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1

Kluyveromyces lactis maintains Saccharomyces cerevisiae intron-encoded splicing signals.  

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The actin (ACT) gene from the budding yeast Kluyveromyces lactis was cloned, and the nucleotide sequence was determined. The gene had a single intron 778 nucleotides in length which possessed the highly conserved splicing signals found in Saccharomyces cerevisiae introns. We demonstrated splicing of heterologous ACT transcripts in both K. lactis and S. cerevisiae.

Deshler, J. O.; Larson, G. P.; Rossi, J. J.

1989-01-01

2

Identification and analysis of a Saccharomyces cerevisiae copper homeostasis gene encoding a homeodomain protein.  

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Yeast metallothionein, encoded by the CUP1 gene, and its copper-dependent transcriptional activator ACE1 play a key role in mediating copper resistance in Saccharomyces cerevisiae. Using an ethyl methanesulfonate mutant of a yeast strain in which CUP1 and ACE1 were deleted, we isolated a gene, designated CUP9, which permits yeast cells to grow at high concentrations of environmental copper, most notably when lactate is the sole carbon source. Disruption of CUP9, which is located on chromosome...

Knight, S. A.; Tamai, K. T.; Kosman, D. J.; Thiele, D. J.

1994-01-01

3

Characterization of Saccharomyces cerevisiae genes encoding subunits of cyclic AMP-dependent protein kinase.  

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Mutations in the SRA1 or SRA3 gene eliminate the requirement for either RAS gene (RAS1 or RAS2) in Saccharomyces cerevisiae. We cloned SRA1 and SRA3 and determined their DNA sequences. SRA1 encodes the regulatory subunit of the cyclic AMP (cAMP)-dependent protein kinase and therefore is identical to REG1 and BCY1. This gene is not essential, but its deletion confers many traits: reduction of glycogen accumulation, temperature sensitivity, reduced growth rate on maltose and sucrose, inability ...

Cannon, J. F.; Tatchell, K.

1987-01-01

4

The Saccharomyces Cerevisiae Spt7 Gene Encodes a Very Acidic Protein Important for Transcription in Vivo  

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Mutations in the SPT7 gene of Saccharomyces cerevisiae originally were identified as suppressors of Ty and {delta small} insertion mutations in the 5' regions of the HIS4 and LYS2 genes. Other genes that have been identified in mutant hunts of this type have been shown to play a role in transcription. In this work we show that SPT7 is also important for proper transcription in vivo. We have cloned and sequenced the SPT7 gene and have shown that it encodes a large, acidic protein that is local...

Gansheroff, L. J.; Dollard, C.; Tan, P.; Winston, F.

1995-01-01

5

MAL11 and MAL61 encode the inducible high-affinity maltose transporter of Saccharomyces cerevisiae.  

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We have investigated the transport of maltose in a genetically defined maltose-fermenting strain of Saccharomyces cerevisiae carrying the MAL1 locus. Two kinetically different systems were identified: a high-affinity transporter with a Km of 4 mM and a low-affinity transporter with a Km of 70 to 80 mM. The high-affinity maltose transporter is maltose inducible and is encoded by the MAL11 (and/or MAL61) gene of the MAL1 (and/or MAL6) locus. The low-affinity maltose transporter is expressed con...

Cheng, Q.; Michels, C. A.

1991-01-01

6

Strain-dependent variation in carbon source regulation of nucleus-encoded mitochondrial proteins of Saccharomyces cerevisiae.  

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Nuclear genes encoding mitochondrial proteins are regulated by carbon source with significant heterogeneity among four Saccharomyces cerevisiae strains. This strain-dependent variation is seen both in respiratory capacity of the cells and in the expression of beta-galactosidase reporter fusions to the promoters of CYB2, CYC1, CYC3, MnSOD, and RPO41. PMID:7868614

Brown, T A; Trumpower, B L

1995-03-01

7

Strain-dependent variation in carbon source regulation of nucleus-encoded mitochondrial proteins of Saccharomyces cerevisiae.  

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Nuclear genes encoding mitochondrial proteins are regulated by carbon source with significant heterogeneity among four Saccharomyces cerevisiae strains. This strain-dependent variation is seen both in respiratory capacity of the cells and in the expression of beta-galactosidase reporter fusions to the promoters of CYB2, CYC1, CYC3, MnSOD, and RPO41.

Brown, T. A.; Trumpower, B. L.

1995-01-01

8

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

Science.gov (United States)

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

Teo, Wei Suong; Chang, Matthew Wook

2014-06-27

9

Characterization of a new multigene family encoding isomaltases in the yeast Saccharomyces cerevisiae, the IMA family.  

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It has been known for a long time that the yeast Saccharomyces cerevisiae can assimilate alpha-methylglucopyranoside and isomaltose. We here report the identification of 5 genes (YGR287c, YIL172c, YJL216c, YJL221c and YOL157c), which, similar to the SUCx, MALx, or HXTx multigene families, are located in the subtelomeric regions of different chromosomes. They share high nucleotide sequence identities between themselves (66-100%) and with the MALx2 genes (63-74%). Comparison of their amino acid sequences underlined a substitution of threonine by valine in region II, one of the four highly conserved regions of the alpha-glucosidase family. This change was previously shown to be sufficient to discriminate alpha-1,4- to alpha-1,6-glucosidase activity in YGR287c (Yamamoto, K., Nakayama, A., Yamamoto, Y., and Tabata, S. (2004) Eur. J. Biochem. 271, 3414-3420). We showed that each of these five genes encodes a protein with alpha-glucosidase activity on isomaltose, and we therefore renamed these genes IMA1 to IMA5 for IsoMAltase. Our results also illustrated that sequence polymorphisms among this family led to interesting variability of gene expression patterns and of catalytic efficiencies on different substrates, which altogether should account for the absence of functional redundancy for growth on isomaltose. Indeed, deletion studies revealed that IMA1/YGR287c encodes the major isomaltase and that growth on isomaltose required the presence of AGT1, which encodes an alpha-glucoside transporter. Expressions of IMA1 and IMA5/YJL216c were strongly induced by maltose, isomaltose, and alpha-methylglucopyranoside, in accordance with their regulation by the Malx3p-transcription system. The physiological relevance of this IMAx multigene family in S. cerevisiae is discussed. PMID:20562106

Teste, Marie-Ange; François, Jean Marie; Parrou, Jean-Luc

2010-08-27

10

The lactate-proton symport of Saccharomyces cerevisiae is encoded by JEN1  

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A mutant of Saccharomyces cerevisiae deficient in the lactate-proton symport was isolated. Transformation of the mutant with a yeast genomic library allowed the isolation of the gene JEN1 that restored lactate transport. Disruption of JEN1 abolished uptake of lactate. The results indicate that, under the experimental conditions tested, no other monocarboxylate permease is able to efficiently transport lactate in S. cerevisiae.

Casal, Margarida; Paiva, Sandra; Andrade, Raquel P.; Gancedo, Carlos; Lea?o, Ceci?lia

1999-01-01

11

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)

12

RAD6 gene of Saccharomyces cerevisiae encodes a protein containing a tract of 13 consecutive aspartates  

International Nuclear Information System (INIS)

The RAD6 gene of Saccharomyces cerevisiae is required for postreplication repair of UV-damaged DNA, for induced mutagenesis, and for sporulation. The authors have mapped the transcripts and determined the nucleotide sequence of the cloned RAD6 gene. The RAD6 gene encodes two transcripts of 0.98 and 0.86 kilobases which differ only in their 3' termini. The transcribed region contains an open reading frame of 516 nucleotides. The rad6-1 and rad6-3 mutant alleles, which the authors have cloned and sequenced, introduce amber and ochre nonsense mutations, respectively into the open reading frame, proving that it encodes the RAD6 protein. The RAD6 protein predicted by the nucleotide sequence is 172 amino acids long, has a molecular weight of 19,704, and contains 23.3% acidic and 11.6% basic residues. Its most striking feature is the highly acidic carboxyl terminus: 20 of the 23 terminal amino acids are acidic, including 13 consecutive aspartates. RAD6 protein thus resembles high mobility group proteins HMG-1 and HMG-2, which each contain a carboxyl-proximal tract of acidic amino acids. 48 references, 6 figures

13

The Saccharomyces cerevisiae ICL2 Gene Encodes a Mitochondrial 2-Methylisocitrate Lyase Involved in Propionyl-Coenzyme A Metabolism:  

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The Saccharomyces cerevisiae ICL1 gene encodes isocitrate lyase, an essential enzyme for growth on ethanol and acetate. Previous studies have demonstrated that the highly homologous ICL2 gene (YPR006c) is transcribed during the growth of wild-type cells on ethanol. However, even when multiple copies are introduced, ICL2 cannot complement the growth defect of icl1 null mutants. It has therefore been suggested that ICL2 encodes a nonsense mRNA or nonfunctional protein. In the methylcitrate cycl...

Luttik, M. A.; Kotter, P.; Salomons, F. A.; Klei, I. J.; Dijken, J. P.; Pronk, J. T.

2000-01-01

14

Characterization of a New Multigene Family Encoding Isomaltases in the Yeast Saccharomyces cerevisiae, the IMA Family*  

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It has been known for a long time that the yeast Saccharomyces cerevisiae can assimilate ?-methylglucopyranoside and isomaltose. We here report the identification of 5 genes (YGR287c, YIL172c, YJL216c, YJL221c and YOL157c), which, similar to the SUCx, MALx, or HXTx multigene families, are located in the subtelomeric regions of different chromosomes. They share high nucleotide sequence identities between themselves (66–100%) and with the MALx2 genes (63–74%). Comparison of their amino aci...

Teste, Marie-ange; Franc?ois, Jean Marie; Parrou, Jean-luc

2010-01-01

15

The Maltose Permease Encoded by the Mal61 Gene of Saccharomyces Cerevisiae Exhibits Both Sequence and Structural Homology to Other Sugar Transporters  

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The MAL61 gene of Saccharomyces cerevisiae encodes maltose permease, a protein required for the transport of maltose across the plasma membrane. Here we report the nucleotide sequence of the cloned MAL61 gene. A single 1842 bp open reading frame is present within this region encoding the 614 residue putative MAL61 protein. Hydropathy analysis suggests that the secondary structure consists of two blocks of six transmembrane domains separated by an approximately 71 residue intracellular region....

Cheng, Q.; Michels, C. A.

1989-01-01

16

LIPID PHOSPHATE PHOSPHATASES FROM SACCHAROMYCES CEREVISIAE  

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DPP1-encoded and LPP1-encoded lipid phosphate phosphatases are integral membrane proteins in the yeast Saccharomyces cerevisiae. They catalyze the Mg2+-independent dephosphorylation of bioactive lipid phosphate molecules such as diacylglycerol pyrophosphate and phosphatidate. These enzymes possess a three-domain lipid phosphatase motif that is localized to the hydrophilic surface of the membrane. The lipid phosphate phosphatase activities of DPP1-encoded and LPP1-encoded enzymes are measured ...

Carman, George M.; Wu, Wen-i

2007-01-01

17

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

Science.gov (United States)

...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...

2010-04-01

18

A cell cycle-responsive transcriptional control element and a negative control element in the gene encoding DNA polymerase alpha in Saccharomyces cerevisiae.  

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Transcription of the POL1 gene of Saccharomyces cerevisiae, which encodes DNA polymerase alpha, the DNA polymerase required for the initiation of DNA replication, has previously been shown to be cell cycle regulated. To understand how the POL1 gene senses cell cycle position, we have investigated the cis-acting elements that respond to the factors that govern cell cycle progression. In this report we demonstrate that a region of 54 nucleotides containing the repeated element ACGCGT, which con...

Gordon, C. B.; Campbell, J. L.

1991-01-01

19

GUP1 and its close homologue GUP2, encoding multi-membrane-spanning proteins involved in active glycerol uptake in Saccharomyces cerevisiae  

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Many yeast species can utilise glycerol, both as sole carbon source and as an osmolyte. In Saccharomyces cerevisiae, physiological studies have previously shown the presence of an active uptake system driven by electrogenic proton symport. We have used transposon mutagenesis to isolate mutants affected in the transport of glycerol into the cell. Here we present the identification of YGL084c, encoding a multi-membrane-spanning protein, as being essential for proton symport of glycerol into Sac...

Holst, Bjørn; Lunde, Christina; Lages, Fernanda; Oliveira, Rui Pedro Soares; Lucas, Ca?ndida; Kielland-brandt, Morten

2000-01-01

20

SSN genes that affect transcriptional repression in Saccharomyces cerevisiae encode SIN4, ROX3, and SRB proteins associated with RNA polymerase II.  

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The RNA polymerase II of Saccharomyces cerevisiae exists in holoenzyme forms containing a complex, known as the mediator, associated with the carboxyl-terminal domain. The mediator includes several SRB proteins and is required for transcriptional activation. Previous work showed that a cyclin-dependent kinase-cyclin pair encoded by SSN3 and SSN8, two members of the SSN suppressor family, are identical to two SRB proteins in the mediator. Here we have identified the remaining SSN genes by clon...

Song, W.; Treich, I.; Qian, N.; Kuchin, S.; Carlson, M.

1996-01-01

 
 
 
 
21

Overexpression of the Saccharomyces cerevisiae Mannosylphosphodolichol Synthase-Encoding Gene in Trichoderma reesei Results in an Increased Level of Protein Secretion and Abnormal Cell Ultrastructure  

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Production of extracellular proteins plays an important role in the physiology of Trichoderma reesei and has potential industrial application. To improve the efficiency of protein secretion, we overexpressed in T. reesei the DPM1 gene of Saccharomyces cerevisiae, encoding mannosylphosphodolichol (MPD) synthase, under homologous, constitutively acting expression signals. Four stable transformants, each with different copy numbers of tandemly integrated DPM1, exhibited roughly double the activi...

Kruszewska, Joanna S.; Butterweck, Arno H.; Kurza?tkowski, Wies?aw; Migdalski, Andrzej; Kubicek, Christian P.; Palamarczyk, Graz?yna

1999-01-01

22

YET1, YET2 and YET3 of Saccharomyces cerevisiae Encode BAP31 Homologs with Partially Overlapping Functions  

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Full Text Available BAP31 is a polytopic integral membrane protein of the endoplasmic reticulum in mammalian cells. It has been shown to participate in various cellular functions such as protein transport and apoptosis. Saccharomyces cerevisiae genome contains three open reading frames YKL065C, YMR040W and YDL072C, which encode BAP31 homologs. We named these YET1 (for Yeast ER Transmembrane protein, YET2 and YET3, respectively. Similar to mammalian BAP31, Yet1p was shown to be an integral membrane protein localized to the endoplasmic reticulum. YET genes were not essential for viability, but disruption of YET1 increased and YET3 decreased the cell growth in liquid cultures. In the yet1? yet3? and yet2? yet3? double disruptant cells the growth was restored to the level observed in the wild type cells. The results suggest that Yet proteins have partially specialized, but overlapping functions. Furthermore, yet3? cells showed a defect in invertase secretion. The possible role of the yeast BAP31 homologs in the ER export is discussed.

Jaana H. Toikkanen

2006-01-01

23

Characterization of RPR1, an essential gene encoding the RNA component of Saccharomyces cerevisiae nuclear RNase P.  

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RNA components have been identified in preparations of RNase P from a number of eucaryotic sources, but final proof that these RNAs are true RNase P subunits has been elusive because the eucaryotic RNAs, unlike the procaryotic RNase P ribozymes, have not been shown to have catalytic activity in the absence of protein. We previously identified such an RNA component in Saccharomyces cerevisiae nuclear RNase P preparations and have now characterized the corresponding, chromosomal gene, called RP...

Lee, J. Y.; Rohlman, C. E.; Molony, L. A.; Engelke, D. R.

1991-01-01

24

The two gene pairs encoding H2A and H2B play different roles in the Saccharomyces cerevisiae life cycle.  

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We have isolated Saccharomyces cerevisiae mutants bearing deletions of one or the other of the two divergently transcribed gene pairs encoding H2A and H2B. The deletions produced diverse effects on the yeast life cycle. Deletion of TRT1, one of the H2A-H2B gene pair sets, affected mitotic growth, sporulation, spore germination, the heat shock response, and exit from the stationary phase; deletion of TRT2, the other H2A-H2B gene pair set, had negligible effects on these same processes. Using a...

Norris, D.; Osley, M. A.

1987-01-01

25

Mutation of the gene encoding protein kinase C 1 stimulates mitotic recombination in Saccharomyces cerevisiae.  

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We have isolated a recessive allele of the yeast protein kinase C gene (PKC1) which promotes an elevated rate of mitotic recombination and confers a temperature-sensitive growth defect. The rate of recombination was increased between genes in direct repeat and at a series of heteroalleles and was dependent upon the RAD52 gene product. The mutant pkc1 allele was sequenced and found to encode a single amino acid change within the catalytic domain. Osmotic stabilizing agents rescued the temperat...

Huang, K. N.; Symington, L. S.

1994-01-01

26

GUP1 of Saccharomyces cerevisiae Encodes an O-Acyltransferase Involved in Remodeling of the GPI Anchor  

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The anchors of mature glycosylphosphatidylinositol (GPI)-anchored proteins of Saccharomyces cerevisiae contain either ceramide or diacylglycerol with a C26:0 fatty acid in the sn2 position. The primary GPI lipid added to newly synthesized proteins in the ER consists of diacylglycerol with conventional C16 and C18 fatty acids. Here we show that GUP1 is essential for the synthesis of the C26:0-containing diacylglycerol anchors. Gup1p is an ER membrane protein with multiple membran...

Bosson, Re?gine; Jaquenoud, Malika; Conzelmann, Andreas

2006-01-01

27

Expression of the Saccharomyces cerevisiae MPR1 gene encoding N-acetyltransferase in Zygosaccharomyces rouxii confers resistance to L-azetidine-2-carboxylate.  

Science.gov (United States)

The osmotolerant yeast Zygosaccharomyces rouxii is sensitive to the toxic L-proline analogue, L-azetidine-2-carboxylate (AZC). The possibility of use of the Saccharomyces cerevisiae MPR1 gene (ScMPR1) encoding the AZC-detoxifying enzyme as a dominant selection marker in Z. rouxii was examined. The heterologous expression of ScMPR1 in two Z. rouxii strains resulted in AZC-resistant colonies, but that of ScMPR1 as a dominant marker gene in vectors was affected by a high frequency of spontaneously resistant colonies. The same was found for an AZC-sensitive S. cerevisiae strain in which the ScMPR1 was expressed. In both yeasts, ScMPR1 can be used only as an auxiliary marker gene. PMID:17004651

Pribylová, L; Sychrová, H

2006-01-01

28

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

Science.gov (United States)

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

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

2008-03-28

29

Cloning of the sdsA gene encoding solanesyl diphosphate synthase from Rhodobacter capsulatus and its functional expression in Escherichia coli and Saccharomyces cerevisiae.  

Science.gov (United States)

Different organisms produce different species of isoprenoid quinones, each with its own distinctive length. These differences in length are commonly exploited in microbial classification. The side chain length of quinone is determined by the nature of the polyprenyl diphosphate synthase that catalyzes the reaction. To determine if the side chain length of ubiquinone (UQ) has any distinct role to play in the metabolism of the cells in which it is found, we cloned the solanesyl diphosphate synthase gene (sdsA) from Rhodobacter capsulatus SB1003 and expressed it in Escherichia coli and Saccharomyces cerevisiae. Sequence analysis revealed that the sdsA gene encodes a 325-amino-acid protein which has similarity (27 to 40%) with other prenyl diphosphate synthases. Expression of the sdsA gene complemented a defect in the octaprenyl diphosphate synthase gene of E. coli and the nonrespiratory phenotype resulting from a defect in the hexaprenyl diphosphate synthase gene of S. cerevisiae. Both E. coli and S. cerevisiae expressing the sdsA gene mainly produced solanesyl diphosphate, which resulted in the synthesis of UQ-9 without any noticeable effect on the growth of the cells. Thus, it appears that UQ-9 can replace the function of UQ-8 in E. coli and UQ-6 in S. cerevisiae. Taken together with previous results, the results described here imply that the side chain length of UQ is not a critical factor for the survival of microorganisms. PMID:9324242

Okada, K; Kamiya, Y; Zhu, X; Suzuki, K; Tanaka, K; Nakagawa, T; Matsuda, H; Kawamukai, M

1997-10-01

30

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

Science.gov (United States)

... 2010-04-01 false Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems. 866.5785...Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S. cerevisiae ) antibody (ASCA) test...

2010-04-01

31

Genetic Variation of the Repeated Mal Loci in Natural Populations of Saccharomyces Cerevisiae and Saccharomyces Paradoxus  

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In Saccharomyces cerevisiae, the gene functions required to ferment the disaccharide maltose are encoded by the MAL loci. Any one of five highly sequence homologous MAL loci identified in various S. cerevisiae strains (called MAL1, 2, 3, 4 and 6) is sufficient to ferment maltose. Each is a complex of three genes encoding maltose permease, maltase and a transcription activator. This family of loci maps to telomere-linked positions on different chromosomes and most natural strains contain more ...

Naumov, G. I.; Naumova, E. S.; Michels, C. A.

1994-01-01

32

Fungal genomics beyond Saccharomyces cerevisiae?  

DEFF Research Database (Denmark)

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 developments in the past year demonstrate that we have only just started to exploit this potential.

Hofmann, Gerald; Mcintyre, Mhairi

2003-01-01

33

Genetic Characterization of Pathogenic Saccharomyces Cerevisiae Isolates  

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Saccharomyces cerevisiae isolates from human patients have been genetically analyzed. Some of the characteristics of these isolates are very different from laboratory and industrial strains of S. cerevisiae and, for this reason, stringent genetic tests have been used to confirm their identity as S. cerevisiae. Most of these clinical isolates are able to grow at 42°, a temperature that completely inhibits the growth of most other S. cerevisiae strains. This property can be considered a virule...

Mccusker, J. H.; Clemons, K. V.; Stevens, D. A.; Davis, R. W.

1994-01-01

34

Purification and characterization of C1, the catalytic subunit of Saccharomyces cerevisiae cAMP-dependent protein kinase encoded by TPK1.  

Science.gov (United States)

In the yeast Saccharomyces cerevisiae, three genes TPK1, TPK2, and TPK3 encode catalytic subunits of cAMP-dependent protein kinase. We have purified and characterized the catalytic subunit, C1, encoded by the TPK1 gene. In order to purify C1 completely free of C2 and C3, a strain was constructed that contained only the TPK1 gene and genetic disruptions of the other two TPK genes. The cellular level of C1 was increased by expressing the genes for C1 (TPK1) and yeast regulatory subunit (BCY1) on multiple copy plasmids within this strain. Purification was accomplished by a two-column procedure in which holoenzyme was chromatographed on Sephacryl-200, then bound to an anti-regulatory subunit immunoaffinity column. Pure C1 was released from the antibody column by addition of cAMP. The protein migrated on a sodium dodecyl sulfate-polyacrylamide gel with an Mr of 52,000. Kinetic analysis showed that the apparent Km for ATP and Leu-Arg-Arg-Ala-Ser-Leu-Gly was 33 and 101 microM, respectively. The kcat was determined to be 640 min-1. The protein weakly autophosphorylated, incorporating less than 0.1 mol of phosphate/mol of catalytic subunit. NH2-terminal sequencing revealed that the protein was blocked. PMID:3288629

Zoller, M J; Kuret, J; Cameron, S; Levin, L; Johnson, K E

1988-07-01

35

Overexpression of the Saccharomyces cerevisiae mannosylphosphodolichol synthase-encoding gene in Trichoderma reesei results in an increased level of protein secretion and abnormal cell ultrastructure.  

Science.gov (United States)

Production of extracellular proteins plays an important role in the physiology of Trichoderma reesei and has potential industrial application. To improve the efficiency of protein secretion, we overexpressed in T. reesei the DPM1 gene of Saccharomyces cerevisiae, encoding mannosylphosphodolichol (MPD) synthase, under homologous, constitutively acting expression signals. Four stable transformants, each with different copy numbers of tandemly integrated DPM1, exhibited roughly double the activity of MPD synthase in the respective endoplasmic reticulum membrane fraction. On a dry-weight basis, they secreted up to sevenfold-higher concentrations of extracellular proteins during growth on lactose, a carbon source promoting formation of cellulases. Northern blot analysis showed that the relative level of the transcript of cbh1, which encodes the major cellulase (cellobiohydrolase I [CBH I]), did not increase in the transformants. On the other hand, the amount of secreted CBH I and, in all but one of the transformants, intracellular CBH I was elevated. Our results suggest that posttranscriptional processes are responsible for the increase in CBH I production. The carbohydrate contents of the extracellular proteins were comparable in the wild type and in the transformants, and no hyperglycosylation was detected. Electron microscopy of the DPM1-amplified strains revealed amorphous structure of the cell wall and over three times as many mitochondria as in the control. Our data indicate that molecular manipulation of glycan biosynthesis in Trichoderma can result in improved protein secretion. PMID:10347017

Kruszewska, J S; Butterweck, A H; Kurzatkowski, W; Migdalski, A; Kubicek, C P; Palamarczyk, G

1999-06-01

36

YET1, YET2 and YET3 of Saccharomyces cerevisiae Encode BAP31 Homologs with Partially Overlapping Functions  

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BAP31 is a polytopic integral membrane protein of the endoplasmic reticulum in mammalian cells. It has been shown to participate in various cellular functions such as protein transport and apoptosis. Saccharomyces cerevisiae genome contains three open reading frames YKL065C, YMR040W and YDL072C, which encode BAP31 homologs. We named these YET1 (for Yeast ER Transmembrane protein), YET2 and YET3, respectively. Similar to mammalian BAP31, Yet1p w...

Toikkanen, Jaana H.; Netta Fatal; Pekka Hilden; Marja Makarow; Esa Kuismanen

2006-01-01

37

Expression of Saccharomyces cerevisiae inorganic pyrophosphatase in Escherichia coli.  

Science.gov (United States)

A segment of DNA encoding Saccharomyces cerevisiae inorganic pyrophosphatase (ppa gene) was amplified by the polymerase chain reaction. The pSCH1 and pSCB6 plasmids containing the ppa gene were obtained. Transformation of the E. coli BL21 strain with the resulting recombinant plasmids and selection of clones having extremely high expression of inorganic pyrophosphatase (PPase) were carried out. Superproduction of recombinant S. cerevisiae PPase up to 50% of the total bacterial protein was achieved. The enzyme was readily obtained and purified to homogeneity with the use of a simple purification technique. This work is the first description of S. cerevisiae PPase superproducer creation. PMID:8224193

Kurilova, S A; Vorobjeva, N N; Nazarova, T I; Avaeva, S M

1993-11-01

38

Lactose fermentation by recombinant Saccharomyces cerevisiae strains  

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The development of Saccharomyces cerevisiae strains with the ability to ferment lactose has a high biotechnological interest, particularly for cheese whey bioremediation processes with simultaneous bio-ethanol production. We have developed a flocculent S. cerevisiae strain that efficiently ferments lactose to ethanol, using a combination of genetic engineering and evolutionary engineering approaches. This strain fermented efficiently and nearly completely (residual lactose < 3 ...

Guimara?es, Pedro M. R.; Teixeira, J. A.; Domingues, Luci?lia

2008-01-01

39

Progress in Metabolic Engineering of Saccharomyces cerevisiae  

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Summary: The traditional use of the yeast Saccharomyces cerevisiae in alcoholic fermentation has, over time, resulted in substantial accumulated knowledge concerning genetics, physiology, and biochemistry as well as genetic engineering and fermentation technologies. S. cerevisiae has become a platform organism for developing metabolic engineering strategies, methods, and tools. The current review discusses the relevance of several engineering strategies, such as rational and inverse metabolic...

Nevoigt, Elke

2008-01-01

40

Thiamine transport in Saccharomyces cerevisiae protoplasts.  

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Thiamine was found to be accumulated in protoplasts of Saccharomyces cerevisiae in the same manner as in intact cells, suggesting that a soluble thiamine-binding protein in periplasm may not be an essential component of the thiamine transport system of S. cerevisiae. It was also found that thiamine pyrophosphate cannot be taken up by yeast protoplasts.

Nishimura, H.; Sempuku, K.; Iwashima, A.

1982-01-01

 
 
 
 
41

Fatal Saccharomyces Cerevisiae Aortic Graft Infection  

Science.gov (United States)

Saccharomyces cerevisiae is a yeast commonly used in baking and a frequent colonizer of human mucosal surfaces. It is considered relatively nonpathogenic in immunocompetent adults. We present a case of S. cerevisiae fungemia and aortic graft infection in an immunocompetent adult. This is the first reported case of S. cerevisiue fungemia where the identity of the pathogen was confirmed by rRNA sequencing.

Meyer, Michael (Technical Monitor); Smith, Davey; Metzgar, David; Wills, Christopher; Fierer, Joshua

2002-01-01

42

Transcriptional Regulatory Networks in Saccharomyces cerevisiae  

Science.gov (United States)

We have determined how most of the transcriptional regulators encoded in the eukaryote Saccharomyces cerevisiae associate with genes across the genome in living cells. Just as maps of metabolic networks describe the potential pathways that may be used by a cell to accomplish metabolic processes, this network of regulator-gene interactions describes potential pathways yeast cells can use to regulate global gene expression programs. We use this information to identify network motifs, the simplest units of network architecture, and demonstrate that an automated process can use motifs to assemble a transcriptional regulatory network structure. Our results reveal that eukaryotic cellular functions are highly connected through networks of transcriptional regulators that regulate other transcriptional regulators.

Lee, Tong Ihn; Rinaldi, Nicola J.; Robert, François; Odom, Duncan T.; Bar-Joseph, Ziv; Gerber, Georg K.; Hannett, Nancy M.; Harbison, Christopher T.; Thompson, Craig M.; Simon, Itamar; Zeitlinger, Julia; Jennings, Ezra G.; Murray, Heather L.; Gordon, D. Benjamin; Ren, Bing; Wyrick, John J.; Tagne, Jean-Bosco; Volkert, Thomas L.; Fraenkel, Ernest; Gifford, David K.; Young, Richard A.

2002-10-01

43

Filamentous growth in Saccharomyces cerevisiae / Filamentação em Saccharomyces cerevisiae  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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.

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

2004-09-01

44

The GEF1 gene of Saccharomyces cerevisiae encodes an integral membrane protein; mutations in which have effects on respiration and iron-limited growth.  

Science.gov (United States)

We have isolated a new class of respiration-defective, i.e petite, mutants of the yeast Saccharomyces cerevisiae. Mutations in the GEF1 gene cause cells to grow slowly on rich media containing carbon sources utilized by respiration. This phenotype is suppressed by adding high concentrations of iron to the growth medium. Gef1- mutants also fail to grow on a fermentable carbon source, glucose, when iron is reduced to low concentrations in the medium, suggesting that the GEF1 gene is required for efficient metabolism of iron during growth on fermentable as well as respired carbon sources. However, activity of the iron uptake system appears to be unaffected in gef1- mutants. Fe(II) transporter activity and regulation is normal in gef1- mutants. Fe(III) reductase induction during iron-limited growth is disrupted, but this appears to be a secondary effect of growth rate alterations. The wild-type GEF1 gene was cloned and sequenced; it encodes a protein of 779 amino acids, 13 possible transmembrane domains, and significant similarity to chloride channel proteins from fish and mammals, suggesting that GEF1 encodes an integral membrane protein. A gef1- deletion mutation generated in vitro and introduced into wild-type haploid strains by gene transplacement was not lethal. Oxygen consumption by intact gef1- cells and by mitochondrial fractions isolated from gef1- mutants was reduced 25-50% relative to wild type, indicating that mitochondrial function is defective in these mutants. We suggest that GEF1 encodes a transport protein that is involved in intracellular iron metabolism. PMID:7505388

Greene, J R; Brown, N H; DiDomenico, B J; Kaplan, J; Eide, D J

1993-12-01

45

A cell cycle-responsive transcriptional control element and a negative control element in the gene encoding DNA polymerase alpha in Saccharomyces cerevisiae.  

Science.gov (United States)

Transcription of the POL1 gene of Saccharomyces cerevisiae, which encodes DNA polymerase alpha, the DNA polymerase required for the initiation of DNA replication, has previously been shown to be cell cycle regulated. To understand how the POL1 gene senses cell cycle position, we have investigated the cis-acting elements that respond to the factors that govern cell cycle progression. In this report we demonstrate that a region of 54 nucleotides containing the repeated element ACGCGT, which conforms to an Mlu I restriction endonuclease recognition site, contains all information necessary for transcriptional activation and cell cycle responsiveness. Although oligonucleotides lacking either one or both of the repeated Mlu I sites can function as an upstream activating sequence, the presence of at least one Mlu I site stimulates expression and, moreover, is absolutely essential for cell cycle regulation. A synthetic oligonucleotide corresponding to a 19-base-pair sequence in the POL1 promoter containing one Mlu I site can function as an autonomous cell cycle-responsive upstream element (upstream activation sequence) with temporal regulation indistinguishable from that previously described for the POL1 gene. Thus, the Mlu I site is an essential part of a cis-acting element responsible for the observed periodic activation. This sequence differs from previously defined cell cycle-responsive transcriptional control elements in the yeast HO endonuclease and histone genes. We also present evidence for a negative regulatory element in the 5' flanking region of the Mlu I upstream activation sequence. Images PMID:2068085

Gordon, C B; Campbell, J L

1991-01-01

46

SCUD: Saccharomyces Cerevisiae Ubiquitination Database  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Ubiquitination is an important post-translational modification involved in diverse biological processes. Therefore, genomewide representation of the ubiquitination system for a species is important. Description SCUD is a web-based database for the ubiquitination system in Saccharomyces cerevisiae (Baker's yeast. We first searched for all the known enzymes involved in the ubiquitination process in yeast, including E1, E2, E3, and deubiquitination enzymes. Then, ubiquitinated substrates were collected by literature search. Especially, E3 and deubiquitination enzymes are classified into classes and subclasses by their shared domains and unique functions. As a result, 42 different E3 enzymes were grouped into corresponding classes and subclasses, and 940 ubiquitinated substrates including mutant substrates were identified. All the enzyme and substrate information are interconnected by hyperlinks, which makes it easy to view the enzyme-specific ubiquitination information. Conclusion This database aims to represent a comprehensive yeast ubiquitination system, and is easily expandable with the further experimental data. We expect that this database will be useful for the research on the ubiquitination systems of other higher organisms. SCUD is accessible at http://scud.kaist.ac.kr

Jung Jin Woo

2008-09-01

47

The Saccharomyces cerevisiae FKS1 (ETG1) gene encodes an integral membrane protein which is a subunit of 1,3-beta-D-glucan synthase.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Saccharomyces cerevisiae, mutations in FKS1 confer hypersensitivity to the immunosuppressants FK506 and cyclosporin A, while mutations in ETG1 confer resistance to the cell-wall-active echinocandins (inhibitors of 1,3-beta-D-glucan synthase) and, in some cases, concomitant hypersensitivity to the chitin synthase inhibitor nikkomycin Z. The FKS1 and ETG1 genes were cloned by complementation of these phenotypes and were found to be identical. Disruption of the gene results in (i) a pronounce...

Douglas, C. M.; Foor, F.; Marrinan, J. A.; Morin, N.; Nielsen, J. B.; Dahl, A. M.; Mazur, P.; Baginsky, W.; Li, W.; El-sherbeini, M.

1994-01-01

48

Overproduction of Geranylgeraniol by Metabolically Engineered Saccharomyces cerevisiae?  

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(E, E, E)-Geranylgeraniol (GGOH) is a valuable starting material for perfumes and pharmaceutical products. In the yeast Saccharomyces cerevisiae, GGOH is synthesized from the end products of the mevalonate pathway through the sequential reactions of farnesyl diphosphate synthetase (encoded by the ERG20 gene), geranylgeranyl diphosphate synthase (the BTS1 gene), and some endogenous phosphatases. We demonstrated that overexpression of the diacylglycerol diphosphate phosphatase (DPP1) gene could...

Tokuhiro, Kenro; Muramatsu, Masayoshi; Ohto, Chikara; Kawaguchi, Toshiya; Obata, Shusei; Muramoto, Nobuhiko; Hirai, Masana; Takahashi, Haruo; Kondo, Akihiko; Sakuradani, Eiji; Shimizu, Sakayu

2009-01-01

49

Metabolic engineering of glycerol production in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2002-01-01

50

Dominant effects of tubulin overexpression in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The consequences of altering the levels of alpha- and beta-tubulin in Saccharomyces cerevisiae were examined by constructing fusions of the structural genes encoding the tubulins to strong galactose-inducible promoters. Overexpression of beta-tubulin (TUB2) was lethal: cells arrested in the G2 stage of the cell cycle exhibited an increased frequency of chromosome loss, were devoid of microtubules, and accumulated beta-tubulin in a novel structure. Overexpression of the major alpha-tubulin gen...

