akihiko

    2015-01-01

    To demonstrate that herbaceous biomass is a versatile gene resource, we focused on the model plant Brachypodium distachyon, and screened the B. distachyon for homologs of tyrosine decarboxylase (TDC), which is involved in the modification of aromatic compounds. A total of 5 candidate genes were identified in cDNA libraries of B. distachyon and were introduced into Saccharomyces cerevisiae to evaluate TDC expression and tyramine production. It is suggested that two TDCs encoded in the transcripts Bradi2g51120.1 and Bradi2g51170.1 have L-tyrosine decarboxylation activity. Bradi2g51170.1 was introduced into the L-tyrosine over-producing strain of S. cerevisiae that was constructed by the introduction of mutant genes that promote deregulated feedback inhibition. The amount of tyramine produced by the resulting transformant was 6.6-fold higher (approximately 200 mg/L) than the control strain, indicating that B. distachyon TDC effectively converts L-tyrosine to tyramine. Our results suggest that B. distachyon possesses enzymes that are capable of modifying aromatic residues, and that S. cerevisiae is a suitable host for the production of L-tyrosine derivatives. PMID:25996877

  2. Tomato QM-like protein protects Saccharomyces cerevisiae cells against oxidative stress by regulating intracellular proline levels.

    Science.gov (United States)

    Chen, Changbin; Wanduragala, Srimevan; Becker, Donald F; Dickman, Martin B

    2006-06-01

    Exogenous proline can protect cells of Saccharomyces cerevisiae from oxidative stress. We altered intracellular proline levels by overexpressing the proline dehydrogenase gene (PUT1) of S. cerevisiae. Put1p performs the first enzymatic step of proline degradation in S. cerevisiae. Overexpression of Put1p results in low proline levels and hypersensitivity to oxidants, such as hydrogen peroxide and paraquat. A put1-disrupted yeast mutant deficient in Put1p activity has increased protection from oxidative stress and increased proline levels. Following a conditional life/death screen in yeast, we identified a tomato (Lycopersicon esculentum) gene encoding a QM-like protein (tQM) and found that stable expression of tQM in the Put1p-overexpressing strain conferred protection against oxidative damage from H2O2, paraquat, and heat. This protection was correlated with reactive oxygen species (ROS) reduction and increased proline accumulation. A yeast two-hybrid system assay was used to show that tQM physically interacts with Put1p in yeast, suggesting that tQM is directly involved in modulating proline levels. tQM also can rescue yeast from the lethality mediated by the mammalian proapoptotic protein Bax, through the inhibition of ROS generation. Our results suggest that tQM is a component of various stress response pathways and may function in proline-mediated stress tolerance in plants. PMID:16751508

  3. Comportamento celular e resposta antioxidante diferenciados de Saccharomyces cerevisiae e de Saccharomyces chevalieri ao metavanadato de amónio / Different cellular behaviour and antioxidant response of Saccharomyces cerevisiae and Saccharomyces chevalieri growing in presence of ammonium metavanadate

    Scientific Electronic Library Online (English)

    R., Ferreira; I., Alves-Pereira; S., Magriço; C., Ferraz-Franco.

    2007-01-01

    Full Text Available A fermentação do vinho é um processo microbiológico complexo que requere a presença de leveduras adaptadas a condições de stresse. No ambiente celular de organismos aeróbios ocorrem naturalmente espécies reactivas de oxigénio (ROS) como subprodutos da respiração mitocondrial. A elevada reactividade [...] destas espécies químicas pode gerar danos moleculares que, em alguns casos, levam à morte celular. Em condições fisiológicas normais ou como resposta ao stresse oxidativo, a célula pode desencadear respostas adaptativas que envolvem mecanismos antioxidantes como os enzimas glutationo redutase (GR; EC 1.6.4.2) e catalases T (CAT T; EC 1.11.1.6) e A (CAT A; EC 1.11.1.6). O vanádio, um metal pesado presente em alguns fitofármacos, pode também com portar-se como um gerador de ROS, alterando o estado redox intracelular e exercendo efeitos nocivos em leveduras expostas a quantidade excessiva deste elemento. O principal objectivo deste trabalho foi comparar o efeito do metavanadato de amónio (NH4VO3), um sal pentavalente de vanádio, na viabilidade celular e nas actividades enzimáticas GR, CAT T e CAT A das leveduras vínicas Saccharomyces cerevisiae UE-ME3 e Saccharomyces chevalieri UE-ME1. Os resultados obtidos mostram que S. chevalieri UE-ME1 revelou menor tolerância ao NH4VO3 do que S. cerevisiae UE-ME3, uma vez que culturas de S. chevalieri não sobreviveram para valores de concentração do sal de vanádio superiores a 7,5 mM enquanto que células de S. cerevisiae mantiveram-se viáveis em presença de metavanadato de amónio 75 mM. As actividades enzimáticas estudadas apresentaram em S. chevalieri valores muito inferiores aos que foram determinados em S. cerevisiae embora em ambas as espécies de levedura o NH4VO3 pareça comportarse como um indutor de stresse oxidativo ao provocar um decréscimo significativo da actividade GR (P Abstract in english The fermentation of wine is a complex microbiological process which requires yeast adaptation to stress conditions. In the cellular environment of aerobic organisms naturally reactive oxygen species (ROS) occurs as by-products of mitochondrial respiration. The higher reactivity of these chemical spe [...] cies could cause molecular damages that in several cases induce cellular death. In common physiological conditions or as response to oxidative stress, the cell can generate adapted responses which involve antioxidants mechanisms as glutathione reductase (GR; EC 1.6.4.2) and catalase T (CAT T; EC 1.11.1.6) and A (CAT A; EC 1.11.1.6) enzymes. Vanadium, a heavy metal present in several pesticides could generate ROS changing the intracellular redox state and cause deleterious effects in yeasts exposed to higher levels of this element. The main objective of this work was to compare the effects of ammonium metavanadate (NH4VO3), a pentavalent salt of vanadium on cellular viability and GR, CAT T and CAT A activities of wine yeast Saccharomyces cerevisiae UE-ME3 and Saccharomyces chevalieri UE-ME1. The results obtained show that S. chevalieri UE-ME1 has lower tolerance to NH4VO3 than S. cerevisiae UE-ME3, since S. chevalieri cultures do not survive to concentration values of ammonium metavanadate higher than 7,5 mM, whereas S. cerevisiae cells are still viable in the presence of 75 mM. S. chevalieri has an enzymatic activity lower than S. cerevisiae, although for both yeast species NH4VO3 could behave as oxidative stress inductor, causing a significant decrease of GR activity (P

  4. Similarities and differences in the biochemical and enzymological properties of the four isomaltases from Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Xu Deng

    2014-01-01

    Full Text Available The yeast Saccharomyces cerevisiae IMA multigene family encodes four isomaltases sharing high sequence identity from 65% to 99%. Here, we explore their functional diversity, with exhaustive in-vitro characterization of their enzymological and biochemical properties. The four isoenzymes exhibited a preference for the ?-(1,6 disaccharides isomaltose and palatinose, with Michaëlis–Menten kinetics and inhibition at high substrates concentration. They were also able to hydrolyze trisaccharides bearing an ?-(1,6 linkage, but also ?-(1,2, ?-(1,3 and ?-(1,5 disaccharides including sucrose, highlighting their substrate ambiguity. While Ima1p and Ima2p presented almost identical characteristics, our results nevertheless showed many singularities within this protein family. In particular, Ima3p presented lower activities and thermostability than Ima2p despite only three different amino acids between the sequences of these two isoforms. The Ima3p_R279Q variant recovered activity levels of Ima2p, while the Leu-to-Pro substitution at position 240 significantly increased the stability of Ima3p and supported the role of prolines in thermostability. The most distant protein, Ima5p, presented the lowest optimal temperature and was also extremely sensitive to temperature. Isomaltose hydrolysis by Ima5p challenged previous conclusions about the requirement of specific amino acids for determining the specificity for ?-(1,6 substrates. We finally found a mixed inhibition by maltose for Ima5p while, contrary to a previous work, Ima1p inhibition by maltose was competitive at very low isomaltose concentrations and uncompetitive as the substrate concentration increased. Altogether, this work illustrates that a gene family encoding proteins with strong sequence similarities can lead to enzyme with notable differences in biochemical and enzymological properties.

  5. Saccharomyces cerevisiae UE-ME3 is a good strain for isoproturon biorremediation?

    OpenAIRE

    Candeias, M; I. Alves-Pereira; Ferreira, R.

    2010-01-01

    Isoproturon, an herbicide of pre- and pos-emergence of Autumn-Winter crops, persists occasionally in soil, groundwater and biological systems at levels above those established by European Directives. Saccharomyces cerevisiae UE-ME3 exposed in stationary phase to 50 and 100 mM isoproturon exhibit growth rates higher than control or exposed cells to 5 and 25 mM of this phenylurea. However, in S.cerevisiae UE-ME3 grown in the presence of 5 mM isoproturon, were observed a decrease of ...

  6. The acyl dihydroxyacetone phosphate pathway enzymes for glycerolipid biosynthesis are present in the yeast Saccharomyces cerevisiae.

    OpenAIRE

    Racenis, P V; Lai, J L; Das, A. K.; Mullick, P C; Hajra, A K; Greenberg, M L

    1992-01-01

    The presence of the acyl dihydroxyacetone phosphate (acyl DHAP) pathway in yeasts was investigated by examining three key enzyme activities of this pathway in Saccharomyces cerevisiae. In the total membrane fraction of S. cerevisiae, we confirmed the presence of both DHAP acyltransferase (DHAPAT; Km = 1.27 mM; Vmax = 5.9 nmol/min/mg of protein) and sn-glycerol 3-phosphate acyltransferase (GPAT; Km = 0.28 mM; Vmax = 12.6 nmol/min/mg of protein). The properties of these two acyltransferases are...

  7. Improved ethanol production from whey Saccharomyces cerevisiae using permeabilized cells of Kluyveromyces marxianus

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Biochemical Technology; Tomaska, M. [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Biochemical Technology; Kanuch, J. [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Biochemical Technology; Sturdik, E. [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Biochemical Technology

    1995-12-31

    Permeabilized cells of Kluyveromyces marxianus CCY eSY2 were tested as the source of lactase in the ethanol fermentation of concentrated deproteinized whey (65-70 g/l lactose) by Saccharomyces cerevisiae CCY 10-13-14. Rapid lactose hydrolysis by small amounts of permeabilized cells following the fermentation of released glucose and galactose by S. cerevisiae resulted in a twofold enhancement of the overall volumetric productivity (1.03 g/lxh), compared to the fermentation in which the lactose was directly fermented by K. marxianus. (orig.)

  8. Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals

    DEFF Research Database (Denmark)

    Borodina, Irina; Nielsen, Jens

    2014-01-01

    Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology and the advances in yeast strain engineering will stimulate development of novel yeast-based processes for chemicals production.

  9. Effects of nickel on the mineral composition of Fleischmann’s yeast (Saccharomyces cerevisiae) Efeitos do niquel na composição mineral da levedura Fleischmann (Saccharomyces cerevisiae)

    OpenAIRE

    Samuel Mariano-da-Silva; Joys Dias de Assis Brait; Luiz Henrique Poleto Angeloni; Fabiana Maria de Siqueira Mariano-da-Silva; César Augusto Oliveira Leite; Paula Braga

    2007-01-01

    Sugar cane juice containing 12% (w.w -1) of total reducing sugars and 0.0 to 5.0 mmol of nickel L-1, with pH ranging from 3.5 to 6.5, was inoculated with Fleischmann’s yeast (Saccharomyces cerevisiae) (10% w.w -1). Six hours after fermentation, the yeast’s cellular viability and trehalose content were evaluated. The resulting must was centrifuged and the raw yeast was analyzed by atomic absorption spectroscopy to evaluate the intracellular levels of calcium, copper, iron, magnesium, manganese...

  10. Finding of thiosulfate pathway for synthesis of organic sulfur compounds in Saccharomyces cerevisiae and improvement of ethanol production.

    Science.gov (United States)

    Funahashi, Eri; Saiki, Kyohei; Honda, Kurara; Sugiura, Yuki; Kawano, Yusuke; Ohtsu, Iwao; Watanabe, Daisuke; Wakabayashi, Yukari; Abe, Tetsuya; Nakanishi, Tsuyoshi; Suematsu, Makoto; Takagi, Hiroshi

    2015-12-01

    We found that Saccharomyces cerevisiae utilizes thiosulfate as a sole sulfur source. The energetically-favored thiosulfate rather than sulfate as sulfur sources is also more effective for improving growth and ethanol-production rate in S. cerevisiae due to high levels of intracellular NADPH during thiosulfate utilization. PMID:26188417

  11. Integrated phospholipidomics and transcriptomics analysis of Saccharomyces cerevisiae with enhanced tolerance to a mixture of acetic acid, furfural, and phenol

    Science.gov (United States)

    A mixture of acetic acid, furfural and phenol (AFP), three representative lignocellulose derived inhibitors, significantly inhibited the growth and bioethanol production of Saccharomyces cerevisiae. In order to uncover mechanisms behind the enhanced tolerance of an inhibitor-tolerant S.cerevisiae s...

  12. Tomato QM-Like Protein Protects Saccharomyces cerevisiae Cells against Oxidative Stress by Regulating Intracellular Proline Levels

    OpenAIRE

    Chen, Changbin; Wanduragala, Srimevan; Becker, Donald F; Dickman, Martin B.

    2006-01-01

    Exogenous proline can protect cells of Saccharomyces cerevisiae from oxidative stress. We altered intracellular proline levels by overexpressing the proline dehydrogenase gene (PUT1) of S. cerevisiae. Put1p performs the first enzymatic step of proline degradation in S. cerevisiae. Overexpression of Put1p results in low proline levels and hypersensitivity to oxidants, such as hydrogen peroxide and paraquat. A put1-disrupted yeast mutant deficient in Put1p activity has increased protection from...

  13. Digestibility and nutrient intake in Mangalarga Marchador mares supplemented with Saccharomyces cerevisiae during aerobic training

    Directory of Open Access Journals (Sweden)

    Tiago Resende Garcia

    2014-09-01

    Full Text Available The study evaluated the effect of yeast supplementation on the digestibility and intake of nutrients of Mangalarga Marchador horses in training. Fourteen Mangalarga Marchador mares were divided into two groups: Probiotic (horses supplemented with 20 g of Saccharomyces cerevisiae daily and Control. The diet consisted of commercial concentrate and roughage in the ratio of 50:50. The mares were trained for six weeks, Monday to Saturday, and the exercise performed daily alternating work on a treadmill and automatic walker. Nutrient digestibility was assessed using the indicator LIPE® (6 days end fecal collection was performed for five days. Was analyzed DM, NDF, ADF, CP, GE, hemicelluloses and dry matter intake. There was not difference (P>0,05 in any of the variables analyzed. Supplementation with 20 g of Saccharomyces cerevisiae does not affect the digestibility and nutrient intake in mares Mangalarga Marchador submitted six weeks of aerobic training.

  14. Crystallization and Preliminary X-ray Diffraction Analysis of motif N from Saccharomyces cerevisiae Dbf4

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, L.; Duong, A; Prasad, A; Duncker, B; Guarne, A

    2009-01-01

    The Cdc7-Dbf4 complex plays an instrumental role in the initiation of DNA replication and is a target of replication-checkpoint responses in Saccharomyces cerevisiae. Cdc7 is a conserved serine/threonine kinase whose activity depends on association with its regulatory subunit, Dbf4. A conserved sequence near the N-terminus of Dbf4 (motif N) is necessary for the interaction of Cdc7-Dbf4 with the checkpoint kinase Rad53. To understand the role of the Cdc7-Dbf4 complex in checkpoint responses, a fragment of Saccharomyces cerevisiae Dbf4 encompassing motif N was isolated, overproduced and crystallized. A complete native data set was collected at 100 K from crystals that diffracted X-rays to 2.75 {angstrom} resolution and structure determination is currently under way.

  15. Effect of Reserve Carbohydrates on Oxidative Stress in Yeast Saccharomyces cerevisiae Y6210

    Directory of Open Access Journals (Sweden)

    Smita Kanwal

    2011-11-01

    Full Text Available The aim of this study is investigate the role of reserve carbohydrates, trehalose and glycogen in DEM (Diethyl Maleate induced oxidative stress in yeast Saccharomyces cerevisiae Y6210. Trehalose and glycogen accumulated in Saccharomyces cerevisiae, when growth conditions deteriorate. Yeast cells were subjected to oxidative stress for different time periods (0, 30, 60 and 120 min to evaluate the role of trehalose, glycogen and trehalase. There was no change in the level of trehalose while the content of glycogen increased during the oxidative stress. The time dependent modulation in the activities of trehalase and invertase was observed under oxidative stress. It has been suggested that glycogen serving as a protectant during oxidative stress not trehalose.

  16. [Construction of recombinant Saccharomyces cerevisiae producing 1,3-propanediol by one step method].

