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1

Peroxisome biogenesis in Saccharomyces cerevisiae  

Microsoft Academic Search

The observation that peroxisomes ofSaccharomyces cerevisiae can be induced by oleic acid has opened the possibility to investigate the biogenesis of these organelles in a biochemically and genetically well characterized organism. Only few enzymes have been identified as peroxisomal proteins inSaccharomyces cerevisiae so far; the three enzymes involved in ß-oxidation of fatty acids, enzymes of the glyoxylate cycle, catalase A

Wolf-H. Kunau; Andreas Hartig

1992-01-01

2

Xylose fermentation by Saccharomyces cerevisiae  

Microsoft Academic Search

We have performed a comparative study of xylose utilization in Saccharomyces cerevisiae transformants expressing two key enzymes in xylose metabolism, xylose reductase (XR) and xylitol dehydrogenase (XDH), and in a prototypic xylose-utilizing yeast, Pichia stipitis. In the absence of respiration (see text), baker's yeast cells convert half of the xylose to xylitol and ethanol, whereas P. stipilis cells display rather

Peter Kötter; Michael Ciriacy

1993-01-01

3

The proteome of Saccharomyces cerevisiae mitochondria  

E-print Network

The proteome of Saccharomyces cerevisiae mitochondria Albert Sickmann*, Jo¨ rg Reinders*, Yvonne of Saccharomyces cerevisiae mitochondria. The proteins of highly pure yeast mitochondria were separated by several were identified, indicating an involvement of mitochondria in numerous cellular processes. All known

Economou, Tassos

4

Lactose fermentation by recombinant Saccharomyces cerevisiae strains  

Microsoft Academic Search

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

Pedro M. R. Guimarães; José A. Teixeira; Lucília Domingues

5

Fatal Saccharomyces Cerevisiae Aortic Graft Infection  

NASA Technical Reports Server (NTRS)

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

6

Sterol methylation in Saccharomyces cerevisiae.  

PubMed Central

Various nystatin-resistant mutants defective in S-adenosylmethionine: delta 24-sterol-C-methyltransferase (EC 2.1.1.41) were shown to possess alleles of the same gene, erg6. The genetic map location of erg6 was shown to be close to trp1 on chromosome 4. Despite the single locus for erg6, S-adenosylmethionine: delta 24-sterol-C-methyltransferase enzyme activity was found in three separate fractions: mitochondria, microsomes, and the "floating lipid layer." The amount of activity in each fraction could be manipulated by assay conditions. The lipids and lipid synthesis of mutants of Saccharomyces cerevisiae defective in the delta 24-sterol-C-methyltransferase were compared with a C5(6) desaturase mutant and parental wild types. No ergosterol (C28 sterol) could be detected in whole-cell sterol extracts of the erg6 mutants, the limits of detection being less than 10(-11) mol of ergosterol per 10(8) cells. The distribution of accumulated sterols by these mutants varied with growth phase and between free and esterified fractions. The steryl ester concentrations of the mutants were eight times higher than those of the wild type from exponential growth samples. However, the concentration of the ester accumulated by the mutants was not as great in stationary-phase cells. Whereas the head group phospholipid composition was the same between parental and mutant strains, strain-dependent changes in fatty acids were observed, most notably a 40% increase in the oleic acid content of phosphatidylethanolamine of one erg6 mutant, JR5. PMID:6363386

McCammon, M T; Hartmann, M A; Bottema, C D; Parks, L W

1984-01-01

7

Fidelity of conjugation in Saccharomyces cerevisiae  

Microsoft Academic Search

An efficient method for the production of synchronous zygotes in Saccharomyces cerevisiae is described. Cells were synchronised under defined conditions in either an a, a mixed culture or by incubation of each mating type in cell-free medium in which cells of the opposite mating type had been grown. Synchronised cells were allowed to fuse under defined conditions on filter membranes.

David Rogers; Howard Bussey

1978-01-01

8

Transcriptional Regulatory Networks in Saccharomyces cerevisiae  

Microsoft Academic Search

One of the main goals of systems biology is reverse engineering network structures from experimental data. Using quantitative networks measures, biological processes can be characterized and understood on a systems level. This paper reviews the scien- tific literature on the transcriptional regulatory networks of Saccharomyces cerevisiae to discuss what kind of structures can be identified and what this means biologically.

Laurens Kraal

9

Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions  

ERIC Educational Resources Information Center

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

10

Transcriptional Regulatory Networks in Saccharomyces cerevisiae  

Microsoft Academic Search

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

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

2002-01-01

11

Asymmetrical division of Saccharomyces cerevisiae.  

PubMed Central

The unequal division model proposed for budding yeast (L. H. Hartwell and M. W. Unger, J. Cell Biol. 75:422-435, 1977) was tested by bud scar analyses of steady-state exponential batch cultures of Saccharomyces cerevisiae growing at 30 degrees C at 19 different rates, which were obtained by altering the carbon source. The analyses involved counting the number of bud scars, determining the presence or absence of buds on at least 1,000 cells, and independently measuring the doubling times (gamma) by cell number increase. A number of assumptions in the model were tested and found to be in good agreement with the model. Maximum likelihood estimates of daughter cycle time (D), parent cycle time (P), and the budded phase (B) were obtained, and we concluded that asymmetrical division occurred at all growth rates tested (gamma, 75 to 250 min). D, P, and B are all linearly related to gamma, and D, P, and gamma converge to equality (symmetrical division) at gamma = 65 min. Expressions for the genealogical age distribution for asymmetrically dividing yeast cells were derived. The fraction of daughter cells in steady-state populations is e-alpha P, and the fraction of parent cells of age n (where n is the number of buds that a cell has produced) is (e-alpha P)n-1(1-e-alpha P)2, where alpha = IN2/gamma; thus, the distribution changes with growth rate. The frequency of cells with different numbers of bud scars (i.e., different genealogical ages) was determined for all growth rates, and the observed distribution changed with the growth rate in the manner predicted. In this haploid strain new buds formed adjacent to the previous buds in a regular pattern, but at slower growth rates the pattern was more irregular. The median volume of the cells and the volume at start in the cell cycle both increased at faster growth rates. The implications of these findings for the control of the cell cycle are discussed. PMID:6991494

Lord, P G; Wheals, A E

1980-01-01

12

Mechanism of Uranium mineralization by Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

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

13

Replicative and Chronological Aging in Saccharomyces cerevisiae  

PubMed Central

Saccharomyces cerevisiae has directly or indirectly contributed to the identification of arguably more mammalian genes that affect aging than any other model organism. Aging in yeast is assayed primarily by measuring replicative or chronological lifespan. Here, we review the genes and mechanisms implicated in these two aging model systems and key remaining issues that need to be addressed to optimize these assays. Because of its well-characterized genome and proteome that is remarkably amenable to genetic manipulation and high-throughput screening procedures, S. cerevisiae will continue to serve as a leading model organism to study pathways relevant to human aging and disease. PMID:22768836

Longo, Valter D.; Shadel, Gerald S.; Kaeberlein, Matt; Kennedy, Brian

2012-01-01

14

Mechanisms of ethanol tolerance in Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae is a superb ethanol producer, yet is also sensitive to higher ethanol concentrations especially under high gravity or very\\u000a high gravity fermentation conditions. Ethanol tolerance is associated with interplay of complex networks at the genome level.\\u000a Although significant efforts have been made to study ethanol stress response in past decades, mechanisms of ethanol tolerance\\u000a are not well known.

Menggen Ma; Z. Lewis Liu

2010-01-01

15

Progress in Metabolic Engineering of Saccharomyces cerevisiae  

PubMed Central

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 engineering, evolutionary engineering, and global transcription machinery engineering, in yeast strain improvement. It also summarizes existing tools for fine-tuning and regulating enzyme activities and thus metabolic pathways. Recent examples of yeast metabolic engineering for food, beverage, and industrial biotechnology (bioethanol and bulk and fine chemicals) follow. S. cerevisiae currently enjoys increasing popularity as a production organism in industrial (“white”) biotechnology due to its inherent tolerance of low pH values and high ethanol and inhibitor concentrations and its ability to grow anaerobically. Attention is paid to utilizing lignocellulosic biomass as a potential substrate. PMID:18772282

Nevoigt, Elke

2008-01-01

16

Communications to the Editor Cadmium Biosorption by Saccharomyces cerevisiae  

E-print Network

Communications to the Editor Cadmium Biosorption by Saccharomyces cerevisiae 6. Volesky,* H. May June 9, 1992/Accepted November 12, 1992 Cadmium uptake by nonliving and resting cells of Saccharomyces cerevisiae obtained from aerobic or anaerobic cultures from pure cadmium-bearing solu- tions was examined

Volesky, Bohumil

17

Assembly of F0 in Saccharomyces cerevisiae  

PubMed Central

Respiratory deficient mutants of Saccharomyces cerevisiae have been instrumental in identifying an increasing number of nuclear gene products that promote pre- and post-translational steps of the pathway responsible for biogenesis of the mitochondrial ATP synthase. In this article we have attempted to marshal current information about the functions of such accessory factors and the roles they play in expression and assembly of the mitochondrially encoded subunits of the ATP synthase. We also discuss evidence that the ATP synthase may be build up from three separate modules corresponding to the F1 ATPase, the stator and F0. PMID:18672007

Rak, Malgorzata; Zeng, Xiaomei; Brière, Jean-Jacques; Tzagoloff, Alexander

2009-01-01

18

Transcriptional Regulatory Networks in Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

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

19

Kinetics of Phosphomevalonate Kinase from Saccharomyces cerevisiae  

PubMed Central

The mevalonate-based isoprenoid biosynthetic pathway is responsible for producing cholesterol in humans and is used commercially to produce drugs, chemicals, and fuels. Heterologous expression of this pathway in Escherichia coli has enabled high-level production of the antimalarial drug artemisinin and the proposed biofuel bisabolane. Understanding the kinetics of the enzymes in the biosynthetic pathway is critical to optimize the pathway for high flux. We have characterized the kinetic parameters of phosphomevalonate kinase (PMK, EC 2.7.4.2) from Saccharomyces cerevisiae, a previously unstudied enzyme. An E. coli codon-optimized version of the S. cerevisiae gene was cloned into pET-52b+, then the C-terminal 6X His-tagged protein was expressed in E. coli BL21(DE3) and purified on a Ni2+ column. The KM of the ATP binding site was determined to be 98.3 µM at 30°C, the optimal growth temperature for S. cerevisiae, and 74.3 µM at 37°C, the optimal growth temperature for E. coli. The KM of the mevalonate-5-phosphate binding site was determined to be 885 µM at 30°C and 880 µM at 37°C. The Vmax was determined to be 4.51 µmol/min/mg enzyme at 30°C and 5.33 µmol/min/mg enzyme at 37°C. PMK is Mg2+ dependent, with maximal activity achieved at concentrations of 10 mM or greater. Maximum activity was observed at pH?=?7.2. PMK was not found to be substrate inhibited, nor feedback inhibited by FPP at concentrations up to 10 µM FPP. PMID:24475236

Garcia, David E.; Keasling, Jay D.

2014-01-01

20

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

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunological Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S....

2014-04-01

21

Prediction of Saccharomyces cerevisiae replication origins  

PubMed Central

Background Autonomously replicating sequences (ARSs) function as replication origins in Saccharomyces cerevisiae. ARSs contain the 17 bp ARS consensus sequence (ACS), which binds the origin recognition complex. The yeast genome contains more than 10,000 ACS matches, but there are only a few hundred origins, and little flanking sequence similarity has been found. Thus, identification of origins by sequence alone has not been possible. Results We developed an algorithm, Oriscan, to predict yeast origins using similarity to 26 characterized origins. Oriscan used 268 bp of sequence, including the T-rich ACS and a 3' A-rich region. The predictions identified the exact location of the ACS. A total of 84 of the top 100 Oriscan predictions, and 56% of the top 350, matched known ARSs or replication protein binding sites. The true accuracy was even higher because we tested 25 discrepancies, and 15 were in fact ARSs. Thus, 94% of the top 100 predictions and an estimated 70% of the top 350 were correct. We compared the predictions to corresponding sequences in related Saccharomyces species and found that the ACSs of experimentally supported predictions show significant conservation. Conclusions The high accuracy of the predictions indicates that we have defined near-sufficient conditions for ARS activity, the A-rich region is a recognizable feature of ARS elements with a probable role in replication initiation, and nucleotide sequence is a reliable predictor of yeast origins. Oriscan detected most origins in the genome, demonstrating previously unrecognized generality in yeast replication origins and significant discriminatory power in the algorithm. PMID:15059255

Breier, Adam M; Chatterji, Sourav; Cozzarelli, Nicholas R

2004-01-01

22

The flavoproteome of the yeast Saccharomyces cerevisiae?  

PubMed Central

Genome analysis of the yeast Saccharomyces cerevisiae identified 68 genes encoding flavin-dependent proteins (1.1% of protein encoding genes) to which 47 distinct biochemical functions were assigned. The majority of flavoproteins operate in mitochondria where they participate in redox processes revolving around the transfer of electrons to the electron transport chain. In addition, we found that flavoenzymes play a central role in various aspects of iron metabolism, such as iron uptake, the biogenesis of iron–sulfur clusters and insertion of the heme cofactor into apocytochromes. Another important group of flavoenzymes is directly (Dus1-4p and Mto1p) or indirectly (Tyw1p) involved in reactions leading to tRNA-modifications. Despite the wealth of genetic information available for S. cerevisiae, we were surprised that many flavoproteins are poorly characterized biochemically. For example, the role of the yeast flavodoxins Pst2p, Rfs1p and Ycp4p with regard to their electron donor and acceptor is presently unknown. Similarly, the function of the heterodimeric Aim45p/Cir1p, which is homologous to the electron-transferring flavoproteins of higher eukaryotes, in electron transfer processes occurring in the mitochondrial matrix remains to be elucidated. This lack of information extends to the five membrane proteins involved in riboflavin or FAD transport as well as FMN and FAD homeostasis within the yeast cell. Nevertheless, several yeast flavoproteins, were identified as convenient model systems both in terms of their mechanism of action as well as structurally to improve our understanding of diseases caused by dysfunctional human flavoprotein orthologs. PMID:24373875

Gudipati, Venugopal; Koch, Karin; Lienhart, Wolf-Dieter; Macheroux, Peter

2014-01-01

23

Local Regulatory Variation in Saccharomyces cerevisiae  

PubMed Central

Naturally occurring sequence variation that affects gene expression is an important source of phenotypic differences among individuals within a species. We and others have previously shown that such regulatory variation can occur both at the same locus as the gene whose expression it affects (local regulatory variation) and elsewhere in the genome at trans-acting factors. Here we present a detailed analysis of genome-wide local regulatory variation in Saccharomyces cerevisiae. We used genetic linkage analysis to show that nearly a quarter of all yeast genes contain local regulatory variation between two divergent strains. We measured allele-specific expression in a diploid hybrid of the two strains for 77 genes showing strong self-linkage and found that in 52%–78% of these genes, local regulatory variation acts directly in cis. We also experimentally confirmed one example in which local regulatory variation in the gene AMN1 acts in trans through a feedback loop. Genome-wide sequence analysis revealed that genes subject to local regulatory variation show increased polymorphism in the promoter regions, and that some but not all of this increase is due to polymorphisms in predicted transcription factor binding sites. Increased polymorphism was also found in the 3? untranslated regions of these genes. These findings point to the importance of cis-acting variation, but also suggest that there is a diverse set of mechanisms through which local variation can affect gene expression levels. PMID:16121257

Ronald, James; Brem, Rachel B; Whittle, Jacqueline; Kruglyak, Leonid

2005-01-01

24

Regulation of Cation Balance in Saccharomyces cerevisiae  

PubMed Central

All living organisms require nutrient minerals for growth and have developed mechanisms to acquire, utilize, and store nutrient minerals effectively. In the aqueous cellular environment, these elements exist as charged ions that, together with protons and hydroxide ions, facilitate biochemical reactions and establish the electrochemical gradients across membranes that drive cellular processes such as transport and ATP synthesis. Metal ions serve as essential enzyme cofactors and perform both structural and signaling roles within cells. However, because these ions can also be toxic, cells have developed sophisticated homeostatic mechanisms to regulate their levels and avoid toxicity. Studies in Saccharomyces cerevisiae have characterized many of the gene products and processes responsible for acquiring, utilizing, storing, and regulating levels of these ions. Findings in this model organism have often allowed the corresponding machinery in humans to be identified and have provided insights into diseases that result from defects in ion homeostasis. This review summarizes our current understanding of how cation balance is achieved and modulated in baker’s yeast. Control of intracellular pH is discussed, as well as uptake, storage, and efflux mechanisms for the alkali metal cations, Na+ and K+, the divalent cations, Ca2+ and Mg2+, and the trace metal ions, Fe2+, Zn2+, Cu2+, and Mn2+. Signal transduction pathways that are regulated by pH and Ca2+ are reviewed, as well as the mechanisms that allow cells to maintain appropriate intracellular cation concentrations when challenged by extreme conditions, i.e., either limited availability or toxic levels in the environment. PMID:23463800

Cyert, Martha S.; Philpott, Caroline C.

2013-01-01

25

Expression of Saccharomyces cerevisiae inorganic pyrophosphatase in Escherichia coli.  

PubMed

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

26

THE FUNCTION OF THE CITRIC ACID CYCLE IN SACCHAROMYCES CEREVISIAE  

Microsoft Academic Search

The role of the citric acid cycle in yeast was investigated. ; Suspensions of fasting Saccharomyces cerevisiae were incubated with carbon-14 ; bicarbonate and substrates in a closed vessel connected with a volume ; compensator, and simultaneous measurements of the oxygen consumption were made ; under equal experimental conditions. (C.H.);

A. O. M. Stoppani; S. L. S. de Favelukes; L. Conches; E. Ramos; M. M. Pigretti

1959-01-01

27

Improving biomass sugar utilization by engineered Saccharomyces cerevisiae  

Technology Transfer Automated Retrieval System (TEKTRAN)

The efficient utilization of all available sugars in lignocellulosic biomass, which is more abundant than available commodity crops and starch, represents one of the most difficult technological challenges for the production of bioethanol. The well-studied yeast Saccharomyces cerevisiae has played a...

28

ALCOHOLIC FERMENTATION OF LACTOSE BY ENGINEERED FLOCCULENT SACCHAROMYCES CEREVISIAE  

Microsoft Academic Search

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

P. M. R. Guimarães; J. A. Teixeira; L. Domingues

29

A Novel Function of Saccharomyces cerevisiae CDC5 in Cytokinesis  

Microsoft Academic Search

Coordination of mitotic exit with timely initi- ation of cytokinesis is critical to ensure completion of mitotic events before cell division. The Saccharomyces cerevisiae polo kinase Cdc5 functions in a pathway leading to the degradation of mitotic cyclin Clb2, thereby permitting mitotic exit. Here we provide evi- dence that Cdc5 also plays a role in regulating cytokine- sis and that

Sukgil Song; Kyung S. Lee

2001-01-01

30

Slow growth, stress response and aging in Saccharomyces cerevisiae  

Microsoft Academic Search

The unicellular organism Saccharomyces cerevisiae was used as a modelsystem to study aging at the cellular level. It is known that limiting the amount of calories used by cells can lead to an extension of lifespan. This thesis shows that by applying controlled slow growth circumstances, cells increase their stress response. Besides the increased stress response, also the substance nicotinamide

Victor Jacob Winter

2004-01-01

31

Amino Acid Homeostasis and Chronological Longevity in Saccharomyces cerevisiae  

E-print Network

Chapter 8 Amino Acid Homeostasis and Chronological Longevity in Saccharomyces cerevisiae John P is amino acid homeostasis. Amino acid homeostasis requires three principal functions: amino acid uptake, de novo synthesis, and recycling. Autophagy plays a key role in recycling amino acids and other metabolic

Aris, John P.

32

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

ERIC Educational Resources Information Center

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

33

Transcriptional Response of Saccharomyces cerevisiae to Desiccation and Rehydration  

Microsoft Academic Search

A transcriptional analysis of the response of Saccharomyces cerevisiae strain BY4743 to controlled air-drying (desiccation) and subsequent rehydration under minimal glucose conditions was performed. Expression of genes involved in fatty acid oxidation and the glyoxylate cycle was observed to increase during drying and remained in this state during the rehydration phase. When the BY4743 expression profile for the dried sample

Jatinder Singh; Deept Kumar; Naren Ramakrishnan; Vibha Singhal; Jody Jervis; James F. Garst; Stephen M. Slaughter; Andrea M. DeSantis; Malcolm Potts; Richard F. Helm

2005-01-01

34

The boundaries of the silenced HMR domain in Saccharomyces cerevisiae  

Microsoft Academic Search

The chromosomes of eukaryotes are organized into structurally and functionally discrete domains that provide a mechanism to compact the DNA as well as delineate independent units of gene activity. It is believed that insulator\\/boundary elements separate these domains. Here we report the identification and characterization of boundary elements that flank the transcriptionally repressed HMR locus in the yeast Saccharomyces cerevisiae.

David Donze; Christopher R. Adams; Jasper Rine; Rohinton T. Kamakaka

1999-01-01

35

The genetics of aging in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

The yeastSaccharomyces cerevisiae possesses a finite life span similar in many attributes and implications to that of higher eukaryotes. Here, the measure of the life span is the number of generations or divisions the yeast cell has undergone. The yeast cell is the organism, simplifying many aspects of aging research. Most importantly, the genetics of yeast is highly-developed and readily

S. Michal Jazwinski

1993-01-01

36

Ethanol production from carob pods by Saccharomyces cerevisiae  

Microsoft Academic Search

The production of ethanol from carob pods extract by Saccharomyces cerevisiae in static and shake flask fermentation was investigated. Shake flask fermentation proved to be a better fermentation system for the production of ethanol than static fermentation. The external addition of nutrients into the carob pods extract did not improve the production of ethanol. The maximum concentration of ethanol (75

T. Roukas

1993-01-01

37

Production of lipid compounds in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

This review describes progress using the yeast Saccharomyces cerevisiae as a model organism for the fast and efficient analysis of genes and enzyme activities involved in the lipid biosynthetic pathways of several donor organisms. Furthermore, we assess the impact of baker's yeast on the production of novel, high-value lipid compounds. Yeast can be genetically modified to produce selected substances in

M. Veen; C. Lang

2004-01-01

38

Genetic Analysis of Desiccation Tolerance in Saccharomyces cerevisiae, pp. 507519  

E-print Network

Genetic Analysis of Desiccation Tolerance in Saccharomyces cerevisiae, pp. 507­519 Dean Calahan- tion tolerance in budding yeast that establish it as a powerful genetic system to understand, pp. 561­577 Sang Chul Choi and Jody Hey Although genetic data can be used to determine which

Rosenberg, Noah

39

Endomitotic effect of a cell cycle mutation of Saccharomyces cerevisiae  

Microsoft Academic Search

A recessive temperature-sensitive mutation of Saccharomyces cerevisiae has been isolated and shown to cause an increase in ploidy in both haploids and diploids. Genetic analysis revealed that the strain carrying the mutation was an aa diploid, although MNNG mutagenesis had been done on an a haploid strain. When the mutant strain was crossed with an ..cap alpha cap alpha.. diploid

DAVID SCHILD; HONNAVARA N. ANANTHASWAMY; ROBERT K. MORTIMER

1981-01-01

40

Dynamics of cell wall structure in Saccharomyces cerevisiae  

Microsoft Academic Search

The cell wall of Saccharomyces cerevisiae is an elastic structure that provides osmotic and physical protection and determines the shape of the cell. The inner layer of the wall is largely responsible for the mechanical strength of the wall and also provides the attachment sites for the proteins that form the outer layer of the wall. Here we find among

Frans M Klis; Pieternella Mol; Klaas Hellingwerf

2002-01-01

41

Efficient Extraction of Thioreodoxin from Saccharomyces cerevisiae by Ethanol  

Microsoft Academic Search

Thioredoxin, an antioxidant protein, is a promising molecule for development of functional foods because it protects the gastric mucosa and reduces the allergenicity of allergens. To establish a method for obtaining an ample amount of yeast thioredoxin, we found here that thioredoxin is released from Saccharomyces cerevisiae by treatment with 20% ethanol. We also found that Japanese sake contains a

Yoshiharu Inoue; Wataru Nomura; Yoko Takeuchi; Takumi Ohdate; Shogo Tamasu; Atsushi Kitaoka; Yoshifumi Kiyokawa; Hiroshi Masutani; Kazuo Murata; Yoshinori Wakai; Shingo Izawa; Junji Yodoi

2007-01-01

42

Completion of Replication Map of Saccharomyces cerevisiae Chromosome III  

Microsoft Academic Search

In Saccharomyces cerevisiae chromosomal DNA replication initiates at intervals of 40 kb and depends upon the activity of autonomously replicating sequence (ARS) elements. The identifica- tion 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

Arkadi Poloumienko; Ann Dershowitz; Carol S. Newlon

2001-01-01

43

The AAA3 domain of cytoplasmic dynein acts as a switch to facilitate microtubule release.  

PubMed

Cytoplasmic dynein is an AAA+ motor responsible for intracellular cargo transport and force generation along microtubules (MTs). Unlike kinesin and myosin, dynein contains multiple ATPase subunits, with AAA1 serving as the primary catalytic site. ATPase activity at AAA3 is also essential for robust motility, but its role in dynein's mechanochemical cycle remains unclear. Here, we introduced transient pauses in Saccharomyces cerevisiae dynein motility by using a slowly hydrolyzing ATP analog. Analysis of pausing behavior revealed that AAA3 hydrolyzes nucleotide an order of magnitude more slowly than AAA1, and the two sites do not coordinate. ATPase mutations to AAA3 abolish the ability of dynein to modulate MT release. Nucleotide hydrolysis at AAA3 lifts this 'MT gate' to allow fast motility. These results suggest that AAA3 acts as a switch that repurposes cytoplasmic dynein for fast cargo transport and MT-anchoring tasks in cells. PMID:25486306

DeWitt, Mark A; Cypranowska, Caroline A; Cleary, Frank B; Belyy, Vladislav; Yildiz, Ahmet

2015-01-01

44

Response of Saccharomyces cerevisiae to the Stimulation of Lipopolysaccharide  

PubMed Central

Lipopolysaccharide, known as endotoxin, can stimulate potent host immune responses through the complex of Toll-like-receptor 4 and myeloid differentiation protein 2; but its influence on Saccharomyces cerevisiae, a model organism for studying eukaryotes, is not clear. In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die. Transcriptional profiling of the lipopolysaccharide-treated S. cerevisiae cells showed that 5745 genes were modulated: 2491 genes up-regulated and 3254 genes down-regulated. Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network. Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion. Further experiments demonstrated that lipopolysaccharide stimulation caused the exposure of phosphatidylserine and the increase of mitochondrial membrane potential in S. cerevisiae cells, but levels of intracellular reactive oxygen species and metacaspase activation were not increased. This study demonstrated that lipopolysaccharide stimulation causes significant changes in S. cerevisiae cells, and the results would contribute to understand the response of eukaryotic cells to lipopolysaccharide stimulation. PMID:25105496

Shen, Lulu; Li, Ye; Jiang, Linghuo; Wang, Xiaoyuan

2014-01-01

45

L-Asparaginase of Saccharomyces cerevisiae: an extracellular Enzyme.  

PubMed Central

During recent studies conducted with suspensions of three strains of Saccharomyces cerevisiae, it was observed that ammonia was rapidly liberated when L-asparagine was added to the medium. Subsequent investigation has revealed that these strains of S. cerevisiae have an externally active asparaginase as well as an internally active one. The appearance of the external asparaginase is stimulated by nitrogen starvation, requires an available energy source, and is prevented by cycloheximide. The internal enzyme appears to be constitutive. The external activity is relatively insensitive to para-hydroxymercuribenzoate inhibition, whereas the internal activity is highly inhibited by this compound. PMID:238936

Dunlop, P C; Roon, R J

1975-01-01

46

Statistics-based model for prediction of chemical biosynthesis yield from Saccharomyces cerevisiae  

E-print Network

Background: The robustness of Saccharomyces cerevisiae in facilitating industrial-scale production of ethanol extends its utilization as a platform to synthesize other metabolites. Metabolic engineering strategies, typically ...

Xiao, Yi

47

Investigating the impact of ETP1 in Saccharomyces cerevisiae during Chardonnay fermentation .  

E-print Network

??The wine yeast Saccharomyces cerevisiae experiences a range of stress conditions during wine fermentation. These stresses include osmotic stress, hypoxia, nutrient starvation, cold stress and… (more)

Hillier, Ashley Elizabeth

2013-01-01

48

Purification of Arp2/3 complex from Saccharomyces cerevisiae  

PubMed Central

Summary Much of cellular control over actin dynamics comes through regulation of actin filament initiation. At the molecular level, this is accomplished through a collection of cellular protein machines, called actin nucleation factors, which position actin monomers to initiate a new actin filament. The Arp2/3 complex is a principal actin nucleation factor used throughout the eukaryotic family tree. The budding yeast Saccharomyces cerevisiae has proven to be not only an excellent genetic platform for the study of the Arp2/3 complex, but also an excellent source for the purification of endogenous Arp2/3 complex. Here we describe a protocol for the preparation of endogenous Arp2/3 complex from wild type Saccharomyces cerevisiae. This protocol produces material suitable for biochemical study, and yields milligram quantities of purified Arp2/3 complex. PMID:23868593

Doolittle, Lynda K.; Rosen, Michael K.; Padrick, Shae B.

2014-01-01

49

Clustering of the Genes for Allantoin Degradation in Saccharomyces cerevisiae  

PubMed Central

We have shown that allantoin degradation in Saccharomyces cerevisiae proceeds exclusively through the intermediate formation of allantoic acid, urea, and allophanic acid. The number of reactions between allantoic acid and urea, however, remains obscure owing to our inability to isolate a mutant defective in ureidoglycolate hydrolase. Structural genes for the enzymes, allantoinase (dal1) and allantoicase (dal2) are located on chromosome IX promixal to the centromere in the order dal1-dal2-lysl. PMID:4604238

Lawther, Robert P.; Riemer, Elaine; Chojnacki, Bonnie; Cooper, Terrance G.

1974-01-01

50

Switching the mode of sucrose utilization by Saccharomyces cerevisiae  

Microsoft Academic Search

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

Fernanda Badotti; Marcelo G Dário; Sergio L Alves Jr; Maria Luiza A Cordioli; Luiz C Miletti; Pedro S de Araujo; Boris U Stambuk

2008-01-01

51

Global landscape of protein complexes in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

Identification of protein–protein interactions often provides insight into protein function, and many cellular processes are performed by stable protein complexes. We used tandem affinity purification to process 4,562 different tagged proteins of the yeast Saccharomyces cerevisiae. Each preparation was analysed by both matrix-assisted laser desorption\\/ionization–time of flight mass spectrometry and liquid chromatography tandem mass spectrometry to increase coverage and accuracy.

Nevan J. Krogan; Gerard Cagney; Haiyuan Yu; Gouqing Zhong; Xinghua Guo; Alexandr Ignatchenko; Joyce Li; Shuye Pu; Nira Datta; Aaron P. Tikuisis; Thanuja Punna; José M. Peregrín-Alvarez; Michael Shales; Xin Zhang; Michael Davey; Mark D. Robinson; Alberto Paccanaro; James E. Bray; Anthony Sheung; Bryan Beattie; Dawn P. Richards; Veronica Canadien; Atanas Lalev; Frank Mena; Peter Wong; Andrei Starostine; Myra M. Canete; James Vlasblom; Samuel Wu; Chris Orsi; Sean R. Collins; Shamanta Chandran; Robin Haw; Jennifer J. Rilstone; Kiran Gandi; Natalie J. Thompson; Gabe Musso; Peter St Onge; Shaun Ghanny; Mandy H. Y. Lam; Gareth Butland; Amin M. Altaf-Ul; Shigehiko Kanaya; Ali Shilatifard; Erin O'Shea; Jonathan S. Weissman; C. James Ingles; Timothy R. Hughes; John Parkinson; Mark Gerstein; Shoshana J. Wodak; Andrew Emili; Jack F. Greenblatt

2006-01-01

52

PGM2 overexpression improves anaerobic galactose fermentation in Saccharomyces cerevisiae  

Microsoft Academic Search

BACKGROUND: In Saccharomyces cerevisiae galactose is initially metabolized through the Leloir pathway after which glucose 6-phosphate enters glycolysis. Galactose is controlled both by glucose repression and by galactose induction. The gene PGM2 encodes the last enzyme of the Leloir pathway, phosphoglucomutase 2 (Pgm2p), which catalyses the reversible conversion of glucose 1-phosphate to glucose 6-phosphate. Overexpression of PGM2 has previously been

Rosa Garcia Sanchez; Bärbel Hahn-Hägerdal; Marie F Gorwa-Grauslund

2010-01-01

53

Calorie restriction extends Saccharomyces cerevisiae lifespan by increasing respiration  

Microsoft Academic Search

Calorie restriction (CR) extends lifespan in a wide spectrum of organisms and is the only regimen known to lengthen the lifespan of mammals. We established a model of CR in budding yeast Saccharomyces cerevisiae. In this system, lifespan can be extended by limiting glucose or by reducing the activity of the glucose-sensing cyclic-AMP-dependent kinase (PKA). Lifespan extension in a mutant

Su-Ju Lin; Matt Kaeberlein; Alex A. Andalis; Lori A. Sturtz; Pierre-Antoine Defossez; Valeria C. Culotta; Gerald R. Fink; Leonard Guarente

2002-01-01

54

A Saccharomyces cerevisiae-based bioassay for assessing pesticide toxicity.  

PubMed

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

55

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

PubMed Central

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. cerevisiae 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 × 105 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. PMID:25242923

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

2014-01-01

56

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

PubMed

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. cerevisiae 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 × 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. PMID:25242923

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

2014-01-01

57

Saccharomyces cerevisiae engineered for xylose metabolism exhibits a respiratory response.  

PubMed

Native strains of Saccharomyces cerevisiae do not assimilate xylose. S. cerevisiae engineered for d-xylose utilization through the heterologous expression of genes for aldose reductase (XYL1), xylitol dehydrogenase (XYL2), and d-xylulokinase (XYL3 or XKS1) produce only limited amounts of ethanol in xylose medium. In recombinant S. cerevisiae expressing XYL1, XYL2, and XYL3, mRNA transcript levels for glycolytic, fermentative, and pentose phosphate enzymes did not change significantly on glucose or xylose under aeration or oxygen limitation. However, expression of genes encoding the tricarboxylic acid cycle, respiration enzymes (HXK1, ADH2, COX13, NDI1, and NDE1), and regulatory proteins (HAP4 and MTH1) increased significantly when cells were cultivated on xylose, and the genes for respiration were even more elevated under oxygen limitation. These results suggest that recombinant S. cerevisiae does not recognize xylose as a fermentable carbon source and that respiratory proteins are induced in response to cytosolic redox imbalance; however, lower sugar uptake and growth rates on xylose might also induce transcripts for respiration. A petite respiration-deficient mutant (rho degrees ) of the engineered strain produced more ethanol and accumulated less xylitol from xylose. It formed characteristic colonies on glucose, but it did not grow on xylose. These results are consistent with the higher respiratory activity of recombinant S. cerevisiae when growing on xylose and with its inability to grow on xylose under anaerobic conditions. PMID:15528549

Jin, Yong-Su; Laplaza, Jose M; Jeffries, Thomas W

2004-11-01

58

Desferrioxamine-mediated Iron Uptake in Saccharomyces cerevisiae EVIDENCE FOR TWO PATHWAYS OF IRON UPTAKE*  

E-print Network

Desferrioxamine-mediated Iron Uptake in Saccharomyces cerevisiae EVIDENCE FOR TWO PATHWAYS OF IRON Medical Institute, Stanford, California 94305-5428 In the yeast Saccharomyces cerevisiae, uptake of iron is largely regulated by the transcription factor Aft1. cDNA microarrays were used to identify new iron

Botstein, David

59

Whole-genome expression analysis of snf swi mutants of Saccharomyces cerevisiae  

E-print Network

Whole-genome expression analysis of snf swi mutants of Saccharomyces cerevisiae Priya Sudarsanam (received for review September 22, 1999) The Saccharomyces cerevisiae Snf Swi complex has been previ- ously mutants deleted for a gene encoding one conserved (Snf2) or one unconserved (Swi1) Snf Swi component

Ghosh, Joydeep

60

Crystal structure of the heterotrimer core of Saccharomyces cerevisiae AMPK homologue SNF1  

E-print Network

LETTERS Crystal structure of the heterotrimer core of Saccharomyces cerevisiae AMPK homologue SNF1, obesity and other diseases1­5 . The AMPK homologue in Saccharomyces cerevisiae, known as SNF1, is essential for responses to glucose starvation as well as for other cellular processes, although SNF1 seems

Tong, Liang

61

Phosphoenolpyruvate Carboxykinase as the Sole Anaplerotic Enzyme in Saccharomyces cerevisiae?  

PubMed Central

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

62

A screen for dynein synthetic lethals in Aspergillus nidulans identifies spindle assembly checkpoint genes and other genes involved in mitosis.  

PubMed Central

Cytoplasmic dynein is a ubiquitously expressed microtubule motor involved in vesicle transport, mitosis, nuclear migration, and spindle orientation. In the filamentous fungus Aspergillus nidulans, inactivation of cytoplasmic dynein, although not lethal, severely impairs nuclear migration. The role of dynein in mitosis and vesicle transport in this organism is unclear. To investigate the complete range of dynein function in A. nidulans, we searched for synthetic lethal mutations that significantly reduced growth in the absence of dynein but had little effect on their own. We isolated 19 sld (synthetic lethality without dynein) mutations in nine different genes. Mutations in two genes exacerbate the nuclear migration defect seen in the absence of dynein. Mutations in six other genes, including sldA and sldB, show a strong synthetic lethal interaction with a mutation in the mitotic kinesin bimC and, thus, are likely to play a role in mitosis. Mutations in sldA and sldB also confer hypersensitivity to the microtubule-destabilizing drug benomyl. sldA and sldB were cloned by complementation of their mutant phenotypes using an A. nidulans autonomously replicating vector. Sequencing revealed homology to the spindle assembly checkpoint genes BUB1 and BUB3 from Saccharomyces cerevisiae. Genetic interaction between dynein and spindle assembly checkpoint genes, as well as other mitotic genes, indicates that A. nidulans dynein plays a role in mitosis. We suggest a model for dynein motor action in A. nidulans that can explain dynein involvement in both mitosis and nuclear distribution. PMID:9584089

Efimov, V P; Morris, N R

1998-01-01

63

Overproduction of fatty acids in engineered Saccharomyces cerevisiae.  

PubMed

The long hydrocarbon fatty acyl chain is energy rich, making it an ideal precursor for liquid transportation fuels and high-value oleo chemicals. As Saccharomyces cerevisiae has many advantages for industrial production compared to Escherichia coli. Here, we attempted to engineer Saccharomyces cerevisiae for overproduction of fatty acids. First, disruption of the beta-oxidation pathway, elimination of the acyl-CoA synthetases, overexpression of different thioesterases and acetyl-CoA carboxylase ACC1, and engineering the supply of precursor acetyl-CoA. The engineered strain XL122 produced more than 120 mg/L of fatty acids. In parallel, we inactivated ADH1, the dominant gene for ethanol production, to redirect the metabolic flux to fatty acids synthesis. The engineered strain DG005 produced about 140 mg/L fatty acids. Additionally, Acetyl-CoA carboxylase was identified as a critical bottleneck of fatty acids synthesis in S. cerevisiae with a cell-free system. However, overexpression of ACC1 has little effect on fatty acids biosynthesis. As it has been reported that phosphorylation of ACC1 may influent its activity, so phosphorylation sites of ACC1 were further identified. Although the regulatory mechanisms remain unclear, our results provide rationale for future studies to target this critical step. All these efforts, particularly the discovery of the limiting step are critical for developing a "cell factory" for the overproduction of fatty acids by using type I fatty acids synthase in yeast or other fungi. PMID:24752690

Li, Xiaowei; Guo, Daoyi; Cheng, Yongbo; Zhu, Fayin; Deng, Zixin; Liu, Tiangang

2014-09-01

64

Fenpropimorph affects uptake of uracil and cytosine in Saccharomyces cerevisiae.  

PubMed Central

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 a significant decrease in the uptake of radiolabeled uracil, which was not due to accumulation of ergosta-8,14-dienol (ignosterol) in the treated cultures. Radiolabeled cytosine uptake was unaffected by drug treatment in a wild-type strain but was inhibited in a sterol mutant, in which ergosterol was absent from the cell. The role of fenpropimorph in causing membrane dysfunction through a mechanism other than altered sterol metabolism is discussed. PMID:8067730

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

1994-01-01

65

Calcium ion influx during sporulation in the yeast Saccharomyces cerevisiae.  

PubMed

The changes in intra- and (or) extra-cellular concentrations of Ca2+, Mg2+, K+, and Na+ during sporulation of a MATa/MAT alpha diploid yeast of Saccharomyces cerevisiae were examined in a nutrition-deprived medium with potassium acetate. Among these, Ca2+ in external medium was preferentially incorporated into cells, and sporulation was induced when the magnitude of free Ca2+ gradient between cytosol [Ca2+]i and external medium [Ca2+]o reached more than 3 x 10(3) ([Ca2+]i/[Ca2+]o = 3.5 x 10(3)). The result indicated that the meiosis and (or) sporulation signal of the yeast S. cerevisiae was generated through elevated Ca2+ influx rather than release from the internal Ca2+ stores. PMID:7497351

Suizu, T; Tsutsumi, H; Kawado, A; Suginami, K; Imayasu, S; Murata, K

1995-11-01

66

ROG1 encodes a monoacylglycerol lipase in Saccharomyces cerevisiae.  

PubMed

Lipid metabolism is extensively studied in Saccharomyces cerevisiae. Here, we report that revertant of glycogen synthase kinase mutation-1 (Rog1p) possesses monoacylglycerol (MAG) lipase activity in S. cerevisiae. The lipase activity of Rog1p was confirmed in two ways: through analysis of a strain with a double deletion of ROG1 and monoglyceride lipase YJU3 (yju3?rog1?) and by site-directed mutagenesis of the ROG1 lipase motif (GXSXG). Rog1p is localized in both the cytosol and the nucleus. Overexpression of ROG1 in a ROG1-deficient strain resulted in an accumulation of reactive oxygen species. These results suggest that Rog1p is a MAG lipase that regulates lipid homeostasis. PMID:25433290

Vishnu Varthini, Lakshmanaperumal; Selvaraju, Kandasamy; Srinivasan, Malathi; Nachiappan, Vasanthi

2015-01-01

67

SACCHAROMYCES CEREVISIAE Recessive Suppressor That Circumvents Phosphatidylserine Deficiency  

PubMed Central

Phenotypic reversion of six independent Saccharomyces cerevisiae cho1 mutants was shown to be due predominantly to mutation of an unlinked gene, eam1. The eam1 gene was located very close to ino1 on chromosome X by meiotic tetrad analysis. Recessive eam1 mutations did not correct the primary cho1 defect in phosphatidylserine synthesis but made endogenous ethanolamine available for sustained nitrogenous phospholipid synthesis. A novel biochemical contribution to nitrogenous lipid synthesis is indicated by the eam1 mutants. PMID:17246236

Atkinson, Katharine D.

1984-01-01

68

Discontinuity Induced Bifurcations in a Model of Saccharomyces cerevisiae  

E-print Network

We perform a bifurcation analysis of the mathematical model of Jones and Kompala [K.D. Jones and D.S. Kompala, Cybernetic model of the growth dynamics of Saccharomyces cerevisiae in batch and continuous cultures, J. Biotech., 71:105-131, 1999]. Stable oscillations arise via Andronov-Hopf bifurcations and exist for intermediate values of the dilution rate as has been noted from experiments previously. A variety of discontinuity induced bifurcations arise from a lack of global differentiability. We identify and classify discontinuous bifurcations including several codimension-two scenarios. Bifurcation diagrams are explained by a general unfolding of these singularities.

D. J. W. Simpson; D. S. Kompala; J. D. Meiss

2008-07-01

69

Calcium uptake during the cell cycle of Saccharomyces cerevisiae.  