Burke, D.; Gasdaska, P.; Hartwell, L.

1989-01-01

51

A Sequence-Specific Interaction between the Saccharomyces cerevisiae rRNA Gene Repeats and a Locus Encoding an RNA Polymerase I Subunit Affects Ribosomal DNA Stability.  

Science.gov (United States)

The spatial organization of eukaryotic genomes is linked to their functions. However, how individual features of the global spatial structure contribute to nuclear function remains largely unknown. We previously identified a high-frequency interchromosomal interaction within the Saccharomyces cerevisiae genome that occurs between the intergenic spacer of the ribosomal DNA (rDNA) repeats and the intergenic sequence between the locus encoding the second largest RNA polymerase I subunit and a lysine tRNA gene [i.e., RPA135-tK(CUU)P]. Here, we used quantitative chromosome conformation capture in combination with replacement mapping to identify a 75-bp sequence within the RPA135-tK(CUU)P intergenic region that is involved in the interaction. We demonstrate that the RPA135-IGS1 interaction is dependent on the rDNA copy number and the Msn2 protein. Surprisingly, we found that the interaction does not govern RPA135 transcription. Instead, replacement of a 605-bp region within the RPA135-tK(CUU)P intergenic region results in a reduction in the RPA135-IGS1 interaction level and fluctuations in rDNA copy number. We conclude that the chromosomal interaction that occurs between the RPA135-tK(CUU)P and rDNA IGS1 loci stabilizes rDNA repeat number and contributes to the maintenance of nucleolar stability. Our results provide evidence that the DNA loci involved in chromosomal interactions are composite elements, sections of which function in stabilizing the interaction or mediating a functional outcome. PMID:25421713

Cahyani, Inswasti; Cridge, Andrew G; Engelke, David R; Ganley, Austen R D; O'Sullivan, Justin M

2015-02-01

52

Effects of pentamidine isethionate on Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We used Saccharomyces cerevisiae as a model system in which to examine the mechanism of action of the anti-Pneumocystis drug pentamidine. Pentamidine at low concentrations inhibited S. cerevisiae growth on nonfermentable carbon sources (50% inhibitory concentration [IC50] of 1.25 micrograms/ml in glycerol). Pentamidine inhibited growth on fermentable energy sources only at much higher concentrations (IC50 of 250 micrograms/ml in glucose). Inhibition at low pentamidine concentrations in glycer...

Ludewig, G.; Williams, J. M.; Li, Y.; Staben, C.

1994-01-01

53

Regulation of thiamine biosynthesis in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A pho6 mutant of Saccharomyces cerevisiae, lacking a regulatory gene for the synthesis of periplasmic thiamine-repressible acid phosphatase activity, was found to be auxotrophic for thiamine. The activities of four enzymes involved in the synthesis of thiamine monophosphate were hardly detectable in the crude extract from the pho6 mutant. On the other hand, the activities of these enzymes and thiamine-repressible acid phosphatase in a wild-type strain of S. cerevisiae, H42, decreased with the...

Kawasaki, Y.; Nosaka, K.; Kaneko, Y.; Nishimura, H.; Iwashima, A.

1990-01-01

54

Global regulation of mitochondrial biogenesis in Saccharomyces cerevisiae: ABF1 and CPF1 play opposite roles in regulating expression of the QCR8 gene, which encodes subunit VIII of the mitochondrial ubiquinol-cytochrome c oxidoreductase.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The multifunctional DNA-binding proteins ABF1 and CPF1 bind in a mutually exclusive manner to the promoter region of the QCR8 gene, which encodes 11-kDa subunit VIII of the Saccharomyces cerevisiae mitochondrial ubiquinol-cytochrome c oxidoreductase (QCR). We investigated the roles that the two factors play in transcriptional regulation of this gene. To this end, the overlapping binding sites for ABF1 and CPF1 were mutated and placed in the chromosomal context of the QCR8 promoter. The effect...

Winde, J. H.; Grivell, L. A.

1992-01-01

55

Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions  

Science.gov (United States)

Experimental work on ultrafiltration is presented to illustrate the practical and theoretical principles of this separation technique. The laboratory exercise comprises experiments with pure water and with aqueous "Saccharomyces cerevisiae" (from commercial Baker's yeast) suspensions. With this work students detect the characteristic phenomena…

Silva, Carlos M.; Neves, Patricia S.; Da Silva, Francisco A.; Xavier, Ana M. R. B.; Eusebio, M. F. J.

2008-01-01

56

Biosynthesis of Natural Flavanones in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A four-step flavanone biosynthetic pathway was constructed and introduced into Saccharomyces cerevisiae. The recombinant yeast strain was fed with phenylpropanoid acids and produced the flavanones naringenin and pinocembrin 62 and 22 times more efficiently compared to previously reported recombinant prokaryotic strains. Microbial biosynthesis of the flavanone eriodictyol was also achieved.

Yan, Yajun; Kohli, Abhijeet; Koffas, Mattheos A. G.

2005-01-01

57

CAT8, a new zinc cluster-encoding gene necessary for derepression of gluconeogenic enzymes in the yeast Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The expression of gluconeogenic fructose-1,6-bisphosphatase (encoded by the FBP1 gene) depends on the carbon source. Analysis of the FBP1 promoter revealed two upstream activating elements, UAS1FBP1 and UAS2FBP1, which confer carbon source-dependent regulation on a heterologous reporter gene. On glucose media neither element was activated, whereas after transfer to ethanol a 100-fold derepression was observed. This gene activation depended on the previously identified derepression genes CAT1 ...

Hedges, D.; Proft, M.; Entian, K. D.

1995-01-01

58

Epistatic interactions of deletion mutants in the genes encoding the F1-ATPase in yeast Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The F1-ATPase is a multimeric enzyme (alpha3 beta3 gamma delta epsilon) primarily responsible for the synthesis of ATP under aerobic conditions. The entire coding region of each of the genes was deleted separately in yeast, providing five null mutant strains. Strains with a deletion in the genes encoding alpha-, beta-, gamma- or delta-subunits were unable to grow, while the strain with a null mutation in epsilon was able to grow slowly on medium containing glycerol as the carbon source. In ad...

Lai-zhang, J.; Xiao, Y.; Mueller, D. M.

1999-01-01

59

Mechanism of Uranium mineralization by Saccharomyces cerevisiae  

Science.gov (United States)

We examined mechanism of the uranium mineralization by the yeast (Saccharomyces cerevisiae, X-2180-1B). Uptake experiments of U by S. cerevisiae were carried out for 4.2x10-4 M U solutions with their final pHs between 3 and 5. Concentrations of U and P were measured at the predetermined intervals. After 96 hours of contact time, the U accumulated S. cerevisiae was observed by scanning electron microscope equipped with energy dispersive spectroscopy (SEM-EDS). The Kd, defined by the ratio of U accumulated in S. cerevisiae to that in solution, shows monotone increase with time below pH 4, and reached steady state within 60 hours above pH 4. During U accumulation P was released from S. cerevisiae, while no release of P was observed in the absence of U. SEM-EDS analyses of the U accumulated S. cerevisiae indicated that uranyl phosphate minerals were occurred on the surface of S. cerevisiae at any pH. Thermodynamic calculation indicated that chemical compositions of the solutions at pH above 4 were super-saturated with respect to H-autunite. On the contrary, the chemical compositions of the solutions of pHs below 4 were under-saturated with respect to H-autunite, and were super-saturated at one-order higher concentration of U(VI) or P than observed. These results indicate that U mineralization is metabolism dependent, induced by the release of P from S. cerevisiae. Two different processes are relevant to U mineralization by S. cerevisiae. One is the process in which U reacts in the solution with P released from S. cerevisiae, where the chemical composition in the solution is super-saturated with respect to H-autunite. The other is the process in which U reacts with P on the surface of S. cerevisiae, where H-autunite is occurred by local-saturation condition.

Ohnuki, T.; Ozaki, T.; Yoshida, T.; Kozai, N.; Francis, A. J.; Iefuji, H.

2002-12-01

60

Xylose utilizing recombinant Saccharomyces cerevisiae strains  

Energy Technology Data Exchange (ETDEWEB)

Through metabolic engineering, S. cerevisiae was provided with the necessary enzymes required for xylose utilisation during ethanolic fermentation of xylose-rich lignocellulose raw materials. For xylitol production, S. cerevisiae was provided with the Pichia stipitis XYL1 gene encoding xylose reductase (XR). The in-vivo reduction and the following excretion of xylitol, requires a co-substrate for maintenance and cofactor regeneration. Xylitol yields close to 100% were obtained with the XYL1 containing S. cerevisiae. Introducing P. stipitis XYL1 and XYL2 genes, encoding XR and xylitol dehydrogenase (XDH), respectively, enabled S. cerevisiae to convert xylose to xylulose, via xylitol. During the screening work of P. stipitis XDH gene, another gene encoding a polyol dehydrogenase was isolated and cloned in S. cerevisiae. The gene was identified as a D-arabinitol dehydrogenase gene. In P. stipitis it may function as a redox sink by reducing D-ribulose to D-arabinitol. The metabolism through the pentose phosphate pathway (PPP) was enhanced by over-expressing the native genes TKL1 and TAL1 encoding transketolase and transaldolase, respectively, resulting in improved xylose utilisation. The XR and XDH activities in recombinant S. cerevisiae were produced at different levels by constructing yeast vectors in which the PGK1 and ADHI promoters controlled XYL1 and XYL2. With higher XDH than XR activities, less by-products, in the form of xylitol and glycerol, were formed by the recombinant S. cerevisiae strains. The Thermus thermophilus xylA gene encoding a thermostable xylose isomerase was cloned and expressed in S. cerevisiae. The recombinant xylose isomerase was actively produced and a new functional metabolic pathway was established in S. cerevisiae resulting in ethanol production from xylose. 150 refs, 3 figs, 4 tabs

Walfridsson, M.

1996-04-01

 
 
 
 
61

Comet assay on Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this project is to clarify whether Saccaromyces cerevisiae (bakers yeast) can be used as a model for Mytilus edulis (blue mussel) in association with investigation of DNA damage. S. cerevisiae was exposed to the herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) in order to examine this. For the purpose of measuring the genotoxic damages the Single Cell Gel Electrophoresis (SCGE) method was used, also known as comet assay. The results were compared with results from a similar exp...

Wennermark, Henrik; Dahl, Rasmus; Kolstrup, Johan; Selmer, Ulrik; Kimer, Anine Svendsen; Axelsen, Lykke Vils

2007-01-01

62

Stationary phase in the yeast Saccharomyces cerevisiae.  

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Growth and proliferation of microorganisms such as the yeast Saccharomyces cerevisiae are controlled in part by the availability of nutrients. When proliferating yeast cells exhaust available nutrients, they enter a stationary phase characterized by cell cycle arrest and specific physiological, biochemical, and morphological changes. These changes include thickening of the cell wall, accumulation of reserve carbohydrates, and acquisition of thermotolerance. Recent characterization of mutant c...

Werner-washburne, M.; Braun, E.; Johnston, G. C.; Singer, R. A.

1993-01-01

63

On Cycles in the Transcription Network of Saccharomyces cerevisiae  

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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 LS...

Berman Piotr; Jeong Jieun

2007-01-01

64

Phosphoenolpyruvate carboxykinase as the sole anaplerotic enzyme in Saccharomyces cerevisiae.  

Science.gov (United States)

Pyruvate carboxylase is the sole anaplerotic enzyme in glucose-grown cultures of wild-type Saccharomyces cerevisiae. Pyruvate carboxylase-negative (Pyc(-)) S. cerevisiae strains cannot grow on glucose unless media are supplemented with C(4) compounds, such as aspartic acid. In several succinate-producing prokaryotes, phosphoenolpyruvate carboxykinase (PEPCK) fulfills this anaplerotic role. However, the S. cerevisiae PEPCK encoded by PCK1 is repressed by glucose and is considered to have a purely decarboxylating and gluconeogenic function. This study investigates whether and under which conditions PEPCK can replace the anaplerotic function of pyruvate carboxylase in S. cerevisiae. Pyc(-) S. cerevisiae strains constitutively overexpressing the PEPCK either from S. cerevisiae or from Actinobacillus succinogenes did not grow on glucose as the sole carbon source. However, evolutionary engineering yielded mutants able to grow on glucose as the sole carbon source at a maximum specific growth rate of ca. 0.14 h(-1), one-half that of the (pyruvate carboxylase-positive) reference strain grown under the same conditions. Growth was dependent on high carbon dioxide concentrations, indicating that the reaction catalyzed by PEPCK operates near thermodynamic equilibrium. Analysis and reverse engineering of two independently evolved strains showed that single point mutations in pyruvate kinase, which competes with PEPCK for phosphoenolpyruvate, were sufficient to enable the use of PEPCK as the sole anaplerotic enzyme. The PEPCK reaction produces one ATP per carboxylation event, whereas the original route through pyruvate kinase and pyruvate carboxylase is ATP neutral. This increased ATP yield may prove crucial for engineering of efficient and low-cost anaerobic production of C(4) dicarboxylic acids in S. cerevisiae. PMID:20581175

Zelle, Rintze M; Trueheart, Josh; Harrison, Jacob C; Pronk, Jack T; van Maris, Antonius J A

2010-08-01

65

Phosphoenolpyruvate Carboxykinase as the Sole Anaplerotic Enzyme in Saccharomyces cerevisiae?  

Science.gov (United States)

Pyruvate carboxylase is the sole anaplerotic enzyme in glucose-grown cultures of wild-type Saccharomyces cerevisiae. Pyruvate carboxylase-negative (Pyc?) S. cerevisiae strains cannot grow on glucose unless media are supplemented with C4 compounds, such as aspartic acid. In several succinate-producing prokaryotes, phosphoenolpyruvate carboxykinase (PEPCK) fulfills this anaplerotic role. However, the S. cerevisiae PEPCK encoded by PCK1 is repressed by glucose and is considered to have a purely decarboxylating and gluconeogenic function. This study investigates whether and under which conditions PEPCK can replace the anaplerotic function of pyruvate carboxylase in S. cerevisiae. Pyc? S. cerevisiae strains constitutively overexpressing the PEPCK either from S. cerevisiae or from Actinobacillus succinogenes did not grow on glucose as the sole carbon source. However, evolutionary engineering yielded mutants able to grow on glucose as the sole carbon source at a maximum specific growth rate of ca. 0.14 h?1, one-half that of the (pyruvate carboxylase-positive) reference strain grown under the same conditions. Growth was dependent on high carbon dioxide concentrations, indicating that the reaction catalyzed by PEPCK operates near thermodynamic equilibrium. Analysis and reverse engineering of two independently evolved strains showed that single point mutations in pyruvate kinase, which competes with PEPCK for phosphoenolpyruvate, were sufficient to enable the use of PEPCK as the sole anaplerotic enzyme. The PEPCK reaction produces one ATP per carboxylation event, whereas the original route through pyruvate kinase and pyruvate carboxylase is ATP neutral. This increased ATP yield may prove crucial for engineering of efficient and low-cost anaerobic production of C4 dicarboxylic acids in S. cerevisiae. PMID:20581175

Zelle, Rintze M.; Trueheart, Josh; Harrison, Jacob C.; Pronk, Jack T.; van Maris, Antonius J. A.

2010-01-01

66

TAP tagging proteins in Saccharomyces Cerevisiae  

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Tandem Affinity Purification (TAP) is a technique based on attaching a tag to the N- or C- terminus of target proteins. The tagged proteins can then be used for studies of protein-protein or protein-DNA interactions. In this study TAP tags of Med7, Tfb3, Spt3, Spt15 and Gal80 were attached to the C-termini in the yeast Saccharomyces cerevisiae by transformation with PCR-generated DNA fragments which integrate into the yeast genome by homologous recombination. The TAP tags will facilitate func...

Roma?n, Lorena Casado

2012-01-01

67

PRODUCTION OF ERGOSTEROL BY SACCHAROMYCES CEREVISIAE  

Directory of Open Access Journals (Sweden)

Full Text Available 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 strain Gyöng cultivation.

Blažena Lavová

2013-02-01

68

Biosorption of americium-241 by Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

The biosorption of radionuclide 241Am from solution by Saccharomyces cerevisiae (S. cerevisiae), and the effects of experimental conditions on the adsorption were investigated. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total 241Am could be removed by S. cerevisiae of 2.1 g/l (dry weight) from 241Am solutions of 17.54-4386.0 ?g/l (2.22 MBq/l-555 MBq/l) with adsorption capacities of 7.45-1880.0 ?g/g biomass (dry weight) (0.94 MBq/g-237.9 MBq/g). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. No significant differences on 241Am adsorption were observed at 10-45 deg C, or in solutions containing Au3+ or Ag+, even 2000 times above 241Am concentration. The relationship between concentrations and adsorption capacities of 241Am indicated the biosorption process should be described by the Freundlich adsorption isotherm. (author)

69

Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae  

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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 fe...

Fay, Justin C.; Benavides, Joseph A.

2005-01-01

70

Adaption of Saccharomyces cerevisiae expressing a heterologous protein  

DEFF Research Database (Denmark)

Production of the heterologous protein, bovine aprotinin, in Saccharomyces cerevisiae was shown to affect the metabolism of the host cell to various extent depending on the strain genotype. Strains with different genotypes, industrial and laboroatory, respectively, were investigated. The maximal specific growth rate of the strains was reduced by 54% and 33%, respectively, upon the introduction of the gene encoding aprotinin. Growing the strains in sequential shake flask cultivations for 250 generations led to an increased maximal specific growth rate and a decrease in the yield of aprotinin as a result of the adaptation. Determination of the level of mRNA encoding aprotinin and the plasmid copy number pointed to different mechanisms responsible for the decline in aprotinin yield in the different strains. (C) 2008 Elsevier B.V. All rights reserved.

Krogh, Astrid MØrkeberg; Beck, Vibe

2008-01-01

71

Expression of VHHs in Saccharomyces cerevisiae.  

Science.gov (United States)

The production of VHHs in microorganisms is relatively straightforward, however the amount of VHH produced per volume unit can vary substantially from hardly detectable to hundreds of milligrams per liter. Expression in Escherichia coli is more commonly used at initial research phase, since production of VHHs for large-scale application in E. coli is for a number of reasons not preferred. Otherwise VHH production in GRAS organisms such as Saccharomyces cerevisiae fits very well with industrial fermentation processes, and in fact the only commercially available VHHs are produced in S. cerevisiae. Immediately after the discovery of heavy chain only antibodies, which are per definition devoid of light chains, it was investigated whether many problems encountered with the production of conventional antibodies in lower eukaryotes were absent during the production of VHHs. Here we provide a protocol for the expression of VHH genes in S. cerevisiae in a fed-batch fermentation process. This protocol is also suitable for the production of multivalent VHHs. PMID:22886258

Gorlani, Andrea; de Haard, Hans; Verrips, Theo

2012-01-01

72

PRIMARY STRUCTURE OF THE P450 LANOSTEROL DEMETHYLASE GENE FROM SACCHAROMYCES CEREVISIAE  

Science.gov (United States)

We have sequenced the structural gene and flanking regions for lanosterol 14oc-demethylase (14DM) from Saccharomyces cerevisiae. n open reading fram of 530 codons encodes a 60.7-kDa protein. hen this gene is disrupted by integrative transformation, the resulting strain requires e...

73

40 CFR 180.1246 - Yeast Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of a...  

Science.gov (United States)

...Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of...Extract Hydrolysate from Saccharomyces cerevisiae: exemption from the requirement of...Extract Hydrolysate from Saccharomyces cerevisiae on all food commodities when...

2010-07-01

74

Modification of mutation frequency in Saccharomyces Cerevisiae  

International Nuclear Information System (INIS)

In a reverse mutation system, using haploid, histidine-requirinq strain of Saccharomyces cerevisiae, the frequency of uv-induced prototrophs increased if the post-irradiation minimal medium was supplemented with limited amounts of histidine. Addition of natural amino acids or RNA bases in the post-irradiation minimal medium, with or without histidine, also increased the uv-induced mutation frequency. Thus, post-irradiation conditions favouring protein and RNA synthesis, are effective in increasing uv-induced mutations in yeast. As compared to uv light, nitrous acid was more effective in inducing reversions in this strain and the frequency increased if the treated cells were plated on minimal medium supplemented with limited amounts of histidine. However, the addition of amino acids or RNA bases decreased the number of revertants. An additional inclusion of histidine reversed the suppressive effect of these metabolites. The mutation induction processes are thus different or differently modifiable in uv and nitrous acid. (author)

75

Phenotypical signs and chemical composition of Saccharomyces cerevisiae – mannoprotein producers  

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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.

Agafia USATII

2012-11-01

76

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)

77

Activation of the Epstein-Barr virus BMRF1 and BZLF1 promoters by ZEBRA in Saccharomyces cerevisiae.  

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ZEBRA has been shown to activate model reporter genes consisting of synthetic oligomerized ZEBRA response elements upstream of a minimal CYC1 promoter fused to beta-galactosidase in the yeast Saccharomyces cerevisiae. Here it is shown that in S. cerevisiae ZEBRA activates transcription of natural Epstein-Barr virus promoters. Two Epstein-Barr virus promoters were shown to be activated by ZEBRA in S. cerevisiae: Zp, the promoter that regulates expression of BZLF1, which encodes ZEBRA; and EAp,...

Countryman, J. K.; Heston, L.; Gradoville, L.; Himmelfarb, H.; Serdy, S.; Miller, G.

1994-01-01

78

Characterization of the PNT1 pentamidine resistance gene of Saccharomyces cerevisiae.  

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The Saccharomyces cerevisiae PNT1 gene was isolated and characterized. When present in high copy number in S. cerevisiae, PNT1 confers resistance to the anti-Pneumocystis carinii drug pentamidine. The PNT1 gene encodes a previously uncharacterized polypeptide of 409 amino acids. The predicted gene product is a very basic (pI 9.9) polypeptide with one potential membrane-associated region. PNT1 is located on chromosome XVR of S. cerevisiae. It is transcribed at a very low level. Overexpression ...

Ludewig, G.; Staben, C.

1994-01-01

79

Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model  

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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.

Serge Feyder

2015-01-01

80

Response of Saccharomyces cerevisiae to cadmium stress  

Energy Technology Data Exchange (ETDEWEB)

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)

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

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

Science.gov (United States)

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 7 mM 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. PMID:25572229

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

2014-12-01

82

Cyclic AMP and Fluconazole Resistance in Saccharomyces cerevisiae  

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Cyclic AMP (cAMP) is involved in the stress response in Saccharomyces cerevisiae. We show that cAMP is required for resistance to fluconazole in S. cerevisiae. In addition, activation of Ras2, a regulator of cAMP generation, results in some protection from fluconazole toxicity in a fashion independent of the efflux transporter Pdr5p.

Kontoyiannis, D. P.; Rupp, Steffen

2000-01-01

83

Expression of the Saccharomyces cerevisiae PIS gene and synthesis of phosphatidylinositol in Escherichia coli.  

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Expression of the Saccharomyces cerevisiae PIS gene encoding phosphatidylinositol synthase in Escherichia coli was achieved by inserting its coding sequence into lacZ on pUC8. The fused gene encoded a phosphatidylinositol synthase whose amino-terminal three amino acids had been replaced by the amino-terminal five amino acids of E. coli beta-galactosidase. E. coli cells bearing this recombinant plasmid produced a significant level of phosphatidylinositol synthase in the presence of a lacZ indu...

Nikawa, J.; Kodaki, T.; Yamashita, S.

1988-01-01

84

FKBP12 Controls Aspartate Pathway Flux in Saccharomyces cerevisiae To Prevent Toxic Intermediate Accumulation  

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FKBP12 is a conserved member of the prolyl-isomerase enzyme family and serves as the intracellular receptor for FK506 that mediates immunosuppression in mammals and antimicrobial actions in fungi. To investigate the cellular functions of FKBP12 in Saccharomyces cerevisiae, we employed a high-throughput assay to identify mutations that are synthetically lethal with a mutation in the FPR1 gene, which encodes FKBP12. This screen identified a mutation in the HOM6 gene, which encodes homoserine de...

Are?valo-rodri?guez, Miguel; Pan, Xuewen; Boeke, Jef D.; Heitman, Joseph

2004-01-01

85

Fermentation of High Concentrations of Maltose by Saccharomyces cerevisiae Is Limited by the COMPASS Methylation Complex?  

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In Saccharomyces cerevisiae, genes encoding maltose permeases and maltases are located in the telomeric regions of different chromosomes. The COMPASS methylation complex, which methylates lysine 4 on histone H3, controls the silencing of telomeric regions. Yeast strains deleted for SWD1, SWD3, SDC1, SET1, BRE2, or SPP1, encoding components of the COMPASS complex, fermented a medium containing 22% maltose with noticeably higher attenuation than did the wild type, resulting in production of up ...

Houghton-larsen, Jens; Brandt, Anders

2006-01-01

86

Substrate Specificity of Thiamine Pyrophosphate-Dependent 2-Oxo-Acid Decarboxylases in Saccharomyces cerevisiae:  

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Fusel alcohols are precursors and contributors to flavor and aroma compounds in fermented beverages, and some are under investigation as biofuels. The decarboxylation of 2-oxo acids is a key step in the Ehrlich pathway for fusel alcohol production. In Saccharomyces cerevisiae, five genes share sequence similarity with genes encoding thiamine pyrophosphate-dependent 2-oxo-acid decarboxylases (2ODCs). PDC1, PDC5, and PDC6 encode differentially regulated pyruvate decarboxylase isoenzymes; ARO10 ...

Romagnoli, G.; Luttik, M. A. H.; Ko?tter, P.; Pronk, J. T.; Daran, J. M.

2012-01-01

87

Import of alcohol oxidase into peroxisomes of Saccharomyces cerevisiae.  

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Saccharomyces cerevisiae is unable to grow on methanol because it lacks the enzymes required for its metabolism. To study the possibility of whether or not the methanol oxidation pathway of Hansenula polymorpha can be transferred to S. cerevisiae, the gene coding for alcohol oxidase, a peroxisomal homo-octameric flavoprotein, was introduced into S. cerevisiae. Transformed cells contain varying amounts of alcohol oxidase depending on the plasmid used. Immunocytochemical experiments indicate th...

Distel, B.; Veenhuis, M.; Tabak, H. F.

1987-01-01

88

Evolutionary Engineering of Saccharomyces cerevisiae for Anaerobic Growth on Xylose  

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Xylose utilization is of commercial interest for efficient conversion of abundant plant material to ethanol. Perhaps the most important ethanol-producing organism, Saccharomyces cerevisiae, however, is incapable of xylose utilization. While S. cerevisiae strains have been metabolically engineered to utilize xylose, none of the recombinant strains or any other naturally occurring yeast has been able to grow anaerobically on xylose. Starting with the recombinant S. cerevisiae strain TMB3001 tha...

Sonderegger, Marco; Sauer, Uwe

2003-01-01

89

Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains  

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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 selection 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...

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

2010-01-01

90

Identification of a Cryptococcus neoformans gene that directs expression of the cryptic Saccharomyces cerevisiae mannitol dehydrogenase gene.  

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The Mtl gene from Cryptococcus neoformans, which confers the ability of Saccharomyces cerevisiae Sc4l YJO to grow on mannitol with substantial NAD-dependent mannitol dehydrogenase activity, was identified. Purifications and characterizations of this enzyme show that it is found in polyploid strain BB1, and the peptide sequence of the enzyme helped identify the saccharomyces gene encoding this mannitol dehydrogenase activity. On the other hand, the Mtl gene of C. neoformans encodes a 346-amino...

Perfect, J. R.; Rude, T. H.; Wong, B.; Flynn, T.; Chaturvedi, V.; Niehaus, W.

1996-01-01

91

A mutation in NPS1/STH1, an essential gene encoding a component of a novel chromatin-remodeling complex RSC, alters the chromatin structure of Saccharomyces cerevisiae centromeres.  

Science.gov (United States)

The NPS1/STH1 gene encodes a nuclear protein essential for the progression of G2/M phase in Saccharomyces cerevisiae . Nps1p shares homology to Snf2/Swi2p, a subunit of a protein complex known as the SNF/SWI complex. Recently, Nps1p was found to be a component of a protein complex termed RSC (3) essential for mitotic growth, whereas its function is unknown. We isolated a temperature-sensitive mutant allele of NPS1 , nps1-105, and found that the mutation increases the sensitivity to thiabendazole (TBZ). At the restrictive temperature, nps1-105 arrested at the G2/M phase in MAD1-dependent manner and missegregated the mini-chromosome with higher frequency than the wild type cells. The nuclease digestion of the chromatin of the mutant cells revealed that the mutation causes the alteration of the chromatin structure around centromeres at the restrictive temperature. The results suggested that, in the nps1-105 mutant, impaired chromatin structure surrounding centromeres may lead to an impairment of kinetochore function and the cells arrest at G2/M phase through the spindle-assembly checkpoint system. PMID:9628931

Tsuchiya, E; Hosotani, T; Miyakawa, T

1998-07-01

92

Redox balancing in recombinant strains of Saccharomyces cerevisiae  

Energy Technology Data Exchange (ETDEWEB)

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

Anderlund, M.

1998-09-01

93

Directed Evolution towards Increased Isoprenoid Production in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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

Carlsen, Simon; Nielsen, Michael Lynge

94

Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

Weinert, Brian Tate; Iesmantavicius, Vytautas

2014-01-01

95

Switching the mode of sucrose utilization by Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

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.

Miletti Luiz C

2008-02-01

96

ISOTERMAS DE ADSORÇÃO DE CÁDMIO POR Saccharomyces cerevisiae  

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Com o objetivo de determinar as isotermas de adsorção de cádmio por Saccharomyces cerevisiae, foram utilizados os sais cloreto e nitrato de cádmio nas concentrações de 5, 10, 20, 40, 60, 80 e 100mg L-1. A biomassa foi produzida a partir de uma cultura "starter"de Saccharomyces cerevisiae IZ 1904. Após o contato de 16h entre o microrganismo e as soluções em estudo, a biomassa foi separada por centrifugação e o teor de cádmio residual foi determinado no sobrenadante por espectrofoto...

Albertini, Silvana; Carmo, Leandro Francisco Do; Prado Filho, Luiz Gonzaga Do

2001-01-01

97

Accumulation of gold using Baker's yeast, Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Authors have reported preconcentration of 152Eu, a long-lived fission product, by yeast cells, Saccharomyces cerevisiae. Gold being a precious metal is used in electroplating, hydrogenation catalyst, etc. Heterogeneous composition of samples and low concentration offers renewed interest in its selective extraction of gold using various extractants. Gold can be recovered from different solutions using various chemical reagents like amines, organophosphorus compounds, and extractants containing sulphur as donor atom, etc. In the present work, two different strains of baker's yeast, Saccharomyces cerevisiae have been used to study the preconcentration of gold at various experimental conditions

98

Synthesis of Semliki Forest virus RNA polymerase components nsP1 through nsP4 in Saccharomyces cerevisiae by expression of cDNA encoding the nonstructural polyprotein.  

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A Semliki Forest virus nonstructural polyprotein, P1234, expressed in the yeast Saccharomyces cerevisiae in the absence of a replicative RNA template appeared to be properly cleaved into nsP1 to nsP4. All nsPs were membrane associated, and nsP2 was also transported to the nucleus. The membrane fraction containing nsPs showed guanine-7-methyltransferase and guanylyltransferase-like activities, typical for Semliki Forest virus nsP1.

Russo, P.; Laakkonen, P.; Ahola, T.; Ka?a?ria?inen, L.

1996-01-01

99

RPO41-independent maintenance of [rho-] mitochondrial DNA in Saccharomyces cerevisiae.  

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A subset of promoters in the mitochondrial DNA (mtDNA) of the yeast Saccharomyces cerevisiae has been proposed to participate in replication initiation, giving rise to a primer through site-specific cleavage of an RNA transcript. To test whether transcription is essential for mtDNA maintenance, we examined two simple mtDNA deletion ([rho-]) genomes in yeast cells. One genome (HS3324) contains a consensus promoter (ATATAAGTA) for the mitochondrial RNA polymerase encoded by the nuclear gene RPO...

Fangman, W. L.; Henly, J. W.; Brewer, B. J.

1990-01-01

100

Bub1p Kinase Activates the Saccharomyces cerevisiae Spindle Assembly Checkpoint  

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Saccharomyces cerevisiae BUB1 encodes a protein kinase required for spindle assembly checkpoint function. In the presence of spindle damage, BUB1 is required to prevent cell cycle progression into anaphase. We have identified a dominantly acting BUB1 allele that appears to activate the spindle assembly checkpoint pathway in cells with undamaged spindles. High-level expression of BUB1-5 did not cause detectable spindle damage, yet it delayed yeast cells in mitosis at a stage following bipolar ...

Farr, Katie A.; Hoyt, M. Andrew

1998-01-01

 
 
 
 
101

Metabolic Engineering of Saccharomyces cerevisiae for Astaxanthin Production and Oxidative Stress Tolerance?  

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The red carotenoid astaxanthin possesses higher antioxidant activity than other carotenoids and has great commercial potential for use in the aquaculture, pharmaceutical, and food industries. In this study, we produced astaxanthin in the budding yeast Saccharomyces cerevisiae by introducing the genes involved in astaxanthin biosynthesis of carotenogenic microorganisms. In particular, expression of genes of the red yeast Xanthophyllomyces dendrorhous encoding phytoene desaturase (crtI product)...

Ukibe, Ken; Hashida, Keisuke; Yoshida, Nobuyuki; Takagi, Hiroshi

2009-01-01

102

Saccharomyces cerevisiae Nip7p is required for efficient 60S ribosome subunit biogenesis.  

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The Saccharomyces cerevisiae temperature-sensitive (ts) allele nip7-1 exhibits phenotypes associated with defects in the translation apparatus, including hypersensitivity to paromomycin and accumulation of halfmer polysomes. The cloned NIP7+ gene complemented the nip7-1 ts growth defect, the paromomycin hypersensitivity, and the halfmer defect. NIP7 encodes a 181-amino-acid protein (21 kDa) with homology to predicted products of open reading frames from humans, Caenorhabditis elegans, and Ara...

Zanchin, N. I.; Roberts, P.; Desilva, A.; Sherman, F.; Goldfarb, D. S.

1997-01-01

103

Genomewide Screen Reveals a Wide Regulatory Network for Di/Tripeptide Utilization in Saccharomyces cerevisiae  

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Small peptides of two to six residues serve as important sources of amino acids and nitrogen required for growth by a variety of organisms. In the yeast Saccharomyces cerevisiae, the membrane transport protein Ptr2p, encoded by PTR2, mediates the uptake of di/tripeptides. To identify genes involved in regulation of dipeptide utilization, we performed a systematic, functional examination of this process in a haploid, nonessential, single-gene deletion mutant library. We have identified 103 can...

Cai, Houjian; Kauffman, Sarah; Naider, Fred; Becker, Jeffrey M.

2006-01-01

104

Recapitulation in Saccharomyces cerevisiae of Cytochrome b Mutations Conferring Resistance to Atovaquone in Pneumocystis jiroveci  

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Pneumocystis jiroveci (human-derived P. carinii) is an opportunistic pathogenic fungus which causes pneumonia and is life-threatening in immunocompromised individuals. Spontaneously acquired resistance to atovaquone, a hydroxynaphthoquinone that is used to treat P. jiroveci infections, was linked to mutations in the mitochondrially encoded cytochrome b gene. Because P. jiroveci cannot be easily cultivated, we have developed Saccharomyces cerevisiae as an alternative system to study atovaquone...

Hill, Philip; Kessl, Jacques; Fisher, Nicholas; Meshnick, Steven; Trumpower, Bernard L.; Meunier, Brigitte

2003-01-01

105

Thiamine Biosynthesis in Saccharomyces cerevisiae Is Regulated by the NAD+-Dependent Histone Deacetylase Hst1? †  

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Genes encoding thiamine biosynthesis enzymes in microorganisms are tightly regulated such that low environmental thiamine concentrations activate transcription and high concentrations are repressive. We have determined that multiple thiamine (THI) genes in Saccharomyces cerevisiae are also regulated by the intracellular NAD+ concentration via the NAD+-dependent histone deacetylase (HDAC) Hst1 and, to a lesser extent, Sir2. Both of these HDACs associate with a distal region of the affected THI...

Li, Mingguang; Petteys, Brian J.; Mcclure, Julie M.; Valsakumar, Veena; Bekiranov, Stefan; Frank, Elizabeth L.; Smith, Jeffrey S.

2010-01-01

106

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

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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...

Budd, M. E.; Campbell, J. L.

1993-01-01

107

Saccharomyces cerevisiae genomic library screening in search for the gene responsible for inductive active glycerol uptake  

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In Saccharomyces cerevisiae, physiological response to osmotic stress is done, mainly, by increased synthesis and intracellular accumulation of glycerol as compatible solute. Previous studies revealed the existence of a glycerol/H+ symport, inducible by growth under gluconeogenic conditions (Lages and Lucas) and independent of the Fps1 channel for glycerol (Sutherland et al.). In order to isolate the gene encoding for glycerol specific carrier, an isogenic strain to W303- 1A...