    Science.gov (United States)

    Ma, Zheng; Rao, Zhi-ming; Shen, Wei; Fang, Hui-ying; Zhuge, Jian

    2007-08-01

    1,3-Propanediol is one of the most important industrial chemicals for its highly desired properties and its wide applications as a key component of an emerging polymer business. Biological production of 1,3-propanediol has been a novel and competitive way. In our previous job, the gene dahB encoding for glycerol dehydratase from Klebsiella and the gene yqhD encoding for 1,3-propanediol oxidoreductase isoenzyme from E. coli were cloned respectively. The two genes were then tandemly ligated and expressed successfully in E. coli. The recombinant E. coli strain could produce 1,3-propanediol from D-glycerol. In the current research, the expression vectors including pGAPZB-yqhD, pGAPZB-dhaB and pYX212-zeocin-pGAP-yqhD-pGAP-dhaB were furtherly constructed on the basis of our previous job. Then the vector pYX212-zeocin-pGAP-yqhD-pGAP-dhaB was introduced into Saccharomyces cerevisiae W303-1A using LiAc transformation method successfully. D-glucose is used as substrate to produce 1,3-propanediol with the recombinant strain after fermentation for 72h. SDS-PAGE analysis showed recombinant products at about 61kD, 43kD, 21kD, 15kD, consistent with the molecular weight from the report. The specific enzymatic activity of the glycerol dehydratase and 1,3-propanediol oxidoreductase isoenzyme of the recombinant yeast strain S. cerevisiae W303-1A/pYX2l2-zeocin-pGAP-yqhD-pGAP-dhaB were 24U/mg protein and 15U/mg protein, respectively, while those of the control were undetectable. In contrast to the wild strain without 1,3-propanediol output, 1,3-propanediol concentration of the recombinant yeast strain S. cerevisiae W303-1A/pYX212-zeocin-pGAP-yqhD-pGAP-dhaB reaches about 1.5g/L. The above results showed that the engineered S. cerevisiae strain which can convert the D-glucose as substrate to produce 1,3-propanediol by one-step fermentation was constructed successfully. This accomplishment bodes well for future construction of recombinant yeast strain which could overproduce 1,3-propanediol with the lower cost feedstock D-glucose by introducing the two genes yqhD and dhaB into the yeast strain overproducing glycerol with D-glucose (e.g. Candida glycerinogenes WL2002-5, which is capable of producing glycerol more than 120g/L with D-glucose as substrate and has been used for the commercial production of glycerol). PMID:17944357

  17. Predicción del contenido intracelular de trehalosa en el proceso de producción de biomasa de Saccharomyces cerevisiae

    OpenAIRE

    J. S. Aranda; A. I. Cabrera; J. I. Chairez

    2008-01-01

    La trehalosa es un carbohidrato dimérico componente de la levadura de panificación Saccharomyces cerevisiae, y es considerado como indicador de la capacidad fermentativa y de la viabilidad de las células. En procesos de producción de levadura, se busca inducir una acumulación intracelular de trehalosa. Por ser un compuesto citoplásmico, la cuantificación de la trehalosa requiere de tomas de muestra y de métodos analíticos posteriores. Así, el conocimiento del contenido citoplásmic...

  18. Robust Metabolic Responses to Varied Carbon Sources in Natural and Laboratory Strains of Saccharomyces cerevisiae

    OpenAIRE

    Van Voorhies, Wayne A.

    2012-01-01

    Understanding factors that regulate the metabolism and growth of an organism is of fundamental biologic interest. This study compared the influence of two different carbon substrates, dextrose and galactose, on the metabolic and growth rates of the yeast Saccharomyces cerevisiae. Yeast metabolic and growth rates varied widely depending on the metabolic substrate supplied. The metabolic and growth rates of a yeast strain maintained under long-term laboratory conditions was compared to strain i...

  19. High Osmolarity Extends Life Span in Saccharomyces cerevisiae by a Mechanism Related to Calorie Restriction

    OpenAIRE

    Kaeberlein, Matt; Andalis, Alex A; Fink, Gerald R; Guarente, Leonard

    2002-01-01

    Calorie restriction (CR) extends life span in many different organisms, including mammals. We describe here a novel pathway that extends the life span of Saccharomyces cerevisiae mother cells but does not involve a reduction in caloric content of the media, i.e., there is growth of yeast cells in the presence of a high concentration of external osmolytes. Like CR, this longevity-promoting response to high osmolarity requires SIR2, suggesting a common mechanism of life span regulation. Genetic...

  20. THE EFFECT OF PHOSPHATE ACCUMULATION ON METAL ION HOMEOSTASIS IN SACCHAROMYCES CEREVISIAE

    OpenAIRE

    Rosenfeld, Leah; Reddi, Amit R.; Leung, Edison; Aranda, Kimberly; Jensen, Laran T.; Culotta, Valeria C.

    2010-01-01

    Much of what is currently understood about the cell biology of metals involves their interactions with proteins. By comparison, little is known about metal interactions with intracellular inorganic compounds such as phosphate. Here we examined the role of phosphate in metal metabolism in vivo by genetically perturbing the phosphate content of Saccharomyces cerevisiae cells. Yeast pho80 mutants cannot sense phosphate and have lost control of phosphate uptake, storage and metabolism. We report ...

  1. Rapid method for isolation and screening of cytochrome c oxidase-deficient mutants of Saccharomyces cerevisiae.

    OpenAIRE

    McEwen, J.E; Cameron, V L; Poyton, R. O.

    1985-01-01

    We describe here a new method for the specific isolation of cytochrome c oxidase-deficient mutants of Saccharomyces cerevisiae. One unique feature of the method is the use of tetramethyl-p-phenylenediamine as a cytochrome c oxidase activity stain for yeast colonies. The staining of yeast colonies by tetramethyl-p-phenylenediamine is dependent upon a functional cytochrome c oxidase and is unaffected by other lesions in respiration. Since the tetramethyl-p-phenylenediamine colony staining react...

  2. Shelterin-Like Proteins and Yku Inhibit Nucleolytic Processing of Saccharomyces cerevisiae Telomeres

    OpenAIRE

    Bonetti, Diego; Clerici, Michela; Anbalagan, Savani; Martina, Marina; Lucchini, Giovanna; Longhese, Maria Pia

    2010-01-01

    Eukaryotic cells distinguish their chromosome ends from accidental DNA double-strand breaks (DSBs) by packaging them into protective structures called telomeres that prevent DNA repair/recombination activities. Here we investigate the role of key telomeric proteins in protecting budding yeast telomeres from degradation. We show that the Saccharomyces cerevisiae shelterin-like proteins Rif1, Rif2, and Rap1 inhibit nucleolytic processing at both de novo and native telomeres during G1 and G2 cel...

  3. Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals

    DEFF Research Database (Denmark)

    Borodina, Irina; Nielsen, Jens

    2014-01-01

    Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic aci...

  4. Increased isobutanol production in Saccharomyces cerevisiae by overexpression of genes in valine metabolism

    DEFF Research Database (Denmark)

    Chen, Xiao; Nielsen, Kristian Fog; Borodina, Irina; Kielland-Brandt, Morten; Karhumaa, Kaisa

    2011-01-01

    BACKGROUND: Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. Furthermore, the branched-chain structure of isobutanol gives a higher octane number than the isomeric n-butanol. Saccharomyces cerevisiae was chosen as the production host because of its relative tolerance to alcohols, robustness in industrial fermentations, and the possibility for future combination of isobutanol production with fermentation of lignocellulosic materials. RESUL...

  5. Engineering of Saccharomyces cerevisiae for Efficient Anaerobic Alcoholic Fermentation of L-Arabinose:

    OpenAIRE

    Wisselink, H.W.; Toirkens, M.J.; del Rosario Franco Berriel, M.; Winkler, A.A.; van Dijken, J P; Pronk, J T; Van Maris, A.J.A.

    2007-01-01

    For cost-effective and efficient ethanol production from lignocellulosic fractions of plant biomass, the conversion of not only major constituents, such as glucose and xylose, but also less predominant sugars, such as L-arabinose, is required. Wild-type strains of Saccharomyces cerevisiae, the organism used in industrial ethanol production, cannot ferment xylose and arabinose. Although metabolic and evolutionary engineering has enabled the efficient alcoholic fermentation of xylose under anae...

  6. Transcriptional Response of Saccharomyces cerevisiae to Different Nitrogen Concentrations during Alcoholic Fermentation? †

    OpenAIRE

    Mendes-Ferreira, A.; Del Olmo, M.; García-Martínez, J.; Jiménez-Martí, E.; Mendes-Faia, A.; Pérez-Ortín, J E; Leão, C.

    2007-01-01

    Gene expression profiles of a wine strain of Saccharomyces cerevisiae PYCC4072 were monitored during alcoholic fermentations with three different nitrogen supplies: (i) control fermentation (with enough nitrogen to complete sugar fermentation), (ii) nitrogen-limiting fermentation, and (iii) the addition of nitrogen to the nitrogen-limiting fermentation (refed fermentation). Approximately 70% of the yeast transcriptome was altered in at least one of the fermentation stages studied, revealing t...

  7. Impact of assimilable nitrogen availability in glucose uptake kinetics in Saccharomyces cerevisiae during alcoholic fermentation

    OpenAIRE

    Palma Margarida; Madeira Sara; Mendes-Ferreira Ana; Sá-Correia Isabel

    2012-01-01

    Abstract Background The expression and activity of the different Saccharomyces cerevisiae hexose uptake systems (Hxt) and the kinetics of glucose uptake are considered essential to industrial alcoholic fermentation performance. However, the dynamics of glucose uptake kinetics during the different stages of fermentation, depending on glucose and nitrogen availability, is very poorly characterized. The objective of the present work was to examine thoroughly the alterations occurring in glucose ...

  8. Engineering of Saccharomyces cerevisiae for Efficient Anaerobic Alcoholic Fermentation of l-Arabinose?

    OpenAIRE

    Wisselink, H. Wouter; Toirkens, Maurice J.; del Rosario Franco Berriel, M.; Winkler, Aaron A.; Van Dijken, Johannes P.; Pronk, Jack T; van Maris, Antonius J.A.

    2007-01-01

    For cost-effective and efficient ethanol production from lignocellulosic fractions of plant biomass, the conversion of not only major constituents, such as glucose and xylose, but also less predominant sugars, such as l-arabinose, is required. Wild-type strains of Saccharomyces cerevisiae, the organism used in industrial ethanol production, cannot ferment xylose and arabinose. Although metabolic and evolutionary engineering has enabled the efficient alcoholic fermentation of xylose under anae...

  9. Ethanol production using Saccharomyces cerevisiae cells immobilised on corn stem ground tissue

    OpenAIRE

    Vu?urovi? Vesna M.; Razmovski Radojka N.; Popov Stevan D.

    2009-01-01

    Cell immobilisation in alcoholic fermentation has been extensively studied during the past few decades because of its technical and economical advantages over those of free cell systems. A biocatalyst was prepared by immobilising a commercial Saccharomyces cerevisiae strain (baker yeast) on corn stem ground tissue for use in alcoholic fermentation. For this purpose, the yeast cells were submitted to the batch tests 'in situ' adsorption onto pieces of the corn stem ground tissue. Cells immobil...

  10. Fungicide residues in grapes determined the dynamics of Saccharomyces cerevisiae strains during spontaneous wine fermentation

    OpenAIRE

    ?uš Franc; ?adež Neža J.; Raspor Peter I.

    2011-01-01

    Impact of three fungicides against B. cinerea (iprodione, pyrimethanil and f ludioxonil plus cyprodinil) on the population of Saccharomyces cerevisiae strains during the spontaneous alcoholic fermentation was studied. With regard to the use of fungicides in the vineyard at two stages of the grapevine growth we followed four different spontaneous fermentations: control, iprodione, pyrimethanil and f ludioxonil plus cyprodinil. The fungicide residues in the grapes were determined by GC/MS...

  11. Cloning and expression of the bacillus licheniformis a-amylase gene in saccharomyces cerevisiae

    OpenAIRE

    McMahon, Hugh

    1995-01-01

    The a-amylase gene from Bacillus licheniformis together with its signal peptide seguence was cloned into a yeast expression vector under the control of the yeast ADH1 promoter and terminator. The resulting construct, pAAMY, when introduced into Saccharomyces cerevisiae cells which when subsequently grown under pH-controlled conditions, produced active a-amylase enzyme. At least 95% of the recombinant amylase is located extracellurarly. Temperature sensitive yeast mutants defective in the s...

  12. Protein characterization of Saccharomyces cerevisiae RNA polymerase II after in vivo cross-linking

    OpenAIRE

    Tardiff, Daniel F.; Abruzzi, Katharine C; ROSBASH, MICHAEL

    2007-01-01

    To characterize proteins associated with active transcription complexes, we purified RNA polymerase II (pol II) from Saccharomyces cerevisiae after fixing live cells with formaldehyde. The approach mimics ChIP and requires solubilizing cross-linked complexes with sonication. Pol II was affinity-purified, and associated proteins were identified by MS. Several classes of proteins depended on cross-linking, including Mediator, general transcription factors, elongation factors, ribonucleoprotein ...

  13. Physiological behaviour of saccharomyces cerevisiae under increased air and oxygen pressures

    OpenAIRE

    Pinheiro, Rita; Belo, Isabel; M. Mota

    1997-01-01

    Saccharomyces cerevisiae, in a pressure batch reactor, coped with higher air (1.2–3 bar) pressures better than with pure oxygen pressures (1.2–3 bar) for an equivalent dissolved oxygen concentration. However, pure oxygen pressure enhanced ethanol production. Both pressures did not influence the type of metabolism followed by the organism which was always oxidoreductive. Growth was inhibited with the increase of air and pure oxygen pressure and almost completely inhibited with 8 bar of pure ox...

  14. Regulation of hydrogen sulfide liberation in wine-producing Saccharomyces cerevisiae strains by assimilable nitrogen.

    OpenAIRE

    Jiranek, V; Langridge, P.; Henschke, P A

    1995-01-01

    Saccharomyces cerevisiae wine-producing yeast cultures grown under model winemaking conditions could be induced to liberate hydrogen sulfide (H2S) by starvation for assimilable nitrogen. The amount of H2S produced was dependent on the yeast strain, the sulfur precursor compound, the culture growth rate, and the activity of the sulfite reductase enzyme (EC 1.8.1.2) immediately before nitrogen depletion. Increased H2S formation relative to its utilization by metabolism was not a consequence of ...

  15. A novel Saccharomyces cerevisiae secretory mutant possesses a thermolabile phosphomannose isomerase.

    OpenAIRE

    Payton, M. A.; Rheinnecker, M; Klig, L S; DeTiani, M; Bowden, E

    1991-01-01

    A temperature-sensitive mutant of Saccharomyces cerevisiae was identified which at the restrictive temperature of 37 degrees C is unable to secrete a number of cell wall-associated proteins and thus resembles previously reported sec mutants. In contrast to other sec mutants, however, both the temperature-sensitive growth and the secretion defects can be repaired by the addition of D-mannose to growth media. We show that the mutant possesses a single, apparently recessive mutation which leads ...

  16. Recombinant Production of Human Aquaporin-1 to an Exceptional High Membrane Density in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Bomholt, Julie; Hélix-Nielsen, Claus; Scharff-Poulsen, Peter; Pedersen, Per Amstrup

    2013-01-01

    In the present paper we explored the capacity of yeast Saccharomyces cerevisiae as host for heterologous expression of human Aquaporin-1. Aquaporin-1 cDNA was expressed from a galactose inducible promoter situated on a plasmid with an adjustable copy number. Human Aquaporin-1 was C-terminally tagged with yeast enhanced GFP for quantification of functional expression, determination of sub-cellular localization, estimation of in vivo folding efficiency and establishment of a purification protocol....

  17. Red Fluorescent Protein (DsRed) as a Reporter in Saccharomyces cerevisiae

    OpenAIRE

    Rodrigues, Fernando; van Hemert, Martijn; Steensma, H. Yde; Côrte-Real, Manuela; Leão, Cecíla

    2001-01-01

    We describe the utilization of a red fluorescent protein (DsRed) as an in vivo marker for Saccharomyces cerevisiae. Clones expressing red and/or green fluorescent proteins with both cytoplasmic and nuclear localization were obtained. A series of vectors are now available which can be used to create amino-terminal (N-terminal) and carboxyl-terminal (C-terminal) fusions with the DsRed protein.

  18. The daughters of Saccharomyces cerevisiaeRAS2val19 mutant are born old.

    Czech Academy of Sciences Publication Activity Database

    Pichová, Alena; Sigler, Karel

    Bratislava : SAS, 2007, s. 80-80. ISSN 1336-4839. [Annual Conference on Yeasts /35./. Smolenice (SK), 16.05.2007-18.05.2007] R&D Projects: GA ?R GA301/03/0289; GA ?R GA301/07/0339; GA MŠk 1M0570 Institutional research plan: CEZ:AV0Z50200510 Keywords : saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  19. Diversion of flux toward sesquiterpene production in Saccharomyces cerevisiae by fusion of host and heterologous enzymes

    DEFF Research Database (Denmark)

    Albertsen, Line; Chen, Yun; Bach, Lars Stougaard; Rattleff, Stig; Maury, Jerome; Pedersen, Susanne Brix; Nielsen, Jens; Mortensen, Uffe Hasbro

    2011-01-01

    The ability to transfer metabolic pathways from the natural producer organisms to the well-characterized cell factory Saccharomyces cerevisiae is well documented. However, as many secondary metabolites are produced by collaborating enzymes assembled in complexes, metabolite production in yeast may be limited by the inability of the heterologous enzymes to collaborate with the native yeast enzymes. This may cause loss of intermediates by diffusion or degradation or due to conversion of the interm...

  20. ABC Transporter Pdr10 Regulates the Membrane Microenvironment of Pdr12 in Saccharomyces cerevisiae

    OpenAIRE

    Rockwell, Nathan C.; Wolfger, Hubert; Kuchler, Karl; Thorner, Jeremy

    2009-01-01

    The eukaryotic plasma membrane exhibits both asymmetric distribution of lipids between the inner and the outer leaflet and lateral segregation of membrane components within the plane of the bilayer. In budding yeast (Saccharomyces cerevisiae), maintenance of leaflet asymmetry requires P-type ATPases, which are proposed to act as inward-directed lipid translocases (Dnf1, Dnf2, and the associated protein Lem3), and ATP-binding cassette (ABC) transporters, which are proposed to act as outward-di...