PubMed

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

70

Nutritional Control via Tor signaling in Saccharomyces cerevisiae  

PubMed Central

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 delineate distinct signaling branches emanating from membrane associated Tor complexes to control cell growth. PMID:18396450

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

2008-01-01

71

Transcriptional silencing in Saccharomyces cerevisiae and Schizosaccharomyces pombe  

PubMed Central

Transcriptional silencing is a heritable form of gene inactivation that involves the assembly of large regions of DNA into a specialized chromatin structure that inhibits transcription. This phenomenon is responsible for inhibiting transcription at silent mating-type loci, telomeres and rDNA repeats in both budding yeast Saccharomyces cerevisiae and fission yeast Schizosaccharomyces pombe, as well as at centromeres in fission yeast. Although transcriptional silencing in both S.cerevisiae and S.pombe involves modification of chromatin, no apparent amino acid sequence similarities have been reported between the proteins involved in establishment and maintenance of silent chromatin in these two distantly related yeasts. Silencing in S.cerevisiae is mediated by Sir2p-containing complexes, whereas silencing in S.pombe is mediated primarily by Swi6-containing complexes. The Swi6 complexes of S.pombe contain proteins closely related to their counterparts in higher eukaryotes, but have no apparent orthologs in S.cerevisiae. Silencing proteins from both yeasts are also actively involved in other chromosome-related nuclear functions, including DNA repair and the regulation of chromatin structure. PMID:11917007

Huang, Ying

2002-01-01

72

TRIPLES: a database of gene function in Saccharomyces cerevisiae  

PubMed Central

Using a novel multipurpose mini-transposon, we have generated a collection of defined mutant alleles for the analysis of disruption phenotypes, protein localization, and gene expression in Saccharomyces cerevisiae. To catalog this unique data set, we have developed TRIPLES, a Web-accessible database of TRansposon-Insertion Phenotypes, Localization and Expression in Saccharomyces. Encompassing over 250 000 data points, TRIPLES provides convenient access to information from nearly 7800 transposon-mutagenized yeast strains; within TRIPLES, complete data reports of each strain may be viewed in table format, or if desired, downloaded as tab-delimited text files. Each report contains external links to corresponding entries within the Saccharomyces Genome Database and International Nucleic Acid Sequence Data Library (GenBank). Unlike other yeast databases, TRIPLES also provides on-line order forms linked to each clone report; users may immediately request any desired strain free-of-charge by submitting a completed form. In addition to presenting a wealth of information for over 2300 open reading frames, TRIPLES constitutes an important medium for the distribution of useful reagents throughout the yeast scientific community. Maintained by the Yale Genome Analysis Center, TRIPLES may be accessed at http://ycmi.med.yale.edu/ygac/triples.htm PMID:10592187

Kumar, Anuj; Cheung, Kei-Hoi; Ross-Macdonald, Petra; Coelho, Paulo S. R.; Miller, Perry; Snyder, Michael

2000-01-01

73

Ciclohexadespipeptide beauvericin degradation by different strains of Saccharomyces cerevisiae.  

PubMed

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

74

Biogeographical characterization of Saccharomyces cerevisiae wine yeast by molecular methods.  

PubMed

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." 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 flavor 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. PMID:23805132

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

2013-01-01

75

Biogeographical characterization of Saccharomyces cerevisiae wine yeast by molecular methods  

PubMed Central

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.” 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 flavor 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. PMID:23805132

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

2013-01-01

76

Role of social wasps in Saccharomyces cerevisiae ecology and evolution.  

PubMed

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

77

Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model  

PubMed Central

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. PMID:25584613

Feyder, Serge; De Craene, Johan-Owen; Bär, Séverine; Bertazzi, Dimitri L.; Friant, Sylvie

2015-01-01

78

Transcriptional profiling of Saccharomyces cerevisiae exposed to propolis  

PubMed Central

Background Propolis is a natural product of plant resins collected by honeybees (Apis mellifera) from various plant sources. Our previous studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis. Here, we extended our understanding of propolis-mediated cell death in the yeast Saccharomyces cerevisiae by applying systems biology tools to analyze the transcriptional profiling of cells exposed to propolis. Methods We have used transcriptional profiling of S. cerevisiae exposed to propolis. We validated our findings by using real-time PCR of selected genes. Systems biology tools (physical protein-protein interaction [PPPI] network) were applied to analyse the propolis-induced transcriptional bevavior, aiming to identify which pathways are modulated by propolis in S. cerevisiae and potentially influencing cell death. Results We were able to observe 1,339 genes modulated in at least one time point when compared to the reference time (propolis untreated samples) (t-test, p-value 0.01). Enrichment analysis performed by Gene Ontology (GO) Term finder tool showed enrichment for several biological categories among the genes up-regulated in the microarray hybridization such as transport and transmembrane transport and response to stress. Real-time RT-PCR analysis of selected genes showed by our microarray hybridization approach was capable of providing information about S. cerevisiae gene expression modulation with a considerably high level of confidence. Finally, a physical protein-protein (PPPI) network design and global topological analysis stressed the importance of these pathways in response of S. cerevisiae to propolis and were correlated with the transcriptional data obtained thorough the microarray analysis. Conclusions In summary, our data indicate that propolis is largely affecting several pathways in the eukaryotic cell. However, the most prominent pathways are related to oxidative stress, mitochondrial electron transport chain, vacuolar acidification, regulation of macroautophagy associated with protein target to vacuole, cellular response to starvation, and negative regulation of transcription from RNA polymerase II promoter. Our work emphasizes again the importance of S. cerevisiae as a model system to understand at molecular level the mechanism whereby propolis causes cell death in this organism at the concentration herein tested. Our study is the first one that investigates systematically by using functional genomics how propolis influences and modulates the mRNA abundance of an organism and may stimulate further work on the propolis-mediated cell death mechanisms in fungi. PMID:23092287

2012-01-01

79

Defining the active form of ribonucleotide reductase from Saccharomyces cerevisiae in vitro and in vivo  

E-print Network

Ribonucleotide reductase (RNR) catalyzes the conversion of ribonucleotides to deoxyribonucleotides. Saccharomyces cerevisiae RNR is a class I RNR composed of a dimeric large subunit (RI), containing the active site and ...

Perlstein, Deborah Leigh

2005-01-01

80

Saccharomyces cerevisiae live cells stimulate degradation and fermentation of cellulose by the rumen anaerobic  

E-print Network

Saccharomyces cerevisiae live cells stimulate degradation and fermentation of cellulose fermentation patterns and to increase numbers of rumen bacteria, especially cellulolytic species (Wallace and fermentation of cellulose by an anaerobic fungus, Neocallimastix frontalis MCH3, which is particularly

Paris-Sud XI, Université de

81

Functional attributes of the Saccharomyces cerevisiae meiotic recombinase Dmc1.  

PubMed

The role of Dmc1 as a meiosis-specific general recombinase was first demonstrated in Saccharomyces cerevisiae. Progress in understanding the biochemical mechanism of ScDmc1 has been hampered by its tendency to form inactive aggregates. We have found that the inclusion of ATP during protein purification prevents Dmc1 aggregation. ScDmc1 so prepared is capable of forming D-loops and responsive to its accessory factors Rad54 and Rdh54. Negative staining electron microscopy and iterative helical real-space reconstruction revealed that the ScDmc1-ssDNA nucleoprotein filament harbors 6.5 protomers per turn with a pitch of ?106?. The ScDmc1 purification procedure and companion molecular analyses should facilitate future studies on this recombinase. PMID:23769192

Busygina, Valeria; Gaines, William A; Xu, Yuanyuan; Kwon, Youngho; Williams, Gareth J; Lin, Sheng-Wei; Chang, Hao-Yen; Chi, Peter; Wang, Hong-Wei; Sung, Patrick

2013-09-01

82

Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress  

PubMed Central

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

83

A simple method for isolating disomic strains of Saccharomyces cerevisiae  

PubMed Central

A simple method to select disomic (N + 1) strains that should be applicable for almost any chromosome in Saccharomyces cerevisiae is presented. A diploid heterozygous for a KanMX knock-out mutation in an essential gene is sporulated and viable geneticin (G418)-resistant colonies selected. Disomic products of a missegregation or non-disjunction event containing a copy of both the wild-type essential gene and its complementary KanMX knock-out allele make up most of the viable colonies. This method has been used to isolate disomic haploids for a variety of chromosomes. It is appropriately named MARV (for missegregation-associated restoration of viability) and is easily adaptable to virtually any strain. PMID:18437703

Zebrowski, David C.; Kaback, David B.

2014-01-01

84

Influence of killer strains of Saccharomyces cerevisiae on wine fermentation.  

PubMed

The effect of killer strains of Saccharomyces cerevisiae on the growth of sensitive strains during must fermentation was studied by using a new method to monitor yeast populations. The capability of killer yeast strains to eliminate sensitive strains depends on the initial proportion of killer yeasts, the susceptibility of sensitive strains, and the treatment of the must. In sterile filtered must, an initial proportion of 2-6% of killer yeasts was responsible for protracted fermentation and suppression of isogenic sensitive strains. A more variable initial proportion was needed to get the same effect with non-isogenic strains. The suspended solids that remain in the must after cold-settling decreased killer toxin effect. The addition of bentonite to the must avoided protracted fermentation and the suppression of sensitive strains; however, the addition of yeast dietary nutrients with yeast cell walls did not, although it decreased fermentation lag. PMID:11816985

Pérez, F; Ramírez, M; Regodón, J A

2001-09-01

85

Saccharomyces cerevisiae Yta7 Regulates Histone Gene Expression  

PubMed Central

The Saccharomyces cerevisiae Yta7 protein is a component of a nucleosome bound protein complex that maintains distinct transcriptional zones of chromatin. We previously found that one protein copurifying with Yta7 is the yFACT member Spt16. Epistasis analyses revealed a link between Yta7, Spt16, and other previously identified members of the histone regulatory pathway. In concurrence, Yta7 was found to regulate histone gene transcription in a cell-cycle-dependent manner. Association at the histone gene loci appeared to occur through binding of the bromodomain-like region of Yta7 with the N-terminal tail of histone H3. Our work suggests a mechanism in which Yta7 is localized to chromatin to establish regions of transcriptional silencing, and that one facet of this cellular mechanism is to modulate transcription of histone genes. PMID:18493054

Gradolatto, Angeline; Rogers, Richard S.; Lavender, Heather; Taverna, Sean D.; Allis, C. David; Aitchison, John D.; Tackett, Alan J.

2008-01-01

86

Saccharomyces cerevisiae and Neurospora crassa contain heavy metal sequestering phytochelatin.  

PubMed

In fungi, cellular resistance to heavy metal cytotoxicity is mediated either by binding of metal ions to proteins of the metallothionein type or by chelation to phytochelatin-peptides of the general formula (gamma-Glu-Cys)n-Gly. Hitherto, only one fungus, Candida glabrata has been shown to contain both metal inactivating systems. Here we show by unambiguous FAB-MS analysis that both a metallothionein-free mutant of Saccharomyces cerevisiae as well as a wildtype strain synthesize phytochelatin (PC2) upon exposure to 250 microM Cd2+ ions. The presence of Zn and/or Cu ions in the nutrient broth also induces PC2 synthesis in this organism. By 109Cd exchange and subsequent monobromobimane fluorescence HPLC, it could be shown that the presence of Cd2+ in the growth medium also induces phytochelatin synthesis in Neurospora crassa, which contains metallothioneins. PMID:1534214

Kneer, R; Kutchan, T M; Hochberger, A; Zenk, M H

1992-01-01

87

Intracellular ethanol accumulation in Saccharomyces cerevisiae during fermentation.  

PubMed Central

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 after 12 h of fermentation. Increasing the osmotic pressure also caused a decrease in yeast cell growth and fermentation activities. However, nutrient supplementation of the medium increased the extent of growth and fermentation, resulting in complete glucose utilization, even though intracellular ethanol concentrations were unaltered. These results suggest that nutrient limitation is a major factor responsible for the decreased growth and fermentation activities observed in yeast cells at higher osmotic pressures. PMID:3278685

D'Amore, T; Panchal, C J; Stewart, G G

1988-01-01

88

Mechanisms and Regulation of Mitotic Recombination in Saccharomyces cerevisiae  

PubMed Central

Homology-dependent exchange of genetic information between DNA molecules has a profound impact on the maintenance of genome integrity by facilitating error-free DNA repair, replication, and chromosome segregation during cell division as well as programmed cell developmental events. This chapter will focus on homologous mitotic recombination in budding yeast Saccharomyces cerevisiae. However, there is an important link between mitotic and meiotic recombination (covered in the forthcoming chapter by Hunter et al. 2015) and many of the functions are evolutionarily conserved. Here we will discuss several models that have been proposed to explain the mechanism of mitotic recombination, the genes and proteins involved in various pathways, the genetic and physical assays used to discover and study these genes, and the roles of many of these proteins inside the cell. PMID:25381364

Symington, Lorraine S.; Rothstein, Rodney; Lisby, Michael

2014-01-01

89

Bioaccumulation of cadmium by growing Zygosaccharomyces rouxii and Saccharomyces cerevisiae.  

PubMed

Bioaccumulation via growing cells is a potential technique for heavy metal removal from food materials. The cadmium bioaccumulation characteristics by growing Zygosaccharomyces rouxii and Saccharomyces cerevisiae were investigated. Z. rouxii displayed powerful cadmium removal ability at low cadmium concentrations, which mainly depended on the intracellular cadmium bioaccumulation. The percentage of intracellular cadmium bioaccumulation of both yeasts obviously decreased with the increase of initial biomass and cadmium concentrations. Low pH and elevated concentrations of zinc and copper significantly decreased the intracellular cadmium bioaccumulation of both yeasts but improved the cadmium tolerance and the cell-surface cadmium bioaccumulation of Z. rouxii. Cadmium removal of Z. rouxii was improved by zinc and copper conditionally. Z. rouxii that possessed more powerful cadmium tolerance and removal ability at low pH and high concentration of competing ions can be developed into a potential cadmium removal agent using in complex food environment in future. PMID:24440489

Li, Chunsheng; Jiang, Wei; Ma, Ning; Zhu, Yinglian; Dong, Xiaoyan; Wang, Dongfeng; Meng, Xianghong; Xu, Ying

2014-03-01

90

Crystallization of a mammalian membrane protein overexpressed in Saccharomyces cerevisiae  

PubMed Central

The Ca2+-ATPase SERCA1a (sarcoplasmic–endoplasmic reticulum Ca2+-ATPase isoform 1a) from rabbit has been overexpressed in Saccharomyces cerevisiae. This membrane protein was purified by avidin agarose affinity chromatography based on natural biotinylation in the expression host, followed by HPLC gel filtration. Both the functional and structural properties of the overexpressed protein validate the method. Thus, calcium-dependent ATPase activity and calcium transport are essentially intact after reconstitution in proteoliposomes. Moreover, the recombinant protein crystallizes in a form that is isomorphous to the native SERCA1a protein from rabbit, and the diffraction properties are similar. This represents a successful crystallization of a mammalian membrane protein derived from a heterologous expression system, and it opens the way for the study of mutant forms of SERCA1a. PMID:16087876

Jidenko, Marie; Nielsen, Rikke C.; Sørensen, Thomas Lykke-Møller; Møller, Jesper V.; le Maire, Marc; Nissen, Poul; Jaxel, Christine

2005-01-01

91

Water treatment process and system for metals removal using Saccharomyces cerevisiae  

DOEpatents

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

92

Complete nucleotide sequence of Saccharomyces cerevisiae chromosome X.  

PubMed Central

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome X (745 442 bp) reveals a total of 379 open reading frames (ORFs), the coding region covering approximately 75% of the entire sequence. One hundred and eighteen ORFs (31%) correspond to genes previously identified in S. cerevisiae. All other ORFs represent novel putative yeast genes, whose function will have to be determined experimentally. However, 57 of the latter subset (another 15% of the total) encode proteins that show significant analogy to proteins of known function from yeast or other organisms. The remaining ORFs, exhibiting no significant similarity to any known sequence, amount to 54% of the total. General features of chromosome X are also reported, with emphasis on the nucleotide frequency distribution in the environment of the ATG and stop codons, the possible coding capacity of at least some of the small ORFs (<100 codons) and the significance of 46 non-canonical or unpaired nucleotides in the stems of some of the 24 tRNA genes recognized on this chromosome. Images PMID:8641269

Galibert, F; Alexandraki, D; Baur, A; Boles, E; Chalwatzis, N; Chuat, J C; Coster, F; Cziepluch, C; De Haan, M; Domdey, H; Durand, P; Entian, K D; Gatius, M; Goffeau, A; Grivell, L A; Hennemann, A; Herbert, C J; Heumann, K; Hilger, F; Hollenberg, C P; Huang, M E; Jacq, C; Jauniaux, J C; Katsoulou, C; Karpfinger-Hartl, L

1996-01-01

93

Induction and inhibition of the allantoin permease in Saccharomyces cerevisiae.  

PubMed Central

Allantoin uptake in Saccharomyces cerevisiae is mediated by an energy-dependent, low-Km, active transport system. However, there is at present little information concerning its regulation. In view of this, we investigated the control of alloantoin transport and found that it was regulated quite differently from the other pathway components. Preincubation of appropriate mutant cultures with purified allantoate (commercial preparations contain 17% allantoin), urea, or oxalurate did not significantly increase allantoin uptake. Preincubation with allantoin, however, resulted in a 10- to 15-fold increase in the rate of allantoin accumulation. Two allantoin analogs were also found to elicit dramatic increases in allantoin uptake. Hydantoin and hydantoin acetic acid were able to induce allantoin transport to 63 and 95% of the levels observed with allantoin. Neither of these compounds was able to serve as a sole nitrogen source for S. cerevisiae, and they may be non-metabolizable inducers of the allantoin permease. The rna1 gene product appeared to be required for allantoin permease induction, suggesting that control was exerted at the level of gene expression. In addition, we have shown that allantoin uptake is not unidirectional; efflux merely occurs at a very low rate. Allantoin uptake is also transinhibited by addition of certain amino acids to the culture medium, and several models concerning the operation of such inhibition were discussed. PMID:355231

Sumrada, R; Zacharski, C A; Turoscy, V; Cooper, T G

1978-01-01

94

Transcriptional regulation by ergosterol in the yeast Saccharomyces cerevisiae.  

PubMed Central

Sterol biosynthesis in the yeast Saccharomyces cerevisiae is an energy-expensive, aerobic process, requiring heme and molecular oxygen. Heme, also synthesized exclusively during aerobic growth, not only acts as an enzymatic cofactor but also is directly and indirectly responsible for the transcriptional control of several yeast genes. Because of their biosynthetic similarities, we hypothesized that ergosterol, like heme, may have a regulatory function. Sterols are known to play a structural role in membrane integrity, but regulatory roles have not been characterized. To test possible regulatory roles of sterol, the promoter for the ERG3 gene, encoding the sterol C-5 desaturase, was fused to the bacterial lacZ reporter gene. This construct was placed in strains making aberrant sterols, and the effect of altered sterol composition on gene expression was monitored by beta-galactosidase activity. The absence of ergosterol resulted in a 35-fold increase in the expression of ERG3 as measured by beta-galactosidase activity. The level of ERG3 mRNA was increased as much as ninefold in erg mutant strains or wild-type strains inhibited in ergosterol biosynthesis by antifungal agents. The observed regulatory effects of ergosterol on ERG3 are specific for ergosterol, as several ergosterol derivatives failed to elicit the same controlling effect. These results demonstrate for the first time that ergosterol exerts a regulatory effect on gene transcription in S. cerevisiae. PMID:8816455

Smith, S J; Crowley, J H; Parks, L W

1996-01-01

95

Quantifying separation and similarity in a Saccharomyces cerevisiae metapopulation.  

PubMed

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

96

Identification of a Saccharomyces cerevisiae glucosidase that hydrolyzes flavonoid glucosides.  

PubMed

Baker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-?-glucoside revealed considerable ?-glucosidase activity, which impairs any strategy to generate or modify flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in the S. cerevisiae genome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic ?- or ?-glucosides identified three efficient ?-glucosidases (EXG1, SPR1, and YIR007W), which were further assayed with natural flavonoid ?-glucoside substrates and product verification by thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Preferential hydrolysis of 7- or 4'-O-glucosides of isoflavones, flavonols, flavones, and flavanones was observed in vitro with all three glucosidases, while anthocyanins were also accepted as substrates. The glucosidase activities of EXG1 and SPR1 were completely abolished by Val168Tyr mutation, which confirmed the relevance of this residue, as reported for other glucosidases. Most importantly, biotransformation experiments with knockout yeast strains revealed that only EXG1 knockout strains lost the capability to hydrolyze flavonoid glucosides. PMID:21216897

Schmidt, Sabine; Rainieri, Sandra; Witte, Simone; Matern, Ulrich; Martens, Stefan

2011-03-01

97

Quantifying separation and similarity in a Saccharomyces cerevisiae metapopulation  

PubMed Central

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

2015-01-01

98

Genomic Evolution of Saccharomyces cerevisiae under Chinese Rice Wine Fermentation  

PubMed Central

Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. PMID:25212861

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

2014-01-01

99

Engineered production of fungal anticancer cyclooligomer depsipeptides in Saccharomyces cerevisiae.  

PubMed

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

100

Physiological adaptations of Saccharomyces cerevisiae evolved for improved butanol tolerance  

PubMed Central

Background Butanol is a chemical with potential uses as biofuel and solvent, which can be produced by microbial fermentation. However, the end product toxicity is one of the main obstacles for developing the production process irrespective of the choice of production organism. The long-term goal of the present project is to produce 2-butanol in Saccharomyces cerevisiae. Therefore, unraveling the toxicity mechanisms of solvents such as butanol and understanding the mechanisms by which tolerant strains of S. cerevisiae adapt to them would be an important contribution to the development of a bio-based butanol production process. Results A butanol tolerant S. cerevisiae was achieved through a series of sequential batch cultures with gradual increase of 2-butanol concentration. The final mutant (JBA-mut) tolerates all different alcohols tested at higher concentrations compared to the wild type (JBA-wt). Proteomics analysis of the two strains grown under mild butanol-stress revealed 46 proteins changing their expression by more than 1.5-fold in JBA-mut, 34 of which were upregulated. Strikingly, 21 out of the 34 upregulated proteins were predicted constituents of mitochondria. Among the non-mitochondrial up-regulated proteins, the minor isoform of Glycerol-3-phosphatase (Gpp2) was the most notable, since it was the only tested protein whose overexpression was found to confer butanol tolerance. Conclusion The study demonstrates several differences between the butanol tolerant mutant and the wild type. Upregulation of proteins involved in the mitochondrial ATP synthesizing machinery constituents and glycerol biosynthesis seem to be beneficial for a successful adaptation of yeast cells to butanol stress. PMID:23855998

2013-01-01

101

High level secretion of cellobiohydrolases by Saccharomyces cerevisiae  

PubMed Central

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. PMID:21910902

2011-01-01

102

Role of social wasps in Saccharomyces cerevisiae ecology and evolution  

PubMed Central

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

2012-01-01

103

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

EPA Science Inventory

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...

104

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

Microsoft Academic Search

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

M. J. Herrgard; Baek-Seok Lee; Vasiliy Portnoy; Bernhard Ø

2006-01-01

105

Control of lactate production by Saccharomyces cerevisiae expressing a bacterial LDH gene  

Microsoft Academic Search

Potential industrial applications for lactate, such as the production of chemicals, has led to interest in producing this organic acid by metabolically engineered yeast such as Saccharomyces cerevisiae. Such microorganisms are more acid tolerant than lactic acid bacteria. This paper deals with the potential of the genetically modified S. cerevisiae strain K1-LDH (the lactate dehydrogenase gene of Lactobacillus plantarum has

S Dequin; J. M Sablayrolles

2003-01-01

106

Mixing of vineyard and oak-tree ecotypes of Saccharomyces cerevisiae in North American vineyards  

E-print Network

Mixing of vineyard and oak-tree ecotypes of Saccharomyces cerevisiae in North American vineyards are genetically differentiated from strains isolated from oak- tree bark, exudate and associated soil in North groups. We examined S. cerevisiae strains isolated from grapes and oak trees within three North American

Fay, Justin

107

Saccharomyces Genome Database (SGD) provides tools to identify and analyze sequences from Saccharomyces cerevisiae and related sequences from other organisms  

Microsoft Academic Search

The Saccharomyces Genome Database (SGD; http:\\/\\/ www.yeastgenome.org\\/), a scientific database of the molecular biology and genetics of the yeast Saccharomyces cerevisiae, has recently developed several new resources that allow the comparison and integration of information on a genome-wide scale, enabling the user not only to find detailed information about individual genes, but also to make connections across groups of genes

Karen R. Christie; Shuai Weng; Rama Balakrishnan; Maria C. Costanzo; Kara Dolinski; Selina S. Dwight; Stacia R. Engel; Becket Feierbach; Dianna G. Fisk; Jodi E. Hirschman; Eurie L. Hong; Laurie Issel-tarver; Robert S. Nash; Anand Sethuraman; Barry Starr; Chandra L. Theesfeld; Rey Andrada; Gail Binkley; Qing Dong; Mark Schroeder; David Botstein; J. Michael Cherry

2004-01-01

108

Construction of a flocculent Saccharomyces cerevisiae strain secreting high levels of Aspergillus niger ?-galactosidase  

Microsoft Academic Search

A flocculent Saccharomyces cerevisiae strain secreting Aspergillus niger ?-galactosidase activity was constructed by transforming S. cerevisiae NCYC869-A3 strain with plasmid pVK1.1 harboring the A. niger ?-ga- lactosidase gene, lacA, under the control of the ADH1 promoter and terminator. Compared to other recombinant S. cerevisiae strains, this recombinant yeast has higher levels of extracellular ?-galactosidase activity. In shake- flask cultures, the

J. A. Teixeira; M. Penttilä; N. Lima

2002-01-01

109

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

PubMed

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

110

Raw starch conversion by Saccharomyces cerevisiae expressing Aspergillus tubingensis amylases  

PubMed Central

Background Starch is one of the most abundant organic polysaccharides available for the production of bio-ethanol as an alternative transport fuel. Cost-effective utilisation of starch requires consolidated bioprocessing (CBP) where a single microorganism can produce the enzymes required for hydrolysis of starch, and also convert the glucose monomers to ethanol. Results The Aspergillus tubingensis T8.4 ?-amylase (amyA) and glucoamylase (glaA) genes were cloned and expressed in the laboratory strain Saccharomyces cerevisiae Y294 and the semi-industrial strain, S. cerevisiae Mnu?1. The recombinant AmyA and GlaA displayed protein sizes of 110–150 kDa and 90 kDa, respectively, suggesting significant glycosylation in S. cerevisiae. The Mnu?1[AmyA-GlaA] and Y294[AmyA-GlaA] strains were able to utilise 20 g l-1 raw corn starch as sole carbohydrate source, with ethanol titers of 9.03 and 6.67 g l-1 (0.038 and 0.028 g l-1 h-1), respectively, after 10 days. With a substrate load of 200 g l-1 raw corn starch, Mnu?1[AmyA-GlaA] yielded 70.07 g l-1 ethanol (0.58 g l-1 h-1) after 120 h of fermentation, whereas Y294[AmyA-GlaA] was less efficient at 43.33 g l-1 ethanol (0.36 g l-1 h-1). Conclusions In a semi-industrial amylolytic S. cerevisiae strain expressing the A. tubingensis ?-amylase and glucoamylase genes, 200 g l-1 raw starch was completely hydrolysed (saccharified) in 120 hours with 74% converted to released sugars plus fermentation products and the remainder presumably to biomass. The single-step conversion of raw starch represents significant progress towards the realisation of CBP without the need for any heat pretreatment. Furthermore, the amylases were produced and secreted by the host strain, thus circumventing the need for exogenous amylases. PMID:24286270

2013-01-01

111

The plasma membrane of Saccharomyces cerevisiae: structure, function, and biogenesis.  

PubMed Central

The composition of phospholipids, sphingolipids, and sterols in the plasma membrane has a strong influence on the activity of the proteins associated or embedded in the lipid bilayer. Since most lipid-synthesizing enzymes in Saccharomyces cerevisiae are located in intracellular organelles, an extensive flux of lipids from these organelles to the plasma membrane is required. Although the pathway of protein traffic to the plasma membrane is similar to that of most of the lipids, the bulk flow of lipids is separate from vesicle-mediated protein transport. Recent advances in the analysis of membrane budding and membrane fusion indicate that the mechanisms of protein transport from the endoplasmic reticulum to the Golgi and from the Golgi to plasma membrane are similar. The majority of plasma membrane proteins transport solutes across the membrane. A number of ATP-dependent export systems have been detected that couple the hydrolysis of ATP to transport of molecules out of the cell. The hydrolysis of ATP by the plasma membrane H(+)-ATPase generates a proton motive force which is used to drive secondary transport processes. In S. cerevisiae, many substrates are transported by more than one system. Transport of monosaccharide is catalyzed by uniport systems, while transport of disaccharides, amino acids, and nucleosides is mediated by proton symport systems. Transport activity can be regulated at the level of transcription, e.g., induction and (catabolite) repression, but transport proteins can also be affected posttranslationally by a process termed catabolite inactivation. Catabolite inactivation is triggered by the addition of fermentable sugars, intracellular acidification, stress conditions, and/or nitrogen starvation. Phosphorylation and/or ubiquitination of the transport proteins has been proposed as an initial step in the controlled inactivation and degradation of the target enzyme. The use of artificial membranes, like secretory vesicles and plasma membranes fused with proteoliposomes, as model systems for studies on the mechanism and regulation of transport is evaluated. PMID:7603412

van der Rest, M E; Kamminga, A H; Nakano, A; Anraku, Y; Poolman, B; Konings, W N

1995-01-01

112

Filament formation in Saccharomyces cerevisiae--a review.  

PubMed

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

113

Identification and Characterization of Phenylpyruvate Decarboxylase Genes in Saccharomyces cerevisiae  

PubMed Central

Catabolism of amino acids via the Ehrlich pathway involves transamination to the corresponding ?-keto acids, followed by decarboxylation to an aldehyde and then reduction to an alcohol. Alternatively, the aldehyde may be oxidized to an acid. This pathway is functional in Saccharomyces cerevisiae, since during growth in glucose-limited chemostat cultures with phenylalanine as the sole nitrogen source, phenylethanol and phenylacetate were produced in quantities that accounted for all of the phenylalanine consumed. Our objective was to identify the structural gene(s) required for the decarboxylation of phenylpyruvate to phenylacetaldehyde, the first specific step in the Ehrlich pathway. S. cerevisiae possesses five candidate genes with sequence similarity to genes encoding thiamine diphosphate-dependent decarboxylases that could encode this activity: YDR380w/ARO10, YDL080C/THI3, PDC1, PDC5, and PDC6. Phenylpyruvate decarboxylase activity was present in cultures grown with phenylalanine as the sole nitrogen source but was absent from ammonia-grown cultures. Furthermore, the transcript level of one candidate gene (ARO10) increased 30-fold when phenylalanine replaced ammonia as the sole nitrogen source. Analyses of phenylalanine catabolite production and phenylpyruvate decarboxylase enzyme assays indicated that ARO10 was sufficient to encode phenylpyruvate decarboxylase activity in the absence of the four other candidate genes. There was also an alternative activity with a higher capacity but lower affinity for phenylpyruvate. The candidate gene THI3 did not itself encode an active phenylpyruvate decarboxylase but was required along with one or more pyruvate decarboxylase genes (PDC1, PDC5, and PDC6) for the alternative activity. The Km and Vmax values of the two activities differed, showing that Aro10p is the physiologically relevant phenylpyruvate decarboxylase in wild-type cells. Modifications to this gene could therefore be important for metabolic engineering of the Ehrlich pathway. PMID:12902239

Vuralhan, Zeynep; Morais, Marcos A.; Tai, Siew-Leng; Piper, Matthew D. W.; Pronk, Jack T.

2003-01-01

114

Increased inactivation of Saccharomyces cerevisiae by protraction of UV irradiation.  

PubMed Central

The principle of equi-effectivity of the product of intensity and exposure time (principle of Bunsen-Roscoe) of UV irradiation has been assumed to be valid for the inactivation of microorganisms in general. Earlier studies claimed higher survival of Escherichia coli B/r with fractionated irradiation compared with single-exposure survival. However, data on the inactivation effect of protraction of UV irradiation are not available. By means of a specially designed UV irradiation apparatus which secured absolute UV dose measurements throughout the experiments, the effects of variation of UV irradiation intensities (253.7 nm) and exposure times were tested on the inactivation of a bacterial virus (Staphylococcus aureus phage A994), a vegetative bacterial strain (E. coli ATCC 25922), and bacterial spores (Bacillus subtilis ATCC 6633) as well as three haploid laboratory strains (RC43a, YNN281, and YNN282) and two diploid strains (commercial bakery yeast strain and laboratory strain YNN281 x YNN282) or yeast (Saccharomyces cerevisiae) and spores of the latter diploid yeast strain. Each test organism was exposed to three UV intensities (0.02, 0.2, and 2 W/m2), with corresponding exposure times resulting in three dose levels for each intensity. Differences in inactivation rates were tested by analyses of variance and Newman-Keuls tests. Virus and bacteria showed no differences in inactivation rates by variation of intensities and exposure times within selected UV doses; hence, the principle of Bunsen-Roscoe could not be rejected for these strains. However, in the eukaryotic test strains of S. cerevisiae longer exposure times with lower intensities led to enhanced inactivation in both haploid and diploid strains, with a more pronounced effect in the diploid yeast strains, whereas in yeast spores in this dose rate effect could not be observed. PMID:8787396

Sommer, R; Haider, T; Cabaj, A; Heidenreich, E; Kundi, M

1996-01-01

115

Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae.  

PubMed

Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment. PMID:23614011

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

2013-01-01

116

Calcium Dependence of Eugenol Tolerance and Toxicity in Saccharomyces cerevisiae  

PubMed Central

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

117

MAP kinase pathways in the yeast Saccharomyces cerevisiae  

NASA Technical Reports Server (NTRS)

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

118

Dynamic regulation of mitochondrial respiratory chain efficiency in Saccharomyces cerevisiae.  

PubMed

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

119

Mating-Type Genes and MAT Switching in Saccharomyces cerevisiae  

PubMed Central

Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MAT?. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MAT?1, and MAT?2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HML? and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break. PMID:22555442

Haber, James E.

2012-01-01

120

The Network Architecture of the Saccharomyces cerevisiae Genome  

PubMed Central

We propose a network-based approach for surmising the spatial organization of genomes from high-throughput interaction data. Our strategy is based on methods for inferring architectural features of networks. Specifically, we employ a community detection algorithm to partition networks of genomic interactions. These community partitions represent an intuitive interpretation of genomic organization from interaction data. Furthermore, they are able to recapitulate known aspects of the spatial organization of the Saccharomyces cerevisiae genome, such as the rosette conformation of the genome, the clustering of centromeres, as well as tRNAs, and telomeres. We also demonstrate that simple architectural features of genomic interaction networks, such as cliques, can give meaningful insight into the functional role of the spatial organization of the genome. We show that there is a correlation between inter-chromosomal clique size and replication timing, as well as cohesin enrichment. Together, our network-based approach represents an effective and intuitive framework for interpreting high-throughput genomic interaction data. Importantly, there is a great potential for this strategy, given the rich literature and extensive set of existing tools in the field of network analysis. PMID:24349163

Hoang, Stephen A.; Bekiranov, Stefan

2013-01-01

121

Oxalurate induction of multiple URA3 transcripts in Saccharomyces cerevisiae.  

PubMed Central

The URA3 gene from Saccharomyces cerevisiae is localized on a 1.1-kilobase (kb) DNA fragment. By using this fragment as a hybridization probe, we found that oxalurate, a gratuitous inducer of the allantoin degradative system, also serves to induce URA3 specific RNA. This response is restricted to oxalurate; other conditions which bring about high-level synthesis of the allantoin degradative enzymes did not produce the effect. Two classes of RNA (1.0 and 1.5 kb) were found to be oxalurate induced. Both classes are encoded by the URA3 gene, overlap, and probably do not significantly differ at their 5' termini. Northern blot mapping of the transcripts indicated that the 1.5-kb transcript was likely encoded by sequences extending up to 0.5 kb downstream from the 3' terminus of the 1.0-kb transcript. Analysis of the endpoints of the major 1.0-kb URA3 transcript by S1 nuclease mapping revealed the existence of two 5' termini, separated by 5 to 10 nucleotides, and seven 3' termini, separated by 5 to 20 nucleotides each, over a range of about 70 bases. Images PMID:6140626

Buckholz, R G; Cooper, T G

1983-01-01

122

Symmetric cell division in pseudohyphae of the yeast Saccharomyces cerevisiae.  

PubMed Central

Laboratory strains of Saccharomyces cerevisiae are dimorphic; in response to nitrogen starvation they switch from a yeast form (YF) to a filamentous pseudohyphal (PH) form. Time-lapse video microscopy of dividing cells reveals that YF and PH cells differ in their cell cycles and budding polarity. The YF cell cycle is controlled at the G1/S transition by the cell-size checkpoint Start. YF cells divide asymmetrically, producing small daughters from full-sized mothers. As a result, mothers and daughters bud asynchronously. Mothers bud immediately but daughters grow in G1 until they achieve a critical cell size. By contrast, PH cells divide symmetrically, restricting mitosis until the bud grows to the size of the mother. Thus, mother and daughter bud synchronously in the next cycle, without a G1 delay before Start. YF and PH cells also exhibit distinct bud-site selection patterns. YF cells are bipolar, producing their second and subsequent buds at either pole. PH cells are unipolar, producing their second and subsequent buds only from the end opposite the junction with their mother. We propose that in PH cells a G2 cell-size checkpoint delays mitosis until bud size reaches that of the mother cell. We conclude that yeast and PH forms are distinct cell types each with a unique cell cycle, budding pattern, and cell shape. Images PMID:7841518

Kron, S J; Styles, C A; Fink, G R

1994-01-01

123

Adaptive on-line model for aerobic Saccharomyces cerevisiae fermentation.  

PubMed

In order to study and control fermentation processes, indirect on-tine measurements and mathematical models can be used. In this article we present a mathematical on-line model for fermentation processes. The model is based on atom and partial mass balances as well as on equations describing the acid-base system. The model is brought into an adaptive form by including transport equations for mass transfer and unstructured expressions for the fermentation kinetics. The state of the process, i.e., the concentrations of biomass, substrate, and products, can be estimated on-line using the balance part of the model completed with measurement equations for the input and output flows of the process. Adaptivity is realized by means of on-line estimation of parameters in the transport and kinetic expressions using recursive regression analysis. These expressions can thus be used in the model as valid equations enabling prediction of the process. This makes model-based automation of the process and testing of the validity of the measurement variables possible. The model and the on-line principles are applied to a 3.5-L laboratory tormentor in which Saccharomyces cerevisiae is cultivated. The experimental results show that the model-based estimation of the state and the predictions of the process correlate closely with high-performance liquid chromatography (HPLC) analyses. (c) 1995 John Wiley & Sons, Inc. PMID:18623532

von Schalien, R; Fagervik, K; Saxén, B; Ringbom, K; Rydström, M

1995-12-20

124

Identification of Genes Affecting Vacuole Membrane Fragmentation in Saccharomyces cerevisiae  

PubMed Central

The equilibrium of membrane fusion and fission influences the volume and copy number of organelles. Fusion of yeast vacuoles has been well characterized but their fission and the mechanisms determining vacuole size and abundance remain poorly understood. We therefore attempted to systematically characterize factors necessary for vacuole fission. Here, we present results of an in vivo screening for deficiencies in vacuolar fragmentation activity of an ordered collection deletion mutants, representing 4881 non-essential genes of the yeast Saccharomyces cerevisiae. The screen identified 133 mutants with strong defects in vacuole fragmentation. These comprise numerous known fragmentation factors, such as the Fab1p complex, Tor1p, Sit4p and the V-ATPase, thus validating the approach. The screen identified many novel factors promoting vacuole fragmentation. Among those are 22 open reading frames of unknown function and three conspicuous clusters of proteins with known function. The clusters concern the ESCRT machinery, adaptins, and lipases, which influence the production of diacylglycerol and phosphatidic acid. A common feature of these factors of known function is their capacity to change membrane curvature, suggesting that they might promote vacuole fragmentation via this property. PMID:23383298

Michaillat, Lydie; Mayer, Andreas

2013-01-01

125

The diphthamide modification pathway from Saccharomyces cerevisiae - revisited.  

PubMed

Diphthamide is a conserved modification in archaeal and eukaryal translation elongation factor 2 (EF2). Its name refers to the target function for diphtheria toxin, the disease-causing agent that, through ADP ribosylation of diphthamide, causes irreversible inactivation of EF2 and cell death. Although this clearly emphasizes a pathobiological role for diphthamide, its physiological function is unclear, and precisely why cells need EF2 to contain diphthamide is hardly understood. Nonetheless, the conservation of diphthamide biosynthesis together with syndromes (i.e. ribosomal frame-shifting, embryonic lethality, neurodegeneration and cancer) typical of mutant cells that cannot make it strongly suggests that diphthamide-modified EF2 occupies an important and translation-related role in cell proliferation and development. Whether this is structural and/or regulatory remains to be seen. However, recent progress in dissecting the diphthamide gene network (DPH1-DPH7) from the budding yeast Saccharomyces cerevisiae has significantly advanced our understanding of the mechanisms required to initiate and complete diphthamide synthesis on EF2. Here, we review recent developments in the field that not only have provided novel, previously overlooked and unexpected insights into the pathway and the biochemical players required for diphthamide synthesis but also are likely to foster innovative studies into the potential regulation of diphthamide, and importantly, its ill-defined biological role. PMID:25352115

Schaffrath, Raffael; Abdel-Fattah, Wael; Klassen, Roland; Stark, Michael J R

2014-12-01

126

Transcriptional regulatory network shapes the genome structure of Saccharomyces cerevisiae  

PubMed Central

Among cellular processes gene transcription is central. More and more evidence is mounting that transcription is tightly connected with the spatial organization of the chromosomes. Spatial proximity of genes sharing transcriptional machinery is one of the consequences of this organization. Motivated by information on the physical relationship among genes identified via chromosomal conformation capture methods, we complement the spatial organization with the idea that genes under similar transcription factor control, but possible scattered throughout the genome, might be in physically proximity to facilitate the access of their commonly used transcription factors. Unlike the transcription factory model, “interacting” genes in our “Gene Proximity Model” are not necessarily immediate physical neighbors but are in spatial proximity. Considering the stochastic nature of TF-promoter binding, this local condensation mechanism could serve as a tie to recruit co-regulated genes to guarantee the swiftness of biological reactions. We tested this idea with a simple eukaryotic organism, Saccharomyces cerevisiae. Chromosomal interaction patterns and folding behavior generated by our model re-construct those obtained from experiments. We show that the transcriptional regulatory network has a close linkage with the genome organization in budding yeast, which is fundamental and instrumental to later studies on other more complex eukaryotes. PMID:23674068

Li, Songling; Heermann, Dieter W.

2013-01-01

127

Comparative Genomics of Saccharomyces cerevisiae Natural Isolates for Bioenergy Production  

PubMed Central

Lignocellulosic plant material is a viable source of biomass to produce alternative energy including ethanol and other biofuels. However, several factors—including toxic byproducts from biomass pretreatment and poor fermentation of xylose and other pentose sugars—currently limit the efficiency of microbial biofuel production. To begin to understand the genetic basis of desirable traits, we characterized three strains of Saccharomyces cerevisiae with robust growth in a pretreated lignocellulosic hydrolysate or tolerance to stress conditions relevant to industrial biofuel production, through genome and transcriptome sequencing analysis. All stress resistant strains were highly mosaic, suggesting that genetic admixture may contribute to novel allele combinations underlying these phenotypes. Strain-specific gene sets not found in the lab strain were functionally linked to the tolerances of particular strains. Furthermore, genes with signatures of evolutionary selection were enriched for functional categories important for stress resistance and included stress-responsive signaling factors. Comparison of the strains’ transcriptomic responses to heat and ethanol treatment—two stresses relevant to industrial bioethanol production—pointed to physiological processes that were related to particular stress resistance profiles. Many of the genotype-by-environment expression responses occurred at targets of transcription factors with signatures of positive selection, suggesting that these strains have undergone positive selection for stress tolerance. Our results generate new insights into potential mechanisms of tolerance to stresses relevant to biofuel production, including ethanol and heat, present a backdrop for further engineering, and provide glimpses into the natural variation of stress tolerance in wild yeast strains. PMID:25364804

Wohlbach, Dana J.; Rovinskiy, Nikolay; Lewis, Jeffrey A.; Sardi, Maria; Schackwitz, Wendy S.; Martin, Joel A.; Deshpande, Shweta; Daum, Christopher G.; Lipzen, Anna; Sato, Trey K.; Gasch, Audrey P.

2014-01-01

128

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall  

PubMed Central

The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of ?1,3- and ?1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, ?1,3- and ?1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. PMID:23135325

Orlean, Peter

2012-01-01

129

[Improving ergosterol production from molasses by Saccharomyces cerevisiae].  

PubMed

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

130

Instability of CAG and CTG trinucleotide repeats in Saccharomyces cerevisiae.  