Oliveira, Rui Pedro Soares; Lucas, Ca?ndida

1997-01-01

108

Aquaporin-Mediated Improvement of Freeze Tolerance of Saccharomyces cerevisiae Is Restricted to Rapid Freezing Conditions  

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Previous observations that aquaporin overexpression increases the freeze tolerance of baker's yeast (Saccharomyces cerevisiae) without negatively affecting the growth or fermentation characteristics held promise for the development of commercial baker's yeast strains used in frozen dough applications. In this study we found that overexpression of the aquaporin-encoding genes AQY1-1 and AQY2-1 improves the freeze tolerance of industrial strain AT25, but only in small doughs under laboratory co...

Tanghe, An; Dijck, Patrick; Colavizza, Didier; Thevelein, Johan M.

2004-01-01

109

The Mitochondrial Alcohol Dehydrogenase Adh3p Is Involved in a Redox Shuttle in Saccharomyces cerevisiae  

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NDI1 is the unique gene encoding the internal mitochondrial NADH dehydrogenase of Saccharomyces cerevisiae. The enzyme catalyzes the transfer of electrons from intramitochondrial NADH to ubiquinone. Surprisingly, NDI1 is not essential for respiratory growth. Here we demonstrate that this is due to in vivo activity of an ethanol-acetaldehyde redox shuttle, which transfers the redox equivalents from the mitochondria to the cytosol. Cytosolic NADH can be oxidized by the external NADH dehydrogena...

Bakker, B. M.; Bro, C.; Kotter, P.; Luttik, M. A.; Dijken, J. P.; Pronk, J. T.

2000-01-01

110

Engineering and Analysis of a Saccharomyces cerevisiae Strain That Uses Formaldehyde as an Auxiliary Substrate?  

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We demonstrated that formaldehyde can be efficiently coutilized by an engineered Saccharomyces cerevisiae strain that expresses Hansenula polymorpha genes encoding formaldehyde dehydrogenase (FLD1) and formate dehydrogenase (FMD), in contrast to wild-type strains. Initial chemostat experiments showed that the engineered strain coutilized formaldehyde with glucose, but these mixed-substrate cultures failed to reach steady-state conditions and did not exhibit an increased biomass yield on gluco...

Baerends, Richard J. S.; Hulster, Erik; Geertman, Jan-maarten A.; Daran, Jean-marc; Maris, Antonius J. A.; Veenhuis, Marten; Klei, Ida J.; Pronk, Jack T.

2008-01-01

111

Characterization of the glucose-induced inactivation of maltose permease in Saccharomyces cerevisiae.  

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The addition of glucose to maltose-fermenting Saccharomyces cerevisiae cells causes a rapid and irreversible loss of the ability to transport maltose, resulting both from the repression of transcription of the maltose permease gene and from the inactivation of maltose permease. The latter is referred to as glucose-induced inactivation or catabolite inactivation. We describe an analysis of this process in a maltose-fermenting strain expressing a hemagglutinin (HA)-tagged allele of MAL61, encod...

Medintz, I.; Jiang, H.; Han, E. K.; Cui, W.; Michels, C. A.

1996-01-01

112

Adaptive Evolution of a Lactose-Consuming Saccharomyces cerevisiae Recombinant?  

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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 ...

Guimara?es, Pedro M. R.; Franc?ois, J.; Parrou, J. L.; Teixeira, J. A.; Domingues, Luci?lia

2008-01-01

113

Completion of Replication Map of Saccharomyces cerevisiae Chromosome III  

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In Saccharomyces cerevisiae chromosomal DNA replication initiates at intervals of ?40 kb and depends upon the activity of autonomously replicating sequence (ARS) elements. The identification of ARS elements and analysis of their function as chromosomal replication origins requires the use of functional assays because they are not sufficiently similar to identify by DNA sequence analysis. To complete the systematic identification of ARS elements on S. cerevisiae chromosome III, overlapping c...

Poloumienko, Arkadi; Dershowitz, Ann; De, Jitakshi; Newlon, Carol S.

2001-01-01

114

Isolation of yeast Saccharomyces cerevisiae from unusual natural habitats  

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Baker yeast Saccharomyces cerevisiae has been an eukarontic experimental organism since 1960s, becoming even more significant with the determination of its complete nucleotide genome sequence in 1996. Even though its biochemical function in the fermentation process had long remained unclear, its metabolism and products (eg. bread, beer, wine) have been used for millennia. S. cerevisiae yeast represents an important organism for production of recombinant proteins (gene manipulation). Moreover,...

Finz?gar, Bernarda

2012-01-01

115

Fenpropimorph affects uptake of uracil and cytosine in Saccharomyces cerevisiae.  

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Fenpropimorph was shown to inhibit the accumulation of the pyrimidine bases uracil and cytosine from the growth media in Saccharomyces cerevisiae. Uracil prototrophs of S. cerevisiae were more resistant to the growth-inhibitory effects of fenpropimorph than were uracil auxotrophs. High concentrations of uracil rescued fenpropimorph-treated uracil auxotrophs, and cytosine, which is accumulated by a separate mechanism, could also support growth of treated uracil auxotrophs. Fenpropimorph caused...

Crowley, J. H.; Lorenz, R. T.; Parks, L. W.

1994-01-01

116

Switching the mode of metabolism in the yeast Saccharomyces cerevisiae  

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The biochemistry of most metabolic pathways is conserved from bacteria to humans, although the control mechanisms are adapted to the needs of each cell type. Oxygen depletion commonly controls the switch from respiration to fermentation. However, Saccharomyces cerevisiae also controls that switch in response to the external glucose level. We have generated an S. cerevisiae strain in which glucose uptake is dependent on a chimeric hexose transporter mediating reduced sugar uptake. This strain ...

Otterstedt, Karin; Larsson, Christer; Bill, Roslyn M.; Sta?hlberg, Anders; Boles, Eckhard; Hohmann, Stefan; Gustafsson, Lena

2004-01-01

117

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

118

Role of social wasps in Saccharomyces cerevisiae ecology and evolution  

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Saccharomyces cerevisiae is one of the most important model organisms and has been a valuable asset to human civilization. However, despite its extensive use in the last 9,000 y, the existence of a seasonal cycle outside human-made environments has not yet been described. We demonstrate the role of social wasps as vector and natural reservoir of S. cerevisiae during all seasons. We provide experimental evidence that queens of social wasps overwintering as adults (Vespa crabro and Polistes spp...

Stefanini, Irene; Dapporto, Leonardo; Legras, Jean-luc; Calabretta, Antonio; Di Paola, Monica; Filippo, Carlotta; Viola, Roberto; Capretti, Paolo; Polsinelli, Mario; Turillazzi, Stefano; Cavalieri, Duccio

2012-01-01

119

Transcriptional responses to glucose in Saccharomyces cerevisiae strains lacking a functional protein kinase A  

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[Background]: The pattern of gene transcripts in the yeast Saccharomyces cerevisiae is strongly affected by the presence of glucose. An increased activity of protein kinase A (PKA), triggered by a rise in the intracellular concentration of cAMP, can account for many of the effects of glucose on transcription. In S. cerevisiae three genes, TPK1, TPK2, and TPK3, encode catalytic subunits of PKA. The lack of viability of tpk1 tpk2 tpk3 triple mutants may be suppressed by mutations such as yak1 o...

Livas, Daniela; Gancedo, Juana M.

2011-01-01

120

Filament formation in Saccharomyces cerevisiae--a review.  

Science.gov (United States)

Many yeasts can produce filamentous elongated cells identifiable as hyphae, pseudohyphae or invasive filaments. Filament formation has been understood as a foraging response that occurs in nutrient-poor conditions. However, fusel alcohols were observed to induce filament formation in rich nutrient conditions in every yeast species examined. Fusel alcohols, e.g., 3-methyl-1-butanol (3Me-BuOH; 'isoamyl alcohol'), 2-methyl-1-propanol (isobutyl alcohol), (-)-2-methyl-1-butanol ('active amyl alcohol'), 2-phenylethanol and 3-(2-hydroxyethyl)indole (tryptophol) (the end products of leucine, valine, isoleucine, phenylalanine and tryptophan catabolism, respectively) are the end products of amino acid catabolism that accumulate when nutrients become limiting. Thus, yeast responds to its own metabolic by-products. Considerable effort was made to define the cell biological and biochemical changes that take place during 3Me-BuOH-induced filamentation. In Saccharomyces cerevisiae filaments contain significantly greater mitochondrial mass and increased chitin content in comparison with yeast-form cells. The global transcriptional response of S. cerevisiae during the early stages of 3Me-BuOH-induced filament formation has been described. Four ORFs displayed very significant (more than 10-fold) increases in their RNA species, and 12 ORFs displayed increases in transcription of more than 5-fold. The transcription of five genes (all of which encode transporters) decreased by similar amounts. Where examined, the activity of the proteins encoded reflected the transcriptional pattern of their respective mRNAs. To understand this regulation, studies were performed to see whether deletion or overexpression of key genes affects the ability to filament and invade solid YEPD medium. This has led to identification of those proteins that are essential for filament formation, repressors and those which are simply not required. It also leads to the conclusion that 3Me-BuOH-induced filament formation is not a foraging response but a response to reduced growth rate. PMID:18481212

Dickinson, J R

2008-01-01

 
 
 
 
121

Saccharomyces cerevisiae IRE2/HAC1 is involved in IRE1-mediated KAR2 expression.  

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The Saccharomyces cerevisiae IRE1 gene, encoding a putative receptor-type protein kinase, is known to be required for inositol prototrophy and for the induction of a chaperon molecule, BiP, encoded by KAR2, under stress conditions such as tunicamycin addition. We have characterized a yeast gene, IRE2, which was isolated as a suppressor gene that complements the inositol auxotrophic phenotype of the ire1 mutation. Sequencing analysis revealed that IRE2 is identical to HAC1, which encodes a tra...

Nikawa, J.; Akiyoshi, M.; Hirata, S.; Fukuda, T.

1996-01-01

122

Structural and functional analysis of the MAL1 locus of Saccharomyces cerevisiae.  

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We describe the isolation of a 22.6-kilobase fragment of DNA containing the MAL1 locus of Saccharomyces cerevisiae. Our results demonstrate that the MAL1 locus, like the MAL6 locus, is a complex locus containing three genes. These genes were organized similarly to their MAL6 counterparts. We refer to them as MAL11, MAL12, and MAL13 and show that they are functionally homologous to the MAL61 (encoding maltose permease), MAL62 (encoding maltase), and MAL63 (encoding the positive regulator) gene...

Charron, M. J.; Dubin, R. A.; Michels, C. A.

1986-01-01

123

Genetiese manipulering van die gis Saccharomyces cerevisiae betreffende polisakkariedbenutting Genetiese manipulering van die gis Saccharomyces cerevisiae betreffende polisakkariedbenutting  

Directory of Open Access Journals (Sweden)

Full Text Available Die gis Saccharomyces cerevisiae word wêreldwyd as die belangrikste kommersiële mikro-organisme bestempel en geniet sogenaamde ABAV-status (Algemeen Beskou As Veilig weens dié gis se eeue lange verbintenis met voedselproduksie (bv. brood, wyn, bier, proteienaanvulling en geurstowwe.Die gis Saccharomyces cerevisiae word wêreldwyd as die belangrikste kommersiële mikro-organisme bestempel en geniet sogenaamde ABAV-status (Algemeen Beskou As Veilig weens dié gis se eeue lange verbintenis met voedselproduksie (bv. brood, wyn, bier, proteienaanvulling en geurstowwe.

I. S. Pretoruis

1992-07-01

124

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

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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...

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

2011-01-01

125

The enantioselective b-keto ester reductions by Saccharomyces cerevisiae  

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The enantioselective yeast reduction of aromatic b-keto esters, by use of potassium dihydrogen phosphate, calcium phosphate (monobasic), magnesium sulfate and ammonium tartrate (diammonium salt) (10:1:1:50) in water at pH 7 as a buffer for 72–120 h with 45–90 % conversion to the corresponding aromatic -hydroxy esters was achieved by means of Saccharomyces cerevisiae.

HASSAN TAJIK; KHALIL TABATABAEIAN; MAHMOOD SHAHBAZI

2006-01-01

126

Analysis of the RNA Content of the Yeast "Saccharomyces Cerevisiae"  

Science.gov (United States)

In this article, the authors describe an interconnected set of relatively simple laboratory experiments in which students determine the RNA content of yeast cells and use agarose gel electrophoresis to separate and analyze the major species of cellular RNA. This set of experiments focuses on RNAs from the yeast "Saccharomyces cerevisiae", a…

Deutch, Charles E.; Marshall, Pamela A.

2008-01-01

127

Kinetics of formation of induced mutants of Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

UV and ?-radiation mutagenic effect an various strains of Saccharomyces cerevisiae was studied by analyzing formation kinetics of induced mutants at the period of postirradiation incubation. Mechanisms of induced reverse formation was suggested. The presented analysis is considered to be differential taking account of more subtle aspects of induced mutagenesis. 8 refs.; 10 figs.; 3 tabs

128

Evidence against a photoprotective component of photoreactivation in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Photoreactivation-deficient (phr-) mutants of Saccharomyces cerevisiae were shown to lack in vitro DNA-photolyase activity. A phr- mutant was then compared with a phr+ strain for near-UV induced photoprotection from far-UV irradiation. Neither strain exhibited a photoprotective effect. (author)

129

Effects of mycotoxins on the fermenting activity of Saccharomyces cerevisiae  

Energy Technology Data Exchange (ETDEWEB)

The rate of fermentation of Saccharomyces cerevisiae is partially inhibited by different mycotoxins. This effect is remarkable with T2-toxin and diacetoxyscirpenol, slight with aflatoxin-B1, penicillic acid and patulin. On the contrary, the butenolide appears as a stimulator of the alcoholic fermentation. (Refs. 17).

Lafont, J.; Romand, A.; Lafont, P.

1981-05-01

130

Production of ?-galactosidase from recombinant Saccharomyces cerevisiae grown on lactose  

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Improved productivity and costs reduction in fermentation processes may be attained by using flocculating cell cultures. The production of extracellular heterologous ?-galactosidase by recombinant flocculating Saccharomyces cerevisiae cells, expressing the lacA gene (coding for ?-galactosidase) of Aspergillus niger under the ADHI promotor and terminator in a bioreactor was studied. The effects of lactose concentration and yeast extract concentration on ?-galactosidase productio...

Domingues, Luci?lia; Oliveira, Carla Cristina Marques; Castro, I.; Lima, Nelson; Teixeira, J. A.

2004-01-01

131

Production of Yarrowia lipolytica Nha2 Na+/H+ antiporter improves the salt tolerance of Saccharomyces cerevisiae.  

Science.gov (United States)

Yarrowia lipolytica plasma-membrane Na+/H+ antiporter, encoded by the YlNHA2 gene, is a very efficient exporter of surplus sodium from the cytosol. Its heterologous expression in Saccharomyces cerevisiae wild-type laboratory strains increased their sodium tolerance more efficiently than the expression of ZrSod2-22 antiporter from the osmotolerant yeast Zygosaccharomvces rouxii. PMID:18450222

Papousková, K; Sychrová, H

2007-01-01

132

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

DEFF Research Database (Denmark)

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.

van der Aa Kuhle, Alis; Skovgaard, Kerstin

2005-01-01

133

Using regulatory information to manipulate glycerol metabolism in Saccharomyces cerevisiae.  

Science.gov (United States)

Metabolic engineering has emerged as an attractive alternative to random mutagenesis and screening to design cell factories for industrial fermentation processes. The design of metabolic networks has been realized by gene deletions or strong overexpression of heterologous genes. There is an increasing body of evidence that indicates complete inactivation of native genes and high-level activity of heterologous enzymes may be deleterious to the cell. To moderately implement their expression, genes of interest are expressed under the control of promoters with different strengths. Constructing a promoter library is labor-intensive and requires precise quantification of the promoter strength. However, when the mechanisms of pathway regulation are known, it is possible to exploit this information to effect genetic changes efficiently. We report the implementation of this concept to reducing glycerol production during aerobic growth of Saccharomyces cerevisiae. Glycerol is produced to dispose excess cytosolic reduced nicotinamide adenine dinucleotide (NADH), and the regulating step in the pathway is mediated by glycerol 3-phosphate dehydrogenase (encoded by GPD1 and GPD2 genes). We expressed NADH oxidase in S. cerevisiae under the control of the GPD2 promoter to modulate the decrease in cytosolic NADH to the right level where the heterologous enzyme does not compete with oxidative phosphorylation while at the same time, decreasing glycerol production. This metabolic design resulted in substantially decreasing glycerol production and indeed, the excess carbon was redirected to biomass, resulting in a 14% increase in the specific growth rate. We believe that such strategies are more efficient than conventional methods and will find applications in bioprocesses. PMID:19727706

Hou, Jin; Vemuri, Goutham N

2010-01-01

134

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)

135

ISOTERMAS DE ADSORÇÃO DE CÁDMIO POR Saccharomyces cerevisiae ISOTHERMS OF CADMIUM ADSORPTION BY Saccharomyces cerevisae  

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Com o objetivo de determinar as isotermas de adsorção de cádmio por Saccharomyces cerevisiae, foram utilizados os sais cloreto e nitrato de cádmio nas concentrações de 5, 10, 20, 40, 60, 80 e 100mg L-1. A biomassa foi produzida a partir de uma cultura "starter"de Saccharomyces cerevisiae IZ 1904. Após o contato de 16h entre o microrganismo e as soluções em estudo, a biomassa foi separada por centrifugação e o teor de cádmio residual foi determinado no sobrenadante por espectrofoto...

Albertini, Silvana; Carmo, Leandro Francisco Do; Prado Filho, Luiz Gonzaga Do

2001-01-01

136

Transcriptional induction by aromatic amino acids in Saccharomyces cerevisiae.  

Science.gov (United States)

Aromatic aminotransferase II, product of the ARO9 gene, catalyzes the first step of tryptophan, phenylalanine, and tyrosine catabolism in Saccharomyces cerevisiae. ARO9 expression is under the dual control of specific induction and nitrogen source regulation. We have here identified UASaro, a 36-bp upstream element necessary and sufficient to promote transcriptional induction of reporter gene expression in response to tryptophan, phenylalanine, or tyrosine. We then isolated mutants in which UASaro-mediated ARO9 transcription is partially or totally impaired. Mutations abolishing ARO9 induction affect a gene called ARO80 (YDR421w), coding for a Zn2Cys6 family transcription factor. A sequence highly similar to UASaro was found upstream from the YDR380w gene encoding a homolog of bacterial indolepyruvate decarboxylase. In yeast, this enzyme is postulated to catalyze the second step of tryptophan catabolism to tryptophol. We show that ARO9 and YDR380w (named ARO10) have similar patterns of transcriptional regulation and are both under the positive control of Aro80p. Nitrogen regulation of ARO9 expression seems not directly to involve the general factor Ure2p, Gln3p, Nil1p, Uga43p, or Gzf3p. ARO9 expression appears, rather, to be mainly regulated by inducer exclusion. Finally, we show that Gap1p, the general amino acid permease, and Wap1p (Ycl025p), a newly discovered inducible amino acid permease with broad specificity, are the main aromatic amino acid transporters for catabolic purposes. PMID:10207060

Iraqui, I; Vissers, S; André, B; Urrestarazu, A

1999-05-01

137

Characterization of a mitochondrial inorganic pyrophosphatase in Saccharomyces cerevisiae.  

Science.gov (United States)

We have studied a mitochondrial inorganic pyrophosphatase (PPase) in the yeast Saccharomyces cerevisiae. The uncoupler FCCP (carbonyl cyanide p-trifluoromethoxyphenylhydrazone) and the ionophores valinomycin and nigericin stimulate the PPase activity of repeatedly washed yeast mitochondria 2-3-fold. We have previously cloned a yeast gene, PPA2, encoding the catalytic subunit of a mitochondrial PPase. Uncouplers stimulate the PPase activity several-fold in mitochondria from both cells that overexpress PPA2 from a high copy number plasmid and cells with normal expression. These results indicate that the PPA2 polypeptide functions as an energy linked and membrane associated PPase. The stimulation of mitochondrial PPase activity by FCCP, but not by valinomycin and nigericin, was greatly enhanced by the presence of DTT. The antibiotics Dio-9, equisetin and the F0F1-ATPase inhibitor oligomycin also increase mitochondrial PPase activity several fold. This stimulation is much higher, whereas basal PPase activity is lower, in isotonic than in hypotonic solution, which indicates that intact membranes are a prerequisite for maximal effects. PMID:1309654

Lundin, M; Deopujari, S W; Lichko, L; da Silva, L P; Baltscheffsky, H

1992-01-16

138

Two independent activities define Ccm1p as a moonlighting protein in Saccharomyces cerevisiae  

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Ccm1p is a nuclear-encoded PPR (pentatricopeptide repeat) protein that localizes into mitochondria of Saccharomyces cerevisiae. It was first defined as an essential factor to remove the bI4 [COB (cytochrome b) fourth intron)] and aI4 [COX1 (cytochrome c oxidase subunit 1) fourth intron] of pre-mRNAs, along with bI4 maturase, a protein encoded by part of bI4 and preceding exons that removes the intronic RNA sequence that codes for it. Later on, Ccm1p was described as key to maintain the steady...

Ignacio Moreno, J.; Babu Patlolla; Belton, Kerry X. A. R.; Jenkins, Brenita X. A. C.; Radchenkova, Polina X. A. V.; Piva, Marta X. A. A.

2012-01-01

139

l-Proline Accumulation and Freeze Tolerance in Saccharomyces cerevisiae Are Caused by a Mutation in the PRO1 Gene Encoding ?-Glutamyl Kinase  

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We previously isolated a mutant which showed a high tolerance to freezing that correlated with higher levels of intracellular l-proline derived from l-proline analogue-resistant mutants. The mutation responsible for the analogue resistance and l-proline accumulation was a single nuclear dominant mutation. By introducing the mutant-derived genomic library into a non-l-proline-utilizing strain, the mutant was found to carry an allele of the wild-type PRO1 gene encoding ?-glutamyl kinase, which...

Morita, Yuko; Nakamori, Shigeru; Takagi, Hiroshi

2003-01-01

140

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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.

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

2004-06-01

 
 
 
 
141

Evolutionary engineering of Saccharomyces cerevisiae for efficient aerobic xylose consumption.  

DEFF Research Database (Denmark)

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.

Scalcinati, Gionata; Otero, José Manuel

2012-01-01

142

Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae.  

Directory of Open Access Journals (Sweden)

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.

2005-07-01

143

Saccharomyces cerevisiae contains a Type II phosphoinositide 4-kinase.  

Science.gov (United States)

The yeast Saccharomyces cerevisiae contains two known phosphoinositide 4-kinases (PI 4-kinases), which are encoded by PIK1 and STT4; both are essential. Pik1p is important for exocytic transport from the Golgi, whereas Stt4p plays a role in cell-wall integrity and cytoskeletal rearrangements. In the present study, we report that cells have a third PI 4-kinase activity encoded by LSB6, a protein identified previously in a two-hybrid screen as interacting with LAS17p. Although Pik1p and Stt4p are closely related members of the Type III class of PI 4-kinases, Lsb6p belongs to the distinct Type II class, based on its amino acid sequence, its sensitivity to inhibition by adenosine and its insensitivity to wortmannin. Lsb6p is the first fungal Type II enzyme cloned. The protein was expressed and purified from Sf9 cells and used to define kinetic parameters. As commonly observed for surface-active enzymes, activities varied both with substrate concentration and lipid/detergent molar ratios. Maximal activities of approx. 100 min(-1) were obtained at the PI/Triton X-100 ratio of 1:5. The K (m) value for ATP was 266 microM, intermediate between the values reported for mammalian Type II and III kinases. Epitope-tagged protein, expressed in yeast, was entirely particulate, and about half of it could be extracted with non-ionic detergent. Lsb6p-green fluorescent protein was found both on vacuolar membranes and on the plasma membrane, suggesting a role in endocytic or exocytic pathways. PMID:12523934

Shelton, Shary N; Barylko, Barbara; Binns, Derk D; Horazdovsky, Bruce F; Albanesi, Joseph P; Goodman, Joel M

2003-01-01

144

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

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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 Saccha...

Bajaj, Bijender K.; Sharma, S.

2010-01-01

145

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)

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.

Færgeman, Nils J.; Black, P N

2001-01-01

146

The putative phosphoinositide-specific phospholipase C gene, PLC1, of the yeast Saccharomyces cerevisiae is important for cell growth.  

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Using the polymerase chain reaction technique, we have isolated a gene that encodes a putative phosphoinositide-specific phospholipase C (PLC) in the yeast Saccharomyces cerevisiae. The nucleotide sequence indicates that the gene encodes a polypeptide of 869 amino acid residues with a calculated molecular mass of 101 kDa. This polypeptide has both the X and Y regions conserved among mammalian PLC-beta, -gamma, and -delta, and the structure is most similar to that of mammalian PLC-delta. This ...

Yoko-o, T.; Matsui, Y.; Yagisawa, H.; Nojima, H.; Uno, I.; Toh-e, A.

1993-01-01

147

Unlinked Noncomplementation: Isolation of New Conditional-Lethal Mutations in Each of the Tubulin Genes of Saccharomyces Cerevisiae  

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Mutations in genes of Saccharomyces cerevisiae that code for proteins that interact with ?-tubulin were sought by screening for unlinked mutations that fail to complement mutations in the single ?-tubulin-encoding gene (TUB2). Among the first three noncomplementing mutations examined, two are linked to TUB2 while one is unlinked. The unlinked mutation was shown to be a conditional-lethal allele of the major ?-tubulin-encoding gene (TUB1) and represents the first such mutation in that gene....

Stearns, T.; Botstein, D.

1988-01-01

148

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

Directory of Open Access Journals (Sweden)

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.

Pejin Dušanka J.

2005-01-01

149

ISOTERMAS DE ADSORÇÃO DE CÁDMIO POR Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available Com o objetivo de determinar as isotermas de adsorção de cádmio por Saccharomyces cerevisiae, foram utilizados os sais cloreto e nitrato de cádmio nas concentrações de 5, 10, 20, 40, 60, 80 e 100mg L-1. A biomassa foi produzida a partir de uma cultura "starter"de Saccharomyces cerevisiae IZ 1904. Após o contato de 16h entre o microrganismo e as soluções em estudo, a biomassa foi separada por centrifugação e o teor de cádmio residual foi determinado no sobrenadante por espectrofotometria de absorção atômica. Para os dois sais empregados foi observado um acúmulo crescente de cádmio nas concentrações de 5, 10, 20 e 40mg L-1. Nas concentrações de 60, 80 e 100mg L-1 foi observado que a levedura acumulou teores menores do metal, evidenciando danos na parede celular, nem sempre acompanhados de iguais danos da membrana citoplasmática, tais alterações da parede visualizadas por microscopia eletrônica de varredura.

ALBERTINI Silvana

2001-01-01

150

Saccharomyces cerevisiae: a versatile eukaryotic system in virology  

Directory of Open Access Journals (Sweden)

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.

Breinig Tanja

2007-10-01

151

Transcriptional Induction by Aromatic Amino Acids in Saccharomyces cerevisiae  

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Aromatic aminotransferase II, product of the ARO9 gene, catalyzes the first step of tryptophan, phenylalanine, and tyrosine catabolism in Saccharomyces cerevisiae. ARO9 expression is under the dual control of specific induction and nitrogen source regulation. We have here identified UASaro, a 36-bp upstream element necessary and sufficient to promote transcriptional induction of reporter gene expression in response to tryptophan, phenylalanine, or tyrosine. We then isolated mutants in which U...

Iraqui, Ismai?l; Vissers, Ste?phan; Andre?, Bruno; Urrestarazu, Antonio

1999-01-01

152

Control of mitochondrial gene expression in the yeast Saccharomyces cerevisiae.  

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Mitochondrial promoters in Saccharomyces cerevisiae contain an identical octanucleotide [sequence: see text] sequence present just upstream of the initiation site (at the left end of the arrow). Studies have shown that the transcription rates of mitochondrial genes vary from 7- to 15-fold. The nucleotide at position +2 regulates the efficiency of mitochondrial promoters but does not affect the specificity of initiation. The data presented herein demonstrate that the variable transcription rat...

Biswas, T. K.

1990-01-01

153

Nutritional Control via Tor signaling in Saccharomyces cerevisiae  

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The yeast Saccharomyces cerevisiae senses and responds to nutrients by adapting its growth rate and undergoing morphogenic transitions to ensure survival. The Tor pathway is a major integrator of nutrient-derived signals that in coordination with other signaling pathways orchestrates cell growth. Recent advances have identified novel Tor kinase substrates and established the protein trafficking membranous network and the nucleus as platforms for Tor signaling. These and other recent findings ...

Rohde, John R.; Bastidas, Robert; Puria, Rekha; Cardenas, Maria E.

2008-01-01

154

ACÚMULO DE CÁDMIO POR Saccharomyces cerevisiae FERMENTANDO MOSTO DE MELAÇO  

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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 contamina?...

Do, Prado-filho L. G.; Domingos, R. N.; Da, Silva S. M. G.

1998-01-01

155

Magnetically altered ethanol fermentation capacity of Saccharomyces cerevisiae  

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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...

Galonja-Corghill Tamara; Kostadinovi? Ljiljana M.; Bojat Nenad C.

2009-01-01

156

Alcoholic fermentation of lactose by engineered flocculent Saccharomyces cerevisiae  

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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 ...

Guimara?es, Pedro M. R.; Teixeira, J. A.; Domingues, Luci?lia

2008-01-01

157

Tunicamycin inhibition of epispore formation in Saccharomyces cerevisiae.  

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The ascopore wall of Saccharomyces cerevisiae was found to contain more protein, polymeric glucosamine, and beta-glucan than the vegetative cell wall, which was enriched in mannoprotein relative to ascospore walls. Tunicamycin inhibited sporulation, as judged by the absence of refractile ascospores visible by phase-contrast microscopy, but cells completed meiosis, as demonstrated by the presence of multinucleate asci. Such spores lacked the dense outer layer characteristic of normal spores. T...

Weinstock, K. G.; Ballou, C. E.

1987-01-01

158

The mannoprotein of Saccharomyces cerevisiae is an effective bioemulsifier.  

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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...

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

1988-01-01

159

Genetic Basis of Mitochondrial Function and Morphology in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The understanding of the processes underlying organellar function and inheritance requires the identification and characterization of the molecular components involved. We pursued a genomic approach to define the complements of genes required for respiratory growth and inheritance of mitochondria with normal morphology in yeast. With the systematic screening of a deletion mutant library covering the nonessential genes of Saccharomyces cerevisiae the numbers of genes known to be required for r...

Dimmer, Kai Stefan; Fritz, Stefan; Fuchs, Florian; Messerschmitt, Marlies; Weinbach, Nadja; Neupert, Walter; Westermann, Benedikt

2002-01-01

160

Characterization of Saccharomyces cerevisiae mutants supersensitive to aminoglycoside antibiotics.  

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We describe mutants of Saccharomyces cerevisiae that are more sensitive than the wild type to the aminoglycoside antibiotics G418, hygromycin B, destomycin A, and gentamicin X2. In addition, the mutants are sensitive to apramycin, kanamycin B, lividomycin A, neamine, neomycin, paromomycin, and tobramycin--antibiotics which do not inhibit wild-type strains. Mapping studies suggest that supersensitivity is caused by mutations in at least three genes, denoted AGS1, AGS2, and AGS3 (for aminoglyco...

Ernst, J. F.; Chan, R. K.

1985-01-01

 
 
 
 
161

Overproduction of threonine by Saccharomyces cerevisiae mutants resistant to hydroxynorvaline.  

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In this work, we isolated and characterized mutants that overproduce threonine from Saccharomyces cerevisiae. The mutants were selected for resistance to the threonine analog alpha-amino-beta-hydroxynorvalerate (hydroxynorvaline), and, of these, the ones able to excrete threonine to the medium were chosen. The mutant strains produce between 15 and 30 times more threonine than the wild type does, and, to a lesser degree, they also accumulate isoleucine. Genetic and biochemical studies have rev...

Ramos, C.; Calderon, I. L.

1992-01-01

162

Chromatin remodeling during Saccharomyces cerevisiae ADH2 gene activation.  

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We have analyzed at both low and high resolution the distribution of nucleosomes over the Saccharomyces cerevisiae ADH2 promoter region in its chromosomal location, both under repressing (high-glucose) conditions and during derepression. Enzymatic treatments (micrococcal nuclease and restriction endonucleases) were used to probe the in vivo chromatin structure during ADH2 gene activation. Under glucose-repressed conditions, the ADH2 promoter was bound by a precise array of nucleosomes, the pr...

Verdone, L.; Camilloni, G.; Di Mauro, E.; Caserta, M.

1996-01-01

163

Homeostatic and Adaptive Responses to Zinc Deficiency in Saccharomyces cerevisiae*  

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Zinc is an essential nutrient and serves as a structural or catalytic cofactor for many proteins. Thus, cells need mechanisms to maintain zinc homeostasis when available zinc supplies decrease. In addition, cells require other mechanisms to adapt intracellular processes to suboptimal levels of zinc. By exploring the transcriptional responses to zinc deficiency, studies of the yeast Saccharomyces cerevisiae have revealed both homeostatic and adaptive responses to low zinc. The Zap1 zinc-respon...

Eide, David J.

2009-01-01

164

The enantioselective b-keto ester reductions by Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available The enantioselective yeast reduction of aromatic b-keto esters, by use of potassium dihydrogen phosphate, calcium phosphate (monobasic, magnesium sulfate and ammonium tartrate (diammonium salt (10:1:1:50 in water at pH 7 as a buffer for 72–120 h with 45–90 % conversion to the corresponding aromatic -hydroxy esters was achieved by means of Saccharomyces cerevisiae.

HASSAN TAJIK

2006-09-01

165

Biogeographical characterization of Saccharomyces cerevisiae wine yeast by molecular methods  

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Biogeography is the descriptive and explanatory study of spatial patterns and processes involved in the distribution of biodiversity. Without biogeography, it would be difficult to study the diversity of microorganisms because there would be no way to visualize patterns in variation. Saccharomyces cerevisiae, “the wine yeast,” is the most important species involved in alcoholic fermentation, and in vineyard ecosystems, it follows the principle of “everything is everywhere.” Agricultur...

Tofalo, Rosanna; Perpetuini, Giorgia; Schirone, Maria; Fasoli, Giuseppe; Aguzzi, Irene; Corsetti, Aldo; Suzzi, Giovanna

2013-01-01

166

Biogeographical characterisation of Saccharomyces cerevisiae wine yeast by molecular methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biogeography is the descriptive and explanatory study of spatial patterns and processes involved in the distribution of biodiversity. Without biogeography, it would be difficult to study the diversity of microorganisms because there would be no way to visualise patterns in variation. Saccharomyces cerevisiae, “the wine yeast”, is the most important species involved in alcoholic fermentation, and in vineyard ecosystems, it follows the principle of “everything is everywhere”. Agricultur...

RosannaTofalo

2013-01-01

167

Biogenesis of the Saccharomyces cerevisiae Mating Pheromone a-Factor  

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The Saccharomyces cerevisiae mating pheromone a-factor is a prenylated and carboxyl methylated extracellular peptide signaling molecule. Biogenesis of the a-factor precursor proceeds via a distinctive multistep pathway that involves COOH-terminal modification, NH2-terminal proteolysis, and a nonclassical export mechanism. In this study, we examine the formation and fate of a-factor biosynthetic intermediates to more precisely define the events that occur during a-factor biogenesis. We have...

Chen, Peng; Sapperstein, Stephanie K.; Choi, Jonathan D.; Michaelis, Susan

1997-01-01

168

Calcium dependence of Eugenol tolerance and toxicity in Saccharomyces cerevisiae  

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Eugenol is a plant-derived phenolic compound which has recognised therapeutical potential as an antifungal agent. However little is known of either its fungicidal activity or the mechanisms employed by fungi to tolerate eugenol toxicity. A better exploitation of eugenol as a therapeutic agent will therefore depend on addressing this knowledge gap. Eugenol initiates increases in cytosolic Ca2+ in Saccharomyces cerevisiae which is partly dependent on the plasma membrane calcium channel, Cch1p. ...

Roberts, Stephen; Mcainsh, Martin; Cantopher, Hanna; Sandison, Sean

2014-01-01

169

Molecular Analysis of Maltotriose Transport and Utilization by Saccharomyces cerevisiae  

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Efficient fermentation of maltotriose is a desired property of Saccharomyces cerevisiae for brewing. In a standard wort, maltotriose is the second most abundant sugar, and slower uptake leads to residual maltotriose in the finished product. The limiting factor of sugar metabolism is its transport, and there are conflicting reports on whether a specific maltotriose permease exists or whether the mechanisms responsible for maltose uptake also carry out maltotriose transport. In this study, radi...