  1. Ssd1 Is Required for Thermotolerance and Hsp104-Mediated Protein Disaggregation in Saccharomyces cerevisiae?

    OpenAIRE

    Mir, Snober S.; Fiedler, David; Cashikar, Anil G.

    2008-01-01

    In the budding yeast Saccharomyces cerevisiae, the Hsp104-mediated disaggregation of protein aggregates is essential for thermotolerance and to facilitate the maintenance of prions. In humans, protein aggregation is associated with neuronal death and dysfunction in many neurodegenerative diseases. Mechanisms of aggregation surveillance that regulate protein disaggregation are likely to play a major role in cell survival after acute stress. However, such mechanisms have not been studied. In a ...

  2. Towards fermentation of galacturonic acid-containing feedstocks with Saccharomyces cerevisiae:

    OpenAIRE

    Huisjes, E.H.

    2013-01-01

    The ambition to reduce our current dependence on fossil transportation fuels has driven renewed interest in bioethanol. Pectin-rich feedstocks like sugar beet pulp and citrus peel, which are currently sold as cattle feed, are promising raw materials for the production of bioethanol. This thesis explores the challenges related to the fermentation of pectin-rich hydrolysates with Saccharomyces cerevisiae. Galacturonic acid is a major constituent of pectin-rich hydrolysates. Achieving efficient ...

  3. Saccharomyces cerevisiae Mutants Resistant to Catabolite Repression: Use in Cheese Whey Hydrolysate Fermentation

    OpenAIRE

    Bailey, Richard B.; Benitez, Tahia; Woodward, Anne

    1982-01-01

    Mutants of an industrial-type strain of Saccharomyces cerevisiae which rapidly and completely fermented equimolar mixtures of glucose and galactose to ethanol were isolated. These mutants fell into two general phenotypic classes based upon their fermentation kinetics and enzyme induction patterns. One class apparently specifically effects the utilization of galactose and allows sequential utilization of first glucose and then galactose in an anaerobic fermentation. The second class of mutants...

  4. Self-surface assembly of cellulosomes with two miniscaffoldins on Saccharomyces cerevisiae for cellulosic ethanol production

    OpenAIRE

    Fan, Li-Hai; ZHANG, ZI-JIAN; Yu, Xiao-Yu; Xue, Ya-Xu; Tan, Tian-Wei

    2012-01-01

    Yeast to directly convert cellulose and, especially, the microcrystalline cellulose into bioethanol, was engineered through display of minicellulosomes on the cell surface of Saccharomyces cerevisiae. The construction and cell surface attachment of cellulosomes were accomplished with two individual miniscaffoldins to increase the display level. All of the cellulases including a celCCA (endoglucanase), a celCCE (cellobiohydrolase), and a Ccel_2454 (?-glucosidase) were cloned from Clostridium c...

  5. Improvement of ethanol production by ethanol-tolerant Saccharomyces cerevisiae UVNR56

    OpenAIRE

    Thammasittirong, Sutticha Na-Ranong; Thirasaktana, Thanawan; Thammasittirong, Anon; Srisodsuk, Malee

    2013-01-01

    Ethanol tolerance is one of the important characteristics of ethanol-producing yeast. This study focused on the improvement of ethanol tolerance of Saccharomyces cerevisiae NR1 for enhancing ethanol production by random UV-C mutagenesis. One ethanol-tolerant mutant, UVNR56, displayed a significantly improved ethanol tolerance in the presence of 15% (v/v) ethanol and showed a considerably higher viability during ethanol fermentation from sugarcane molasses and sugarcane molasses with initial e...

  6. Adaptation of a flocculent Saccharomyces cerevisiae strain to lignocellulosic inhibitors by cell recycle batch fermentation

    OpenAIRE

    Landaeta, R.; Aroca, G.; Acevedo, F.; Teixeira, J. A.; Mussatto, Solange I.

    2013-01-01

    The ethanol production from lignocellulosic feedstocks is considered a promising strategy to increase global production of biofuels without impacting food supplies. However, some compounds released during the hydrolysis of lignocellulosic materials are toxic for the microbial metabolism, causing low ethanol yield and productivity during the fermentation. As an attempt to overcome this problem, the present study evaluated the adaptation of a flocculent strain of Saccharomyces cerevisiae (NRRL ...

  7. Inhibition of mycotoxin-producing Aspergillus nomius vsc 23 by lactic acid bacteria and Saccharomyces cerevisiae

    OpenAIRE

    Muñoz, R.; Arena, M.E.; Silva, J.; González, S. N.

    2010-01-01

    The effect of different fermenting microorganisms on growth of a mycotoxin- producing Aspergillus nomius was assayed. Two lactic acid bacteria, Lactobacillus fermentum and Lactobacillus rhamnosus, and Saccharomyces cerevisiae, all of which are widely used in fermentation and preservation of food, were assayed on their fungus inhibitory properties. Assays were carried out by simultaneous inoculation of one of the possible inhibiting microorganisms and the fungus or subsequent inoculation of on...

  8. Salt tolerance and methionine biosynthesis in Saccharomyces cerevisiae involve a putative phosphatase gene.

    OpenAIRE

    Gläser, H U; Thomas, D.; Gaxiola, R.; Montrichard, F; Surdin-Kerjan, Y; Serrano, R

    1993-01-01

    The progressive salinization of irrigated land poses a threat to the future of agriculture in arid regions. The identification of crucial metabolic steps in salt tolerance is important for the understanding of stress physiology and may provide the tools for its genetic engineering. In the yeast Saccharomyces cerevisiae we have isolated a gene, HAL2, which upon increase in gene dosage improves growth under NaCl and LiCl stresses. The HAL2 protein is homologous to inositol phosphatases, enzymes...

  9. Engineering Redox Cofactor Regeneration for Improved Pentose Fermentation in Saccharomyces cerevisiae

    OpenAIRE

    Verho, Ritva; Londesborough, John; Penttilä, Merja; Richard, Peter

    2003-01-01

    Pentose fermentation to ethanol with recombinant Saccharomyces cerevisiae is slow and has a low yield. A likely reason for this is that the catabolism of the pentoses d-xylose and l-arabinose through the corresponding fungal pathways creates an imbalance of redox cofactors. The process, although redox neutral, requires NADPH and NAD+, which have to be regenerated in separate processes. NADPH is normally generated through the oxidative part of the pentose phosphate pathway by the action of glu...

  10. Molecular and physiological approaches towards the characterisation of glycerol transport in Saccharomyces Cerevisiae

    OpenAIRE

    Oliveira, Rui Pedro Soares de

    2003-01-01

    A adaptação fisiológica de células de Saccharomyces cerevisiae a condições de stresse salino envolve a acumulação intracelular de glicerol como soluto compatível. A concentração citoplasmática de glicerol é regulada permitindo a manutenção do equilíbrio da actividade da água entre o compartimento celular e o meio externo. Em células cultivadas em meios contendo açúcares fermentescíveis, tal como na maior parte dos habitats naturais de levedura, o glicerol é produzido por red...

  11. Catalase Overexpression Reduces Lactic Acid-Induced Oxidative Stress in Saccharomyces cerevisiae:

    OpenAIRE

    Abbott, D.A.; Suir, E.; Duong, G.H.; de Hulster, E; Pronk, J T; Van Maris, A.J.A.

    2009-01-01

    Industrial production of lactic acid with the current pyruvate decarboxylase-negative Saccharomyces cerevisiae strains requires aeration to allow for respiratory generation of ATP to facilitate growth and, even under nongrowing conditions, cellular maintenance. In the current study, we observed an inhibition of aerobic growth in the presence of lactic acid. Unexpectedly, the cyb2{Delta} reference strain, used to avoid aerobic consumption of lactic acid, had a specific growth rate of 0.25 h–1 ...

  12. ROX1 and ERG Regulation in Saccharomyces cerevisiae: Implications for Antifungal Susceptibility

    OpenAIRE

    Henry, Karl W.; Nickels, Joseph T.; Edlind, Thomas D.

    2002-01-01

    Yeasts respond to treatment with azoles and other sterol biosynthesis inhibitors by upregulating the expression of the ERG genes responsible for ergosterol production. Previous studies on Saccharomyces cerevisiae implicated the ROX1 repressor in ERG regulation. We report that ROX1 deletion resulted in 2.5- to 16-fold-lower susceptibilities to azoles and terbinafine. In untreated cultures, ERG11 was maximally expressed in mid-log phase and expression decreased in late log phase, while the inve...

  13. Requirement for ESP1 in the nuclear division of Saccharomyces cerevisiae.

    OpenAIRE

    McGrew, J T; Goetsch, L; Byers, B; Baum, P.

    1992-01-01

    Mutations in the ESP1 gene of Saccharomyces cerevisiae disrupt normal cell-cycle control and cause many cells in a mutant population to accumulate extra spindle pole bodies. To determine the stage at which the esp1 gene product becomes essential for normal cell-cycle progression, synchronous cultures of ESP1 mutant cells were exposed to the nonpermissive temperature for various periods of time. The mutant cells retained viability until the onset of mitosis, when their viability dropped marked...

  14. Saccharomyces Cerevisiae Cell Wall Components as Tools for Ochratoxin A Decontamination

    OpenAIRE

    Piotrowska, Ma?gorzata; Masek, Anna

    2015-01-01

    The aim of this study was to evaluate the usefulness of Saccharomyces cerevisiae cell wall preparations in the adsorption of ochratoxin A (OTA). The study involved the use of a brewer’s yeast cell wall devoid of protein substances, glucans obtained by water and alkaline extraction, a glucan commercially available as a dietary supplement for animals and, additionally, dried brewer’s yeast for comparison. Fourier Transform Infrared (FTIR) analysis of the obtained preparations showed bands chara...

  15. Dysfunctional Mitochondria Modulate cAMP-PKA Signaling and Filamentous and Invasive Growth of Saccharomyces cerevisiae

    OpenAIRE

    Aun, Anu; Tamm, Tiina; Sedman, Juhan

    2013-01-01

    Mitochondrial metabolism is targeted by conserved signaling pathways that mediate external information to the cell. However, less is known about whether mitochondrial dysfunction interferes with signaling and thereby modulates the cellular response to environmental changes. In this study, we analyzed defective filamentous and invasive growth of the yeast Saccharomyces cerevisiae strains that have a dysfunctional mitochondrial genome (rho mutants). We found that the morphogenetic defect of rho...

  16. Functional Assembly of Minicellulosomes on the Saccharomyces cerevisiae Cell Surface for Cellulose Hydrolysis and Ethanol Production?

    OpenAIRE

    Tsai, Shen-Long; Oh, Jeongseok; Singh, Shailendra; Chen, Ruizhen; Chen, Wilfred

    2009-01-01

    We demonstrated the functional display of a miniscaffoldin on the Saccharomyces cerevisiae cell surface consisting of three divergent cohesin domains from Clostridium thermocellum (t), Clostridium cellulolyticum (c), and Ruminococcus flavefaciens (f). Incubation with Escherichia coli lysates containing an endoglucanase (CelA) fused with a dockerin domain from C. thermocellum (At), an exoglucanase (CelE) from C. cellulolyticum fused with a dockerin domain from the same species (Ec), and an end...

  17. A role for MMS4 in the processing of recombination intermediates during meiosis in Saccharomyces cerevisiae.

    OpenAIRE

    de los Santos, T; Loidl, J.; Larkin, B; Hollingsworth, N. M.

    2001-01-01

    The MMS4 gene of Saccharomyces cerevisiae was originally identified due to its sensitivity to MMS in vegetative cells. Subsequent studies have confirmed a role for MMS4 in DNA metabolism of vegetative cells. In addition, mms4 diploids were observed to sporulate poorly. This work demonstrates that the mms4 sporulation defect is due to triggering of the meiotic recombination checkpoint. Genetic, physical, and cytological analyses suggest that MMS4 functions after the single end invasion step of...

  18. Microbial transformations of ferulic acid by Saccharomyces cerevisiae and Pseudomonas fluorescens.

    OpenAIRE

    Huang, Z.; Dostal, L; Rosazza, J P

    1993-01-01

    Saccharomyces cerevisiae (dry baker's yeast) and Pseudomonas fluorescens were used to convert trans-ferulic acid into 4-hydroxy-3-methoxystyrene in 96 and 89% yields, respectively. The metabolites were isolated by solid-phase extraction and analyzed by thin-layer chromatography and high-performance liquid chromatography. The identities of the metabolites were determined by 1H- and 13C-nuclear magnetic resonance spectroscopy and by mass spectrometry. The mechanism of the decarboxylation of fer...

  19. Effects of unsaturated fatty acid deprivation on neutral lipid synthesis in Saccharomyces cerevisiae.

    OpenAIRE

    Buttke, T M; Pyle, A L

    1982-01-01

    The effects of unsaturated fatty acid deprivation on lipid synthesis in Saccharomyces cerevisiae strain GL7 were determined by following the incorporation of [14C]acetate. Compared to yeast cells grown with oleic acid, unsaturated fatty acid-deprived cells contained 200 times as much 14C label in squalene, with correspondingly less label in 2,3-oxidosqualene and 2,3;22,23-dioxidosqualene. Cells deprived of either methionine or cholesterol did not accumulate squalene, demonstrating that the ef...

  20. NDT80, a meiosis-specific gene required for exit from pachytene in Saccharomyces cerevisiae.

    OpenAIRE

    Xu, L.; Ajimura, M.; Padmore, R; KLEIN, C; Kleckner, N.

    1995-01-01

    We describe the identification of a new meiosis-specific gene of Saccharomyces cerevisiae, NDT80. The ndt80 null and point mutants arrest at the pachytene stage of meiosis, with homologs connected by full-length synaptonemal complexes and spindle pole bodies duplicated but unseparated. Meiotic recombination in an ndt80 delta mutant is relatively normal, although commitment to heteroallelic recombination is elevated two- to threefold and crossing over is decreased twofold compared with those o...

  1. The Sum1/Ndt80 Transcriptional Switch and Commitment to Meiosis in Saccharomyces cerevisiae

    OpenAIRE

    Winter, Edward

    2012-01-01

    Summary: Cells encounter numerous signals during the development of an organism that induce division, differentiation, and apoptosis. These signals need to be present for defined intervals in order to induce stable changes in the cellular phenotype. The point after which an inducing signal is no longer needed for completion of a differentiation program can be termed the “commitment point.” Meiotic development in the yeast Saccharomyces cerevisiae (sporulation) provides a model system to study...

  2. Defect in two pleiotropic drug resistance transporters causes extensive changes in physiology of Saccharomyces cerevisiae populations.

    Czech Academy of Sciences Publication Activity Database

    Hlavá?ek, Otakar; Ku?erová, Helena; Palková, Zdena; Váchová, Libuše

    Helsinki : Springer, 2007, s. 98-98. [European Federation of Biotechnology Conference /3./. Helsinki (FI), 13.06.2007-16.06.2007] R&D Projects: GA ?R GP204/05/P175; GA ?R GA525/05/0297; GA MŠk(CZ) LC531 Institutional research plan: CEZ:AV0Z50200510 Keywords : saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  3. Mutational inactivation of the Saccharomyces cerevisiae RAD4 gene in Escherichia coli.

    OpenAIRE

    Fleer, R; Siede, W; Friedberg, E.C.

    1987-01-01

    The RAD4 gene of Saccharomyces cerevisiae is required for the incision of damaged DNA during nucleotide excision repair. When plasmids containing the wild-type gene were transformed into various Escherichia coli strains, transformation frequencies were drastically reduced. Most plasmids recovered from transformants showed deletions or rearrangements. A minority of plasmids recovered from E. coli HB101 showed no evidence of deletion or rearrangement, but when they were transformed into S. cere...

  4. Protective effect of acetic acid against ethanol-induced cell death in "Saccharomyces cerevisiae"

    OpenAIRE

    Afonso, Andreia Fernandes

    2011-01-01

    O etanol é um produto final bem conhecido da fermentação alcoólica realizada por Saccharomyces cerevisiae. Em altas concentrações, é responsável pela redução de viabilidade celular e inibição da fermentação. Além disso, durante a fermentação alguns ácidos fracos, como os ácidos acético, butírico e pirúvico, produzidos pelo metabolismo da levedura, podem acumular-se no meio de crescimento e aumentar a toxicidade do etanol, o que resulta numa maior inibição de crescimento e fermentação (Gibson,...

  5. Topological basis of signal integration in the transcriptional-regulatory network of the yeast, Saccharomyces cerevisiae

    OpenAIRE

    Chennubhotla Chakra; Wu Chuang; Farkas Illés J; Bahar Ivet; Oltvai Zoltán N

    2006-01-01

    Abstract Background Signal recognition and information processing is a fundamental cellular function, which in part involves comprehensive transcriptional regulatory (TR) mechanisms carried out in response to complex environmental signals in the context of the cell's own internal state. However, the network topological basis of developing such integrated responses remains poorly understood. Results By studying the TR network of the yeast Saccharomyces cerevisiae we show that an intermediate l...

  6. Regulation of allantoate transport in wild-type and mutant strains of Saccharomyces cerevisiae.

    OpenAIRE

    Chisholm, V T; Lea, H Z; Rai, R; Cooper, T G

    1987-01-01

    Accumulation of intracellular allantoin and allantoate is mediated by two distinct active transport systems in Saccharomyces cerevisiae. Allantoin transport (DAL4 gene) is inducible, while allantoate uptake is constitutive (it occurs at full levels in the absence of any allantoate-related compounds from the culture medium). Both systems appear to be sensitive to nitrogen catabolite repression, feedback inhibition, and trans-inhibition. Mutants (dal5) that lack allantoate transport have been i...