PubMed Central

A quantitative genetic assay was developed to monitor alterations in tract lengths of trinucleotide repeat sequences in Saccharomyces cerevisiae. Insertion of (CAG)50 or (CTG)50 repeats into a promoter that drives expression of the reporter gene ADE8 results in loss of expression and white colony color. Contractions within the trinucleotide sequences to repeat lengths of 8 to 38 restore functional expression of the reporter, leading to red colony color. Reporter constructs including (CAG)50 or (CTG)50 repeat sequences were integrated into the yeast genome, and the rate of red colony formation was measured. Both orientations yielded high rates of instability (4 x 10(-4) to 18 x 10(-4) per cell generation). Instability depended on repeat sequences, as a control harboring a randomized (C,A,G)50 sequence was at least 100-fold more stable. PCR analysis of the trinucleotide repeat region indicated an excellent correlation between change in color phenotype and reduction in length of the repeat tracts. No preferential product sizes were observed. Strains containing disruptions of the mismatch repair gene MSH2, MSH3, or PMS1 or the recombination gene RAD52 showed little or no difference in rates of instability or distributions of products, suggesting that neither mismatch repair nor recombination plays an important role in large contractions of trinucleotide repeats in yeast. PMID:9154837

Miret, J J; Pessoa-Brandão, L; Lahue, R S

1997-01-01

131

Passage through stationary phase advances replicative aging in Saccharomyces cerevisiae  

PubMed Central

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

132

Regulation of protein synthesis during early limitation of Saccharomyces cerevisiae.  

PubMed Central

Arsenate, a competitive inhibitor with phosphate in phosphorylation reactions, has been used to lower adenine and guanine nucleotide levels in Saccharomyces cerevisiae to study nucleotide effects on protein synthesis. By measuring polysome levels, we have shown that initiation of protein synthesis is much more sensitive than elongation or termination to inhibition when the ATP/ADP, GTP/GDP ratios are low. When the arsenate-phosphate molar ratio was 0.27, protein synthesis was inhibited by about 85% and the kinetics of polysome decay was similar to that observed with the initiation inhibitor, verrucarin-76, or with the protein synthesis initiation mutant, ts187, at the restrictive temperature. With this level of arsenate, the adenylate energy charge dropped from 0.9 to 0.7 and the ATP/ADP and GTP/GDP ratios dropped from 6 to 2. The observed correlations between nucleotide ratio changes and inhibition of protein synthesis suggest that the former may be a control signal for the latter. The significance of these in vivo correlations will have to be tested with an in vitro protein synthesizing system. Higher arsenate levels resulted in even lower ATP/ADP, GTP/GDP ratios and in a slower decay of polysomes, implying that, eventually, elongation (in addition to initiation) was being inhibited. PMID:374362

Swedes, J S; Dial, M E; McLaughlin, C S

1979-01-01

133

NH2-terminal acetylation of ribosomal proteins of Saccharomyces cerevisiae.  

PubMed

Using a mutant of Saccharomyces cerevisiae defective in the NAT1 gene, that encodes one of the NH2-terminal acetyltransferases, we have identified 14 ribosomal proteins whose electrophoretic mobility at pH 5.0 suggests they carry an additional charge, presumably due to the lack of NH2-terminal acetylation. At least 30 other ribosomal proteins from the mutant are electrophoretically normal. Attempted NH2-terminal analysis of most of the presumed acetylated proteins from wild type cells indicated that all were blocked. NH2-terminal analysis of the same proteins from the nat1 mutant strain yielded unique sequences. Each one carries an NH2-terminal serine. We conclude that these are normally acetylated due to the presence of the NAT1 gene product. It seems surprising that cells whose ribosomes have been altered to this degree grow rather well and synthesize the same spectrum of proteins as do wild type cells (Mullen, J. R., Kayne, P. S., Moerschell, R. P., Tsunasawa, S. Gribskov, M., Sherman, F., and Sternglanz, R. (1989) EMBO J. 8, 2067-2075). Finally, this analysis has provided the first sequence information available for several of the acetylated ribosomal proteins and for one non-acetylated ribosomal protein, which is clearly the product of the MFT1 gene (Garrett, J. M., Singh, K. K., Vonder Haar, R. A., and Emr. S. D. (1991) Mol. Gen. Gen. 225, 483-491). PMID:1544921

Takakura, H; Tsunasawa, S; Miyagi, M; Warner, J R

1992-03-15

134

Killed Saccharomyces cerevisiae protects against lethal challenge of Cryptococcus grubii.  

PubMed

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

135

Metabolic Engineering of Saccharomyces cerevisiae for Caffeine and Theobromine Production  

PubMed Central

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

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

2014-01-01

136

Post-Transcriptional Regulation of Iron Homeostasis in Saccharomyces cerevisiae  

PubMed Central

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. PMID:23903042

Martínez-Pastor, María Teresa; de Llanos, Rosa; Romero, Antonia María; Puig, Sergi

2013-01-01

137

Reversal of PCNA Ubiquitylation by Ubp10 in Saccharomyces cerevisiae  

PubMed Central

Regulation of PCNA ubiquitylation plays a key role in the tolerance to DNA damage in eukaryotes. Although the evolutionary conserved mechanism of PCNA ubiquitylation is well understood, the deubiquitylation of ubPCNA remains poorly characterized. Here, we show that the histone H2BK123 ubiquitin protease Ubp10 also deubiquitylates ubPCNA in Saccharomyces cerevisiae. Our results sustain that Ubp10-dependent deubiquitylation of the sliding clamp PCNA normally takes place during S phase, likely in response to the simple presence of ubPCNA. In agreement with this, we show that Ubp10 forms a complex with PCNA in vivo. Interestingly, we also show that deletion of UBP10 alters in different ways the interaction of PCNA with DNA polymerase ?–associated protein Rev1 and with accessory subunit Rev7. While deletion of UBP10 enhances PCNA–Rev1 interaction, it decreases significantly Rev7 binding to the sliding clamp. Finally, we report that Ubp10 counteracts Rad18 E3-ubiquitin ligase activity on PCNA at lysine 164 in such a manner that deregulation of Ubp10 expression causes tolerance impairment and MMS hypersensitivity. PMID:22829782

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

2012-01-01

138

Nitrogen catabolite repression of asparaginase II in Saccharomyces cerevisiae.  

PubMed Central

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 source of nitrogen. (ii) In a yeast strain carrying the gdhA mutation, asparaginase II was synthesized at fully derepressed levels when 10 mM ammonium sulfate was the source of nitrogen. When amino acids (10 mM) served as the nitrogen source, asparaginase II synthesis was strongly repressed. (iii) In a strain carrying the gdhCR mutation, the synthesis of asparaginase II was partially (30 to 40%) derepressed when either 10 mM ammonium sulfate or amino acids were present in the medium. (iv) In a yeast strain containing both gdhA and gdhCR mutations, asparaginase II synthesis was fully derepressed when 10 mM ammonium sulfate was the nitrogen source and partially derepressed when 10 mM amino acids were present. (v) Yeast strains carrying the gdhCS mutation were indistinguishable from the wild-type strain with respect to asparaginase II synthesis. PMID:6995441

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

1980-01-01

139

Engineering chimeric thermostable GH7 cellobiohydrolases in Saccharomyces cerevisiae.  

PubMed

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

140

Characterization of a mitochondrial inorganic pyrophosphatase in Saccharomyces cerevisiae.  

PubMed

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

141

Regulation of the Saccharomyces cerevisiae DNA repair gene RAD16.  

PubMed Central

The RAD16 gene product has been shown to be essential for the repair of the silenced mating type loci [Bang et al. (1992) Nucleic Acids Res. 20, 3925-3931]. More recently we demonstrated that the RAD16 and RAD7 proteins are also required for repair of non-transcribed strands of active genes in Saccharomyces cerevisiae [Waters et al. (1993) Mol. Gen. Genet. 239, 28-32]. We have studied the regulation of the RAD16 gene and found that the RAD16 transcript levels increased up to 7-fold upon UV irradiation. Heat shock at 42 degrees C also results in elevated levels of RAD16 mRNA. In sporulating MAT alpha/MATa diploid cells RAD16 mRNA is also induced. The basal level of the RAD16 transcript is constant during the mitotic cell cycle. G1-arrested cells show normal induction of RAD16 mRNA upon UV irradiation demonstrating that the induction is not a secondary consequence of G2 cell cycle arrest following UV irradiation. However, in cells arrested in G1 the induction of RAD16 mRNA after UV irradiation is not followed by a rapid decline as occurs in normal growing cells suggesting that the down regulation of RAD16 transcription is dependent on progression into the cell cycle. Images PMID:7784171

Bang, D D; Timmermans, V; Verhage, R; Zeeman, A M; van de Putte, P; Brouwer, J

1995-01-01

142

Protein phosphatase type 1 regulates ion homeostasis in Saccharomyces cerevisiae.  

PubMed Central

Protein phosphatase type 1 (PP1) is encoded by the essential gene GLC7 in Saccharomyces cerevisiae. glc7-109 (K259A, R260A) has a dominant, hyperglycogen defect and a recessive, ion and drug sensitivity. Surprisingly, the hyperglycogen phenotype is partially retained in null mutants of GAC1, GIP2, and PIG1, which encode potential glycogen-targeting subunits of Glc7. The R260A substitution in GLC7 is responsible for the dominant and recessive traits of glc7-109. Another mutation at this residue, glc7-R260P, confers only salt sensitivity, indicating that the glycogen and salt traits of glc7-109 are due to defects in distinct physiological pathways. The glc7-109 mutant is sensitive to cations, aminoglycosides, and alkaline pH and exhibits increased rates of l-leucine and 3,3'-dihexyloxacarbocyanine iodide uptake, but it is resistant to molar concentrations of sorbitol or KCl, indicating that it has normal osmoregulation. KCl suppresses the ion and drug sensitivities of the glc7-109 mutant. The CsCl sensitivity of this mutant is suppressed by recessive mutations in PMA1, which encodes the essential plasma membrane H(+)ATPase. Together, these results indicate that Glc7 regulates ion homeostasis by controlling ion transport and/or plasma membrane potential, a new role for Glc7 in budding yeast. PMID:11973298

Williams-Hart, Tara; Wu, Xiaolin; Tatchell, Kelly

2002-01-01

143

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

PubMed

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

144

Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.  

PubMed

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

145

Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation  

PubMed Central

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

2013-01-01

146

Nutritional and environmental factors in ethanol fermentation by Saccharomyces cerevisiae  

SciTech Connect

Using Saccharomyces cerevisiae as a model system, a basic study of the nutritional and environmental factors in ethanol fermentation was carried out to provide fundamental and practical bases for design of fermentation media and culture conditions. The requirements for all active medium components need to be determined in order to establish balanced media, which are important to reduce raw materials costs and to minimize inhibition from buildup of excess feed components in recycle processes with selective ethanol removal. Pulse injection of nutrients into continuous cultures was an effective method for screening active nutrients. In a systematic sensitivity analysis the effect of feed concentration of these individual nutrients was then determined and allowed formulation of media optimal with respect to the major fermentation parameters. Biotin, pantothenate, myo-inositol, potassium and phosphates appeared to stimulate growth preferentially to ethanol production. In contrast, thiamine and pyridoxine appeared to enhance specific ethanol productivity. The effect of ammonium sulfate depended on concentration. A conceptual model was proposed to relate the effects of these nutrients to biochemical pathways and functions. With these data and model the minimum cost combination of raw materials to achieve a medium of well defined components can be determined with a linear program. This computer program shows that many growth factors and minerals can be added to media more economically as pure components than as fractions of complex factors. 225 references, 61 figures, 54 tables.

Wong, H.; Wilke, C.R.; Blanch, H.W.

1983-05-01

147

Nutritional and environmental factors in ethanol fermentation by Saccharomyces cerevisiae  

SciTech Connect

Using Saccharomyces cerevisiae as a model system, a basic study of the nutritional and environmental factors in ethanol fermentation was carried out to provide fundamental and practical bases for design of fermentation media and culture conditions. The requirements for all active medium components need to be determined in order to establish balanced media, which are important to reduce raw materials costs and to minimize inhibition from build-up of excess feed components in recycle processes with selective ethanol removal. The effect of feed concentration of individual nutrients was determined and allowed formulation of media optimal with respect to the major fermentation parameters. Biotin, pantothenate, myoinositol, potassium, and phosphates appeared to stimulate growth preferentially to ethanol production. Thiamine and pyridoxine appeared to have the opposite effect. A conceptual model was proposed to relate the effects of these nutrients to biochemical pathways and functions. The minimum cost combination of raw materials to achieve a medium of well defined components can be determined with a linear program. The effect of dissolved oxygen was studied from essentially zero to 346 mm Hg oxygen tension, showing a continuous decline in specific ethanol productivity with increasing oxygen over this range. Long term continuous cultures resulted in decreased media requirements for growth factors and increased tolerance for ethanol inhibition, most probably through adaptation. An ethanol productivity of 5.6 g/l-hr in continuous culture was achieved with a completely synthetic medium with the improved culture.

Wong, H.

1983-01-01

148

Towards a genome-wide transcriptogram: the Saccharomyces cerevisiae case  

PubMed Central

Analysis of genome-wide expression data poses a challenge to extract relevant information. The usual approaches compare cellular expression levels relative to a pre-established control and genes are clustered based on the correlation of their expression levels. This implies that cluster definitions are dependent on the cellular metabolic state, eventually varying from one experiment to another. We present here a computational method that order genes on a line and clusters genes by the probability that their products interact. Protein–protein association information can be obtained from large data bases as STRING. The genome organization obtained this way is independent from specific experiments, and defines functional modules that are associated with gene ontology terms. The starting point is a gene list and a matrix specifying interactions. Considering the Saccharomyces cerevisiae genome, we projected on the ordering gene expression data, producing plots of transcription levels for two different experiments, whose data are available at Gene Expression Omnibus database. These plots discriminate metabolic cellular states, point to additional conclusions, and may be regarded as the first versions of ‘transcriptograms’. This method is useful for extracting information from cell stimuli/responses experiments, and may be applied with diagnostic purposes to different organisms. PMID:21169199

Rybarczyk-Filho, José Luiz; Castro, Mauro A. A.; Dalmolin, Rodrigo J. S.; Moreira, José C. F.; Brunnet, Leonardo G.; de Almeida, Rita M. C.

2011-01-01

149

TOR and RAS pathways regulate desiccation tolerance in Saccharomyces cerevisiae  

PubMed Central

Tolerance to desiccation in cultures of Saccharomyces cerevisiae is inducible; only one in a million cells from an exponential culture survive desiccation compared with one in five cells in stationary phase. Here we exploit the desiccation sensitivity of exponentially dividing cells to understand the stresses imposed by desiccation and their stress response pathways. We found that induction of desiccation tolerance is cell autonomous and that there is an inverse correlation between desiccation tolerance and growth rate in glucose-, ammonia-, or phosphate-limited continuous cultures. A transient heat shock induces a 5000–fold increase in desiccation tolerance, whereas hyper-ionic, -reductive, -oxidative, or -osmotic stress induced much less. Furthermore, we provide evidence that the Sch9p-regulated branch of the TOR and Ras-cAMP pathway inhibits desiccation tolerance by inhibiting the stress response transcription factors Gis1p, Msn2p, and Msn4p and by activating Sfp1p, a ribosome biogenesis transcription factor. Among 41 mutants defective in ribosome biogenesis, a subset defective in 60S showed a dramatic increase in desiccation tolerance independent of growth rate. We suggest that reduction of a specific intermediate in 60S biogenesis, resulting from conditions such as heat shock and nutrient deprivation, increases desiccation tolerance. PMID:23171550

Welch, Aaron Z.; Gibney, Patrick A.; Botstein, David; Koshland, Douglas E.

2013-01-01

150

CEP3 encodes a centromere protein of Saccharomyces cerevisiae  

PubMed Central

We have designed a screen to identify mutants specifically affecting kinetochore function in the yeast Saccharomyces cerevisiae. The selection procedure was based on the generation of "synthetic acentric" minichromosomes. "Synthetic acentric" minichromosomes contain a centromere locus, but lack centromere activity due to combination of mutations in centromere DNA and in a chromosomal gene (CEP) encoding a putative centromere protein. Ten conditional lethal cep mutants were isolated, seven were found to be alleles of NDC10 (CEP2) encoding the 110-kD protein of yeast kinetochore. Three mutants defined a novel essential gene CEP3. The CEP3 product (Cep3p) is a 71-kD protein with a potential DNA-binding domain (binuclear Zn-cluster). At nonpermissive temperature the cep3 cells arrest with an undivided nucleus and a short mitotic spindle. At permissive temperature the cep3 cells are unable to support segregation of minichromosomes with mutations in the central part of element III of yeast centromere DNA. These minichromosomes, when isolated from cep3 cultures, fail to bind bovine microtubules in vitro. The sum of genetic, cytological and biochemical data lead us to suggest that the Cep3 protein is a DNA-binding component of yeast centromere. Molecular mass and sequence comparison confirm that Cep3p is the p64 component of centromere DNA binding complex Cbf3 (Lechner, 1994). PMID:7876302

1995-01-01

151

Identification of Genes Required for ?2 Repression in Saccharomyces Cerevisiae  

PubMed Central

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 loss of repression. We have screened for other genes required for a-specific gene repression in ? cells. In addition to recovering multiple alleles of previously identified genes required for this process (referred to as ?2 repression), we have identified four other genes, designated ARE1, ARE2, ARE3, and ARE4 (for alpha2 repression). Recessive mutations in the ARE genes cause partial loss of a-specific gene repression and cause pleiotropic phenotypes similar to those resulting from mutations in SSN6, TUP1, or SIN4, suggesting that the ARE genes are general negative regulators. Based on our initial analysis, we propose that two distinct classes of general negative regulators cooperate to bring about full levels of ?2 repression. The sequence of ARE1 revealed that it encodes a CDC28-related protein kinase, identical to UME5, and thus suggests that protein phosphorylation plays a role in ?2 repression. PMID:7635311

Wahi, M.; Johnson, A. D.

1995-01-01

152

Transcriptional Induction by Aromatic Amino Acids in Saccharomyces cerevisiae  

PubMed Central

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, Ismaïl; Vissers, Stéphan; André, Bruno; Urrestarazu, Antonio

1999-01-01

153

Transcriptional induction by aromatic amino acids in Saccharomyces cerevisiae.  

PubMed

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

154

Systematic Identification of Balanced Transposition Polymorphisms in Saccharomyces cerevisiae  

PubMed Central

High-throughput techniques for detecting DNA polymorphisms generally do not identify changes in which the genomic position of a sequence, but not its copy number, varies among individuals. To explore such balanced structural polymorphisms, we used array-based Comparative Genomic Hybridization (aCGH) to conduct a genome-wide screen for single-copy genomic segments that occupy different genomic positions in the standard laboratory strain of Saccharomyces cerevisiae (S90) and a polymorphic wild isolate (Y101) through analysis of six tetrads from a cross of these two strains. Paired-end high-throughput sequencing of Y101 validated four of the predicted rearrangements. The transposed segments contained one to four annotated genes each, yet crosses between S90 and Y101 yielded mostly viable tetrads. The longest segment comprised 13.5 kb near the telomere of chromosome XV in the S288C reference strain and Southern blotting confirmed its predicted location on chromosome IX in Y101. Interestingly, inter-locus crossover events between copies of this segment occurred at a detectable rate. The presence of low-copy repetitive sequences at the junctions of this segment suggests that it may have arisen through ectopic recombination. Our methodology and findings provide a starting point for exploring the origins, phenotypic consequences, and evolutionary fate of this largely unexplored form of genomic polymorphism. PMID:19503594

Faddah, Dina A.; Ganko, Eric W.; McCoach, Caroline; Pickrell, Joseph K.; Hanlon, Sean E.; Mann, Frederick G.; Mieczkowska, Joanna O.; Jones, Corbin D.; Lieb, Jason D.; Vision, Todd J.

2009-01-01

155

Bioflavour production from orange peel hydrolysate using immobilized Saccharomyces cerevisiae.  

PubMed

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

156

Degradation signals for ubiquitin system proteolysis in Saccharomyces cerevisiae.  

PubMed

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

157

Degradation signals for ubiquitin system proteolysis in Saccharomyces cerevisiae.  

PubMed Central

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

1998-01-01

158

Expression of YAP4 in Saccharomyces cerevisiae under osmotic stress.  

PubMed Central

YAP4, a member of the yeast activator protein ( YAP ) gene family, is induced in response to osmotic shock in the yeast Saccharomyces cerevisiae. The null mutant displays mild and moderate growth sensitivity at 0.4 M and 0.8 M NaCl respectively, a fact that led us to analyse YAP4 mRNA levels in the hog1 (high osmolarity glycerol) mutant. The data obtained show a complete abolition of YAP4 gene expression in this mutant, placing YAP4 under the HOG response pathway. YAP4 overexpression not only suppresses the osmosensitivity phenotype of the yap4 mutant but also relieves that of the hog1 mutant. Induction, under the conditions tested so far, requires the presence of the transcription factor Msn2p, but not of Msn4p, as YAP4 mRNA levels are depleted by at least 75% in the msn2 mutant. This result was further substantiated by the fact that full YAP4 induction requires the two more proximal stress response elements. Furthermore we find that GCY1, encoding a putative glycerol dehydrogenase, GPP2, encoding a NAD-dependent glycerol-3-phosphate phosphatase, and DCS2, a homologue to a decapping enzyme, have decreased mRNA levels in the yap4 -deleted strain. Our data point to a possible, as yet not entirely understood, role of the YAP4 in osmotic stress response. PMID:14680476

Nevitt, Tracy; Pereira, Jorge; Azevedo, Dulce; Guerreiro, Paulo; Rodrigues-Pousada, Claudina

2004-01-01

159

Analysis of feedback-resistant anthranilate synthases from Saccharomyces cerevisiae.  

PubMed Central

The initial step of tryptophan biosynthesis is catalyzed by the enzyme anthranilate synthase, which in most microorganisms is subject to feedback inhibition by the end product of the pathway. We have characterized the TRP2 gene from a mutant Saccharomyces cerevisiae strain coding for an anthranilate synthase that is unresponsive to tryptophan. Sequence analysis of this TRP2(Fbr) (feedback-resistant) allele revealed numerous differences from a previously published TRP2 sequence. However, TRP2(Fbr) was found to differ in only one single-point mutation from its own parent wild type, a C-to-T transition resulting in a serine 76-to-leucine 76 amino acid substitution. Therefore, serine 76 is a crucial amino acid for proper regulation of the yeast enzyme. We constructed additional feedback-resistant enzyme forms of the yeast anthranilate synthase by site-directed mutagenesis of the conserved LLES sequence in the TRP2 gene. From analysis of these variants, we propose an extended sequence, LLESX10S, as the regulatory element in tryptophan-responsive anthranilate synthases from prokaryotic and eukaryotic organisms. PMID:8432699

Graf, R; Mehmann, B; Braus, G H

1993-01-01

160

Characterization of Saccharomyces cerevisiae mutants supersensitive to aminoglycoside antibiotics.  

PubMed Central

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 aminoglycoside antibiotic sensitivity). Mutations in all three genes are required for highest antibiotic sensitivity; ags1 ags2 double mutants have intermediate antibiotic sensitivity. AGS1 was mapped 8 centimorgans distal from LEU2 on chromosome III. Analyses of yeast strains transformed with vectors carrying antibiotic resistance genes revealed that G418, gentamicin X2, kanamycin B, lividomycin A, neamine, and paromomycin are inactivated by the Tn903 phosphotransferase and that destomycin A is inactivated by the hygromycin B phosphotransferase. ags strains are improved host strains for vectors carrying the phosphotransferase genes because a wide spectrum of aminoglycoside antibiotics can be used to select for plasmid maintenance. PMID:2989254

Ernst, J F; Chan, R K

1985-01-01

161

Peroxisomal Fatty Acid Uptake Mechanism in Saccharomyces cerevisiae*  

PubMed Central

Peroxisomes play a major role in human cellular lipid metabolism, including fatty acid ?-oxidation. The most frequent peroxisomal disorder is X-linked adrenoleukodystrophy, which is caused by mutations in ABCD1. The biochemical hallmark of X-linked adrenoleukodystrophy is the accumulation of very long chain fatty acids (VLCFAs) due to impaired peroxisomal ?-oxidation. Although this suggests a role of ABCD1 in VLCFA import into peroxisomes, no direct experimental evidence is available to substantiate this. To unravel the mechanism of peroxisomal VLCFA transport, we use Saccharomyces cerevisiae as a model organism. Here we provide evidence that in this organism very long chain acyl-CoA esters are hydrolyzed by the Pxa1p-Pxa2p complex prior to the actual transport of their fatty acid moiety into the peroxisomes with the CoA presumably being released into the cytoplasm. The Pxa1p-Pxa2p complex functionally interacts with the acyl-CoA synthetases Faa2p and/or Fat1p on the inner surface of the peroxisomal membrane for subsequent re-esterification of the VLCFAs. Importantly, the Pxa1p-Pxa2p complex shares this molecular mechanism with HsABCD1 and HsABCD2. PMID:22493507

van Roermund, Carlo W. T.; IJlst, Lodewijk; Majczak, Wiktor; Waterham, Hans R.; Folkerts, Hendrik; Wanders, Ronald J. A.; Hellingwerf, Klaas J.

2012-01-01

162

Dissection of Filamentous Growth by Transposon Mutagenesis in Saccharomyces Cerevisiae  

PubMed Central

Diploid Saccharomyces cerevisiae strains starved for nitrogen undergo a developmental transition from growth as single yeast form (YF) cells to a multicellular form consisting of filaments of pseudohyphal (PH) cells. Filamentous growth is regulated by an evolutionarily conserved signaling pathway that includes the small GTP-binding proteins Ras2p and Cdc42p, the protein kinases Ste20p, Ste11p and Ste7p, and the transcription factor Ste12p. Here, we designed a genetic screen for mutant strains defective for filamentous growth (dfg) to identify novel targets of the filamentation signaling pathway, and we thereby identified 16 different genes, CDC39, STE12, TEC1, WHI3, NAB1, DBR1, CDC55, SRV2, TPM1, SPA2, BNI1, DFG5, DFG9, DFG10, BUD8 and DFG16, mutations that block filamentous growth. Phenotypic analysis of dfg mutant strains genetically dissects filamentous growth into the cellular processes of signal transduction, bud site selection, cell morphogenesis and invasive growth. Epistasis tests between dfg mutant alleles and dominant activated alleles of the RAS2 and STE11 genes, RAS2(Val19) and STE11-4, respectively, identify putative targets for the filamentation signaling pathway. Several of the genes described here have homologues in filamentous fungi, where they also regulate fungal development. PMID:9055077

Mosch, H. U.; Fink, G. R.

1997-01-01

163

In vitro study of the dose effect of Saccharomyces cerevisiae on rumen digestion of a mixed diet  

E-print Network

In vitro study of the dose effect of Saccharomyces cerevisiae on rumen digestion of a mixed diet JP suggested as a mean of stabilizing rumen microbial digestion in animals fed diets rich in starch (RJ Wallace of Saccharomyces cerevisiae (I-1077)* (SC) were tested in Rusitec to study their effects on rumen digestive

Paris-Sud XI, Université de

164

Saccharomyces cerevisiae fungemia, a possible consequence of the treatment of Clostridium difficile colitis with a probioticum.  

PubMed

The yeast Saccharomyces boulardii is a biotherapeutic agent used for the prevention and treatment of several gastrointestinal diseases, such as diarrhoea caused by Clostridium difficile, in addition to the antibiotic therapy. In this study we report a case of Saccharomyces cerevisiae fungemia in a patient with Clostridium difficile-associated diarrhoea (CDAD) treated orally with S. boulardii in association with vancomycin. The identification of the S. cerevisiae was confirmed by molecular technique. Fungemia is a rare, but a serious complication to treatment with probiotics. We believe it is important to remind the clinicians of this risk when prescribing probiotics, especially to immunocompromised patients. PMID:24674691

Santino, I; Alari, A; Bono, S; Teti, E; Marangi, M; Bernardini, A; Magrini, L; Di Somma, S; Teggi, A

2014-01-01

165

Rapid Identification and Enumeration of Saccharomyces cerevisiae Cells in Wine by Real-Time PCR  

PubMed Central

Despite the beneficial role of Saccharomyces cerevisiae in the food industry for food and beverage production, it is able to cause spoilage in wines. We have developed a real-time PCR method to directly detect and quantify this yeast species in wine samples to provide winemakers with a rapid and sensitive method to detect and prevent wine spoilage. Specific primers were designed for S. cerevisiae using the sequence information obtained from a cloned random amplified polymorphic DNA band that differentiated S. cerevisiae from its sibling species Saccharomyces bayanus, Saccharomyces pastorianus, and Saccharomyces paradoxus. The specificity of the primers was demonstrated for typical wine spoilage yeast species. The method was useful for estimating the level of S.?cerevisiae directly in sweet wines and red wines without preenrichment when yeast is present in concentrations as low as 3.8 and 5 CFU per ml. This detection limit is in the same order as that obtained from glucose-peptone-yeast growth medium (GPY). Moreover, it was possible to quantify S. cerevisiae in artificially contaminated samples accurately. Limits for accurate quantification in wine were established, from 3.8 × 105 to 3.8 CFU/ml in sweet wine and from 5 × 106 to 50?CFU/ml in red wine. PMID:16269715

Martorell, P.; Querol, A.; Fernández-Espinar, M. T.

2005-01-01

166

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

PubMed

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

167

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

PubMed Central

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

2011-01-01

168

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

SciTech Connect

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

Uribe, S.; Rangel, P.; Espinola, G.; Aguirre, G. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico))

1990-07-01

169

Statistical optimization of culture media and conditions for production of mannan by Saccharomyces cerevisiae  

Microsoft Academic Search

In view of the increase in Saccharomyces cerevisiae mannan content, the culture medium and condition for S. cerevisiae were optimized in this study. The influence of culture medium ingredients such as carbon and nitrogen sources, inorganic\\u000a ion, and enzyme activator on mannan production were evaluated using factional design. The mathematical model was established\\u000a by the quadratic rotary combination design through

Hong-Zhi Liu; Qiang Wang; Yuan-Yuan Liu; Fang Fang

2009-01-01

170

Evaluation of wet-feeding wheat-based diets containing Saccharomyces cerevisiae to broiler chickens  

Microsoft Academic Search

1. This experiment investigated the effects of water and Saccharomyces cerevisiae added to wheat-based diets on gastrointestinal, blood and performance parameters of broiler chickens.2. A total of 160 one-d-old male broiler chicks were given air-dry or wet diets, with or without S. cerevisiae supplementation (0 and 20?g\\/kg air-dry feed) ad libitum to 42?d.3. Feeding broilers with a diet mixed with

M. Afsharmanesh; M. Barani; F. G. Silversides

2010-01-01

171

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

PubMed Central

Little information on the effects of cyclohexane at the cellular or subcellular level is available. In Saccharomyces cerevisiae, cyclohexane inhibited respiration and diverse energy-dependent processes. In mitochondria isolated from S. cerevisiae, oxygen uptake and ATP synthesis were inhibited, although ATPase activity was not affected. Cyclohexane effects were similar to those reported for beta-pinene and limonene, suggesting that the cyclohexane ring in these monoterpenes may be a determinant for their biological activities. PMID:2202257

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

1990-01-01

172

Studies of anaerobic and aerobic glycolysis in Saccharomyces cerevisiae  

SciTech Connect

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)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.

den Hollander, J.A.; Ugurbil, K.; Brown, T.R.; Bednar, M.; Redfield, C.; Shulman, R.G.

1986-01-14

173

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

PubMed

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

174

Phenotypic and metabolic traits of commercial Saccharomyces cerevisiae yeasts.  

PubMed

Currently, pursuing yeast strains that display both a high potential fitness for alcoholic fermentation and a favorable impact on quality is a major goal in the alcoholic beverage industry. This considerable industrial interest has led to many studies characterizing the phenotypic and metabolic traits of commercial yeast populations. In this study, 20 Saccharomyces cerevisiae strains from different geographical origins exhibited high phenotypic diversity when their response to nine biotechnologically relevant conditions was examined. Next, the fermentation fitness and metabolic traits of eight selected strains with a unique phenotypic profile were evaluated in a high-sugar synthetic medium under two nitrogen regimes. Although the strains exhibited significant differences in nitrogen requirements and utilization rates, a direct relationship between nitrogen consumption, specific growth rate, cell biomass, cell viability, acetic acid and glycerol formation was only observed under high-nitrogen conditions. In contrast, the strains produced more succinic acid under the low-nitrogen regime, and a direct relationship with the final cell biomass was established. Glucose and fructose utilization patterns depended on both yeast strain and nitrogen availability. For low-nitrogen fermentation, three strains did not fully degrade the fructose. This study validates phenotypic and metabolic diversity among commercial wine yeasts and contributes new findings on the relationship between nitrogen availability, yeast cell growth and sugar utilization. We suggest that measuring nitrogen during the stationary growth phase is important because yeast cells fermentative activity is not exclusively related to population size, as previously assumed, but it is also related to the quantity of nitrogen consumed during this growth phase. PMID:24949272

Barbosa, Catarina; Lage, Patrícia; Vilela, Alice; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

2014-01-01

175

Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium  

PubMed Central

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 ?1278b 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. PMID:25009170

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

2014-01-01

176

Saccharomyces cerevisiae Genes Involved in Survival of Heat Shock  

PubMed Central

The heat-shock response in cells, involving increased transcription of a specific set of genes in response to a sudden increase in temperature, is a highly conserved biological response occurring in all organisms. Despite considerable attention to the processes activated during heat shock, less is known about the role of genes in survival of a sudden temperature increase. Saccharomyces cerevisiae genes involved in the maintenance of heat-shock resistance in exponential and stationary phase were identified by screening the homozygous diploid deletants in nonessential genes and the heterozygous diploid mutants in essential genes for survival after a sudden shift in temperature from 30 to 50°. More than a thousand genes were identified that led to altered sensitivity to heat shock, with little overlap between them and those previously identified to affect thermotolerance. There was also little overlap with genes that are activated or repressed during heat-shock, with only 5% of them regulated by the heat-shock transcription factor. The target of rapamycin and protein kinase A pathways, lipid metabolism, vacuolar H+-ATPase, vacuolar protein sorting, and mitochondrial genome maintenance/translation were critical to maintenance of resistance. Mutants affected in l-tryptophan metabolism were heat-shock resistant in both growth phases; those affected in cytoplasmic ribosome biogenesis and DNA double-strand break repair were resistant in stationary phase, and in mRNA catabolic processes in exponential phase. Mutations affecting mitochondrial genome maintenance were highly represented in sensitive mutants. The cell division transcription factor Swi6p and Hac1p involved in the unfolded protein response also play roles in maintenance of heat-shock resistance. PMID:24142923

Jarolim, Stefanie; Ayer, Anita; Pillay, Bethany; Gee, Allison C.; Phrakaysone, Alex; Perrone, Gabriel G.; Breitenbach, Michael; Dawes, Ian W.

2013-01-01

177

Metabolism and Regulation of Glycerolipids in the Yeast Saccharomyces cerevisiae  

PubMed Central

Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways. PMID:22345606

Henry, Susan A.; Kohlwein, Sepp D.; Carman, George M.

2012-01-01

178

Genotoxicity of bergapten and bergamot oil in Saccharomyces cerevisiae.  

PubMed

In order to determine the genotoxic potential of bergapten (5-methoxypsoralen (5-MOP] and bergamot oil (BO), the genetic effects of 5-MOP and BO (containing equivalent amounts of 5-MOP) were studied in haploid and diploid yeast (Saccharomyces cerevisiae) using solar simulated radiation (SSR). At equal doses of SSR, equal concentrations of 5-MOP alone or 5-MOP in BO have a similar influence on survival and on the induction of cytoplasmic "petite" mutations, reverse and forward mutations, mitotic gene conversion and genetically aberrant colonies including mitotic crossing over. No reciprocity is found between SSR dose and 5-MOP concentration for cytotoxic, mutagenic and recombinogenic effects. In the presence of chemical filters (Parsol 1789, a UVA filter, and Parsol MCX, a cinnamate derivative acting as a UVB filter) considerable protection is observed against the induction of genetic effects by 5-MOP and BO containing 5-MOP in haploid and diploid cells. As indicated by the lower induction kinetics, the protection is higher than expected from the light-absorbing properties, suggesting photochemical interaction. The protection is slightly higher for BO than for 5-MOP. The induction of genetic effects by 5-MOP alone or BO containing 5-MOP is independent of oxygen. Experiments on suction blister fluids taken from patients after topical treatment with BO containing 5-MOP indicate that in comparison with water the bioavailability and thus the genotoxic effects of the compounds are decreased. Moreover, in addition to the filtering effect against the photoinduced genotoxic effects of BO, the presence of chemical filters apparently reduces the penetration of BO containing 5-MOP and provides a reduction in biological effectiveness. PMID:2128325

Averbeck, D; Averbeck, S; Dubertret, L; Young, A R; Morlière, P

1990-11-01

179

Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae.  

PubMed

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

180

Phenotypic and metabolic traits of commercial Saccharomyces cerevisiae yeasts  

PubMed Central

Currently, pursuing yeast strains that display both a high potential fitness for alcoholic fermentation and a favorable impact on quality is a major goal in the alcoholic beverage industry. This considerable industrial interest has led to many studies characterizing the phenotypic and metabolic traits of commercial yeast populations. In this study, 20 Saccharomyces cerevisiae strains from different geographical origins exhibited high phenotypic diversity when their response to nine biotechnologically relevant conditions was examined. Next, the fermentation fitness and metabolic traits of eight selected strains with a unique phenotypic profile were evaluated in a high-sugar synthetic medium under two nitrogen regimes. Although the strains exhibited significant differences in nitrogen requirements and utilization rates, a direct relationship between nitrogen consumption, specific growth rate, cell biomass, cell viability, acetic acid and glycerol formation was only observed under high-nitrogen conditions. In contrast, the strains produced more succinic acid under the low-nitrogen regime, and a direct relationship with the final cell biomass was established. Glucose and fructose utilization patterns depended on both yeast strain and nitrogen availability. For low-nitrogen fermentation, three strains did not fully degrade the fructose. This study validates phenotypic and metabolic diversity among commercial wine yeasts and contributes new findings on the relationship between nitrogen availability, yeast cell growth and sugar utilization. We suggest that measuring nitrogen during the stationary growth phase is important because yeast cells fermentative activity is not exclusively related to population size, as previously assumed, but it is also related to the quantity of nitrogen consumed during this growth phase. PMID:24949272

2014-01-01

181

Metabolic engineering of muconic acid production in Saccharomyces cerevisiae.  

PubMed

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

182

A Late Form of Nucleophagy in Saccharomyces cerevisiae  

PubMed Central

Autophagy encompasses several processes by which cytosol and organelles can be delivered to the vacuole/lysosome for breakdown and recycling. We sought to investigate autophagy of the nucleus (nucleophagy) in the yeast Saccharomyces cerevisiae by employing genetically encoded fluorescent reporters. The use of such a nuclear reporter, n-Rosella, proved the basis of robust assays based on either following its accumulation (by confocal microscopy), or degradation (by immunoblotting), within the vacuole. We observed the delivery of n-Rosella to the vacuole only after prolonged periods of nitrogen starvation. Dual labeling of cells with Nvj1p-EYFP, a nuclear membrane reporter of piecemeal micronucleophagy of the nucleus (PMN), and the nucleoplasm-targeted NAB35-DsRed.T3 allowed us to detect PMN soon after the commencement of nitrogen starvation whilst delivery to the vacuole of the nucleoplasm reporter was observed only after prolonged periods of nitrogen starvation. This later delivery of nuclear components to the vacuole has been designated LN (late nucleophagy). Only a very few cells showed simultaneous accumulation of both reporters (Nvj1p-EYFP and NAB35-DsRed.T3) in the vacuole. We determined, therefore, that delivery of the two respective nuclear reporters to the vacuole is temporally and spatially separated. Furthermore, our data suggest that LN is mechanistically distinct from PMN because it can occur in nvj1? and vac8? cells, and does not require ATG11. Nevertheless, a subset of the components of the core macroautophagic machinery is required for LN as it is efficiently inhibited in null mutants of several autophagy-related genes (ATG) specifying such components. Moreover, the inhibition of LN in some mutants is accompanied by alterations in nuclear morphology. PMID:22768199

Mijaljica, Dalibor; Prescott, Mark; Devenish, Rodney J.

2012-01-01

183

Anti-Saccharomyces cerevisiae antibodies (ASCA) and autoimmune liver diseases  

PubMed Central

Antibodies to the baker's yeast Saccharomyces cerevisiae (ASCA), recently proposed as a serological marker of Crohn's disease, have also been detected in other autoimmune disorders. The aim of this study was to determine prevalence and clinical significance of ASCA in autoimmune liver disease. The presence of IgG and IgA ASCA was evaluated using a commercially available immunoassay in 215 patients with autoimmune liver disease (primary biliary cirrhosis, PBC, 123 cases; autoimmune hepatitis, AIH, 67 cases; primary sclerosing cholangitis, PSC, 25 cases), 48 with inflammatory bowel disease and 19 healthy blood donors. Anti neutrophil cytoplasmic antibodies with the perinuclear pattern (p-ANCA) were assessed by indirect immunofluorescence in PSC patients. The main clinical and biochemical parameters between ASCA-positive and negative patients were analysed and compared. ASCA are predominant in Crohn's disease (70%); among liver patients, PSC and AMA-negative PBC show the highest ASCA prevalence (53% and 44%). In PBC ASCA correlate with higher levels of circulating IgA (P < 0·05). In PSC the detection of either ASCA or p-ANCA is neither associated with any clinical or biochemical feature, nor with an underlying inflammatory bowel disease. ASCA can not be considered an additional serological marker of autoimmune liver disease, but the possibility of detecting such a reactivity in autoimmune liver disorders should be considered; their correlation with elevated IgA in PBC suggests that ASCA may be an indirect sign of enhanced mucosal immunity; in PSC patients neither ASCA nor p-ANCA predict the occurrence of a concomitant inflammatory bowel disease. PMID:12780695

MURATORI, P; MURATORI, L; GUIDI, M; MACCARIELLO, S; PAPPAS, G; FERRARI, R; GIONCHETTI, P; CAMPIERI, M; BIANCHI, F B

2003-01-01

184

Anti-Saccharomyces cerevisiae antibodies (ASCA) and autoimmune liver diseases.  

PubMed

Antibodies to the baker's yeast Saccharomyces cerevisiae (ASCA), recently proposed as a serological marker of Crohn's disease, have also been detected in other autoimmune disorders. The aim of this study was to determine prevalence and clinical significance of ASCA in autoimmune liver disease. The presence of IgG and IgA ASCA was evaluated using a commercially available immunoassay in 215 patients with autoimmune liver disease (primary biliary cirrhosis, PBC, 123 cases; autoimmune hepatitis, AIH, 67 cases; primary sclerosing cholangitis, PSC, 25 cases), 48 with inflammatory bowel disease and 19 healthy blood donors. Anti neutrophil cytoplasmic antibodies with the perinuclear pattern (p-ANCA) were assessed by indirect immunofluorescence in PSC patients. The main clinical and biochemical parameters between ASCA-positive and negative patients were analysed and compared. ASCA are predominant in Crohn's disease (70%); among liver patients, PSC and AMA-negative PBC show the highest ASCA prevalence (53% and 44%). In PBC ASCA correlate with higher levels of circulating IgA (P < 0.05). In PSC the detection of either ASCA or p-ANCA is neither associated with any clinical or biochemical feature, nor with an underlying inflammatory bowel disease. ASCA can not be considered an additional serological marker of autoimmune liver disease, but the possibility of detecting such a reactivity in autoimmune liver disorders should be considered; their correlation with elevated IgA in PBC suggests that ASCA may be an indirect sign of enhanced mucosal immunity; in PSC patients neither ASCA nor p-ANCA predict the occurrence of a concomitant inflammatory bowel disease. PMID:12780695

Muratori, P; Muratori, L; Guidi, M; Maccariello, S; Pappas, G; Ferrari, R; Gionchetti, P; Campieri, M; Bianchi, F B

2003-06-01

185

Selection of in vivo deletions in Saccharomyces cerevisiae.  