Day, Rachel E.; Rogers, Peter J.; Dawes, Ian W.; Higgins, Vincent J.

2002-01-01

170

Arsenic oxide-induced thermotolerance in Saccharomyces cerevisiae.  

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The growth response of Saccharomyces cerevisiae to arsenite and arsenate and the relationship between the enhancement of heat shock protein (hsp) synthesis caused by these arsenic oxides and thermotolerance are reported. Arsenite and arsenate transiently inhibited cell growth and overall protein synthesis; arsenate enhanced the synthesis of the 42-, 74-, 84-, and 100-kilodalton hsps, whereas arsenite enhanced synthesis of only the 74-kilodalton hsp. The induction of these hsps reached a maxim...

Chang, E. C.; Kosman, D. J.; Willsky, G. R.

1989-01-01

171

Cr(III) removal and recovery from Saccharomyces cerevisiae  

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Heavy metal recovery from biosorbents is of major importance in the assessment of competitiveness of biosorption processes. Several desorption agents (H2SO4, HNO3, HCl, CH3COOH and EDTA) were tested for the selection of the optimal elution conditions for Cr(III) recovery from Saccharomyces cerevisiae cells. Sorption time was optimised as it plays an important role in the sorption–desorption process, being shown that a 30 min sorption period is the best option to ensure metal rem...

Ferraz, A. I.; Tavares, M. T.; Teixeira, J. A.

2004-01-01

172

Isolation and characterization of a Saccharomyces cerevisiae peptide transport gene.  

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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...

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

1994-01-01

173

Engineered Saccharomyces cerevisiae capable of simultaneous cellobiose and xylose fermentation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of plant biomass for biofuel production will require efficient utilization of the sugars in lignocellulose, primarily glucose and xylose. However, strains of Saccharomyces cerevisiae presently used in bioethanol production ferment glucose but not xylose. Yeasts engineered to ferment xylose do so slowly, and cannot utilize xylose until glucose is completely consumed. To overcome these bottlenecks, we engineered yeasts to coferment mixtures of xylose and cellobiose. In these yeast strai...

Ha, Suk-jin; Galazka, Jonathan M.; Rin Kim, Soo; Choi, Jin-ho; Yang, Xiaomin; Seo, Jin-ho; Louise Glass, N.; Cate, Jamie H. D.; Jin, Yong-su

2011-01-01

174

Intracellular ethanol accumulation in Saccharomyces cerevisiae during fermentation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An intracellular accumulation of ethanol in Saccharomyces cerevisiae was observed during the early stages of fermentation (3 h). However, after 12 h of fermentation, the intracellular and extracellular ethanol concentrations were similar. Increasing the osmotic pressure of the medium caused an increase in the ratio of intracellular to extracellular ethanol concentrations at 3 h of fermentation. As in the previous case, the intracellular and extracellular ethanol concentrations were similar af...

D Amore, T.; Panchal, C. J.; Stewart, G. G.

1988-01-01

175

Cloning and heterologous expression of glycosidase genes from Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Genomic clones were isolated that code for three glycosidases proposed to be involved in the catabolism of cell wall components in Saccharomyces cerevisiae. alpha-Mannosidase (AMS1), exoglucanase (BGL1), and endochitinase (CTS1) genes were isolated with the aid of filter assays based on the hydrolysis of 4-methylumbelliferyl glycosides, which permitted the in situ monitoring of these glycosidase activities in yeast colonies. Uracil prototrophs resulting from transformation with a multicopy YE...

Kuranda, M. J.; Robbins, P. W.

1987-01-01

176

Lipid particle variants from the yeast saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In yeast as in most other cells neutral lipids TAG (triacylglycerols) and SE (steryl esters) are stored in subcellular fractions called lipid particles. In Saccharomyces cerevisiae, TAG and SE serve as a depot of building blocks for the formation of membranes. Major enzymes catalyzing synthesis of these neutral lipids, namely the TAG synthases Dga1p and Lro1p, and the steryl ester synthases Are1p and Are2p, have been identified and partially characterized. However, detaile...

Czabany, Tibor; Wagner, A.; Zweytick, D.; Ingolic, E.; Spanova, M.; Hapala, Ivan; Daum, Gu?nther

2007-01-01

177

In vivo rearrangement of mitochondrial DNA in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A revertant (SPR1) from a high-frequency petite strain of Saccharomyces cerevisiae has been shown by mapping and sequence analysis to have a rearranged mitochondrial genome. In vivo rearrangement has occurred through a subgenomic-recombination pathway involving the initial formation of subgenomic molecules in nascent petite mutants, recombination between these molecules to form an intermediate with direct repeats, and subsequent excision of the resident or symposed duplication to yield a mole...

Clark-walker, G. D.

1989-01-01

178

Genetic Analysis of Desiccation Tolerance in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Desiccation tolerance, the ability to survive nearly total dehydration, is a rare strategy for survival and reproduction observed in all taxa. However, the mechanism and regulation of this phenomenon are poorly understood. Correlations between desiccation tolerance and potential effectors have been reported in many species, but their physiological significance has not been established in vivo. Although the budding yeast Saccharomyces cerevisiae exhibits extreme desiccation tolerance, its usef...

Calahan, Dean; Dunham, Maitreya; Desevo, Chris; Koshland, Douglas E.

2011-01-01

179

Information propagation within the Genetic Network of Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background A gene network's capacity to process information, so as to bind past events to future actions, depends on its structure and logic. From previous and new microarray measurements in Saccharomyces cerevisiae following gene deletions and overexpressions, we identify a core gene regulatory network (GRN) of functional interactions between 328 genes and the transfer functions of each gene. Inferred connections are verified by gene enrichment. Resu...

Yli-Harja Olli; Hughes Timothy R; Cv, Baici Wayne; Smolander Olli-Pekka; Lloyd-Price Jason; Chowdhury Sharif; Chua Gordon; Ribeiro Andre S

2010-01-01

180

Construction of a flocculent saccharomyces cerevisiae fermenting lactose  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A flocculent Saccharomyces cerevisiae strain with the ability to express both the LAC4 (coding for b-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus was constructed. This recombinant strain is not only able to grow on lactose, but it can also ferment this substrate. To our knowledge this is the first time that a recombinant S. cervisiae has been found to ferment lactose in a way comparable to that of the existing lactose-fermenting ...

Domingues, Luci?lia; Teixeira, J. A.; Lima, Nelson

1999-01-01

 
 
 
 
181

The Snf1 Protein Kinase in the Yeast Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 s...

Usaite, Renata; Olsson, Lisbeth; Nielsen, Jens

2009-01-01

182

Global response of Saccharomyces cerevisiae to an alkylating agent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

DNA chip technology enables simultaneous examination of how ?6,200 Saccharomyces cerevisiae gene transcript levels, representing the entire genome, respond to environmental change. By using chips bearing oligonucleotide arrays, we show that, after exposure to the alkylating agent methyl methanesulfonate, ?325 gene transcript levels are increased and ?76 are decreased. Of the 21 genes that already were known to be induced by a DNA-damaging agent, 18 can be sco...

Jelinsky, Scott A.; Samson, Leona D.

1999-01-01

183

Engineering the Monomer Composition of Polyhydroxyalkanoates Synthesized in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polyhydroxyalkanoates (PHAs) have received considerable interest as renewable-resource-based, biodegradable, and biocompatible plastics with a wide range of potential applications. We have engineered the synthesis of PHA polymers composed of monomers ranging from 4 to 14 carbon atoms in either the cytosol or the peroxisome of Saccharomyces cerevisiae by harnessing intermediates of fatty acid metabolism. Cytosolic PHA production was supported by establishing in the cytosol critical ?-oxidatio...

Zhang, Bo; Carlson, Ross; Srienc, Friedrich

2006-01-01

184

Isolation and characterization of aminopeptidase mutants of Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mutants of Saccharomyces cerevisiae were isolated which have decreased ability to hydrolyze leucine beta-naphthylamide, a chromogenic substrate for amino-peptidases. The mutations were shown by starch gel electrophoresis to affect one of four different aminopeptidases. Mutations affecting a given enzyme belong to a single complementation group. The four genes were symbolized lap1, lap2, lap3, and lap4, and the corresponding enzymes LAPI, LAPII, LAPIII, and LAPIV. Both lap1 and lap4 were mappe...

Trumbly, R. J.; Bradley, G.

1983-01-01

185

Spontaneous loss of heterozygosity in diploid Saccharomyces cerevisiae cells.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To obtain a broad perspective of the events leading to spontaneous loss of heterozygosity (LOH), we have characterized the genetic alterations that functionally inactivated the URA3 marker hemizygously or heterozygously situated either on chromosome III or chromosome V in diploid Saccharomyces cerevisiae cells. Analysis of chromosome structure in a large number of LOH clones by pulsed-field gel electrophoresis and PCR showed that chromosome loss, allelic recombination, and chromosome aberrati...

Hiraoka, M.; Watanabe, K.; Umezu, K.; Maki, H.

2000-01-01

186

Nuclear Mitochondrial DNA Activates Replication in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The nuclear genome of eukaryotes is colonized by DNA fragments of mitochondrial origin, called NUMTs. These insertions have been associated with a variety of germ-line diseases in humans. The significance of this uptake of potentially dangerous sequences into the nuclear genome is unclear. Here we provide functional evidence that sequences of mitochondrial origin promote nuclear DNA replication in Saccharomyces cerevisiae. We show that NUMTs are rich in key autonomously replicating sequence (...

Chatre, Laurent; Ricchetti, Miria

2011-01-01

187

Regulatory mutations affecting ornithine decarboxylase activity in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We isolated several strains of Saccharomyces cerevisiae containing mutations mapping at a single chromosomal gene (spe10); these strains are defective in the decarboxylation of L-ornithine to form putrescine and consequently do not synthesize spermidine and spermine. The growth of one of these mutants was completely eliminated in a polyamine-deficient medium; the growth rate was restored to normal if putrescine, spermidine, or spermine was added. spe10 is not linked to spe2 (adenosylmethionin...

Cohn, M. S.; Tabor, C. W.; Tabor, H.

1980-01-01

188

An apoptotic cell cycle mutant in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

Villadsen, Ingrid

1996-01-01

189

Highly efficient assimilation of lactose by a metabolically engineered strain of Saccharomyces cerevisiae.  

Science.gov (United States)

A diploid strain of Saccharomyces cerevisiae able to metabolize lactose with high efficiency has been obtained. Haploid strains of Saccharomyces able to grow on lactose were constructed by cotransformation with two genes of Kluyveromyces lactis required for the utilization of the sugar, LAC4 and LAC12, encoding beta-galactosidase and lactose permease respectively. Both genes were placed under the control of a galactose-inducible promoter and targeted to the rDNA encoding region (RDN1 locus) of the Saccharomyces genome. Lac+ transformants were selected on medium with lactose as the only carbon source. These transformants were mitotically stable, they maintained the Lac+ phenotype after growing in non-selective medium for more than 60 generations, but their growth was slow. We found that this lack of vigour was caused by their genetic background and not by a deficient expression of the heterologous genes. Therefore, their performance could be improved by crossing with a wild-type strain. Among the offspring of the crosses, two strains of opposite mating type were selected and mated to obtain a fast-growing Lac+ diploid. This diploid strain showed the typical fermentative behaviour of S. cerevisiae when it was grown in aerated liquid medium with glucose. In lactose medium, it exhibited a respiro-fermentative metabolism similar to that of K. lactis, with low ethanol production and high biomass yield. PMID:9818720

Rubio-Texeira, M; Castrillo, J I; Adam, A C; Ugalde, U O; Polaina, J

1998-06-30

190

Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation.  

Science.gov (United States)

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, particularly involving the expression of the lactose genes of the phylogenetically related yeast Kluyveromyces lactis, but also the lactose genes from Escherichia coli and Aspergillus niger, as reviewed here. Due to the existing large amounts of whey, the production of bio-ethanol from lactose by engineered S. cerevisiae has been considered as a possible route for whey surplus. Emphasis is given in the present review on strain improvement for lactose-to-ethanol bioprocesses, namely flocculent yeast strains for continuous high-cell-density systems with enhanced ethanol productivity. PMID:21326922

Domingues, Lucília; Guimarães, Pedro M R; Oliveira, Carla

2010-01-01

191

A Saccharomyces cerevisiae-based bioassay for assessing pesticide toxicity.  

Science.gov (United States)

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

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

2009-12-01

192

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish 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.

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

2003-01-01

193

MAPKs regulate mitophagy in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The autophagy-dependent selective degradation of mitochondria (mitophagy) plays an important role in removing excessive, damaged and dysfunctional mitochondria to maintain a proper cellular homeostasis. Relative to its significance in cell physiology, very little is known about the molecular machinery and regulatory mechanism of mitophagy in mammalian cells or yeast. We found that two mitogen-activated protein kinases (MAPKs), Slt2 and Hog1, are required for mitophagy in Saccharomyces cerevis...

Mao, Kai; Klionsky, Daniel J.

2011-01-01

194

Fermentation capacity of Saccharomyces cerevisiae cultures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work aimed at the assessment of fermentative capacity of original diploid, monocellular haploid and recuperated diploid cultures of S. cerevisiae in sterilized sugar-cane wort. Twenty eight cultures were analyzed, four being original diploids (URM-4420, Itaiquara Ferment FIT, Lallemand Ferment FLA and Wild Ferment SEL); 12 monocellular haploids from original ones and 12 recuperated diploids from the monocells. The ethanol percentage ranged from 1.7 to 6.2% and the unfermentable reducing ...

Elvira Maria Bezerra de Alencar; Cristina Maria Souza-Motta; Bruno Souza Walter; Rejane Maria Pessoa Santos; Olga Martins Marques; Lusinete Aciole de Queiroz

2009-01-01

195

A conserved family of Saccharomyces cerevisiae synthases effects dihydrouridine modification of tRNA.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dihydrouridine modification of tRNA is widely observed in prokaryotes and eukaryotes, as well as in some archaea. In Saccharomyces cerevisiae every sequenced tRNA has at least one such modification, and all but one have two or more. We have used a biochemical genomics approach to identify the gene encoding dihydrouridine synthase 1 (Dus1, ORF YML080w), using yeast pre-tRNA(Phe) as a substrate. Dus1 is a member of a widespread family of conserved proteins, three other members of which are foun...

Xing, Feng; Martzen, Mark R.; Phizicky, Eric M.

2002-01-01

196

Role of UME6 in transcriptional regulation of a DNA repair gene in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Saccharomyces cerevisiae UV radiation and a variety of chemical DNA-damaging agents induce the transcription of specific genes, including several involved in DNA repair. One of the best characterized of these genes is PHR1, which encodes the apoenzyme for DNA photolyase. Basal-level and damage-induced expression of PHR1 require an upstream activation sequence, UAS(PHR1), which has homology with DRC elements found upstream of at least 19 other DNA repair and DNA metabolism genes in yeast. H...

Sweet, D. H.; Jang, Y. K.; Sancar, G. B.

1997-01-01

197

Synthetic lethal interactions suggest a role for the Saccharomyces cerevisiae Rtf1 protein in transcription elongation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Strong evidence indicates that transcription elongation by RNA polymerase II (pol II) is a highly regulated process. Here we present genetic results that indicate a role for the Saccharomyces cerevisiae Rtf1 protein in transcription elongation. A screen for synthetic lethal mutations was carried out with an rtf1 deletion mutation to identify factors that interact with Rtf1 or regulate the same process as Rtf1. The screen uncovered mutations in SRB5, CTK1, FCP1, and POB3. These genes encode an...

Costa, P. J.; Arndt, K. M.

2000-01-01

198

Saccharomyces cerevisiae Ribosomal Protein L26 Is Not Essential for Ribosome Assembly and Function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ribosomal proteins play important roles in ribosome biogenesis and function. Here, we study the evolutionarily conserved L26 in Saccharomyces cerevisiae, which assembles into pre-60S ribosomal particles in the nucle(ol)us. Yeast L26 is one of the many ribosomal proteins encoded by two functional genes. We have disrupted both genes; surprisingly, the growth of the resulting rpl26 null mutant is apparently identical to that of the isogenic wild-type strain. The absence of L26 minimally alters 6...

Babiano, Reyes; Gamalinda, Michael; Woolford, John L.; La Cruz, Jesu?s

2012-01-01

199

Characteristics of Fps1-dependent and -independent glycerol transport in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Eadie-Hofstee plots of glycerol uptake in wild-type Saccharomyces cerevisiae W303-1A grown on glucose showed the presence of both saturable transport and simple diffusion, whereas an fps1delta mutant displayed only simple diffusion. Transformation of the fps1delta mutant with the glpF gene, which encodes glycerol transport in Escherichia coli, restored biphasic transport kinetics. Yeast extract-peptone-dextrose-grown wild-type cells had a higher passive diffusion constant than the fps1delta m...

Sutherland, F. C.; Lages, F.; Lucas, C.; Luyten, K.; Albertyn, J.; Hohmann, S.; Prior, B. A.; Kilian, S. G.

1997-01-01

200

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 contai...

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

1993-01-01

 
 
 
 
201

Tryptophan Permease Gene TAT2 Confers High-Pressure Growth in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hydrostatic pressure in the range of 15 to 25 MPa was found to cause arrest of the cell cycle in G1 phase in an exponentially growing culture of Saccharomyces cerevisiae, whereas a pressure of 50 MPa did not. We found that a plasmid carrying the TAT2 gene, which encodes a high-affinity tryptophan permease, enabled the cells to grow under conditions of pressure in the range of 15 to 25 MPa. Additionally, cells expressing the Tat2 protein at high levels became endowed with the ability to grow u...

Abe, Fumiyoshi; Horikoshi, Koki

2000-01-01

202

Multiple-drug-resistance phenomenon in the yeast Saccharomyces cerevisiae: involvement of two hexose transporters.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the yeast Saccharomyces cerevisiae, multidrug resistance to unrelated chemicals can result from overexpression of ATP-binding cassette (ABC) transporters such as Pdr5p, Snq2p, and Yor1p. Expression of these genes is under the control of two homologous zinc finger-containing transcription regulators, Pdr1p and Pdr3p. Here, we describe the isolation, by an in vivo screen, of two new Pdr1p-Pdr3p target genes: HXT11 and HXT9. HXT11 and HXT9, encoding nearly identical proteins, have a high degr...

Nourani, A.; Wesolowski-louvel, M.; Delaveau, T.; Jacq, C.; Delahodde, A.

1997-01-01

203

N myristylation of the human immunodeficiency virus type 1 gag polyprotein precursor in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

A semisynthetic gene precisely encoding the 502 amino acids of the human immunodeficiency virus type 1 gag precursor (Pr53gag) was expressed in the yeast Saccharomyces cerevisiae. Amino acid sequence analysis of the recombinant Pr53gag showed that the amino terminus was fully blocked. Labeling of Pr53gag with [3H]myristic acid demonstrated that, as with Pr53gag isolated from virus-infected cells, the yeast-derived protein was demethionylated and N myristylated on glycine, the second amino acid residue

204

Studio dell'aggregazione cellulare in ceppi vinari di Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Among the different genes that regulate biofilm formation in strains of Saccharomyces cerevisiae, FLO11 plays a fundamental role. In a previous work we showed that FLO11 is required for air-liquid interfacial biofilm and we proposed a model for biofilm formation based on the ability of cells to entrap carbon dioxide, providing buoyancy. FLO11 belongs to the adhesin gene family, including FLO1, FLO5, FLO9 and FLO10 and the protein encoded by each gene has considerable sequence identity with ot...

Pinna, Claudia -.

2009-01-01

205

Isolation and characterization of mutations in the HXK2 gene of Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several hundred new mutations in the gene (HXK2) encoding hexokinase II of Saccharomyces cerevisiae were isolated, and a subset of them was mapped, resulting in a fine-structure genetic map. Among the mutations that were sequenced, 35 were independent missense mutations. The mutations were obtained by mutagenesis of cloned HXK2 DNA carried on a low-copy-number plasmid vector and screened for a number of different phenotypes in yeast strains bearing chromosomal hxk1 and hxk2 null mutations. So...

Ma, H.; Bloom, L. M.; Zhu, Z. M.; Walsh, C. T.; Botstein, D.

1989-01-01

206

Daughter-specific repression of Saccharomyces cerevisiae HO: Ash1 is the commander  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The GATA-1-like factor Ash1 is a repressor of the HO gene, which encodes an endonuclease that is responsible for mating-type switching in the yeast Saccharomyces cerevisiae. A multi-step programme, which involves a macromolecular protein complex, the secondary structure of ASH1 mRNA and the cell cytoskeleton, enables Ash1 to asymmetrically localize to the daughter cell nucleus in late anaphase and to repress HO transcription. The resulting Ash1 activity prevents the daughter cell from switchi...

Cosma, Maria Pia

2004-01-01

207

Nucleotide sequence and promoter analysis of SPO13, a meiosis-specific gene of Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The SPO13 gene, required for meiosis I segregation in Saccharomyces cerevisiae, produces two developmentally regulated transcripts (1.0 and 1.4 kilobases) that differ in length at their 5' ends. The shorter transcript is sufficient to complement the spo13-1 mutation and contains a major open reading frame encoding a highly basic protein of 33.4 kilodaltons. A fragment upstream (-170 to -8) of the open reading frame confers meiosis-specific transcription on a spo13-HIS3 fusion. Deletions at th...

Buckingham, L. E.; Wang, H. T.; Elder, R. T.; Mccarroll, R. M.; Slater, M. R.; Esposito, R. E.

1990-01-01

208

Bioconversion of heptanal to heptanol by Saccharomyces cerevisiae.  

Science.gov (United States)

Saccharomyces cerevisiae is widely known for its catalytic activity on substrates such as aldehyde and ketone. Interestingly, the activity of S. cerevisiae on heptanal (C(6)H(13)CHO), in spite of its being a very common aldehyde, has not been explored. The main objective of this study was therefore to investigate the bioconversion of heptanal, using a strain of the yeast S. cerevisiae. Bioconversion parameters such as incubation period, pH, concentration of substrate, yeast and maltose were also optimized. The study revealed heptanol as the major product. The optimum conditions for biotransformation were found to be: 3 days incubation; pH 7.0; heptanal concentration 0.15 ml/100 ml medium; and S. cerevisiae concentration of 0.15 g/100 ml medium. Reduction in maltose content (to 0.3 g maltose/100 ml medium) showed increased conversion of heptanal. Heptanoic acid and 2-hydroxyheptanoic acid were obtained as two minor co-products. The overall study showed that S. cerevisiae converted heptanal to heptanol by a yield of 68.9 +/- 1.1% w/w under optimum conditions. PMID:20120041

Verma, Shikha; Ray, Aurobindo Kumar; De, Bijay Krishna

2010-05-01

209

GPI lipid remodeling in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The lipid moieties of mature GPI anchors of S. cerevisiae usually do not contain the diacylglycerol present on CP2, the mature GPI lipid transferred by the GPI transamidase to proteins in the ER. CP2 probably contains the C16 and C18:1 fatty acids found in regular yeast PI, whereas most mature GPI proteins of yeast contain a ceramide moiety, and a minor fraction contains a modified diacylglycerol containing C26:0 in sn2. Recent studies have identified Per1p and Gup1p as be...

Conzelmann, Andreas; Pagac, Martin; Jaquenoud, Malika; Bosson, Re?gine; Ghugtyal, Vikram; Roubaty, Carole; Vionnet, Christine

2007-01-01

210

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)

211

Deletion of the GRE3 Aldose Reductase Gene and Its Influence on Xylose Metabolism in Recombinant Strains of Saccharomyces cerevisiae Expressing the xylA and XKS1 Genes  

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Saccharomyces cerevisiae ferments hexoses efficiently but is unable to ferment xylose. When the bacterial enzyme xylose isomerase (XI) from Thermus thermophilus was produced in S. cerevisiae, xylose utilization and ethanol formation were demonstrated. In addition, xylitol and acetate were formed. An unspecific aldose reductase (AR) capable of reducing xylose to xylitol has been identified in S. cerevisiae. The GRE3 gene, encoding the AR enzyme, was deleted in S. cerevisiae CEN.PK2-1C, yieldin...

Tra?ff, K. L.; Otero Cordero, R. R.; Zyl, W. H.; Hahn-ha?gerdal, B.

2001-01-01

212

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)

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-acetylpyridine-NAD(+) by NADPH and by NADH in the presence of NADP(+), which demonstrated that an active enzyme was present. Unlike the situation in E. coli, however, most of the transhydrogenase activity was not present in the yeast plasma membrane; rather, the enzyme appeared to remain localized in the membrane of the endoplasmic reticulum. During anaerobic glucose fermentation we observed an increase in the formation of 2-oxoglutarate, glycerol, and acetic acid in a strain expressing a high level of transhydrogenase, which indicated that increased NADPH consumption and NADH production occurred. The intracellular concentrations of NADH, NAD(+) NADPH, and NADP(+) were measured in cells expressing transhydrogenase. The reduction of the NADPH pool indicated that the transhydrogenase transferred reducing equivalents from NADPH to NAD(+).

Anderlund, M.; Nissen, Torben Lauesgaard

1999-01-01

213

Ultradian oscillators of the circadian clock in Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available The yeast, Saccharomyces cerevisiae, has an ENOX1 activity with a period length of 24 min similar to that of other eukaryotes. In contrast to other eukaryotes, however, Saccharomyces cerevisiae has a second ENOX1-like activity with a period length of 25 min. The latter is distinguishable from the traditional ENOX1 on the basis of the longer period length along with resistance to an ENOX1 inhibitor, simalikalactone D, and failure to be phased by melatonin. In addition, two periods are apparent in measurements of oxygen consumption indicating that the consumption of oxygen to water occurs independently by homodimers of both of the two forms of ENOX. Based on the measurements of glyceraldehyde-3- phosphate dehydrogenase, S. cerevisiae exhibits circadian activity maxima at 24 and 25 h together with a 40 h period possibly representing the 40 min metabolic rhythm of yeast not observed in our measurement of oxygen consumption and normally observed only with continuous cultures. The findings are indicative of at least three independent time-keeping systems being operative in a single cell. 

Sara S. Dick

2013-02-01

214

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

Directory of Open Access Journals (Sweden)

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.

Bijender K. Bajaj

2010-06-01

215

Cloning and DNA sequence analysis of the glucose transporter gene2 from Iranian Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Saccharomyces cerevisiae has 20 genes that encode hexose transporter proteins including HXT1 to HXT17, GAL2, SNF3 and RGT2. Among these gene families, seven genes (HXT1-HXT7 have important role in alcohol production. The aim of this study was the identification and isolation of HXT2 gene from Saccharomyces cerevisiae genome by PCR technique and cloning into vector containing suitable expression promoter in order to design expression vector as a basis to produce recombinant yeast by transformation.Materials and Methods: After designing specific oligonucleotides primers, fragment gene amplified by PCR. Gene HXT2 inserted into pTZ57R vector by restriction enzymes EcoRI and HindIII and T4 ligase. After transformation of pTZ57R/THXT2 into E.coli, plasmid recombinant analysis considered. The final further analysis by restriction enzymes digestion and software were evaluated.Results: HXT2 gene isolated from pTZ57R/THXT2 has correct size in agarose gel electrophoresis. Electrophoresis analysis showed that this gene has correct size on agarose gel. Software study showed that this gene encode proteins with 59.84 KDa molecular weight having 541 amino acids with isoelectric point 8.3.Conclusion: HXT2 gene by PCR optimization from saccharomyces cerevisiae was isolated and cloned into prokaryotic host. This is the first report of isolation and cloning of this gene by using genetic engineering technique in IRAN that can be used for cloning into suitable expression vector to improve alcohol fermentation yield.

Saleh Amiri

2012-12-01

216

Determinação de isotermas de adsorção de Saccharomyces cerevisiae empregando acetato e sulfato de cádmio Cadmium adsorption isotherms by Saccharomyces cerevisiae using cadmiun acetate and sulphate  

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Para determinar as isotermas de adsorção de cádmio por Saccharomyces cerevisiae, foram utilizados os sais acetato e sulfato de cádmio, nas concentrações de 5; 10; 20; 40; 60; 80 e 100 mg.L-1. A biomassa foi produzida a partir de uma cultura "starter" de Saccharomyces cerevisiae IZ 1904. Após o contato de 16 horas entre o microrganismo em estudo e as soluções teste, a biomassa foi separada por centrifugação e o teor de cádmio residual foi determinado por espectrofotometria de absor...

Silvana Albertini; Leandro Francisco do Carmo; Luiz Gonzaga do Prado Filho

2007-01-01

217

Genetiese manipulering van die gis Saccharomyces cerevisiae betreffende polisakkariedbenutting Genetiese manipulering van die gis Saccharomyces cerevisiae betreffende polisakkariedbenutting  

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Die gis Saccharomyces cerevisiae word wêreldwyd as die belangrikste kommersiële mikro-organisme bestempel en geniet sogenaamde ABAV-status (Algemeen Beskou As Veilig) weens dié gis se eeue lange verbintenis met voedselproduksie (bv. brood, wyn, bier, proteienaanvulling en geurstowwe).Die gis Saccharomyces cerevisiae word wêreldwyd as die belangrikste kommersiële mikro-organisme bestempel en geniet sogenaamde ABAV-status (Algemeen Beskou As Veilig) weens dié ...

Pretoruis, I. S.

1992-01-01

218

Genomic Screen for Vacuolar Protein Sorting Genes in Saccharomyces cerevisiaeD?  

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The biosynthetic sorting of hydrolases to the yeast vacuole involves transport along two distinct routes referred to as the carboxypeptidase Y and alkaline phosphatase pathways. To identify genes involved in sorting to the vacuole, we conducted a genome-wide screen of 4653 homozygous diploid gene deletion strains of Saccharomyces cerevisiae for missorting of carboxypeptidase Y. We identified 146 mutant strains that secreted strong-to-moderate levels of carboxypeptidase Y. Of these, only 53 of...

Bonangelino, Cecilia J.; Chavez, Edna M.; Bonifacino, Juan S.

2002-01-01

219

A new disruption vector (pDHO) to obtain heterothallic strains from both Saccharomyces cerevisiae and Saccharomyces pastorianus  

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Yeasts are responsible for several traits in fermented beverages, including wine and beer, and their genetic manipulation is often necessary to improve the quality of the fermentation product. Improvement of wild-type strains of Saccharomyces cerevisiae and Saccharomyces pastorianus is difficult due to their homothallic character and variable ploidy level. Homothallism is determined by the HO gene in S. cerevisiae and the Sc-HO gene in S. pastorianus. In this work, we describe the constructio...

Blasco, Luci?a; Veiga Crespo, Patricia; Vin?as, Miquel; Villa, Toma?s G.

2011-01-01

220

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

 
 
 
 
221

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 ex show that the yeast cells exposed to U express several specific proteins. (author)

222

Applied systems biology - vanillin production in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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 vanillin produced in this S. cerevisiae strain is insufficient for commercial production and improvements need to be done. We have introduced the genes necessary for vanillin production in an identical manner in two different yeast strains S288c and CEN.PK,where comprehensive – omics datasets are available, hence, allowing vanillin production in the two strain backgrounds to be evaluated and compared in a systems biology setting.

Strucko, Tomas; Eriksen, Carsten

2012-01-01

223

Glucose- and nitrogen sensing and regulatory mechanisms in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

RØdkaer, Steven V; Færgeman, Nils J.

2014-01-01

224

Effect of environmental stress on radiation response of Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

We have investigated the effect of pH shock and oxidative stress (H2O2 effect) both separately and together on the response of Saccharomyces cerevisiae exposed to UV and gamma radiations for one hour. Exposure to these environmental stresses resulted in S. cerevisiae cells acquiring resistance to UV radiation. Presence of cycloheximide (a know protein synthesis inhibitor) during stress inhibited the acquired UV resistance. The increased UV resistance is apparently mediated through nucleotide excision repair as the stress exposure to rad3 mutants (defective in nucleotide excision repair) do not have any effect on UV response. Both types of stresses used probably follow the same path of induction of radioresistance as the effect of both of them is nonadditive. In the strains used in our study stress exposure dose not have any significant effect on gamma radiation response. (author)

225

Use of Saccharomyces cerevisiae in radioactive waste treatment  

International Nuclear Information System (INIS)

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)

226

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

2014-03-01

227

accumulation and subcellular localisation of metal cations by saccharomyces cerevisiae  

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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...

Blackwell, Kevin J.

1998-01-01

228

Bioaccumulation of thorium and uranyl ions on Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

The efficiency of the yeast suspension of Saccharomyces cerevisiae was studied in the decontamination of radioactive residual waste waters and in the biological behavior of the levuric mass. The effect of reaction time on the amino acid content in the supernatant and on the concentration of radioactive ions was also investigated. The reaction of yeast with the toxic agent showed that the living matter behaves differently from the chemical components of the cell. The yeast had the tendency to aggregate in the presence of radioactive ions. (author)

229

Saccharomyces cerevisiae: a potential biosorbent for biosorption of uranium.  

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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...

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

2011-01-01

230

Expression of Heteropolymeric Ferritin Improves Iron Storage in Saccharomyces cerevisiae  

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Saccharomyces cerevisiae was engineered to express different amount of heavy (H)- and light (L)-chain subunits of human ferritin by using a low-copy integrative vector (YIp) and a high-copy episomal vector (YEp). In addition to pep4::HIS3 allele, the expression host strain was bred to have the selection markers leu2? and ura3? for YIplac128 and YEp352, respectively. The heterologous expression of phytase was used to determine the expression capability of the host strain. Expression in the...

Kim, Hye-jin; Kim, Hyang-mi; Kim, Ji-hye; Ryu, Kyeong-seon; Park, Seung-moon; Jahng, Kwang-yeup; Yang, Moon-sik; Kim, Dae-hyuk

2003-01-01

231

Magnetically altered ethanol fermentation capacity of Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

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.

Galonja-Corghill Tamara

2009-01-01

232

Calcium uptake during the cell cycle of Saccharomyces cerevisiae.  

Science.gov (United States)

Synchronous culture of the budding yeast Saccharomyces cerevisiae was obtained by sucrose density gradient selection with 90-100% of yeast synchronized by using the cells in the bottom. In these adult cells bud emergence is coincident with an increase in calcium uptake at 100 min of the culture, followed by a return to basal values which are maintained until the end of the first cell cycle of study. The phenothiazine derivatives, trifluoperazine and chlorpromazine inhibit bud emergence and trifluoperazine also increases calcium uptake. PMID:6350041

Saavedra-Molina, A; Villalobos, R; Borbolla, M

1983-08-22

233

Yeast Saccharomyces cerevisiae response to UV and gamma irradiation  

International Nuclear Information System (INIS)

The investigation of UV-C and ? radiation and the dose effect on budding yeast Saccharomyces cerevisiae cell vital regulation process including cell sensitivity analysis at different stages of the cell cycle was carried out. Detailed calculations of the deposited UV-C and ? radiation doses and analysis of secondary electrons produced by ? rays in the sample were done using the simulation code MCNPX. Viability of cells of the yeast strains with different activity of Ras proteins and cyclic adenosine monophosphate signal pathway after irradiation was chosen as the criterion of yeast sensitivity. Depending on their genetic background, yeast cells possessed different response to ionizing radiation. (author)

234

Identification of Genes Required for ?2 Repression in Saccharomyces Cerevisiae  

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Transcriptional repression of the a-specific genes in Saccharomyces cerevisiae ? cells involves the concerted action of several proteins. The homeodomain protein ?2, together with MCM1, recruits two general transcriptional repressors, SSN6 and TUP1, to the promoters of a-specific genes. SSN6 and TUP1 then mediate repression of the a-specific genes. SIN4, another general negative regulator, is required for this repression, but unlike tup1 or ssn6 deletions, sin4 deletions cause only partial ...

Wahi, M.; Johnson, A. D.

1995-01-01

235

Conservative Duplication of Spindle Poles during Meiosis in Saccharomyces cerevisiae  

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During sporulation in diploid Saccharomyces cerevisiae, spindle pole bodies acquire the so-called meiotic plaque, a prerequisite for spore formation. Mpc70p is a component of the meiotic plaque and is thus essential for spore formation. We show here that MPC70/mpc70 heterozygous strains most often produce two spores instead of four and that these spores are always nonsisters. In wild-type strains, Mpc70p localizes to all four spindle pole bodies, whereas in MPC70/mpc70 strains Mpc70p localize...

Wesp, Andreas; Prinz, Susanne; Fink, Gerald R.

2001-01-01

236

HOL1 mutations confer novel ion transport in Saccharomyces cerevisiae.  