  7. Genomic Approach to Identification of Mutations Affecting Caspofungin Susceptibility in Saccharomyces cerevisiae

    OpenAIRE

    Markovich, Sarit; Yekutiel, Aya; Shalit, Itamar; Shadkchan, Yona; Osherov, Nir

    2004-01-01

    The antifungal agent caspofungin (CAS) specifically interferes with glucan synthesis and cell wall formation. To further study the cellular processes affected by CAS, we analyzed a Saccharomyces cerevisiae mutant collection (4,787 individual knockout mutations) to identify new genes affecting susceptibility to the drug. This collection was screened for increased CAS sensitivity (CAS-IS) or increased CAS resistance (CAS-IR). MICs were determined by the broth microdilution method. Disruption of...

  8. Scheffersomyces stipitis: a comparative systems biology study with the Crabtree positive yeast Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Papini, Marta; Nookaew, Intawat; Uhlén, Mathias; Nielsen, Jens

    2012-01-01

    Background: Scheffersomyces stipitis is a Crabtree negative yeast, commonly known for its capacity to ferment pentose sugars. Differently from Crabtree positive yeasts such as Saccharomyces cerevisiae, the onset of fermentation in S. stipitis is not dependent on the sugar concentration, but is regulated by a decrease in oxygen levels. Even though S. stipitis has been extensively studied due to its potential application in pentoses fermentation, a limited amount of information is available about ...

  9. Nonlinear differential equation model for quantification of transcriptional regulation applied to microarray data of Saccharomyces cerevisiae.

    Czech Academy of Sciences Publication Activity Database

    Vu, Thi Tra; Vohradský, Ji?í

    2007-01-01

    Ro?. 35, ?. 1 (2007), s. 279-287. ISSN 0305-1048 R&D Projects: GA ?R GA310/03/0293; GA ?R GA310/04/0804 Grant ostatní: XE(XE) LSHM-CT-2004-005224 Institutional research plan: CEZ:AV0Z50200510 Source of funding: O - opera?né programy Keywords : saccharomyces cerevisiae * gene expression * tra nscriptional regulators Subject RIV: EE - Microbiology, Virology Impact factor: 6.954, year: 2007

  10. Functional Oligomerization of the Saccharomyces cerevisiae Isoprenylcysteine Carboxyl Methyltransferase, Ste14p

    OpenAIRE

    Griggs, Amy M.; Hahne, Kalub; Hrycyna, Christine A

    2010-01-01

    The isoprenylcysteine carboxyl methyltransferase (Icmt) from Saccharomyces cerevisiae, also designated Ste14p, is a 26-kDa integral membrane protein that contains six transmembrane spanning segments. This protein is localized to the endoplasmic reticulum membrane where it performs the methylation step of the CAAX post-translational processing pathway. Sequence analysis reveals a putative GXXXG dimerization motif located in transmembrane 1 of Ste14p, but it is not known whether Ste14p forms or...

  11. Transcriptional activation upon pheromone stimulation mediated by a small domain of Saccharomyces cerevisiae Ste12p.

    OpenAIRE

    Pi, H.; Chien, C T; Fields, S

    1997-01-01

    In the yeast Saccharomyces cerevisiae, Ste12p induces transcription of pheromone-responsive genes by binding to a DNA sequence designated the pheromone response element. We generated a series of hybrid proteins of Ste12p with the DNA-binding and activation domains of the transcriptional activator Gal4p to define a pheromone induction domain of Ste12p sufficient to mediate pheromone-induced transcription by these hybrid proteins. A minimal pheromone induction domain, delineated as residues 301...

  12. ENHANCEMENT OF SACCHAROMYCES CEREVISIAE GLUTATHIONE AND MICRONUTRIENTS CONTENT FOR NUTRACEUTICAL APPLICATIONS.

    OpenAIRE

    MUSATTI, ALIDA

    2012-01-01

    This Ph.D. research concerns nutritional and microbiological aspects, and the final aim of this project is the development of innovative food supplements formulations containing Saccharomyces cerevisiae, enriched, by biotechnological processes, with micronutrients and antioxidant molecules. This idea was supported by the fact that even if in the developed world a clinical deficiency of micronutrients is uncommon, a suboptimal intake of certain micronutrients has been linked with an increa...

  13. Role of inositol-containing sphingolipids in Saccharomyces cerevisiae during inositol starvation.

    OpenAIRE

    Hanson, B A

    1984-01-01

    The in vitro lipid requirements of UDP-N-acetylglucosamine-dolichol phosphate N-acetylglucosamine-1-phosphotransferase for the inositol-containing sphingolipids from Saccharomyces cerevisiae were characterized in terms of concentration and specificity. The effects of combinations of lipids, especially phosphatidylinositol and the inositol-containing sphingolipids, were also tested on the transferase. Phosphatidylinositol and phosphatidylglycerol stimulated the enzyme 3.3- and 2.8-fold, respec...

  14. Metabolism of myo-inositol during sporulation of myo-inositol-requiring Saccharomyces cerevisiae.

    OpenAIRE

    Schroeder, R.; Breitenbach, M.

    1981-01-01

    We investigated the sporulation properties of a series of diploid Saccharomyces cerevisiae strains homozygous for inositol auxotrophic markers. The strains required different amounts of inositol for the completion of sporulation. Shift experiments revealed two phases of inositol requirement during sporulation which coincided with the two phases of lipid synthesis found by earlier workers. Phase I was at the beginning and during premeiotic deoxyribonucleic acid synthesis; phase II immediately ...

  15. A Mapping Method for SACCHAROMYCES CEREVISIAE Using rad52-Induced Chromosome Loss

    OpenAIRE

    Schild, David; Mortimer, Robert K.

    1985-01-01

    Saccharomyces cerevisiae diploids homozygous for the rad52-1 mutation have previously been shown to lose chromosomes mitotically. Spontaneous events and events following low levels of X-ray or methyl methanesulfonate treatment result in monosomic diploids, whereas higher levels of treatment result in near haploidization. This rad52-1-dependent chromosome loss has been used to develop a new mapping method which can be used to assign a previously unmapped gene to a chromosome. Chromosome loss ...

  16. Genome structure of a Saccharomyces cerevisiae strain widely used in bioethanol production

    OpenAIRE

    Argueso, Juan Lucas; Carazzolle, Marcelo F.; Mieczkowski, Piotr A; Duarte, Fabiana M.; Netto, Osmar V.C.; Missawa, Silvia K.; Galzerani, Felipe; Gustavo G.L. Costa; Vidal, Ramon O.; Noronha, Melline F; Dominska, Margaret; Andrietta, Maria G.S.; Andrietta, Sílvio R.; Cunha, Anderson F; Gomes, Luiz H.

    2009-01-01

    Bioethanol is a biofuel produced mainly from the fermentation of carbohydrates derived from agricultural feedstocks by the yeast Saccharomyces cerevisiae. One of the most widely adopted strains is PE-2, a heterothallic diploid naturally adapted to the sugar cane fermentation process used in Brazil. Here we report the molecular genetic analysis of a PE-2 derived diploid (JAY270), and the complete genome sequence of a haploid derivative (JAY291). The JAY270 genome is highly heterozygous (?2 SNP...

  17. Cloning and characterization of a gene which determines osmotic stability in Saccharomyces cerevisiae.

    OpenAIRE

    Stateva, L I; Oliver, S. G.; Trueman, L J; Venkov, P V

    1991-01-01

    The srb1-1 mutation of Saccharomyces cerevisiae is an ochre allele which renders the yeast dependent on an osmotic stabilizer for growth and gives the cells the ability to lyse on transfer to hypotonic conditions. A DNA fragment which complements both of these phenotypic effects has been cloned. This clone contains a functional gene which is transcribed into a 2.3-kb polyadenylated mRNA molecule. Transformation of yeast strains carrying defined suppressible alleles demonstrated that the clone...

  18. Metabolome Studies of Stress Responses in Saccharomyces Cerevisiae : - implementation of sampling and analytical protocols

    OpenAIRE

    Haug, Anne Marte

    2011-01-01

    As a part of cancer research and therapy, it is important to study metabolic responses caused by DNA damaging agents. Whereas earlier studies have focused on changes at protein levels caused by DNA damaging agents, this project focuses on establishment of sampling and cultivation protocols for metabolome analysis, using Saccharomyces cerevisiae as a model organism growing in exponential phase. Sampling and cultivations protocols were optimized before cultures were stressed by DNA damaging age...

  19. Hog1 Controls Global Reallocation of RNA Pol II upon Osmotic Shock in Saccharomyces cerevisiae

    OpenAIRE

    Cook, Kristen; O'Shea, Erin K

    2012-01-01

    When challenged with osmotic shock, Saccharomyces cerevisiae induces hundreds of genes, despite a concurrent reduction in overall transcriptional capacity. The stress-responsive MAP kinase Hog1 activates expression of specific genes through interactions with chromatin remodeling enzymes, transcription factors, and RNA polymerase II. However, it is not clear whether Hog1 is involved more globally in modulating the cell’s transcriptional program during stress, in addition to activating specific...

  20. Anaerobicity Prepares Saccharomyces cerevisiae Cells for Faster Adaptation to Osmotic Shock†

    OpenAIRE

    Krantz, Marcus; Nordlander, Bodil; Valadi, Hadi; Johansson, Mikael; Gustafsson, Lena; Hohmann, Stefan

    2004-01-01

    Yeast cells adapt to hyperosmotic shock by accumulating glycerol and altering expression of hundreds of genes. This transcriptional response of Saccharomyces cerevisiae to osmotic shock encompasses genes whose products are implicated in protection from oxidative damage. We addressed the question of whether osmotic shock caused oxidative stress. Osmotic shock did not result in the generation of detectable levels of reactive oxygen species (ROS). To preclude any generation of ROS, osmotic shock...

  1. Ultrasonic Measurements and its Evaluation for the Monitoring of Saccharomyces cerevisiae Cultivation

    OpenAIRE

    Bernd Hitzmann; Young-Lok Cha

    2004-01-01

    The monitoring and supervision of batch Saccharomyces cerevisiae cultivations are presented by ultrasonic velocity measurements. The measurements are performed in a by-pass to reduce the influence of bubbles. Using these signals the typical phases of such cultivations can be identified. Applying a multi-linear regression model the ultrasonic velocity can be estimated by the biomass, the glucose and the ethanol concentration with a mean estimation error of 1.6 m/s. The multi-linear regression ...

  2. Genetic diversity and molecular characterization of Saccharomyces cerevisiae strains from winemaking environments

    OpenAIRE

    Schuller, Dorit

    2004-01-01

    O presente trabalho teve como principal objectivo a avaliação da diversidade genética de estirpes fermentativas de Saccharomyces cerevisiae na Região dos Vinhos Verdes no sentido de estabelecer uma colecção de leveduras, que representa a biodiversidade da região, como recurso para futuros programas de selecção e melhoramento de estirpes enológicas. A validação de métodos moleculares para genotipagem é um pré-requisito essencial para estudos biogeográficos. Neste sentido, foi realizada a an...

  3. Ethanol fermentation of molasses by Saccharomyces cerevisiae cells immobilized onto sugar beet pulp

    OpenAIRE

    Vu?urovi? Vesna M.; Razmovski Radojka N.

    2012-01-01

    Natural adhesion of Saccharomyces cerevisiae onto sugar beet pulp (SBP) is a very simple and cheap immobilization method for retaining high cells density in the ethanol fermentation system. In the present study, yeast cells were immobilized by adhesion onto SBP suspended in the synthetic culture media under different conditions such as: glucose concentration (100, 120 and 150 g/l), inoculum concentration (5, 10 and 15 g/l dry mass) and temperature (25, 30, 35 and 40°C). In order to esti...

  4. Reconstruction of the biosynthetic pathway for the core fungal polyketide scaffold rubrofusarin in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Rugbjerg, Peter; Naesby, Michael; Mortensen, Uffe Hasbro; Frandsen, Rasmus John Normand

    2013-01-01

    ABSTRACT: BACKGROUND: Fungal polyketides include commercially important pharmaceuticals and food additives, e.g. the cholesterol-lowering statins and the red and orange monascus pigments. Presently, production relies on isolation of the compounds from the natural producers, and systems for heterologous production in easily fermentable and genetically engineerable organisms, such as Saccharomyces cerevisiae and Escherichia coli are desirable. Rubrofusarin is an orange polyketide pigment that is a...

  5. Effects of furfural on the respiratory metabolism of Saccharomyces cerevisiae in glucose-limited chemostats,

    OpenAIRE

    Sarvari Horvath, I; Franzén, C J; Taherzadeh, M.J.; Niklasson, C; Lidén, Gunnar

    2003-01-01

    Effects of furfural on the aerobic metabolism of the yeast Saccharomyces cerevisiae were studied by performing chemostat experiments, and the kinetics of furfural conversion was analyzed by performing dynamic experiments. Furfural, an important inhibitor present in lignocellulosic hydrolysates, was shown to have an inhibitory effect on yeast cells growing respiratively which was much greater than the inhibitory effect previously observed for anaerobically growing yeast cells. The residual fur...

  6. Saccharomyces cerevisiae exhibits a yAP-1-mediated adaptive response to malondialdehyde.

    OpenAIRE

    Turton, H E; Dawes, I. W.; Grant, C. M.

    1997-01-01

    Malondialdehyde (MDA) is a highly reactive aldehyde generally formed as a consequence of lipid peroxidation. MDA has been inferred to have mutagenic and cytotoxic roles and possibly to be a participant in the onset of atherosclerosis. Wild-type Saccharomyces cerevisiae acquires resistance to a lethal dose (5 mM) of MDA following prior exposure to a nonlethal concentration (1 mM). This response was completely inhibited by cycloheximide (50 microg ml(-1)), indicating a requirement for protein s...

  7. Metabolic link between phosphatidylethanolamine and triacylglycerol metabolism in the yeast Saccharomyces cerevisiae

    OpenAIRE

    Horvath, Susanne E.; Wagner, Andrea; Steyrer, Ernst; Daum, Günther

    2011-01-01

    In the yeast Saccharomyces cerevisiae triacylglycerols (TAG) are synthesized by the acyl-CoA dependent acyltransferases Dga1p, Are1p, Are2p and the acyl-CoA independent phospholipid:diacylglycerol acyltransferase (PDAT) Lro1p which uses phosphatidylethanolamine (PE) as a preferred acyl donor. In the present study we investigated a possible link between TAG and PE metabolism by analyzing the contribution of the four different PE biosynthetic pathways to TAG formation, namely de novo PE synthes...

  8. Synthesis of Polyhydroxyalkanoate in the Peroxisome of Saccharomyces cerevisiae by Using Intermediates of Fatty Acid ?-Oxidation

    OpenAIRE

    Poirier, Yves; Erard, Nadine; Petétot, Jean MacDonald-Comber

    2001-01-01

    Medium-chain-length polyhydroxyalkanoates (PHAs) are polyesters having properties of biodegradable thermoplastics and elastomers that are naturally produced by a variety of pseudomonads. Saccharomyces cerevisiae was transformed with the Pseudomonas aeruginosa PHAC1 synthase modified for peroxisome targeting by the addition of the carboxyl 34 amino acids from the Brassica napus isocitrate lyase. The PHAC1 gene was put under the control of the promoter of the catalase A gene. PHA synthase expre...

  9. Differential importance of trehalose in stress resistance in fermenting and nonfermenting Saccharomyces cerevisiae cells.

    OpenAIRE

    Dijck, P., van; Colavizza, D; Smet, P; Thevelein, J M

    1995-01-01

    The trehalose content in laboratory and industrial baker's yeast is widely believed to be a major determinant of stress resistance. Fresh and dried baker's yeast is cultured to obtain a trehalose content of more than 10% of the dry weight. Initiation of fermentation, e.g., during dough preparation, is associated with a rapid loss of stress resistance and a rapid mobilization of trehalose. Using specific Saccharomyces cerevisiae mutants affected in trehalose metabolism, we confirm the correlat...

  10. Internal Trehalose Protects Endocytosis from Inhibition by Ethanol in Saccharomyces cerevisiae

    OpenAIRE

    Lucero, P; Peñalver, E; Moreno, E.; Lagunas, R.

    2000-01-01

    Endocytosis in Saccharomyces cerevisiae is inhibited by concentrations of ethanol of 2 to 6% (vol/vol), which are lower than concentrations commonly present in its natural habitats. In spite of this inhibition, endocytosis takes place under enological conditions when high concentrations of ethanol are present. Therefore, it seems that yeast has developed some means to circumvent the inhibition. In this work we have investigated this possibility. We identified two stress conditions under which...

  11. Exploiting Spore-Autonomous Fluorescent Protein Expression to Quantify Meiotic Chromosome Behaviors in Saccharomyces cerevisiae

    OpenAIRE

    Thacker, Drew; Lam, Isabel; Knop, Michael; Keeney, Scott

    2011-01-01

    The budding yeast Saccharomyces cerevisiae has proven to be a rich source of information about the mechanisms and regulation of homologous recombination during meiosis. A common technique for studying this process involves microdissecting the four products (ascospores) of a single meiosis and analyzing the configuration of genetic markers in the spores that are viable. Although this type of analysis is powerful, it can be laborious and time-consuming to characterize the large numbers of meios...

  12. Analyse Systémique de la Modulation de la bascule respiro-fermentaire chez Saccharomyces cerevisiae

    OpenAIRE

    Feria Gervasio, David

    2008-01-01

    L’objective de notre travail est d’étudier la transition métabolique respiro-fermentaire chez Saccharomyces cerevisiae, plus spécifiquement d’évaluer l’importance du transport du carbone issu du métabolisme de l’acétyl-coenzymeA vers la mitochondrie. Pour ce faire, une approche originale du génie microbiologique a été mise en place basée sur l’utilisation de chémostat sur substrats mixtes. Cela consiste à introduire au cours d’un chémostat oxydatif sous limitation glucose une pert...