PubMed Central

A general screening procedure has been devised for the selection of in vivo-generated deletions in haploid Saccharomyces cerevisiae cells. It is based on the introduction into a cyh2 host (resistant to the drug cycloheximide) of a tandemly duplicated CYH2 gene (a dominant allele, conferring sensitivity to cycloheximide), and subsequent selection for Cyhr derivatives. The duplicated CYH2 gene has been introduced on CEN ARS plasmids or integrated into chromosome II. A variable but significant proportion of the Cyhr derivatives of such transformants were deletion mutants in which both CYH2 copies had suffered deletions. Some of the deletions extended into sequences outside the tandemly duplicated CYH2 gene. A total of 61 independently selected deletions ranged in length from 3.1 to over 20 kilobases and had no obvious preferred endpoints. Restriction analysis showed that other frequently isolated Cyhr derivatives appeared to retain one of the two CYH2 copies. Such single-copy derivatives of CEN ARS plasmids did not contain a functional CYH2 gene. The frequency of true deletions in CEN ARS plasmids, of approximately 10(-7) per viable cell, was comparable in RAD52 and rad52 strains. Chromosomal deletions, which occurred at a frequency of approximately 10(-8) per viable cell, were observed only in rad52 hosts. Derivatives exhibiting an additional altered phenotype, such as the inactivation of a neighboring gene or, less frequently, the transcriptional activation of a previously silent gene, were isolated by screening deletion mutants. These results show that the method described can be used for in vivo deletion mapping or for the generation of gene fusions. PMID:2842289

Bitoun, R; Zamir, A

1988-01-01

186

A vector set for systematic metabolic engineering in Saccharomyces cerevisiae.  

PubMed

A set of shuttle vectors was constructed to facilitate expression of genes for metabolic engineering in Saccharomyces cerevisiae. Selectable markers include the URA3, TRP1, MET15, LEU2-d8, HIS3 and CAN1 genes. Differential expression of genes can be achieved as each marker is available on both CEN/ARS- and 2 µ-containing plasmids. Unique restriction sites downstream of TEF1, PGK1 or HXT7-391 promoters and upstream of the CYC1 terminator allow insertion of open-reading frame cassettes for expression. Furthermore, a fragment appropriate for integration into the genome via homologous recombination can be readily generated in a polymerase chain reaction. Vector marker genes are flanked by loxP recognition sites for the CreA recombinase to allow efficient site-specific marker deletion and recycling. Expression and copy number were characterized for representative high- and low-copy vectors carrying the different marker and promoter sequences. Metabolic engineering typically requires the stable introduction of multiple genes and genomic integration is often preferred. This requires an expanded number of stable expression sites relative to standard gene expression studies. This study demonstrated the practicality of polymerase chain reaction amplification of an expression cassette and genetic marker, and subsequent replacement of endogenous retrotransposons by homologous recombination with flanking sequences. Such reporters were expressed comparably to those inserted at standard integration loci. This expands the number of available characterized integration sites and demonstrates that such sites provide a virtually inexhaustible pool of integration targets for stable expression of multiple genes. Together these vectors and expression loci will facilitate combinatorial gene expression for metabolic engineering. PMID:20936606

Fang, Fang; Salmon, Kirsty; Shen, Michael W Y; Aeling, Kimberly A; Ito, Elaine; Irwin, Becky; Tran, Uyen Phuong C; Hatfield, G Wesley; Da Silva, Nancy A; Sandmeyer, Suzanne

2011-02-01

187

Accumulation and chemical states of radiocesium by fungus Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

188

Isolation of xylose reductase gene of Pichia stipitis and its expression in Saccharomyces cerevisiae  

SciTech Connect

A NADPH/NADH-dependent xylose reductase gene was isolated from the xylose-assimilating yeast, Pichia stipitis. DNA sequence analysis showed that the gene consists of 951 bp. The gene introduced in Saccharomyces cerevisiae was transcribed to mRNA, and a considerable amount of enzyme activity was observed constitutively, whereas transcription and translation in P steps were inducible. S. cerevisiae carrying the xylose reductase gene could not, however, grow on xylose medium, and could not produce ethanol from xylose. Since xylose uptake and accumulation of xylitol by S. cerevisiae were observed, the conversion of xylitol to xylulose seemed to be limited.

Takuma, Shinya; Nakashima, Noriyuki; Tantirungkij, Manee [Osaka Univ. (Japan)] [and others

1991-12-31

189

Comparative characterization of endo-polygalacturonase ( Pgu1 ) from Saccharomyces cerevisiae and Saccharomyces paradoxus under winemaking conditions  

Microsoft Academic Search

Wine strains of Saccharomyces cerevisiae have no to weak natural pectinase activity, despite their genetic ability to secrete an endo-polygalacturonase. The addition\\u000a of external pectinase of fungal origin has therefore become a common step of winemaking in order to enhance the extraction\\u000a of compounds located in the grape berry skins during maceration and to ease wine clarification after maturation. Recently,

Alexis Eschstruth; Benoit Divol

190

Effects of immobilization on growth, fermentation properties, and macromolecular composition of Saccharomyces cerevisiae attached to gelatin  

Microsoft Academic Search

The kinetic properties of Saccharomyces cerevisiae immobilized on crosslinked gelatin were found to be substantially different from those of the suspended yeast. Batch fermentation experiments conducted in a gradientless reaction system allowed comparison of immobilized cell and suspended cell performance. The specific rate of ethanol production by the immobilized cells was 40-50% greater than for the suspended yeast. The immobilized

Pauline M. Doran; James E. Bailey

1986-01-01

191

Minear, S., et al Curcumin inhibits growth of Saccharomyces cerevisiae1  

E-print Network

Minear, S., et al 1 Curcumin inhibits growth of Saccharomyces cerevisiae1 through iron chelation2 3 of print on 9 September 2011 #12;Minear, S., et al 2 Abstract (limit 250 words)46 47 Curcumin, a polyphenol of ailments. Interest in curcumin has49 increased recently, with on-going clinical trials exploring curcumin

Stearns, Tim

192

Role of Hexose Transport in Control of Glycolytic Flux in Saccharomyces cerevisiae  

Microsoft Academic Search

The yeast Saccharomyces cerevisiae predominantly ferments glucose to ethanol at high external glucose concentrations, irrespective of the presence of oxygen. In contrast, at low external glucose concentrations and in the presence of oxygen, as in a glucose-limited chemostat, no ethanol is produced. The importance of the external glucose concentration suggests a central role for the affinity and maximal transport rates

Karin Elbing; Christer Larsson; Roslyn M. Bill; Eva Albers; Jacky L. Snoep; Eckhard Boles; Stefan Hohmann; Lena Gustafsson

2004-01-01

193

Effect of continuous feeding of galactose on the production of recombinant glucose oxidase using Saccharomyces cerevisiae  

Microsoft Academic Search

A recombinant strain of Saccharomyces cerevisiae harboring GOD gene originated from Aspergillus niger was used for the production of extracellular glucose oxidase. The effect of continuous galactose feeding on the induction of GAL-10 promoter was examined in a 5 l bioreactor. The highest enzyme production level (164 U cmх) was achieved at 96 h of cultivation. The production performance was

A. Kapat; J. K. Jung; Y. H. Park

2000-01-01

194

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

195

A Role for Saccharomyces cerevisiae Cul8 Ubiquitin Ligase in Proper Anaphase Progression*  

E-print Network

A Role for Saccharomyces cerevisiae Cul8 Ubiquitin Ligase in Proper Anaphase Progression* Received, Chapel Hill, North Carolina 27599-7295 We have undertaken a study of the yeast cullin family members Cul3 and Cul8, as little is known about their biochemical and physiological functions. We demon- strate

Xiong, Yue

196

Phosphate uptake in Saccharomyces cerevisiae Hansen wild type and phenotypes exposed to space flight irradiation.  

PubMed Central

Rates of phosphate uptake were approximately twice as great for Saccharomyces cerevisiae single-cell phenotypic isolates exposed to space parameters as for the wild-type ground control. Quantitative determination of 32P was performed by liquid scintillation spectrometry utilizing Cerenkov radiation counting techniques. PMID:395899

Berry, D; Volz, P A

1979-01-01

197

Crystal Structure of Saccharomyces cereVisiae 3-Phosphoadenosine-5-phosphosulfate Reductase Complexed with Adenosine  

E-print Network

Crystal Structure of Saccharomyces cereVisiae 3-Phosphoadenosine-5-phosphosulfate Reductase potential drug targets for human pathogens. Here, we present the 2.05 Ã? resolution crystal structure from the S of Cys245 and may serve as a catalytic base to deprotonate the active site cysteine

Fisher, Andrew J.

198

[Biosynthesis of CdS quantum dots in Saccharomyces cerevisiae and spectroscopic characterization].  

PubMed

In the present work, CdS quantum dots (QDs) were successfully biosynthesized at room temperature by using saccharomyces cerevisiae yeast as a carrier. Fluorescence emission spectra, ultraviolet-visible (UV/Vis) absorption spectra, and inverted fluorescence microscope images confirmed that saccharomyces cerevisiae can be used to biosynthesize CdS QDs. The as-prepared CdS QDs show the fluorescence emission peak at 443 nm and emit blue-green fluorescence under UV light (with excitation at 365 nm). Transmission electron microscopy (TEM) was applied to characterize the as-prepared CdS QDs and the TEM results showed that the as-prepared CdS QDs had the structure of hexagonal wurtzite. Fluorescence emission spectrum and UV/Vis absorption spectrum were used as the performance indicatiors to study the effects of saccharomyces cerevisiae yeast incubation times, reactant Cd2+ concentrations and reaction times on CdS QDs synthesis. Saccharomyces cerevisiae yeast grown in early stable phase can get the highest fluorescence intensity of CdS QDs when they were co-cultured with 0.5 mmol x L(-1) of Cd2+ with 24 h incubation time. Furthermore, much more CdS QDs can be obtained by changing the culture medium during the synthesis process. PMID:22715791

Huang, Huai-qing; He, Ming-xin; Wang, Wen-xing; Liu, Jin-ling; Mi, Cong-cong; Xu, Shu-kun

2012-04-01

199

The uptake of different iron salts by the yeast Saccharomyces cerevisiae  

PubMed Central

Yeasts can be enriched with microelements, including iron; however, special physicochemical conditions are required to formulate a culture media that promotes both yeast growth and iron uptake. Different iron sources do not affect biomass formation; however, considering efficacy, cost, stability, and compatibility with Saccharomyces cerevisiae metabolism, ferrous sulphate is recommended. PMID:25242932

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

2014-01-01

200

Lipolytic activity of Williopsis californica and Saccharomyces cerevisiae in extra virgin olive oil  

Microsoft Academic Search

Inoculation trials performed with three strains of yeasts, isolated from extra virgin olive oil, Williopsis californica 1639, Saccharomyces cerevisiae 1525 and Candida boidinii 1638, demonstrated that some yeast can lower the quality of the oil during storage. Laboratory tests highlighted a substantial increase in the total diglycerides and free fatty acids in the samples of oil inoculated with the lipase-producing

G. Ciafardini; B. A. Zullo; G. Cioccia; A. Iride

2006-01-01

201

Modeling growth and telomere dynamics in Saccharomyces cerevisiae Peter Olofsson a,, Alison A. Bertuch b  

E-print Network

Modeling growth and telomere dynamics in Saccharomyces cerevisiae Peter Olofsson a,Ã?, Alison A Accepted 2 December 2009 MSC: 60G99 60K99 62P10 92D25 Keywords: Telomere Branching process Yeast Fibonacci of slowing due to critical telomere shortening. The explanation for this phenomenon is that some cells engage

Olofsson, Peter

202

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

Microsoft Academic Search

Mating type interconversion in Saccharomyces cerevisiae occurs by transposition of copies of the a or ..cap alpha.. mating type cassettes from inactive loci, HML and HMR, to an active locus, MAT. The lack of expression of the a and ..cap alpha.. genes at the silent loci results from repression by trans-acting regulators encoded by SIR (Silent Information Regulator) genes. In

Jasper Rine; Ira Herskowitz

1987-01-01

203

Filamentous growth of the budding yeast Saccharomyces cerevisiae induced by overexpression of the WHI2 gene  

Microsoft Academic Search

The WHI2 gene of the budding yeast Saccharomyces cerevisiae is required for the arrest of cell proliferation upon nutrient exhaustion: whi2 mutants carry on dividing and in the absence of growth become abnormally small. It is reported here that overexpression of Whi2 from the GAL1 promoter results in filamentous growth - cells fail to complete cytokinesis, the budding pattern changes

P. A. Radcliffe; K. M. Binley; J. Trevethick; M. Hall; P. E. Sudbery

1997-01-01

204

Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae  

Microsoft Academic Search

BACKGROUND: Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast Saccharomyces cerevisiae preserve their native allergenic properties and whether the yeast native surface glycoproteins

Irina Borodina; Bettina M Jensen; Ib Søndergaard; Lars K Poulsen

2010-01-01

205

Saccharomyces cerevisiae Med9 comprises two functionally distinct domains that play different roles in transcriptional regulation  

Microsoft Academic Search

Mediator is one of the most important co-activators that function in eukaryotic transcriptional regulation. In Saccharomyces cerevisiae, Mediator is comprised of 25 subunits belonging to four structurally distinct modules: Head, Middle, Tail, and Cyc-C. Although each module plays a critical role in the regulation of a distinct set of genes, the precise molecular mechanisms remain unclear. To gain new insight

Hiroyuki Takahashi; Koji Kasahara; Tetsuro Kokubo

2009-01-01

206

Thiamin metabolism and thiamin diphosphate-dependent enzymes in the yeast Saccharomyces cerevisiae: genetic regulation  

Microsoft Academic Search

The yeast Saccharomyces cerevisiae utilises external thiamin for the production of thiamin diphosphate (ThDP) or can synthesise the cofactor itself. Prior to uptake into the cell thiamin phosphates are first hydrolysed and thiamin is taken up as free vitamin which is then pyrophosphorylated by a pyrophosphokinase. Synthesis of ThDP starts with the production of hydroxyethylthiazole and hydroxymethylpyrimidine. Those are linked

Stefan Hohmann; Peter A Meacock

1998-01-01

207

High Osmolarity Extends Life Span in Saccharomyces cerevisiae by a Mechanism Related to Calorie Restriction  

Microsoft Academic Search

Calorie restriction (CR) extends life span in many different organisms, including mammals. We describe here a novel pathway that extends the life span of Saccharomyces cerevisiae mother cells but does not involve a reduction in caloric content of the media, i.e., there is growth of yeast cells in the presence of a high concentration of external osmolytes. Like CR, this

Matt Kaeberlein; Alex A. Andalis; Gerald R. Fink; Leonard Guarente

2002-01-01

208

Determination of Mitotic Recombination Rates by Fluctuation Analysis in Saccharomyces cerevisiae  

Microsoft Academic Search

Summary The study of recombination in Saccharomyces cerevisiae benefits from the availability of assay systems that select for recombinants, allowing the study of spontaneous events that rep- resent natural assaults on the genome. However, the rarity of such spontaneous recombination requires selection of events that occur over many generations in a cell culture, and the number of recombinants increases exponentially

Rachelle Miller Spell; Sue Jinks-Robertson

209

Dissociation of Import of the Rieske Iron-Sulfur Protein into Saccharomyces cerevisiae Mitochondria from Proteolytic  

E-print Network

Dissociation of Import of the Rieske Iron-Sulfur Protein into Saccharomyces cerevisiae Mitochondria into the matrix space of mitochondria by inhibiting a step other than proteolysis of the presequence. The Rieske. The iron-sulfur protein is then post-translationally imported into the mitochondria where it is inserted

Trumpower, Bernard L.

210

NDT80, a meiosis-specific gene required for exit from pachytene in Saccharomyces cerevisiae  

SciTech Connect

This report describes the identification of a new meiosis-specific gene of Saccharomyces cerevisiae called NDT80. DNA cloning and molecular analysis revealed that the NDT80 gene maps on the right arm of chromosome 8 and is transcribed during middle meiotic prophase. 82 refs., 6 figs., 3 tabs.

Xu, Liuzhong; Ajimura, M.; Padmore, R.; Klein, C.; Kleckner, N. [Harvard Univ., Cambridge, MA (United States)

1995-12-01

211

Meiotic effects of DNA-defective cell division cycle mutations of Saccharomyces cerevisiae  

Microsoft Academic Search

The meiotic effects of several cell division cycle (cdc) mutations of Saccharomyces cerevisiae have been investigated by electron microscopy and by genetic and biochemical methods. Diploid strains homozygous for cdc mutations known to confer defects on vegetative DNA synthesis were subjected to restrictive conditions during meiosis. Electron microscopy revealed that all four mutants were conditionally arrested in meiosis after duplication

David Schild; Breck Byers

1978-01-01

212

Metabolic-Flux Profiling of the Yeasts Saccharomyces cerevisiae and Pichia stipitis  

Microsoft Academic Search

The so far largely uncharacterized central carbon metabolism of the yeast Pichia stipitis was explored in batch and glucose-limited chemostat cultures using metabolic-flux ratio analysis by nuclear magnetic reso- nance. The concomitantly characterized network of active metabolic pathways was compared to those identified in Saccharomyces cerevisiae, which led to the following conclusions. (i) There is a remarkably low use of

Jocelyne Fiaux; Z. Petek Cakar; Marco Sonderegger; Kurt Wuthrich; Thomas Szyperski; Uwe Sauer

2003-01-01

213

Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

214

Biochemistry, cell biology and molecular biology of lipids ofSaccharomyces cerevisiae  

Microsoft Academic Search

The yeast Saccharomyces cerevisiae is a powerful experimental system to study biochemical, cell biological and molecular biological aspects of lipid synthesis. Most but not all genes encoding enzymes involved in fatty acid, phospholipid, sterol or sphingolipid biosynthesis of this unicellular eukaryote have been cloned, and many gene products have been functionally characterized. Less information is available about genes and gene

Gunther Daum; Norman D. Lees; Martin Bard; Robert Dickson

1998-01-01

215

Degradation of conjugated linoleic acid isomers in the yeast Saccharomyces cerevisiae.  

PubMed

Propagation of Saccharomyces cerevisiae cells in conjugated linoleic acid (CLA) medium resulted in activation of the transcriptional machinery that responds to fatty acids. Cells utilized efficiently trans-10,cis-12 CLA, but not the corresponding cis-9,trans-11 isomer, probably due to the formation of cis-3,trans-5-dienoyl-CoA intermediates that are recalcitrant to beta-oxidation. PMID:11566445

Gurvitz, A; Hamilton, B; Ruis, H; Hartig, A; Hiltunen, J K

2001-09-28

216

Effect of yeast culture, Saccharomyces cerevisiae, on ruminal fermentation during adaptation to high-concentrate feeding  

E-print Network

Effect of yeast culture, Saccharomyces cerevisiae, on ruminal fermentation during adaptation in the fermentation pathway, and can accumulate rapidly (Mackie and Gilchrist, 1979, Appl Environ Microbiol, 38, 422 (SC), on the stabilization of ruminal fermentation. The objective of this study was to provide

Boyer, Edmond

217

Null mutants of Saccharomyces cerevisiae Cu,Zn superoxide dismutase: characterization and spontaneous mutation rates.  

PubMed Central

Deletion-replacement mutations of the Saccharomyces cerevisiae Cu,Zn superoxide dismutase gene were constructed. They were exquisitely sensitive to redox cycling drugs and showed slight sensitivity to other agents. The aerobic spontaneous mutation rate was three- to fourfold higher in sod1 delta 1 mutants, while the anaerobic rate was similar to that of the wild type. PMID:1885557

Gralla, E B; Valentine, J S

1991-01-01

218

Mixing of vineyard and oak-tree ecotypes of Saccharomyces cerevisiae in North American vineyards.  

PubMed

Humans have had a significant impact on the distribution and abundance of Saccharomyces cerevisiae through its widespread use in beer, bread and wine production. Yet, similar to other Saccharomyces species, S. cerevisiae has also been isolated from habitats unrelated to fermentations. Strains of S. cerevisiae isolated from grapes, wine must and vineyards worldwide are genetically differentiated from strains isolated from oak-tree bark, exudate and associated soil in North America. However, the causes and consequences of this differentiation have not yet been resolved. Historical differentiation of these two groups may have been influenced by geographic, ecological or human-associated barriers to gene flow. Here, we make use of the relatively recent establishment of vineyards across North America to identify and characterize any active barriers to gene flow between these two groups. We examined S. cerevisiae strains isolated from grapes and oak trees within three North American vineyards and compared them to those isolated from oak trees outside of vineyards. Within vineyards, we found evidence of migration between grapes and oak trees and potential gene flow between the divergent oak-tree and vineyard groups. Yet, we found no vineyard genotypes on oak trees outside of vineyards. In contrast, Saccharomyces paradoxus isolated from the same sources showed population structure characterized by isolation by distance. The apparent absence of ecological or genetic barriers between sympatric vineyard and oak-tree populations of S. cerevisiae implies that vineyards play an important role in the mixing between these two groups. PMID:23286354

Hyma, Katie E; Fay, Justin C

2013-06-01

219

Genomic Screen for Vacuolar Protein Sorting Genes in Saccharomyces cerevisiaeD?  

PubMed Central

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 the corresponding genes had been previously implicated in vacuolar protein sorting, whereas the remaining 93 had either been identified in screens for other cellular processes or were only known as hypothetical open reading frames. Among these 93 were genes encoding: 1) the Ras-like GTP-binding proteins Arl1p and Arl3p, 2) actin-related proteins such as Arp5p and Arp6p, 3) the monensin and brefeldin A hypersensitivity proteins Mon1p and Mon2p, and 4) 15 novel proteins designated Vps61p-Vps75p. Most of the novel gene products were involved only in the carboxypeptidase Y pathway, whereas a few, including Mon1p, Mon2p, Vps61p, and Vps67p, appeared to be involved in both the carboxypeptidase Y and alkaline phosphatase pathways. Mutants lacking some of the novel gene products, including Arp5p, Arp6p, Vps64p, and Vps67p, were severely defective in secretion of mature ?-factor. Others, such as Vps61p, Vps64p, and Vps67p, displayed defects in the actin cytoskeleton at 30°C. The identification and phenotypic characterization of these novel mutants provide new insights into the mechanisms of vacuolar protein sorting, most notably the probable involvement of the actin cytoskeleton in this process. PMID:12134085

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

2002-01-01

220

Modeling disease-related proteins in Saccharomyces cerevisiae : insights into alpha-synuclein and TorsinA biology  

E-print Network

The yeast Saccharomyces cerevisiae has long been used to model complex cellular processes. As a eukaryote, much of its fundamental biology is conserved with higher organisms. As a single-celled, genetically tractable ...

Valastyan, Julie S. (Julie Suzanne)

2013-01-01

221

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

222

Alkyl hydroperoxide reductase 1 protects Saccharomyces cerevisiae against metal ion toxicity and glutathione depletion.  

PubMed

Alkyl hydroperoxide reductase 1 (Ahp1p) is a thioredoxin peroxidase of the peroxiredoxin family expressed by Saccharomyces cerevisiae. Recently, disruption of the AHP1 gene has shown that the gene is not essential for yeast growth on glucose medium but revealed a high sensitivity of null mutants to organic peroxides, suggesting that Ahp1p is an important enzyme implicated in oxidative stress protection in S. cerevisiae. To gain insight into antioxidant enzymatic mechanisms involved in cell protection against metal toxicity and glutathione depletion, we investigated the resistance of S. cerevisiae, in which the AHP1 gene was disrupted, against several metals and diethyl maleate, a glutathione depleting agent. We report that Ahp1p protects yeast against toxicity induced by copper, cobalt, chromium, arsenite, arsenate, mercury, zinc and diethyl maleate, suggesting that Ahp1p plays an important role in S. cerevisiae in the protection against metals possibly by reducing peroxides generated in cells by these compounds. PMID:12270680

Nguyên-nhu, Nhu Tiên; Knoops, Bernard

2002-10-01

223

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

PubMed

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

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

2013-05-01

224

Mixing of vineyard and oak-tree ecotypes of Saccharomyces cerevisiae in North American vineyards  

PubMed Central

Humans have had a significant impact on the distribution and abundance of Saccharomyces cerevisiae through its widespread use in beer, bread and wine production. Yet, similar to other Saccharomyces species, S. cerevisiae has also been isolated from habitats unrelated to fermentations. Strains of S. cerevisiae isolated from grapes, wine must and vineyards worldwide are genetically differentiated from strains isolated from oak-tree bark, exudate and associated soil in North America. However, the causes and consequences of this differentiation have not yet been resolved. Historical differentiation of these two groups may have been influenced by geographic, ecological or human-associated barriers to gene flow. Here, we make use of the relatively recent establishment of vineyards across North America to identify and characterize any active barriers to gene flow between these two groups. We examined S. cerevisiae strains isolated from grapes and oak-trees within three North American vineyards and compared them to those isolated from oak-trees outside of vineyards. Within vineyards we found evidence of migration between grapes and oak-trees and potential gene flow between the divergent oak-tree and vineyard groups. Yet, we found no vineyard genotypes on oak-trees outside of vineyards. In contrast, S. paradoxus isolated from the same sources showed population structure characterized by isolation by distance. The apparent absence of ecological or genetic barriers between sympatric vineyard and oak-tree populations of S. cerevisiae implies that vineyards play an important role in the mixing between these two groups. PMID:23286354

Hyma, Katie E.; Fay, Justin C.

2012-01-01

225

The ASP3 locus in Saccharomyces cerevisiae originated by horizontal gene transfer from Wickerhamomyces.  

PubMed

The asparagine degradation pathway in the S288c laboratory strain of Saccharomyces cerevisiae is comprised of genes located at two separate loci. ASP1 is located on chromosome IV and encodes for cytosolic l-asparaginase I, whereas ASP3 contains a gene cluster located on chromosome XII comprised of four identical genes, ASP3-1, ASP3-2, ASP3-3, and ASP3-4, which encode for cell wall-associated l-asparaginase II. Interestingly, the ASP3 locus appears to be only present, in variable copy number, in S. cerevisiae strains isolated from laboratory or industrial environments and is completely absent from the genomes of 128 diverse fungal species. Investigation of the evolutionary history of ASP3 across these 128 genomes as well as across the genomes of 43 S. cerevisiae strains shows that ASP3 likely arose in a S. cerevisiae strain via horizontal gene transfer (HGT) from, or a close relative of, the wine yeast Wickerhamomyces anomalus, which co-occurs with S. cerevisiae in several biotechnological processes. Thus, because the ASP3 present in the S288c laboratory strain of S. cerevisiae is induced in response to nitrogen starvation, its acquisition may have aided yeast adaptation to artificial environments. Our finding that the ASP3 locus in S. cerevisiae originated via HGT further highlights the importance of gene sharing between yeasts in the evolution of their remarkable metabolic diversity. PMID:22776361

League, Garrett P; Slot, Jason C; Rokas, Antonis

2012-11-01

226

DNA assembler method for construction of zeaxanthin-producing strains of Saccharomyces cerevisiae  

PubMed Central

Summary DNA assembler enables design and rapid construction of biochemical pathways in a one-step fashion by exploitation of the in vivo homologous recombination mechanism in Saccharomyces cerevisiae. It has many applications in pathway engineering, metabolic engineering, combinatorial biology, and synthetic biology. Here we use the zeaxanthin biosynthetic pathway as an example to describe the key steps in the construction of pathways containing multiple genes using the DNA assembler approach. Methods for the construction of the clones, S. cerevisiae transformation, and zeaxanthin production and detection are shown. PMID:22711131

Shao, Zengyi; Luo, Yunzi; Zhao, Huimin

2015-01-01

227

Characterization of the metabolic shift between oxidative and fermentative growth in Saccharomyces cerevisiae by comparative 13C flux analysis  

Microsoft Academic Search

BACKGROUND: One of the most fascinating properties of the biotechnologically important organism Saccharomyces cerevisiae is its ability to perform simultaneous respiration and fermentation at high growth rate even under fully aerobic conditions. In the present work, this Crabtree effect called phenomenon was investigated in detail by comparative 13C metabolic flux analysis of S. cerevisiae growing under purely oxidative, respiro-fermentative and

Oliver Frick; Christoph Wittmann

2005-01-01

228

Tomato QM-Like Protein Protects Saccharomyces cerevisiae Cells against Oxidative Stress by Regulating Intracellular Proline Levels  

Microsoft Academic Search

Exogenous proline can protect cells of Saccharomyces cerevisiae from oxidative stress. We altered intracel- lular proline levels by overexpressing the proline dehydrogenase gene (PUT1 )o fS. cerevisiae. Put1p performs the first enzymatic step of proline degradation in S. cerevisiae. Overexpression of Put1p results in low proline levels and hypersensitivity to oxidants, such as hydrogen peroxide and paraquat. A put1-disrupted yeast

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

2006-01-01

229

Selection of optimum expression system for production of kringle fragment of human apolipoprotein(a) in Saccharomyces cerevisiae  

Microsoft Academic Search

RecombinantSaccharomyces cerevisiae expression systems were developed to produce a novel human anti-angiogenic protein called LK8, an 86 amino-acid kringle fragment\\u000a protein with three disulfide linkages. Galactose-inducible LK8 expression plasmid was constructed, and LK8 production levels\\u000a by fourS. cerevisiae strains were compared in order to select an optimal host strain.S. cerevisiae 2805 was the most efficient among the strains tested. Elevating

Kwang-Hyun Cha; Myoung-Dong Kim; Tae-Hee Lee; Hyung-Kweon Lim; Kyung-Hwan Jung; Jin-Ho Seo

2004-01-01

230

Crystallization and Preliminary X-ray Diffraction Analysis of motif N from Saccharomyces cerevisiae Dbf4  

SciTech Connect

The Cdc7-Dbf4 complex plays an instrumental role in the initiation of DNA replication and is a target of replication-checkpoint responses in Saccharomyces cerevisiae. Cdc7 is a conserved serine/threonine kinase whose activity depends on association with its regulatory subunit, Dbf4. A conserved sequence near the N-terminus of Dbf4 (motif N) is necessary for the interaction of Cdc7-Dbf4 with the checkpoint kinase Rad53. To understand the role of the Cdc7-Dbf4 complex in checkpoint responses, a fragment of Saccharomyces cerevisiae Dbf4 encompassing motif N was isolated, overproduced and crystallized. A complete native data set was collected at 100 K from crystals that diffracted X-rays to 2.75 {angstrom} resolution and structure determination is currently under way.

Matthews, L.; Duong, A; Prasad, A; Duncker, B; Guarne, A

2009-01-01

231

Biodegradation of crude oil by Saccharomyces cerevisiae isolated from fermented zobo (locally fermented beverage in Nigeria).  

PubMed

The increase in demand for crude oil as a source of energy and as a primary raw material for industries has resulted in an increase in its production, transportation and refining, which in turn has resulted in gross pollution of the environment. In this study, Saccharomyces cerevisiae isolated from a commercially prepared local fermented beverage 'zobo' (prepared from Hibiscus flower) was tested to determine its potential to degrade crude oil for a period of 28 days under aerobic condition. The percentage of oil biodegradation was determined using weight loss method and gas chromatography mass spectroscopy (GC/MS) of the residual crude oil after 28 days. At the end of 28 days 49.29% crude oil degradation was recorded. The result suggests the potential of Saccharomyces cerevisiae for bioremediation of oil polluted sites. PMID:24517030

Abioye, O P; Akinsola, R O; Aransiola, S A; Damisa, D

2013-12-15

232

ISOLATION AND CHARACTERIZATION OF MUTATIONS IN THE @TUBULIN GENE OF SACCHAROMYCES CEREVISIAE  

Microsoft Academic Search

Of 173 mutants of Saccharomyces cerevisiae resistant to the antimitotic drug benomyl (BenR), six also conferred cold-sensitivity for growth and three others conferred temperature-sensitivity for growth in the absence of benomyl. All of the benR mutations tested, including the nine conditional-lethal mutations, were shown to be in the same gene. This gene, TUBP, has previously been molecu- larly cloned and

JAMES H. THOMAS; NORMA F. NEFF; DAVID BOTSTEIN

233

Lipidome profiling of Saccharomyces cerevisiae reveals pitching rate-dependent fermentative performance  

Microsoft Academic Search

A high cell density strategy has been used in bioethanol production to shorten the fermentation period. To reveal the molecular\\u000a basis of fermentative behavior in high cell density, the profiling of the phospholipids and sterols of Saccharomyces cerevisiae during fermentation at five different pitching rates (1, 5, 10, 20, and 40 g\\/L) was investigated. Using LC\\/ESI\\/MSn technology, 148 phospholipid species were

Hong-Chi Tian; Jian Zhou; Bin Qiao; Ying Liu; Jin-Mei Xia; Ying-Jin Yuan

2010-01-01

234

Influence of metal ionic characteristics on their biosorption capacity by Saccharomyces cerevisiae  

Microsoft Academic Search

The influence of metal ionic characteristics on their biosorption capacity was analyzed using quantitative structure–activity\\u000a relationships model. The waste biomass of Saccharomyces cerevisiae was used as biosorbent to adsorb 10 kinds of metal ions, and their maximum biosorption capacity (q\\u000a max) was determined by the Langmuir isotherm model. The values of q\\u000a max decreased in the following order (in millimole

Can Chen; Jianlong Wang

2007-01-01

235

The novel nuclear gene DSS1 of Saccharomyces cerevisiae is necessary for mitochondrial biogenesis  

Microsoft Academic Search

A previously unknown nuclear gene DSS-1 from Saccharomyces cerevisiae was cloned and sequenced. The gene was isolated as a multicopy suppressor of a disruption of the SUV-3 gene coding for a DEAD\\/H box protein involved in processing and turnover of mitochondrial transcripts. The DSS-1 gene codes for a 970 amino-acid protein of molecular weight 111 kDa and is necessary for

Aleksandra Dmochowska; Pawel Golik; Piotr P. Stepien

1995-01-01

236

Applications of the Saccharomyces cerevisiae Flp-FRT System in Bacterial Genetics  

Microsoft Academic Search

The Flp-FRT site-specific recombinationsystem from Saccharomyces cerevisiae is a powerful and efficient tool for high-throughput genetic analysis of bacteria in the postgenomic era. This review highlights the features of the Flp-FRT system, describes current bacterial genetic methods incorporating this technology and, finally, suggests potential future uses of this system. In combination with improved allele replacement methods, recyclable FRT mutagenesis cassettes,

Herbert P. Schweizer

2003-01-01

237

A DNA sequence which shows genomic variation in a , alpha and HO strains of Saccharomyces cerevisiae  

Microsoft Academic Search

HindIII digested DNA from various mutant strains of Saccharomyces cerevisiae probed with a 340 by nucleotide sequence in M13mp8 derived from a mouse liver cDNA clone p1581 showed strong hybridization to a 4.1 kb DNA fragment class. This was limited to the DNA of cells of alpha mating type but the fragments concerned apparently do not originate from chromosome III.

N. Jasani Gupta; K. W. Jones

1987-01-01

238

Expression of an Aspergillus niger Phytase Gene (phyA )i n Saccharomyces cerevisiae  

Microsoft Academic Search

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals and reduces phosphorus pollution of animal waste. Our objectives were to express an Aspergillus niger phytase gene (phyA )i nSaccharomyces cerevisiae and to determine the effects of glycosylation on the phytase's activity and thermostability. A 1.4-kb DNA fragment containing the coding region of the phyA gene

YANMING HAN; DAVID B. WILSON; XIN GEN LEI

1999-01-01

239

Spermidine or Spermine is Essential for the Aerobic Growth of Saccharomyces cerevisiae  

Microsoft Academic Search

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

David Balasundaram; Celia White Tabor; Herbert Tabor

1991-01-01

240

Preparation and characterization of Saccharomyces cerevisiae alcohol dehydrogenase immobilized on magnetic nanoparticles  

Microsoft Academic Search

The covalently immobilized of Saccharomyces cerevisiae alcohol dehydrogenase (SCAD) to magnetic Fe3O4 nanoparticles via glutaraldehyde coupling reaction was studied. The magnetic Fe3O4 nanoparticles were prepared by hydrothermal method using H2O2 as an oxidizer. Functionalization of surface-modified magnetic particles was performed by the covalent binding of chitosan onto the surface. The amino functional group on the magnetic Fe3O4-chitosan particles surface and

Gui Yin Li; Ke Long Huang; Yu Ren Jiang; Dong Liang Yang; Ping Ding

2008-01-01

241

Kinetics of adsorption of Saccharomyces cerevisiae mandelated dehydrogenase on magnetic Fe 3O 4–chitosan nanoparticles  

Microsoft Academic Search

The adsorption of Saccharomyces cerevisiae mandelated dehydrogenase (SCMD) protein on the surface-modified magnetic nanoparticles coated with chitosan was studied in a batch adsorption system. Functionalization of surface-modified magnetic particles was performed by the covalent binding of chitosan onto the surface of magnetic Fe3O4 nanoparticles. Characterization of these particles was carried out using FTIR spectra, transmission electron micrography (TEM), X-ray diffraction

Gui-Yin Li; Yu-Ren Jiang; Ke-Long Huang; Ping Ding; Li-Li Yao

2008-01-01

242

Fractionation of Phenolic Compounds Extracted from Propolis and Their Activity in the Yeast Saccharomyces cerevisiae  

PubMed Central

We have here investigated the activities of Slovenian propolis extracts in the yeast Saccharomyces cerevisiae, and identified the phenolic compounds that appear to contribute to these activities. We correlated changes in intracellular oxidation and cellular metabolic energy in these yeasts with the individual fractions of the propolis extracts obtained following solid-phase extraction. The most effective fraction was further investigated according to its phenolic compounds. PMID:23409133

Petelinc, Tanja; Polak, Tomaž; Demšar, Lea; Jamnik, Polona

2013-01-01

243

Alkyl hydroperoxide reductase 1 protects Saccharomyces cerevisiae against metal ion toxicity and glutathione depletion  

Microsoft Academic Search

Alkyl hydroperoxide reductase 1 (Ahp1p) is a thioredoxin peroxidase of the peroxiredoxin family expressed by Saccharomyces cerevisiae. Recently, disruption of the AHP1 gene has shown that the gene is not essential for yeast growth on glucose medium but revealed a high sensitivity of null mutants to organic peroxides, suggesting that Ahp1p is an important enzyme implicated in oxidative stress protection

Nhu Tiên Nguyên-nhu; Bernard Knoops

2002-01-01

244

Eaf3 Regulates the Global Pattern of Histone Acetylation in Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae has a global pattern of histone acetylation in which histone H3 and H4 acetylation levels are lower at protein-coding sequences than at promoter regions. The loss of Eaf3, a subunit of the NuA4 histone acetylase and Rpd3 histone deacetylase complexes, greatly alters the genomic profile of histone acetylation, with the effects on H4 appearing to be more pronounced

Juliet L. Reid; Zarmik Moqtaderi; Kevin Struhl

2004-01-01

245

Comparison of the continuous flotation performances of Saccharomyces cerevisiae LBG H620 and DSM 2155 strains  

Microsoft Academic Search

Saccharomyces cerevisiae LBG H620 and DSM 2155 strains were continuously cultivated under carbon (C)-limited, phosphorus (P)-limited and nitrogen (N)-limited growth conditions. Cell and protein concentrations in feed, foam, and residue as well as the degree of cell recovery and the rate of foaming were measured, and the concentration and enrichment factors were evaluated at different dilution rates (D). The LBG

R. Tybussek; F. Linz; K. Schiigerl; N. Moses; A. J. Léonard; P. G. Rouxhet

1994-01-01

246

A comprehensive analysis of protein-protein interactions in Saccharomyces cerevisiae  

Microsoft Academic Search

Two large-scale yeast two-hybrid screens were undertaken to identify protein-protein interactions between full-length open reading frames predicted from the Saccharomyces cerevisiae genome sequence. In one approach, we constructed a protein array of about 6,000 yeast transformants, with each transformant expressing one of the open reading frames as a fusion to an activation domain. This array was screened by a simple

Peter Uetz; Loic Giot; Gerard Cagney; Traci A. Mansfield; Richard S. Judson; James R. Knight; Daniel Lockshon; Vaibhav Narayan; Maithreyan Srinivasan; Pascale Pochart; Alia Qureshi-Emili; Ying Li; Brian Godwin; Diana Conover; Theodore Kalbfleisch; Govindan Vijayadamodar; Meijia Yang; Mark Johnston; Jonathan M. Rothberg

2000-01-01

247

New amylolytic yeast strains for starch and dextrin fermentation. [Schwanniomyces alluvius, Saccharomyces cerevisiae var. diastaticus  

SciTech Connect

Yeast strains capable of fermenting starch and dextrin to ethanol were isolated from samples collected from Brazilian factories in which cassava flour is produced. Considerable alcohol production was observed for all the strains selected. One strain (DI-10) fermented starch rapidly and secreted 5 times as much amylolytic enzyme than that observed for Schwanniomyces alluvius UCD 54-83. This strain and three other similar isolates were classified as Saccharomyces cerevisiae var. diastaticus by morphological and physiological characteristics and molecular taxonomy.

Laluce, C.; Bertolini, M.C.; Ernandes, J.R. (Universidade Estadual Paulista, Sao Paulo (Brazil)); Martini, A.V.; Martini, A. (Universita de Perugia (Italy))

1988-10-01

248

Modelling the network of cell cycle transcription factors in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

Background  Reverse-engineering regulatory networks is one of the central challenges for computational biology. Many techniques have been\\u000a developed to accomplish this by utilizing transcription factor binding data in conjunction with expression data. Of these\\u000a approaches, several have focused on the reconstruction of the cell cycle regulatory network ofSaccharomyces cerevisiae. The emphasis of these studies has been to model the relationships between

Shawn Cokus; Sherri Rose; David Haynor; Niels Grønbech-Jensen; Matteo Pellegrini

2006-01-01

249

Purification of transmembrane proteins from Saccharomyces cerevisiae for X-ray crystallography  

Microsoft Academic Search

To enhance the quantity and quality of eukaryotic transmembrane proteins (TMPs) available for structure determination by X-ray crystallography, we have optimized protocols for purification of TMPs expressed in the yeast Saccharomyces cerevisiae. We focused on a set of the highest-expressing endogenous yeast TMPs for which there are established biochemical assays. Genes encoding the target TMPs are transferred via ligation-independent cloning

Kathleen M. Clark; Nadia Fedoriw; Katrina Robinson; Sara M. Connelly; Joan Randles; Michael G. Malkowski; George T. DeTitta; Mark E. Dumont

2010-01-01

250

Thi20, a remarkable enzyme from Saccharomyces cerevisiae with dual thiamin biosynthetic and degradation activities  

Microsoft Academic Search

Saccharomyces cerevisiae Thi20 is a fusion protein with homology to Bacillus subtilis ThiD and TenA. The N-terminus of Thi20 has significant sequence homology to B. subtilis ThiD, while the C-terminus has homology to B. subtilis TenA. Incubation of Thi20 with thiamin reveals that it has thiaminase II activity, in addition, incubation of Thi20 with HMP (4-amino-2-methyl-5-hydroxymethylpyrimidine) and ATP reveals that

Amy L. Haas; Nathan P. Laun; Tadhg P. Begley

2005-01-01

251

Recent progress in understanding thiamin biosynthesis and its genetic regulation in Saccharomyces cerevisiae  

Microsoft Academic Search

The yeast Saccharomyces cerevisiae is able to synthesize thiamin pyrophosphate (TPP) de novo, which involves the independent formation of two ring structures, 2-methyl-4-amino-5-hydroxymethylpyrimidine and 4-methyl-5-?-hydroxyethylthiazole, in the early steps. In addition, this organism can efficiently utilize thiamin from the extracellular environment to produce TPP. Nineteen genes involved in the synthesis of TPP and the utilization of thiamin (THI genes) have

Kazuto Nosaka

2006-01-01

252

AZF1 Is a Glucose-Dependent Positive Regulator of CLN3 Transcription in Saccharomyces cerevisiae  

Microsoft Academic Search

Transcription of the CLN3 G1 cyclin in Saccharomyces cerevisiae is positively regulated by glucose in a process that involves a set of DNA elements with the sequence AAGAAAAA (A2GA5). To identify proteins that interact with these elements, we used a 1-hybrid approach, which yielded a nuclear zinc finger protein previously iden- tified as Azf1. Gel shift and chromatin immunoprecipitation experiments

Laura L. Newcomb; Duane D. Hall; Warren Heideman

2002-01-01

253

Ethanol production by Saccharomyces cerevisiae immobilized in hollow-fiber membrane bioreactors  

Microsoft Academic Search

Saccharomyces cerevisiae ATCC 4126 was grown within the macroporous matrix of asymmetric-walled polysulfone hollow-fiber membranes and on the exterior surfaces of isotropic-walled polypropylene hollow-fiber membranes. Nutrients were supplied and products were removed by single-pass perfusion of the fiber lumens. Growth of yeast cells within the macrovoids of the asymmetric-walled membranes attained densities of greater than 10 to the power of

D. S. Inloes; D. P. Taylor; S. N. Cohen; A. S. Michaels; C. S. Robertson

1983-01-01

254

Appearance of a new species of ribonucleic acid during sporulation in Saccharomyces cerevisiae.  