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Saccharomyces cerevisiae histidine auxotrophs are unable to use L-histidinol as a source of histidine even when they have a functional histidinol dehydrogenase. Mutations in the hol1 gene permit growth of His- cells on histidinol by enhancing the ability of cells to take up histidinol from the medium. Second-site mutations linked to HOL1-1 further increase histidinol uptake. HOL1 double mutants and, to a lesser extent, HOL1-1 single mutants show hypersensitivity to specific cations added to t...

Gaber, R. F.; Kielland-brandt, M. C.; Fink, G. R.

1990-01-01

237

Characterization of RNA polymerase III transcription regulation in Saccharomyces cerevisiae  

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RNA polymerase III synthetizes many small untranslated RNA, including tRNA and 5S rRNA which are essential to cell growth. In this work, we took an interest in RNA polymerase III transcription regulation in the baker's yeast, Saccharomyces cerevisiae. We have detected Sub1 on all class III genes in vivo. We also observed that Sub1 is able to stimulate RNA polymerase III transcription which has been reconstituted in vitro with TFIIIB et TFIIIC recombinants factors and purified RNA polymerase I...

Tavenet, Arounie

2011-01-01

238

Nitrogen catabolite repression of asparaginase II in Saccharomyces cerevisiae.  

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The biosynthesis of asparaginase II in Saccharomyces cerevisiae is subject to strong catabolite repression by a variety of nitrogen compounds. In the present study, asparaginase II synthesis was examined in a wild-type yeast strain and in strains carrying gdhA, gdhCR, or gdhCS mutations. The following effects were observed: (i) In the wild-type strain, the biosynthesis of asparaginase II was strongly repressed when either 10 mM ammonium sulfate or various amino acids (10 mM) served as the sou...

Dunlop, P. C.; Meyer, G. M.; Roon, R. J.

1980-01-01

239

Suppression of nuclear oscillations in Saccharomyces cerevisiae expressing Glu tubulin  

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In most eukaryotic cells, the C-terminal amino acid of ?-tubulin is aromatic (Tyr in mammals and Phe in Saccharomyces cerevisiae) and is preceded by two glutamate residues. In mammals, the C-terminal Tyr of ?-tubulin is subject to cyclic removal from the peptide chain by a carboxypeptidase and readdition to the chain by a tubulin–Tyr ligase. There is evidence that tubulin–Tyr ligase suppression and the resulting accumulation of detyrosinated (Glu) tubulin favor tumor growth, both in ani...

Badin-larc?on, A. C.; Boscheron, C.; Soleilhac, J. M.; Piel, M.; Mann, C.; Denarier, E.; Fourest-lieuvin, A.; Lafaneche?re, L.; Bornens, M.; Job, D.

2004-01-01

240

d-Xylulose Fermentation to Ethanol by Saccharomyces cerevisiae  

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We used commercial bakers' yeast (Saccharomyces cerevisiae) to study the conversion of d-xylulose to ethanol in the presence of d-xylose. The rate of ethanol production increased with an increase in yeast cell density. The optimal temperature for d-xylulose fermentation was 35°C, and the optimal pH range was 4 to 6. The fermentation of d-xylulose by yeast resulted in the production of ethanol as the major product; small amounts of xylitol and glycerol were also produced. The production of xy...

Chiang, Lin-chang; Gong, Cheng-shung; Chen, Li-fu; Tsao, George T.

1981-01-01

 
 
 
 
241

Radioimmunoassay for yeast killer toxin from Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

A radioimmunoassay was developed for the K1 killer toxin from strain T158C/S14a of Saccharomyces cerevisiae. Iodine 125-labelled toxin was made to a specific activity of 100 ?Ci/mg of protein. Antibody to purified toxin was prepared in rabbits using toxin cross-linked to itself. These antibodies, partially purified by 50 percent ammonium sulfate precipitation and Sepharose CL-6B column chromatography, produced one precipitation band with killer toxin and bound 125I-labelled toxin in a radioimmunoassay. The antibody preparation also bound with the toxins from another K1 killer, A364A, and three chromosomal superkiller mutants derived from it. (auth)

242

Fermentation of whey and starch by transformed Saccharomyces cerevisiae cells.  

Science.gov (United States)

Among the main agro-industrial wastes, whey and starch are of prime importance. In previous work we showed that strains of Saccharomyces cerevisiae transformed with the episomal plasmid pM1 allow production of yeast biomass and ethanol from whey/lactose. Ethanol production from whey and derivatives has been improved in computer-controlled bioreactors, while fermentation studies showed that the composition of the medium greatly modulates the productivity (g ethanol produced/l in 1 h of fermentation). A yeast strain for the simultaneous utilization of lactose and starch has also been developed. Biotechnological perspectives are discussed. PMID:7576548

Compagno, C; Porro, D; Smeraldi, C; Ranzi, B M

1995-10-01

243

Isobutanol production from D-xylose by recombinant Saccharomyces cerevisiae.  

Science.gov (United States)

Simultaneous overexpression of an optimized, cytosolically localized valine biosynthesis pathway together with overexpression of xylose isomerase XylA from Clostridium phytofermentans, transaldolase Tal1 and xylulokinase Xks1 enabled recombinant Saccharomyces cerevisiae cells to complement the valine auxotrophy of ilv2,3,5 triple deletion mutants for growth on D-xylose as the sole carbon source. Moreover, after additional overexpression of ketoacid decarboxylase Aro10 and alcohol dehydrogenase Adh2, the cells were able to ferment D-xylose directly to isobutanol. PMID:23279585

Brat, Dawid; Boles, Eckhard

2013-03-01

244

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

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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...

Pak, Julia; Segall, Jacqueline

2002-01-01

245

NDT80 and the Meiotic Recombination Checkpoint Regulate Expression of Middle Sporulation-Specific Genes in Saccharomyces cerevisiae  

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Distinct classes of sporulation-specific genes are sequentially expressed during the process of spore formation in Saccharomyces cerevisiae. The transition from expression of early meiotic genes to expression of middle sporulation-specific genes occurs at about the time that cells exit from pachytene and form the meiosis I spindle. To identify genes encoding potential regulators of middle sporulation-specific gene expression, we screened for mutants that expressed early meiotic genes but fail...

Hepworth, Shelley R.; Friesen, Helena; Segall, Jacqueline

1998-01-01

246

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

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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 pr...

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

2005-01-01

247

A new class of histone H2A mutations in Saccharomyces cerevisiae causes specific transcriptional defects in vivo.  

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Nucleosomes have been shown to repress transcription both in vitro and in vivo. However, the mechanisms by which this repression is overcome are only beginning to be understood. Recent evidence suggests that in the yeast Saccharomyces cerevisiae, many transcriptional activators require the SNF/SWI complex to overcome chromatin-mediated repression. We have identified a new class of mutations in the histone H2A-encoding gene HTA1 that causes transcriptional defects at the SNF/SWI-dependent gene...

Hirschhorn, J. N.; Bortvin, A. L.; Ricupero-hovasse, S. L.; Winston, F.

1995-01-01

248

Guanidine hydrochloride blocks a critical step in the propagation of the prion-like determinant [PSI+] of Saccharomyces cerevisiae  

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The cytoplasmic heritable determinant [PSI+] of the yeast Saccharomyces cerevisiae reflects the prion-like properties of the chromosome-encoded protein Sup35p. This protein is known to be an essential eukaryote polypeptide release factor, namely eRF3. In a [PSI+] background, the prion conformer of Sup35p forms large oligomers, which results in the intracellular depletion of functional release factor and hence inefficient translation termination. We have investigated the process by which the [...

Eaglestone, Simon S.; Ruddock, Lloyd W.; Cox, Brian S.; Tuite, Mick F.

2000-01-01

249

Gene Dosage Effect of l-Proline Biosynthetic Enzymes on l-Proline Accumulation and Freeze Tolerance in Saccharomyces cerevisiae  

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We have previously reported that l-proline has cryoprotective activity in Saccharomyces cerevisiae. A freeze-tolerant mutant with l-proline accumulation was recently shown to carry an allele of the PRO1 gene encoding ?-glutamyl kinase, which resulted in a single amino acid substitution (Asp154Asn). Interestingly, this mutation enhanced the activities of ?-glutamyl kinase and ?-glutamyl phosphate reductase, both of which catalyze the first two steps of l-proline synthesis and which together...

Terao, Yukiyasu; Nakamori, Shigeru; Takagi, Hiroshi

2003-01-01

250

Homofermentative Lactate Production Cannot Sustain Anaerobic Growth of Engineered Saccharomyces cerevisiae: Possible Consequence of Energy-Dependent Lactate Export  

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Due to a growing market for the biodegradable and renewable polymer polylactic acid, the world demand for lactic acid is rapidly increasing. The tolerance of yeasts to low pH can benefit the process economy of lactic acid production by minimizing the need for neutralizing agents. Saccharomyces cerevisiae (CEN.PK background) was engineered to a homofermentative lactate-producing yeast via deletion of the three genes encoding pyruvate decarboxylase and the introduction of a heterologous lactate...

Maris, A. J.; Winkler, A. A.; Porro, D.; Dijken, J. P.; Pronk, J. T.

2004-01-01

251

Acquisition of the Ability To Assimilate Mannitol by Saccharomyces cerevisiae through Dysfunction of the General Corepressor Tup1-Cyc8.  

Science.gov (United States)

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

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

2015-01-01

252

Identification of the constitutive ultradian oscillator of the circadian clock (ENOX1 in Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available A yeast (Saccharomyces cerevisiae deletion library was screened based on NADH fluorescence using a 384 well plate assay and robotics to identify a yeast isolate lacking the 24 min periodic cell surface oxidase. The oxidase was shown previously to be a candidate ultradian oscillator of the yeast’s biological clock. The cDNA was cloned from a yeast overexpression library and the encoded protein was expressed in bacteria and characterized. Glyceraldehyde-3-phosphate dehydrogenase activity was used as the cellular circadian indicator. The identified gene was YML117W which encodes a ca 126 kDa putative RNA-binding protein. The candidate ENOX1 activity from yeast had functional characteristics similar to those of other constitutive ENOX1 proteins of eukaryotes exhibiting oscillating activities with a temperature independent period length of 24 min phased by melatonin and low frequency electromagnetic fields and susceptible to inhibition by the ENOX1 inhibitor, simalikalactone D. The YML117W deletion mutant cells lacked the ENOX1 clock output present in wild type yeast. The findings identify YML117W as the ENOX1 of Saccharomyces cerevisiae and support its proposed function as an ultradian oscillator of the yeast biological clock.

Sara S. Dick

2013-05-01

253

Nrg1 Is a Transcriptional Repressor for Glucose Repression of STA1 Gene Expression in Saccharomyces cerevisiae  

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Expression of genes encoding starch-degrading enzymes is regulated by glucose repression in the yeast Saccharomyces cerevisiae. We have identified a transcriptional repressor, Nrg1, in a genetic screen designed to reveal negative factors involved in the expression of STA1, which encodes a glucoamylase. The NRG1 gene encodes a 25-kDa C2H2 zinc finger protein which specifically binds to two regions in the upstream activation sequence of the STA1 gene, as judged by gel retardation and DNase I fo...

Park, Seok Hee; Koh, Sang Seok; Chun, Jae Hwan; Hwang, Hye Jin; Kang, Hyen Sam

1999-01-01

254

Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains  

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Full Text Available 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 selection 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.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 produção 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.

Míriam Cristina Sakuragui Matuo

2010-09-01

255

Optimization of protein extraction from the yeast Saccharomyces cerevisiae/
Otimização da extração de proteínas da levedura Saccharomyces cerevisiae
 

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This work aimed to determine the optimum temperature, pH and sodium chloride sodium concentration for protein extraction of yeast cells during autolysis process. The cellular extract was obtained using commercial compressed baker’s yeast Saccharomyces cerevisiae and for statistical analysis and definition of the variation levels of temperature (32,0 to 52,0°C), pH (1,32 to 7,00) and NaCl (2,0 to 75%) the Response Surface Analysis Methodology was used. The result obtained showed that the be...

Go?mez, Raul Jorge Hernan C.; Antonio Martins Oliveira

2005-01-01

256

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

Directory of Open Access Journals (Sweden)

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.

Raul Jorge Hernan Castro-Gómez

2008-08-01

257

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

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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.

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

1990-01-01

258

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

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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...

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

2007-01-01

259

Ethanolic fermentation of xylose with Saccharomyces cerevisiae harboring the Thermus thermophilus xylA gene, which expresses an active xylose (glucose) isomerase.  

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The Thermus thermophilus xylA gene encoding xylose (glucose) isomerase was cloned and expressed in Saccharomyces cerevisiae under the control of the yeast PGK1 promoter. The recombinant xylose isomerase showed the highest activity at 85 degrees C with a specific activity of 1.0 U mg-1. A new functional metabolic pathway in S. cerevisiae with ethanol formation during oxygen-limited xylose fermentation was demonstrated. Xylitol and acetic acid were also formed during the fermentation.

Walfridsson, M.; Bao, X.; Anderlund, M.; Lilius, G.; Bu?low, L.; Hahn-ha?gerdal, B.

1996-01-01

260

On the fermentative behavior of auxotrophic strains of Saccharomyces cerevisiae  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english 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.

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

2014-09-15

 
 
 
 
261

Polycistronic expression of a ?-carotene biosynthetic pathway in Saccharomyces cerevisiae coupled to ?-ionone production.  

Science.gov (United States)

The flavour and fragrance compound ?-ionone, which naturally occurs in raspberry and many other fruits and flowers, is currently produced by synthetic chemistry. This study describes a synthetic biology approach for ?-ionone production from glucose by Saccharomyces cerevisiae that is partially based on polycistronic expression. Experiments with model proteins showed that the T2A sequence of the Thosea asigna virus mediated efficient production of individual proteins from a single transcript in S. cerevisiae. Subsequently, three ?-carotene biosynthesis genes from the carotenoid-producing ascomycete Xanthophyllomyces dendrorhous (crtI, crtE and crtYB) were expressed in S. cerevisiae from a single polycistronic construct. In this construct, the individual crt proteins were separated by T2A sequences. Production of the individual proteins from the polycistronic construct was confirmed by Western blot analysis and by measuring the production of ?-carotene. To enable ?-ionone production, a carotenoid-cleavage dioxygenase from raspberry (RiCCD1) was co-expressed in the ?-carotene producing strain. In glucose-grown cultures with a second phase of dodecane, ?-ionone and geranylacetone accumulated in the organic phase. Thus, by introducing a polycistronic construct encoding a fungal carotenoid pathway and an expression cassette encoding a plant dioxygenase, a novel microbial production system has been established for a fruit flavour compound. PMID:24486029

Beekwilder, Jules; van Rossum, Harmen M; Koopman, Frank; Sonntag, Frank; Buchhaupt, Markus; Schrader, Jens; Hall, Robert D; Bosch, Dirk; Pronk, Jack T; van Maris, Antonius J A; Daran, Jean-Marc

2014-12-20

262

Saccharomyces cerevisiae Is Permissive for Replication of Bovine Papillomavirus Type 1  

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We recently demonstrated that Saccharomyces cerevisiae protoplasts can take up bovine papillomavirus type 1 (BPV1) virions and that viral episomal DNA is replicated after uptake. Here we demonstrate that BPV virus-like particles are assembled in infected S. cerevisiae cultures from newly synthesized capsid proteins and also package newly synthesized DNA, including full-length and truncated viral DNA and S. cerevisiae-derived DNA. Virus particles prepared in S. cerevisiae are able to convey pa...

Zhao, Kong-nan; Frazer, Ian H.

2002-01-01

263

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)

264

Role of social wasps in Saccharomyces cerevisiae ecology and evolution.  

Science.gov (United States)

Saccharomyces cerevisiae is one of the most important model organisms and has been a valuable asset to human civilization. However, despite its extensive use in the last 9,000 y, the existence of a seasonal cycle outside human-made environments has not yet been described. We demonstrate the role of social wasps as vector and natural reservoir of S. cerevisiae during all seasons. We provide experimental evidence that queens of social wasps overwintering as adults (Vespa crabro and Polistes spp.) can harbor yeast cells from autumn to spring and transmit them to their progeny. This result is mirrored by field surveys of the genetic variability of natural strains of yeast. Microsatellites and sequences of a selected set of loci able to recapitulate the yeast strain's evolutionary history were used to compare 17 environmental wasp isolates with a collection of strains from grapes from the same region and more than 230 strains representing worldwide yeast variation. The wasp isolates fall into subclusters representing the overall ecological and industrial yeast diversity of their geographic origin. Our findings indicate that wasps are a key environmental niche for the evolution of natural S. cerevisiae populations, the dispersion of yeast cells in the environment, and the maintenance of their diversity. The close relatedness of several wasp isolates with grape and wine isolates reflects the crucial role of human activities on yeast population structure, through clonal expansion and selection of specific strains during the biotransformation of fermented foods, followed by dispersal mediated by insects and other animals. PMID:22847440

Stefanini, Irene; Dapporto, Leonardo; Legras, Jean-Luc; Calabretta, Antonio; Di Paola, Monica; De Filippo, Carlotta; Viola, Roberto; Capretti, Paolo; Polsinelli, Mario; Turillazzi, Stefano; Cavalieri, Duccio

2012-08-14

265

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

Directory of Open Access Journals (Sweden)

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.

Sandrasegarampillai Balakumar

2012-03-01

266

Biogeographical characterisation of Saccharomyces cerevisiae wine yeast by molecular methods  

Directory of Open Access Journals (Sweden)

Full Text Available Biogeography is the descriptive and explanatory study of spatial patterns and processes involved in the distribution of biodiversity. Without biogeography, it would be difficult to study the diversity of microorganisms because there would be no way to visualise patterns in variation. Saccharomyces cerevisiae, “the wine yeast”, is the most important species involved in alcoholic fermentation, and in vineyard ecosystems, it follows the principle of “everything is everywhere”. Agricultural practices such as farming (organic versus conventional and floor management systems have selected different populations within this species that are phylogenetically distinct. In fact, recent ecological and geographic studies highlighted that unique strains are associated with particular grape varieties in specific geographical locations. These studies also highlighted that significant diversity and regional character, or ‘terroir’, have been introduced into the winemaking process via this association. This diversity of wild strains preserves typicity, the high quality and the unique flavour of wines. Recently, different molecular methods were developed to study population dynamics of S. cerevisiae strains in both vineyards and wineries. In this review, we will provide an update on the current molecular methods used to reveal the geographical distribution of S. cerevisiae wine yeast.

RosannaTofalo

2013-06-01

267

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

Sandrasegarampillai, Balakumar; Vasanthy, Arasaratnam.

2012-03-01

268

Molecular biology of iron acquisition in Saccharomyces cerevisiae.  

Science.gov (United States)

In recent years, significant advances have been made in our understanding of the mechanism and regulation of elemental iron transport in the eukaryote Saccharomyces cerevisiae. This organism employs two distinct iron-transport systems, depending on the bioavailability of the metal. In iron-replete environments, a low-affinity transport system (K(m) = 30 microM) is used to acquire iron. This system may also be used to acquire other metals including cobalt and cadmium. When environmental iron is limiting, a high-affinity (K(m) = 0.15 microM) iron-transport system is induced. Genetic studies in S. cerevisiae have identified multiple genes involved in both iron-transport systems. Cell-surface reductases, FRE1 and FRE2, provide ferrous iron for both systems. A non-ATP-dependent transmembrane transporter (FET4) has been identified as the main component of low-affinity transport. One gene identified to date as part of the high-affinity transport system is FET3, which shows high sequence and functional homology to multicopper oxidases. Accessory genes required for the functioning of this transport system include a plasma-membrane copper transporter (CTR1), an intracellular copper transporter (CCC2), and a putative transcription factor (AFT1). The mechanism by which these genes act in concert to ensure iron accumulation in S. cerevisiae presents an intriguing picture, drawing parallels with observations made in the human system almost 40 years ago. PMID:8861201

Askwith, C C; de Silva, D; Kaplan, J

1996-04-01

269

The postmitotic Saccharomyces cerevisiae after spaceflight showed higher viability  

Science.gov (United States)

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.

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

2011-06-01

270

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

271

Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

Vemuri, Goutham; Eiteman, M.A

2007-01-01

272

Ciclohexadespipeptide beauvericin degradation by different strains of Saccharomyces cerevisiae.  

Science.gov (United States)

The interaction between the mycotoxin beauvericin (BEA) and 9 yeast strains of Saccharomyces cerevisiae named LO9, YE-2, YE5, YE-6, YE-4, A34, A17, A42 and A08 was studied. The biological degradations were carried out under aerobic conditions in the liquid medium of Potato Dextrose Broth (PDB) at 25°C for 48 h and in a food/feed system composed of corn flour at 37°C for 3 days, respectively. BEA present in fermented medium and corn flour was determined using liquid chromatography coupled to the mass spectrometry detector in tandem (LC-MS/MS) and the BEA degradation products produced during the fermentations were determined using the technique of the liquid chromatography coupled to a linear ion trap (LIT). Results showed that the S. cerevisiae strains reduced meanly the concentration of the BEA present in PDB by 86.2% and in a food system by 71.1%. All the S. cerevisiae strains used in this study showed a significant BEA reduction during the fermentation process employed. PMID:23791659

Meca, G; Zhou, T; Li, X Z; Ritieni, A; Mañes, J

2013-09-01

273

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

DEFF Research Database (Denmark)

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.

Siewers, Verena; Chen, Xiao

2009-01-01

274

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

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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...

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

2011-01-01

275

Anaplerotic Role for Cytosolic Malic Enzyme in Engineered Saccharomyces cerevisiae Strains?  

Science.gov (United States)

Malic enzyme catalyzes the reversible oxidative decarboxylation of malate to pyruvate and CO2. The Saccharomyces cerevisiae MAE1 gene encodes a mitochondrial malic enzyme whose proposed physiological roles are related to the oxidative, malate-decarboxylating reaction. Hitherto, the inability of pyruvate carboxylase-negative (Pyc?) S. cerevisiae strains to grow on glucose suggested that Mae1p cannot act as a pyruvate-carboxylating, anaplerotic enzyme. In this study, relocation of malic enzyme to the cytosol and creation of thermodynamically favorable conditions for pyruvate carboxylation by metabolic engineering, process design, and adaptive evolution, enabled malic enzyme to act as the sole anaplerotic enzyme in S. cerevisiae. The Escherichia coli NADH-dependent sfcA malic enzyme was expressed in a Pyc? S. cerevisiae background. When PDC2, a transcriptional regulator of pyruvate decarboxylase genes, was deleted to increase intracellular pyruvate levels and cells were grown under a CO2 atmosphere to favor carboxylation, adaptive evolution yielded a strain that grew on glucose (specific growth rate, 0.06 ± 0.01 h?1). Growth of the evolved strain was enabled by a single point mutation (Asp336Gly) that switched the cofactor preference of E. coli malic enzyme from NADH to NADPH. Consistently, cytosolic relocalization of the native Mae1p, which can use both NADH and NADPH, in a pyc1,2? pdc2? strain grown under a CO2 atmosphere, also enabled slow-growth on glucose. Although growth rates of these strains are still low, the higher ATP efficiency of carboxylation via malic enzyme, compared to the pyruvate carboxylase pathway, may contribute to metabolic engineering of S. cerevisiae for anaerobic, high-yield C4-dicarboxylic acid production. PMID:21131518

Zelle, Rintze M.; Harrison, Jacob C.; Pronk, Jack T.; van Maris, Antonius J. A.

2011-01-01

276

Anaplerotic role for cytosolic malic enzyme in engineered Saccharomyces cerevisiae strains.  

Science.gov (United States)

Malic enzyme catalyzes the reversible oxidative decarboxylation of malate to pyruvate and CO(2). The Saccharomyces cerevisiae MAE1 gene encodes a mitochondrial malic enzyme whose proposed physiological roles are related to the oxidative, malate-decarboxylating reaction. Hitherto, the inability of pyruvate carboxylase-negative (Pyc(-)) S. cerevisiae strains to grow on glucose suggested that Mae1p cannot act as a pyruvate-carboxylating, anaplerotic enzyme. In this study, relocation of malic enzyme to the cytosol and creation of thermodynamically favorable conditions for pyruvate carboxylation by metabolic engineering, process design, and adaptive evolution, enabled malic enzyme to act as the sole anaplerotic enzyme in S. cerevisiae. The Escherichia coli NADH-dependent sfcA malic enzyme was expressed in a Pyc(-) S. cerevisiae background. When PDC2, a transcriptional regulator of pyruvate decarboxylase genes, was deleted to increase intracellular pyruvate levels and cells were grown under a CO(2) atmosphere to favor carboxylation, adaptive evolution yielded a strain that grew on glucose (specific growth rate, 0.06 ± 0.01 h(-1)). Growth of the evolved strain was enabled by a single point mutation (Asp336Gly) that switched the cofactor preference of E. coli malic enzyme from NADH to NADPH. Consistently, cytosolic relocalization of the native Mae1p, which can use both NADH and NADPH, in a pyc1,2? pdc2? strain grown under a CO(2) atmosphere, also enabled slow-growth on glucose. Although growth rates of these strains are still low, the higher ATP efficiency of carboxylation via malic enzyme, compared to the pyruvate carboxylase pathway, may contribute to metabolic engineering of S. cerevisiae for anaerobic, high-yield C(4)-dicarboxylic acid production. PMID:21131518

Zelle, Rintze M; Harrison, Jacob C; Pronk, Jack T; van Maris, Antonius J A

2011-02-01

277

Expression of an endoglucanase from Tribolium castaneum (TcEG1) in Saccharomyces cerevisiae.  

Science.gov (United States)

Insects are a largely unexploited resource in prospecting for novel cellulolytic enzymes to improve the production of ethanol fuel from lignocellulosic biomass. The cost of lignocellulosic ethanol production is expected to decrease by the combination of cellulose degradation (saccharification) and fermentation of the resulting glucose to ethanol in a single process, catalyzed by the yeast Saccharomyces cerevisiae transformed to express efficient cellulases. While S. cerevisiae is an established heterologous expression system, there are no available data on the functional expression of insect cellulolytic enzymes for this species. To address this knowledge gap, S. cerevisiae was transformed to express the full-length cDNA encoding an endoglucanase from the red flour beetle, Tribolium castaneum (TcEG1), and evaluated the activity of the transgenic product (rTcEG1). Expression of the TcEG1 cDNA in S. cerevisiae was under control of the strong glyceraldehyde-3 phosphate dehydrogenase promoter. Cultured transformed yeast secreted rTcEG1 protein as a functional ?-1,4-endoglucanase, which allowed transformants to survive on selective media containing cellulose as the only available carbon source. Evaluation of substrate specificity for secreted rTcEG1 demonstrated endoglucanase activity, although some activity was also detected against complex cellulose substrates. Potentially relevant to uses in biofuel production rTcEG1 activity increased with pH conditions, with the highest activity detected at pH 12. Our results demonstrate the potential for functional production of an insect cellulase in S. cerevisiae and confirm the stability of rTcEG1 activity in strong alkaline environments. PMID:24318365

Shirley, Derek; Oppert, Cris; Reynolds, Todd B; Miracle, Bethany; Oppert, Brenda; Klingeman, William E; Jurat-Fuentes, Juan Luis

2014-10-01

278

Impact of systems biology on metabolic engineering of Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

Nielsen, Jens; Jewett, Michael Christopher

2008-01-01

279

Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress  

Science.gov (United States)

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 mechanisms 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 ?g/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. PMID:24516431

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

2013-01-01

280

Partial purification of Holliday junction resolvase activity from Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Toward the goal of understanding genetic recombination on a molecular level, we are focusing on the essential final step, resolution of the Holliday junction intermediate. This report describes progress in the purification and characterization of this activity from the yeast Saccharomyces cerevisiae. Resolvase activity is assayed by conversion of cruciform-containing supercoiled pBR322 dimer DNA or cruciform-containing supercoiled ColE1 DNA to linear forms by cleavage at the base of the cruciform. Resolvase activity, which can be detected in cell-free extracts prepared from haploid and diploid mitotic cells, is dependent on the presence of magnesium, is independent of ATP, and the reaction is inhabited by concentrations of sodium or potassium chloride of 100 mM or greater. Linear DNA is not a substrate for this activity. 6 refs., 8 figs

 
 
 
 
281

Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure  

Science.gov (United States)

Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.

2014-05-01

282

Isolation of thermotolerant, osmotolerant, flocculating Saccharomyces cerevisiae for ethanol production  

Energy Technology Data Exchange (ETDEWEB)

Four thermotolerant, osmotolerant, flocculating alcohol producing cultures of Saccharomyces cerevisiae were isolated from soil samples collected from a thermal power plant in India. All the isolates grew at 44{sup o}C but VS{sub 1} and VS{sub 3} were better than the other two. Maximum ethanol yields obtained from 150 g/l glucose were 75 and 60 g/l using culture VS{sub 3} at 30{sup o}C and 40{sup o}C, respectively. Growth and ethanol production were decreasing at 44{sup o}C so higher temperatures were not tested, but the isolates could tolerate temperatures above 44{sup o}C. All cultures belonged to class IV flocculating yeasts and were able to tolerate up to 350 g/l glucose. These cultures have economical importance for use in alcohol production during hot seasons in countries such as India. (author)

Kiran Sree, N.; Sridhar, M.; Suresh, K.; Venkateswar Rao, L. [Osmania Univ., Hyderabad (India). Dept. of Microbiology; Banat, I.M. [University of Ulster, Coleraine, Northern Ireland (United Kingdom). Biotechnology Group

2000-03-01

283

Metabolic engineering of Saccharomyces cerevisiae for production of butanol isomers.  

Science.gov (United States)

Saccharomyces cerevisiae has decisive advantages in industrial processes due to its tolerance to alcohols and fermentation conditions. Butanol isomers are considered as suitable fuel substitutes and valuable biomass-derived chemical building blocks. Whereas high production was achieved with bacterial systems, metabolic engineering of yeast for butanol production is in the beginning. For isobutanol synthesis, combination of valine biosynthesis and degradation, and complete pathway re-localisation into cytosol or mitochondria gave promising results. However, competing pathways, co-factor imbalances and FeS cluster assembly are still major issues. 1-Butanol production via the Clostridium pathway seems to be limited by cytosolic acetyl-CoA, its central precursor. Endogenous 1-butanol pathways have been discovered via threonine or glycine catabolism. 2-Butanol production was established but was limited by B12-dependence. PMID:25286420

Generoso, Wesley Cardoso; Schadeweg, Virginia; Oreb, Mislav; Boles, Eckhard

2014-10-01

284

Fluorescence staining of mitochondria for morphology analysis in Saccharomyces cerevisiae.  

Science.gov (United States)

Mitochondria are highly dynamic organelles in all eukaryotic cells. Most of our insights regarding the mechanisms that determine the morphogenesis and motility of mitochondria have been identified and analyzed first in the model organism Saccharomyces cerevisiae. To this end high-resolution microscopic methods were applied that rely on fluorescence labeling of the organelle. A comprehensive overview of fluorescence staining approaches that were successfully applied to study the behavior of mitochondria in vivo but also in fixed cells is provided. Slightly modified versions of the methods described here can also be used to analyze other compartments of the yeast cell. Microscopic setups and imaging methods will only be shortly discussed since these are highly dependent on each laboratory's basic infrastructure. PMID:24841303

Dimmer, Kai Stefan

2014-01-01

285

Mutations in Ran system affected telomere silencing in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

The Ran GTPase system regulates the direction and timing of several cellular events, such as nuclear-cytosolic transport, centrosome formation, and nuclear envelope assembly in telophase. To gain insight into the Ran system's involvement in chromatin formation, we investigated gene silencing at the telomere in several mutants of the budding yeast Saccharomyces cerevisiae, which had defects in genes involved in the Ran system. A mutation of the RanGAP gene, rna1-1, caused reduced silencing at the telomere, and partial disruption of the nuclear Ran binding factor, yrb2-?2, increased this silencing. The reduced telomere silencing in rna1-1 cells was suppressed by a high dosage of the SIR3 gene or the SIT4 gene. Furthermore, hyperphosphorylated Sir3 protein accumulated in the rna1-1 mutant. These results suggest that RanGAP is required for the heterochromatin structure at the telomere in budding yeast

286

Saccharomyces cerevisiae: a potential biosorbent for biosorption of uranium.  

Directory of Open Access Journals (Sweden)

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.

PROF. RAJESH DHANKHAR

2011-06-01

287

Expression of cytochrome P-450d by Saccharomyces cerevisiae.  

Science.gov (United States)

Rat liver microsomal cytochrome P-450d was abundantly expressed in the yeast Saccharomyces cerevisiae by using a yeast-Escherichia coli shuttle vector consisting of rat liver P-450d cDNA and yeast acid phosphatase promoter. The expressed cytochrome P-450d was immunologically crossed with rat liver P-450d. The hydroxylase activity of estra-1,3,5(10)-triene-3, 17 beta-diol was 11 nmol/min per nmol P-450d, which is comparable to that reported previously for rat liver P-450d. The expressed P-450d content was nearlyt 1% of total yeast protein as estimated from immunoblotting, hydroxylase activity and optical absorpton of the reduced CO form. PMID:3533629

Shimizu, T; Sogawa, K; Fujii-Kuriyama, Y; Takahashi, M; Ogoma, Y; Hatano, M

1986-10-27

288

Higher-order structure of Saccharomyces cerevisiae chromatin  

International Nuclear Information System (INIS)

We have developed a method for partially purifying chromatin from Saccharomyces cerevisiae (baker's yeast) to a level suitable for studies of its higher-order folding. This has required the use of yeast strains that are free of the ubiquitous yeast killer virus. Results from dynamic light scattering, electron microscopy, and x-ray diffraction show that the yeast chromatin undergoes a cation-dependent folding into 30-nm filaments that resemble those characteristic of higher-cell chromatin; moreover, the packing of nucleosomes within the yeast 30-nm filaments is similar to that of higher cells. These results imply that yeast has a protein or protein domain that serves the role of the histone H 1 found in higher cells; physical and genetic studies of the yeast activity could help elucidate the structure and function of H 1. Images of the yeast 30-nm filaments can be used to test crossed-linker models for 30-nm filament structure

289

Structural properties of Saccharomyces cerevisiae protein complex network  

CERN Document Server

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...

Ramezanpour, A; Karimipour, V

2003-01-01

290

Adaptive answer to low ionizing radiation doses in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

The aim of this work is to verify the existence of the adaptive response phenomenon induced by low doses of ionizing radiation in living cells. It is known that low doses of ionizing radiation, called conditioning doses, may induce resistance in exposed organisms to higher doses, called challenging doses, which are applied after a period of time. The involved mechanisms in this phenomenon, called Adaptive Response, are diverse and complex. Among them, the most important are the activation of DNA-repair enzymes and nuclear recombination process. As the 'target' sample, it was utilized a 'wild type' strain of Saccharomyces cerevisiae in aqueous suspension. Adaptive Response was verified in a wide range of challenging doses. Conditioning doses, inductors of radio-resistance, were (0.44±0.03) Gy and the waiting time between them and challenging doses was 2 hours at room temperature.(author)

291

Pyrimidine-specific cleavage by an endoribonuclease of Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

An endoribonuclease with pyrimidine cleavage site specificity was isolated from Saccharomyces cerevisiae. The enzyme had a pH optimum of 6 to 7 and did not require a divalent cation. It was inhibited by 5 x 10-5 M hetidium bromide, although it appeared to be single strand specific. The enzyme gave a limited cleavage of yeast mRNA and rRNA, yielding products that were terminated with pyrimidine nucleoside 2',3'-cyclic phosphate. The bonds between pyrimidine and A residues constituted more than 90% of the scission sites when the average product size was 50 nucloetides. Homopolyribonucleotides were cleaved poorly. Poly(A,U) was cleaved rapidly, and analysis of the products of poly(A,U) hydrolysis showed a very stringent cleavage of U-A bonds

292

Probing glycolytic and membrane potential oscillations in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

We have investigated glycolytic oscillations under semi-anaerobic conditions in Saccharomyces cerevisiae by means of NADH fluorescence, measurements of intracellular glucose concentration, and mitochondrial membrane potential. The glucose concentration was measured using an optical nanosensor, while mitochondrial membrane potential was measured using the fluorescent dye DiOC 2(3). The results show that, as opposed to NADH and other intermediates in glycolysis, intracellular glucose is not oscillating. Furthermore, oscillations in NADH and membrane potential are inhibited by the ATP/ADP antiporter inhibitor atractyloside and high concentrations of the ATPase inhibitor N, N'-dicyclohexylcarbodiimide, suggesting that there is a strong coupling between oscillations in mitochondrial membrane potential and oscillations in NADH mediated by the ATP/ADP antiporter and possibly also other respiratory components.

Poulsen, Allan K; Andersen, Ann Zahle

2008-01-01

293

Replication of avocado sunblotch viroid in the yeast Saccharomyces cerevisiae.  