  13. Continuous ethanol fermentation of lactose by a recombinant flocculating saccharomyces cerevisiae strain

    OpenAIRE

    Domingues, Luc??lia; Dantas, Maria M.; Lima, Nelson; Teixeira, J. A.

    1998-01-01

    Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cerevisiae, expressing the LAC4 (coding for b-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to t...

  14. Genome-wide analysis of mRNA translation profiles in Saccharomyces cerevisiae

    OpenAIRE

    Arava, Yoav; Wang, Yulei; Storey, John D; Liu, Chih Long; Brown, Patrick O; Herschlag, Daniel

    2003-01-01

    We have analyzed the translational status of each mRNA in rapidly growing Saccharomyces cerevisiae. mRNAs were separated by velocity sedimentation on a sucrose gradient, and 14 fractions across the gradient were analyzed by quantitative microarray analysis, providing a profile of ribosome association with mRNAs for thousands of genes. For most genes, the majority of mRNA molecules were associated with ribosomes and presumably engaged in translation. This systematic approach enabled us to reco...

  15. Characterization of surface-exposed reactive cysteine residues in Saccharomyces cerevisiae

    OpenAIRE

    Marino, Stefano M.; Li, Yehua; Fomenko, Dmitri E; Agisheva, Natalia; L.Cerny, Ronald; GLADYSHEV, Vadim N.

    2010-01-01

    Numerous cellular processes are subject to redox regulation, and thiol-dependent redox control, acting through reactive cysteine (Cys) residues, is among the major mechanisms of redox regulation. However, information on the sets of proteins that provide thiol-based redox regulation or are affected by it is limited. Here, we describe proteomic approaches to characterize proteins that contain reactive thiols and methods to identify redox Cys in these proteins. Using Saccharomyces cerevisiae as ...

  16. CrEdit: CRISPR mediated multi-loci gene integration in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Ronda, Carlotta; Maury, Jerome; Jakociunas, Tadas; Jacobsen, Simo Abdessamad Baallal; Germann, Susanne Manuela; Harrison, Scott James; Borodina, Irina; Keasling, Jay D.; Jensen, Michael Krogh; Nielsen, Alex Toftgaard

    2015-01-01

    Background: One of the bottlenecks in production of biochemicals and pharmaceuticals in Saccharomyces cerevisiae is stable and homogeneous expression of pathway genes. Integration of genes into the genome of the production organism is often a preferred option when compared to expression from episomal vectors. Existing approaches for achieving stable simultaneous genome integrations of multiple DNA fragments often result in relatively low integration efficiencies and furthermore rely on the use o...

  17. CRISPR–Cas system enables fast and simple genome editing of industrial Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    Stovicek, Vratislav; Borodina, Irina; Förster, Jochen

    2015-01-01

    There is a demand to develop 3rd generation biorefineries that integrate energy production with the production of higher value chemicals from renewable feedstocks. Here, robust and stress-tolerant industrial strains of Saccharomyces cerevisiae will be suitable production organisms. However, their genetic manipulation is challenging, as they are usually diploid or polyploid. Therefore, there is a need to develop more efficient genetic engineering tools. We applied a CRISPR–Cas9 system for genome ...

  18. Function and Regulation in MAPK Signaling Pathways: Lessons Learned from the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Chen, Raymond E; Thorner, Jeremy

    2007-01-01

    Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) elicit many of the responses that are evoked in cells by changes in certain environmental conditions and upon exposure to a variety of hormonal and other stimuli. These pathways were first elucidated in the unicellular eukaryote Saccharomyces cerevisiae (budding yeast). Studies of MAPK pathways in this organism continue to be especially informative in revealing the molecular mechanisms by which MAPK cascades ...

  19. Alternative Splicing of PTC7 in Saccharomyces cerevisiae Determines Protein Localization

    OpenAIRE

    Juneau, Kara; Nislow, Corey; Davis, Ronald W.

    2009-01-01

    It is well established that higher eukaryotes use alternative splicing to increase proteome complexity. In contrast, Saccharomyces cerevisiae, a single-cell eukaryote, conducts predominantly regulated splicing through retention of nonfunctional introns. In this article we describe our discovery of a functional intron in the PTC7 (YHR076W) gene that can be alternatively spliced to create two mRNAs that code for distinct proteins. These two proteins localize to different cellular compartments a...

  20. An improved method for whole protein extraction from yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Zhang, Tingting; Lei, Jie; Yang, Hanjiang; Xu, Kun; Wang, Rui; Zhang, Zhiying

    2011-11-01

    A new method for protein extraction from yeast Saccharomyces cerevisiae cells is described. This method involves the use of LiAc and NaOH to enhance the permeability of yeast cell wall prior to protein extraction with SDS-PAGE sample buffer. It was safe and efficient compared to other methods reported so far in the literature. The proteins extracted with this new method retained their immunoreactive properties and are suitable for most applications in molecular biology studies. PMID:21972073

  1. Electrochemical Probing of in Vivo 5-Hydroxymethyl Furfural Reduction in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Almeida, J.R.M.; Heiskanen, Arto; Gorwa-Grauslund, M.F.; Hahn-Hagerdal, B.; Emnéus, Jenny

    2009-01-01

    In this work, mediated amperometry was used to evaluate whether differences in intracellular nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) level could be observed between a genetically modified Saccharomyces cerevisiae strain, engineered for NADPH dependent 5-hydroxymethyl-2-furaldehyde (HMF) reduction, and its control strain. Cells overexpressing the alcohol dehydrogenase 6 gene (ADH6 strain) and cells carrying the corresponding control plasmid (control strain) were each immobilized o...

  2. Fermentation performance of engineered and evolved xylose-fermenting Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    Sonderegger, M.; Jeppsson, M.; Larsson, C.; Gorwa-Grauslund, M.F.; Boles, E.; Olsson, Lisbeth; Spencer-Martins, I.; Hahn-Hagerdal, B.; Sauer, U.

    2004-01-01

    Lignocellulose hydrolysate is an abundant substrate for bioethanol production. The ideal microorganism for such a fermentation process should combine rapid and efficient conversion of the available carbon sources to ethanol with high tolerance to ethanol and to inhibitory components in the hydrolysate. A particular biological problem are the pentoses, which are not naturally metabolized by the main industrial ethanol producer Saccharomyces cerevisiae. Several recombinant, mutated, and evolved xy...

  3. Enhanced xylose fermentation and ethanol production by engineered Saccharomyces cerevisiae strain

    OpenAIRE

    Vilela, Leonardo de Figueiredo; de Araujo, Verônica Parente Gomes; Paredes, Raquel de Sousa; Bon, Elba Pinto da Silva; Torres, Fernando Araripe Gonçalves; Neves, Bianca Cruz; Eleutherio, Elis Cristina Araújo

    2015-01-01

    We have recently demonstrated that heterologous expression of a bacterial xylose isomerase gene (xylA) of Burkholderia cenocepacia enabled a laboratorial Saccharomyces cerevisiae strain to ferment xylose anaerobically, without xylitol accumulation. However, the recombinant yeast fermented xylose slowly. In this study, an evolutionary engineering strategy was applied to improve xylose fermentation by the xylA-expressing yeast strain, which involved sequential batch cultivation on xylose. The r...

  4. Ethanol Production from Sago Waste Using Saccharomyces cerevisiae Vits-M1

    OpenAIRE

    D. Subashini; J. Ejilane; A. Radha; M.A. Jayasri and K. Suthindhiran

    2011-01-01

    The present study deals with the biotechnological production of ethanol from sago waste materials. As petroleum has become depleted, renewable energy production has started to gain attention all over the world, including the production of ethanol from sago wastes. In our research we have standardized the production of ethanol from sago wastes using Saccharomyces cerevisiae strain isolated from molasses. The production of ethanol was carried out by means of simultaneous saccharification with a...

  5. Impact of Photocatalysis on Fungal Cells: Depiction of Cellular and Molecular Effects on Saccharomyces cerevisiae

    OpenAIRE

    Thabet, Sana; Simonet, France; Lemaire, Marc; Guillard, Chantal; Cotton, Pascale

    2014-01-01

    We have investigated the antimicrobial effects of photocatalysis on the yeast model Saccharomyces cerevisiae. To accurately study the antimicrobial mechanisms of the photocatalytic process, we focused our investigations on two questions: the entry of the nanoparticles in treated cells and the fate of the intracellular environment. Transmission electronic microscopy did not reveal any entry of nanoparticles within the cells, even for long exposure times, despite degradation of the cell wall sp...

  6. Ure2p Function Is Enhanced by Its Prion Domain in Saccharomyces cerevisiae

    OpenAIRE

    Shewmaker, Frank; Mull, Lori; Nakayashiki, Toru; Masison, Daniel C.; Wickner, Reed B.

    2007-01-01

    The Ure2 protein of Saccharomyces cerevisiae can become a prion (infectious protein). At very low frequencies Ure2p forms an insoluble, infectious amyloid known as [URE3], which is efficiently transmitted to progeny cells or mating partners that consequently lose the normal Ure2p nitrogen regulatory function. The [URE3] prion causes yeast cells to grow slowly, has never been identified in the wild, and confers no obvious phenotypic advantage. An N-terminal asparagine-rich domain determines Ur...

  7. Effect of ARS1 mutations on chromosome stability in Saccharomyces cerevisiae.

    OpenAIRE

    Srienc, F; Bailey, J. E.; Campbell, J. L.

    1985-01-01

    We have used a set of deletion mutations in the ARS1 element of Saccharomyces cerevisiae to measure their effect on chromosome stability. This work establishes the previously proposed existence of three domains in ARS1. Domain C, which we have previously inferred, but not proved, to be a part of ARS1, is now established. In addition, we show that increasingly large deletions of the domain have increasingly large effects, which was not realized before. Furthermore, we have provided the first p...

  8. Susceptibility of Saccharomyces cerevisiae and lactic acid bacteria from the alcohol industry to several antimicrobial compounds

    OpenAIRE

    Oliva-Neto Pedro de; Yokoya Fumio

    2001-01-01

    The antimicrobial effect of several products including commercial formulations currently used in sugar and alcohol factories was determined by adapted MIC (Minimal Inhibitory Concentration) test on Saccharomyces cerevisiae and on natural contaminants Lactobacillus fermentum and Leuconostoc mesenteroides. The MIC test by macrodilution broth method was adapted by formulating of the culture medium with cane juice closely simulating industrial alcoholic fermentation must. Acid penicillin V (MIC 0...

  9. Transcriptional Regulation of the Two Sterol Esterification Genes in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Jensen-Pergakes, Kristen; Guo, Zhongmin; Giattina, Mara; Sturley, Stephen L; Bard, Martin

    2001-01-01

    Saccharomyces cerevisiae transcribes two genes, ARE1 and ARE2, that contribute disproportionately to the esterification of sterols. Are2p is the major enzyme isoform in a wild-type cell growing aerobically. This likely results from a combination of differential transcription initiation and transcript stability. By using ARE1 and ARE2 promoter fusions to lacZ reporters, we demonstrated that transcriptional initiation from the ARE1 promoter is significantly reduced compared to that from the ARE...

  10. Allantoin transport in Saccharomyces cerevisiae is regulated by two induction systems.

    OpenAIRE

    Cooper, T G; Chisholm, V T; Cho, H. J.; Yoo, H S

    1987-01-01

    We show that the allantoin transport system of Saccharomyces cerevisiae responds to two induction systems, one mediated by allophanate or its analog oxalurate and the other mediated by allantoin or its analog hydantoin acetate. The effects of the two inducers were additive in strain M85. Like other allantoin pathway genes, oxalurate-mediated induction of allantoin transport required a functional DAL81 gene product. Hydantoin acetate-mediated induction of the system, on the other hand, occurre...

  11. Isolation and characterization of mutants that produce the allantoin-degrading enzymes constitutively in Saccharomyces cerevisiae.

    OpenAIRE

    Chisholm, G; Cooper, T G

    1982-01-01

    Degradation of allantoin, allantoate, or urea by Saccharomyces cerevisiae requires the participation of four enzymes and four transport systems. Production of the four enzymes and one of the active transport systems is inducible; allophanate, the last intermediate of the pathway, functions as the inducer. The involvement of allophanate in the expression of five distinct genes suggested that they might be regulated by a common element. This suggestion is now supported by the isolation of a new...

  12. Location of the Genes That Control Induction of the Allantoin-Degrading Enzymes in SACCHAROMYCES CEREVISIAE

    OpenAIRE

    Turoscy, Vanessa; Chisholm, George; Cooper, Terrance G.

    1984-01-01

    In an effort to understand the regulation of allantoin degradation in Saccharomyces cerevisiae, we isolated two classes of mutants, each defective in the induction process associated with production of the pathway enzymes. Mutation at one locus (DAL80) results in constitutive expression of the genes involved in allantoin catabolism. Mutation at the second locus (DAL-81) results in the loss of ability to induce these enzymes. This report describes genetic data indicating that the DAL80 and DA...

  13. A metabolic and genomic study of engineered saccharomyces cerevisiae strains for high glycerol production

    OpenAIRE

    Cordier, Hélène; Filipa, Mendes; Isabel, Vasconcelos; François, Jean M

    2007-01-01

    Towards a global objective to producechemical derivatives by microbial processes, this work dealt with a metabolic engineering of theyeast Saccharomyces cerevisiae for glycerol production. To accomplish this goal, overexpression of GPD1was introduced in a tpi1D mutant defective in triose phosphateisomerase. This strategy alleviated the inositol-less phenotype of this mutant, by reducing the levelsof dihydroxyacetone phosphate and glycerol-3-P, two potent inhibitors of myo-inositol synthase...

  14. Adsorption and interfacial electron transfer of Saccharomyces cerevisiae yeast cytochrome c monolayers on Au(111) electrodes

    DEFF Research Database (Denmark)

    Hansen, Allan Glargaard; Boisen, Anja; Nielsen, Jens Ulrik; Wackerbarth, Hainer; Chorkendorff, Ib; Andersen, Jens Enevold Thaulov; Zhang, Jingdong; Ulstrup, Jens

    2003-01-01

    We have studied the adsorption and electron-transfer dynamics of Saccharomyces cerevisiae (yeast) iso-1-cytochrome c adsorbed on Au(111) electrodes in aqueous phosphate buffer media. This cytochrome possesses a thiol group close to the protein surface (Cys102) suitable for linking the protein to gold without drastic protein unfolding. A comprehensive approach, based on linear sweep and differential pulse voltammetry, capacitance measurements, X-ray photoelectron spectroscopy (XPS), in situ scann...

  15. Three regulatory systems control production of glutamine synthetase in Saccharomyces cerevisiae.

    OpenAIRE

    Mitchell, A. P.; Magasanik, B

    1984-01-01

    Production of glutamine synthetase in Saccharomyces cerevisiae is controlled by three regulatory systems. One system responds to glutamine levels and depends on the positively acting GLN3 product. This system mediates derepression of glutamine synthetase in response to pyrimidine limitation as well, but genetic evidence argues that this is an indirect effect of depletion of the glutamine pool. The second system is general amino acid control, which couples derepression of a variety of biosynth...

  16. Cloning and characterization of Saccharomyces cerevisiae genes that confer L-methionine sulfoximine and tabtoxin resistance.

    OpenAIRE

    Marek, E T; Dickson, R. C.

    1987-01-01

    Pseudomonas tabaci produces a toxin, tabtoxin, that causes wildfire disease in tobacco. The primary target of tabtoxin is presumed to be glutamine synthetase. Some effects of tabtoxin in tobacco can be mimicked by methionine sulfoximine (MSO), a compound that is known to inactivate glutamine synthetase. To understand how organisms can be made resistant to tabtoxin and MSO, we used Saccharomyces cerevisiae. We demonstrate that yeast strains carrying the glutamine synthetase gene, GLN1, on a mu...

  17. Regulation of glutamine-repressible gene products by the GLN3 function in Saccharomyces cerevisiae.

    OpenAIRE

    Mitchell, A. P.; Magasanik, B

    1984-01-01

    Mutants of the yeast Saccharomyces cerevisiae have been isolated which fail to derepress glutamine synthetase upon glutamine limitation. The mutations define a single nuclear gene, GLN3, which is located on chromosome 5 near HOM3 and HIS1 and is unlinked to the structural gene for glutamine synthetase, GLN1. The three gln3 mutations are recessive, and one is amber suppressible, indicating that the GLN3 product is a positive regulator of glutamine synthetase expression. Four polypeptides, in a...

  18. Glutamine synthesis is a regulatory signal controlling glucose catabolism in Saccharomyces cerevisiae.

    OpenAIRE

    Flores-Samaniego, B; H. Olivera; González, A.

    1993-01-01

    The effect of glutamine biosynthesis and degradation on glucose catabolism in Saccharomyces cerevisiae was studied. A wild-type strain and mutants altered in glutamine biosynthesis and degradation were analyzed. Cells having low levels of glutamine synthetase activity showed high ATP/ADP ratios and a diminished rate of glucose metabolism. It is proposed that glutamine biosynthesis plays a role in the regulation of glucose catabolism.

  19. Biogenesis of the Saccharomyces cerevisiae Pheromone a-Factor, from Yeast Mating to Human Disease

    OpenAIRE

    Michaelis, Susan; Barrowman, Jemima

    2012-01-01

    Summary: The mating pheromone a-factor secreted by Saccharomyces cerevisiae is a farnesylated and carboxylmethylated peptide and is unusually hydrophobic compared to other extracellular signaling molecules. Mature a-factor is derived from a precursor with a C-terminal CAAX motif that directs a series of posttranslational reactions, including prenylation, endoproteolysis, and carboxylmethylation. Historically, a-factor has served as a valuable model for the discovery and functional analysis of...

  20. Members of the Hsp70 family of proteins in the cell wall of Saccharomyces cerevisiae.

    OpenAIRE

    López-Ribot, J L; Chaffin, W. L.