PubMed

In the course of study on ribonucleic acid (RNA) metabolism during sporulation in Saccharomyces cerevisiae, a new species of RNA (20S) was observed in sporulating cells by polyacrylamide gel electrophoresis. The relative content of this RNA to total RNA increased linearly early in sporulation. Labeled adenine was preferentially incorporated into 20S RNA during the early stages of sporulation. The correlation between the physiological and genetic control of sporulation and the synthesis of 20S RNA are discussed. PMID:5547990

Kadowaki, K; Halvorson, H O

1971-03-01

255

Appearance of a New Species of Ribonucleic Acid During Sporulation in Saccharomyces cerevisiae  

PubMed Central

In the course of study on ribonucleic acid (RNA) metabolism during sporulation in Saccharomyces cerevisiae, a new species of RNA (20S) was observed in sporulating cells by polyacrylamide gel electrophoresis. The relative content of this RNA to total RNA increased linearly early in sporulation. Labeled adenine was preferentially incorporated into 20S RNA during the early stages of sporulation. The correlation between the physiological and genetic control of sporulation and the synthesis of 20S RNA are discussed. Images PMID:5547990

Kadowaki, Kiyoshi; Halvorson, H. O.

1971-01-01

256

New Potential Cell Wall Glucanases of Saccharomyces cerevisiae and Their Involvement in Mating  

Microsoft Academic Search

Biotinylation of intact Saccharomyces cerevisiae cells with a nonpermeant reagent (Sulfo-NHS-LC-Biotin) al- lowed the identification of seven cell wall proteins that were released from intact cells by dithiothreitol (DTT). By N-terminal sequencing, three of these proteins were identified as the known proteins b-exoglucanase 1 (Exg1p), b-endoglucanase (Bgl2p), and chitinase (Cts1p). One protein was related to the PIR protein family, whereas

CORINNA CAPPELLARO; VLADIMIR MRSA; WIDMAR TANNER

1998-01-01

257

An in vitro assay for (1?6)-?-D-glucan synthesis in Saccharomyces cerevisiae  

Microsoft Academic Search

?-D-glucan is a key cell wall component of Saccharomyces cerevisiae and Candida albicans. Many genes are known to affect the levels or structure of this glucan, but their roles and a molecular description of the synthesis of (1 ? 6)- ?-D-glucan remain to be established and a method to measure (1 ? 6)-?-D-glucan synthase activity in vitro would provide an

Edwin Vink; Roberto J. Rodriguez-Suarez; Manon G ´ erard-Vincent; Juan Carlos Ribas; Hans de Nobel; Herman van den Ende; Angel Dur ´ an; M. Klis; Howard Bussey

258

An in vitro assay for (1-->6)-beta-D-glucan synthesis in Saccharomyces cerevisiae  

Microsoft Academic Search

(1 --> 6)-beta-D-glucan is a key cell wall component of Saccharomyces cerevisiae and Candida albicans. Many genes are known to affect the levels or structure of this glucan, but their roles and a molecular description of the synthesis of (1 --> 6)-beta-D-glucan remain to be established and a method to measure (1 --> 6)-beta-D-glucan synthase activity in vitro would provide

E. Vink; R. J. Rodriguez-Suarez; M. Gerard-Vincent; J. C. Ribas; Nobel de J. G; Ende van den H; A. Duran; F. M. Klis; H. Bussey

2004-01-01

259

Effects of a Saccharomyces cerevisiae Culture on Ruminal Bacteria that Utilize Lactate and Digest Cellulose  

Microsoft Academic Search

The objective of this study was to determine the effects of a yeast ( Saccharomyces cerevisiae) culture on lactate utilization and cellulose digestion by rumi- nal bacteria. Growth of Selenomonas ruminantium HD4 in medium that contained 5 g\\/L of DL-lactate, Trypticase, and yeast extract was stimulated 7 and 15% by 1 and 5% (vol\\/vol) yeast culture filtrate, respectively. The 1

E. S. Callaway; S. A. Martin

1997-01-01

260

Effect of low pH on organization of the actin cytoskeleton in Saccharomyces cerevisiae  

Microsoft Academic Search

Cell growth in the yeast Saccharomyces cerevisiae depends on polarization of the actin cytoskeleton. In this study, we investigated how the cell regulates the distribution of actin in response to low pH conditions, focusing on the role of mitogen-activated protein kinases, Hog1 and Slt2. Changing the extracellular pH from 6.0 to 3.0 caused a transient depolarization of the actin cytoskeleton.

M. Motizuki; S. Yokota; K. Tsurugi

2008-01-01

261

Accumulation of 2'-O-Methylguanosine Deficient tRNATrp in Tryptophan Limited Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae synthesizes one major tryptophan transfer ribonucleic acid (tRNATrp) species (isoacceptor A) carrying characteristic base modifications. Under tryptophan limited growth conditions wild-type strain X2180-1A exhibited a second important tRNATrp species (isoacceptor B). The total amount of tRNATrP, approximately 2.5 pmol (mg dry wt)-l, stayed essentially constant during amino acid shift-down experiments. The amount of isoacceptor B relative to total

PETER STAHELI; PAUL F. AGRIS; PETER NIEDERBERGER; CHARLES W. GEHRKE; R. Hutter

1982-01-01

262

Computer-Assisted Nonlinear Regression Analysis of the Multicomponent Glucose Uptake Kinetics ofSaccharomyces cerevisiae  

Microsoft Academic Search

The kinetics of glucose uptake in Saccharomyces cerevisiae are complex. An Eadie-Hofstee (rate of uptake versus rate of uptake over substrate concentration) plot of glucose uptake shows a nonlinear form typical of amulticomponentsystem.Thenatureoftheconstituentcomponentsisasubjectofdebate.Ithasrecentlybeen suggested that this nonlinearity is due to either a single saturable component together with free diffusion of glucose or a single constitutive component with a variable Km,

DAVID M. COONS; ROGER B. BOULTON; ANDLINDA F. BISSON

1995-01-01

263

Ontology-based cross-species integration and analysis of Saccharomyces cerevisiae phenotypes  

E-print Network

)  budding (APO:0000024): absent (APO:0000005)  cell cycle progression (APO:0000253): arrested (APO:0000250) To formalize these phenotypes, we first identify the entity and the quality that is affected in a phenotype. For example, Heat sensitivity (APO... saccharomyces cerevisiae genome-wide mutant screen for sensitivity to 2,4-diacetylphloroglucinol, an antibiotic produced by pseudomonas fluorescens. Appl Environ Microbiol 2010, 77:1770-1776. 3. Bell G: Experimental genomics of fitness in yeast. Proceedings...

Gkoutos, Georgios V; Hoehndorf, Robert

2012-09-21

264

The complete amino acid sequence of copper, zinc superoxide dismutase from Saccharomyces cerevisiae  

Microsoft Academic Search

The amino acid sequence of the copper zinc superoxide dismutase from Saccharomyces cerevisiae has been determined by automated\\u000a Edman degradation. Peptides were obtained from cyanogen bromide cleavage, Staphylococcus aureus V8 protease digestion, tryptic\\u000a and chymotryptic digests of the citraconylated reduced and carboxymethylated enzyme, and by further fragmentation of selected\\u000a peptides with trypsin. From the alignment of these peptides and the

Jack T. Johansen; Carsten Overballe-Petersen; Brian Martin; Villy Hasemann; Ib Svendsen

1979-01-01

265

Backbone and side chain NMR assignments for the ribosome assembly factor Nop6 from Saccharomyces cerevisiae.  

PubMed

The Saccharomyces cerevisiae Nop6 protein is involved in the maturation of the small ribosomal subunit. It contains a central RNA binding domain and a predicted C-terminal coiled-coil domain. Here we report the almost complete (>90%) (1)H,(13)C,(15)N backbone and side chain NMR assignment of a 15 kDa Nop6 construct comprising the RNA binding and coiled-coil domains. PMID:23921755

Wurm, Jan Philip; Lioutikov, Anatoli; Kötter, Peter; Entian, Karl-Dieter; Wöhnert, Jens

2014-10-01

266

Protein expression during lag phase and growth initiation in Saccharomyces cerevisiae  

Microsoft Academic Search

In order to obtain a better understanding of the biochemical events taking place in Saccharomyces cerevisiae during the lag phase, the proteins expressed during the first hours after inoculation were investigated by two-dimensional (2-D) gel electrophoresis and compared to those expressed in late respiratory growth phase. The studies were performed on a haploid strain (S288C) grown in defined minimal medium.

Jeanette Brejning; Lene Jespersen

2002-01-01

267

Fungicidal Action of Aureobasidin A, a Cyclic Depsipeptide Antifungal Antibiotic, againstSaccharomyces cerevisiae  

Microsoft Academic Search

Aureobasidin A, an antifungal antibiotic inhibiting a wide range of pathogenic fungi, is lethal for growing cells of susceptible fungi. We did cytological studies on the mechanism of its fungicidal action against Saccharomyces cerevisiae. When cultures were treated with 5.0 mg of aureobasidin A per ml, the numbers of viablecellsstartedtodecreaseafter2to3hofincubation,andmostcellshadlostviabilityafter5to6h.When cell death in the treated cultures began, amino acids released

MASAHIRO ENDO; KAZUTOH TAKESAKO; IKUNOSHIN KATO; ANDHIDEYO YAMAGUCHI

1997-01-01

268

Cysteine125 is the catalytic residue of Saccharomyces cerevisiae free methionine- R-sulfoxide reductase  

Microsoft Academic Search

Free methionine-R-sulfoxide reductase (fRMsr) is a new type of methionine sulfoxide reductase that catalyzes the reduction of free methionine-R-sulfoxide to methionine. This enzyme cannot reduce oxidized methionine residues in proteins. While three Cys residues, Cys-91, Cys-101 and Cys-125, have been demonstrated to be involved in the catalysis by Saccharomyces cerevisiae fRMsr, their specific functions have not been fully established. In

Geun-Hee Kwak; Moon-Jung Kim; Hwa-Young Kim

2010-01-01

269

Expression of fungal phytase on the cell surface of Saccharomyces cerevisiae  

Microsoft Academic Search

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus\\u000a pollution of animal waste. We have engineered the cell surface of the yeast,Saccharomyces cerevisiae by anchoring active fungal phytase on its cell wall, in order to apply it as a dietary supplement containing bioconversional\\u000a functions in animal foods and a whole cell

Ae-Young Mo; Seung-Moon Park; Yun-Sik Kim; Moon-Sik Yang; Dae-Hyuk Kim

2005-01-01

270

The SNFZ, SNFS and SNF6 Genes Are Required for Ty Transcription in Saccharomyces cerevisiae  

Microsoft Academic Search

The Saccharomyces cerevisiae SNF2, SNFS and SNF6 genes were initially identified as genes required for expression of SUC2 and other glucose repressible genes. The Suc- defect in all three of these classes of mutants is suppressed by mutations in the SPT6 gene. Since mutations in SPT6 had also been identified as suppressors of Ty and solo 6 insertion mutations at

Anne M. Happel; Michele S. Swanson; Fred Winston

1991-01-01

271

Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process  

Microsoft Academic Search

In order to identify an optimal aeration strategy for intensifying bio-fuel ethanol production in fermentation processes where growth and production have to be managed simultaneously, we quantified the effect of aeration conditions—oxygen limited vs non limited culture (micro-aerobic vs aerobic culture)—on the dynamic behaviour of Saccharomyces cerevisiae cultivated in very high ethanol performance fed-batch cultures. Fermentation parameters and kinetics were

S. Alfenore; X. Cameleyre; L. Benbadis; C. Bideaux; J.-L. Uribelarrea; G. Goma; C. Molina-Jouve; S. E. Guillouet

2004-01-01

272

Synergistic temperature and ethanol effect on Saccharomyces cerevisiae dynamic behaviour in ethanol bio-fuel production  

Microsoft Academic Search

The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33°C around 120 g l -1 ethanol produced in 30 h with a slight benefit for growth at 30°C and for

A. S. Aldiguier; S. Alfenore; X. Cameleyre; G. Goma; J. L. Uribelarrea; S. E. Guillouet; C. Molina-Jouve

2004-01-01

273

Anti-Saccharomyces cerevisiae autoantibodies in autoimmune diseases: from bread baking to autoimmunity.  

PubMed

Saccharomyces cerevisiae is best known as the baker's and brewer's yeast, but its residual traces are also frequent excipients in some vaccines. Although anti-S. cerevisiae autoantibodies (ASCAs) are considered specific for Crohn's disease, a growing number of studies have detected high levels of ASCAs in patients affected with autoimmune diseases as compared with healthy controls, including antiphospholipid syndrome, systemic lupus erythematosus, type 1 diabetes mellitus, and rheumatoid arthritis. Commensal microorganisms such as Saccharomyces are required for nutrition, proper development of Peyer's aggregated lymphoid tissue, and tissue healing. However, even the commensal nonclassically pathogenic microbiota can trigger autoimmunity when fine regulation of immune tolerance does not work properly. For our purposes, the protein database of the National Center for Biotechnology Information (NCBI) was consulted, comparing Saccharomyces mannan to several molecules with a pathogenetic role in autoimmune diseases. Thanks to the NCBI bioinformation technology tool, several overlaps in molecular structures (50-100 %) were identified when yeast mannan, and the most common autoantigens were compared. The autoantigen U2 snRNP B? was found to conserve a superfamily protein domain that shares 83 % of the S. cerevisiae mannan sequence. Furthermore, ASCAs may be present years before the diagnosis of some associated autoimmune diseases as they were retrospectively found in the preserved blood samples of soldiers who became affected by Crohn's disease years later. Our results strongly suggest that ASCAs' role in clinical practice should be better addressed in order to evaluate their predictive or prognostic relevance. PMID:23292495

Rinaldi, Maurizio; Perricone, Roberto; Blank, Miri; Perricone, Carlo; Shoenfeld, Yehuda

2013-10-01

274

Molecular Characterization of New Natural Hybrids of Saccharomyces cerevisiae and S. kudriavzevii in Brewing? †  

PubMed Central

We analyzed 24 beer strains from different origins by using PCR-restriction fragment length polymorphism analysis of different gene regions, and six new Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrid strains were found. This is the first time that the presence in brewing of this new type of hybrid has been demonstrated. From the comparative molecular analysis of these natural hybrids with respect to those described in wines, it can be concluded that these originated from at least two hybridization events and that some brewing hybrids share a common origin with wine hybrids. Finally, a reduction of the S. kudriavzevii fraction of the hybrid genomes was observed, but this reduction was found to vary among hybrids regardless of the source of isolation. The fact that 25% of the strains analyzed were discovered to be S. cerevisiae × S. kudriavzevii hybrids suggests that an important fraction of brewing strains classified as S. cerevisiae may correspond to hybrids, contributing to the complexity of Saccharomyces diversity in brewing environments. The present study raises new questions about the prevalence of these new hybrids in brewing as well as their contribution to the properties of the final product. PMID:18296532

González, Sara S.; Barrio, Eladio; Querol, Amparo

2008-01-01

275

Chemistry & Biology Structure of Saccharomyces cerevisiae Chitinase 1  

E-print Network

-type chitinases in fungi. A knockout of the cts1 gene in S. cerevisiae resulted in a ``clumping'' pheno- type possesses two chitinase-encoding genes: the plant-type chitinase ScCTS1 [7] with an apparent molecu- lar for sub- strate binding (Figure 1). Gene disruption studies of the bacterial-type chitinase genes in A

van Aalten, Daan

276

Enhancing beta-carotene production in Saccharomyces cerevisiae by metabolic engineering.  

PubMed

Beta-carotene is known to exhibit a number of pharmacological and nutraceutical benefits to human health. Metabolic engineering of beta-carotene biosynthesis in Saccharomyces cerevisiae has been attracting the interest of many researchers. A previous work has shown that S. cerevisiae successfully integrated with phytoene synthase (crtYB) and phytoene desaturase (crtI) from Xanthophyllomyces dendrorhous could produce beta-carotene. In the present study, we achieved around 200% improvement in beta-carotene production in S. cerevisiae through specific site optimization of crtI and crtYB, in which five codons of crtI and eight codons of crtYB were rationally mutated. Furthermore, the effects of the truncated HMG-CoA reductase (tHMG1) from S. cerevisiae and HMG-CoA reductase (mva) from Staphylococcus aureus on the production of beta-carotene in S. cerevisiae were also evaluated. Our results indicated that mva from a prokaryotic organism might be more effective than tHMG1 for beta-carotene production in S. cerevisiae. PMID:23718229

Li, Qian; Sun, Zhiqiang; Li, Jing; Zhang, Yansheng

2013-08-01

277

A protocol for the subcellular fractionation of Saccharomyces cerevisiae using nitrogen cavitation and density gradient centrifugation  

PubMed Central

Most protocols for yeast subcellular fractionation involve the use of mechanical shear forces to lyse the spheroplasts produced by the enzymatic digestion of the Saccharomyces cerevisiae cell wall. These mechanical homogenization procedures often involve the manual use of devices such as the Dounce homogenizer, and so are very operator-dependent and, in consequence, lack reproducibility. Here, we report a highly reproducible method of homogenizing yeast cells based on nitrogen cavitation. This has been optimized to allow efficient release of subcellular compartments that show a high degree of integrity. The protocol remains effective and reproducible across a range of sample volumes and buffer environments. The subsequent separation method, which employs both sucrose and iodixanol density gradients, has been developed to resolve the major membrane-bound compartments of S. cerevisiae. We present an integrated protocol that is fast, facile, robust and efficient and that will enable ‘omics’ studies of the subcellular compartments of S. cerevisiae and other yeasts. PMID:24510422

Wang, Yuchong; Lilley, Kathryn S; Oliver, Stephen G

2014-01-01

278

Improvement of ethanol production by electrochemical redox coupling of Zymomonas mobilis and Saccharomyces cerevisiae.  

PubMed

Zymomonas mobilis was immobilized in a modified graphite felt cathode with neutral red (NR-graphite cathode) and Saccharomyces cerevisiae was cultivated on a platinum plate anode to electrochemically activate ethanol fermentation. Electrochemical redox reaction was induced by 3 approximately 4 volt of electric potential charged to a cathode and an anode. Z. mobilis produced 1.3 approximately 1.5 M of ethanol in the cathode compartment and S. cerevisiae did 1.7 approximately 1.9 M in the anode compartment for 96 hr. The ethanol production by Z. mobilis immobilized in the NR-graphite cathode and S. cerevisiae cultivated on the platinum plate was 1.5 approximately 1.6 times higher than those cultivated in the conventional condition. The electrochemical oxidation potential greatly inhibited ethanol fermentation of Z. mobilis but did not S. cerevisiae. Total soluble protein pattern of Z. mobilis cultivated in the electrochemical oxidation condition was getting simplified in proportion to potential intensity based on SDS-PAGE pattern; however the SDS-PAGE pattern of protein extracted from S. cerevisiae cultivated in both oxidation and reduction condition was not changed. When Z. mobilis culture incubated in the cathode compartment for 24 hr was transferred to S. cerevisiae culture in the anode compartment, 0.8 approximately 0.9 M of ethanol was additionally produced by S. cerevisiae for another 24 hr. Conclusively, total 2.0 approximately 2.1 M of ethanol was produced by the electrochemical redox coupling of Z. mobilis and S. cerevisiae for 48 hr. PMID:20134239

Jeon, Bo Young; Park, Doo Hyun

2010-01-01

279

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

Code of Federal Regulations, 2010 CFR

...brewer's yeast) in human serum or plasma. Detection of S. cerevisiae antibodies may aid in the diagnosis of Crohn's disease. (b) Classification. Class II (special controls). The special control is FDA's “Guidance for...

2010-04-01

280

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

Code of Federal Regulations, 2011 CFR

...brewer's yeast) in human serum or plasma. Detection of S. cerevisiae antibodies may aid in the diagnosis of Crohn's disease. (b) Classification. Class II (special controls). The special control is FDA's “Guidance for...

2011-04-01

281

Screening for Hydrolytic Enzymes Reveals Ayr1p as a Novel Triacylglycerol Lipase in Saccharomyces cerevisiae*  

PubMed Central

Saccharomyces cerevisiae, as well as other eukaryotes, preserves fatty acids and sterols in a biologically inert form, as triacylglycerols and steryl esters. The major triacylglycerol lipases of the yeast S. cerevisiae identified so far are Tgl3p, Tgl4p, and Tgl5p (Athenstaedt, K., and Daum, G. (2003) YMR313c/TGL3 encodes a novel triacylglycerol lipase located in lipid particles of Saccharomyces cerevisiae. J. Biol. Chem. 278, 23317–23323; Athenstaedt, K., and Daum, G. (2005) Tgl4p and Tgl5p, two triacylglycerol lipases of the yeast Saccharomyces cerevisiae, are localized to lipid particles. J. Biol. Chem. 280, 37301–37309). We observed that upon cultivation on oleic acid, triacylglycerol mobilization did not come to a halt in a yeast strain deficient in all currently known triacylglycerol lipases, indicating the presence of additional not yet characterized lipases/esterases. Functional proteome analysis using lipase and esterase inhibitors revealed a subset of candidate genes for yet unknown hydrolytic enzymes on peroxisomes and lipid droplets. Based on the conserved GXSXG lipase motif, putative functions, and subcellular localizations, a selected number of candidates were characterized by enzyme assays in vitro, gene expression analysis, non-polar lipid analysis, and in vivo triacylglycerol mobilization assays. These investigations led to the identification of Ayr1p as a novel triacylglycerol lipase of yeast lipid droplets and confirmed the hydrolytic potential of the peroxisomal Lpx1p in vivo. Based on these results, we discuss a possible link between lipid storage, lipid mobilization, and peroxisomal utilization of fatty acids as a carbon source. PMID:24187129

Ploier, Birgit; Scharwey, Melanie; Koch, Barbara; Schmidt, Claudia; Schatte, Jessica; Rechberger, Gerald; Kollroser, Manfred; Hermetter, Albin; Daum, Günther

2013-01-01

282

Transformation of Saccharomyces cerevisiae and Schizosaccharomyces pombe with linear plasmids containing 2 micron sequences.  

PubMed Central

Linear plasmids were constructed by adding telomeres prepared from Tetrahymena pyriformis rDNA to a circular hybrid Escherichia coli-yeast vector and transforming Saccharomyces cerevisiae. The parental vector contained the entire 2 mu yeast circle and the LEU gene from S. cerevisiae. Three transformed clones were shown to contain linear plasmids which were characterized by restriction analysis and shown to be rearranged versions of the desired linear plasmids. The plasmids obtained were imperfect palindromes: part of the parental vector was present in duplicated form, part as unique sequences and part was absent. The sequences that had been lost included a large portion of the 2 mu circle. The telomeres were approximately 450 bp longer than those of T. pyriformis. DNA prepared from transformed S. cerevisiae clones was used to transform Schizosaccharomyces pombe. The transformed S. pombe clones contained linear plasmids identical in structure to their linear parents in S. cerevisiae. No structural re-arrangements or integration into S. pombe was observed. Little or no telomere growth had occurred after transfer from S. cerevisiae to S. pombe. A model is proposed to explain the genesis of the plasmids. Images Fig. 1. Fig. 2. Fig. 4. PMID:3896773

Guerrini, A M; Ascenzioni, F; Tribioli, C; Donini, P

1985-01-01

283

Candida glabrata environmental stress response involves Saccharomyces cerevisiae Msn2/4 orthologous transcription factors.  

PubMed

We determined the genome-wide environmental stress response (ESR) expression profile of Candida glabrata, a human pathogen related to Saccharomyces cerevisiae. Despite different habitats, C. glabrata, S. cerevisiae, Schizosaccharomyces pombe and Candida albicans have a qualitatively similar ESR. We investigate the function of the C. glabrata syntenic orthologues to the ESR transcription factor Msn2. The C. glabrata orthologues CgMsn2 and CgMsn4 contain a motif previously referred to as HD1 (homology domain 1) also present in Msn2 orthologues from fungi closely related to S. cerevisiae. We show that regions including this motif confer stress-regulated intracellular localization when expressed in S. cerevisiae. Site-directed mutagenesis confirms that nuclear export of CgMsn2 in C. glabrata requires an intact HD1. Transcript profiles of CgMsn2/4 mutants and CgMsn2 overexpression strains show that they regulate a part of the CgESR. CgMsn2 complements a S. cerevisiae msn2 null mutant and in stressed C. glabrata cells, rapidly translocates from the cytosol to the nucleus. CgMsn2 is required for full resistance against severe osmotic stress and rapid and full induction of trehalose synthesis genes (TPS1, TPS2). Constitutive activation of CgMsn2 is detrimental for C. glabrata. These results establish an Msn2-regulated general stress response in C. glabrata. PMID:18547390

Roetzer, Andreas; Gregori, Christa; Jennings, Ann Marie; Quintin, Jessica; Ferrandon, Dominique; Butler, Geraldine; Kuchler, Karl; Ammerer, Gustav; Schüller, Christoph

2008-08-01

284

Candida glabrata environmental stress response involves Saccharomyces cerevisiae Msn2/4 orthologous transcription factors  

PubMed Central

We determined the genome-wide environmental stress response (ESR) expression profile of Candida glabrata, a human pathogen related to Saccharomyces cerevisiae. Despite different habitats, C. glabrata, S. cerevisiae, Schizosaccharomyces pombe and Candida albicans have a qualitatively similar ESR. We investigate the function of the C. glabrata syntenic orthologues to the ESR transcription factor Msn2. The C. glabrata orthologues CgMsn2 and CgMsn4 contain a motif previously referred to as HD1 (homology domain 1) also present in Msn2 orthologues from fungi closely related to S. cerevisiae. We show that regions including this motif confer stress-regulated intracellular localization when expressed in S. cerevisiae. Site-directed mutagenesis confirms that nuclear export of CgMsn2 in C. glabrata requires an intact HD1. Transcript profiles of CgMsn2/4 mutants and CgMsn2 overexpression strains show that they regulate a part of the CgESR. CgMsn2 complements a S. cerevisiae msn2 null mutant and in stressed C. glabrata cells, rapidly translocates from the cytosol to the nucleus. CgMsn2 is required for full resistance against severe osmotic stress and rapid and full induction of trehalose synthesis genes (TPS1, TPS2). Constitutive activation of CgMsn2 is detrimental for C. glabrata. These results establish an Msn2-regulated general stress response in C. glabrata. PMID:18547390

Roetzer, Andreas; Gregori, Christa; Jennings, Ann Marie; Quintin, Jessica; Ferrandon, Dominique; Butler, Geraldine; Kuchler, Karl; Ammerer, Gustav; Schüller, Christoph

2008-01-01

285

Saccharomyces cerevisiae: Population Divergence and Resistance to Oxidative Stress in Clinical, Domesticated and Wild Isolates  

PubMed Central

Background Saccharomyces cerevisiae has been associated with human life for millennia in the brewery and bakery. Recently it has been recognized as an emerging opportunistic pathogen. To study the evolutionary history of S. cerevisiae, the origin of clinical isolates and the importance of a virulence-associated trait, population genetics and phenotypic assays have been applied to an ecologically diverse set of 103 strains isolated from clinics, breweries, vineyards, fruits, soil, commercial supplements and insect guts. Methodology/Principal Findings DNA sequence data from five nuclear DNA loci were analyzed for population structure and haplotype distribution. Additionally, all strains were tested for survival of oxidative stress, a trait associated with microbial pathogenicity. DNA sequence analyses identified three genetic subgroups within the recombining S. cerevisiae strains that are associated with ecology, geography and virulence. Shared alleles suggest that the clinical isolates contain genetic contribution from the fruit isolates. Clinical and fruit isolates exhibit high levels of recombination, unlike the genetically homogenous soil isolates in which no recombination was detected. However, clinical and soil isolates were more resistant to oxidative stress than any other population, suggesting a correlation between survival in oxidative stress and yeast pathogenicity. Conclusions/Significance Population genetic analyses of S. cerevisiae delineated three distinct groups, comprising primarily the (i) human-associated brewery and vineyard strains, (ii) clinical and fruit isolates (iii) and wild soil isolates from eastern U.S. The interactions between S. cerevisiae and humans potentiate yeast evolution and the development of genetically, ecologically and geographically divergent groups. PMID:19390633

Diezmann, Stephanie; Dietrich, Fred S.

2009-01-01

286

Formation of AAV Single Stranded DNA Genome from a Circular Plasmid in Saccharomyces cerevisiae  

PubMed Central

Adeno-associated virus (AAV)-based vectors are promising tools for targeted transfer in gene therapy studies. Many efforts have been accomplished to improve production and purification methods. We thought to develop a simple eukaryotic system allowing AAV replication which could provide an excellent opportunity for studying AAV biology and, more importantly, for AAV vector production. It has been shown that yeast Saccharomyces cerevisiae is able to replicate and form the capsid of many viruses. We investigated the ability of the yeast Saccharomyces cerevisiae to carry out the replication of a recombinant AAV (rAAV). When a plasmid containing a rAAV genome in which the cap gene was replaced with the S. cerevisiae URA3 gene, was co-transformed in yeast with a plasmid expressing Rep68, a significant number of URA3+ clones were scored (more than 30-fold over controls). Molecular analysis of low molecular weight DNA by Southern blotting revealed that single stranded DNA is formed and that the plasmid is entirely replicated. The ssDNA contains the ITRs, URA3 gene and also vector sequences suggesting the presence of two distinct molecules. Its formation was dependent on Rep68 expression and ITR. These data indicate that DNA is not obtained by the canonical AAV replication pathway. PMID:21853137

Cervelli, Tiziana; Backovic, Ana; Galli, Alvaro

2011-01-01

287

An improved map of conserved regulatory sites for Saccharomyces cerevisiae  

PubMed Central

Background The regulatory map of a genome consists of the binding sites for proteins that determine the transcription of nearby genes. An initial regulatory map for S. cerevisiae was recently published using six motif discovery programs to analyze genome-wide chromatin immunoprecipitation data for 203 transcription factors. The programs were used to identify sequence motifs that were likely to correspond to the DNA-binding specificity of the immunoprecipitated proteins. We report improved versions of two conservation-based motif discovery algorithms, PhyloCon and Converge. Using these programs, we create a refined regulatory map for S. cerevisiae by reanalyzing the same chromatin immunoprecipitation data. Results Applying the same conservative criteria that were applied in the original study, we find that PhyloCon and Converge each separately discover more known specificities than the combination of all six programs in the previous study. Combining the results of PhyloCon and Converge, we discover significant sequence motifs for 36 transcription factors that were previously missed. The new set of motifs identifies 636 more regulatory interactions than the previous one. The new network contains 28% more regulatory interactions among transcription factors, evidence of greater cross-talk between regulators. Conclusion Combining two complementary computational strategies for conservation-based motif discovery improves the ability to identify the specificity of transcriptional regulators from genome-wide chromatin immunoprecipitation data. The increased sensitivity of these methods significantly expands the map of yeast regulatory sites without the need to alter any of the thresholds for statistical significance. The new map of regulatory sites reveals a more elaborate and complex view of the yeast genetic regulatory network than was observed previously. PMID:16522208

MacIsaac, Kenzie D; Wang, Ting; Gordon, D Benjamin; Gifford, David K; Stormo, Gary D; Fraenkel, Ernest

2006-01-01

288

Variation in Crossover Frequencies Perturb Crossover Assurance Without Affecting Meiotic Chromosome Segregation in Saccharomyces cerevisiae.  

PubMed

The segregation of homologous chromosomes during the Meiosis I division requires an obligate crossover per homolog pair (crossover assurance). In Saccharomyces cerevisiae and mammals, Msh4 and Msh5 proteins stabilize Holliday junctions and its progenitors to facilitate crossing over. Saccharomyces cerevisiae msh4/5 hypomorphs were identified recently that reduce crossover levels up to two-fold at specific loci on chromosomes VII, VIII and XV without affecting homolog segregation. We use the msh4-R676W hypomorph to ask if the obligate crossover is insulated from variation in crossover frequencies, using a Saccharomyces cerevisiae S288c/YJM789 hybrid to map recombination genome wide. The msh4-R676W hypomorph made on average 64 crossovers per meiosis compared to 94 made in wild type and 49 in msh4? mutant confirming the defect seen at individual loci on a genome wide scale. Crossover reductions in msh4-R676W and msh4? were significant across chromosomes regardless of size, unlike previous observations made at specific loci. The msh4-R676W hypomorph showed reduced crossover interference. Although crossover reduction in msh4-R676W is modest, 42% of the four viable spore tetrads showed non-exchange chromosomes. These results, along with modeling of crossover distribution, suggest the significant reduction in crossovers across chromosomes and the loss of interference compromises the obligate crossover in the msh4 hypomorph. The high spore viability of the msh4 hypomorph is maintained by efficient segregation of the natural non-exchange chromosomes. Our results suggest variation in crossover frequencies can compromise the obligate crossover and also support a mechanistic role for interference in obligate crossover formation. PMID:25467183

Krishnaprasad, Gurukripa Nandanan; Anand, Mayakonda Thippeswamy; Lin, Gen; Tekkedil, Manu M; Steinmetz, Lars M; Nishant, Koodali Thazath

2014-12-01

289

Lead sulfide nanoparticles increase cell wall chitin content and induce apoptosis in Saccharomyces cerevisiae.  

PubMed

Although there have been numerous studies on bacterial toxicity, the cytotoxicity of nanoparticles toward fungi remains poorly understood. We investigated the toxicity of various sizes of lead sulfide particles against the important model fungus, Saccharomyces cerevisiae. The smallest particle exerted the highest toxicity, inhibiting cell growth and decreasing cell viability, likely reflecting reduced sedimentation and persistent cell wall attack. In response to cell wall stress, S. cerevisiae showed an increase in the cell wall chitin content and the overexpression of FKS2 and PRM5, two genes of the cell wall integrity signaling pathway. Cell wall stress increased the concentration of intracellular reactive oxygen species, leading to mitochondrial dysfunction and cell apoptosis. The contribution of dissolved lead ions to the overall toxicity was negligible. These findings provide the first demonstration of the physiological protective response of a fungus toward nanoparticles, thereby contributing useful information to the assessment of the environmental impact of metal nanoparticles. PMID:24704549

Sun, Meiqing; Yu, Qilin; Hu, Mengyuan; Hao, Zhenwei; Zhang, Chengdong; Li, Mingchun

2014-05-30

290

The Bioconversion of Red Ginseng Ethanol Extract into Compound K by Saccharomyces cerevisiae HJ-014  

PubMed Central

A ?-glucosidase producing yeast strain was isolated from Korean traditional rice wine. Based on the sequence of the YCL008c gene and analysis of the fatty acid composition, the isolate was identified as Saccharomyces cerevisiae strain HJ-014. S. cerevisiae HJ-014 produced ginsenoside Rd, F2, and compound K from the ethanol extract of red ginseng. The production was increased by shaking culture, where the bioconversion efficiency was increased 2-fold compared to standing culture. The production of ginsenoside F2 and compound K was time-dependent and thought to proceed by the transformation pathway of: red ginseng extract?Rd?F2?compound K. The optimum incubation time and concentration of red ginseng extract for the production of compound K was 96 hr and 4.5% (w/v), respectively. PMID:25346602

Choi, Hak Joo; Kim, Eun A; Kim, Dong Hee

2014-01-01

291

Saccharomyces cerevisiae: a potential stereospecific reduction tool for biotransformation of mono- and sesquiterpenoids.  

PubMed

Terpenes and terpenoids are among the key impact substances in the food and fragrance industries. Equipped with pharmacological properties and applications as ideal precursors for the biotechnological production of natural aroma chemicals, interests in these compounds have been escalating. Hence, the syntheses of new derivatives that can show improved properties are often called for. Stereoselective biotransformation offers several benefits to increase the rate of production, in terms of both the percentage yield and its enantiomeric excesses. Baker's yeast (Saccharomyces cerevisiae) is broadly used as a whole cell stereospecific reduction biocatalyst, due to its capability in reducing carbonyls and carbon-carbon double bonds, which also extends its functionality as a versatile biocatalyst in terpenoid biotransformation. This review provides some insights on the development and prospects in the reductive biotransformation of monoterpenoids and sesquiterpenoids using S. cerevisiae, with an overview of strategies to overcome the common challenges in large-scale implementation. PMID:20939023

Khor, Guat Kheng; Uzir, Mohamad Hekarl

2011-02-01

292

Aerobic isolation of an ERG24 null mutant of Saccharomyces cerevisiae.  

PubMed Central

The ERG24 gene, encoding the C-14 sterol reductase, has been reported to be essential to the aerobic growth of Saccharomyces cerevisiae. We report here, however, that strains with null mutations in the ERG24 gene can grow on defined synthetic media in aerobic conditions. These sterol mutants produce ignosterol (ergosta-8,14-dienol) as the principal sterol, with no traces of ergosterol. In addition, we mapped the ERG24 gene to chromosome XIV between the MET2 and SEC2 genes. Our results indicate that ignosterol can be a suitable sterol for aerobic growth of S. cerevisiae on synthetic media and that inactivation of ERG24 is only conditionally lethal. PMID:8631695

Crowley, J H; Smith, S J; Leak, F W; Parks, L W

1996-01-01

293

Budding yeast for budding geneticists: a primer on the Saccharomyces cerevisiae model system.  

PubMed

The budding yeast Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of eukaryotic cell biology. This Primer article presents a brief historical perspective on the emergence of this organism as a premier experimental system over the course of the past century. An overview of the central features of the S. cerevisiae genome, including the nature of its genetic elements and general organization, is also provided. Some of the most common experimental tools and resources available to yeast geneticists are presented in a way designed to engage and challenge undergraduate and graduate students eager to learn more about the experimental amenability of budding yeast. Finally, a discussion of several major discoveries derived from yeast studies highlights the far-reaching impact that the yeast system has had and will continue to have on our understanding of a variety of cellular processes relevant to all eukaryotes, including humans. PMID:24807111

Duina, Andrea A; Miller, Mary E; Keeney, Jill B

2014-05-01

294

Metabolic engineering of Saccharomyces cerevisiae ethanol strains PE-2 and CAT-1 for efficient lignocellulosic fermentation.  

PubMed

In this work, Saccharomyces cerevisiae strains PE-2 and CAT-1, commonly used in the Brazilian fuel ethanol industry, were engineered for xylose fermentation, where the first fermented xylose faster than the latter, but also produced considerable amounts of xylitol. An engineered PE-2 strain (MEC1121) efficiently consumed xylose in presence of inhibitors both in synthetic and corn-cob hydrolysates. Interestingly, the S. cerevisiae MEC1121 consumed xylose and glucose simultaneously, while a CEN.PK based strain consumed glucose and xylose sequentially. Deletion of the aldose reductase GRE3 lowered xylitol production to undetectable levels and increased xylose consumption rate which led to higher final ethanol concentrations. Fermentation of corn-cob hydrolysate using this strain, MEC1133, resulted in an ethanol yield of 0.47g/g of total sugars which is 92% of the theoretical yield. PMID:25536512

Romaní, Aloia; Pereira, Filipa; Johansson, Björn; Domingues, Lucília

2015-03-01

295

Screening of Stable G-Protein-Coupled Receptor Variants in Saccharomyces cerevisiae.  

PubMed

G-protein-coupled receptors (GPCRs) are not only the largest protein family, but as a whole, they represent the largest group of therapeutic drug targets. Recent successes in the determination of GPCR structures have relied on the stabilization of receptors to overcome the difficulties in expression and purification. Although a large quantity of purified protein is needed for structural determination, the majority of wild-type GPCRs are too unstable to express and purify on a large scale. Therefore, rapid screening of highly expressed stable receptor "variants" is crucial. It has been demonstrated that fusing green fluorescent protein (GFP) to a target membrane protein facilitates the evaluation of the physical properties of the membrane protein in detergent. Furthermore, the budding yeast Saccharomyces cerevisiae enables rapid construction of an expression vector via its own efficient homologous recombination system. Herein, we describe the protocols for rapid construction and screening of stable GPCR variants using GFP and S. cerevisiae. PMID:25502199

Shiroishi, Mitsunori; Kobayashi, Takuya

2015-01-01

296

The effects of microgravity on induced mutation in Escherichia coli and Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

We examined whether microgravity influences the induced-mutation frequencies through in vivo experiments during space flight aboard the space shuttle Discovery (STS-91). We prepared dried samples of repair-deficient strains and parental strains of Escherichia ( E.) coli and Saccharomyces ( S.) cerevisiae given DNA damage treatment. After culture in space, we measured the induced-mutation frequencies and SOS-responses under microgravity. The experimental findings indicate that almost the same induced-mutation frequencies and SOS-responses of space samples were observed in both strains compared with the ground control samples. It is suggested that microgravity might not influence induced-mutation frequencies and SOS-responses at the stages of DNA replication and/or DNA repair. In addition, we developed a new experimental apparatus for space experiments to culture and freeze stocks of E. coli and S. cerevisiae cells.

Takahashi, A.; Ohnishi, K.; Takahashi, S.; Masukawa, M.; Sekikawa, K.; Amano, T.; Nakano, T.; Nagaoka, S.; Ohnishi, T.

2001-01-01

297

Positive selection of general amino acid permease mutants in Saccharomyces cerevisiae.  

PubMed Central

It was found that D-stereoisomers of natural amino acids inhibit the growth of Saccharomyces cerevisiae cells. Kinetic and genetic evidence showed that d-amino acids enter the cell by the general amino acid permease. Two classes of S. cerevisiae mutants resistant to d-amino acids were isolated. One class of mutants appeared to be defective in the general amino acid permease specified by the gene gap. In the second class, the activity of general amino acid permease was affected by ammonium ions. Mutants of the second class were isolated in a yeast strain with the general amino acid permease insensitive to the presence of ammonium ions in culture media. The mutation affecting the permease, amc, occurred in a locus unlinked to gap. PMID:1089636

Rytka, J

1975-01-01

298

Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid  

PubMed Central

Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications. PMID:23430312

Giannattasio, Sergio; Guaragnella, Nicoletta; Ždralevi?, Maša; Marra, Ersilia

2013-01-01

299

Alternative Splicing of PTC7 in Saccharomyces cerevisiae Determines Protein Localization  

PubMed Central

It is well established that higher eukaryotes use alternative splicing to increase proteome complexity. In contrast, Saccharomyces cerevisiae, a single-cell eukaryote, conducts predominantly regulated splicing through retention of nonfunctional introns. In this article we describe our discovery of a functional intron in the PTC7 (YHR076W) gene that can be alternatively spliced to create two mRNAs that code for distinct proteins. These two proteins localize to different cellular compartments and have distinct cellular roles. The protein translated from the spliced mRNA localizes to the mitochondria and its expression is carbon-source dependent. In comparison, the protein translated from the unspliced mRNA contains a transmembrane domain, localizes to the nuclear envelope, and mediates the toxic effects of Latrunculin A exposure. In conclusion, we identified a definitive example of functional alternative splicing in S. cerevisiae that confers a measurable fitness benefit. PMID:19564484

Juneau, Kara; Nislow, Corey; Davis, Ronald W.

2009-01-01

300

Saccharomyces cerevisiae Rif1 cooperates with MRX-Sae2 in promoting DNA-end resection.  

PubMed

Diverse roles in DNA metabolism have been envisaged for budding yeast and mammalian Rif1. In particular, yeast Rif1 is involved in telomere homeostasis, while its mammalian counterpart participates in the cellular response to DNA double-strand breaks (DSBs). Here, we show that Saccharomyces cerevisiae Rif1 supports cell survival to DNA lesions in the absence of MRX or Sae2. Furthermore, it contributes to the nucleolytic processing (resection) of DSBs. This Rif1-dependent control of DSB resection becomes important for DSB repair by homologous recombination when resection activities are suboptimal. PMID:24692507

Martina, Marina; Bonetti, Diego; Villa, Matteo; Lucchini, Giovanna; Longhese, Maria Pia

2014-06-01

301

Expression of rainbow trout growth hormone cDNA in Saccharomyces cerevisiae.  

PubMed

Rainbow trout growth hormone cDNA was modified by polymerase chain reaction (PCR). The modified cDNA was subcloned into the E. coli-yeast shuttle vector pMA91 under the yeast PGK promoter, and transformed into Saccharomyces cerevisiae Y33 to construct an expression strain Y33 (pMArGH16). The recombinant gene could express the growth hormone peptide (about 3% of the total yeast proteins) in Y33 (pMArGH16). The expression product was used as a supplement to feed Tilapia fingerlings. The result showed that the recombinant fish GH could significantly enhance the growth of Tilapia fingerlings. PMID:11037946

Jin, M; Junjie, B; Xinhui, L; Jianren, L; Qing, J; Hongjun, Z

1999-01-01

302

Model-guided identification of gene deletion targets for metabolic engineering in Saccharomyces cerevisiae.  