Science.gov (United States)

Viroids are the smallest known pathogenic agents. They are noncoding, single-stranded, closed-circular, "naked" RNAs, which replicate through RNA-RNA transcription. Viroids of the Avsunviroidae family possess a hammerhead ribozyme in their sequence, allowing self-cleavage during their replication. To date, viroids have only been detected in plant cells. Here, we investigate the replication of Avocado sunblotch viroid (ASBVd) of the Avsunviroidae family in a nonconventional host, the yeast Saccharomyces cerevisiae. We demonstrate that ASBVd RNA strands of both polarities are able to self-cleave and to replicate in a unicellular eukaryote cell. We show that the viroid monomeric RNA is destabilized by the nuclear 3' and the cytoplasmic 5' RNA degradation pathways. For the first time, our results provide evidence that viroids can replicate in other organisms than plants and that yeast contains all of the essential cellular elements for the replication of ASBVd. PMID:21270165

Delan-Forino, Clémentine; Maurel, Marie-Christine; Torchet, Claire

2011-04-01

294

Replication of Avocado Sunblotch Viroid in the Yeast Saccharomyces cerevisiae?  

Science.gov (United States)

Viroids are the smallest known pathogenic agents. They are noncoding, single-stranded, closed-circular, “naked” RNAs, which replicate through RNA-RNA transcription. Viroids of the Avsunviroidae family possess a hammerhead ribozyme in their sequence, allowing self-cleavage during their replication. To date, viroids have only been detected in plant cells. Here, we investigate the replication of Avocado sunblotch viroid (ASBVd) of the Avsunviroidae family in a nonconventional host, the yeast Saccharomyces cerevisiae. We demonstrate that ASBVd RNA strands of both polarities are able to self-cleave and to replicate in a unicellular eukaryote cell. We show that the viroid monomeric RNA is destabilized by the nuclear 3? and the cytoplasmic 5? RNA degradation pathways. For the first time, our results provide evidence that viroids can replicate in other organisms than plants and that yeast contains all of the essential cellular elements for the replication of ASBVd. PMID:21270165

Delan-Forino, Clémentine; Maurel, Marie-Christine; Torchet, Claire

2011-01-01

295

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2010-01-01

296

Water treatment process and system for metals removal using Saccharomyces cerevisiae  

Science.gov (United States)

A process and a system for removal of metals from ground water or from soil by bioreducing or bioaccumulating the metals using metal tolerant microorganisms Saccharomyces cerevisiae. Saccharomyces cerevisiae is tolerant to the metals, able to bioreduce the metals to the less toxic state and to accumulate them. The process and the system is useful for removal or substantial reduction of levels of chromium, molybdenum, cobalt, zinc, nickel, calcium, strontium, mercury and copper in water.

Krauter, Paula A. W. (Livermore, CA); Krauter, Gordon W. (Livermore, CA)

2002-01-01

297

PHENOTYPES INVESTIGATION IN THE YEAST SACCHAROMYCES CEREVISIAE ISOLATED FROM DIFFERENT GRAPE CULTIVARS FOLLOWIG FERMENTATION  

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Micobiological investigation was carried out on Saccharomyces cerevisiae yeast cultures, which were isolated from different varieties of vintage grape harvested from the ?Koblevo? winery, Nikolaev region of Ukraine. It was determined that wild yeast cultures tend to be of one of three different phenotypes. For comparison and reference, investigation of test cultures was performed with previously known phenotypes and yeast cultures Saccharomyces cerevisiae used in wine industry. It was n...

Bayraktar V. N.

2012-01-01

298

Repair of UV-damaged incoming plasmid DNA in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

A whole-cell transformation assay was used for the repair of UV-damaged plasma DNA in highly-transformable haploid strains of Saccharomyces cerevisiae having different repair capabilities. The experiments described demonstrate that three epistasis groups (Friedberg 1988) are involved in the repair of UV-incoming DNA and that the repair processes act less efficiently on incoming DNA than they do on chromosomal DNA. The implications of these findings for UV repair in Saccharomyces cerevisiae are discussed. (author)

299

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

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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...

Pejin Dušanka J.; Vasi? Vesna M.

2005-01-01

300

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 div...

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

2013-01-01

 
 
 
 
301

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2008-11-25

302

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

Directory of Open Access Journals (Sweden)

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.

Myers Samuel

2008-12-01

303

Completion of Replication Map of Saccharomyces cerevisiae Chromosome III  

Science.gov (United States)

In Saccharomyces cerevisiae chromosomal DNA replication initiates at intervals of ?40 kb and depends upon the activity of autonomously replicating sequence (ARS) elements. The identification of ARS elements and analysis of their function as chromosomal replication origins requires the use of functional assays because they are not sufficiently similar to identify by DNA sequence analysis. To complete the systematic identification of ARS elements on S. cerevisiae chromosome III, overlapping clones covering 140 kb of the right arm were tested for their ability to promote extrachromosomal maintenance of plasmids. Examination of chromosomal replication intermediates of each of the seven ARS elements identified revealed that their efficiencies of use as chromosomal replication origins varied widely, with four ARS elements active in ?10% of cells in the population and two ARS elements active in ?90% of the population. Together with our previous analysis of a 200-kb region of chromosome III, these data provide the first complete analysis of ARS elements and DNA replication origins on an entire eukaryotic chromosome. PMID:11694569

Poloumienko, Arkadi; Dershowitz, Ann; De, Jitakshi; Newlon, Carol S.

2001-01-01

304

[Regulatory role of monoamine neurotransmitters in Saccharomyces cerevisiae cells].  

Science.gov (United States)

Proliferation of Saccharomyces cerevisiae EPF cells on solid maltose-peptone-yeast extract (MPY) medium was stimulated by the addition of monoamine neurotransmitters. Dopamine turned out to be the most efficient among them: it caused approximately 8-fold growth stimulation at 1 microM concentration. The dopamine effect was partly mimicked by apomorphine, a dopamine receptor agonist. Serotonin and histamine produced less significant (1.5-2-fold) effects, and norepinephrine virtually failed to stimulate yeast culture growth. These data point to a specific, apparently receptor-dependent mode of action of the tested neurotransmitters on S. cerevisiae cells. Using high efficiency liquid chromatography, serotonin, catecholamines (dopamine and norepinephrine), catecholamines precursor dioxyphenylamine, and oxidized amine products (homovanilic acid, dihydrophenylacetic acid, and 5-hydroxyindolacetic acid) were established to be accumulated in yeast cells up to (sub)micromolar concentrations without their release into the culture fluid supernatant (CSF). The results obtained suggest that the tested amine neurotransmitters and related compounds do not serve as autoregulators in the yeast population. Nevertheless, they may be involved in the regulation of yeast population development by other ecosystem components. PMID:21261078

Malikina, K D; Shishov, V A; Chuvelev, D I; Kudrin, V S; Oleskin, A V

2010-01-01

305

Quantifying separation and similarity in a Saccharomyces cerevisiae metapopulation.  

Science.gov (United States)

Eukaryotic microbes are key ecosystem drivers; however, we have little theory and few data elucidating the processes influencing their observed population patterns. Here we provide an in-depth quantitative analysis of population separation and similarity in the yeast Saccharomyces cerevisiae with the aim of providing a more detailed account of the population processes occurring in microbes. Over 10?000 individual isolates were collected from native plants, vineyards and spontaneous ferments of fruit from six major regions spanning 1000?km across New Zealand. From these, hundreds of S. cerevisiae genotypes were obtained, and using a suite of analytical methods we provide comprehensive quantitative estimates for both population structure and rates of gene flow or migration. No genetic differentiation was detected within geographic regions, even between populations inhabiting native forests and vineyards. We do, however, reveal a picture of national population structure at scales above ?100?km with distinctive populations in the more remote Nelson and Central Otago regions primarily contributing to this. In addition, differential degrees of connectivity between regional populations are observed and correlate with the movement of fruit by the New Zealand wine industry. This suggests some anthropogenic influence on these observed population patterns. PMID:25062126

Knight, Sarah; Goddard, Matthew R

2015-02-01

306

Sweet wine production by two osmotolerant Saccharomyces cerevisiae strains.  

Science.gov (United States)

The use of Saccharomyces cerevisiae to produce sweet wine is difficult because yeast is affected by a hyperosmotic stress due to the high sugar concentrations in the fermenting must. One possible alternative could be the coimmobilization of the osmotolerant yeast strains S. cerevisiae X4 and X5 on Penicillium chrysogenum strain H3 (GRAS) for the partial fermentation of raisin musts. This immobilized has been, namely, as yeast biocapsules. Traditional sweet wine (that is, without fermentation of the must) and must partially fermented by free yeast cells were also used for comparison. Partially fermented sweet wines showed higher concentration of the volatile compounds than traditionally produced wines. The wines obtained by immobilized yeast cells reached minor concentrations of major alcohols than wines by free cells. The consumption of specific nitrogen compounds was dependent on yeast strain and the cellular immobilization. A principal component analysis shows that the compounds related to the response to osmotic stress (glycerol, acetaldehyde, acetoin, and butanediol) clearly differentiate the wines obtained with free yeasts but not the wines obtained with immobilized yeasts. PMID:23601087

García-Martínez, Teresa; de Lerma, Nieves López; Moreno, Juan; Peinado, Rafael A; Millán, M Carmen; Mauricio, Juan C

2013-06-01

307

High level secretion of cellobiohydrolases by Saccharomyces cerevisiae  

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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.

Ahlgren Simon

2011-09-01

308

Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

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.

Hou, Jin; Österlund, Tobias

2013-01-01

309

Engineered production of fungal anticancer cyclooligomer depsipeptides in Saccharomyces cerevisiae.  

Science.gov (United States)

Two fungal cyclooligomer depsipeptide synthetases(CODSs), BbBEAS (352 kDa) and BbBSLS (348 kDa) from Beauveria bassiana ATCC7159, were reconstituted in Saccharomyces cerevisiae BJ5464-NpgA, leading to the production of the corresponding anticancer natural products, beauvericins and bassianolide, respectively. The titers of beauvericins (33.8 ± 1.4 mg/l) and bassianolide (21.7± 0.1 mg/l) in the engineered S. cerevisiae BJ5464-NpgA strains were comparable to those in the native producer B. bassiana. Feeding D-hydroxyisovaleric acid (D-Hiv) and the corresponding L-amino acid precursors improved the production of beauvericins and bassianolide. However, the high price of D-Hiv limits its application in large-scale production of these cyclooligomer depsipeptides. Alternatively, we engineered another enzyme, ketoisovalerate reductase (KIVR) from B. bassiana, into S. cerevisiae BJ5464-NpgA for enhanced in situ synthesis of this expensive substrate. Co-expression of BbBEAS and KIVR in the yeast led to significant improvement of the production of beauvericins.The total titer of beauvericin and its congeners (beauvericins A-C) was increased to 61.7 ± 3.0 mg/l and reached 2.6-fold of that in the native producer B. bassiana ATCC7159. Supplement of L-Val at 10 mM improved the supply of ketoisovalerate, the substrate of KIVR, which consequently further increased the total titer of beauvericins to 105.8 ± 2.1 mg/l. Using this yeast system,we functionally characterized an unknown CODS from Fusarium venenatum NRRL 26139 as a beauvericin synthetase, which was named as FvBEAS. Our work thus provides a useful approach for functional reconstitution and engineering of fungal CODSs for efficient production of this family of anticancer molecules. PMID:23608474

Yu, Dayu; Xu, Fuchao; Zi, Jiachen; Wang, Siyuan; Gage, David; Zeng, Jia; Zhan, Jixun

2013-07-01

310

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

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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.

Joelma Morais Ferreira

2007-10-01

311

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] 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.

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

1188-11-01

312

Genome-wide transcriptional response of a Saccharomyces cerevisiae strain with an altered redox metabolism  

DEFF Research Database (Denmark)

The genome-wide transcriptional response of a Saccharomyces cerevisiae strain deleted in GDH1 that encodes a NADP(+)-dependent glutamate dehydrogenase was compared to a wild-type strain under anaerobic steady-state conditions. The GDH1-deleted strain has a significantly reduced NADPH requirement, and therefore, an altered redox metabolism. Identification of genes with significantly changed expression using a t-test and a Bonferroni correction yielded only 16 transcripts when accepting two false-positives, and 7 of these were Open Reading Frames (ORFs) with unknown function. Among the 16 transcripts the only one with a direct link to redox metabolism was GND1, encoding phosphogluconate dehydrogenase. To extract additional information we analyzed the transcription data for a gene subset consisting of all known genes encoding metabolic enzymes that use NAD(+) or NADP(+). The subset was analyzed for genes with significantly changed expression again with a t-test and correction for multiple testing. This approach was found to enrich the analysis since GND1, ZWF1 and ALD6, encoding the most important enzymes for regeneration of NADPH under anaerobic conditions, were down-regulated together with eight other genes encoding NADP(H)-dependent enzymes. This indicates a possible common redox-dependent regulation of these genes. Furthermore, we showed that it might be necessary to analyze the expression of a subset of genes to extract all available information from global transcription analysis.

Bro, Christoffer; Regenberg, Birgitte

2004-01-01

313

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

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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 u...

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

2013-01-01

314

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

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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.

Wang, Shi-an; Li, Fu-li

2013-01-01

315

ISOLATION OF A CYTOCHROME P-450 STRUCTURAL GENE FROM SACCHAROMYCES CEREVISIAE  

Science.gov (United States)

We have transformed a Saccharomyces cerevisiae host with an S. cerevisiae genomic library contained in the shuttle vector YEp24 and screened the resultant transformants for resistance to ketoconazole (Kc), an inhibitor of the cytochrome P-450 (P-450) enzyme lanosterol 14-demethyl...

316

Thermal stabilization of putative karyoskeletal protein-enriched fractions from Saccharomyces cerevisiae.  

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Elevated growth temperature (heat shock) promoted the structural stability of karyoskeletal protein-enriched fractions isolated from Saccharomyces cerevisiae. Similar stabilization could be induced by brief incubation of nuclei at 37 degrees C in vitro. These results are similar to those reported for higher eucaryotes and have practical implications for investigation of the karyoskeleton in S. cerevisiae.

Berrios, S.; Fisher, P. A.

1988-01-01

317

Killer toxin of Saccharomyces cerevisiae Y500-4L active against Fleischmann and Itaiquara commercial brands of yeast / Toxina "killer" de Saccharomyces cerevisiae Y500-4L ativa contra leveduras comerciais Fleischmann e Itaiquara  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A linhagem de Saccharomyces cerevisiae Y500-4L com alta capacidade fermentativa e atividade "killer", previamente selecionada de mosto de fermentação de usina de álcool, foi caracterizada quanto ao espectro de atividade e quanto à perda do caracter "killer". A linhagem "killer" de S. cerevisiae Y500 [...] -4L, mostrou alta atividade "killer" contra as leveduras comerciais Fleischmann e Itaiquara, e também contra as linhagens "killer" padrões K2 (S. diastaticus NCYC 713), K4 (Candida glabrata NCYC 388) e K11 (Torulopsis glabrata ATCC 15126) e mostrou ser sensível às toxinas produzidas pelas leveduras padrões "killer" K8 (Hansenula anomala NCYC 435), K9 (Hansenula mrakii NCYC 500), K10 (Kluyveromyces drosophilarum NCYC 575) e K11 (Torulopsis glabrata ATCC 15126). A linhagem de S. cerevisiae Y500-4L não apresentou plasmídio M-dsRNA e, provavelmente, o caracter genético responsável pelo fenótipo "killer" é codificado por genes cromossomais. Em ensaios para a perda do fenótipo, a linhagem S. cerevisiae Y500-4L apresentou maior resistência ao tratamento com cicloheximida e a temperatura elevada (40oC) do que a levedura S. cerevisiae padrão "killer" K1. Abstract in english 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 t [...] he 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.

Giselle A.M., Soares; Hélia H., Sato.

1999-07-01

318

Analysis of Key Factors Affecting Ethanol Production by Saccharomyces cerevisiae IFST-072011  

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Ethanol production by Saccharomyces cerevisiae is affected not only by fermentation conditions (temperature, pH and sugar concentration) but also by the intrinsic factors e.g., culture medium, dissolved O2, immobilization and other micronutrients. In order to investigate the influence of key factors on ethanol production by S. cerevisiae, a laboratory strain S. cerevisiae IFST-072011 was used in this study. Several fermentation runs were carried out varyi...

Monzur Morshed Ahmed; Md. Abdul Quayum; Md. Fakruddin; Naiyyum Choudhury

2012-01-01

319

Effects of ethanol and other alkanols on the general amino acid permease of saccharomyces cerevisiae  

Energy Technology Data Exchange (ETDEWEB)

Among the mechanisms that underlie the inhibition by alkanols of growth and fermentation in Saccharomyces cerevisiae, the noncompetitive exponential inhibition of nutrient transport across the plasma membrane may play a major role. So far this type of inhibition was shown to affect the transport systems of S. cerevisiae for glucose, maltose, and ammonium. The effects of ethanol, isopropanol, propanol, and butanol on the functioning of the general amino acid permease (GAP) of S. cerevisiae are reported.

Leao, C.; Van Uden, N.

1984-01-01

320

Physiological and molecular characterisation of Saccharomyces cerevisiae cachaça strains isolated from different geographic regions in Brazil  

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In this work, 74 Saccharomyces cerevisiae strains isolated from cachaça fermentation of six different geographic regions in Brazil were characterized by mitochondrial DNA restriction fragment length polymorphism (mtDNA-RFLP) and by their ability to grow on stress conditions occurring during the cachaça fermentation process. Cachaça S. cerevisiae strains showed high mtDNA-RFLP polymorphism with the occurrence of 32 different molecular patterns. The S. cerevisiae strains presenting prevalent...

Badotti, F.; Belloch, C.; Rosa, Ca; Barrio, E.; Querol, A.

2010-01-01

 
 
 
 
321

Development of Efficient Xylose Fermentation in Saccharomyces cerevisiae: Xylose Isomerase as a Key Component:  

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Metabolic engineering of Saccharomyces cerevisiae for ethanol production from d-xylose, an abundant sugar in plant biomass hydrolysates, has been pursued vigorously for the past 15 years. Whereas wild-type S. cerevisiae cannot ferment d-xylose, the ketoisomer d-xylulose can be metabolised slowly. Conversion of d-xylose into d-xylulose is therefore crucial in metabolic engineering of xylose fermentation by S. cerevisiae. Expression of heterologous xylose reductase and xylitol dehydrogenase doe...

Maris, A. J. A.; Winkler, A. A.; Kuyper, M.; Laat, W. T.; Dijken, J. P.; Pronk, J. T.

2007-01-01

322

Four genes responsible for a position effect on expression from HML and HMR in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Mating type interconversion in Saccharomyces cerevisiae occurs by transposition of copies of the a or ? mating type cassettes from inactive loci, HML and HMR, to an active locus, MAT. The lack of expression of the a and ? genes at the silent loci results from repression by trans-acting regulators encoded by SIR (Silent Information Regulator) genes. In this paper the authors present evidence for the existence of four SIR genes. Inactivation of any of these genes leads to expression of cassettes at both HML and HMR. Unusual complementation properties are observed for a number of sir mutations. Specifically, some recessive mutations in different genes fail to complement. The correspondence between SIR1, SIR2, SIR3, SIR4 and other genes with similar roles (MAR, CMT, STE8 and STE9) is presented

323

The Saccharomyces cerevisiae Wss1 protein is only present in mother cells.  

Science.gov (United States)

The Saccharomyces cerevisiae WSS1 (Weak Suppressor of Smt3) gene has initially been identified as a multicopy suppressor of a mutation in SMT3 encoding the small ubiquitin-like modifier. Later, multiple functions related to DNA replication and repair have been found for WSS1. Here, we report the subcellular location of the Wss1 protein. Fluorescence microscopy of strains expressing a Wss1p-green fluorescent protein (GFP) fusion shows that the protein is present in a single sharp spot near the nuclear membrane, distinct from the spindle pole bodies and nucleolus. In dividing cells, the spot is exclusively present in the mother cell, suggesting a mother cell-specific function of WSS1. PMID:18336552

van Heusden, G Paul H; Steensma, H Yde

2008-05-01

324

The identification of a gene family in the Saccharomyces cerevisiae ergosterol biosynthesis pathway.  

Science.gov (United States)

The Saccharomyces cerevisiae ERG24 gene, encoding sterol delta 14 reductase (Erg24p), was cloned by selecting strains carrying sequences on a 2 mu-based vector for resistance to the morpholine fungicide, fenpropimorph (Fp). Four distinct plasmid inserts which conferred Fp resistance (FpR) were recovered (plasmids pML99, pML100, pML101 and pM103). Although Fp is reported to inhibit activity of Erg24p and sterol delta 8-delta 7 isomerase (Erg2p; encoded by ERG2), none of the inserts had restriction maps resembling ERG2. In addition, a 2 mu plasmid overexpression of the ERG2 sequence did not produce FpR. Characterization studies were focused on plasmid pML100, because it was the only plasmid to confer FpR consistently when tested in a number of different genetic backgrounds. Tests with a panel of fungicides indicated that pML100 conferred significant resistance only to compounds (Fp, tridemorph, fenpropidin and azasterol) which have a shared site of action, Erg24p. An insertional disruption of pML100 resulted in an obligate anaerobic phenotype, indicating a lesion in sterol biosynthesis. Sterol analysis of the disrupted mutant demonstrated the accumulation of ignosterol, indicating a loss of Erg24p activity. A SphI-XbaI fragment of pML100 was sequenced, revealing the presence of an ORF encoding a 438-amino-acid protein, which is highly similar to those encoded by two previously reported yeast drug sensitivity genes, sts1+ (Schizosaccharomyces pombe) and YGL022 (S. cerevisiae). Analyses of these genes demonstrated that strains carrying disruptions of sts1+ or YGL022 have ergosterol biosynthesis defects in the enzyme, sterol C-24(28) reductase (Erg4p; encoded by ERG4).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8125337

Lai, M H; Bard, M; Pierson, C A; Alexander, J F; Goebl, M; Carter, G T; Kirsch, D R

1994-03-11

325

[Saccharomyces cerevisiae fungemia in an elderly patient following probiotic treatment].  

Science.gov (United States)

Saccharomyces cerevisiae, known as baker's yeast, is also used as a probiotic agent to treat gastroenteritis by modulating the endogenous flora and immune system. However, since there have been increasing reports of fungemia due to S.cerevisiae and its subspecies S.boulardii, it is recommended that probiotics should be cautiously used in immunosuppressed patients, people with underlying diseases and low-birth weight babies. To emphasize this phenomenon, in this report, a case of S.cerevisiae fungemia developed in a patient given probiotic treatment for antibiotic-associated diarrhea, was presented. An 88-year-old female patient was admitted to our hospital with left hip pain, hypotension, and confusion. Her medical history included hypertension, chronic renal failure, left knee replacement surgery, and recurrent urinary tract infections due to neurogenic bladder. She was transferred to the intensive care unit with the diagnosis of urosepsis. After obtaining blood and urine samples for culture, empirical meropenem (2 x 500 mg) and linezolid (1 x 600 mg) treatment were administered. A central venous catheter (CVC) was inserted and after one day of inotropic support, her hemodynamic parameters were stabilized. The urine culture obtained on admission yielded extended-spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli. Urine culture was repeated after three days and no bacteria were isolated. On the 4th day of admission she developed diarrhea. Toxin A/B tests for Clostridium difficile were negative. To relieve diarrhea, S.boulardii (Reflor 250 mg capsules, Sanofi Aventis, Turkey) was administered twice a day, without opening capsules. Two days later, her C-reactive protein (CRP) level increased from 23.2 mg/L to 100 mg/L without fever. Her blood culture taken from the CVC yielded S.cerevisiae. Linezolid and meropenem therapies were stopped on the 13th and 14th days, respectively, while prophylactic fluconazole therapy was replaced with caspofungin 1 x 50 mg on the fifth day. After seven days of therapy CRP and serum creatinine levels decreased to 9.1 mg/L and 1.2 mg/dl, respectively; and she was discharged from the hospital with improvement. The probiotic capsules were used unopen, thus, it was proposed that S.cerevisiae fungemia originated from translocation from the intestinal mucosa. Since it was not possible to investigate the molecular genetics of the strain isolated from the blood culture and the strain present in the probiotic, a definite conclusion about the origin of the strain could not be reached. It was thought that old age and underlying disease of the patient were the related predisposing factors for S.cerevisiae fungemia. This case emphasized that clinicians should be cautious in case of probiotic application even though in encapsulated form, even in immunocompetent patients with a history of long-term hospital stay and use of broad-spectrum antimicrobials since there may be a risk of S.cerevisiae fungemia development. PMID:24819274

Eren, Zehra; Gurol, Ye?im; Sonmezoglu, Meral; Eren, Hatice Seyma; Celik, Gülden; Kantarci, Gülçin

2014-04-01

326

ACÚMULO DE CÁDMIO POR Saccharomyces cerevisiae FERMENTANDO MOSTO DE MELAÇO  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 esterili [...] zado, 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. Abstract in english 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 s [...] ugars (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.

L.G. do, PRADO-FILHO; R.N., DOMINGOS; S.M.G. da, SILVA.

1998-01-01

327

ACÚMULO DE CÁDMIO POR Saccharomyces cerevisiae FERMENTANDO MOSTO DE MELAÇO  

Directory of Open Access Journals (Sweden)

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.

L.G. do PRADO-FILHO

1998-01-01

328

Septins localize to microtubules during nutritional limitation in Saccharomyces cerevisiae  

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Full Text Available Abstract Background In Saccharomyces cerevisiae, nutrient limitation stimulates diploid cells to undergo DNA replication and meiosis, followed by the formation of four haploid spores. Septins are a family of proteins that assemble a ring structure at the mother-daughter neck during vegetative growth, where they control cytokinesis. In sporulating cells, the septin ring disassembles and septins relocalize to the prospore membrane. Results Here, we demonstrate that nutrient limitation triggers a change in the localization of at least two vegetative septins (Cdc10 and Cdc11 from the bud neck to the microtubules. The association of Cdc10 and Cdc11 with microtubules persists into meiosis, and they are found associated with the meiotic spindle until the end of meiosis II. In addition, the meiosis-specific septin Spr28 displays similar behavior, suggesting that this is a common feature of septins. Septin association to microtubules is a consequence of the nutrient limitation signal, since it is also observed when haploid cells are incubated in sporulation medium and when haploid or diploid cells are grown in medium containing non-fermentable carbon sources. Moreover, during meiosis II, when the nascent prospore membrane is formed, septins moved from the microtubules to this membrane. Proper organization of the septins on the membrane requires the sporulation-specific septins Spr3 and Spr28. Conclusion Nutrient limitation in S. cerevisiae triggers the sporulation process, but it also induces the disassembly of the septin bud neck ring and relocalization of the septin subunits to the nucleus. Septins remain associated with microtubules during the meiotic divisions and later, during spore morphogenesis, they are detected associated to the nascent prospore membranes surrounding each nuclear lobe. Septin association to microtubules also occurs during growth in non-fermentable carbon sources.

Vázquez de Aldana Carlos R

2008-10-01

329

Divergence of the mitochondrial leucyl tRNA synthetase genes in two closely related yeasts Saccharomyces cerevisiae and Saccharomyces douglasii: a paradigm of incipient evolution.  

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We studied the NAM2 genes of Saccharomyces douglasii and Saccharomyces cerevisiae, and showed that they are interchangeable for all the known functions of these genes, both mitochondrial protein synthesis and mitochondrial mRNA splicing. This confirms the prediction that the S. douglasii NAM2D gene encodes the mitochondrial leucyl tRNA synthetase (EC 6.1.1.4.). The observation that these enzymes are interchangeable for their mRNA splicing functions, even though there are significant differences in the intron/exon structure of their mitochondrial genome, suggests that they may have a general role in yeast mitochondrial RNA splicing. A short open reading frame (ORF) precedes the synthetase-encoding ORF, and we showed that at least in S. cerevisiae this is not essential for the expression of the gene; however, it may be involved in a more subtle type of regulation. Sequence comparisons of S. douglasii and S. cerevisiae revealed a particularly interesting situation from the evolutionary point of view. It appears that the two yeasts have diverged relatively recently: there is remarkable nucleotide sequence conservation, with no deletions or insertions, but numerous (albeit non-saturating) silent substitutions resulting from transitions. This applies not only to the NAM2 coding regions, but also to two other ORFs flanking the NAM2 ORF. The regions between the ORFs (believed to be intergenic regions) are much less conserved, with several deletions and insertions. Thus S. douglasii and S. cerevisiae provide an ideal system for the study of molecular evolution, being two yeasts "caught in the act" of speciation. PMID:3054483

Herbert, C J; Dujardin, G; Labouesse, M; Slonimski, P P

1988-08-01

330

Novel interaction of the Hsp90 chaperone machine with Ssl2, an essential DNA helicase in Saccharomyces cerevisiae  

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Hsp90 is an essential molecular chaperone that is critical for the activity of diverse cellular proteins. Hsp90 functions with a number of co-chaperone proteins, including Sti1/Hop. We conducted a genetic screen in Saccharomyces cerevisiae to isolate mutations that exhibit enhanced growth defects in the absence of STI1. We obtained mutations in genes encoding components of the Hsp90 chaperone machine, HSC82, CPR7 and YDJ1, and two essential genes, SSL2 and UTP21, not previously linked to Hsp9...

Flom, Gary; Weekes, Jared; Johnson, Jill L.

2005-01-01

331

A glycolytic enzyme, enolase, is recruited as a cofactor of tRNA targeting toward mitochondria in Saccharomyces cerevisiae  

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In many organisms, mitochondria import nuclear DNA-encoded small RNAs. In yeast Saccharomyces cerevisiae, one out of two cytoplasmic isoacceptor tRNAsLys is partially addressed into the organelle. Mitochondrial targeting of this tRNA was shown to depend on interaction with the precursor of mitochondrial lysyl–tRNA synthetase, preMsk1p. However, preMsk1p alone was unable to direct tRNA targeting, suggesting the existence of additional protein factor(s). Here, we identify the glycolytic enzym...

Entelis, Nina; Brandina, Irina; Kamenski, Piotr; Krasheninnikov, Igor A.; Martin, Robert P.; Tarassov, Ivan

2006-01-01

332

Rtr1 Is the Saccharomyces cerevisiae Homolog of a Novel Family of RNA Polymerase II-Binding Proteins?  

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Cells must rapidly sense and respond to a wide variety of potentially cytotoxic external stressors to survive in a constantly changing environment. In a search for novel genes required for stress tolerance in Saccharomyces cerevisiae, we identified the uncharacterized open reading frame YER139C as a gene required for growth at 37°C in the presence of the heat shock mimetic formamide. YER139C encodes the closest yeast homolog of the human RPAP2 protein, recently identified as a novel RNA poly...

Gibney, Patrick A.; Fries, Thomas; Bailer, Susanne M.; Morano, Kevin A.

2008-01-01

333

Improved ethanol fermentation by heterologous endoinulinase and inherent invertase from inulin by Saccharomyces cerevisiae.  

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It is hypothesized that introduction of an endoinulinase gene into Saccharomyces cerevisiae will improve its inulin utilization and ethanol fermentation through collaboration between the heterologous endoinulinase and the inherent invertase SUC2. The aim of this work was to test the hypothesis by introducing the endoinulinase gene inuA from Aspergillus niger into S. cerevisiae. The results showed that heterologous inuA expressed in S. cerevisiae selectively digested long chains of inulin into short fructooligosaccharides and parts of these fructooligosaccharides could be efficiently utilized by the yeast. This study demonstrated that collaboration between heterologous endoinulinase and inherent invertase improved inulin degradation and ethanol fermentation in S. cerevisiae. PMID:23683966

Yuan, Bo; Wang, Shi-An; Li, Fu-Li

2013-07-01

334

Killed Saccharomyces cerevisiae protects against lethal challenge of Cryptococcus grubii.  

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Heat-killed Saccharomyces cerevisiae (HKY) vaccination protects mice against aspergillosis, coccidioidomycosis, mucormycosis, or candidiasis. We studied HKY protection against murine cryptococcosis. Once weekly subcutaneous HKY doses (S, 6 × 10(7); 2S, 1.2 × 10(8); 3S, 2.4 × 10(8)) began 28 (×3), 35 (×4), or 42 (×6) days prior to intravenous Cryptococcus grubii infection. Survival through 28 days, and CFU in the organs of survivors, were compared to saline-vaccinated controls. In the initial experiment, S, S×4, or 2S reduced brain CFU; liver or spleen CFU was reduced by S×4 or 2S. In a more lethal second experiment, 2S×6, 2S, or 3S×4 improved survival, and HKY regimens reduced CFU in the brain, liver, or spleen, with 2S×6, 2S, or 3S×4 most efficacious. Dose size appears more important than the number of doses: Regimens >S were superior, and 2S and 2S×6 were equivalent. 2S and 3S were equivalent, suggesting doses >2S do not provide additional protection. HKY protects against Cryptococcus, supporting components of HKY as a basis for the development of a panfungal vaccine. PMID:25118873

Majumder, Tanya; Liu, Min; Chen, Vicky; Martinez, Marife; Alvarado, Danielle; Clemons, Karl V; Stevens, David A

2014-10-01

335

Calcium dependence of eugenol tolerance and toxicity in Saccharomyces cerevisiae.  

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Eugenol is a plant-derived phenolic compound which has recognised therapeutical potential as an antifungal agent. However little is known of either its fungicidal activity or the mechanisms employed by fungi to tolerate eugenol toxicity. A better exploitation of eugenol as a therapeutic agent will therefore depend on addressing this knowledge gap. Eugenol initiates increases in cytosolic Ca2+ in Saccharomyces cerevisiae which is partly dependent on the plasma membrane calcium channel, Cch1p. However, it is unclear whether a toxic cytosolic Ca2+elevation mediates the fungicidal activity of eugenol. In the present study, no significant difference in yeast survival was observed following transient eugenol treatment in the presence or absence of extracellular Ca2+. Furthermore, using yeast expressing apoaequorin to report cytosolic Ca2+ and a range of eugenol derivatives, antifungal activity did not appear to be coupled to Ca2+ influx or cytosolic Ca2+ elevation. Taken together, these results suggest that eugenol toxicity is not dependent on a toxic influx of Ca2+. In contrast, careful control of extracellular Ca2+ (using EGTA or BAPTA) revealed that tolerance of yeast to eugenol depended on Ca2+ influx via Cch1p. These findings expose significant differences between the antifungal activity of eugenol and that of azoles, amiodarone and carvacrol. This study highlights the potential to use eugenol in combination with other antifungal agents that exhibit differing modes of action as antifungal agents to combat drug resistant infections. PMID:25036027

Roberts, Stephen K; McAinsh, Martin; Cantopher, Hanna; Sandison, Sean

2014-01-01

336

Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

337

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

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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

Feng, Xueyang; Lian, Jiazhang; Zhao, Huimin

2015-01-01

338

Degradation signals for ubiquitin system proteolysis in Saccharomyces cerevisiae.  

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Combinations of different ubiquitin-conjugating (Ubc) enzymes and other factors constitute subsidiary pathways of the ubiquitin system, each of which ubiquitinates a specific subset of proteins. There is evidence that certain sequence elements or structural motifs of target proteins are degradation signals which mark them for ubiquitination by a particular branch of the ubiquitin system and for subsequent degradation. Our aim was to devise a way of searching systematically for degradation signals and to determine to which ubiquitin system subpathways they direct the proteins. We have constructed two reporter gene libraries based on the lacZ or URA3 genes which, in Saccharomyces cerevisiae, express fusion proteins with a wide variety of C-terminal extensions. From these, we have isolated clones producing unstable fusion proteins which are stabilized in various ubc mutants. Among these are 10 clones whose products are stabilized in ubc6, ubc7 or ubc6ubc7 double mutants. The C-terminal extensions of these clones, which vary in length from 16 to 50 amino acid residues, are presumed to contain degradation signals channeling proteins for degradation via the UBC6 and/or UBC7 subpathways of the ubiquitin system. Some of these C-terminal tails share similar sequence motifs, and a feature common to almost all of these sequences is a highly hydrophobic region such as is usually located inside globular proteins or inserted into membranes. PMID:9582269

Gilon, T; Chomsky, O; Kulka, R G

1998-05-15

339

Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.  

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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

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

340

Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae  

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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.

Hou, Jin; Lages, Nuno

2009-01-01

 
 
 
 
341

Engineering chimeric thermostable GH7 cellobiohydrolases in Saccharomyces cerevisiae.  