    1996-01-01

    Western blot (immunoblot) analysis of cell wall and cytosolic extracts obtained from parental and ssa1 and ssa2 single- and double-mutant strains of Saccharomyces cerevisiae showed that the heat shock protein 70 (Hsp70) products of these genes, previously thought to be restricted to the cell interior, are also present in the cell wall. A cell wall location was further confirmed by indirect immunofluorescence with intact cells and biotinylation of extracellular Hsp70. Hsp70s have been implicat...

  1. The Linker Histone Plays a Dual Role during Gametogenesis in Saccharomyces cerevisiae

    OpenAIRE

    Bryant, Jessica M; Govin, Jérôme; Zhang, Liye; Donahue, Greg; Pugh, B. Franklin; Berger, Shelley L.

    2012-01-01

    The differentiation of gametes involves dramatic changes to chromatin, affecting transcription, meiosis, and cell morphology. Sporulation in Saccharomyces cerevisiae shares many chromatin features with spermatogenesis, including a 10-fold compaction of the nucleus. To identify new proteins involved in spore nuclear organization, we purified chromatin from mature spores and discovered a significant enrichment of the linker histone (Hho1). The function of Hho1 has proven to be elusive during ve...

  2. Efficiency of supplementing saccharomyces cerevisiae var. ellipsoideus for improved growth performance and carcass yield in broilers

    OpenAIRE

    M. H. Ayed; F. Ghaoui

    2011-01-01

    The use of dietary additives is becoming a very interesting practise to improve animal health and performance in poultry production. Thepax® is a prebiotic that includes inactivated Saccharomyces cerevisiae Var. ellipsoideus cells and nutrients such as vitamins, enzymes, amino acids and short chain polypeptides. The effects of supplementing diet by Thepax® via potable water on growth and carcass yield were studied in broilers. Two treatments, an active with Thepax® and a control treatment, we...

  3. Phosphorylation of RAS1 and RAS2 proteins in Saccharomyces cerevisiae.

    OpenAIRE

    Cobitz, A R; Yim, E H; Brown, W R; Perou, C. M.; Tamanoi, F

    1989-01-01

    RAS1 and RAS2 proteins of Saccharomyces cerevisiae are guanine nucleotide-binding proteins involved in the regulation of adenylate cyclase. In this paper, we report that these proteins are phosphorylated. The phosphorylation of RAS1 protein is demonstrated by treating with alkaline phosphatase as well as by labeling with [32P]orthophosphate. The phosphorylation occurs exclusively on serine residues and phosphorylated RAS1 protein is predominantly membrane localized. The phosphorylation of RAS...

  4. Switch between Life History Strategies Due to Changes in Glycolytic Enzyme Gene Dosage in Saccharomyces cerevisiae? †

    OpenAIRE

    Wang, Shaoxiao; SPOR, Aymé; Nidelet, Thibault; Montalent, Pierre; DILLMANN, Christine; de Vienne, Dominique; SICARD, Delphine

    2010-01-01

    Adaptation is the process whereby a population or species becomes better fitted to its habitat through modifications of various life history traits which can be positively or negatively correlated. The molecular factors underlying these covariations remain to be elucidated. Using Saccharomyces cerevisiae as a model system, we have investigated the effects on life history traits of varying the dosage of genes involved in the transformation of resources into energy. Changing gene dosage for eac...

  5. System-Level Analysis of Genes and Functions Affecting Survival During Nutrient Starvation in Saccharomyces cerevisiae

    OpenAIRE

    Gresham, David; Boer, Viktor M.; Caudy, Amy; Ziv, Naomi; Brandt, Nathan J.; Storey, John D; Botstein , David

    2011-01-01

    An essential property of all cells is the ability to exit from active cell division and persist in a quiescent state. For single-celled microbes this primarily occurs in response to nutrient deprivation. We studied the genetic requirements for survival of Saccharomyces cerevisiae when starved for either of two nutrients: phosphate or leucine. We measured the survival of nearly all nonessential haploid null yeast mutants in mixed populations using a quantitative sequencing method that estimate...

  6. Encapsulation-Induced Stress Helps Saccharomyces cerevisiae Resist Convertible Lignocellulose Derived Inhibitors

    OpenAIRE

    Westman, Johan O; Ramesh Babu Manikondu; Carl Johan Franzén; Taherzadeh, Mohammad J.

    2012-01-01

    The ability of macroencapsulated Saccharomyces cerevisiae CBS8066 to withstand readily and not readily in situ convertible lignocellulose-derived inhibitors was investigated in anaerobic batch cultivations. It was shown that encapsulation increased the tolerance against readily convertible furan aldehyde inhibitors and to dilute acid spruce hydrolysate, but not to organic acid inhibitors that cannot be metabolized anaerobically. G...

  7. Cellular and mitochondrial respiration of Saccharomyces cerevisiae cells of different age.

    Czech Academy of Sciences Publication Activity Database

    Hlousková, J.; Volejníková, A.; Sigler, Karel; Pichová, Alena

    Smolenice : Springer, 2009, s. 92-92. ISSN 1336-4839. [Annual Conference on Yeasts /37./. Smolenice (SK), 13.05.2009-15.05.2009] R&D Projects: GA ?R GA301/07/0339; GA MŠk 1M0570; GA MŠk ME 938 Institutional research plan: CEZ:AV0Z50200510 Keywords : Saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  8. Zearalenone and its derivatives ?-Zearalenol and ?-Zearalenol decontamination by Saccharomyces cerevisiae strains isolated from bovine forage

    OpenAIRE

    Keller, Luiz; Abrunhosa, Luís; Keller, Kelly; Rosa, Carlos Alberto; Cavaglieri, Lilia; Venâncio, Armando

    2015-01-01

    Zearalenone (ZEA) and its derivatives are mycotoxins with estrogenic effects on mammals. The biotransformation for ZEA in animals involves the formation of two major metabolites, - and -zearalenol (-ZOL and -ZOL), which are subsequently conjugated with glucuronic acid. The capability of Saccharomyces cerevisiae strains isolated from silage to eliminate ZEA and its derivatives -ZOL and -ZOL was investigated as, also, the mechanisms involved. Strains were grown on Yeast Extract-Peptone-Dextrose...

  9. Increasing galactose consumption by Saccharomyces cerevisiae through metabolic engineering of the GAL gene regulatory network

    DEFF Research Database (Denmark)

    Østergaard, Simon; Olsson, Lisbeth; Johnston, M.; Nielsen, Jens

    2000-01-01

    Increasing the flux through central carbon metabolism is difficult because of rigidity in regulatory structures, at both the genetic and the enzymatic levels. Here we describe metabolic engineering of a regulatory network to obtain a balanced increase in the activity of all the enzymes in the pathway, and ultimately, increasing metabolic flux through the pathway of interest, By manipulating the GAL gene regulatory network of Saccharomyces cerevisiae, which is a tightly regulated system, we produ...

  10. Improved Production of a Heterologous Amylase in Saccharomyces cerevisiae by Inverse Metabolic Engineering

    DEFF Research Database (Denmark)

    Liu, Zihe; Liu, Lifang; Osterlund, Tobias; Hou, Jin; Huang, Mingtao; Fagerberg, Linn; Petranovic, Dina; Uhlén, Mathias; Nielsen, Jens

    2014-01-01

    The increasing demand for industrial enzymes and biopharmaceutical proteins relies on robust production hosts with high protein yield and productivity. Being one of the best-studied model organisms and capable of performing posttranslational modifications, the yeast Saccharomyces cerevisiae is widely used as a cell factory for recombinant protein production. However, many recombinant proteins are produced at only 1% (or less) of the theoretical capacity due to the complexity of the secretory pat...

  11. Saccharomyces cerevisiae Transcription Elongation Mutants Are Defective in PUR5 Induction in Response to Nucleotide Depletion

    OpenAIRE

    Shaw, Randal J.; Reines, Daniel

    2000-01-01

    IMP dehydrogenase (IMPDH) is the rate-limiting enzyme in the de novo synthesis of guanine nucleotides. It is a target of therapeutically useful drugs and is implicated in the regulation of cell growth rate. In the yeast Saccharomyces cerevisiae, mutations in components of the RNA polymerase II (Pol II) transcription elongation machinery confer increased sensitivity to a drug that inhibits IMPDH, 6-azauracil (6AU), by a mechanism that is poorly understood. This phenotype is thought to reflect ...

  12. Transfer of a yeast artificial chromosome carrying human DNA from Saccharomyces cerevisiae into mammalian cells.

    OpenAIRE

    Pachnis, V; Pevny, L; Rothstein, R.; Costantini, F.

    1990-01-01

    To test the feasibility of transferring yeast artificial chromosomes (YACs) into mammalian cells, we modified a YAC that carries approximately 450 kilobases (kb) of human DNA, by inserting a neomycin-resistance gene. Saccharomyces cerevisiae cells carrying this YAC were fused by polyethylene glycol to mouse L cells and G418-resistant colonies were obtained. A high percentage of these clones contained virtually intact YAC sequences as revealed by "Alu fingerprint" analysis and restriction enzy...

  13. Ethanol Production by Saccharomyces cerevisiae Immobilized in Hollow-Fiber Membrane Bioreactors

    OpenAIRE

    Inloes, Douglas S.; Taylor, Dean P.; Cohen, Stanley N; Michaels, Alan S.; Robertson, Channing R.

    1983-01-01

    Saccharomyces cerevisiae ATCC 4126 was grown within the macroporous matrix of asymmetric-walled polysulfone hollow-fiber membranes and on the exterior surfaces of isotropic-walled polypropylene hollow-fiber membranes. Nutrients were supplied and products were removed by single-pass perfusion of the fiber lumens. Growth of yeast cells within the macrovoids of the asymmetric-walled membranes attained densities of greater than 1010 cells per ml and in some regions accounted for nearly 100% of th...

  14. Evaluation of stress tolerance and fermentative behavior of indigenous Saccharomyces cerevisiae

    OpenAIRE

    Ramos, Cíntia Lacerda; Duarte, Whasley Ferreira; Freire, Ana Luiza; Dias, Disney Ribeiro; Eleutherio, Elis Cristina Araújo; Schwan, Rosane Freitas

    2013-01-01

    Sixty six indigenous Saccharomyces cerevisiae strains were evaluated in stressful conditions (temperature, osmolarity, sulphite and ethanol tolerance) and also ability to flocculate. Eighteen strains showed tolerant characteristics to these stressful conditions, growing at 42 °C, in 0.04% sulphite, 1 mol L?1 NaCl and 12% ethanol. No flocculent characteristics were observed. These strains were evaluated according to their fermentative performance in sugar cane juice. The conversion factors of ...

  15. A Recombinant Saccharomyces cerevisiae Strain Overproducing Mannoproteins Stabilizes Wine against Protein Haze?

    OpenAIRE

    González Ramos, Daniel; Cebollero, E.; González García, Ramón

    2008-01-01

    Stabilization against protein haze was one of the first positive properties attributed to yeast mannoproteins in winemaking. In previous work we demonstrated that deletion of KNR4 leads to increased mannoprotein release in laboratory Saccharomyces cerevisiae strains. We have now constructed strains with KNR4 deleted in two different industrial wine yeast backgrounds. This required replacement of two and three alleles of KNR4 for the EC1118 and T73-4 backgrounds, respectively, and the use of t...

  16. Morfologia do epitélio intestinal de codornas japonesas alimentadas com parede celular da Saccharomyces cerevisiae / Morphology of the intestinal epithelium of Japanese quail fed with cell wall Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    Marina Jorge de, Lemos; Lígia Fátima Lima, Calixto; Aparecida Alves do, Nascimento; Armando, Sales; Marcos Antônio José dos, Santos; Rômulo Jordão Neves, Aroucha.

    2013-12-01

    Full Text Available Objetivou-se com este trabalho avaliar os benefícios e o melhor nível de inclusão de parede celular de Saccharomyces cerevisiae (PCSC) na dieta sobre a morfologia intestinal de codornas japonesas (Coturnix coturnix japonica) durante a fase de produção. 400 codornas japonesas (42 a 154 dias de idade) [...] foram distribuídas em delineamento inteiramente casualizado, com cinco tratamentos e 10 repetições com oito aves cada. Foram utilizadas cinco dietas com diferentes níveis de parede celular de S. cerevisiae (0, 0,5, 1,0; 1,5; 2,0kg t-1). A dieta foi fornecida ad libitum durante todo o período experimental. As variáveis analisadas foram: altura e largura das vilosidades, relação altura/largura das vilosidades e profundidade da cripta intestinal. Altura, largura e proporção altura/largura das vilosidades intestinais foram influenciados pela inclusão de PCSc na dieta, enquanto que a profundidade das criptas não foi influenciada pela adição de PCSc. A inclusão de parede celular de S. cerevisiae na dieta até 1,7kg t-1 trouxe alterações positivas na morfologia do epitélio intestinal de codornas japonesas (C. c. japonica) na fase de produção. Abstract in english Objective of this research was to evaluate the benefits and the best level of cell wall of Saccharomyces cerevisiae (PCSc) added on the diet, on intestinal morphology of Japanese quail (Coturnix coturnix japonica), during the production phase. 400 Japanese quails (42 to 154 days of age), were distri [...] buted in a complete random design, with five treatments and 10 replicates with 8 birds each. It was used five diets with different levels of cell wall of S. cerevisiae (0; 0.5; 1.0; 1.5; 2.0kg t-1). Diet was fed ad libitum during all the experimental period. The variables were: height and width of the villus, width / height ratio of the villi and depth of the intestinal crypt. Height, width and height and width ratio of the intestinal villi were influenced by the inclusion of PCSc in the diet, while the crypt depth was not influenced by the addition of PCSc. The inclusion of the cell wall of S. cerevisiae in the diet up to 1.7kg t-1 brought positive changes in the morphology of the intestinal epithelium of Japanese quail (C. c. japonica) in the production phase.

  17. Investigation of nutrient sensing in the yeast Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine

    2006-01-01

    Gæren Saccharomyces cerevisiae har udviklet komplekse regulatoriske systemer til at kontrollere ekspression af de proteiner, der importerer næringsstoffer, således at disse kun bliver produceret, når der er brug for dem. Dette er tilfældet for hexose-transportører samt aminosyre-transportører (disse bliver også kaldt amino acid permeases (AAPs)). Deres ekspression induceres på det transkriptionelle niveau efter at ekstracellulære næringsstoffer, henholdsvis glukose og aminosyrer, bliver detekteret af sensor-proteiner, som sidder i plasmamembranen. Aminosyrer bliver detekteres af den såkaldte SPS (Ssy1p-Ptr3p-Ssy5p) sensor, og et signal genereres og bliver transmitteret via de homologe transkriptionsfaktorer Stp1p og Stp2p. Stp1p og Stp2p undergår endoproteolytisk kløvning i cytoplasma og migrerer derefter til cellekernen, hvor de binder til promoter-DNA ved flere AAP gener, hvilket medfører transkriptionel induktion. For at kunne bekræfte eller identificere nye gener som reguleres via SPS-systemet, blev der udført global transkriptionel profilering af vildtype stammer samt af stammer deleterede for enten SSY1 eller STP1 og STP2, både med og uden aminosyren L-citrullin i mediet. L-citrulline kan ikke optages af disse stammer, da de mangler GAP1 (General Amino acid Permease). Det blev bekræftet, at AAP generne TAT1, BAP2, BAP3 og PTR2 er under kontrol af aminosyre induktionsvejen, mens AGP2 blev identificeret som et nyt gen under kontrol af denne mekanisme. Den globale transkriptionsanalyse viste at 46 gener induceres af L-citrullin, afhængigt af Ssy1p og Stp1p/Stp2p. Sekvenssammenligning af promoterregionerne muliggjorde en mere præcis definition af den tidligere beskrevet Upstream Activating Sequence (UASaa). Udover effekten på AAP gener, viste ssy1? og stp1? stp2? mutanter mange andre transkriptionelle fænotyper, såsom øget ekspression af gener under kontrol af Nitrogen Catabolite Repression og gener involverede i stress respons. F-box proteinet Grr1p, som også spiller en rolle i regulering af cellecyklus og glukose induktion af heksose transportørgener, er nødvendig for at aminosyre induktion kan finde sted. Hel-genom transkriptionsanalyser af en vildtype stamme og en grr1? stamme med og uden L-citrullin blev udført. Dataanalyse viste at aminosyre induktion af AAP generne AGP1, BAP2, BAP3, DIP5, TAT1, og GNP1 er helt afhængig af tilstedeværelsen af GRR1. Sammenligningen af de to stammers transkriptionelle profiler viste at, når GRR1 er slået ud, transkription af mange gener til enzymer i den centrale karbon metabolisme øges. Promoteranalyse viste at mange af de gener med øget transkription har mulige Mig1p og/eller Msn2p-Msn4p bindingelementer. Den øgede ekspression af glukose-represserede gener i grr1? stammen kan være en indirekte konsekvens af den begrænsede glukose optagelse som forventes i denne mutant på grund af formindsket ekspression af flere hexose transportører. I et forsøg på at identificere nye komponenter i SPS-signaltransduktionsmekanismen, blev en transposon samling screenet for mutanter med (konstitutive) transkriptionel induktion af AAP gener, det vil sige, mutanter, i hvilke signaleringsvejen er aktiv selv uden aminosyre i mediet. Flere transposoner blev fundet i RTS1 locus. RTS1 koder en af de to regulatoriske enheder af protein fosfatase 2A, som er kendt i gær. RTS1 blev slået ud, og dette medførte konstitutiv aktivering af AGP1 og BAP2 promotorer. Dette var afhængigt af SSY1, PTR3, SSY5, GRR1 eller STP1, STP2 og deres homolog STP3. Den forøgede transkription fra AGP1 og BAP2 promotorer i rts1? celler ser ud til at skyldes forøget processering af Stp1p. Med dette arbejde blev der identificeret nye gener som reguleres via SPS-signalnetværket og konsensussekvensen af UASaa involveret i aminosyre induktion blev defineret mere præcist. Det er blevet bekræftet at Grr1p er involveret i denne vej og effekterne af grr1? mutationen blev undersøgt på hel-genom transkriptionelt niveau. Derudover, blev der identificeret en ny komponent af signa

  18. In silico modeling of cation homeostasis in Saccharomyces cerevisiae

    OpenAIRE

    Gerber, Susanne

    2011-01-01

    Die toxische Wirkung von Kationen ist verantwortlich für eine Reihe biologischer und pathologischer Erscheinungen. Zu den übergreifenden Zielen des Gesamtvorhabens wurden als wissenschaftliche Arbeiten i) die Analyse, graphische Darstellung und darauf basierende Gewichtung spezifischer genomischer Promotor-Regionen, ii) die Verarbeitung, Auswertung und genomweite Analyse von Mikro-Array Experimenten über die Auswirkung verschiedener Schwermetalle auf S. cerevisiae, iii) Mitarbeit an einer Si...