PubMed

Identification of metabolic engineering strategies for rerouting intracellular fluxes towards a desired product is often a challenging task owing to the topological and regulatory complexity of metabolic networks. Genome-scale metabolic models help tackling this complexity through systematic consideration of mass balance and reaction directionality constraints over the entire network. Here, we describe how genome-scale metabolic models can be used for identifying gene deletion targets leading to increased production of the desired product. Vanillin production in Saccharomyces cerevisiae is used as a case study throughout this chapter. PMID:24744040

Brochado, Ana Rita; Patil, Kiran Raosaheb

2014-01-01

303

Nature of Ribonucleic Acid Synthesis During Early Sporulation in Saccharomyces cerevisiae  

PubMed Central

Phosphate uptake in sporulating cultures of Saccharomyces cerevisiae has been found to occur approximately 2 h after the transfer to sporulation medium. Early ribonucleic acid synthesis begins at approximately 4 h and continues to 8 h. Incorporation of phosphate into acid-extractable precursor pools parallels phosphate uptake. In triple-labeling experiments it was observed that the breakdown of vegetatively synthesized ribonucleic acid is not a significant source of precursors for ribonucleic acid synthesis during sporulation. The majority of the ribonucleic acid made in a 10-min period during sporulation does not migrate on gels with precursor or mature ribosomal ribonucleic acid. PMID:4616951

Chaffin, W. L.; Sogin, S. J.; Halvorson, H. O.

1974-01-01

304

A Highly Tunable System for the Simultaneous Expression of Multiple Enzymes in Saccharomyces cerevisiae.  

PubMed

Control of the expression levels of multiple enzymes in transgenic yeasts is essential for the effective production of complex molecules through fermentation. Here, we propose a tunable strategy for the control of expression levels based on the design of terminator regions and other gene-expression control elements in Saccharomyces cerevisiae. Our genome-integrated system, which is capable of producing high expression levels over a wide dynamic range, will broadly enable metabolic engineering and synthetic biology. We demonstrated that the activities of multiple cellulases and the production of ethanol were doubled in a transgenic yeast constructed with our system compared with those achieved with a standard expression system. PMID:24927017

Ito, Yoichiro; Yamanishi, Mamoru; Ikeuchi, Akinori; Matsuyama, Takashi

2015-01-16

305

High-resolution analysis of condition-specific regulatory modules in Saccharomyces cerevisiae  

PubMed Central

We present an approach for identifying condition-specific regulatory modules by using separate units of gene expression profiles along with ChIP-chip and motif data from Saccharomyces cerevisiae. By investigating the unique and common features of the obtained condition-specific modules, we detected several important properties of transcriptional network reorganization. Our approach reveals the functionally distinct coregulated submodules embedded in a coexpressed gene module and provides an effective method for identifying various condition-specific regulatory events at high resolution. PMID:18171483

Lee, Hun-Goo; Lee, Hyo-Soo; Jeon, Sang-Hoon; Chung, Tae-Hoon; Lim, Young-Sung; Huh, Won-Ki

2008-01-01

306

[Geothermal water as part of culture medium and morpho-physiological properties of Saccharomyces cerevisiae].  

PubMed

Morphophysiological changes in Saccharomyces cerevisiae gamma-503 cells cultivated in nutrient media containing geothermal water as a source of mineral substances were studied. The optimal mineralization of the medium was found to be 4.0 g/l, supplemented with 2.6 g/l (NH4)2HPO4. These conditions provided active growth and development of the culture with high yields of the biomass and the maximal enzymatic activity. Differences in cellular structures at certain stages of metabolism were demonstrated. PMID:10496008

Abramov, Sh A; Kotenko, S Ts; Khalilova, E A; Kisrieva, Iu S

1999-01-01

307

The pentafunctional arom enzyme of Saccharomyces cerevisiae is a mosaic of monofunctional domains.  

PubMed Central

The nucleotide sequence of the Saccharomyces cerevisiae ARO1 gene which encodes the arom multifunctional enzyme has been determined. The protein sequence deduced for the pentafunctional arom polypeptide is 1588 amino acids in length and has a calculated Mr of 174555. Functional regions within the polypeptide chain have been identified by comparison with the sequences of the five monofunctional Escherichia coli enzymes whose activities correspond with those of the arom multifunctional enzyme. The observed homologies demonstrate that the arom polypeptide is a mosaic of functional domains and are consistent with the hypothesis that the ARO1 gene evolved by the linking of ancestral E. coli-like genes. PMID:2825635

Duncan, K; Edwards, R M; Coggins, J R

1987-01-01

308

Transcript characterisation, gene disruption and nucleotide sequence of the Saccharomyces cerevisiae WH12 gene.  

PubMed

WH12 is a gene which plays a prominent role in regulating growth and proliferation in Saccharomyces cerevisiae. It is expressed as a 2.0-kb mRNA transcript. Disruption of this transcript in a WH12+ cell results in the mutant phenotype being displayed. The nucleotide sequence of the cloned gene has been determined and found to include a 487-codon long open reading frame coding for a 55.3-kDa protein. The protein showed no extensive homologies to any previously identified protein. The 5' and 3' noncoding regions contained many of the features found in other yeast genes. PMID:3049245

Kelly, D E; Trevethick, J; Mountain, H; Sudbery, P E

1988-06-30

309

Interactions of PRP2 protein with pre-mRNA splicing complexes in Saccharomyces cerevisiae.  

PubMed

PRP2 protein of Saccharomyces cerevisiae is required for the pre-mRNA splicing reaction but not for the early stages of spliceosome assembly. Using anti-PRP2 antibodies we demonstrate that PRP2 protein is associated with spliceosomes prior to, and throughout step 1 of the splicing reaction. Heat-inactivated prp2 protein, by contrast, does not seem to associate with spliceosomes. By elution of electrophoretically distinct spliceosomal complexes from non-denaturing gels we identify the specific complex with which PRP2 initially interacts in the pathway of spliceosome assembly. PMID:2251118

King, D S; Beggs, J D

1990-11-25

310

Mutation of the mitochondrial large ribosomal RNA can provide pentamidine resistance to Saccharomyces cerevisiae.  

PubMed

Pentamidine is used to treat several trypanosomal diseases, as well as opportunistic infection by pathogenic fungi. However, the relevant targets of this drug are unknown. We isolated dominant mutations providing pentamidine resistance to Saccharomyces cerevisiae, one of which was localized to mitochondrial DNA. Next-generation sequencing revealed alteration of a widely conserved base at the peptidyl transferase center of the mitochondrial 21S ribosomal RNA. Our results provide a potential rationale for the toxicity of this drug to patients, and we discuss whether blockade of mitochondrial translation is the mechanism by which pathogenic fungi or protists are killed by pentamidine. PMID:25151477

Ors, S Tomris; Akdo?an, Emel; Dunn, Cory D

2014-08-21

311

Transport-limited fermentation and growth of Saccharomyces cerevisiae and its competitive inhibition  

Microsoft Academic Search

The anaerobic glucose uptake (at 20°, pH 3.5) by resting cells of Saccharomyces cerevisiae followed unidirectional Michaelis-Menten kinetics and was competitively inhibited by l-sorbose; Km and Ki were respectively 5.6×10-4m and 1.8×10-1m; Vmax was 6.5×10-8 moles mg-1 min-1. The aerobic uptake of glucose by resting yeast was also inhibited by l-sorbose but did not follow unidirectional Michaelis-Menten kinetics. Glucose-limited growth

1967-01-01

312

Synergistic temperature and ethanol effect on Saccharomyces cerevisiae dynamic behaviour in ethanol bio-fuel production.  

PubMed

The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33 degrees C around 120 g l(-1) ethanol produced in 30 h with a slight benefit for growth at 30 degrees C and for ethanol production at 33 degrees C. Glycerol formation, enhanced with increasing temperatures, was coupled with growth for all fermentations; whereas, a decoupling phenomenon occurred at 36 and 39 degrees C pointing out a possible role of glycerol in yeast thermal protection. PMID:15098119

Aldiguier, A S; Alfenore, S; Cameleyre, X; Goma, G; Uribelarrea, J L; Guillouet, S E; Molina-Jouve, C

2004-07-01

313

Genomic reconstruction to improve bioethanol and ergosterol production of industrial yeast Saccharomyces cerevisiae.  

PubMed

Baker's yeast (Saccharomyces cerevisiae) is the common yeast used in the fields of bread making, brewing, and bioethanol production. Growth rate, stress tolerance, ethanol titer, and byproducts yields are some of the most important agronomic traits of S. cerevisiae for industrial applications. Here, we developed a novel method of constructing S. cerevisiae strains for co-producing bioethanol and ergosterol. The genome of an industrial S. cerevisiae strain, ZTW1, was first reconstructed through treatment with an antimitotic drug followed by sporulation and hybridization. A total of 140 mutants were selected for ethanol fermentation testing, and a significant positive correlation between ergosterol content and ethanol production was observed. The highest performing mutant, ZG27, produced 7.9 % more ethanol and 43.2 % more ergosterol than ZTW1 at the end of fermentation. Chromosomal karyotyping and proteome analysis of ZG27 and ZTW1 suggested that this breeding strategy caused large-scale genome structural variations and global gene expression diversities in the mutants. Genetic manipulation further demonstrated that the altered expression activity of some genes (such as ERG1, ERG9, and ERG11) involved in ergosterol synthesis partly explained the trait improvement in ZG27. PMID:25475753

Zhang, Ke; Tong, Mengmeng; Gao, Kehui; Di, Yanan; Wang, Pinmei; Zhang, Chunfang; Wu, Xuechang; Zheng, Daoqiong

2015-02-01

314

mRNA structures influencing translation in the yeast Saccharomyces cerevisiae.  

PubMed Central

The mRNA sequence and structures that modify and are required for translation of iso-1-cytochrome c in the yeast Saccharomyces cerevisiae were investigated with sets of CYC1 alleles having alterations in the 5' leader region. Measurements of levels of CYC1 mRNA and iso-1-cytochrome c in strains having single copies of altered alleles with nested deletions led to the conclusion that there is no specific sequence adjacent to the AUG initiator codon required for efficient translation. However, the nucleotides preceding the AUG initiator codon at positions -1 and -3 slightly modified the efficiency of translation to an order of preference similar to that found in higher cells. In contrast to large effects observed in higher eucaryotes, the magnitude of this AUG context effect in S. cerevisiae was only two- to threefold. Furthermore, introduction of hairpin structures in the vicinity of the AUG initiator codon inhibited translation, with the degree of inhibition related to the stability and proximity of the hairpin. These results with S. cerevisiae and published findings on other organisms suggest that translation in S. cerevisiae is more sensitive to secondary structures than is translation in higher eucaryotes. Images PMID:2837649

Baim, S B; Sherman, F

1988-01-01

315

Phenotypic Landscape of Saccharomyces cerevisiae during Wine Fermentation: Evidence for Origin-Dependent Metabolic Traits  

PubMed Central

The species Saccharomyces cerevisiae includes natural strains, clinical isolates, and a large number of strains used in human activities. The aim of this work was to investigate how the adaptation to a broad range of ecological niches may have selectively shaped the yeast metabolic network to generate specific phenotypes. Using 72 S. cerevisiae strains collected from various sources, we provide, for the first time, a population-scale picture of the fermentative metabolic traits found in the S. cerevisiae species under wine making conditions. Considerable phenotypic variation was found suggesting that this yeast employs diverse metabolic strategies to face environmental constraints. Several groups of strains can be distinguished from the entire population on the basis of specific traits. Strains accustomed to growing in the presence of high sugar concentrations, such as wine yeasts and strains obtained from fruits, were able to achieve fermentation, whereas natural yeasts isolated from “poor-sugar” environments, such as oak trees or plants, were not. Commercial wine yeasts clearly appeared as a subset of vineyard isolates, and were mainly differentiated by their fermentative performances as well as their low acetate production. Overall, the emergence of the origin-dependent properties of the strains provides evidence for a phenotypic evolution driven by environmental constraints and/or human selection within S. cerevisiae. PMID:21949874

Camarasa, Carole; Sanchez, Isabelle; Brial, Pascale; Bigey, Frédéric; Dequin, Sylvie

2011-01-01

316

Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells.  

PubMed

An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack. PMID:25686929

Zhang, Jingtao; Wang, Xiaoxin; Li, Qi; Shang, Jian Ku

2015-04-01

317

Ethanol production from nonsterilized carob pod extract by free and immobilized Saccharomyces cerevisiae cells using fed-batch culture  

Microsoft Academic Search

The production of ethanol from carob pod extract by free and immobilized Saccharomyces cerevisiae cells in batch and fed-batch culture was investigated. Fed-batch culture proved to be a better fermentation system for the production of ethanol than batch culture. In fed-batch culture, both free and immobilized S. cerevisiae cells gave the same maximum concentration of final ethanol at an initial

T. Roukas

1994-01-01

318

The Product of the DNA Damage-Inducible Gene of Saccharomyces cerevisiae, DIN7, Specifically Functions in Mitochondria  

Microsoft Academic Search

We reported previously that the product of the DNA damage-inducible gene of Saccharomyces cerevisiae, DIN7, belongs to a family of proteins that are involved in DNA repair and replication. The family includes S. cerevisiae proteins Rad2p and its human homolog XPGC, Rad27p and its mammalian homolog FEN-1, and Exonuclease I (Exo I). Here, we report that Din7p specifically affects metabolism

Marta U. Fikus; Piotr A. Mieczkowski; Piotr Koprowski; Joanna Rytka; Ewa Sledziewska-Gojska; Zygmunt Ciesla

319

Impact of Acute Metal Stress in Saccharomyces cerevisiae  

PubMed Central

Although considered as essential cofactors for a variety of enzymatic reactions and for important structural and functional roles in cell metabolism, metals at high concentrations are potent toxic pollutants and pose complex biochemical problems for cells. We report results of single dose acute toxicity testing in the model organism S. cerevisiae. The effects of moderate toxic concentrations of 10 different human health relevant metals, Ag+, Al3+, As3+, Cd2+, Co2+, Hg2+, Mn2+, Ni2+, V3+, and Zn2+, following short-term exposure were analyzed by transcription profiling to provide the identification of early-on target genes or pathways. In contrast to common acute toxicity tests where defined endpoints are monitored we focused on the entire genomic response. We provide evidence that the induction of central elements of the oxidative stress response by the majority of investigated metals is the basic detoxification process against short-term metal exposure. General detoxification mechanisms also comprised the induction of genes coding for chaperones and those for chelation of metal ions via siderophores and amino acids. Hierarchical clustering, transcription factor analyses, and gene ontology data further revealed activation of genes involved in metal-specific protein catabolism along with repression of growth-related processes such as protein synthesis. Metal ion group specific differences in the expression responses with shared transcriptional regulators for both, up-regulation and repression were also observed. Additionally, some processes unique for individual metals were evident as well. In view of current concerns regarding environmental pollution our results may support ongoing attempts to develop methods to monitor potentially hazardous areas or liquids and to establish standardized tests using suitable eukaryotic a model organism. PMID:24416162

Lichtenberg-Fraté, Hella; Glaser, Walter; Schüller, Christoph; Klipp, Edda

2014-01-01

320

Effects of proteinase A on cultivation and viability characteristics of industrial Saccharomyces cerevisiae WZ65*  

PubMed Central

Proteinase A (PrA), encoded by PEP4 gene, is a key enzyme in the vacuoles of Saccharomyces cerevisiae. We characterized the effects of PrA on cell growth and glucose metabolism in the industrial S. cerevisiae WZ65. It was observed that the lag phase of cell growth of partial PEP4 gene deletion mutant (36 h) and PrA-negative mutant (48 h) was significantly extended, compared with the wild type strain (24 h) (P<0.05), but PrA had no effect on glucose metabolism either under shaking or steady state cultivations. The logistic model was chosen to evaluate the effect of PrA on S. cerevisiae cell growth, and PrA was found to promote cell growth against insufficient oxygen condition in steady state cultivation, but had no effect in shaking cultivation. The effects of glucose starvation on cell growth of partial PEP4 gene deletion strain and PrA-negative mutant were also evaluated. The results show that PrA partial deficiency increased the adaption of S. cerevisiae to unfavorable nutrient environment, but had no effect on glucose metabolism under the stress of low glucose. During heat shock test, at 60 °C the reduced cell viability rate (RCVR) was 10% for the wild type S. cerevisiae and 90% for both mutant strains (P<0.01), suggesting that PrA was a negative factor for S. cerevisiae cells to survive under heat shock. As temperatures rose from 60 °C to 70 °C, the wild type S. cerevisiae had significantly lower relative glucose consumption rate (RGCR) (61.0% and 80.0%) than the partial mutant (78.0% and 98.5%) and the complete mutant (80.0% and 98.0%) (P<0.05), suggesting that, in coping with heat shock, cells of the PrA mutants increased their glucose consumption to survive. The present study may provide meaningful information for brewing industry; however, the role of PrA in industrial S. cerevisiae physiology is complex and needs to be further investigated. PMID:19817002

Zhang, Hong-bo; Zhang, Hai-feng; Chen, Qi-he; Ruan, Hui; Fu, Ming-liang; He, Guo-qing

2009-01-01

321

High-level production of animal-free recombinant transferrin from saccharomyces cerevisiae  

PubMed Central

Background Animal-free recombinant proteins provide a safe and effective alternative to tissue or serum-derived products for both therapeutic and biomanufacturing applications. While recombinant insulin and albumin already exist to replace their human counterparts in cell culture media, until recently there has been no equivalent for serum transferrin. Results The first microbial system for the high-level secretion of a recombinant transferrin (rTf) has been developed from Saccharomyces cerevisiae strains originally engineered for the commercial production of recombinant human albumin (Novozymes' Recombumin® USP-NF) and albumin fusion proteins (Novozymes' albufuse®). A full-length non-N-linked glycosylated rTf was secreted at levels around ten-fold higher than from commonly used laboratory strains. Modification of the yeast 2 ?m-based expression vector to allow overexpression of the ER chaperone, protein disulphide isomerase, further increased the secretion of rTf approximately twelve-fold in high cell density fermentation. The rTf produced was functionally equivalent to plasma-derived transferrin. Conclusions A Saccharomyces cerevisiae expression system has enabled the cGMP manufacture of an animal-free rTf for industrial cell culture application without the risk of prion and viral contamination, and provides a high-quality platform for the development of transferrin-based therapeutics. PMID:21083917

2010-01-01

322

New aspects of Saccharomyces cerevisiae as a novel carrier for berberine  

PubMed Central

Background Berberine was encapsulated in yeast cells of Saccharomyces cerevisiae as novel carriers to be used in different food and drug industries. The microcapsules were characterized by differential scanning calorimetry (DSC), fourier transform infra red spectroscopy (FT-IR) and fluorescence microscopy. The encapsulation factors such as plasmolysis of yeast cells which affects the % encapsulation yield were studied. Results Fluorescence microscopy showed the yeast cells became fluorescent after encapsulation process. DSC diagram was representing of new peak for microcapsule which was not the same as berberine and the empty yeast cells peaks, separately. FTIR spectrums of microcapsules and yeast cells were almost the same. The plasmolysed and non plasmolysed microcapsules were loaded with berberine up to about 40.2?±?0.2% w/w. Conclusion Analytical methods proved that berberine was encapsulated in the yeast cells. Fluorescence microscopy and FTIR results showed the entrance of berberine inside the yeasts. DSC diagram indicated the appearance of new peak which is due to the synthesis of new product. Although plasmolysis caused changes in yeast cell structure and properties, it did not enhance berberine loading in the cells. The results confirmed that Saccharomyces cerevisiae could be an efficient and safe carrier for active materials. PMID:24359687

2013-01-01

323

Examining the Role of Membrane Lipid Composition in Determining the Ethanol Tolerance of Saccharomyces cerevisiae  

PubMed Central

Yeast (Saccharomyces cerevisiae) has an innate ability to withstand high levels of ethanol that would prove lethal to or severely impair the physiology of other organisms. Significant efforts have been undertaken to elucidate the biochemical and biophysical mechanisms of how ethanol interacts with lipid bilayers and cellular membranes. This research has implicated the yeast cellular membrane as the primary target of the toxic effects of ethanol. Analysis of model membrane systems exposed to ethanol has demonstrated ethanol's perturbing effect on lipid bilayers, and altering the lipid composition of these model bilayers can mitigate the effect of ethanol. In addition, cell membrane composition has been correlated with the ethanol tolerance of yeast cells. However, the physical phenomena behind this correlation are likely to be complex. Previous work based on often divergent experimental conditions and time-consuming low-resolution methodologies that limit large-scale analysis of yeast fermentations has fallen short of revealing shared mechanisms of alcohol tolerance in Saccharomyces cerevisiae. Lipidomics, a modern mass spectrometry-based approach to analyze the complex physiological regulation of lipid composition in yeast and other organisms, has helped to uncover potential mechanisms for alcohol tolerance in yeast. Recent experimental work utilizing lipidomics methodologies has provided a more detailed molecular picture of the relationship between lipid composition and ethanol tolerance. While it has become clear that the yeast cell membrane composition affects its ability to tolerate ethanol, the molecular mechanisms of yeast alcohol tolerance remain to be elucidated. PMID:24610851

Henderson, Clark M.

2014-01-01

324

Cisplatin sensitivity in cAMP-dependent protein kinase mutants of Saccharomyces cerevisiae.  

PubMed

The emergence of cisplatin resistance poses a significant problem to the treatment of a variety of human malignancies. Therefore, understanding the molecular basis of cisplatin resistance could improve the clinical effectiveness of this anticancer agent. Recently, our laboratory has demonstrated that cAMP-dependent protein kinase (PKA) mutants of the Chinese hamster ovary (CHO) and the mouse adrenocortical carcinoma Y1 cells exhibited increased resistance to cisplatin as well as other DNA-damaging drugs. Further studies showed that either the functional inactivation of PKA or the mutation in the regulatory subunit gene may cause increased recognition of cisplatin-damaged DNA and enhanced DNA repair capacity. In this study, we evaluated the role of PKA in modulating cellular sensitivity to cisplatin in a series of PKA mutants of Saccharomyces cerevisiae. Mutants with decreased kinase activity resulting from a srv2 mutation showed no alterations in cisplatin sensitivity. Complementation of TPK1 in a yeast strain containing mutant tpk1 and also tpk2 and tpk3 deletions did not significantly alter its sensitivity to this DNA-damaging agent. Yeast transformants containing increased kinase activity resulting from overexpression of RAS2Val19 or TPK1 and yeast strains having increased kinase activities due to mutations in the BCY1 gene also did not show alterations in their sensitivity to cisplatin. Therefore, results from these studies unambiguously demonstrate that changes in PKA activity have no effect on cisplatin sensitivity in Saccharomyces cerevisiae. PMID:9858882

Cvijic, M E; Yang, W L; Chin, K V

1998-01-01

325

Synthesis of a gene for human serum albumin and its expression in Saccharomyces cerevisiae.  

PubMed Central

A 1761 base pairs long artificial gene coding for human serum albumin (HSA) has been prepared by a newly developed synthetic approach, resulting in the largest synthetic gene so far described. Oligonucleotides corresponding to only one strand of the HSA gene were prepared by chemical synthesis, while the complementary strand was obtained by a combination of enzymatic and cloning steps. 24 synthetic, 69-85 nucleotides long oligonucleotides covering the major part of the HSA gene (41-1761 nucleotides) were used as building blocks. Generally, four groups of 6-6 such oligonucleotides were successively cloned in pUC19 Escherichia coli vector to obtain about quarters of the gene as large fragments. Joining of these four fragments resulted in a cloned DNA coding for the 13-585 amino acid region of HSA, which was further supplemented with a double-stranded linker sequence coding for the amino terminal 12 amino acids. The completed structural gene composed of frequently used codons in the highly expressed yeast genes was then supplied with yeast regulatory sequences and the HSA expression cassette so obtained was inserted into an Escherichia coli-Saccharomyces cerevisiae shuttle vector. This vector was shown to direct the expression in Saccharomyces cerevisiae of correctly processed, mature HSA which was recognized by antiserum to HSA, and possessed the correct N-terminal amino acid sequence. Images PMID:2235491

Kálmán, M; Cserpán, I; Bajszár, G; Dobi, A; Horváth, E; Pázmán, C; Simoncsits, A

1990-01-01

326

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

PubMed Central

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

327

Transcriptome response to alkane biofuels in Saccharomyces cerevisiae: identification of efflux pumps involved in alkane tolerance  

PubMed Central

Background Hydrocarbon alkanes have been recently considered as important next-generation biofuels because microbial production of alkane biofuels was demonstrated. However, the toxicity of alkanes to microbial hosts can possibly be a bottleneck for high productivity of alkane biofuels. To tackle this toxicity issue, it is essential to understand molecular mechanisms of interactions between alkanes and microbial hosts, and to harness these mechanisms to develop microbial host strains with improved tolerance against alkanes. In this study, we aimed to improve the tolerance of Saccharomyces cerevisiae, a model eukaryotic host of industrial significance, to alkane biofuels by exploiting cellular mechanisms underlying alkane response. Results To this end, we first confirmed that nonane (C9), decane (C10), and undecane (C11) were significantly toxic and accumulated in S. cerevisiae. Transcriptome analyses suggested that C9 and C10 induced a range of cellular mechanisms such as efflux pumps, membrane modification, radical detoxification, and energy supply. Since efflux pumps could possibly aid in alkane secretion, thereby reducing the cytotoxicity, we formed the hypothesis that those induced efflux pumps could contribute to alkane export and tolerance. In support of this hypothesis, we demonstrated the roles of the efflux pumps Snq2p and Pdr5p in reducing intracellular levels of C10 and C11, as well as enhancing tolerance levels against C10 and C11. This result provided the evidence that Snq2p and Pdr5p were associated with alkane export and tolerance in S. cerevisiae. Conclusions Here, we investigated the cellular mechanisms of S. cerevisiae response to alkane biofuels at a systems level through transcriptome analyses. Based on these mechanisms, we identified efflux pumps involved in alkane export and tolerance in S. cerevisiae. We believe that the results here provide valuable insights into designing microbial engineering strategies to improve cellular tolerance for highly efficient alkane biofuel production. PMID:23826995

2013-01-01

328

Nuclear Changes occurring during Bud-formation in Saccharomyces cerevisiae as revealed by Ultra-thin Sectioning  

Microsoft Academic Search

THE lack of clarity prevailing among yeast cytologists as to the mode of budding in Saccharomyces cerevisiae tempted us to study this process by means of an improved ultra-thin sectioning technique. This technique has enabled us to observe nuclear behaviour during bud formation and subsequent division. Except for substitution of potassium permanganate for osmium tetroxide as the fixative, the method

T. Hashimoto; S. F. Conti; H. B. Naylor

1958-01-01

329

Rim15p-mediated regulation of sucrose utilization during molasses fermentation using Saccharomyces cerevisiae strain PE-2.  

PubMed

Inherited loss-of-function mutations in the Rim15p-mediated stress-response pathway contribute to the high fermentation rate of sake yeast strains. In the present study, we found that disruption of the RIM15 gene in ethanol-producing Saccharomyces cerevisiae strain PE-2 accelerated molasses fermentation through enhanced sucrose utilization following glucose starvation. PMID:23757382

Inai, Tomomi; Watanabe, Daisuke; Zhou, Yan; Fukada, Rie; Akao, Takeshi; Shima, Jun; Takagi, Hiroshi; Shimoi, Hitoshi

2013-11-01

330

Crystal Structure of the Saccharomyces cerevisiae Ubiquitin-conjugating Enzyme Rad6 at 2.6 Resolution*  

E-print Network

Crystal Structure of the Saccharomyces cerevisiae Ubiquitin-conjugating Enzyme Rad6 at 2.6 Ã? with the DNA binding protein Rad18. We report here the crystal structure of Rad6 refined at 2.6 Ã? reso- lution of previ- ously reported structures. The active site cysteine lies in a cleft formed by a coil region

Hill, Chris

331

3-Isopropylmalate Is the Major Endogenous Substrate of the Saccharomyces cereVisiae trans-Aconitate Methyltransferase  

E-print Network

3-Isopropylmalate Is the Major Endogenous Substrate of the Saccharomyces cereVisiae trans-Aconitate Biology Institute, and the Pasarow Mass Spectrometry Laboratory, Department of Psychiatry and Biobeha the methyl esterification of trans-aconitate, a thermodynamically favored isomer of cis-aconitate

Clarke, Steven

332

Engineered Saccharomyces cerevisiae strain for improved xylose utilization with a three-plasmid SUMO yeast expression system  

Technology Transfer Automated Retrieval System (TEKTRAN)

A three-plasmid yeast expression system utilizing the portable small ubiquitin-like modifier (SUMO) vector set combined with the efficient endogenous yeast protease Ulp1 was developed for production of large amounts of soluble functional protein in Saccharomyces cerevisiae. Each vector has a differ...

333

A positive but complex association between meiotic double-strand break hotspots and open chromatin in Saccharomyces cerevisiae  

Microsoft Academic Search

During meiosis, chromatin undergoes extensive changes to facilitate recombination, homolog pairing, and chromosome segregation. To investigate the relationship between chromatin organization and meiotic processes, we used formaldehyde- assisted isolation of regulatory elements (FAIRE) to map open chromatin during the transition from mitosis to meiosis in the budding yeast Saccharomyces cerevisiae. We found that meiosis-induced opening of chromatin is associated with

Luke E. Berchowitz; Sean E. Hanlon; Jason D. Lieb; Gregory P. Copenhaver

2009-01-01

334

Parameters affecting lithium acetate-mediated transformation of Saccharomyces cerevisiae and development of a rapid and simplified procedure  

Microsoft Academic Search

We have compared a number of procedures for the transformation of whole cells of the yeast Saccharomyces cerevisiae and assessed the effects of dimethylsulphoxide (DMSO) or ethanol, both of which have been reported to enhance transformation efficiency. We find that simplified methods benefit from the addition of one of these compounds, and although differences are observed between strains as to

Rajeev Soni; Jeremy P. Carmichael; James A. H. Murray

1993-01-01

335

Saccharomyces cerevisiae SSD1 orthologues are essential for host infection by the ascomycete plant pathogens Colletotrichum lagenarium and Magnaporthe grisea  

Microsoft Academic Search

Summary Fungal plant pathogens have evolved diverse strate- gies to overcome the multilayered plant defence responses that confront them upon host invasion. Here we show that pathogenicity of the cucumber anthracnose fungus, Colletotrichum lagenarium, and the rice blast fungus, Magnaporthe grisea, requires a gene orthologous to Saccharomyces cerevisiae SSD1, a regulator of cell wall assembly. Screening for C. lagenarium insertional

Shigeyuki Tanaka; Kaori Yamada; Kayo Yabumoto; Satoshi Fujii; Aurélie Huser; Gento Tsuji; Hironori Koga; Koji Dohi; Masashi Mori; Tomonori Shiraishi; Richard O'Connell; Yasuyuki Kubo

2007-01-01

336

ISOLATION OF THE CANDIDA TROPICALIS GENE FOR P450 LANOSTEROL DEMETHYLASE AND ITS EXPRESSION IN SACCHAROMYCES CEREVISIAE  

EPA Science Inventory

We have isolated the gene for cytochrome P450 lanosterol 14a-demethylase (14DM) from the yeast Candida tropicalis. his was accomplished by screening genomic libraries of strain ATCC750 in E. coli using a DNA fragment containing the yeast Saccharomyces cerevisiae 14DM gene. dentit...

337

Stereochemistry of Furfural Reduction by a Saccharomyces cerevisiae Aldehyde Reductase That Contributes to In Situ Furfural Detoxification  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ari1p from Saccharomyces cerevisiae, recently identified as an intermediate subclass short-chain dehydrogenase/reductase, contributes in situ to the detoxification of furfural. Furfural inhibits efficient ethanol production by the yeast, particularly when the carbon source is acid-treated lignocell...

338

GENOME-WIDE ASSOCIATION ANALYSIS OF CLINICAL VERSUS NON-CLINICAL ORIGIN PROVIDES INSIGHTS INTO SACCHAROMYCES CEREVISIAE PATHOGENESIS  

PubMed Central

Because domesticated Saccharomyces cerevisiae strains have been used to produce fermented food and beverages for centuries without apparent health implications, S. cerevisiae has always been considered a Generally Recognized As Safe (GRAS) microorganism. However, the number of reported mucosal and systemic S. cerevisiae infections in the human population has increased and fatal infections have occured even in relatively healthy individuals. In order to gain insight into the pathogenesis of S. cerevisiae and improve our understanding of the emergence of fungal pathogens, we performed a population-based genome-wide environmental association analysis of clinical versus non-clinical origin in S. cerevisiae. Using tiling array-based, high density genotypes of 44 clinical and 44 non-clinical S. cerevisiae strains from diverse geographical origins and source substrates, we identified several genetic loci associated with clinical background in S. cerevisiae. Associated polymorphisms within the coding sequences of VRP1, KIC1, SBE22 and PDR5, and the 5? upstream region of YGR146C indicate the importance of pseudohyphal formation, robust cell wall maintenance and cellular detoxification for S. cerevisiae pathogenesis, and constitute good candidates for follow-up verification of virulence and virulence-related factors underlying the pathogenicity of S. cerevisiae. PMID:21880084

Muller, Ludo A. H.; Lucas, Joseph E.; Georgianna, D. Ryan; McCusker, John H.

2011-01-01

339

Statistics-based model for prediction of chemical biosynthesis yield from Saccharomyces cerevisiae  

PubMed Central

Background The robustness of Saccharomyces cerevisiae in facilitating industrial-scale production of ethanol extends its utilization as a platform to synthesize other metabolites. Metabolic engineering strategies, typically via pathway overexpression and deletion, continue to play a key role for optimizing the conversion efficiency of substrates into the desired products. However, chemical production titer or yield remains difficult to predict based on reaction stoichiometry and mass balance. We sampled a large space of data of chemical production from S. cerevisiae, and developed a statistics-based model to calculate production yield using input variables that represent the number of enzymatic steps in the key biosynthetic pathway of interest, metabolic modifications, cultivation modes, nutrition and oxygen availability. Results Based on the production data of about 40 chemicals produced from S. cerevisiae, metabolic engineering methods, nutrient supplementation, and fermentation conditions described therein, we generated mathematical models with numerical and categorical variables to predict production yield. Statistically, the models showed that: 1. Chemical production from central metabolic precursors decreased exponentially with increasing number of enzymatic steps for biosynthesis (>30% loss of yield per enzymatic step, P-value = 0); 2. Categorical variables of gene overexpression and knockout improved product yield by 2~4 folds (P-value < 0.1); 3. Addition of notable amount of intermediate precursors or nutrients improved product yield by over five folds (P-value < 0.05); 4. Performing the cultivation in a well-controlled bioreactor enhanced the yield of product by three folds (P-value < 0.05); 5. Contribution of oxygen to product yield was not statistically significant. Yield calculations for various chemicals using the linear model were in fairly good agreement with the experimental values. The model generally underestimated the ethanol production as compared to other chemicals, which supported the notion that the metabolism of Saccharomyces cerevisiae has historically evolved for robust alcohol fermentation. Conclusions We generated simple mathematical models for first-order approximation of chemical production yield from S. cerevisiae. These linear models provide empirical insights to the effects of strain engineering and cultivation conditions toward biosynthetic efficiency. These models may not only provide guidelines for metabolic engineers to synthesize desired products, but also be useful to compare the biosynthesis performance among different research papers. PMID:21689458

2011-01-01

340

Arabinose and xylose fermentation by recombinant Saccharomyces cerevisiae expressing a fungal pentose utilization pathway  

PubMed Central

Background Sustainable and economically viable manufacturing of bioethanol from lignocellulose raw material is dependent on the availability of a robust ethanol producing microorganism, able to ferment all sugars present in the feedstock, including the pentose sugars L-arabinose and D-xylose. Saccharomyces cerevisiae is a robust ethanol producer, but needs to be engineered to achieve pentose sugar fermentation. Results A new recombinant S. cerevisiae strain expressing an improved fungal pathway for the utilization of L-arabinose and D-xylose was constructed and characterized. The new strain grew aerobically on L-arabinose and D-xylose as sole carbon sources. The activities of the enzymes constituting the pentose utilization pathway(s) and product formation during anaerobic mixed sugar fermentation were characterized. Conclusion Pentose fermenting recombinant S. cerevisiae strains were obtained by the expression of a pentose utilization pathway of entirely fungal origin. During anaerobic fermentation the strain produced biomass and ethanol. L-arabitol yield was 0.48 g per gram of consumed pentose sugar, which is considerably less than previously reported for D-xylose reductase expressing strains co-fermenting L-arabinose and D-xylose, and the xylitol yield was 0.07 g per gram of consumed pentose sugar. PMID:19630951

Bettiga, Maurizio; Bengtsson, Oskar; Hahn-Hägerdal, Bärbel; Gorwa-Grauslund, Marie F

2009-01-01

341

Catalase Overexpression Reduces Lactic Acid-Induced Oxidative Stress in Saccharomyces cerevisiae?  

PubMed Central

Industrial production of lactic acid with the current pyruvate decarboxylase-negative Saccharomyces cerevisiae strains requires aeration to allow for respiratory generation of ATP to facilitate growth and, even under nongrowing conditions, cellular maintenance. In the current study, we observed an inhibition of aerobic growth in the presence of lactic acid. Unexpectedly, the cyb2? reference strain, used to avoid aerobic consumption of lactic acid, had a specific growth rate of 0.25 h?1 in anaerobic batch cultures containing lactic acid but only 0.16 h?1 in identical aerobic cultures. Measurements of aerobic cultures of S. cerevisiae showed that the addition of lactic acid to the growth medium resulted in elevated levels of reactive oxygen species (ROS). To reduce the accumulation of lactic acid-induced ROS, cytosolic catalase (CTT1) was overexpressed by replacing the native promoter with the strong constitutive TPI1 promoter. Increased activity of catalase was confirmed and later correlated with decreased levels of ROS and increased specific growth rates in the presence of high lactic acid concentrations. The increased fitness of this genetically modified strain demonstrates the successful attenuation of additional stress that is derived from aerobic metabolism and may provide the basis for enhanced (micro)aerobic production of organic acids in S. cerevisiae. PMID:19251894

Abbott, Derek A.; Suir, Erwin; Duong, Giang-Huong; de Hulster, Erik; Pronk, Jack T.; van Maris, Antonius J. A.

2009-01-01

342

CAL1, a gene required for activity of chitin synthase 3 in Saccharomyces cerevisiae  

PubMed Central

The CAL1 gene was cloned by complementation of the defect in Calcofluor- resistant calR1 mutants of Saccharomyces cerevisiae. Transformation of the mutants with a plasmid carrying the appropriate insert restored Calcofluor sensitivity, wild-type chitin levels and normal spore maturation. Southern blots using the DNA fragment as a probe showed hybridization to a single locus. Allelic tests indicated that the cloned gene corresponded to the calR1 locus. The DNA insert contains a single open-reading frame encoding a protein of 1,099 amino acids with a molecular mass of 124 kD. The predicted amino acid sequence shows several regions of homology with those of chitin synthases 1 and 2 from S. cerevisiae and chitin synthase 1 from Candida albicans. calR1 mutants have been found to be defective in chitin synthase 3, a trypsin- independent synthase. Transformation of the mutants with a plasmid carrying CAL1 restored chitin synthase 3 activity; however, overexpression of the enzyme was not achieved even with a high copy number plasmid. Since Calcofluor-resistance mutations different from calR1 also result in reduced levels of chitin synthase 3, it is postulated that the products of some of these CAL genes may be limiting for expression of the enzymatic activity. Disruption of the CAL1 gene was not lethal, indicating that chitin synthase 3 is not an essential enzyme for S. cerevisiae. PMID:2050737

1991-01-01

343

CTP synthetase and its role in phospholipid synthesis in the yeast Saccharomyces cerevisiae  

PubMed Central

CTP synthetase is a cytosolic-associated glutamine amidotransferase enzyme that catalyzes the ATP-dependent transfer of the amide nitrogen from glutamine to the C-4 position of UTP to form CTP. In the yeast Saccharomyces cerevisiae, the reaction product CTP is an essential precursor of all membrane phospholipids that are synthesized via the Kennedy (CDP-choline and CDP-ethanolamine branches) and CDP-diacylglycerol pathways. The URA7 and URA8 genes encode CTP synthetase in S. cerevisiae, and the URA7 gene is responsible for the majority of CTP synthesized in vivo. The CTP synthetase enzymes are allosterically regulated by CTP product inhibition. Mutations that alleviate this regulation result in an elevated cellular level of CTP and an increase in phospholipid synthesis via the Kennedy pathway. The URA7-encoded enzyme is phosphorylated by protein kinases A and C, and these phosphorylations stimulate CTP synthetase activity and increase cellular CTP levels and the utilization of the Kennedy pathway. The CTPS1 and CTPS2 genes that encode human CTP synthetase enzymes are functionally expressed in S. cerevisiae, and rescue the lethal phenotype of the ura7? ura8? double mutant that lacks CTP synthetase activity. The expression in yeast has revealed that the human CTPS1-encoded enzyme is also phosphorylated and regulated by protein kinases A and C. PMID:18439916

Chang, Yu-Fang; Carman, George M.

2008-01-01

344

Effects of microcystin-LR on Saccharomyces cerevisiae growth, oxidative stress and apoptosis.  

PubMed

Microcystins (MC) are cyanotoxins occurring globally, known for causing acute hepatotoxicity in humans/animals, tumor promotion in animals and potential carcinogenicity. The mechanism of MC toxicity is considered a multi-pathway process involving the inhibition of protein phosphatases PP1/PP2A and the production of reactive oxygen species (ROS). However, their mechanism of action is not fully characterized, thus hampering the complete hazard identification. In this study, we evaluated the effect of several microcystin-LR concentrations on the growth, ROS levels, antioxidant system response and apoptosis induction on Saccharomyces cerevisiae. Our results showed that the growth of S. cerevisiae was not inhibited when compared to control cells. However, the staining of cells with DHR123 and DHE revealed an intracellular increase of the ROS levels. This ROS increase resulted in an augment of catalase activity and inhibition of SOD. All these facts suggest that hydrogen peroxide was the main ROS induced by MCLR. Signs of apoptosis were also detected in the cells exposed to toxin. Our results show that S. cerevisiae VL3 displays MCLR toxicity effects known to occur in higher eukaryotes and confirmed that it can be a simple and good model to help further in the elucidation of MCLR molecular mechanisms of toxicity. PMID:25157802

Valério, Elisabete; Vilares, Arminda; Campos, Alexandre; Pereira, Paulo; Vasconcelos, Vitor

2014-11-01

345

Synthetic organotelluride compounds induce the reversal of Pdr5p mediated fluconazole resistance in Saccharomyces cerevisiae  

PubMed Central

Background Resistance to fluconazole, a commonly used azole antifungal, is a challenge for the treatment of fungal infections. Resistance can be mediated by overexpression of ABC transporters, which promote drug efflux that requires ATP hydrolysis. The Pdr5p ABC transporter of Saccharomyces cerevisiae is a well-known model used to study this mechanism of antifungal resistance. The present study investigated the effects of 13 synthetic compounds on Pdr5p. Results Among the tested compounds, four contained a tellurium-butane group and shared structural similarities that were absent in the other tested compounds: a lateral hydrocarbon chain and an amide group. These four compounds were capable of inhibiting Pdr5p ATPase activity by more than 90%, they demonstrated IC50 values less than 2 ?M and had an uncompetitive pattern of Pdr5p ATPase activity inhibition. These organotellurides did not demonstrate cytotoxicity against human erythrocytes or S. cerevisiae mutant strains (a strain that overexpress Pdr5p and a null mutant strain) even in concentrations above 100 ?M. When tested at 100 ?M, they could reverse the fluconazole resistance expressed by both the S. cerevisiae mutant strain that overexpress Pdr5p and a clinical isolate of Candida albicans. Conclusions We have identified four organotellurides that are promising candidates for the reversal of drug resistance mediated by drug efflux pumps. These molecules will act as scaffolds for the development of more efficient and effective efflux pump inhibitors that can be used in combination therapy with available antifungals. PMID:25062749

2014-01-01

346

Molecular Characterization of Propolis-Induced Cell Death in Saccharomyces cerevisiae  

PubMed Central

Propolis, a natural product of plant resins, is used by the bees to seal holes in their honeycombs and protect the hive entrance. However, propolis has also been used in folk medicine for centuries. Here, we apply the power of Saccharomyces cerevisiae as a model organism for studies of genetics, cell biology, and genomics to determine how propolis affects fungi at the cellular level. Propolis is able to induce an apoptosis cell death response. However, increased exposure to propolis provides a corresponding increase in the necrosis response. We showed that cytochrome c but not endonuclease G (Nuc1p) is involved in propolis-mediated cell death in S. cerevisiae. We also observed that the metacaspase YCA1 gene is important for propolis-mediated cell death. To elucidate the gene functions that may be required for propolis sensitivity in eukaryotes, the full collection of about 4,800 haploid S. cerevisiae deletion strains was screened for propolis sensitivity. We were able to identify 138 deletion strains that have different degrees of propolis sensitivity compared to the corresponding wild-type strains. Systems biology revealed enrichment for genes involved in the mitochondrial electron transport chain, vacuolar acidification, negative regulation of transcription from RNA polymerase II promoter, regulation of macroautophagy associated with protein targeting to vacuoles, and cellular response to starvation. Validation studies indicated that propolis sensitivity is dependent on the mitochondrial function and that vacuolar acidification and autophagy are important for yeast cell death caused by propolis. PMID:21193549

de Castro, Patrícia Alves; Savoldi, Marcela; Bonatto, Diego; Barros, Mário Henrique; Goldman, Maria Helena S.; Berretta, Andresa A.; Goldman, Gustavo Henrique

2011-01-01

347

Analysis of nitrated proteins in Saccharomyces cerevisiae involved in mating signal transduction.  