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We report here the effect of adding different types of carbohydrate-binding modules (CBM) to a single-module GH7 family cellobiohydrolase Cel7A from a thermophilic fungus Talaromyces emersonii (TeCel7A). Both bacterial and fungal CBMs derived from families 1, 2 and 3, all reported to bind to crystalline cellulose, were used. Chimeric cellobiohydrolases with an additional S-S bridge in the catalytic module of TeCel7A were also made. All the fusion proteins were secreted in active form and in good yields by Saccharomyces cerevisiae. The purified chimeric enzymes bound to cellulose clearly better than the catalytic module alone and demonstrated high thermal stability, having unfolding temperatures (T m) ranging from 72 °C to 77 °C. The highest activity enhancement on microcrystalline cellulose could be gained by a fusion with a bacterial CBM3 derived from Clostridium thermocellum cellulosomal-scaffolding protein CipA. The two CBM3 fusion enzymes tested were more active than the reference enzyme Trichoderma reesei Cel7A both at moderate (45 °C and 55 °C) and at high temperatures (60 °C and 65 °C), the hydrolysis yields being two- to three-fold better at 60 °C, and six- to seven-fold better at 65 °C. The best enzyme variant was also tested on a lignocellulosic feedstock hydrolysis, which demonstrated its potency in biomass hydrolysis even at 70 °C. PMID:23974371

Voutilainen, Sanni P; Nurmi-Rantala, Susanna; Penttilä, Merja; Koivula, Anu

2014-04-01

342

Heterologous Expression of Syntaxin 6 in Saccharomyces cerevisiae  

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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

MARTIN GÖTTE

2002-01-01

343

Bioflavour production from orange peel hydrolysate using immobilized Saccharomyces cerevisiae.  

Science.gov (United States)

The rising trend of bioflavour synthesis by microorganisms is hindered by the high manufacturing costs, partially attributed to the cost of the starting material. To overcome this limitation, in the present study, dilute-acid hydrolysate of orange peel was employed as a low-cost, rich in fermentable sugars substrate for the production of flavour-active compounds by Saccharomyces cerevisiae. With this purpose, the use of immobilized cell technology to protect cells against the various inhibitory compounds present in the hydrolysate was evaluated with regard to yeast viability, carbon and nitrogen consumption and cell ability to produce flavour active compounds. For cell immobilization the encapsulation in Ca alginate beads was used. The results were compared with those obtained using free-cell system. Based on the data obtained immobilized cells showed better growth performance and increased ability for de novo synthesis of volatile esters of "fruity" aroma (phenylethyl acetate, ethyl hexanoate, octanoate, decanoate and dodecanoate) than those of free cells. The potential for in situ production of new formulations containing flavour-active compounds derive from yeast cells and also from essential oil of orange peel (limonene, ?-terpineol) was demonstrated by the fact that bioflavour mixture was found to accumulate within the beads. Furthermore, the ability of the immobilized yeast to perform efficiently repeated batch fermentations of orange peel hydrolysate for bioflavour production was successfully maintained after six consecutive cycles of a total period of 240 h. PMID:23995224

Lalou, Sofia; Mantzouridou, Fani; Paraskevopoulou, Adamantini; Bugarski, Branko; Levic, Steva; Nedovic, Victor

2013-11-01

344

Passage through stationary phase advances replicative aging in Saccharomyces cerevisiae  

Science.gov (United States)

Saccharomyces cerevisiae mother cells undergo an aging program that includes morphologic changes, sterility, redistribution of the Sir transcriptional silencing complex from HM loci and telomeres to the nucleolus, alterations in nucleolar architecture, and accumulation of extrachromosomal ribosomal DNA circles (ERCs). We report here that cells starved for nutrients during prolonged periods in stationary phase show a decrease in generational lifespan when they reenter the cell cycle. This shortened lifespan is not transmitted to progeny cells, indicating that it is not due to irreversible genetic damage. The decrease in the lifespan is accompanied by all of the changes of accelerated aging with the notable exception that ERC accumulation is not augmented compared with generation-matched, nonstarved cells. These results suggest a number of models, including one in which starvation reveals a component of aging that works in parallel with the accumulation of ERCs. Stationary-phase yeast cells may be a useful system for identifying factors that affect aging in other nondividing eukaryotic cells. PMID:10430902

Ashrafi, Kaveh; Sinclair, David; Gordon, Jeffrey I.; Guarente, Leonard

1999-01-01

345

Antimutators of mitochodrial and nuclear DNA in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

In Saccharomyces cerevisiae ten antimutator mutants have been isolated. The spontaneous occurrence of mitochondrial mutants resistant to erythromycin, oligomycin, and diuron is decreased 2-60-fold in these strains. The rate of forward and reverse spontaneous mutations of the nuclear genome is also reduced. The meiotic progenies arising from the crosses of seven mutants (LB1, LB2, LB4, LB5, LB6, LB7, LB10) with an isogenic parental strain exhibit 2:2 segregations and therefore are the result of mutations in a single nuclear gene. The six mutants LB1, LB2, LB4, LB6, LB7, LB10 are semidominant and determine six complementation groups. The mutant LB5 is dominant and therefore cannot be assigned to any complementation group. The mutants. LB1, LB4 and LB10 are gamma-ray sensitive and, by tetrad analysis, it has been shown that gamma-ray sensitivity and spontaneous antimutability are the result of a single nuclear gene mutation. The other three mutants LB3, LB8 and LB9 exhibit complex tetrad segregations, typical of cytoplasmic inheritance and do not complement each other. However, although the mutations are semidominant, it has not been possible to detect any antimutator cytoductant among some 500 cytoductants carrying the karl 1-1 nucleus. (orig./AJ)ng the karl 1-1 nucleus. (orig./AJ)

346

Biosynthesis of diphthamide in the yeast Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Inactivation of EF-2 by diphtheria toxin requires the presence of a posttranslationally synthesized amino acid residue, diphthamide. The present work was undertaken to study the biosynthetic mechanism of diphthamide synthesis in the yeast Saccharomyces cerevisiae in order to gain better understanding of the biological roles of this unique amino acid residue. Thirty-one haploid ADP-ribosylation-negative mutants, comprising 5 complementation groups, were obtained. One of these mutants contains a toxin-resistant form of EF-2 which can be converted to a toxin-sensitive form through the methylation reaction catalyzed by a S-AdoMet:EF-2 methyltransferase enzyme which is present in other yeast strains. The [3He]methylated residue in the EF-2 modified by the methyltransferase in the presence of S-Ado-L-[3H-methyl]-Met has been analyzed chromatographically following both acid and enzymatic hydrolysis. At the conclusion of the reaction, all of the radiolabel was recovered as diphthine (the unamidated form of diphthamide). The authors conclude that the S-AdoMet:EF-2-methyltransferase is specific for the addition of at least the last two of the three methyl groups present in diphthine

347

Biosynthesis of diphthamide in the yeast Saccharomyces cerevisiae  

Energy Technology Data Exchange (ETDEWEB)

Inactivation of EF-2 by diphtheria toxin requires the presence of a posttranslationally synthesized amino acid residue, diphthamide. The present work was undertaken to study the biosynthetic mechanism of diphthamide synthesis in the yeast Saccharomyces cerevisiae in order to gain better understanding of the biological roles of this unique amino acid residue. Thirty-one haploid ADP-ribosylation-negative mutants, comprising 5 complementation groups, were obtained. One of these mutants contains a toxin-resistant form of EF-2 which can be converted to a toxin-sensitive form through the methylation reaction catalyzed by a S-AdoMet:EF-2 methyltransferase enzyme which is present in other yeast strains. The (/sup 3/He)methylated residue in the EF-2 modified by the methyltransferase in the presence of S-Ado-L-(/sup 3/H-methyl)-Met has been analyzed chromatographically following both acid and enzymatic hydrolysis. At the conclusion of the reaction, all of the radiolabel was recovered as diphthine (the unamidated form of diphthamide). The authors conclude that the S-AdoMet:EF-2-methyltransferase is specific for the addition of at least the last two of the three methyl groups present in diphthine.

Chen, J.Y.C.

1985-01-01

348

Global optimization of the Saccharomyces cerevisiae: fermentation process.  

Science.gov (United States)

In this article, steady-state optimization of the Saccharomyces cerevisiae fermentation process problem is performed revealing the existence of multiple optimum solutions. The globally optimum solution was determined using the NEOS global optimization solver LINDO. A branch and bound strategy (bnb20.m) and the global search and multistart algorithms in the MATLAB global optimization toolbox were successful in determining locally optimum solutions and these results are validated by plotting the objective function against the decision variables. While in some cases all the strategies were successful in obtaining the globally optimum solutions, an example is presented where the most beneficial product value, which is not a stationary point and lies on the feasible boundary, is obtained by the LINDO global optimization solver (but not the other routines) as the globally optimum solution. The Jones-Kompala model was used to model the steady-state of the fermentation process. While several articles have been published demonstrating the existence of nonlinearities and bifurcations in this model, the challenges posed by this model to optimization has never been investigated so far and this work attempts to do so. Both dilution rate and the oxygen mass transfer coefficient were used as the decision variables individually and together. PMID:23780907

Sridhar, Lakshmi N

2013-01-01

349

Post-Transcriptional Regulation of Iron Homeostasis in Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

Full Text Available Iron is an essential micronutrient for all eukaryotic organisms because it participates as a redox cofactor in a wide variety of biological processes. Recent studies in Saccharomyces cerevisiae have shown that in response to iron deficiency, an RNA-binding protein denoted Cth2 coordinates a global metabolic rearrangement that aims to optimize iron utilization. The Cth2 protein contains two Cx8Cx5Cx3H tandem zinc fingers (TZFs that specifically bind to adenosine/uridine-rich elements within the 3' untranslated region of many mRNAs to promote their degradation. The Cth2 protein shuttles between the nucleus and the cytoplasm. Once inside the nucleus, Cth2 binds target mRNAs and stimulates alternative 3' end processing. A Cth2/mRNA-containing complex is required for export to the cytoplasm, where the mRNA is degraded by the 5' to 3' degradation pathway. This post-transcriptional regulatory mechanism limits iron utilization in nonessential pathways and activates essential iron-dependent enzymes such as ribonucleotide reductase, which is required for DNA synthesis and repair. Recent findings indicate that the TZF-containing tristetraprolin protein also functions in modulating human iron homeostasis. Elevated iron concentrations can also be detrimental for cells. The Rnt1 RNase III exonuclease protects cells from excess iron by promoting the degradation of a subset of the Fe acquisition system when iron levels rise.

Antonia María Romero

2013-07-01

350

Effects of low X-ray doses in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Three strains of Saccharomyces cerevisiae with different capacities for repair of radiation damage (RAD, rad18, and rad52) have been tested for their colony forming ability (CFA) and growth rates after application of small X-ray doses from 3.8 mGy to 40 Gy. There was no reproducible increase in CFA observable after application of doses between 3.8 mGy and 4.7 Gy.X-ray doses of 40 Gy causing an inactivation of CFA from 90% to 50%, depending on the repair capacity of the strains used, caused a reduced increase in optical density during 2 h buffer treatment in comparison to unirradiated cells. This reduction however, is reversible as soon as the cells are transferred into nutrient medium. One hour after transfer into growh medium the portions of cells with large buds (Gs and M phase) and cells with small buds (S phase) are drastically different in irradiated cells from those obtained in unirradiated cells. The time necessary for separation of mother and daughter cells is prolonged by X-ray irradiation and the formation of new buds is retarded. (orig.)

351

MAP kinase pathways in the yeast Saccharomyces cerevisiae  

Science.gov (United States)

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.

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

1998-01-01

352

[Improving ergosterol production from molasses by Saccharomyces cerevisiae].  

Science.gov (United States)

Ergosterol is an economically important metabolite produced by yeast. To improve the production of ergosterol by Saccharomyces cerevisiae YEH56 (pHXA42) from molasses, a cheap and regenerative material, different strategies were applied. First, Plackett-Burman design and central composite design were applied to screen the significant factors in fermentation medium using ergosterol yield (g/L) as the response value. Ergosterol yield reached 371.56 mg/L by using the optimal fermentation medium in shake-flask culture (total sugar in molasses 40 g/L, KH2PO4 1 g/L, K2HPO4 1.86 g/L, CuSO4 x 5H2O 17.5 mg/L, FeSO4 x 7H2O 13.9 mg/L, MgSO4 x 5H2O 12.3 mg/L, corn steep liquor 10 mL/L), which was increased by 29.5% compared with the initial culture. Second, ergosterol yield was increased by 62.1% using a pH-control strategy in a 5-L bioreactor. Third, ergosterol production was improved further by using molasses feeding strategy. After 38 h fermentation, ergosterol yield reached 1 953.85 mg/L, which was 3.2 times of that in batch fermentation. Meanwhile, ergosterol production rate was increased by 42.7% compared with that in the batch culture. PMID:24701833

Wang, Shaojie; Guo, Xuena; He, Xiuping; Zhang, Borun

2013-11-01

353

Spontaneous and radiation induced gene conversion in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Spontaneous and radiation induced gene conversion to arginine independence was studied in a heteroallelic diploid strain of yeast Saccharomyces cerevisiae BZ 34. When stationary phase cells were incubated in phosphate buffer (pH7) at 300C under aerated condition for 48 hours, the conversion frequency increased by a factor of about 1000 times the background. This was found to be so even when the cells were incubated in saline (0.85%) or distilled water. Various conditions influencing this enhancement have been investigated. Conversion frequency enhancement was not significant under anoxic conditions and was absent at low temperatures and in log phase cells. Caffeine could inhibit this enhancement when present in the suspension medium. These results can be explained on the basis of the induction of meiosis in cells held in buffer. Microscopic examination confirmed this view. Under conditions not favourable for the onset of meiosis there is no significant enhancement in conversion frequency. In stationary phase cells exposed to series of gamma doses, the conversion frequency increases with dose. Post irradiation incubation in buffer further increases the conversion frequency. However, the increase expressed as the ratio of the conversion frequency on buffer holding to that on immediate plating decreased with increasing dose. This decrease in enhancement with increasing dose may be due to the dose dependent inhibition of meiosis. (author)nhibition of meiosis. (author)

354

Thermal aspects of biological effects of microwaves in Saccharomyces cerevisiae.  

Science.gov (United States)

The formation of zygotes between two haploid strains of yeast (Saccharomyces cerevisiae) was determined under treatment with microwaves of 9.4 and 17 GHz at power levels up to 50 and 60 mW/cm2 and a specific absorption rate below 24 mW/g, or with conventional heating. Microwave treatments at 9.4 GHz or 17 GHz at a power density of 10 mW/cm2 produced an increase in zygote formation equivalent to that produced by conventional heating in an incubator, i.e. equivalent to a rise in temperature of 0.5 or 1 degrees C. At higher power densities zygote formation was slightly increased by microwaves at 17 GHz as compared to microwaves at 9.4 GHz probably due to the higher absorption of microwaves at 17 GHz by intracellular water molecules. Under these conditions, microwaves had no effect on cell survival or the induction of cytoplasmic 'petite' mutations. PMID:3905665

Dardalhon, M; Averbeck, D; Berteaud, A J; Ravary, V

1985-12-01

355

Dynamic regulation of mitochondrial respiratory chain efficiency in Saccharomyces cerevisiae.  

Science.gov (United States)

To adapt to changes in the environment, cells have to dynamically alter their phenotype in response to, for instance, temperature and oxygen availability. Interestingly, mitochondrial function in Saccharomyces cerevisiae is inherently temperature sensitive; above 37 °C, yeast cells cannot grow on respiratory carbon sources. To investigate this phenomenon, we studied the effect of cultivation temperature on the efficiency (production of ATP per atom of oxygen consumed, or P/O) of the yeast respiratory chain in glucose-limited chemostats. We determined that even though the specific oxygen consumption rate did not change with temperature, oxygen consumption no longer contributed to mitochondrial ATP generation at temperatures higher than 37 °C. Remarkably, between 30 and 37 °C, we observed a linear increase in respiratory efficiency with growth temperature, up to a P/O of 1.4, close to the theoretical maximum that can be reached in vivo. The temperature-dependent increase in efficiency required the presence of the mitochondrial glycerol-3-phosphate dehydrogenase GUT2. Respiratory chain efficiency was also altered in response to changes in oxygen availibility. Our data show that, even in the absence of alternative oxidases or uncoupling proteins, yeast has retained the ability to dynamically regulate the efficiency of coupling of oxygen consumption to proton translocation in the respiratory chain in response to changes in the environment. PMID:21964735

Postmus, Jarne; Tuzun, I?il; Bekker, Martijn; Müller, Wally H; de Mattos, M Joost Teixeira; Brul, Stanley; Smits, Gertien J

2011-12-01

356

BIOTECHNOLOGICAL PRODUCTION OF ETHANOL BY SACCHAROMYCES CEREVISIAE, USING DIFFERENT SUBSTRATES  

Directory of Open Access Journals (Sweden)

Full Text Available Research efforts are needed to design and improve the process, which would produce sustainable and economically feasible transportation fuel. The present investigation was undertaken to determine the availability of carbohydrates in hydrolysates derived from different substrates Acacia arabica, Delbergia sisso, Peltophorum Pterocarpur and Perkia biglobosa pods, in the production of ethanol. The enzymatic hydrolysis of the substrates has yielded the significant amount of reducing sugar from the substrates by comparing the effect of enzymes on hydrolysis. The Acacia arabica pods has showed the higher production of reducing sugars when treated with 4% a-amylase whereas Peltophorum pterocarpum has produced lowest yield of reducing sugar at 4% a-amylase enzyme. The optimum temperature required for the activity of a-amylase enzyme in the production of reducing sugars using different substrates were revealed that at 30oC the Acacia arabica has yielded maximum sugars whereas the Perkia biglobosa has showed the minimum yield of reducing sugar. The optimum period of enzyme activity in the production of reducing sugars using different substrates was indicted that the Acacia arabica has showed the maximum yield of reducing sugars during the incubation period of 24 hours whereas minimum yield was observed in Perkia biglobosa. The optimum incubation period of Saccharomyces cerevisiae in the production of ethanol has showed that the seven days of incubation has yielded maximum amount of ethanol using the substrate Acacia arabica.

Vijaya S. Gulalkayi

2012-12-01

357

Metabolic engineering of Saccharomyces cerevisiae for production of ginsenosides.  

Science.gov (United States)

Ginsenosides are the primary bioactive components of ginseng, which is a popular medicinal herb and exhibits diverse pharmacological activities. Protopanaxadiol is the aglycon of several dammarane-type ginsenosides, which also has anticancer activity. For microbial production of protopanaxadiol, dammarenediol-II synthase and protopanaxadiol synthase genes of Panax ginseng, together with a NADPH-cytochrome P450 reductase gene of Arabidopsis thaliana, were introduced into Saccharomyces cerevisiae, resulting in production of 0.05 mg/g DCW protopanaxadiol. Increasing squalene and 2,3-oxidosqualene supplies through overexpressing truncated 3-hydroxyl-3-methylglutaryl-CoA reductase, farnesyl diphosphate synthase, squalene synthase and 2,3-oxidosqualene synthase genes, together with increasing protopanaxadiol synthase activity through codon optimization, led to 262-fold increase of protopanaxadiol production. Finally, using two-phase extractive fermentation resulted in production of 8.40 mg/g DCW protopanaxadiol (1189 mg/L), together with 10.94 mg/g DCW dammarenediol-II (1548 mg/L). The yeast strains engineered in this work can serve as the basis for creating an alternative way for production of ginsenosides in place of extraction from plant sources. PMID:24126082

Dai, Zhubo; Liu, Yi; Zhang, Xianan; Shi, Mingyu; Wang, Beibei; Wang, Dong; Huang, Luqi; Zhang, Xueli

2013-11-01

358

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

Directory of Open Access Journals (Sweden)

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.

L.V. FERREIRA

1999-01-01

359

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

1999-01-01

360

Identification of the copper regulon in Saccharomyces cerevisiae by DNA microarrays.  

Science.gov (United States)

In Saccharomyces cerevisiae, copper ions regulate gene expression through the two transcriptional activators, Ace1 and Mac1. Ace1 mediates copper-induced gene expression in cells exposed to stressful levels of copper salts, whereas Mac1 activates a subset of genes under copper-deficient conditions. DNA microarray hybridization experiments revealed a limited set of yeast genes differentially expressed under growth conditions of excess copper or copper deficiency. Mac1 activates the expression of six S. cerevisiae genes, including CTR1, CTR3, FRE1, FRE7, YFR055w, and YJL217w. Two of the last three newly identified Mac1 target genes have no known function; the third, YFR055w, is homologous to cystathionine gamma-lyase encoded by CYS3. Several genes that are differentially expressed in cells containing a constitutively active Mac1, designated Mac1(up1), are not direct targets of Mac1. Induction or repression of these genes is likely a secondary effect of cells because of constitutive Mac1 activity. Elevated copper levels induced the expression of the metallothioneins CUP1 and CRS5 and two genes, FET3 and FTR1, in the iron uptake system. Copper-induced FET3 and FTR1 expression arises from an indirect copper effect on cellular iron pools. PMID:10922376

Gross, C; Kelleher, M; Iyer, V R; Brown, P O; Winge, D R

2000-10-13

 
 
 
 
361

Localization of nuclear retained mRNAs in Saccharomyces cerevisiae  

DEFF Research Database (Denmark)

In the yeast Saccharomyces cerevisiae, a common conditional phenotype associated with deletion or mutation of genes encoding mRNA export factors is the rapid accumulation of mRNAs in intranuclear foci, suggested to be near transcription sites. The nuclear RNA exosome has been implicated in retaining RNAs in these foci; on deletion of the exosome component Rrp6p, the RNA is released. To determine the exact nuclear location of retained as well as released mRNAs, we have used mRNA export mutant strains to analyze the spatial relationship between newly synthesized heat shock mRNA, the chromosomal site of transcription, and known S. cerevisiae nuclear structures such as the nucleolus and the nucleolar body. Our results show that retained SSA4 RNA localizes to an area in close proximity to the SSA4 locus. On deletion of Rrp6p and release from the genomic locus, heat shock mRNAs produced in the rat7–1 strain colocalize predominantly with nucleolar antigens. Bulk poly(A)+ RNA, on the other hand, is localized primarily to the nuclear rim. Interestingly, the RNA binding nucleocytoplasmic shuttle protein Npl3p shows strong colocalization with bulk poly(A)+ RNA, regardless of its nuclear location. Taken together, our data show that retention occurs close to the gene and indicate distinct nuclear fates of different mRNAs.

Thomsen, Rune; Libri, Domenico

2003-01-01

362

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

Science.gov (United States)

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

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

2014-05-01

363

Involvement of mitochondria and metacaspase elevation in harpin Pss-induced cell death of Saccharomyces cerevisiae.  

Science.gov (United States)

Expression of a proteinaceous elicitor harpin(Pss,) encoded by hrpZ of Pseudomonas syringae pv. syringae 61, under GAL1 promoter in Saccharomyces cerevisiae Y187 resulted in galactose-inducible yeast cell death (YCD). Extracellular treatment of harpin did not affect the growth of yeast. The observed YCD was independent of the stage of cell cycle. "Petite" mutant of S. cerevisiae Y187 pYEUT-hrpZ was insensitive to cell death indicating the involvement of mitochondria in this YCD. Loss in mitochondrial potential, but no leakage of Cytochrome c from mitochondria into the cytosol, were notable features in harpin(Pss)-induced YCD. Cyclosporin A had no effect on hrpZ expressing yeast cells, further confirmed that there was no release of Cytochrome c. Elevation of caspase activity has been reported for the first time in this form of cell death induced by harpin expression. Release of reactive oxygen species and clear loss of membrane integrity were evident with the absence of nuclear fragmentation and chromosomal condensation, while annexin V and propidium iodide staining showed features typical of necrosis. PMID:19507234

Sripriya, Paranthaman; Vedantam, Lakshmi Vasudev; Podile, Appa Rao

2009-08-15

364

Ketoacyl synthase domain is a major determinant for fatty acyl chain length in Saccharomyces cerevisiae.  

Science.gov (United States)

Yeast fatty acid synthase (Fas) comprises two subunits, ?6 and ?6, encoded by FAS2 and FAS1, respectively. To determine features of yeast Fas that control fatty acyl chain length, chimeric genes were constructed by combining FAS sequences from Saccharomyces cerevisiae (ScFAS) and Hansenula polymorpha (HpFAS), which mostly produces C16 and C18 fatty acids, respectively. The C16/C18 ratios decreased from 2.2 ± 0.1 in wild-type S. cerevisiae to 1.0 ± 0.1, 0.5 ± 0.2 and 0.8 ± 0.1 by replacement of ScFAS1, ScFAS2 and ScFAS1 ScFAS2 with HpFAS1, HpFAS2 and HpFAS1 HpFAS2, respectively, suggesting that the ?, but not ? subunits play a major role in determining fatty acyl chain length. Replacement of phosphopantetheinyl transferase (PPT) domain with the equivalent region from HpFAS2 did not affect C16/C18 ratio. Chimeric Fas2 containing half N-terminal ScFas2 and half C-terminal HpFas2 carrying H. polymorpha ketoacyl synthase (KS) and PPT gave a remarkable decrease in C16/C18 ratio (0.6 ± 0.1), indicating that KS plays a major role in determining chain length. PMID:24201996

Sangwallek, Juthaporn; Kaneko, Yoshinobu; Sugiyama, Minetaka; Ono, Hisayo; Bamba, Takeshi; Fukusaki, Eiichiro; Harashima, Satoshi

2013-12-01

365

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2010-06-15

366

Six novel genes necessary for pre-mRNA splicing in Saccharomyces cerevisiae.  

Science.gov (United States)

We have identified six new genes whose products are necessary for the splicing of nuclear pre-mRNA in the yeast Saccharomyces cerevisiae. A collection of 426 temperature-sensitive yeast strains was generated by EMS mutagenesis. These mutants were screened for pre-mRNA splicing defects by an RNA gel blot assay, using the intron- containing CRY1 and ACT1 genes as hybridization probes. We identified 20 temperature-sensitive mutants defective in pre-mRNA splicing. Twelve appear to be allelic to the previously identified prp2, prp3, prp6, prp16/prp23, prp18, prp19 or prp26 mutations that cause defects in spliceosome assembly or the first or second step of splicing. One is allelic to SNR14 encoding U4 snRNA. Six new complementation groups, prp29-prp34, were identified. Each of these mutants accumulates unspliced pre-mRNA at 37 degrees C and thus is blocked in spliceosome assembly or early steps of pre-mRNA splicing before the first cleavage and ligation reaction. The prp29 mutation is suppressed by multicopy PRP2 and displays incomplete patterns of complementation with prp2 alleles, suggesting that the PRP29 gene product may interact with that of PRP2. There are now at least 42 different gene products, including the five spliceosomal snRNAs and 37 different proteins that are necessary for pre-mRNA splicing in Saccharomyces cerevisiae. However, the number of yeast genes identifiable by this approach has not yet been exhausted. PMID:8604335

Maddock, J R; Roy, J; Woolford, J L

1996-03-15

367

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

Directory of Open Access Journals (Sweden)

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.

Wiebe Marilyn G

2009-10-01

368

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)

369

Compositions and methods for modeling Saccharomyces cerevisiae metabolism  

DEFF Research Database (Denmark)

The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S. cerevisiae reactants to a plurality of S. cerevisiae reactions, a constraint set for the plurality of S. cerevisiae reactions, and commands for determining a distribution of flux through the reactions that is predictive of a S. cerevisiae physiological function. A model of the invention can further include a gene database containing information characterizing the associated gene or genes. The invention further provides methods for making an in silica S. cerevisiae model and methods for determining a S. cerevisiae physiological function using a model of the invention. The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S. cerevisiae reactants to a plurality of S. cerevisiae reactions, a constraint set for the plurality of S. cerevisiae reactions, and commands for determining a distribution of flux through the reactions that is predictive of a S. cerevisiae physiological function. A model of the invention can further include a gene database containing information characterizing the associated gene or genes. The invention further provides methods for making an in silica S. cerevisiae model and methods for determining a S. cerevisiae physiological function using a model of the invention.

Palsson, Bernard unknown

370

Codon-optimized bacterial genes improve L-Arabinose fermentation in recombinant Saccharomyces cerevisiae.  

Science.gov (United States)

Bioethanol produced by microbial fermentations of plant biomass hydrolysates consisting of hexose and pentose mixtures is an excellent alternative to fossil transportation fuels. However, the yeast Saccharomyces cerevisiae, commonly used in bioethanol production, can utilize pentose sugars like l-arabinose or d-xylose only after heterologous expression of corresponding metabolic pathways from other organisms. Here we report the improvement of a bacterial l-arabinose utilization pathway consisting of l-arabinose isomerase from Bacillus subtilis and l-ribulokinase and l-ribulose-5-P 4-epimerase from Escherichia coli after expression of the corresponding genes in S. cerevisiae. l-Arabinose isomerase from B. subtilis turned out to be the limiting step for growth on l-arabinose as the sole carbon source. The corresponding enzyme could be effectively replaced by the enzyme from Bacillus licheniformis, leading to a considerably decreased lag phase. Subsequently, the codon usage of all the genes involved in the l-arabinose pathway was adapted to that of the highly expressed genes encoding glycolytic enzymes in S. cerevisiae. Yeast transformants expressing the codon-optimized genes showed strongly improved l-arabinose conversion rates. With this rational approach, the ethanol production rate from l-arabinose could be increased more than 2.5-fold from 0.014 g ethanol h(-1) (g dry weight)(-1) to 0.036 g ethanol h(-1) (g dry weight)(-1) and the ethanol yield could be increased from 0.24 g ethanol (g consumed l-arabinose)(-1) to 0.39 g ethanol (g consumed l-arabinose)(-1). These improvements make up a new starting point for the construction of more-efficient industrial l-arabinose-fermenting yeast strains by evolutionary engineering. PMID:18263741

Wiedemann, Beate; Boles, Eckhard

2008-04-01

371

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)

Full Text Available SciELO Colombia | Language: English Abstract in spanish 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.

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

2014-05-01

372

Role of GATA factor Nil2p in nitrogen regulation of gene expression in Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have identified the product of the NIL2 gene of Saccharomyces cerevisiae which contains a zinc finger region highly homologous to those of the GATA factors Gln3p and Nil1p as an antagonist of Nil1p and to a lesser extent of Gln3p. The expression of many nitrogen-regulated genes of Saccharomyces cerevisiae requires activation by GATA factor Gln3p or Nil1p and is prevented by the presence of glutamine in the growth medium. Disruption of NIL2 results in a great increase in the expression of N...

Rowen, D. W.; Esiobu, N.; Magasanik, B.

1997-01-01

373

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

Science.gov (United States)

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 that wine making strains have been domesticated for wine production. In this study, we demonstrate that humans can distinguish between wines produced using wine strains and wild strains of S. cerevisiae as well as its sibling species, Saccharomyces paradoxus. Wine strains produced wine with fruity and floral characteristics, whereas wild strains produced wine with earthy and sulfurous characteristics. The differences that we observe between wine and wild strains provides further evidence that wine strains have evolved phenotypes that are distinct from their wild ancestors and relevant to their use in wine production. PMID:22093681

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

2011-11-01

374

MTH1 and RGT1 demonstrate combined haploinsufficiency in regulation of the hexose transporter genes in Saccharomyces cerevisiae  

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Abstract Background The SNF3 gene in the yeast Saccharomyces cerevisiae encodes a low glucose sensor that regulates expression of an important subset of the hexose transporter (HXT) superfamily. Null mutations of snf3 result in a defect in growth on low glucose concentrations due to the inability to relieve repression of a subset of the HXT genes. The snf3 null mutation phenotype is suppressed by the loss of either one of the downs...

Dietzel Kevin L; Ramakrishnan Vidhya; Murphy Erin E; Bisson Linda F

2012-01-01

375

Balance between Transcription and RNA Degradation Is Vital for Saccharomyces cerevisiae Mitochondria: Reduced Transcription Rescues the Phenotype of Deficient RNA Degradation  

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The Saccharomyces cerevisiae SUV3 gene encodes the helicase component of the mitochondrial degradosome (mtEXO), the principal 3?-to-5? exoribonuclease of yeast mitochondria responsible for RNA turnover and surveillance. Inactivation of SUV3 (suv3?) causes multiple defects related to overaccumulation of aberrant transcripts and precursors, leading to a disruption of mitochondrial gene expression and loss of respiratory function. We isolated spontaneous suppressors that partially restore m...

Rogowska, Agata T.; Puchta, Olga; Czarnecka, Anna M.; Kaniak, Aneta; Stepien, Piotr P.; Golik, Pawel

2006-01-01

376

recA-like genes from three archaean species with putative protein products similar to Rad51 and Dmc1 proteins of the yeast Saccharomyces cerevisiae.  

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The process of homologous recombination has been documented in bacterial and eucaryotic organisms. The Escherichia coli RecA and Saccharomyces cerevisiae Rad51 proteins are the archetypal members of two related families of proteins that play a central role in this process. Using the PCR process primed by degenerate oligonucleotides designed to encode regions of the proteins showing the greatest degree of identity, we examined DNA from three organisms of a third phylogenetically divergent grou...

Sandler, S. J.; Satin, L. H.; Samra, H. S.; Clark, A. J.

1996-01-01

377

Complementation of a threonine dehydratase-deficient Nicotiana plumbaginifolia mutant after Agrobacterium tumefaciens-mediated transfer of the Saccharomyces cerevisiae ILV1 gene.  

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The Saccharomyces cerevisiae ILV1 gene, encoding threonine dehydratase (EC 4.2.1.16) was fused to the transferred DNA nopaline synthase promoter and the 3' noncoding region of the octopine synthase gene. It was introduced, by Agrobacterium tumefaciens-mediated gene transfer, into an isoleucine-requiring Nicotiana plumbaginifolia auxotroph deficient in threonine dehydratase. Functional complementation by the ILV1 gene product was demonstrated by the selection of several transformed lines on a ...

Colau, D.; Negrutiu, I.; Montagu, M.; Hernalsteens, J. P.

1987-01-01

378

A novel FK506- and rapamycin-binding protein (FPR3 gene product) in the yeast Saccharomyces cerevisiae is a proline rotamase localized to the nucleolus  

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The gene (FPR3) encoding a novel type of peptidylpropyl-cis-trans- isomerase (PPIase) was isolated during a search for previously unidentified nuclear proteins in Saccharomyces cerevisiae. PPIases are thought to act in conjunction with protein chaperones because they accelerate the rate of conformational interconversions around proline residues in polypeptides. The FPR3 gene product (Fpr3) is 413 amino acids long. The 111 COOH-terminal residues of Fpr3 share greater than 40% amino acid identi...

1994-01-01

379

Evidence that Spt2/Sin1, an HMG-Like Factor, Plays Roles in Transcription Elongation, Chromatin Structure, and Genome Stability in Saccharomyces cerevisiae  

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Spt2/Sin1 is a DNA binding protein with HMG-like domains that has been suggested to play a role in chromatin-mediated transcription in Saccharomyces cerevisiae. Previous studies have suggested models in which Spt2 plays an inhibitory role in the initiation of transcription of certain genes. In this work, we have taken several approaches to study Spt2 in greater detail. Our results have identified previously unknown genetic interactions between spt2? and mutations in genes encoding transcript...

Nourani, Amine; Robert, Francois; Winston, Fred

2006-01-01

380

Influence of cosubstrate concentration on xylose conversion by recombinant, XYL1-expressing Saccharomyces cerevisiae: a comparison of different sugars and ethanol as cosubstrates.  

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Conversion of xylose to xylitol by recombinant Saccharomyces cerevisiae expressing the XYL1 gene, encoding xylose reductase, was investigated by using different cosubstrates as generators of reduced cofactors. The effect of a pulse addition of the cosubstrate on xylose conversion in cosubstrate-limited fed-batch cultivation was studied. Glucose, mannose, and fructose, which are transported with high affinity by the same transport system as is xylose, inhibited xylose conversion by 99, 77, and...

Meinander, N. Q.; Hahn-ha?gerdal, B.

1997-01-01

 
 
 
 
381

Deletion of BCY1 from the Saccharomyces cerevisiae Genome Is Semidominant and Induces Autolytic Phenotypes Suitable for Improvement of Sparkling Wines  

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Autolysis of Saccharomyces cerevisiae is the main source of molecules that contribute to the quality of sparkling wines made by the traditional method. In this work the possibility of accelerating this slow process in order to improve the quality of sparkling wines by using genetically engineered wine yeast strains was explored. The effect of partial or total deletion of BCY1 (which encodes a regulatory subunit of cAMP-dependent protein kinase A) in haploid and diploid (heterozygous and homoz...

Tabera, Laura; Mun?oz, Rosario; Gonzalez, Ramon

2006-01-01

382

Syringomycin E Inhibition of Saccharomyces cerevisiae: Requirement for Biosynthesis of Sphingolipids with Very-Long-Chain Fatty Acids and Mannose- and Phosphoinositol-Containing Head Groups†  

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Syringomycin E is an antifungal cyclic lipodepsinonapeptide that inhibits the growth of Saccharomyces cerevisiae by interaction with the plasma membrane. A screen conducted to find the yeast genes necessary for its fungicidal action identified two novel syringomycin E response genes, SYR3 and SYR4. A syr3 mutant allele was complemented by ELO2 and ELO3. These genes encode enzymes that catalyze the elongation of sphingolipid very long chain fatty acids. Tetrad analysis showed that SYR3 was ELO...