  19. Removal of lead, mercury and nickel using the yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Cherlys Infante J.

    2014-06-01

    Full Text Available Objective. In this study the biomass of the yeast Saccharomyces cerevisiae was used to remove lead, mercury and nickel in the form of ions dissolved in water. Materials and methods. Synthetic solutions were prepared containing the three heavy metals, which were put in contact with viable microorganisms at different conditions of pH, temperature, aeration and agitation. Results. Both individual variables and the interaction effects influenced the biosorption process. Throughout the experimental framework it was observed that the biomass of Saccharomyces cerevisiae removed a higher percentage of lead (86.4% as compared to mercury and nickel (69.7 and 47.8% respectively. When the pH was set at a value of 5 the effect was positive for all three metals. Conclusions. pH was the variable that had a greater influence on the biosorption of lead on the biomass of Saccharomyces cerevisiae. The affinity of the heavy metals for the biomass followed the order Pb>Hg>Ni.

  20. Crystallization and preliminary X-ray diffraction analysis of motif N from Saccharomyces cerevisiae Dbf4

    International Nuclear Information System (INIS)

    To understand the role of the Cdc7–Dbf4 complex in checkpoint responses, a fragment of Saccharomyces cerevisiae Dbf4 encompassing motif N was isolated, overproduced and crystallized. The Cdc7–Dbf4 complex plays an instrumental role in the initiation of DNA replication and is a target of replication-checkpoint responses in Saccharomyces cerevisiae. Cdc7 is a conserved serine/threonine kinase whose activity depends on association with its regulatory subunit, Dbf4. A conserved sequence near the N-terminus of Dbf4 (motif N) is necessary for the interaction of Cdc7–Dbf4 with the checkpoint kinase Rad53. To understand the role of the Cdc7–Dbf4 complex in checkpoint responses, a fragment of Saccharomyces cerevisiae Dbf4 encompassing motif N was isolated, overproduced and crystallized. A complete native data set was collected at 100 K from crystals that diffracted X-rays to 2.75 Å resolution and structure determination is currently under way

  1. Pengaruh Media Tumbuh terhadap Kadar Protein Saccharomyces cerevisiae dalam Pembuatan Protein Sel Tunggal

    Directory of Open Access Journals (Sweden)

    RATNA SETYANINGSIH

    2004-11-01

    Full Text Available The aim of this research was to examine the influence of difference growth media, i. e. tofu liquid waste, tofu solid waste, and coconut water in various composition and Yeast Extract Peptone Dextrose (YEPD, to protein contents of Saccharomyces cerevisiae in Single Cell Protein (SCP production. The framework of this research was that tofu liquid waste, tofu solid waste, and coconut water were containing a lot of carbons, nitrogens, minerals, and vitamin that could be used as growth medium of S. cerevisiae to produce SCP, which was commonly used. The medium from tofu liquid waste and the coconut water were made by ratio 2:1, 1:1, 1:2 and added with tofu solid waste 1.5 g and 2.5 g. Then, the measurement of pH medium, the amount of cell, cell dried weight, and the protein content in S. cerevisiae was done. The measurement of protein content was done by Lowry method. The result of the research showed that growth media influenced protein content of S. cerevisiae. Protein content of S. cerevisiae cultured in tofu liquid waste- coconut water was lower then in YEPD medium. The protein content of S. cerevisiae cultured in tofu liquid waste and coconut water ratio 1:2, added with 2.5 g tofu solid waste was higher then in other medium composition.

  2. Saccharomyces cerevisiae : a model to uncover molecular mechanisms for yeast biofilm biology.

    DEFF Research Database (Denmark)

    Bojsen, Rasmus K; Andersen, Kaj Scherz

    2012-01-01

    Microbial biofilms can be defined as multi-cellular aggregates adhering to a surface and embedded in an extracellular matrix (ECM). The nonpathogenic yeast, Saccharomyces cerevisiae, follows the common traits of microbial biofilms with cell-cell and cell-surface adhesion. S. cerevisiae is shown to produce an ECM and respond to quorum sensing, and multi-cellular aggregates have lowered susceptibility to antifungals. Adhesion is mediated by a family of cell surface proteins of which Flo11 has been shown to be essential for biofilm development. FLO11 expression is regulated via a number of regulatory pathways including the protein kinase A and a mitogen-activated protein kinase pathway. Advanced genetic tools and resources have been developed for S. cerevisiae including a deletion mutant-strain collection in a biofilm-forming strain background and GFP-fusion protein collections. Furthermore, S. cerevisiae biofilm is well applied for confocal laser scanning microscopy and fluorophore tagging of proteins, DNA and RNA. These techniques can be used to uncover the molecular mechanisms for biofilm development, drug resistance and for the study of molecular interactions, cell response to environmental cues, cell-to-cell variation and niches in S. cerevisiae biofilm. Being closely related to Candida species, S. cerevisiae is a model to investigate biofilms of pathogenic yeast.

  3. Efeito do nitrito sobre a fermentação alcoólica realizada por Saccharomyces cerevisiae / Effect of nitrite on alcoholic fermentation carried out with Saccharomyces cerevisiae

    Scientific Electronic Library Online (English)

    L.E., Gutierrez; V.F. de Martin, Orelli.

    Full Text Available O efeito de concentrações de até 80 ppm de nitrito sobre a fermentação alcoólica foi estudado com levedura de panificação (Saccharomyces cerevisiae). Houve aumento no tempo de fermentação com adição de nitrito sem afetar a produção de etanol. Com a adição de 60 e 80 ppm de NO2-, ocorreu redução na v [...] iabilidade celular e brotamento acompanhada por aumento no acúmulo de trealose e glicogênio. Aumentando a concentração de nitrito houve aumento no álcool n-propílico e redução nos teores de álcoois isobutílico e isoamílico. Abstract in english The effect of nitrite up to 80 ppm on alcoholic fermentation was studied with baker's yeast (Saccharomyces cerevisiae). There was an increase in fermentation time but not effect on ethanol yield. With the addition of 60 and 80 ppm NO2- there was a reduction on cell viabilitty and budding with corres [...] pondent increase on trehalose and glycogen accumulation. Increasing nitrite concentration resulted in increase on n-propilic alcohol level and a reduction on isobutilic and isoamilic alcohols content.

  4. Parameter Optimization for Enhancement of Ethanol Yield by Atmospheric Pressure DBD-Treated Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    In this study, Saccharomyces cerevisiae (S. cerevisiae) was exposed to dielectric barrier discharge plasma (DBD) to improve its ethanol production capacity during fermentation. Response surface methodology (RSM) was used to optimize the discharge-associated parameters of DBD for the purpose of maximizing the ethanol yield achieved by DBD-treated S. cerevisiae. According to single factor experiments, a mathematical model was established using Box-Behnken central composite experiment design, with plasma exposure time, power supply voltage, and exposed-sample volume as impact factors and ethanol yield as the response. This was followed by response surface analysis. Optimal experimental parameters for plasma discharge-induced enhancement in ethanol yield were plasma exposure time of 1 min, power voltage of 26 V, and an exposed sample volume of 9 mL. Under these conditions, the resulting yield of ethanol was 0.48 g/g, representing an increase of 33% over control. (plasma technology)

  5. A new biological test of water toxicity-yeast Saccharomyces cerevisiae conductometric test.

    Science.gov (United States)

    Dolezalova, Jaroslava; Rumlova, Lubomira

    2014-11-01

    This new biological test of water toxicity is based on monitoring of specific conductivity changes of yeast Saccharomyces cerevisiae suspension as a result of yeast fermentation activity inhibition in toxic conditions. The test was verified on ten substances with various mechanisms of toxic effect and the results were compared with two standard toxicity tests based on Daphnia magna mobility inhibition (EN ISO 6341) and Vibrio fischeri bioluminescence inhibition (EN ISO 11348-2) and with the results of the S. cerevisiae lethal test (Rumlova and Dolezalova, 2012). The new biological test - S. cerevisiae conductometric test - is an express method developed primarily for field conditions. It is applicable in case of need of immediate information about water toxicity. Fast completion is an advantage of this test (time necessary for test completion is about 60min), the test is simple and the test organism - dried instant yeast - belongs among its biggest advantages because of its long-term storage life and broad availability. PMID:25461558

  6. Biopharmaceutical protein production bySaccharomyces cerevisiae: current state and future prospects

    DEFF Research Database (Denmark)

    Huang, Mingtao; Bao, Jichen

    2014-01-01

    In the past few decades there has been an increasing demand of biopharmaceutical proteins in the market. Several types of cell factories are applied to produce different pharmaceutical proteins. However, manufacturers prefer to use a few favorable biological platforms to undertake the production tasks with low cost, high productivity and proper post-translational modifications. The yeast Saccharomyces cerevisiae is one of these preferred cell factories as it meets many of the requirements. There are several reports on improvement of recombinant protein production by S. cerevisiae through rational engineering of different stages of the protein secretion pathway. However, recent developments of new technologies like systems biology and synthetic biology open new doors to design S. cerevisiae as an ideal production platform.

  7. Effect of live Saccharomyces cerevisiae feeding on serum biochemistry in early weaned cross bred piglets

    Directory of Open Access Journals (Sweden)

    Sachin Kumar

    Full Text Available Aim: To assess the effect of feeding live Saccharomyces cerevisiae on serum biochemistry in early weaned cross bred (Landrace × Desi piglets Materials and Methods: 48 piglets assigned to four different groups (T1, T2, T3 and T4: n=12 following completely randomized design. T1 and T2 were weaned at age of 28 days while T3 and T4 were weaned at age of 42 days. T1 and T3 were fed basal diet without S. cerevisiae, however, T2 and T4 were supplemented with live S. cerevisiae (200 g/d/h containing 2- 3×106 cfu/g. Results: The period-wise comparison of mean values of serum albumin and globulin were similar, however, period-wise comparison of protein was significant. The mean glucose value of T4 was statistically higher than T1 and comparable with T2 and T3. The serum total cholesterol level was found to be lower in T2 and T4 as compared to T1 and T3. Conclusion: Results of study suggest that supplementation of live Saccharomyces cerevisiae was effective in improving the health status of early weaned piglets. [Vet World 2012; 5(11.000: 663-666

  8. Ethanol Production from Sago Waste Using Saccharomyces cerevisiae Vits-M1

    Directory of Open Access Journals (Sweden)

    D. Subashini

    2011-01-01

    Full Text Available The present study deals with the biotechnological production of ethanol from sago waste materials. As petroleum has become depleted, renewable energy production has started to gain attention all over the world, including the production of ethanol from sago wastes. In our research we have standardized the production of ethanol from sago wastes using Saccharomyces cerevisiae strain isolated from molasses. The production of ethanol was carried out by means of simultaneous saccharification with acids, followed by fermentation. The yeast strains were isolated from either batter or molasses and the taxonomy was studied by phenotypic characters in comparison with the standard strain Saccharomyces cerevisiae MTCC 173. Among the two isolated strains, S. cerevisiae VITS-M1 isolated from molasses showed better survival rate in different sugars such as glucose, sucrose, maltose and galactose except lactose; it also showed better survival rate at high ethanol concentration and at acidic pH. The saccharification process of sago liquid waste and solid waste was standardized using hydrochloric acid and sulphuric acid under different treatments. The fermented product, ethanol was distilled using laboratory model distillation unit and measured qualitatively using gas chromatography in comparison with the standard analytical grade ethanol. The overall experimental data indicates that the sago liquid waste yielded more ethanol by simultaneous saccharification with 0.3N HCl and 0.3N H2SO4 and fermentation with the S. cerevisiae VITS-M1 isolated from molasses.

  9. Bioethanol production by a flocculent hybrid, CHFY0321 obtained by protoplast fusion between Saccharomyces cerevisiae and Saccharomyces bayanus

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gi-Wook; Kang, Hyun-Woo; Kim, Yule [Changhae Institute of Cassava and Ethanol Research, Changhae Ethanol Co., LTD, Palbok-Dong 829, Dukjin-Gu, Jeonju 561-203 (Korea); Um, Hyun-Ju; Kim, Mina; Kim, Yang-Hoon [Department of Microbiology, Chungbuk National University, 410 Sungbong-Ro, Heungduk-Gu, Cheongju 361-763 (Korea)

    2010-08-15

    Fusion hybrid yeast, CHFY0321, was obtained by protoplast fusion between non-flocculent-high ethanol fermentative Saccharomyces cerevisiae CHY1011 and flocculent-low ethanol fermentative Saccharomyces bayanus KCCM12633. The hybrid yeast was used together with the parental strains to examine ethanol production in batch fermentation. Under the conditions tested, the fusion hybrid CHFY0321 flocculated to the highest degree and had the capacity to ferment well at pH 4.5 and 32 C. Simultaneous saccharification and fermentation for ethanol production was carried out using a cassava (Manihot esculenta) powder hydrolysate medium containing 19.5% (w v{sup -1}) total sugar in a 5 l lab scale jar fermenter at 32 C for 65 h with an agitation speed of 2 Hz. Under these conditions, CHFY0321 showed the highest flocculating ability and the best fermentation efficiency for ethanol production compared with those of the wild-type parent strains. CHFY0321 gave a final ethanol concentration of 89.8 {+-} 0.13 g l{sup -1}, a volumetric ethanol productivity of 1.38 {+-} 0.13 g l{sup -1} h{sup -1}, and a theoretical yield of 94.2 {+-} 1.58%. These results suggest that CHFY0321 exhibited the fermentation characteristics of S. cerevisiae CHY1011 and the flocculent ability of S. bayanus KCCM12633. Therefore, the strong highly flocculent ethanol fermentative CHFY0321 has potential for improving biotechnological ethanol fermentation processes. (author)

  10. Bioethanol production by a flocculent hybrid, CHFY0321 obtained by protoplast fusion between Saccharomyces cerevisiae and Saccharomyces bayanus

    International Nuclear Information System (INIS)

    Fusion hybrid yeast, CHFY0321, was obtained by protoplast fusion between non-flocculent-high ethanol fermentative Saccharomyces cerevisiae CHY1011 and flocculent-low ethanol fermentative Saccharomyces bayanus KCCM12633. The hybrid yeast was used together with the parental strains to examine ethanol production in batch fermentation. Under the conditions tested, the fusion hybrid CHFY0321 flocculated to the highest degree and had the capacity to ferment well at pH 4.5 and 32 oC. Simultaneous saccharification and fermentation for ethanol production was carried out using a cassava (Manihot esculenta) powder hydrolysate medium containing 19.5% (w v-1) total sugar in a 5 l lab scale jar fermenter at 32 oC for 65 h with an agitation speed of 2 Hz. Under these conditions, CHFY0321 showed the highest flocculating ability and the best fermentation efficiency for ethanol production compared with those of the wild-type parent strains. CHFY0321 gave a final ethanol concentration of 89.8 ± 0.13 g l-1, a volumetric ethanol productivity of 1.38 ± 0.13 g l-1 h-1, and a theoretical yield of 94.2 ± 1.58%. These results suggest that CHFY0321 exhibited the fermentation characteristics of S. cerevisiae CHY1011 and the flocculent ability of S. bayanus KCCM12633. Therefore, the strong highly flocculent ethanol fermentative CHFY0321 has potential for improving biotechnological ethanol fermentation processes.

  11. Activation of waste brewer's yeast Saccharomyces cerevisiae for bread production

    OpenAIRE

    Popov Stevan D.; Dodi? Siniša N.; Mastilovi? Jasna S.; Dodi? Jelena M.; Popov-Ralji? Jovanka V.

    2005-01-01

    The waste brewer's yeast S. cerevisiae (activated and non-activated) was compared with the commercial baker's yeast regarding the volume of developed gas in dough, volume and freshness stability of produced bread. The activation of waste brewer's yeast resulted in the increased volume of developed gas in dough by 100% compared to non-activated brewer's yeast, and the obtained bread is of more stable freshness compared to bread produced with baker's yeast. The activation of BY affects positive...

  12. Impact of Acute Metal Stress in Saccharomyces cerevisiae

    OpenAIRE

    2014-01-01

    Although considered as essential cofactors for a variety of enzymatic reactions and for important structural and functional roles in cell metabolism, metals at high concentrations are potent toxic pollutants and pose complex biochemical problems for cells. We report results of single dose acute toxicity testing in the model organism S. cerevisiae. The effects of moderate toxic concentrations of 10 different human health relevant metals, Ag+, Al3+, As3+, Cd2+, Co2+, Hg2+, Mn2+, Ni2+, V3+, and ...