PubMed

Protein tyrosine nitration (PTN) is a post-translational modification that regulates signal transduction and inflammatory responses, and is related to neurodegenerative and cardiovascular diseases. The cellular function of PTN remains unclear because the low stoichiometry of PTN limits the identification and quantification of nitrated peptides. Effective enrichment is an important aspect of PTN analysis. In this study, we analyzed the in vivo nitroproteome elicited by mating signal transduction in Saccharomyces cerevisiae using a novel chemical enrichment method followed by liquid chromatography tandem mass (LC-MS/MS). Nitroproteome profiling successfully identified changes in the nitration states of 14 proteins during mating signal transduction in S. cerevisiae, making this the first reported in vivo nitroproteome in yeast. We investigated the biological functions of these nitroproteins and their relationships to mating signal transduction in S. cerevisiae using a protein-protein interaction network. Our results suggest that PTN and denitration may be involved in non-reactive nitrogen species-mediated signal transduction and can provide clues for understanding the functional roles of PTN in vivo. This article is protected by copyright. All rights reserved. PMID:25204828

Kang, Jeong Won; Lee, Na Young; Cho, Kyung-Cho; Lee, Min Young; Choi, Do-Young; Park, Sang-Hyun; Kim, Kwang Pyo

2014-09-10

348

Saccharomyces cerevisiae KNU5377 Stress Response during High-Temperature Ethanol Fermentation  

PubMed Central

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 dehydrogenase, isocitrate dehydrogenase, and alcohol dehydrogenase), antioxidant enzymes (thioredoxin 3, thioredoxin reductase, and porin), and molecular chaperones and its cofactors (Hsp104, Hsp82, Hsp60, Hsp42, Hsp30, Hsp26, Cpr1, Sti1, and Zpr1) are upregulated during fermentation, in comparison to S. cerevisiae S288C (S288C). Expression of glyceraldehyde-3-phosphate dehydrogenase increased significantly in KNU5377 cells. In addition, cellular hydroperoxide and protein oxidation, particularly lipid peroxidation of triosephosphate isomerase, was lower in KNU5377 than in S288C. Thus, KNU5377 activates various cell rescue proteins through transcription activators, improving tolerance and increasing alcohol yield by rapidly responding to fermentation stress through redox homeostasis and proteostasis. PMID:23512334

Kim, Il-Sup; Kim, Young-Saeng; Kim, Hyun; Jin, Ingnyol; Yoon, Ho-Sung

2013-01-01

349

Construction of a flocculent Saccharomyces cerevisiae strain secreting high levels of Aspergillus niger beta-galactosidase.  

PubMed

A flocculent Saccharomyces cerevisiae strain secreting Aspergillus niger beta-galactosidase activity was constructed by transforming S. cerevisiae NCYC869-A3 strain with plasmid pVK1.1 harboring the A. niger beta-galactosidase gene, lacA, under the control of the ADH1 promoter and terminator. Compared to other recombinant S. cerevisiae strains, this recombinant yeast has higher levels of extracellular beta-galactosidase activity. In shake-flask cultures, the beta-galactosidase activity detected in the supernatant was 20 times higher than that obtained with previously constructed strains (Domingues et al. 2000a). In bioreactor culture, with cheese-whey permeate as substrate, a yield of 878.0 nkat/gsubstrate was obtained. The recombinant strain is an attractive alternative to other fungal beta-galactosidase production systems as the enzyme is produced in a rather pure form. Moreover, the use of flocculating yeast cells allows for enzyme production with high productivity in continuous fermentation systems with facilitated downstream processing. PMID:11956748

Domingues, L; Teixeira, J A; Penttilä, M; Lima, N

2002-04-01

350

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

PubMed

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

351

Analysis of functional domain organization in DNA topoisomerase II from humans and Saccharomyces cerevisiae.  

PubMed Central

The functional domain structure of human DNA topoisomerase IIalpha and Saccharomyces cerevisiae DNA topoisomerase II was studied by investigating the abilities of insertion and deletion mutant enzymes to support mitotic growth and catalyze transitions in DNA topology in vitro. Alignment of the human topoisomerase IIalpha and S. cerevisiae topoisomerase II sequences defined 13 conserved regions separated by less conserved or differently spaced sequences. The spatial tolerance of the spacer regions was addressed by insertion of linkers. The importance of the conserved regions was assessed through deletion of individual domains. We found that the exact spacing between most of the conserved domains is noncritical, as insertions in the spacer regions were tolerated with no influence on complementation ability. All conserved domains, however, are essential for sustained mitotic growth of S. cerevisiae and for enzymatic activity in vitro. A series of topoisomerase II carboxy-terminal truncations were investigated with respect to the ability to support viability, cellular localization, and enzymatic properties. The analysis showed that the divergent carboxy-terminal region of human topoisomerase IIalpha is dispensable for catalytic activity but contains elements that specifically locate the protein to the nucleus. PMID:8668204

Jensen, S; Andersen, A H; Kjeldsen, E; Biersack, H; Olsen, E H; Andersen, T B; Westergaard, O; Jakobsen, B K

1996-01-01

352

Opuntia ficus-indica cladodes as feedstock for ethanol production by Kluyveromyces marxianus and Saccharomyces cerevisiae.  

PubMed

The feasibility of ethanol production using an enzymatic hydrolysate of pretreated cladodes of Opuntia ficus-indica (prickly pear cactus) as carbohydrate feedstock was investigated, including a comprehensive chemical analysis of the cladode biomass and the effects of limited aeration on the fermentation profiles and sugar utilization. The low xylose and negligible mannose content of the cladode biomass used in this study suggested that the hemicellulose structure of the O. ficus-indica cladode was atypical of hardwood or softwood hemicelluloses. Separate hydrolysis and fermentation and simultaneous saccharification and fermentation procedures using Kluyveromyces marxianus and Saccharomyces cerevisiae at 40 and 35 °C, respectively, gave similar ethanol yields under non-aerated conditions. In oxygen-limited cultures K. marxianus exhibited almost double the ethanol productivity compared to non-aerated cultures, although after sugar depletion utilization of the produced ethanol was evident. Ethanol concentrations of up to 19.5 and 20.6 g l(-1) were obtained with K. marxianus and S. cerevisiae, respectively, representing 66 and 70 % of the theoretical yield on total sugars in the hydrolysate. Because of the low xylan content of the cladode biomass, a yeast capable of xylose fermentation might not be a prerequisite for ethanol production. K. marxianus, therefore, has potential as an alternative to S. cerevisiae for bioethanol production. However, the relatively low concentration of fermentable sugars in the O. ficus-indica cladode hydrolysate presents a technical constraint for commercial exploitation. PMID:25248867

Kuloyo, Olukayode O; du Preez, James C; García-Aparicio, Maria del Prado; Kilian, Stephanus G; Steyn, Laurinda; Görgens, Johann

2014-12-01

353

Application of Saccharomyces cerevisiae and Pichia stipitis karyoductants to the production of ethanol from xylose.  

PubMed

Karyoductants of Saccharomyces cerevisiae V30 and Pichia stipitis CCY 39501 with the ability to ferment D-xylose to ethanol were isolated. The ability of these isolates to assimilate different sugars, ethanol tolerance and ethanol production from D-xylose was investigated. Karyoductants didn't grow on starch, lactose and cellobiose, like S. cerevisiae, but showed good growth on xylose and L-arabinose, like P. stipitis. All isolates fermented xylose to ethanol slower than P. stipitis and with lower yields, 0.09 - 0.16 g/g. They secreted also about 3.4 - 7.1 g/dm3 of xylitol to the culture medium (P. stipitis only 0.06 g/dm3). The karyoductants showed an average tolerance to ethanol when compared with the parent strains and fermented glucose in the presence of 6% alcohol whereas parent strain S. cerevisiae and P. stipitis showed exogenic ethanol tolerance of 9% and 3%, respectively. PMID:11930997

Kordowska-Wiater, M; Targo?ski, Z

2001-01-01

354

Expression of an Aspergillus niger phytase gene (phyA) in Saccharomyces cerevisiae.  

PubMed

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals and reduces phosphorus pollution of animal waste. Our objectives were to express an Aspergillus niger phytase gene (phyA) in Saccharomyces cerevisiae and to determine the effects of glycosylation on the phytase's activity and thermostability. A 1.4-kb DNA fragment containing the coding region of the phyA gene was inserted into the expression vector pYES2 and was expressed in S. cerevisiae as an active, extracellular phytase. The yield of total extracellular phytase activity was affected by the signal peptide and the medium composition. The expressed phytase had two pH optima (2 to 2.5 and 5 to 5.5) and a temperature optimum between 55 and 60 degrees C, and it cross-reacted with a rabbit polyclonal antibody against the wild-type enzyme. Due to the heavy glycosylation, the expressed phytase had a molecular size of approximately 120 kDa and appeared to be more thermostable than the commercial enzyme. Deglycosylation of the phytase resulted in losses of 9% of its activity and 40% of its thermostability. The recombinant phytase was effective in hydrolyzing phytate phosphorus from corn or soybean meal in vitro. In conclusion, the phyA gene was expressed as an active, extracellular phytase in S. cerevisiae, and its thermostability was affected by glycosylation. PMID:10223979

Han, Y; Wilson, D B; Lei, X G

1999-05-01

355

Expression of an Aspergillus niger Phytase Gene (phyA) in Saccharomyces cerevisiae  

PubMed Central

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals and reduces phosphorus pollution of animal waste. Our objectives were to express an Aspergillus niger phytase gene (phyA) in Saccharomyces cerevisiae and to determine the effects of glycosylation on the phytase’s activity and thermostability. A 1.4-kb DNA fragment containing the coding region of the phyA gene was inserted into the expression vector pYES2 and was expressed in S. cerevisiae as an active, extracellular phytase. The yield of total extracellular phytase activity was affected by the signal peptide and the medium composition. The expressed phytase had two pH optima (2 to 2.5 and 5 to 5.5) and a temperature optimum between 55 and 60°C, and it cross-reacted with a rabbit polyclonal antibody against the wild-type enzyme. Due to the heavy glycosylation, the expressed phytase had a molecular size of approximately 120 kDa and appeared to be more thermostable than the commercial enzyme. Deglycosylation of the phytase resulted in losses of 9% of its activity and 40% of its thermostability. The recombinant phytase was effective in hydrolyzing phytate phosphorus from corn or soybean meal in vitro. In conclusion, the phyA gene was expressed as an active, extracellular phytase in S. cerevisiae, and its thermostability was affected by glycosylation. PMID:10223979

Han, Yanming; Wilson, David B.; Lei, Xin gen

1999-01-01

356

Blocking endocytotic mechanisms to improve heterologous protein titers in Saccharomyces cerevisiae.  

PubMed

Saccharomyces cerevisiae is a useful platform for protein production of biopharmaceuticals and industrial enzymes. To date, substantial effort has focused on alleviating several bottlenecks in expression and the secretory pathway. Recently, it has been shown that highly active endocytosis could decrease the overall protein titer in the supernatant. In this study, we block endocytosis and trafficking to the vacuole using a modified TEV Protease-Mediated Induction of Protein Instability (mTIPI) system to disrupt the endocytotic and vacuolar complexes. We report that conditional knock-down of endocytosis gene Rvs161 improved the concentration of ?-amylase in supernatant of S. cerevisiae cultures by 63.7% compared to controls. By adaptive evolution, we obtained knock-down mutants in Rvs161 and End3 genes with 2-fold and 3-fold ?-amylase concentrations compared to controls that were not evolved. Our study demonstrates that genetic blocking of endocytotic mechanisms can improve heterologous protein production in S. cerevisiae. This result is likely generalizable to other eukaryotic secretion hosts. Biotechnol. Bioeng. 2015;112: 376-385. © 2014 Wiley Periodicals, Inc. PMID:25154809

Rodríguez-Limas, William A; Tannenbaum, Victoria; Tyo, Keith E J

2015-02-01

357

Baker's yeast (Saccharomyces cerevisiae) antigen in obese and normal weight subjects.  

PubMed

Baker's yeast (Saccharomyces cerevisiae) and its cell wall components have been used as one of the alternatives to antibiotic growth promoters in the feed industry. Antibodies to cell wall mannan of this yeast (ASCA) have been traditionally used in the study of Crohn's disease (CD). We applied ASCA in relation to obesity. This study aims (i) to determine the concentration of ASCA (immunoglobulin A [IgA] and immunoglobulin G [IgG]) in obese compared with normal weight individuals and (ii) to determine if there is a correlation between ASCA concentrations, obesity indices and C-reactive protein. Forty obese individuals (body mass index [BMI]?>?35?kg?m(-2) ) and 18 healthy (BMI?cerevisiae was measured by enzyme-linked immunosorbent assay. More than one-third of the obese individual (35%) showed elevated titres of ASCA compared with the control group (5%). This antibody was positively associated with weight (P?=?0.01), BMI (P?=?0.02) and waist circumference (P?=?0.02), but not with C-reactive protein. It seems that ASCA are not only specific for CD but are also associated with obesity. S.?cerevisiae or a related antigen may play a role in the matrix of this complex condition. PMID:25611585

Salamati, S; Martins, C; Kulseng, B

2015-02-01

358

L-Histidine Inhibits Biofilm Formation and FLO11-Associated Phenotypes in Saccharomyces cerevisiae Flor Yeasts  

PubMed Central

Flor yeasts of Saccharomyces cerevisiae have an innate diversity of FLO11 which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling FLO11 alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce FLO11p. The flor strains generally metabolized amino acids and dipeptides as the sole nitrogen source, although with some exceptions regarding L-histidine and histidine containing dipeptides. L-histidine completely inhibited growth and its effect on viability was inversely related to FLO11 expression. Accordingly, L-histidine did not affect the viability of the ?flo11 and S288c strains. Also, L-histidine dramatically decreased air–liquid biofilm formation and adhesion to polystyrene of the flor yeasts with no effect on the transcription level of the FLO11 gene. Moreover, L-histidine modified the chitin and glycans content on the cell-wall of flor yeasts. These findings reveal a novel biological activity of L-histidine in controlling the multicellular behavior of yeasts. PMID:25369456

Bou Zeidan, Marc; Zara, Giacomo; Viti, Carlo; Decorosi, Francesca; Mannazzu, Ilaria; Budroni, Marilena; Giovannetti, Luciana; Zara, Severino

2014-01-01

359

Identification of a gene, FMP21, whose expression levels are involved in thermotolerance in Saccharomyces cerevisiae  

PubMed Central

Elucidation of the mechanism of high temperature tolerance in yeasts is important for the molecular breeding of high temperature-tolerant yeasts that can be used in bioethanol production. We identified genes whose expression is correlated with the degree of thermotolerance in Saccharomyces cerevisiae by DNA microarray analysis. Gene expression profiles of three S. cerevisiae strains showing different levels of thermotolerance were compared, and we chose three of them as candidate genes. Among these genes, FMP21 was investigated as a thermotolerance-related gene in S. cerevisiae by comparing the growth at high temperature with the gene expression in eight strains. The expression ratio of FMP21 at 37°C was correlated with the doubling time ratio at a coefficient of determination of 0.787. The potential involvement of the Fmp21 in the thermotolerance of yeasts was evaluated. The FMP21 deletion variant showed a decreased respiratory growth rate and increased thermosensitivity. Furthermore, the overexpression of FMP21 improved thermotolerance in yeasts. In conclusion, the function of Fmp21 is important for thermotolerance in yeasts. PMID:25177541

2014-01-01

360

Comparative Proteomics Analysis of Engineered Saccharomyces cerevisiae with Enhanced Biofuel Precursor Production  

PubMed Central

The yeast Saccharomyces cerevisiae was metabolically modified for enhanced biofuel precursor production by knocking out genes encoding mitochondrial isocitrate dehydrogenase and over-expression of a heterologous ATP-citrate lyase. A comparative iTRAQ-coupled 2D LC-MS/MS analysis was performed to obtain a global overview of ubiquitous protein expression changes in S. cerevisiae engineered strains. More than 300 proteins were identified. Among these proteins, 37 were found differentially expressed in engineered strains and they were classified into specific categories based on their enzyme functions. Most of the proteins involved in glycolytic and pyruvate branch-point pathways were found to be up-regulated and the proteins involved in respiration and glyoxylate pathway were however found to be down-regulated in engineered strains. Moreover, the metabolic modification of S. cerevisiae cells resulted in a number of up-regulated proteins involved in stress response and differentially expressed proteins involved in amino acid metabolism and protein biosynthesis pathways. These LC-MS/MS based proteomics analysis results not only offered extensive information in identifying potential protein-protein interactions, signal pathways and ubiquitous cellular changes elicited by the engineered pathways, but also provided a meaningful biological information platform serving further modification of yeast cells for enhanced biofuel production. PMID:24376832

Tang, Xiaoling; Feng, Huixing; Zhang, Jianhua; Chen, Wei Ning

2013-01-01

361

Approaching a complete repository of sequence-verified protein-encoding clones for Saccharomyces cerevisiae  

PubMed Central

The availability of an annotated genome sequence for the yeast Saccharomyces cerevisiae has made possible the proteome-scale study of protein function and protein–protein interactions. These studies rely on availability of cloned open reading frame (ORF) collections that can be used for cell-free or cell-based protein expression. Several yeast ORF collections are available, but their use and data interpretation can be hindered by reliance on now out-of-date annotations, the inflexible presence of N- or C-terminal tags, and/or the unknown presence of mutations introduced during the cloning process. High-throughput biochemical and genetic analyses would benefit from a “gold standard” (fully sequence-verified, high-quality) ORF collection, which allows for high confidence in and reproducibility of experimental results. Here, we describe Yeast FLEXGene, a S. cerevisiae protein-coding clone collection that covers over 5000 predicted protein-coding sequences. The clone set covers 87% of the current S. cerevisiae genome annotation and includes full sequencing of each ORF insert. Availability of this collection makes possible a wide variety of studies from purified proteins to mutation suppression analysis, which should contribute to a global understanding of yeast protein function. PMID:17322287

Hu, Yanhui; Rolfs, Andreas; Bhullar, Bhupinder; Murthy, Tellamraju V. S.; Zhu, Cong; Berger, Michael F.; Camargo, Anamaria A.; Kelley, Fontina; McCarron, Seamus; Jepson, Daniel; Richardson, Aaron; Raphael, Jacob; Moreira, Donna; Taycher, Elena; Zuo, Dongmei; Mohr, Stephanie; Kane, Michael F.; Williamson, Janice; Simpson, Andrew; Bulyk, Martha L.; Harlow, Edward; Marsischky, Gerald; Kolodner, Richard D.; LaBaer, Joshua

2007-01-01

362

Saccharomyces cerevisiae KNU5377 stress response during high-temperature ethanol fermentation.  

PubMed

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 dehydrogenase, isocitrate dehydrogenase, and alcohol dehydrogenase), antioxidant enzymes (thioredoxin 3, thioredoxin reductase, and porin), and molecular chaperones and its cofactors (Hsp104, Hsp82, Hsp60, Hsp42, Hsp30, Hsp26, Cpr1, Sti1, and Zpr1) are upregulated during fermentation, in comparison to S. cerevisiae S288C (S288C). Expression of glyceraldehyde-3-phosphate dehydrogenase increased significantly in KNU5377 cells. In addition, cellular hydroperoxide and protein oxidation, particularly lipid peroxidation of triosephosphate isomerase, was lower in KNU5377 than in S288C. Thus, KNU5377 activates various cell rescue proteins through transcription activators, improving tolerance and increasing alcohol yield by rapidly responding to fermentation stress through redox homeostasis and proteostasis. PMID:23512334

Kim, Il-Sup; Kim, Young-Saeng; Kim, Hyun; Jin, Ingnyol; Yoon, Ho-Sung

2013-03-01

363

Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae.  

PubMed

The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. PMID:22866331

Miller, Kristen P; Gowtham, Yogender Kumar; Henson, J Michael; Harcum, Sarah W

2012-01-01

364

Proteome-wide Analysis of Lysine Acetylation Suggests its Broad Regulatory Scope in Saccharomyces cerevisiae*  

PubMed Central

Post-translational modification of proteins by lysine acetylation plays important regulatory roles in living cells. The budding yeast Saccharomyces cerevisiae is a widely used unicellular eukaryotic model organism in biomedical research. S. cerevisiae contains several evolutionary conserved lysine acetyltransferases and deacetylases. However, only a few dozen acetylation sites in S. cerevisiae are known, presenting a major obstacle for further understanding the regulatory roles of acetylation in this organism. Here we use high resolution mass spectrometry to identify about 4000 lysine acetylation sites in S. cerevisiae. Acetylated proteins are implicated in the regulation of diverse cytoplasmic and nuclear processes including chromatin organization, mitochondrial metabolism, and protein synthesis. Bioinformatic analysis of yeast acetylation sites shows that acetylated lysines are significantly more conserved compared with nonacetylated lysines. A large fraction of the conserved acetylation sites are present on proteins involved in cellular metabolism, protein synthesis, and protein folding. Furthermore, quantification of the Rpd3-regulated acetylation sites identified several previously known, as well as new putative substrates of this deacetylase. Rpd3 deficiency increased acetylation of the SAGA (Spt-Ada-Gcn5-Acetyltransferase) complex subunit Sgf73 on K33. This acetylation site is located within a critical regulatory domain in Sgf73 that interacts with Ubp8 and is involved in the activation of the Ubp8-containing histone H2B deubiquitylase complex. Our data provides the first global survey of acetylation in budding yeast, and suggests a wide-ranging regulatory scope of this modification. The provided dataset may serve as an important resource for the functional analysis of lysine acetylation in eukaryotes. PMID:22865919

Henriksen, Peter; Wagner, Sebastian A.; Weinert, Brian T.; Sharma, Satyan; Ba?inskaja, Giedr?; Rehman, Michael; Juffer, André H.; Walther, Tobias C.; Lisby, Michael; Choudhary, Chunaram

2012-01-01

365

Lipolytic activity of Williopsis californica and Saccharomyces cerevisiae in extra virgin olive oil.  

PubMed

Inoculation trials performed with three strains of yeasts, isolated from extra virgin olive oil, Williopsis californica 1,639, Saccharomyces cerevisiae 1,525 and Candida boidinii 1,638, demonstrated that some yeast can lower the quality of the oil during storage. Laboratory tests highlighted a substantial increase in the total diglycerides and free fatty acids in the samples of oil inoculated with the lipase-producing strains of yeasts, W. californica 1,639 and S. cerevisiae 1,525, while in the samples of oil inoculated with the lipase-negative strain C. boidinii 1,638 no differences were found in respect to the uninoculated control. The acidity of the extra virgin olive oil, inoculated with the lipase-producing strains W. californica 1,639 and S. cerevisiae 1,525, during 2 weeks of incubation at 30 degrees C increased respectively from 0.62% to 1.50 and 1.62%, exceeding the limit of 0.8% established by current regulations for this commercial category of olive oil, while in the oil inoculated with the lipase-negative strain and in the uninoculated control, the acidity remained constant throughout. Furthermore, the two strains of lipase-producing yeasts also increased the concentration of the 1.3-diglyceride isomer in the oil lowering the values of the total 1.2-diglycerides/total 1.3-diglycerides ratio considered to be an important index of quality for an extra virgin olive oil. The lipolytic activity of lipase-producing strains W. californica 1,639 and S. cerevisiae 1,525 showed an optimum pH of 6 and 7.5 and an optimum temperature of 20 degrees C and 30 degrees C respectively. Nevertheless, the lipolytic activity was negatively influenced by glucose and polyphenols when the concentration was higher than 0.25% and 0.4% (wt/vol) respectively. PMID:16271789

Ciafardini, G; Zullo, B A; Cioccia, G; Iride, A

2006-03-01

366

Glycolic acid production in the engineered yeasts Saccharomyces cerevisiae and Kluyveromyces lactis  

PubMed Central

Background Glycolic acid is a C2 hydroxy acid that is a widely used chemical compound. It can be polymerised to produce biodegradable polymers with excellent gas barrier properties. Currently, glycolic acid is produced in a chemical process using fossil resources and toxic chemicals. Biotechnological production of glycolic acid using renewable resources is a desirable alternative. Results The yeasts Saccharomyces cerevisiae and Kluyveromyces lactis are suitable organisms for glycolic acid production since they are acid tolerant and can grow in the presence of up to 50 g l-1 glycolic acid. We engineered S. cerevisiae and K. lactis for glycolic acid production using the reactions of the glyoxylate cycle to produce glyoxylic acid and then reducing it to glycolic acid. The expression of a high affinity glyoxylate reductase alone already led to glycolic acid production. The production was further improved by deleting genes encoding malate synthase and the cytosolic form of isocitrate dehydrogenase. The engineered S. cerevisiae strain produced up to about 1 g l-1 of glycolic acid in a medium containing d-xylose and ethanol. Similar modifications in K. lactis resulted in a much higher glycolic acid titer. In a bioreactor cultivation with d-xylose and ethanol up to 15 g l-1 of glycolic acid was obtained. Conclusions This is the first demonstration of engineering yeast to produce glycolic acid. Prior to this work glycolic acid production through the glyoxylate cycle has only been reported in bacteria. The benefit of a yeast host is the possibility for glycolic acid production also at low pH, which was demonstrated in flask cultivations. Production of glycolic acid was first shown in S. cerevisiae. To test whether a Crabtree negative yeast would be better suited for glycolic acid production we engineered K. lactis in the same way and demonstrated it to be a better host for glycolic acid production. PMID:24053654

2013-01-01

367

Metabolic pathway engineering for fatty acid ethyl ester production in Saccharomyces cerevisiae using stable chromosomal integration.  

PubMed

Fatty acid ethyl esters are fatty acid derived molecules similar to first generation biodiesel (fatty acid methyl esters; FAMEs) which can be produced in a microbial cell factory. Saccharomyces cerevisiae is a suitable candidate for microbial large scale and long term cultivations, which is the typical industrial production setting for biofuels. It is crucial to conserve the metabolic design of the cell factory during industrial cultivation conditions that require extensive propagation. Genetic modifications therefore have to be introduced in a stable manner. Here, several metabolic engineering strategies for improved production of fatty acid ethyl esters in S. cerevisiae were combined and the genes were stably expressed from the organisms' chromosomes. A wax ester synthase (ws2) was expressed in different yeast strains with an engineered acetyl-CoA and fatty acid metabolism. Thus, we compared expression of ws2 with and without overexpression of alcohol dehydrogenase (ADH2), acetaldehyde dehydrogenase (ALD6) and acetyl-CoA synthetase (acs SE (L641P) ) and further evaluated additional overexpression of a mutant version of acetyl-CoA decarboxylase (ACC1 (S1157A,S659A) ) and the acyl-CoA binding protein (ACB1). The combined engineering efforts of the implementation of ws2, ADH2, ALD6 and acs SE (L641P) , ACC1 (S1157A,S659A) and ACB1 in a S. cerevisiae strain lacking storage lipid formation (are1?, are2?, dga1? and lro1?) and ?-oxidation (pox1?) resulted in a 4.1-fold improvement compared with sole expression of ws2 in S. cerevisiae. PMID:25422103

de Jong, Bouke Wim; Shi, Shuobo; Valle-Rodríguez, Juan Octavio; Siewers, Verena; Nielsen, Jens

2015-03-01

368

A genetic overhaul of Saccharomyces cerevisiae 424A(LNH-ST) to improve xylose fermentation.  

PubMed

Robust microorganisms are necessary for economical bioethanol production. However, such organisms must be able to effectively ferment both hexose and pentose sugars present in lignocellulosic hydrolysate to ethanol. Wild type Saccharomyces cerevisiae can rapidly ferment hexose, but cannot ferment pentose sugars. Considerable efforts were made to genetically engineer S. cerevisiae to ferment xylose. Our genetically engineered S cerevisiae yeast, 424A(LNH-ST), expresses NADPH/NADH xylose reductase (XR) that prefer NADPH and NAD(+)-dependent xylitol dehydrogenase (XD) from Pichia stipitis, and overexpresses endogenous xylulokinase (XK). This strain is able to ferment glucose and xylose, as well as other hexose sugars, to ethanol. However, the preference for different cofactors by XR and XD might lead to redox imbalance, xylitol excretion, and thus might reduce ethanol yield and productivity. In the present study, genes responsible for the conversion of xylose to xylulose with different cofactor specificity (1) XR from N. crassa (NADPH-dependent) and C. parapsilosis (NADH-dependent), and (2) mutant XD from P. stipitis (containing three mutations D207A/I208R/F209S) were overexpressed in wild type yeast. To increase the NADPH pool, the fungal GAPDH enzyme from Kluyveromyces lactis was overexpressed in the 424A(LNH-ST) strain. Four pentose phosphate pathway (PPP) genes, TKL1, TAL1, RKI1 and RPE1 from S. cerevisiae, were also overexpressed in 424A(LNH-ST). Overexpression of GAPDH lowered xylitol production by more than 40%. However, other strains carrying different combinations of XR and XD, as well as new strains containing the overexpressed PPP genes, did not yield any significant improvement in xylose fermentation. PMID:20714780

Bera, Aloke K; Ho, Nancy W Y; Khan, Aftab; Sedlak, Miroslav

2011-05-01

369

Evaluation of Saccharomyces cerevisiae as an antiaflatoxicogenic agent in broiler feedstuffs.  

PubMed

Aflatoxins (AF) are the most important mycotoxins produced by toxigenic strains of various Aspergillus spp. Biological decontamination of mycotoxins using microorganisms is a well-known strategy for the management of mycotoxins in feeds. Saccharomyces cerevisiae strains have been reported to bind aflatoxin B1 (AFB1). The aim of this study was to evaluate the ability of S. cerevisiae CECT 1891 in counteracting the deleterious effects of AFB1 in broiler chicks. Experimental aflatoxicosis was induced in 6-d-old broilers by feeding them 1.2 mg of AFB1/kg of feed for 3 wk, and the yeast strain was administrated in feed (10(10) cells/kg), in the drinking water (5 × 10(9) cells/L), or a combination of both treatments. A total of 160 chicks were randomly divided into 8 treatments (4 repetitions per treatment). Growth performance was measured weekly from d 7 to 28, and serum biochemical parameters, weights, and histopathological examination of livers were determined at d 28. The AFB1 significantly decreased the BW gain, feed intake, and impaired feed conversion rate. Moreover, AFB1 treatment decreased serum protein concentration and increased liver damage. The addition of S. cerevisiae strain to drinking water, to diets contaminated with AFB1, showed a positive protection effect on the relative weight of the liver, histopathology, and biochemical parameters. Furthermore, dietary addition of the yeast strain to drinking water alleviated the negative effects of AFB1 on growth performance parameters. In conclusion, this study suggests that in feed contaminated with AFB1, the use of S. cerevisiae is an alternative method to reduce the adverse effects of aflatoxicosis. Thus, apart from its excellent nutritional value, yeast can also be used as a mycotoxin adsorbent. PMID:23687163

Pizzolitto, R P; Armando, M R; Salvano, M A; Dalcero, A M; Rosa, C A

2013-06-01

370

Ethanol production from nonsterilized carob pod extract by free and immobilized Saccharomyces cerevisiae cells using fed-batch culture  

SciTech Connect

The production of ethanol from carob pod extract by free and immobilized Saccharomyces cerevisiae cells in batch and fed-batch culture was investigated. Fed-batch culture proved to be a better fermentation system for the production of ethanol than batch culture. In fed-batch culture, both free and immobilized S. cerevisiae cells gave the same maximum concentration of final ethanol at an initial sugar concentration of 300 g/L and F = 167 mL/h. The maximum ethanol productivity was obtained with both free and immobilized cells at a substrate concentration of 300 g/L and F = 334 mL/h. In repeated fed-batch culture, immobilized S. cerevisiae cells gave a higher overall ethanol concentration compared with the free cells. The immobilized S. cerevisiae cells in Ca-alginate beads retained their ability to produce ethanol for 10 days.

Roukas, T. (Aristotelian Univ. of Thessaloniki (Greece). Dept. of Food Science and Technology)

1994-02-05

371

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

PubMed Central

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, the promoter controlling expression of BMRF1, which encodes diffuse early antigen, EA-D. These observations indicate that neither mammalian-specific nor virally encoded coactivators are obligatory for ZEBRA to stimulate expression from these two promoters. Zp was also strongly activated by endogenous yeast factors. EAp was not activated by yeast factors. The results show that in S. cerevisiae and in B cells, ZEBRA dominates the response of EAp; ZEBRA plus endogenous cell factors activate Zp. PMID:7933154

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

1994-01-01

372

The Roles of Monomeric GTP-Binding Proteins in Macroautophagy in Saccharomyces cerevisiae  

PubMed Central

Autophagy is a cellular degradation process that sequesters components into a double-membrane structure called the autophagosome, which then fuses with the lysosome or vacuole for hydrolysis and recycling of building blocks. Bulk phase autophagy, also known as macroautophagy, controlled by specific Atg proteins, can be triggered by a variety of stresses, including starvation. Because autophagy relies extensively on membrane traffic to form the membranous structures, factors that control membrane traffic are essential for autophagy. Among these factors, the monomeric GTP-binding proteins that cycle between active and inactive conformations form an important group. In this review, we summarize the functions of the monomeric GTP-binding proteins in autophagy, especially with reference to experiments in Saccharomyces cerevisiae. PMID:25302616

Yang, Shu; Rosenwald, Anne G.

2014-01-01

373

Permeabilization of yeast Saccharomyces cerevisiae cell walls using nanosecond high power electrical pulses  

NASA Astrophysics Data System (ADS)

The electrical field-induced changes of the yeast Saccharomyces cerevisiae cells permeabilization to tetraphenylphosphonium (TPP+) ions were studied using square-shaped, nanosecond duration high power electrical pulses. It was obtained that pulses having durations ranging from 10 ns to 60 ns, and generating electric field strengths up to 190 kV/cm significantly (up to 65 times) increase the absorption rate of TPP+ ions without any detectible influence on the yeast cell viability. The modelling of the TPP+ absorption process using a second order rate equation demonstrates that depending on the duration of the pulses, yeast cell clusters of different sizes are homogeniously permeabilized. It was concluded, that nanosecond pulse-induced permeabilization can be applied to increase the operational speed of whole cell biosensors.

Stirke, A.; Zimkus, A.; Balevicius, S.; Stankevic, V.; Ramanaviciene, A.; Ramanavicius, A.; Zurauskiene, N.

2014-12-01

374

D-Lactate Production as a Function of Glucose Metabolism in Saccharomyces cerevisiae  

PubMed Central

Methylglyoxal, a reactive, toxic dicarbonyl, is generated by the spontaneous degradation of glycolytic intermediates. Methylglyoxal can form covalent adducts with cellular macromolecules, potentially disrupting cellular function. We performed experiments using the model organism Saccharomyces cerevisiae grown in media containing low, moderate, and high glucose concentrations to determine the relationship between glucose consumption and methylglyoxal metabolism. Normal growth experiments and glutathione depletion experiments showed that metabolism of methylglyoxal by log-phase yeast cultured aerobically occurred primarily through the glyoxalase pathway. Growth in high-glucose media resulted in increased generation of the methylglyoxal metabolite D-lactate and overall lower efficiency of glucose utilization as measured by growth rates. Cells grown in high-glucose media maintained higher glucose uptake flux than cells grown in moderate-glucose or low-glucose media. Computational modeling showed that increased glucose consumption may impair catabolism of triose phosphates as a result of an altered NAD+/NADH ratio. PMID:23361949

Stewart, Benjamin J.; Navid, Ali; Kulp, Kristen S.; Knaack, Jennifer L. S.; Bench, Graham

2013-01-01

375

Photocatalytic activity of biogenic silver nanoparticles synthesized using yeast (Saccharomyces cerevisiae) extract  

NASA Astrophysics Data System (ADS)

Synthesis of metallic and semiconductor nanoparticles through physical and chemical route is quiet common but biological synthesis procedures are gaining momentum due to their simplicity, cost-effectivity and eco-friendliness. Here, we report green synthesis of silver nanoparticles from aqueous solution of silver salts using yeast (Saccharomyces cerevisiae) extract. The nanoparticles formation was gradually investigated by UV-Vis spectrometer. X-ray diffraction analysis was done to identify different phases of biosynthesized Ag nanoparticles. Transmission electron microscopy was performed to study the particle size and morphology of silver nanoparticles. Fourier transform infrared spectroscopy of the nanoparticles was performed to study the role of biomolecules capped on the surface of Ag nanoparticles during interaction. Photocatalytic activity of these biosynthesized nanoparticles was studied using an organic dye, methylene blue under solar irradiation and these nanoparticles showed efficacy in degrading the dye within a few hours of exposure.

Roy, Kaushik; Sarkar, C. K.; Ghosh, C. K.

2014-12-01

376

The untranslated leader of nuclear COX4 gene of Saccharomyces cerevisiae contains an intron.  

PubMed Central

The nuclear gene for subunit IV of cytochrome oxidase (COX4) in Saccharomyces cerevisiae contains a 342 bp intron which is contained entirely within the 5' leader of the message. Splicing of the intron results in removal of several small open reading frames; subsequently, the COX4 AUG becomes the 5' proximal initiation codon. A strain with an rna2- mutation fails to splice mRNA efficiently at restrictive temperature and was used to map the intron splice junctions by RNase protection. Two major mRNA initiation sites were mapped by primer extension of synthetic oligodeoxynucleotides. The splice junctions and internal TACTAAC box conform to consensus sequences previously determined from other yeast introns. One gene for subunit V of cytochrome oxidase (COX5b) has also been shown to contain an intron. The significance of introns in two nuclear genes encoding subunits of cytochrome oxidase is discussed. Images PMID:3033605

Schneider, J C; Guarente, L

1987-01-01

377

Ctk1 function is necessary for full translation initiation activity in Saccharomyces cerevisiae.  

PubMed

Translation is a fundamental and highly regulated cellular process. Previously, we reported that the kinase and transcription elongation factor Ctk1 increases fidelity during translation elongation in Saccharomyces cerevisiae. Here, we show that loss of Ctk1 function also affects the initiation step of translation. Translation active extracts from Ctk1 depleted cells show impaired translation activity of capped, but not CrPV IRES containing mRNA reporters. Furthermore, the formation of 80S initiation complexes is decreased, which is probably due to reduced subunit joining. In addition, we determined the changes in the phosphorylation pattern of a ribosome enriched fraction after depletion of Ctk1. Thus, we provide a catalogue of phosphoproteomic changes dependent on Ctk1. Taken together, our data suggest a stimulatory function of Ctk1 in 80S formation during translation initiation. PMID:25416238

Coordes, Britta; Brünger, Katharina M; Burger, Kaspar; Soufi, Boumediene; Horenk, Juliane; Eick, Dirk; Olsen, Jesper V; Sträßer, Katja

2014-11-21

378

Isolation and characterization of temperature-sensitive mak mutants of Saccharomyces cerevisiae.  

PubMed Central

The K1 killer plasmid of Saccharomyces cerevisiae is a 1.5-megadalton linear double-stranded ribonucleic acid molecule. Using simplified screening and complementation procedures, we have isolated mutants in three chromosomal genes that are temperature sensitive for killer plasmid maintenance or replication. One of these genes, mak28-1, was located on chromosome X. Two of the temperature-sensitive mutants rapidly lost the wild-type killer plasmid of A364A during spore germination and outgrowth at nonpermissive temperatures, but during vegetative growth, they only lowered the plasmid copy number. These two mutants did not lose two other wild-type K1 killer plasmids, indicating a heterogeneity of the killer plasmids in laboratory yeast strains. Images PMID:7002907

Guerry-Kopecko, P; Wickner, R B

1980-01-01

379

Genetic regulation of differentiation towards meiosis in the yeast Saccharomyces cerevisiae.  

PubMed

Normally, meiosis and sporulation in Saccharomyces cerevisiae occur only in diploid strains and only when the cells are exposed to starvation conditions. Diploidy is determined by the mating-type system (the genes MAT, RME1, IME1), whereas the starvation signal is transmitted through the adenylate cyclase - protein kinase pathway (the genes CDC25, RAS2, CDC35 (CYR1), BCY1, TPK1, TPK2, TPK3). The two regulatory pathways converge at the gene IME1, which is a positive regulator of meiosis and whose early expression in sporulating cells correlates with the initiation of meiosis. Sites upstream (5') of IME1 appear to mediate in the repression of the gene by repressors originating from both the mating-type and the cyclase--kinase pathways. PMID:2687111

Simchen, G; Kassir, Y

1989-01-01

380

The immunosuppressant SR 31747 blocks cell proliferation by inhibiting a steroid isomerase in Saccharomyces cerevisiae.  

PubMed Central

SR 31747 is a novel immunosuppressant agent that arrests cell proliferation in the yeast Saccharomyces cerevisiae, SR 31747-treated cells accumulate the same aberrant sterols as those found in a mutant impaired in delta 8- delta 7-sterol isomerase. Sterol isomerase activity is also inhibited by SR 31747 in in vitro assays. Overexpression of the sterol isomerase-encoding gene, ERG2, confers enhanced SR resistance. Cells growing anaerobically on ergosterol-containing medium are not sensitive to SR. Disruption of the sterol isomerase-encoding gene is lethal in cells growing in the absence of exogenous ergosterol, except in SR-resistant mutants lacking either the SUR4 or the FEN1 gene product. The results suggest that sterol isomerase is the target of SR 31747 and that both the SUR4 and FEN1 gene products are required to mediate the proliferation arrest induced by ergosterol depletion. PMID:8649379

Silve, S; Leplatois, P; Josse, A; Dupuy, P H; Lanau, C; Kaghad, M; Dhers, C; Picard, C; Rahier, A; Taton, M; Le Fur, G; Caput, D; Ferrara, P; Loison, G

1996-01-01

381

Protective mechanisms against the antitumor agent bleomycin: lessons from Saccharomyces cerevisiae.  

PubMed

Bleomycin is a small glycopeptide antibiotic used in combination therapy for the treatment of a few types of human cancer. The antitumor effect of bleomycin is most likely caused by its ability to bind to DNA and induce the formation of toxic DNA lesions via a free radical reactive (Fe.bleomycin) complex. However, the chemotherapeutic potential of bleomycin is limited, as it causes pulmonary fibrosis and tumor resistance at high doses. The chemical structure and modes of action of bleomycin have been extensively studied and these provide a foundation towards improving the therapeutic value of the drug. This review provides a first account of the current state of knowledge of the cellular processes that can allow the yeast Saccharomyces cerevisiae to evade the lethal effects of bleomycin. This model organism is likely to provide rapid clues in our understanding of bleomycin resistance in tumor cells. PMID:12698269

Ramotar, Dindial; Wang, Huijie

2003-07-01

382

Iron Sensing and Regulation in Saccharomyces cerevisiae: Ironing Out the Mechanistic Details  

PubMed Central

Regulation of iron metabolism in Saccharomyces cerevisiae is achieved at the transcriptional level by low (Aft1 and Aft2) and high iron-sensing (Yap5) transcription factors, and at the post-transcriptional level by mRNA-binding proteins (Cth1 and Cth2). In this review we highlight recent studies unveiling the critical role that iron-sulfur clusters play in control of Aft1/2 and Yap5 activity, as well as the complex relationship between iron homeostasis and thiol redox metabolism. In addition, new insights into the localization and regulation of Cth1/Cth2 have added another layer of complexity to the cell’s adaptation to iron deficiency. Finally, biophysical studies on subcellular iron speciation changes in response to environmental and genetic factors have further illuminated the elaborate control mechanisms required to manage iron bioavailability in the cell. PMID:23962819

Outten, Caryn E.; Albetel, Angela-Nadia

2013-01-01

383

Improvement of L-Arabinose Fermentation by Modifying the Metabolic Pathway and Transport in Saccharomyces cerevisiae  

PubMed Central

The L-arabinose utilization pathway was established in Saccharomyces cerevisiae, by expressing the codon-optimized araA, araB, and araD genes of Lactobacillus plantarum. After overexpressing the TAL1, TKL1, RPE1, RKI1, and GAL2 genes and adaptive evolution, the L-arabinose utilization of the recombinant strain became efficient. The resulting strain displayed a maximum specific growth rate of 0.075?h?1, a maximum specific L-arabinose consumption rate of 0.61?g?h?1?g?1 dry cell weight, and a promising ethanol yield of 0.43?g?g?1 from L-arabinose fermentation. PMID:24195072

Wang, Chengqiang; Zhang, Yanyan

2013-01-01

384

Identification of DNA damage checkpoint-dependent protein interactions in Saccharomyces cerevisiae using quantitative mass spectrometry  

PubMed Central

Summary The DNA damage checkpoint (DDC) is an evolutionarily conserved signaling pathway that is crucial to maintain genomic integrity. In response to DNA damage, DDC kinases are rapidly activated and phosphorylate an elaborate network of substrates involved in multiple cellular processes. An important role of the DDC response is to assemble protein complexes. However, for most of the DDC substrates, how the DDC-dependent phosphorylation modulates their network of interactions remains to be established. Here, we present a protocol for the identification of DDC-dependent protein-protein interactions based on Stable Isotope Labeling of Amino acids in Cell culture (SILAC) followed by affinity-tagged protein purification and quantitative mass spectrometry analysis. Based on a model study using Saccharomyces cerevisiae, we provide a method that can be generally applied to study the role of kinases in mediating protein-protein interactions. PMID:24791994

Bastos de Oliveira, Francisco M.; Smolka, Marcus B.