Stock, Stephen D.; Hama, Hiroko; Radding, Jeffrey A.; Young, Debra A.; Takemoto, Jon Y.

2000-01-01

383

The Yak1 Protein Kinase Lies at the Center of a Regulatory Cascade Affecting Adhesive Growth and Stress Resistance in Saccharomyces cerevisiae  

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In Saccharomyces cerevisiae, adhesive growth on solid surfaces is mediated by the flocculin Flo11 to confer biofilm and filament formation. Expression of FLO11 is governed by a complex regulatory network that includes, e.g., the protein kinase A (PKA) signaling pathway. In addition, numerous regulatory genes, which have not been integrated into regulatory networks, affect adhesive growth, including WHI3 encoding an RNA-binding protein and YAK1 coding for a dual-specificity tyrosine-regulated ...

Malcher, Mario; Schladebeck, Sarah; Mo?sch, Hans-ulrich

2011-01-01

384

Protein Enrichment of Cassava Pulp Fermentation by Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this study was to determine intestinal digestibility of residual components of cassava pulp solid state fermentation by Saccharomyces cerevisiae for animal feed. Three ruminally cannulated animal were used to measure in situ rumen Dry Matter (DM) and Crude Protein (CP) degradability characteristics of cassava pulp solid state fermentation by S. cerevisiae. Nylon bags containing 3 g (as fed basis) of each feed was immersed in duplicate at each time point in...

Yuangklang, C.; Traiyakun, S.; Kaewwongsa, W.; Wachirapakorn, C.; Paengkoum, P.

2011-01-01

385

Galacturonic Acid Inhibits the Growth of Saccharomyces cerevisiae on Galactose, Xylose, and Arabinose  

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The efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeast Saccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation by S. cerevisiae was investigated with anaerobic batch...

Huisjes, Eline H.; Hulster, Erik; Dam, Jan C.; Pronk, Jack T.; Maris, Antonius J. A.

2012-01-01

386

Comparative transcriptome analysis between original and evolved recombinant lactose-consuming Saccharomyces cerevisiae strains  

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The engineering of Saccharomyces cerevisiae strains for lactose utilization has been attempted with the intent of developing high productivity processes for alcoholic fermentation of cheese whey. A recombinant S. cerevisiae flocculent strain that efficiently ferments lactose to ethanol was previously obtained by evolutionary engineering of an original recombinant that displayed poor lactose fermentation performance. We compared the transcriptomes of the original and the evolved re...

Guimara?es, Pedro M. R.; Le Berre, V.; Sokol, Serguei; Franc?ois, J.; Teixeira, J. A.; Domingues, Luci?lia

2008-01-01

387

Photolyases from Saccharomyces cerevisiae and Escherichia coli recognize common binding determinants in DNA containing pyrimidine dimers.  

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DNA photolyases catalyze the light-dependent repair of pyrimidine dimers in DNA. The results of nucleotide sequence analysis and spectroscopic studies demonstrated that photolyases from Saccharomyces cerevisiae and Escherichia coli share 37% amino acid sequence homology and contain identical chromophores. Do the similarities between these two enzymes extend to their interactions with DNA containing pyrimidine dimers, or does the organization of DNA into nucleosomes in S. cerevisiae necessitat...

Baer, M.; Sancar, G. B.

1989-01-01

388

Genomic Sequence Diversity and Population Structure of Saccharomyces cerevisiae Assessed by RAD-seq  

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The budding yeast Saccharomyces cerevisiae is important for human food production and as a model organism for biological research. The genetic diversity contained in the global population of yeast strains represents a valuable resource for a number of fields, including genetics, bioengineering, and studies of evolution and population structure. Here, we apply a multiplexed, reduced genome sequencing strategy (known as RAD-seq) to genotype a large collection of S. cerevisiae ...

Cromie, Gareth A.; Hyma, Katie E.; Ludlow, Catherine L.; Garmendia-torres, Cecilia; Gilbert, Teresa L.; May, Patrick; Huang, Angela A.; Dudley, Aime?e M.; Fay, Justin C.

2013-01-01

389

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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....

Tai, S. L.

2007-01-01

390

Aminoacid metabolism and the production of wine aroma compounds by Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Os produtos do metabolismo de aminoácidos por leveduras Saccharomyces cerevisiae durante a fermentação alcoólica têm um impacto relevante no perfil sensorial de vinhos. Com o objetivo de estudar a influência da composição de aminoácidos do meio na formação da base do aroma típico de vinho, meios sintéticos contendo diferentes compostos nitrogenados foram fermentados por S. cerevisiae. Em um primeiro experimento, cinco meios de composições distintas quanto à fonte de azoto fora...

Arau?jo, Leandro Dias

2012-01-01

391

Saccharomyces cerevisiae KNU5377 Stress Response during High-Temperature Ethanol Fermentation  

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Fuel ethanol production is far more costly to produce than fossil fuels. There are a number of approaches to cost-effective fuel ethanol production from biomass. We characterized stress response of thermotolerant Saccharomyces cerevisiae KNU5377 during glucose-based batch fermentation at high temperature (40°C). S. cerevisiae KNU5377 (KNU5377) transcription factors (Hsf1, Msn2/4, and Yap1), metabolic enzymes (hexokinase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydroge...

Kim, Il-sup; Kim, Young-saeng; Kim, Hyun; Jin, Ingnyol; Yoon, Ho-sung

2013-01-01

392

Isolation and characterization of the centromere from chromosome V (CEN5) of Saccharomyces cerevisiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have cloned a functional centromeric DNA sequence from Saccharomyces cerevisiae. Using the 2 mu chromosome-loss mapping technique and meiotic tetrad analysis, we have identified this DNA sequence as the centromere of chromosome V (CEN5). The CEN5 sequence has been localized on an 1,100-base-pair BamHI-BglII restriction fragment. Plasmids containing CEN5 and an autonomously replicating sequence are mitotically stable in S. cerevisiae and segregate in a Mendelian fashion during meiosis.

Maine, G. T.; Surosky, R. T.; Tye, B. K.

1984-01-01

393

Bioinformatic approaches for the genetic and phenotypic characterization of a Saccharomyces cerevisiae wine yeast collection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of the present study was to compare genetic and phenotypic variation of 103 Saccharomyces cerevisiae strains isolated from winemaking environments. We used bioinformatics approaches to identify genetically similary strains with specific phenotypes and to estimate a strain's biotechnological potential. A S. cerevisiae collection, comprising 440 strains that were obtained from winemaking environments in Portugal has been constituted during the last years. All strains were gen...

Duarte, Ricardo Franco; Umek, Lan; Zupan, Blaz; Schuller, Dorit

2008-01-01

394

The genetic and phenotypic characterization of a saccharomyces cerevisiae wine yeast collection using bioinformatic approaches  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of the present study was to compare genetic and phenotypic variation of 103 Saccharomyces cerevisiae strains isolated from winemaking environments. We used bioinformatics approaches to identify genetically similary strains with specific phenotypes and to estimate a strain's biotechnological potential. A S. cerevisiae collection, comprising 440 strains that were obtained from winemaking environments in Portugal has been constituted during the last years. All strains were genetica...

Duarte, Ricardo Franco; Umek, Lan; Zupan, Blaz; Schuller, Dorit

2008-01-01

395

Transformation of Saccharomyces cerevisiae and other fungi: Methods and possible underlying mechanism  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transformation (i.e., genetic modification of a cell by the incorporation of exogenous DNA) is indispensable for manipulating fungi. Here, we review the transformation methods for Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans, Pichia pastoris and Aspergillus species and discuss some common modifications to improve transformation efficiency. We also present a model of the mechanism underlying S. cerevisiae transformation, based on recent reports and the mechanism of tra...

Kawai, Shigeyuki; Hashimoto, Wataru; Murata, Kousaku

2010-01-01

396

The use of genetically modified Saccharomyces cerevisiae strains in the wine industry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the last decades, science and food technology have contributed at an accelerated rate to the introduction of new products to satisfy nutritional, socio-economic and quality requirements. With the emergence of modern molecular genetics, the industrial importance of Saccharomyces cerevisiae, continuously extended. The demand for suitable genetically modified (GM) S. cerevisiae strains for the biofuel, bakery and beverage industries or for the production of biotechnological products (e.g....

Schuller, Dorit; Casal, Margarida

2005-01-01

397

A Modified Saccharomyces cerevisiae Strain That Consumes l-Arabinose and Produces Ethanol  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Metabolic engineering is a powerful method to improve, redirect, or generate new metabolic reactions or whole pathways in microorganisms. Here we describe the engineering of a Saccharomyces cerevisiae strain able to utilize the pentose sugar l-arabinose for growth and to ferment it to ethanol. Expanding the substrate fermentation range of S. cerevisiae to include pentoses is important for the utilization of this yeast in economically feasible biomass-to-ethanol fermentation processes. After o...

Becker, Jessica; Boles, Eckhard

2003-01-01

398

Expression of the cloned uracil permease gene of Saccharomyces cerevisiae in a heterologous membrane.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A piece of DNA of the yeast Saccharomyces cerevisiae complementing the uracil permease gene was introduced into a plasmid able to replicate autonomously in Schizosaccharomyces pombe. A strain of S. pombe lacking uracil transport activity was transformed with this new plasmid carrying the gene of S. cerevisiae. The behaviour of the transformant shows not only an expression of the uracil permease gene in the heterologous membrane but also that the transport of uracil is active and coupled to th...

Chevallier, M. R.; Lacroute, F.

1982-01-01

399

L-Carnosine Affects the Growth of Saccharomyces cerevisiae in a Metabolism-Dependent Manner  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The dipeptide L-carnosine (?-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabol...

Cartwright, Stephanie P.; Bill, Roslyn M.; Hipkiss, Alan R.

2012-01-01

400

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Rey, Simon Scheel

2011-01-01

 
 
 
 
401

Affinity of glucose transport in Saccharomyces cerevisiae is modulated during growth on glucose.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

By using a modified technique to measure glucose uptake in Saccharomyces cerevisiae, potential uncertainties have been identified in previous determinations. These previous determinations had led to the proposal that S. cerevisiae contained a constitutive low-affinity glucose transporter and a glucose-repressible high-affinity transporter. We show that, upon transition from glucose-repressed to -derepressed conditions, the maximum rate of glucose transport is constant and only the affinity fo...

Walsh, M. C.; Smits, H. P.; Scholte, M. E.; Dam, K.

1994-01-01

402

Directed Evolution of Xylose Isomerase for Improved Xylose Catabolism and Fermentation in the Yeast Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The heterologous expression of a highly functional xylose isomerase pathway in Saccharomyces cerevisiae would have significant advantages for ethanol yield, since the pathway bypasses cofactor requirements found in the traditionally used oxidoreductase pathways. However, nearly all reported xylose isomerase-based pathways in S. cerevisiae suffer from poor ethanol productivity, low xylose consumption rates, and poor cell growth compared with an oxidoreductase pathway and, additionally, often r...

Lee, Sun-mi; Jellison, Taylor; Alper, Hal S.

2012-01-01

403

Integrated analysis of regulatory and metabolic networks reveals novel regulatory mechanisms in Saccharomyces cerevisiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe the use of model-driven analysis of multiple data types relevant to transcriptional regulation of metabolism to discover novel regulatory mechanisms in Saccharomyces cerevisiae. We have reconstructed the nutrient-controlled transcriptional regulatory network controlling metabolism in S. cerevisiae consisting of 55 transcription factors regulating 750 metabolic genes, based on information in the primary literature. This reconstructed regulatory network coupled with an existing geno...

Herrga?rd, Markus J.; Lee, Baek-seok; Portnoy, Vasiliy; Palsson, Bernhard Ø.

2006-01-01

404

Hxt-Carrier-Mediated Glucose Efflux upon Exposure of Saccharomyces cerevisiae to Excess Maltose  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When wild-type Saccharomyces cerevisiae strains pregrown in maltose-limited chemostat cultures were exposed to excess maltose, release of glucose into the external medium was observed. Control experiments confirmed that glucose release was not caused by cell lysis or extracellular maltose hydrolysis. To test the hypothesis that glucose efflux involved plasma membrane glucose transporters, experiments were performed with an S. cerevisiae strain in which all members of the hexose transporter (H...

Jansen, M. L. A.; Winde, J. H.; Pronk, J. T.

2002-01-01

405

Overexpression of Mal61p in Saccharomyces cerevisiae and characterization of maltose transport in artificial membranes.  

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For maltose uptake in Saccharomyces cerevisiae, multiple kinetic forms of transport as well as inhibition of transport by high concentrations of maltose at the trans side of the plasma membrane have been described. Most of these studies were hampered by a lack of genetically well-defined mutants and/or the lack of an artificial membrane system to study translocation catalysis in vitro. A genetically well-defined S. cerevisiae strain lacking the various MAL loci was constructed by gene disrupt...

Rest, M. E.; Vries, Y.; Poolman, B.; Konings, W. N.

1995-01-01

406

Studies of anaerobic and aerobic glycolysis in Saccharomyces cerevisiae  

International Nuclear Information System (INIS)

Glucose metabolism was followed in suspensions of Saccharomyces cerevisiae by using 13C NMR and 14C radioactive labeling techniques and by Warburg manometer experiments. These experiments were performed for cells grown with various carbon sources in the growth medium, so as to evaluate the effect of catabolite repression. The rate of glucose utilization was most conveniently determined by the 13C NMR experiments, which measured the concentration of [1-13C]glucose, whereas the distribution of end products was determined from the 13C and the 14C experiments. By combining these measurements the flows into the various pathways that contribute to glucose catabolism were estimated, and the effect of oxygen upon glucose catabolism was evaluated. From these measurements, the Pasteur quotient (PQ) for glucose catabolism was calculated to be 2.95 for acetate-grown cells and 1.89 for cells grown on glucose into saturation. The Warburg experiments provided an independent estimate of glucose catabolism. The PQ estimated from Warburg experiments was 2.9 for acetate-grown cells in excellent agreement with the labeled carbon experiments and 4.6 for cells grown into saturation, which did not agree. Possible explanations of these differences are discussed. From these data an estimate is obtained of the net flow through the Embden-Meyerhof-Parnas pathway. The backward flow through fructose-1,6-bisphosphatase (Fru-1,6-P2-ase) was calculated from the scrambling of the 13C label of [1-13C]the scrambling of the 13C label of [1-13C]glucose into the C1 and C6 positions of trehalose. Combining these data allowed us to calculate the net flux through phosphofructokinase (PFK). For acetate-grown cells we found that the relative flow through PFK is a factor of 1.7 faster anaerobically than aerobically

407

Expression of heteropolymeric ferritin improves iron storage in Saccharomyces cerevisiae.  

Science.gov (United States)

Saccharomyces cerevisiae was engineered to express different amount of heavy (H)- and light (L)-chain subunits of human ferritin by using a low-copy integrative vector (YIp) and a high-copy episomal vector (YEp). In addition to pep4::HIS3 allele, the expression host strain was bred to have the selection markers leu2(-) and ura3(-) for YIplac128 and YEp352, respectively. The heterologous expression of phytase was used to determine the expression capability of the host strain. Expression in the new host strain (2805-a7) was as high as that in the parental strain (2805), which expresses high levels of several foreign genes. Following transformation, Northern and Western blot analyses demonstrated the expression of H- and L-chain genes. The recombinant yeast was more iron tolerant, in that transformed cells formed colonies on plates containing more than 25 mM ferric citrate, whereas none of the recipient strain cells did. Prussian blue staining indicated that the expressed isoferritins were assembled in vivo into a complex that bound iron. The expressed subunits showed a clear preference for the formation of heteropolymers over homopolymers. The molar ratio of H to L chains was estimated to be 1:6.8. The gel-purified heteropolymer took up iron faster than the L homopolymer, and it took up more iron than the H homopolymer did. The iron concentrations in transformants expressing the heteropolymer, L homopolymer, and H homopolymer were 1,004, 760, and 500 micro g per g (dry weight) of recombinant yeast cells, respectively. The results indicate that heterologously expressed H and L subunits coassemble into a heteropolymer in vivo and that the iron-carrying capacity of yeast is further enhanced by the expression of heteropolymeric isoferritin. PMID:12676675

Kim, Hye-Jin; Kim, Hyang-Mi; Kim, Ji-Hye; Ryu, Kyeong-Seon; Park, Seung-Moon; Jahng, Kwang-Yeup; Yang, Moon-Sik; Kim, Dae-Hyuk

2003-04-01

408

Metabolic engineering of muconic acid production in Saccharomyces cerevisiae.  

Science.gov (United States)

The dicarboxylic acid muconic acid has garnered significant interest due to its potential use as a platform chemical for the production of several valuable consumer bio-plastics including nylon-6,6 and polyurethane (via an adipic acid intermediate) and polyethylene terephthalate (PET) (via a terephthalic acid intermediate). Many process advantages (including lower pH levels) support the production of this molecule in yeast. Here, we present the first heterologous production of muconic acid in the yeast Saccharomyces cerevisiae. A three-step synthetic, composite pathway comprised of the enzymes dehydroshikimate dehydratase from Podospora anserina, protocatechuic acid decarboxylase from Enterobacter cloacae, and catechol 1,2-dioxygenase from Candida albicans was imported into yeast. Further genetic modifications guided by metabolic modeling and feedback inhibition mitigation were introduced to increase precursor availability. Specifically, the knockout of ARO3 and overexpression of a feedback-resistant mutant of aro4 reduced feedback inhibition in the shikimate pathway, and the zwf1 deletion and over-expression of TKL1 increased flux of necessary precursors into the pathway. Further balancing of the heterologous enzyme levels led to a final titer of nearly 141mg/L muconic acid in a shake-flask culture, a value nearly 24-fold higher than the initial strain. Moreover, this strain has the highest titer and second highest yield of any reported shikimate and aromatic amino acid-based molecule in yeast in a simple batch condition. This work collectively demonstrates that yeast has the potential to be a platform for the bioproduction of muconic acid and suggests an area that is ripe for future metabolic engineering efforts. PMID:23164574

Curran, Kathleen A; Leavitt, John M; Karim, Ashty S; Alper, Hal S

2013-01-01

409

Metabolic engineering of Saccharomyces cerevisiae for optimizing 3HP production  

DEFF Research Database (Denmark)

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.

Jensen, Niels Bjerg; Maury, Jerome

2012-01-01

410

Genetic basis of arsenite and cadmium tolerance in Saccharomyces cerevisiae  

Directory of Open Access Journals (Sweden)

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.

Dawes Ian W

2009-03-01

411

Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium  

DEFF Research Database (Denmark)

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.

Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth

2014-01-01

412

IMMOBILIZATION OF Saccharomyces cerevisiae IN RICE HULLS FOR ETHANOL PRODUCTION  

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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.

Don-Hee Park

2010-11-01

413

Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae.  

Science.gov (United States)

Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (-)-limonene synthase from Perilla frutescens and a (+)-limonene synthase from Citrus limon. Both proteins were expressed either with their native plastid targeting signal or in a truncated form in which the plastidial sorting signal was removed. The yeast host strain for expression was AE9 K197G, which expresses a mutant Erg20 enzyme. This enzyme catalyses the formation of geranyl diphosphate, which is the precursor for monoterpenes. Several methods were tested to capture limonene produced by the yeast. Extraction from the culture medium by pentane, or by the addition of CaCl2 followed by solid-phase micro-extraction, did not lead to detectable limonene, indicating that limonene is rapidly lost from the culture medium. Volatile terpenes such as limonene may also be trapped in a dodecane phase added to the medium during fermentation. This method resulted in recovery of 0.028?mg/l (+)-limonene and 0.060?mg/l (-)-limonene in strains using the truncated Citrus and Perilla synthases, respectively. Trapping the headspace during culture of the limonene synthase-expressing strains resulted in higher titres, at 0.12?mg/l (+)-limonene and 0.49?mg/l (-)-limonene. These results show that the volatile properties of the olefins produced require specific methods for efficient recovery of these molecules from biotechnological production systems. Gene Bank Nos were: KM015220 (Perilla limonene synthase; this study); AF317695 (Perilla limonene synthase; Yuba et al., ); AF514287.1 (Citrus limonene synthase; Lucker et al., ). Copyright © 2014 John Wiley & Sons, Ltd. PMID:25164098

Jongedijk, Esmer; Cankar, Katarina; Ranzijn, Jorn; van der Krol, Sander; Bouwmeester, Harro; Beekwilder, Jules

2015-01-01

414

Ethanol production from carob extract by using Saccharomyces cerevisiae.  

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Carob has been widely grown in the Mediterranean region for a long time. It has been regarded as only a forest tree and has been neglected for other economical benefits. However, in recent years, this fruit has gained attention for several applications. As petroleum has become depleted, renewable energy production has started to gain attention all over the world; including the production of ethanol from underutilized agricultural products such as carob. In this project, the optimum extraction conditions were determined for the carob fruit by using the response surface design method. The obtained extract was utilized for production of ethanol by using suspended Saccharomyces cerevisiae fermentation. The effect of various fermentation parameters such as pH, media content and inoculum size were evaluated for ethanol fermentation in carob extract. Also, in order to determine economically appropriate nitrogen sources, four different nitrogen sources were evaluated. The optimum extraction condition for carob extract was determined to be 80 degrees C, 2h in 1:4 dilution rate (fruit: water ratio) according to the result of response surface analysis (115.3g/L). When the fermentation with pH at 5.5 was applied, the final ethanol concentration and production rates were 42.6g/L and 3.37 g/L/h, respectively, which were higher than using an uncontrolled pH. Among inoculum sizes of 1%, 3%, and 5%, 3% was determined as the best inoculum size. The maximum production rate and final ethanol concentration were 3.48 g/L/h and 44.51%, respectively, with an alternative nitrogen source of meat-bone meal. Overall, this study suggested that carob extract can be utilized for production of ethanol in order to meet the demands of renewable energy. PMID:20189805

Turhan, Irfan; Bialka, Katherine L; Demirci, Ali; Karhan, Mustafa

2010-07-01

415

In vivo rearrangement of mitochondrial DNA in Saccharomyces cerevisiae.  

Science.gov (United States)

A revertant (SPR1) from a high-frequency petite strain of Saccharomyces cerevisiae has been shown by mapping and sequence analysis to have a rearranged mitochondrial genome. In vivo rearrangement has occurred through a subgenomic-recombination pathway involving the initial formation of subgenomic molecules in nascent petite mutants, recombination between these molecules to form an intermediate with direct repeats, and subsequent excision of the resident or symposed duplication to yield a molecule with three novel junctions and a changed gene order. Sequencing of the novel junctions shows that intramolecular recombination in each case occurs by means of G + C-rich short direct repeats of 40-51 base pairs. Mapping and sequence analysis also reveal that the SPR1 mitochondrial genome lacks three sectors of the wild-type molecule of 4.4, 1.7, and 0.5 kilobases. Each of these sectors occurs in nontemplate, base-biased DNA, that is over 90% A + T. Absence of these sectors together with a rearranged gene order does not appear to affect the phenotype of SPR1, as colony morphology and growth rate on a number of different substrates are not detectably different from the wild type. Lack of phenotypic change suggests that mitochondrial gene expression has not been noticeably disrupted in SPR1 despite deletion of the consensus nonomer promoter upstream from the glutamic acid tRNA gene. Dispensability of DNA sectors and the presence of recombinogenic short, direct repeats are mandatory features of the subgenomic-recombination pathway for creating rearrangements in baker's yeast mtDNA. It is proposed that, in other organisms, organelle genomes containing these elements may undergo rearrangement by the same steps. Images PMID:2682661

Clark-Walker, G D

1989-01-01

416

Process oscillations in continuous ethanol fermentation with Saccharomyces cerevisiae  

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A system composed of a continuously stirred tank reactor (CSTR) and 3 tubular bioreactors was developed for continuous very high gravity (VHG) ethanol fermentation with Saccharomyces cerevisiae. When a VHG medium containing 280 g 1-1 glucose was fed into the CSTR at a dilution rate of 0.027 per hour, sustainable oscillations of residual glucose, ethanol, and biomass were observed. The oscillations were due to ethanol inhibition and the lag response of yeast cells to ethanol inhibition. In order to study the impact of residual glucose and ethanol concentrations on the oscillations, a high gravity (HG) medium containing 200 g 1-1 glucose and a low gravity (LG) medium containing 120 g 1-1 glucose were fed into the CSTR at the same dilution rate as that for the VHG medium. The oscillations were not highly affected when the HG medium was used. Although residual glucose decreased considerably, ethanol remained at the same level, indicating that residual glucose was not the main factor affecting the oscillations. The experimental results confirmed that ethanol can trigger oscillations once its concentration approaches a criterion. The impact of dilution rate on oscillations was also studied. It was found that oscillations occurred at certain dilution rate ranges for two yeast strains. The impact of yeast cell immobilization was studied using several different packing materials. Ethanol fermentation improved and oscillation was attenuated when wood chips were used with Intalox ceramic saddles, but not when porous polyurethane particles were used with steel Raschig rings. Good results were obtained in a dynamic simulation using a newly developed dynamic model which incorporated the lag response of yeast cells to ethanol inhibition into a pseudo-steady state kinetic model.

Bai, F.

2008-07-01

417

Messenger RNA guanlyltransferase from Saccharomyces cerevisiae. II. Catalytic properties.  

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Highly purified mRNA-capping enzyme from Saccharomyces cerevisiae catalyzes (a) removal of the gamma-phosphoryl group from the 5'-end of the newly formed mRNA and (b) guanylylation of the resulting diphosphoryl end. Characteristics of the two reactions catalyzed by this enzyme are studied. Guanylyltransferase is most active at pH 7.0 in the presence of 3 mM Mg2+, and utilizes GTP as a guanylyl donor with an apparent Km of 5 microM, and ppGCC (A2, U2, G)n as a guanylyl acceptor with two Km values of 0.5 and 4 microM. It catalyzes GTP-PPi exchange in the absence of the acceptor RNA, and forms a covalent enzyme-GMP intermediate having Mr = 45,000 in sodium dodecyl sulfate gel electrophoresis. RNAs with 5'-diphosphoryl as well as 5'-triphosphoryl ends are capped, while mononucleotides such as GDP and ppGp are inert. Since guanylyltransferase can utilize ppGpC and ppGpCpC as acceptors, the presence of at least one phosphodiester bond seems to be sufficient for the acceptor activity. However, oligonucleotides of longer chain length are preferred. RNA 5'-triphosphatase associated with the purified enzyme requires Mg2+ and exhibits a broad pH optimum from 6.5 to 8.5, and an apparent Km value for pppA-terminated poly(A) is 1.4 microM. The enzyme is specific for the gamma-phosphoryl group at the 5'-terminus of RNA and does not hydrolyze ATP. It can hydrolyze the gamma-phosphoryl group of pppGp, but the RNA substrates with longer chain length are preferred. PMID:6094533

Itoh, N; Mizumoto, K; Kaziro, Y

1984-11-25

418

Predicting functional upstream open reading frames in Saccharomyces cerevisiae  

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Full Text Available Abstract Background Some upstream open reading frames (uORFs regulate gene expression (i.e., they are functional and can play key roles in keeping organisms healthy. However, how uORFs are involved in gene regulation is not yet fully understood. In order to get a complete view of how uORFs are involved in gene regulation, it is expected that a large number of experimentally verified functional uORFs are needed. Unfortunately, wet-experiments to verify that uORFs are functional are expensive. Results In this paper, a new computational approach to predicting functional uORFs in the yeast Saccharomyces cerevisiae is presented. Our approach is based on inductive logic programming and makes use of a novel combination of knowledge about biological conservation, Gene Ontology annotations and genes' responses to different conditions. Our method results in a set of simple and informative hypotheses with an estimated sensitivity of 76%. The hypotheses predict 301 further genes to have 398 novel functional uORFs. Three (RPC11, TPK1, and FOL1 of these 301 genes have been hypothesised, following wet-experiments, by a related study to have functional uORFs. A comparison with another related study suggests that eleven of the predicted functional uORFs from genes LDB17, HEM3, CIN8, BCK2, PMC1, FAS1, APP1, ACC1, CKA2, SUR1, and ATH1 are strong candidates for wet-lab experimental studies. Conclusions Learning based prediction of functional uORFs can be done with a high sensitivity. The predictions made in this study can serve as a list of candidates for subsequent wet-lab verification and might help to elucidate the regulatory roles of uORFs.

Kristiansson Erik

2009-12-01

419

Heterologous expression of glycerol 3-phosphate dehydrogenase gene [DhGPD1] from the osmotolerant yeast Debaryomyces hansenii in Saccharomyces cerevisiae.  

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The role for the gene encoding glycerol 3-phosphate dehydrogenase (DhGPD1) from the osmotolerant yeast Debaryomyces hansenii, in glycerol production and halotolerance, was studied through its heterologous expression in a Saccharomyces cerevisiae strain deficient in glycerol synthesis (gpd1Delta). The expression of the DhGPD1 gene in the gpd1Delta background restored glycerol production and halotolerance to wild type levels, corroborating its role in the salt-induced production of glycerol. Although the gene was functional in S. cerevisiae, its heterologous expression was not efficient, suggesting that the regulatory mechanism may not be shared by these two yeasts. PMID:16049663

Thomé, Patricia E

2005-08-01

420

Cloning of the STE5 gene of Saccharomyces cerevisiae as a suppressor of the mating defect of cdc25 temperature-sensitive mutants.  

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The STE5 gene of Saccharomyces cerevisiae was cloned using a screening procedure designed to isolate genes of the S. cerevisiae pheromone response pathway. We screened a yeast genomic high-copy-number plasmid library for genes that allow mating of cdc25ts mutants at the restrictive temperature without affecting the cell-cycle-arrest phenotype. One of the genes cloned was identified by genetic analysis as STE5. STE5 encodes a predicted open reading frame of 916 amino acids and exhibits signifi...

Perlman, R.; Yablonski, D.; Simchen, G.; Levitzki, A.

1993-01-01

 
 
 
 
421

Dicistronic regulation of fluorescent proteins in the budding yeast Saccharomyces cerevisiae.  

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Fluorescent proteins are convenient tools for measuring protein expression levels in the budding yeast Saccharomyces cerevisiae. Co-expression of proteins from distinct vectors has been seen by fluorescence microscopy; however, the expression of two fluorescent proteins on the same vector would allow for monitoring of linked events. We engineered constructs to allow dicistronic expression of red and green fluorescent proteins and found that expression levels of the proteins correlated with their order in the DNA sequence, with the protein encoded by the 5'-gene more highly expressed. To increase expression levels of the second gene, we tested four regulatory elements inserted between the two genes: the IRES sequences for the YAP1 and p150 genes, and the promoters for the TEF1 gene from both S. cerevisiae and Ashbya gossypii. We generated constructs encoding the truncated ADH1 promoter driving expression of the red protein, yeast-enhanced Cherry, followed by a regulatory element driving expression of the green protein, yeast-enhanced GFP. Three of the four regulatory elements successfully enhanced expression of the second gene in our dicistronic construct. We have developed a method to express two genes simultaneously from one vector. Both genes are codon-optimized to produce high protein levels in yeast, and the protein products can be visualized by microscopy or flow cytometry. With this method of regulation, the two genes can be driven in a dicistronic manner, with one protein marking cells harbouring the vector and the other protein free to mark any event of interest. PMID:20017217

Edwards, Sarah R; Wandless, Thomas J

2010-04-01

422

Isolation and characterization of a mutant recombinant Saccharomyces cerevisiae strain with high efficiency xylose utilization.  

Science.gov (United States)

A recombinant xylose-utilizing Saccharomyces cerevisiae strain carrying one copy of heterologous XYL1 and XYL2 from Pichia stipitis and endogenous XKS1 under the control of the TDH3 promoter in the chromosomal DNA was constructed from the industrial haploid yeast strain NAM34-4C, which showed thermotolerance and acid tolerance. The recombinant S. cerevisiae strain SCB7 grew in minimal medium containing xylose as the sole carbon source, and its shortest generation time (G(short)) was 5 h. From this strain, four mutants showing rapid growth (G(short) = 2.5 h) in the minimal medium were isolated. The mutants carried four mutations that were classified into three linkage groups. Three mutations were dominant and one mutation was recessive to the wild type allele. The recessive mutation was in the PHO13 gene encoding para-nitrophenyl phosphatase. The other mutant genes were not linked to TAL1 gene encoding transaldolase. When the mutants and their parental strain were used for the batch fermentation in a complex medium at pH 4.0 containing 30 g/L xylose at 35 °C with shaking (60 rpm) and an initial cell density (Absorbance at 660 nm) of 1.0, all mutants showed efficient ethanol production and xylose consumption from the early stage of the fermentation culture. In two mutants, within 24 h, 4.8 g/L ethanol was produced, and the ethanol yield was 47%, which was 1.4 times higher than that achieved with the parental strain. The xylose concentration in the medium containing the mutant decreased linearly at a rate of 1 g/L/h until 24 h. PMID:23810666

Tomitaka, Masataka; Taguchi, Hisataka; Fukuda, Kohsai; Akamatsu, Takashi; Kida, Kenji

2013-12-01

423

Malic acid production by Saccharomyces cerevisiae: engineering of pyruvate carboxylation, oxaloacetate reduction, and malate export.  

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Malic acid is a potential biomass-derivable "building block" for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate. This redox- and ATP-neutral, CO(2)-fixing pathway has a theoretical maximum yield of 2 mol malate (mol glucose)(-1). A previously engineered glucose-tolerant, C(2)-independent pyruvate decarboxylase-negative S. cerevisiae strain was used as the platform to evaluate the impact of individual and combined introduction of three genetic modifications: (i) overexpression of the native pyruvate carboxylase encoded by PYC2, (ii) high-level expression of an allele of the MDH3 gene, of which the encoded malate dehydrogenase was retargeted to the cytosol by deletion of the C-terminal peroxisomal targeting sequence, and (iii) functional expression of the Schizosaccharomyces pombe malate transporter gene SpMAE1. While single or double modifications improved malate production, the highest malate yields and titers were obtained with the simultaneous introduction of all three modifications. In glucose-grown batch cultures, the resulting engineered strain produced malate at titers of up to 59 g liter(-1) at a malate yield of 0.42 mol (mol glucose)(-1). Metabolic flux analysis showed that metabolite labeling patterns observed upon nuclear magnetic resonance analyses of cultures grown on (13)C-labeled glucose were consistent with the envisaged nonoxidative, fermentative pathway for malate production. The engineered strains still produced substantial amounts of pyruvate, indicating that the pathway efficiency can be further improved. PMID:18344340

Zelle, Rintze M; de Hulster, Erik; van Winden, Wouter A; de Waard, Pieter; Dijkema, Cor; Winkler, Aaron A; Geertman, Jan-Maarten A; van Dijken, Johannes P; Pronk, Jack T; van Maris, Antonius J A

2008-05-01

424

Construction of lactose-consuming Saccharomyces cerevisiae for lactose fermentation into ethanol fuel.  

Science.gov (United States)

Two lactose-consuming diploid Saccharomyces cerevisiae strains, AY-51024A and AY-51024M, were constructed by expressing the LAC4 and LAC12 genes of Kluyveromyces marxianus in the host strain AY-5. In AY-51024A, both genes were targeted to the ATH1 and NTH1 gene-encoding regions to abolish the activity of acid/neutral trehalase. In AY-51024M, both genes were respectively integrated into the MIG1 and NTH1 gene-encoding regions to relieve glucose repression. Physiologic studies of the two transformants under anaerobic cultivations in glucose and galactose media indicated that the expression of both LAC genes did not physiologically burden the cells, except for AY-51024A in glucose medium. Galactose consumption was initiated at higher glucose concentrations in the MIG1 deletion strain AY-51024M than in the corresponding wild-type strain and AY-51024A, wherein galactose was consumed until glucose was completely depleted in the mixture. In lactose medium, the Sp. growth rates of AY-51024A and AY-51024M under anaerobic shake-flasks were 0.025 and 0.067 h(-1), respectively. The specific lactose uptake rate and ethanol production of AY-51024M were 2.50 g lactose g CDW(-1) h(-1) and 23.4 g l(-1), respectively, whereas those of AY-51024A were 0.98 g lactose g CDW(-1) h(-1) and 24.3 g lactose g CDW(-1) h(-1), respectively. In concentrated cheese whey powder solutions, AY-51024M produced 63.3 g l(-1) ethanol from approximately 150 g l(-1) initial lactose in 120 h, conversely, AY-51024A consumed 63.7 % of the initial lactose and produced 35.9 g l(-1) ethanol. Therefore, relieving glucose repression is an effective strategy for constructing lactose-consuming S. cerevisiae. PMID:23344501

Zou, Jing; Guo, Xuewu; Shen, Tong; Dong, Jian; Zhang, Cuiying; Xiao, Dongguang

2013-04-01

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