  13. A novel calcineurin-independent activity of cyclosporin A in Saccharomyces cerevisiae.

    Science.gov (United States)

    Singh-Babak, Sheena D; Shekhar, Tanvi; Smith, Andrew M; Giaever, Guri; Nislow, Corey; Cowen, Leah E

    2012-10-01

    Fungi rely on regulatory networks to coordinate sensing of environmental stress with initiation of responses crucial for survival. Antifungal drugs are a specific type of environmental stress with broad clinical relevance. Small molecules with antifungal activity are ubiquitous in the environment, and are produced by a myriad of microbes in competitive natural communities. The echinocandins are fungal fermentation products and the most recently developed class of antifungals, with those in clinical use being semisynthetic derivatives that target the fungal cell wall by inhibiting 1,3-?-D-glucan synthase. Recent studies implicate the protein phosphatase calcineurin as a key regulator of cellular stress responses required for fungal survival of echinocandin-induced cell wall stress. Pharmacological inhibition of calcineurin can be achieved using the natural product and immunosuppressive drug cyclosporin A, which inhibits calcineurin by binding to the immunophilin Cpr1. This drug-protein complex inhibits the interaction between the regulatory and catalytic subunits of calcineurin, an interaction necessary for calcineurin function. Here, we report on potent activity of cyclosporin A when combined with the echinocandin micafungin against the model yeast Saccharomyces cerevisiae that is independent of its known mechanism of action of calcineurin inhibition. This calcineurin-independent synergy does not involve any of the 12 immunophilins known in yeast, individually or in combination, and is not mediated by any of the multidrug transporters encoded or controlled by YOR1, SNQ2, PDR5, PDR10, PDR11, YCF1, PDR15, ADP1, VMR1, NFT1, BPT1, YBT1, YNR070w, YOL075c, AUS1, PDR12, PDR1 and/or PDR3. Genome-wide haploinsufficiency profiling (HIP) and homozygous deletion profiling (HOP) strongly implicate the cell wall biosynthesis and integrity pathways as being central to the calcineurin-independent activity of cyclosporin A. Thus, systems level chemical genomic approaches implicate key cellular pathways in a novel mechanism of antifungal drug synergy. PMID:22751784

  14. Topical reversion at the HIS1 locus of Saccharomyces cerevisiae. A tale of three mutants.

    Science.gov (United States)

    von Borstel, R C; Savage, E A; Wang, Q; Hennig, U G; Ritzel, R G; Lee, G S; Hamilton, M D; Chrenek, M A; Tomaszewski, R W; Higgins, J A; Tenove, C J; Liviero, L; Hastings, P J; Korch, C T; Steinberg, C M

    1998-04-01

    Mutants of the HIS1 locus of the yeast Saccharomyces cerevisiae are suitable reporters for spontaneous reversion events because most reversions are topical, that is, within the locus itself. Thirteen mutations of his1-1 now have been identified with respect to base sequence. Revertants of three mutants and their spontaneous reversion rates are presented: (1) a chain termination mutation (his1-208, née his1-1) that does not revert by mutations of tRNA loci and reverts only by intracodonic suppression; (2) a missense mutation (his1-798, née his1-7) that can revert by intragenic suppression by base substitutions of any sort, including a back mutation as well as one three-base deletion; and (3) a -1 frameshift mutation (his1-434, née his1-19) that only reverts topically by +1 back mutation, +1 intragenic suppression, or a -2 deletion. Often the +1 insertion is accompanied by base substitution events at one or both ends of a run of A's. Missense suppressors of his1-798 are either feeders or nonfeeders, and at four different locations within the locus, a single base substitution encoding an amino acid alteration will suffice to turn the nonfeeder phenotype into a feeder phenotype. Late-appearing revertants of his1-798 were found to be slowly growing leaky mutants rather than a manifestation of adaptive mutagenesis. Spontaneous revertants of his1-208 and his1-434 produced no late-arising colonies. PMID:9560384

  15. Protein carboxyl methylation in Saccharomyces cerevisiae: evidence for STE14-dependent and STE14-independent pathways.

    Science.gov (United States)

    Hrycyna, C A; Yang, M C; Clarke, S

    1994-08-16

    We incubated yeast cells (Saccharomyces cerevisiae) with the methyl donor S-adenosyl-L-[methyl-3H]methionine and then fractionated their cellular components by gel electrophoresis in sodium dodecyl sulfate. By analyzing gel slices for [3H]methyl esters by a vapor-phase diffusion assay, we detect major methyl-esterified species that migrate at apparent polypeptide sizes of 24 and 22 kDa and minor species of 49, 38, 35, 33, 31, and 26 kDa. Incubation of extracts from labeled cells with ribonuclease A or proteinase K revealed that the 24- and 22-kDa species represent methyl-esterified RNAs, whereas the other species are methyl-esterified polypeptides. The 38-, 33-, 31-, and 26-kDa polypeptides were not methyl-esterified in an isogenic yeast strain lacking the STE14 gene encoding a C-terminal isoprenylcysteine methyltransferase, suggesting that they are substrates for the STE14 methyltransferase. On the other hand, the amount of the methylated 49-kDa polypeptide is reduced in the ste14 mutant, indicating that at least two methylated polypeptides are present--one a substrate of the STE14 methyltransferase and one a substrate of a STE14-independent methyltransferase. The 35-kDa polypeptide also appears to be methylated by a STE14-independent methyltransferase. When cells were incubated in the presence of the protein synthesis inhibitor cycloheximide, little or no methylation of the STE14-dependent species was detected while the methylation of the STE14-independent substrates was unaffected. Pulse-chase studies revealed significant turnover of all of the methylated species in a 4-h period, with the exception of the 38-kDa polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8068661

  16. Whole genome sequencing of Saccharomyces cerevisiae: from genotype to phenotype for improved metabolic engineering applications

    Directory of Open Access Journals (Sweden)

    Asadollahi Mohammad A

    2010-12-01

    Full Text Available Abstract Background The need for rapid and efficient microbial cell factory design and construction are possible through the enabling technology, metabolic engineering, which is now being facilitated by systems biology approaches. Metabolic engineering is often complimented by directed evolution, where selective pressure is applied to a partially genetically engineered strain to confer a desirable phenotype. The exact genetic modification or resulting genotype that leads to the improved phenotype is often not identified or understood to enable further metabolic engineering. Results In this work we performed whole genome high-throughput sequencing and annotation can be used to identify single nucleotide polymorphisms (SNPs between Saccharomyces cerevisiae strains S288c and CEN.PK113-7D. The yeast strain S288c was the first eukaryote sequenced, serving as the reference genome for the Saccharomyces Genome Database, while CEN.PK113-7D is a preferred laboratory strain for industrial biotechnology research. A total of 13,787 high-quality SNPs were detected between both strains (reference strain: S288c. Considering only metabolic genes (782 of 5,596 annotated genes, a total of 219 metabolism specific SNPs are distributed across 158 metabolic genes, with 85 of the SNPs being nonsynonymous (e.g., encoding amino acid modifications. Amongst metabolic SNPs detected, there was pathway enrichment in the galactose uptake pathway (GAL1, GAL10 and ergosterol biosynthetic pathway (ERG8, ERG9. Physiological characterization confirmed a strong deficiency in galactose uptake and metabolism in S288c compared to CEN.PK113-7D, and similarly, ergosterol content in CEN.PK113-7D was significantly higher in both glucose and galactose supplemented cultivations compared to S288c. Furthermore, DNA microarray profiling of S288c and CEN.PK113-7D in both glucose and galactose batch cultures did not provide a clear hypothesis for major phenotypes observed, suggesting that genotype to phenotype correlations are manifested post-transcriptionally or post-translationally either through protein concentration and/or function. Conclusions With an intensifying need for microbial cell factories that produce a wide array of target compounds, whole genome high-throughput sequencing and annotation for SNP detection can aid in better reducing and defining the metabolic landscape. This work demonstrates direct correlations between genotype and phenotype that provides clear and high-probability of success metabolic engineering targets. The genome sequence, annotation, and a SNP viewer of CEN.PK113-7D are deposited at http://www.sysbio.se/cenpk.

  17. Whole genome sequencing of Saccharomyces cerevisiae: from genotype to phenotype for improved metabolic engineering applications

    DEFF Research Database (Denmark)

    Otero, José Manuel; Vongsangnak, Wanwipa

    2010-01-01

    BACKGROUND: The need for rapid and efficient microbial cell factory design and construction are possible through the enabling technology, metabolic engineering, which is now being facilitated by systems biology approaches. Metabolic engineering is often complimented by directed evolution, where selective pressure is applied to a partially genetically engineered strain to confer a desirable phenotype. The exact genetic modification or resulting genotype that leads to the improved phenotype is often not identified or understood to enable further metabolic engineering. RESULTS: In this work we performed whole genome high-throughput sequencing and annotation can be used to identify single nucleotide polymorphisms (SNPs) between Saccharomyces cerevisiae strains S288c and CEN.PK113-7D. The yeast strain S288c was the first eukaryote sequenced, serving as the reference genome for the Saccharomyces Genome Database, while CEN.PK113-7D is a preferred laboratory strain for industrial biotechnology research. A total of 13,787 high-quality SNPs were detected between both strains (reference strain: S288c). Considering only metabolic genes (782 of 5,596 annotated genes), a total of 219 metabolism specific SNPs are distributed across 158 metabolic genes, with 85 of the SNPs being nonsynonymous (e.g., encoding amino acid modifications). Amongst metabolic SNPs detected, there was pathway enrichment in the galactose uptake pathway (GAL1, GAL10) and ergosterol biosynthetic pathway (ERG8, ERG9). Physiological characterization confirmed a strong deficiency in galactose uptake and metabolism in S288c compared to CEN.PK113-7D, and similarly, ergosterol content in CEN.PK113-7D was significantly higher in both glucose and galactose supplemented cultivations compared to S288c. Furthermore, DNA microarray profiling of S288c and CEN.PK113-7D in both glucose and galactose batch cultures did not provide a clear hypothesis for major phenotypes observed, suggesting that genotype to phenotype correlations are manifested post-transcriptionally or post-translationally either through protein concentration and/or function. CONCLUSIONS: With an intensifying need for microbial cell factories that produce a wide array of target compounds, whole genome high-throughput sequencing and annotation for SNP detection can aid in better reducing and defining the metabolic landscape. This work demonstrates direct correlations between genotype and phenotype that provides clear and high-probability of success metabolic engineering targets. The genome sequence, annotation, and a SNP viewer of CEN.PK113-7D are deposited at http://www.sysbio.se/cenpk.

  18. [Functional expression of an omega-3 fatty acid desaturase gene from Glycine max in Saccharomyces cerevisiae].

    Science.gov (United States)

    Zhang, Hong-Tao; Yang, Jia-Sen; Shan, Lei; Bi, Yu-Ping

    2006-01-01

    Alpha-linolenic acid(ALA, C18:3delta9,12,15 ) is an essential fatty acid which has many sanitary functions to human. However, its contents in diets are often not enough. In plants, omega-3 fatty acid desaturases(FAD) catalyze linoleic acid(LA, C18:2delta9,12) into ALA. The seed oil of Glycine max contains high level of ALA. To investigate the functions of Glycine max omega-3FAD, the cDNA of GmFAD3 C was amplified by RT-PCR from immature seeds, then cloned into the shuttle expression vector p416 to generate the recombinant vector p4GFAD3C. The resulting vector was transformed into Saccharomyces cerevisiae K601 throuth LiAc method. The positive clones were screened on the CM(Ura-) medium and identified by PCR, and then cultured in CM (Ura-) liquid medium with exogenous LA in 20 degrees C for three days. The intracellular fatty acid composition of the engineering strain Kp416 and Kp4GFAD3C was analyzed by gas chromatography (GC). A novel peak in strain Kp4GFAD3C was detected,which was not detectable in control, Comparison of the retention times of the newly yielded peak with that of authentic standard indicated that the fatty acid is ALA. The content of ALA reached to 3.1% of the total fatty acid in recombinant strain, the content of LA correspondingly decreased from 22% to 16.2% by contrast. It was suggested that the protein encoded by GmFAD3 C can specifically catalyze 18 carbon PUFA substrate of LA into ALA by taking off hydrogen atoms at delta15 location. In this study, we expressed a Glycine max omega-3 fatty acid desaturase gene in S. cerevisiae; An efficient and economical yeast expressing system(K601-p416 system) which is suitable for the expression of FAD was built. PMID:16572837

  19. Loss of lager specific genes and subtelomeric regions define two different Saccharomyces cerevisiae lineages for Saccharomyces pastorianus Group I and II strains.

    Science.gov (United States)

    Monerawela, Chandre; James, Tharappel C; Wolfe, Kenneth H; Bond, Ursula

    2015-03-01

    Lager yeasts, Saccharomyces pastorianus, are interspecies hybrids between S. cerevisiae and S. eubayanus and are classified into Group I and Group II clades. The genome of the Group II strain, Weihenstephan 34/70, contains eight so-called 'lager-specific' genes that are located in subtelomeric regions. We evaluated the origins of these genes through bioinformatic and PCR analyses of Saccharomyces genomes. We determined that four are of cerevisiae origin while four originate from S. eubayanus. The Group I yeasts contain all four S. eubayanus genes but individual strains contain only a subset of the cerevisiae genes. We identified S. cerevisiae strains that contain all four cerevisiae 'lager-specific' genes, and distinct patterns of loss of these genes in other strains. Analysis of the subtelomeric regions uncovered patterns of loss in different S. cerevisiae strains. We identify two classes of S. cerevisiae strains: ale yeasts (Foster O) and stout yeasts with patterns of 'lager-specific' genes and subtelomeric regions identical to Group I and II S. pastorianus yeasts, respectively. These findings lead us to propose that Group I and II S. pastorianus strains originate from separate hybridization events involving different S. cerevisiae lineages. Using the combined bioinformatic and PCR data, we describe a potential classification map for industrial yeasts. PMID:25673756

  20. Comportamento celular e resposta antioxidante diferenciados de Saccharomyces cerevisiae e de Saccharomyces chevalieri ao metavanadato de amónio Different cellular behaviour and antioxidant response of Saccharomyces cerevisiae and Saccharomyces chevalieri growing in presence of ammonium metavanadate

    Directory of Open Access Journals (Sweden)

    R. Ferreira

    2007-01-01

    Full Text Available A fermentação do vinho é um processo microbiológico complexo que requere a presença de leveduras adaptadas a condições de stresse. No ambiente celular de organismos aeróbios ocorrem naturalmente espécies reactivas de oxigénio (ROS como subprodutos da respiração mitocondrial. A elevada reactividade destas espécies químicas pode gerar danos moleculares que, em alguns casos, levam à morte celular. Em condições fisiológicas normais ou como resposta ao stresse oxidativo, a célula pode desencadear respostas adaptativas que envolvem mecanismos antioxidantes como os enzimas glutationo redutase (GR; EC 1.6.4.2 e catalases T (CAT T; EC 1.11.1.6 e A (CAT A; EC 1.11.1.6. O vanádio, um metal pesado presente em alguns fitofármacos, pode também com portar-se como um gerador de ROS, alterando o estado redox intracelular e exercendo efeitos nocivos em leveduras expostas a quantidade excessiva deste elemento. O principal objectivo deste trabalho foi comparar o efeito do metavanadato de amónio (NH4VO3, um sal pentavalente de vanádio, na viabilidade celular e nas actividades enzimáticas GR, CAT T e CAT A das leveduras vínicas Saccharomyces cerevisiae UE-ME3 e Saccharomyces chevalieri UE-ME1. Os resultados obtidos mostram que S. chevalieri UE-ME1 revelou menor tolerância ao NH4VO3 do que S. cerevisiae UE-ME3, uma vez que culturas de S. chevalieri não sobreviveram para valores de concentração do sal de vanádio superiores a 7,5 mM enquanto que células de S. cerevisiae mantiveram-se viáveis em presença de metavanadato de amónio 75 mM. As actividades enzimáticas estudadas apresentaram em S. chevalieri valores muito inferiores aos que foram determinados em S. cerevisiae embora em ambas as espécies de levedura o NH4VO3 pareça comportarse como um indutor de stresse oxidativo ao provocar um decréscimo significativo da actividade GR (PThe fermentation of wine is a complex microbiological process which requires yeast adaptation to stress conditions. In the cellular environment of aerobic organisms naturally reactive oxygen species (ROS occurs as by-products of mitochondrial respiration. The higher reactivity of these chemical species could cause molecular damages that in several cases induce cellular death. In common physiological conditions or as response to oxidative stress, the cell can generate adapted responses which involve antioxidants mechanisms as glutathione reductase (GR; EC 1.6.4.2 and catalase T (CAT T; EC 1.11.1.6 and A (CAT A; EC 1.11.1.6 enzymes. Vanadium, a heavy metal present in several pesticides could generate ROS changing the intracellular redox state and cause deleterious effects in yeasts exposed to higher levels of this element. The main objective of this work was to compare the effects of ammonium metavanadate (NH4VO3, a pentavalent salt of vanadium on cellular viability and GR, CAT T and CAT A activities of wine yeast Saccharomyces cerevisiae UE-ME3 and Saccharomyces chevalieri UE-ME1. The results obtained show that S. chevalieri UE-ME1 has lower tolerance to NH4VO3 than S. cerevisiae UE-ME3, since S. chevalieri cultures do not survive to concentration values of ammonium metavanadate higher than 7,5 mM, whereas S. cerevisiae cells are still viable in the presence of 75 mM. S. chevalieri has an enzymatic activity lower than S. cerevisiae, although for both yeast species NH4VO3 could behave as oxidative stress inductor, causing a significant decrease of GR activity (P<0,01 and a significant increase of CAT A activity (P<0,01. The results show also an increase of CAT T activity in both yeast species, which can be interpreted as a protective response to oxidative stress. Differences on response to amonium metavanadate by both species of Saccharomyces could be partially justified by more efficient antioxidant systems in S. cerevisiae UE-ME3.