2014-01-01

385

The Saccharomyces cerevisiae centromere protein Slk19p is required for two successive divisions during meiosis.  

PubMed Central

Meiotic cell division includes two separate and distinct types of chromosome segregation. In the first segregational event the sister chromatids remain attached at the centromere; in the second the chromatids are separated. The factors that control the order of chromosome segregation during meiosis have not yet been identified but are thought to be confined to the centromere region. We showed that the centromere protein Slk19p is required for the proper execution of meiosis in Saccharomyces cerevisiae. In its absence diploid cells skip meiosis I and execute meiosis II division. Inhibiting recombination does not correct this phenotype. Surprisingly, the initiation of recombination is apparently required for meiosis II division. Thus Slk19p appears to be part of the mechanism by which the centromere controls the order of meiotic divisions. PMID:10835382

Zeng, X; Saunders, W S

2000-01-01

386

Genetic determinants of the release of mannoproteins of enological interest by Saccharomyces cerevisiae.  

PubMed

Cell wall mannoproteins released by Saccharomyces cerevisiae during wine fermentation and aging have recently attracted the attention of enologists and researchers in enology due to their positive effect over a number of technological and quality properties of the wines, including protein and tartaric stability, aroma and color stability, astringency, mouthfeel, malolactic fermentation, or foam properties of sparkling wines. This work has investigated the effect of deletions involving genes related to cell wall biogenesis on the release of mannoproteins, as well as the effect of the released mannoproteins on wine protein stability. When available, the phenotypes have been studied in different genetic backgrounds, in haploid or diploid strains, and in homo- or heterozygosis. Strains deleted for GAS1, GPI7, or KNR4 release higher amounts of mannoproteins and polysaccharides to the medium. These increased amounts of mannoproteins and polysaccharides lead to a stronger stability of Sauvignon Blanc wines against protein haze. PMID:17147426

Gonzalez-Ramos, Daniel; Gonzalez, Ramon

2006-12-13

387

L-Asparagine auxotrophs of Saccharomyces cerevisiae: genetic and phenotypic characterization.  

PubMed Central

L-Asparagine auxotrophy in Saccharomyces cerevisiae is the result of mutation in each of two unlinked cistrons, ASN1 and ASN2. Mutation in only one of these cistrons yields growth indistinguishable from that of wild-type cells under a variety of nutritional stresses. Relatively high concentrations of L-asparagine are required to permit maximal growth of the auxotrophs, and the amino acid requirement cannot be satisfied by a variety of other amino acids that serve as nitrogen sources for cell growth. Although reversion of the mutations can occur, haploid populations of cells containing only low frequencies of prototrophs can be maintained easily. In diploid cells heteroallelic for certain combinations of alleles of the two genes, mitotic recombination gives rise to prototrophic cells that accumulate to high frequency in populations of the cells. PMID:348677

Jones, G E

1978-01-01

388

Genetic and physiological relationships between L-asparaginase I and asparaginase II in Saccharomyces cerevisiae.  

PubMed Central

The cistron that codes for L-asparaginase I in Saccharomyces cerevisiae (aspl) is not genetically linked to either of the cistrons coding for expression of asparaginase II (asp2 and asp3). Cells containing different combinations of theses enzymes grow at different rates in media in which L-asparagine or D-asparagine is the only source of nitrogen for cell replication. Cells lacking L-asparaginase I but possessing asparaginase II grow more rapidly in medium containing D-asparagine as a nitrogen source than cells containing both enzymes, even though D-asparagine is not a substrate of L-asparaginase I. These results indicate that L-asparaginase I and asparaginase II interact in some way to regulate the utilization of asparagine as a nitrogen source for cell growth. PMID:323221

Jones, G E

1977-01-01

389

Thi20, a remarkable enzyme from Saccharomyces cerevisiae with dual thiamin biosynthetic and degradation activities.  

PubMed

Saccharomyces cerevisiae Thi20 is a fusion protein with homology to Bacillus subtilis ThiD and TenA. The N-terminus of Thi20 has significant sequence homology to B. subtilis ThiD, while the C-terminus has homology to B. subtilis TenA. Incubation of Thi20 with thiamin reveals that it has thiaminase II activity, in addition, incubation of Thi20 with HMP (4-amino-2-methyl-5-hydroxymethylpyrimidine) and ATP reveals that it has HMP kinase and HMP-P (4-amino-2-methyl-5-hydroxymethylpyrimidine phosphate) kinase activity. This demonstrates that Thi20 is a trifunctional protein with thiamin biosynthetic and degradative activity. PMID:15967475

Haas, Amy L; Laun, Nathan P; Begley, Tadhg P

2005-08-01

390

Fatty Acid-Derived Biofuels and Chemicals Production in Saccharomyces cerevisiae  

PubMed Central

Volatile energy costs and environmental concerns have spurred interest in the development of alternative, renewable, sustainable, and cost-effective energy resources. Environment-friendly processes involving microbes can be used to synthesize advanced biofuels. These fuels have the potential to replace fossil fuels in supporting high-power demanding machinery such as aircrafts and trucks. From an engineering perspective, the pathway for fatty acid biosynthesis is an attractive route for the production of advanced fuels such as fatty acid ethyl esters, fatty alcohols, and alkanes. The robustness and excellent accessibility to molecular genetics make the yeast Saccharomyces cerevisiae a suitable host for the purpose of bio-manufacturing. Recent advances in metabolic engineering, as well as systems and synthetic biology, have now provided the opportunity to engineer yeast metabolism for the production of fatty acid-derived fuels and chemicals. PMID:25225637

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

2014-01-01

391

Fatty Acid-Derived Biofuels and Chemicals Production in Saccharomyces cerevisiae.  

PubMed

Volatile energy costs and environmental concerns have spurred interest in the development of alternative, renewable, sustainable, and cost-effective energy resources. Environment-friendly processes involving microbes can be used to synthesize advanced biofuels. These fuels have the potential to replace fossil fuels in supporting high-power demanding machinery such as aircrafts and trucks. From an engineering perspective, the pathway for fatty acid biosynthesis is an attractive route for the production of advanced fuels such as fatty acid ethyl esters, fatty alcohols, and alkanes. The robustness and excellent accessibility to molecular genetics make the yeast Saccharomyces cerevisiae a suitable host for the purpose of bio-manufacturing. Recent advances in metabolic engineering, as well as systems and synthetic biology, have now provided the opportunity to engineer yeast metabolism for the production of fatty acid-derived fuels and chemicals. PMID:25225637

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

2014-01-01

392

Involvement of the Saccharomyces cerevisiae hydrolase Ldh1p in lipid homeostasis.  

PubMed

Here, we report the functional characterization of the newly identified lipid droplet hydrolase Ldh1p. Recombinant Ldh1p exhibits esterase and triacylglycerol lipase activities. Mutation of the serine in the hydrolase/lipase motif GXSXG completely abolished esterase activity. Ldh1p is required for the maintenance of a steady-state level of the nonpolar and polar lipids of lipid droplets. A characteristic feature of the Saccharomyces cerevisiae ?ldh1 strain is the appearance of giant lipid droplets and an excessive accumulation of nonpolar lipids and phospholipids upon growth on medium containing oleic acid as a sole carbon source. Ldh1p is thought to play a role in maintaining the lipid homeostasis in yeast by regulating both phospholipid and nonpolar lipid levels. PMID:21478434

Debelyy, Mykhaylo O; Thoms, Sven; Connerth, Melanie; Daum, Günther; Erdmann, Ralf

2011-06-01

393

Evaluation of molecular typing techniques to assign genetic diversity among Saccharomyces cerevisiae strains.  

PubMed Central

Discrimination of strains within the species Saccharomyces cerevisiae was demonstrated by the use of four different techniques to type 15 strains isolated from spoiled wine and beer. Random amplified polymorphic DNA with specific oligonucleotides and PCR fingerprinting with the microsatellite oligonucleotide primers (GAC)5 and (GTG)5 enabled discrimination between the strains tested. Additionally, restriction enzyme analysis, with TaqI and MseI, of PCR-amplified fragments from the complete internal transcribed spacer and nontranscribed spacer, both present in the rRNA-encoding gene cluster, proved to be suitable for generating intraspecies-specific patterns. Random amplified polymorphic DNA with primers 24 and OPA-11 and PCR fingerprinting with primer (GTG)5 appeared to generate the highest degree of diversity. However, the results indicated that there was no single PCR-mediated typing technique enabling discrimination on the strain level. Discrimination of each individual strain was nevertheless possible by combining the results obtained with all typing techniques. PMID:8572710

Baleiras Couto, M M; Eijsma, B; Hofstra, H; Huis in't Veld, J H; van der Vossen, J M

1996-01-01

394

Accumulation of 2'-O-methylguanosine deficient tRNATrp in tryptophan limited Saccharomyces cerevisiae.  

PubMed

Saccharomyces cerevisiae synthesizes one major tryptophan transfer ribonucleic acid (tRNATrp) species (isoacceptor A) carrying characteristic base modifications. Under tryptophan limited growth conditions wild-type strain X2180-1A exhibited a second important tRNATrp species (isoacceptor B). The total amount of tRNATrp, approximately 2.5 pmol (mg dry wt)-1, stayed essentially constant during amino acid shift-down experiments. The amount of isoacceptor B relative to total tRNATrp was 10 to 15% during amino acid sufficient exponential growth conditions, but increased during tryptophan limitation three- to four-fold. Analysis of the base compositions showed that isoacceptor B differed from isoacceptor A in one respect only: 2'-O-methylguanosine, a modified guanosine base occurring at position 17 of the major isoacceptor A tRNATrp, was not detectable in hydrolysates of purified isoacceptor B. The biological significance of isoacceptor B is discussed. PMID:6759616

Stäheli, P; Agris, P F; Niederberger, P; Gehrke, C W; Hütter, R

1982-11-01

395

Importance of the Sgs1 helicase activity in DNA repair of Saccharomyces cerevisiae.  

PubMed

The Saccharomyces cerevisiae Sgs1 protein, together with Schizosaccharomyces pombe Rqh1 and the human Bloom and Werner proteins, is a DNA helicase of the Escherichia coli RecQ family. Mutation of SGS1 causes premature aging in yeast cells, including the accumulation of extrachromosomal rDNA circles. We have recently shown that Sgs1p interacts with the DNA repair Rad16p protein and is epistatic to Rad16p for UVC, 4-NQO and H2O2 lesions. Therefore we tested sgs1 strains containing mutations in the helicase and C-terminal domains. We demonstrate here that the helicase activity of the Sgs1 is important for most elements of the sgs1 mutation phenotype, including sensitivity to UVC, 4-NQO, H2O2, MMS and hydroxyurea. PMID:10743562

Saffi, J; Pereira, V R; Henriques, J A

2000-02-01

396

Identification and characterization of a functional Candida albicans homolog of the Saccharomyces cerevisiae TCO89 gene.  

PubMed

As one of the components of target of rapamycin complex 1 (TORC1), ScTco89p is involved in rapamycin sensitivity and cellular integrity in Saccharomyces cerevisiae. Here we provide evidence showing that deletion of ScTCO89 causes yeast cells to be hypersensitive to salt stress in a high osmolarity glycerol pathway-independent fashion. In addition, we have identified and characterized a functional Candida albicans homolog (CaTCO89) of ScTCO89, which encodes a protein of 708 amino acids that shows overall 15% identity with ScTco89p at the amino acid level. However, CaTCO89 could complement the functions of ScTCO89 in rapamycin sensitivity, salt tolerance, and cellular integrity. Candida albicans cells disrupted for CaTCO89 are also sensitive to rapamycin and lithium salt, but not susceptible to challenges to cellular integrity. PMID:17298473

Zheng, Changlong; Yan, Zhihui; Liu, Wei; Jiang, Linghuo

2007-06-01

397

Effects of ubiquinone derivatives on the mitochondrial unselective channel of Saccharomyces cerevisiae.  

PubMed

Ubiquinone derivatives modulate the mammalian mitochondrial Permeability Transition Pore (PTP). Yeast mitochondria harbor a similar structure: the respiration- and ATP-induced Saccharomyces cerevisiae Mitochondrial Unselective Channel ( Sc MUC). Here we show that decylubiquinone, a well-characterized inhibitor of the PTP, suppresses Sc MUC opening in diverse strains and independently of respiratory chain modulation or redox-state. We also found that naturally occurring derivatives such as hexaprenyl and decaprenyl ubiquinones lacked effects on the Sc MUC. The PTP-inactive ubiquinone 5 (Ub5) promoted the Sc MUC-independent activation of the respiratory chain in most strains tested. In an industrial strain however, Ub5 blocked the protection elicited by dUb. The results indicate the presence of a ubiquinone-binding site in the Sc MUC. PMID:25465614

Gutiérrez-Aguilar, Manuel; López-Carbajal, Helga M; Uribe-Alvarez, Cristina; Espinoza-Simón, Emilio; Rosas-Lemus, Mónica; Chiquete-Félix, Natalia; Uribe-Carvajal, Salvador

2014-12-01

398

Glutathione peroxidase 2 in Saccharomyces cerevisiae is distributed in mitochondria and involved in sporulation.  

PubMed

Gpx2, one of three glutathione peroxidase homologs (Gpx1, Gpx2, and Gpx3) in Saccharomyces cerevisiae, is an atypical 2-Cys peroxiredoxin that prefers to use thioredoxin as a reducing agent in vitro. Despite Gpx2 being an antioxidant, no obvious phenotype of gpx2? mutant cells in terms of oxidative stress has yet been found. To gain a clue as to Gpx2's physiological function in vivo, here we identify its intracellular distribution. Gpx2 was found to exist in the cytoplasm and mitochondria. In mitochondria, Gpx2 was associated with the outer membrane of the cytoplasmic-side, as well as the inner membrane of the matrix-side. The redox state of the mitochondrial Gpx2 was regulated by Trx1 and Trx2 (cytoplasmic thioredoxin), and by Trx3 (mitochondrial matrix thioredoxin). In addition, we found that the disruption of GPX2 reduced the sporulation efficiency of diploid cells. PMID:21763276

Ukai, Yuuta; Kishimoto, Tomoyuki; Ohdate, Takumi; Izawa, Singo; Inoue, Yoshiharu

2011-08-01

399

Allelism of IMP1 and GAL2 genes of Saccharomyces cerevisiae.  

PubMed Central

Cloning and characterization of the previously described Saccharomyces cerevisiae IMP1 gene, which was assumed to be a nuclear determinant involved in the nucleomitochondrial control of the utilization of galactose, demonstrate allelism to the GAL2 gene. Galactose metabolism does not necessarily involve the induction of the specific transport system coded by GAL2/IMP1, because a null mutant takes up galactose and grows on it. Data on galactose uptake are presented, and the dependence on ATP for constitutive and inducible galactose transport is discussed. These results can account for the inability of imp1/gal2 mutants to grow on galactose in a respiration-deficient background. Under these conditions, uptake was affected at the functional level but not at the biosynthetic level. Images PMID:1577709

Donnini, C; Lodi, T; Ferrero, I; Algeri, A; Puglisi, P P

1992-01-01

400

Freeze-dried Saccharomyces cerevisiae cells immobilized on potato pieces for low-temperature winemaking.  

PubMed

A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on potato pieces. This biocatalyst was subjected to freeze-drying, and the effect of several protective agents and storage at 5 °C, up to 9 months, on viability and fermentative activity of yeasts cells were studied. From several protective agents tested, sodium glutamate preserved the viability of immobilized yeast cells at high levels even after 9-month storage. The freeze-drying biocatalyst was used for repeated batch fermentations of grape must at low temperatures until 5 °C. The produced wines analyzed for volatile byproducts by GC and GC/MS and the results showed that the freeze-dried biocatalysts, with sodium glutamate as protectant, produced wines with higher formation of esters than free cells and having at least similar aromatic profile to those produced by wet biocatalysts. PMID:24699815

Kandylis, Panagiotis; Dimitrellou, Dimitra; Lymnaiou, Paraskevi; Koutinas, Athanasios A

2014-06-01

401

Saccharomyces cerevisiae Mixed Culture of Blackberry (Rubus ulmifolius L.) Juice: Synergism in the Aroma Compounds Production  

PubMed Central

Blackberry (Rubus sp.) juice was fermented using four different strains of Saccharomyces cerevisiae (Vitilevure-CM4457, Enoferm-T306, ICV-K1, and Greroche Rhona-L3574) recognized because of their use in the wine industry. A medium alcoholic graduation spirit (<6°GL) with potential to be produced at an industrial scale was obtained. Alcoholic fermentations were performed at 28°C, 200?rpm, and noncontrolled pH. The synergistic effect on the aromatic compounds production during fermentation in mixed culture was compared with those obtained by monoculture and physic mixture of spirits produced in monoculture. The aromatic composition was determined by HS-SPME-GC. The differences in aromatic profile principally rely on the proportions in aromatic compounds and not on the number of those compounds. The multivariance analysis, principal component analysis (PCA), and factorial discriminant analysis (DFA) permit to demonstrate the synergism between the strains. PMID:25506606

Ragazzo-Sánchez, Juan Arturo; Ortiz-Basurto, Rosa Isela; Luna-Solano, Guadalupe; Calderón-Santoyo, Montserrat

2014-01-01

402

Crystallization and preliminary X-ray diffraction analysis of the invertase from Saccharomyces cerevisiae  

PubMed Central

Saccharomyces cerevisiae invertase (ScInv) is an enzyme encoded by the SUC2 gene that releases ?-fructose from the nonreducing termini of various ?-­d-fructofuranoside substrates. Its ability to produce 6-kestose by transglycosylation makes this enzyme an interesting research target for applications in industrial biotechnology. The native enzyme, which presents a high degree of oligomerization, was crystallized by vapour-diffusion methods. The crystals belonged to space group P3121, with unit-cell parameters a = 268.6, b = 268.6, c = 224.4?Å. The crystals diffracted to 3.3?Å resolution and gave complete data sets using a synchrotron X-ray source. PMID:23192042

Sainz-Polo, M. Angela; Lafraya, Alvaro; Polo, Aitana; Marín-Navarro, Julia; Polaina, Julio; Sanz-Aparicio, Julia

2012-01-01

403

Saccharomyces cerevisiae Sin3p facilitates DNA double-strand break repair  

PubMed Central

There are two main pathways in eukaryotic cells for the repair of DNA double-strand breaks: homologous recombination and nonhomologous end joining. Because eukaryotic genomes are packaged in chromatin, these pathways are likely to require the modulation of chromatin structure. One way to achieve this is by the acetylation of lysine residues on the N-terminal tails of histones. Here we demonstrate that Sin3p and Rpd3p, components of one of the predominant histone deacetylase complexes of Saccharomyces cerevisiae, are required for efficient nonhomologous end joining. We also show that lysine 16 of histone H4 becomes deacetylated in the proximity of a chromosomal DNA double-strand break in a Sin3p-dependent manner. Taken together, these results define a role for the Sin3p/Rpd3p complex in the modulation of DNA repair. PMID:14711989

Jazayeri, Ali; McAinsh, Andrew D.; Jackson, Stephen P.

2004-01-01

404

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

PubMed Central

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

1996-01-01

405

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

PubMed

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

406

Addition of methionine and low cultivation temperatures increase palmitoleic acid production by engineered Saccharomyces cerevisiae.  

PubMed

Palmitoleic acid (POA) has recently gained attention for its health benefits and as a potential resource for industrial feedstock. This study focused on the use of Saccharomyces cerevisiae, which has a high POA content but low lipid content, for POA production. We created an oleaginous S. cerevisiae as a dga1 mutant overexpressing Dga1p lacking the N-terminal 29 amino acids (Dga1?Np). This was performed to further increase POA content in the oleaginous S. cerevisiae through optimization of culture conditions and genetic modifications. We found that high concentrations of methionine (2.0 g/l) increased POA production in a concentration-dependent way, while other amino acids such as cysteine, glycine, and glutamine showed no effect. It was not clear if the effect of methionine was mediated through S-adenosylmethionine, mainly because its addition did not increase POA content as did the addition of methionine. We increased POA content up to 55 % by incubation of the dga1 transformant in a medium containing 2 g/l methionine at lower than normal temperatures ranging from 20 to 25 °C. Cultivation at such temperatures increased dry cell weight, but did not affect the lipid content, thereby increasing total POA production. The effects of methionine and low temperatures (20-25 °C) on POA content were more apparent in the strains overexpressing Dga1?Np than those harboring empty vectors, which was consistent with the observation that POA was enriched in triacylglycerol. Overexpression of Ole1p, the enzyme responsible for POA production, did not increase POA content of the dga1 mutant overexpressing Dga1?Np, but increased that of the wild-type strain overexpressing Dga1?Np. The results suggested that genomic Ole1p in the dga1 mutant was active enough to achieve the optimal POA production under these conditions. Finally, the POA production by the S. cerevisiae transformant was increased 2.5-fold, which demonstrates that oleaginous S. cerevisiae is a potential source of POA. PMID:25267159

Kamisaka, Yasushi; Kimura, Kazuyoshi; Uemura, Hiroshi; Yamaoka, Masakazu

2015-01-01

407

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

PubMed

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

408

Utilization of Saccharomyces cerevisiae recombinant strain incapable of both ethanol and glycerol biosynthesis for anaerobic bioproduction.  

PubMed

The yeast Saccharomyces cerevisiae produces ethanol and glycerol as major unwanted byproducts, unless ethanol and glycerol are the target compounds. Minimizing the levels of these byproducts is important for bioproduction processes using yeast cells. In this study, we constructed a yeast strain in which both ethanol and glycerol production pathways were disrupted and examined its culture characteristics. In wild-type yeast strain, metabolic pathways that produce ethanol and glycerol play an important role in reoxidizing nicotinamide adenine dinucleotide (NADH) generated during glycolysis, particularly under anaerobic conditions. Strains in which both pathways were disrupted therefore failed to grow and consume glucose under anaerobic conditions. Introduction of desired metabolic reaction(s) coupled with NADH oxidation enabled the engineered strain to consume substrate and produce target compound(s). Here we introduced NADH-oxidization-coupled L-lactate production mechanisms into a yeast strain incapable of ethanol and glycerol biosynthesis, based on in silico simulation using a genome-scale metabolic model of S. cerevisiae. From the results of in silico simulation based on flux balance analysis, a feasible anaerobic non-growing metabolic state, in which L-lactate yield approached the theoretical maximum, was identified and this phenomenon was verified experimentally. The yeast strain incapable of both ethanol and glycerol biosynthesis is a potentially valuable host for bioproduction coupled with NADH oxidation under anaerobic conditions. PMID:23435983

Ida, Yoshihiro; Hirasawa, Takashi; Furusawa, Chikara; Shimizu, Hiroshi

2013-06-01

409

Recombinant Production of Human Aquaporin-1 to an Exceptional High Membrane Density in Saccharomyces cerevisiae  

PubMed Central

In the present paper we explored the capacity of yeast Saccharomyces cerevisiae as host for heterologous expression of human Aquaporin-1. Aquaporin-1 cDNA was expressed from a galactose inducible promoter situated on a plasmid with an adjustable copy number. Human Aquaporin-1 was C-terminally tagged with yeast enhanced GFP for quantification of functional expression, determination of sub-cellular localization, estimation of in vivo folding efficiency and establishment of a purification protocol. Aquaporin-1 was found to constitute 8.5 percent of total membrane protein content after expression at 15°C in a yeast host over-producing the Gal4p transcriptional activator and growth in amino acid supplemented minimal medium. In-gel fluorescence combined with western blotting showed that low accumulation of correctly folded recombinant Aquaporin-1 at 30°C was due to in vivo mal-folding. Reduction of the expression temperature to 15°C almost completely prevented Aquaporin-1 mal-folding. Bioimaging of live yeast cells revealed that recombinant Aquaporin-1 accumulated in the yeast plasma membrane. A detergent screen for solubilization revealed that CYMAL-5 was superior in solubilizing recombinant Aquaporin-1 and generated a monodisperse protein preparation. A single Ni-affinity chromatography step was used to obtain almost pure Aquaporin-1. Recombinant Aquaporin-1 produced in S. cerevisiae was not N-glycosylated in contrast to the protein found in human erythrocytes. PMID:23409185

Bomholt, Julie; Hélix-Nielsen, Claus; Scharff-Poulsen, Peter; Pedersen, Per Amstrup

2013-01-01

410

Evidence for Avt6 as a vacuolar exporter of acidic amino acids in Saccharomyces cerevisiae cells.  

PubMed

Here we examined the significance of Avt6, a vacuolar exporter of glutamate and aspartate suggested by the in vitro membrane vesicle experiment, in vacuolar compartmentalization of amino acids in Saccharomyces cerevisiae cells. Fluorescent microscopic observation of GFP-fused Avt6 revealed it to be exclusively localized to the vacuolar membrane, with the amount of Myc-tagged Avt6 significantly increased under nitrogen starvation. Glutamate uptake by cells was enhanced by deletion of the AVT6 gene, indicating indirect involvement of Avt6 in cellular glutamate accumulation. Differences in acidic amino acid content of both total and vacuolar fractions were insignificant between the parent and avt6Delta cells when cultured in nutrient-rich conditions. However, in nitrogen-starved conditions, the amount of glutamate and aspartate in the vacuolar fraction was notably increased in the avt6Delta cells. Avt6 is thus involved in vacuolar amino acid compartmentalization in S. cerevisiae cells, especially under conditions of nitrogen starvation. PMID:20118605

Chahomchuen, Thippayarat; Hondo, Kana; Ohsaki, Mariko; Sekito, Takayuki; Kakinuma, Yoshimi

2009-12-01

411

The RFC2 gene encoding a subunit of replication factor C of Saccharomyces cerevisiae.  

PubMed Central

Replication Factor C (RF-C) of Saccharomyces cerevisiae is a complex that consists of several different polypeptides ranging from 120- to 37 kDa (Yoder and Burgers, 1991; Fien and Stillman, 1992), similar to human RF-C. We have isolated a gene, RFC2, that appears to be a component of the yeast RF-C. The RFC2 gene is located on chromosome X of S. cerevisiae and is essential for cell growth. Disruption of the RFC2 gene led to a dumbbell-shaped terminal morphology, common to mutants having a defect in chromosomal DNA replication. The steady-state levels of RFC2 mRNA fluctuated less during the cell cycle than other genes involved in DNA replication. Nucleotide sequence of the gene revealed an open reading frame corresponding to a polypeptide with a calculated Mr of 39,716 and a high degree of amino acid sequence homology to the 37-kDa subunit of human RF-C. Polyclonal antibodies against bacterially expressed Rfc2 protein specifically reduced RF-C activity in the RF-C-dependent reaction catalyzed by yeast DNA polymerase III. Furthermore, the Rfc2 protein was copurified with RF-C activity throughout RF-C purification. These results strongly suggest that the RFC2 gene product is a component of yeast RF-C. The bacterially expressed Rfc2 protein preferentially bound to primed single-strand DNA and weakly to ATP. Images PMID:8202350

Noskov, V; Maki, S; Kawasaki, Y; Leem, S H; Ono, B; Araki, H; Pavlov, Y; Sugino, A

1994-01-01

412

Reconstruction and Evaluation of the Synthetic Bacterial MEP Pathway in Saccharomyces cerevisiae  

PubMed Central

Isoprenoids, which are a large group of natural and chemical compounds with a variety of applications as e.g. fragrances, pharmaceuticals and potential biofuels, are produced via two different metabolic pathways, the mevalonate (MVA) pathway and the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Here, we attempted to replace the endogenous MVA pathway in Saccharomyces cerevisiae by a synthetic bacterial MEP pathway integrated into the genome to benefit from its superior properties in terms of energy consumption and productivity at defined growth conditions. It was shown that the growth of a MVA pathway deficient S. cerevisiae strain could not be restored by the heterologous MEP pathway even when accompanied by the co-expression of genes erpA, hISCA1 and CpIscA involved in the Fe-S trafficking routes leading to maturation of IspG and IspH and E. coli genes fldA and fpr encoding flavodoxin and flavodoxin reductase believed to be responsible for electron transfer to IspG and IspH. PMID:23285068

Partow, Siavash; Siewers, Verena; Daviet, Laurent; Schalk, Michel; Nielsen, Jens

2012-01-01

413

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

PubMed Central

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 metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10–30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types. PMID:22984600

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

2012-01-01

414

Purification and partial characterization of an aldo-keto reductase from Saccharomyces cerevisiae.  

PubMed Central

A cytosolic aldo-keto reductase was purified from Saccharomyces cerevisiae ATCC 26602 to homogeneity by affinity chromatography, chromatofocusing, and hydroxylapatite chromatography. The relative molecular weights of the aldo-keto reductase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size exclusion chromatography were 36,800 and 35,000, respectively, indicating that the enzyme is monomeric. Amino acid composition and N-terminal sequence analysis revealed that the enzyme is closely related to the aldose reductases of xylose-fermenting yeasts and mammalian tissues. The enzyme was apparently immunologically unrelated to the aldose reductases of other xylose-fermenting yeasts. The aldo-keto reductase is NADPH specific and catalyzes the reduction of a variety of aldehydes. The best substrate for the enzyme is the aromatic aldehyde p-nitrobenzaldehyde (Km = 46 microM; kcat/Km = 52,100 s-1 M-1), whereas among the aldoses, DL-glyceraldehyde was the preferred substrate (Km = 1.44 mM; kcat/Km = 1,790 s-1 M-1). The enzyme failed to catalyze the reduction of menadione and p-benzoquinone, substrates for carbonyl reductase. The enzyme was inhibited only slightly by 2 mM sodium valproate and was activated by pyridoxal 5'-phosphate. The optimum pH of the enzyme is 5. These data indicate that the S. cerevisiae aldo-keto reductase is a monomeric NADPH-specific reductase with strong similarities to the aldose reductases. PMID:7747971

Kuhn, A; van Zyl, C; van Tonder, A; Prior, B A

1995-01-01

415

Transcriptional regulation of ribosomal proteins during a nutritional upshift in Saccharomyces cerevisiae.  

PubMed Central

The relative rates of synthesis of Saccharomyces cerevisiae ribosomal proteins increase coordinately during a nutritional upshift. We constructed a gene fusion which contained 528 base pairs of sequence upstream from and including the TATA box of ribosomal protein gene rp55-1 (S16A-1) fused to a CYC1-lacZ fusion. This fusion was integrated in single copy at the rp55-1 locus in the yeast genome. During a nutritional upshift, in which glucose was added to cells growing in an ethanol-based medium, we found that the increase in the relative rate of synthesis of the beta-galactosidase protein product followed the same kinetics as the change in relative rates of synthesis of several ribosomal proteins measured in the same experiment. This demonstrates that the nontranscribed sequences upstream from the rp55-1 gene, which are present in the fusion, are sufficient to mediate the change in rates of synthesis characteristic of ribosomal proteins under these conditions. The results also suggest that a change in transcription rates is mainly responsible for the increase in relative rates of synthesis of ribosomal proteins during a nutritional upshift in S. cerevisiae. Images PMID:3023933

Donovan, D M; Pearson, N J

1986-01-01

416

Direct Conversion of Xylan to Ethanol by Recombinant Saccharomyces cerevisiae Strains Displaying an Engineered Minihemicellulosome  

PubMed Central

Arabinoxylan is a heteropolymeric chain of a ?-1,4-linked xylose backbone substituted with arabinose residues, representing a principal component of plant cell walls. Here we developed recombinant Saccharomyces cerevisiae strains as whole-cell biocatalysts capable of combining hemicellulase production, xylan hydrolysis, and hydrolysate fermentation into a single step. These strains displayed a series of uni-, bi-, and trifunctional minihemicellulosomes that consisted of a miniscaffoldin (CipA3/CipA1) and up to three chimeric enzymes. The miniscaffoldin derived from Clostridium thermocellum contained one or three cohesin modules and was tethered to the cell surface through the S. cerevisiae a-agglutinin adhesion receptor. Up to three types of hemicellulases, an endoxylanase (XynII), an arabinofuranosidase (AbfB), and a ?-xylosidase (XlnD), each bearing a C-terminal dockerin, were assembled onto the miniscaffoldin by high-affinity cohesin-dockerin interactions. Compared to uni- and bifunctional minihemicellulosomes, the resulting quaternary trifunctional complexes exhibited an enhanced rate of hydrolysis of arabinoxylan. Furthermore, with an integrated d-xylose-utilizing pathway, the recombinant yeast displaying the bifunctional minihemicellulosome CipA3-XynII-XlnD could simultaneously hydrolyze and ferment birchwood xylan to ethanol with a yield of 0.31 g per g of sugar consumed. PMID:22447594

Sun, Jie; Wen, Fei; Si, Tong; Xu, Jian-He

2012-01-01

417

Saccharomyces cerevisiae gene expression changes during rotating wall vessel suspension culture  

NASA Technical Reports Server (NTRS)

This study utilizes Saccharomyces cerevisiae to study genetic responses to suspension culture. The suspension culture system used in this study is the high-aspect-ratio vessel, one type of the rotating wall vessel, that provides a high rate of gas exchange necessary for rapidly dividing cells. Cells were grown in the high-aspect-ratio vessel, and DNA microarray and metabolic analyses were used to determine the resulting changes in yeast gene expression. A significant number of genes were found to be up- or downregulated by at least twofold as a result of rotational growth. By using Gibbs promoter alignment, clusters of genes were examined for promoter elements mediating these genetic changes. Candidate binding motifs similar to the Rap1p binding site and the stress-responsive element were identified in the promoter regions of differentially regulated genes. This study shows that, as in higher order organisms, S. cerevisiae changes gene expression in response to rotational culture and also provides clues for investigations into the signaling pathways involved in gravitational response.

Johanson, Kelly; Allen, Patricia L.; Lewis, Fawn; Cubano, Luis A.; Hyman, Linda E.; Hammond, Timothy G.

2002-01-01

418

A genome-wide screen in Saccharomyces cerevisiae Reveals Pathways affected By Arsenic Toxicity  

PubMed Central

We have used Saccharomyces cerevisiae to identify toxicologically important proteins and pathways involved in arsenic-induced toxicity and carcinogenicity in humans. We performed a systemic screen of the complete set of 4,733 haploid S. cerevisiae single gene deletion mutants to identify those that have decreased or increased growth, relative to wild-type, after exposure to sodium arsenite (NaAsO2). IC50 values for all mutants were determined to further validate our results. Ultimately we identified 248 mutants sensitive to arsenite and 5 mutants resistant to arsenite exposure. We analyzed the proteins corresponding to arsenite-sensitive mutants and determined that they belonged to functional categories that include protein binding, phosphate metabolism, vacuolar/lysosomal transport, protein targeting, sorting, and translocation, cell growth/morphogenesis, cell polarity and filament formation. Furthermore, these data were mapped onto a protein interactome to identify arsenite toxicity-modulating networks. These networks are associated with the cytoskeleton, ubiquitination, histone acetylation and the MAPK signaling pathway. Our studies have potential implications for understanding toxicity and carcinogenesis in arsenic-induced human conditions, such as cancer and aging. PMID:19631266

Zhou, Xue; Arita, Adriana; Ellen, Thomas P.; Liu, Xin; Bai, Jingxiang; Rooney, John P.; Kurtz, Adrienne D.; Klein, Catherine B.; Dai, Wei; Begley, Thomas J.; Costa, Max

2009-01-01

419

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

PubMed

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

420

Mlh2 Is an Accessory Factor for DNA Mismatch Repair in Saccharomyces cerevisiae  

PubMed Central

In Saccharomyces cerevisiae, the essential mismatch repair (MMR) endonuclease Mlh1-Pms1 forms foci promoted by Msh2-Msh6 or Msh2-Msh3 in response to mispaired bases. Here we analyzed the Mlh1-Mlh2 complex, whose role in MMR has been unclear. Mlh1-Mlh2 formed foci that often colocalized with and had a longer lifetime than Mlh1-Pms1 foci. Mlh1-Mlh2 foci were similar to Mlh1-Pms1 foci: they required mispair recognition by Msh2-Msh6, increased in response to increased mispairs or downstream defects in MMR, and formed after induction of DNA damage by phleomycin but not double-stranded breaks by I-SceI. Mlh1-Mlh2 could be recruited to mispair-containing DNA in vitro by either Msh2-Msh6 or Msh2-Msh3. Deletion of MLH2 caused a synergistic increase in mutation rate in combination with deletion of MSH6 or reduced expression of Pms1. Phylogenetic analysis demonstrated that the S. cerevisiae Mlh2 protein and the mammalian PMS1 protein are homologs. These results support a hypothesis that Mlh1-Mlh2 is a non-essential accessory factor that acts to enhance the activity of Mlh1-Pms1. PMID:24811092

Srivatsan, Anjana; Bowen, Nikki; Gries, Kerstin; Desai, Arshad; Putnam, Christopher D.; Kolodner, Richard D.

2014-01-01

421

Effect of limited homology on gene conversion in a Saccharomyces cerevisiae plasmid recombination system  

SciTech Connect

Plasmids containing heteroallelic copies of the Saccharomyces cerevisiae HIS3 gene undergo intramolecular gene conservation in mitotically dividing S. cerevisiae cels. The authors used this plasmid system to determine the minimum amount of homology required for gene conversion, to examine how conversion tract lengths are affected by limited homology, and to analyze the role of flanking DNA sequences on the pattern of exchange. Plasmids with homologous sequences greater than 2 kilobases have mitotic exchange rates as high as 2 x 10/sup -3/ event soper cell per generation. As the homology is reduced, the exchange rate decreases dramatically. A plasmid with 26 base pairs (bp) of homology undergones gene conversion at a rate of approximately 1 x 10/sup -10/ events per cell per generation. These studies have also shown that an 8-bp insertion mutation 13 bp from a border between homologous and nonhomologous sequences undergoes conversion, but that a similar 8-bp insertion 5 bp from a border does not. Examination of independent conversion events which occurred in plasmids with heteroallelic copies of the HIS3 gene shows that markers within 280 bp of a border between homologous and nonhomologous sequences undergo conversion less frequently than the same markers within a more extensive homologous sequence. Thus, proximity to a border between homologous and nonhomologous sequences shortens the conversion tract length.

Ahn, B.Y.; Dornfeld, K.J.; Fagrelius, T.J.; Livingston, D.M.

1988-06-01

422

Structure of the Saccharomyces cerevisiae Cet1-Ceg1 mRNA capping apparatus  

PubMed Central

SUMMARY The 5’ guanine-N7 cap is the first co-transcriptional modification of messenger RNA. In Saccharomyces cerevisiae, the first two steps in capping are catalyzed by the RNA triphosphatase Cet1 and RNA guanylyltransferase Ceg1 which form a complex that is directly recruited to phosphorylated RNA polymerase II (RNAP IIo), primarily via contacts between RNAP IIo and Ceg1. A 3.0 Å crystal structure of Cet1-Ceg1 revealed a 176 kDa heterotetrameric complex composed of one Cet1 homodimer that associates with two Ceg1 molecules via interactions between the Ceg1 OB domain and an extended Cet1 WAQKW amino acid motif. The WAQKW motif is followed by a flexible linker that would allow Ceg1 to achieve conformational changes required for capping while maintaining interactions with both Cet1 and RNAP IIo. The impact of mutations as assessed through genetic analysis in S. cerevisiae are consonant with contacts observed in the Cet1-Ceg1 structure. PMID:20159466

Gu, Meigang; Rajashankar, Kanagalaghatta R.; Lima, Christopher D.

2010-01-01

423

Multi-Capillary Column-Ion Mobility Spectrometry of Volatile Metabolites Emitted by Saccharomyces Cerevisiae  

PubMed Central

Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption–gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism, fast and non-invasive MCC-IMS analyses provide valuable data for process control. PMID:25197771

Halbfeld, Christoph; Ebert, Birgitta E.; Blank, Lars M.

2014-01-01

424

Accumulation of phosphate and polyphosphate by Cryptococcus humicola and Saccharomyces cerevisiae in the absence of nitrogen.  

PubMed

The search for new phosphate-accumulating microorganisms is of interest in connection with the problem of excess phosphate in environment. The ability of some yeast species belonging to ascomycetes and basidiomycetes for phosphate (P (i) ) accumulation in nitrogen-deficient medium was studied. The ascomycetous Saccharomyces cerevisiae and Kuraishia capsulata and basidiomycetous Cryptococcus humicola, Cryptococcus curvatus, and Pseudozyma fusiformata were the best in P (i) removal. The cells of Cryptococcus humicola and S. cerevisiae took up 40% P (i) from the media containing P (i) and glucose (5 and 30 mM, respectively), and up to 80% upon addition of 5 mM MgSO(4) (.) The cells accumulated P (i) mostly in the form of polyphosphate (PolyP). In the presence of Mg(2+) , the content of PolyP with longer average chain length increased in both yeasts; they both had numerous inclusions fluorescing in the yellow region of the spectrum, typical of DAPI-PolyP complexes. Among the yeast species tested, Cryptococcus humicola is a new promising model organisms to study phosphorus removal from the media and biomineralization in microbial cells. PMID:22591314

Breus, Natalia A; Ryazanova, Lubov P; Dmitriev, Vladimir V; Kulakovskaya, Tatiana V; Kulaev, Igor S

2012-09-01

425

Improvement of oxidative stress tolerance in Saccharomyces cerevisiae through global transcription machinery engineering.  

PubMed

Excessive oxidative stress poses significant damage to yeast cells during fermentation process, and finally affects fermentation efficiency and the quality of products. In this paper, global transcription machinery engineering was employed to elicit Saccharomyces cerevisiae phenotypes of higher tolerance against oxidative stress caused by H2O2. Two strains from two plasmid-based mutagenesis libraries (Spt15 and Taf25), which exhibited significant increases in oxidative stress tolerance, were successfully isolated. At moderate H2O2 shock (?3.5 mM), a positive correlation was found between the outperformance in cell growth of the oxidation-tolerate strains and H2O2 concentration. Several mutations were observed in the native transcription factors, which resulted in a different transcriptional profile compared with the control. Catalase and superoxide dismutase activities of the two mutants increased under H2O2 stress conditions. Fermentation experiments revealed that the mutant strain taf25-3 has a shorter lag phase compared to the control one, indicating that taf25-3 had improved adaptation ability to H2O2-induced oxidative stress and higher fermentation efficiency. Our study demonstrated that several amino acid substitutions in general transcription factors (Spt15 and Taf25) could modify the cellular oxidation defense systems and improve the anti-oxidation ability of S. cerevisiae. It could make the industrial ethanol fermentation more efficient and cost-effective by using the strain of higher stress tolerance. PMID:24633583

Zhao, Hongwei; Li, Jingyuan; Han, Beizhong; Li, Xuan; Chen, Jingyu

2014-05-01

426

A comprehensive analysis of translational missense errors in the yeast Saccharomyces cerevisiae  

PubMed Central

The process of protein synthesis must be sufficiently rapid and sufficiently accurate to support continued cellular growth. Failure in speed or accuracy can have dire consequences, including disease in humans. Most estimates of the accuracy come from studies of bacterial systems, principally Escherichia coli, and have involved incomplete analysis of possible errors. We recently used a highly quantitative system to measure the frequency of all types of misreading errors by a single tRNA in E. coli. That study found a wide variation in error frequencies among codons; a major factor causing that variation is competition between the correct (cognate) and incorrect (near-cognate) aminoacyl-tRNAs for the mutant codon. Here we extend that analysis to measure the frequency of missense errors by two tRNAs in a eukaryote, the yeast Saccharomyces cerevisiae. The data show that in yeast errors vary by codon from a low of 4 × 10?5 to a high of 6.9 × 10?4 per codon and that error frequency is in general about threefold lower than in E. coli, which may suggest that yeast has additional mechanisms that reduce missense errors. Error rate again is strongly influenced by tRNA competition. Surprisingly, missense errors involving wobble position mispairing were much less frequent in S. cerevisiae than in E. coli. Furthermore, the error-inducing aminoglycoside antibiotic, paromomycin, which stimulates errors on all error-prone codons in E. coli, has a more codon-specific effect in yeast. PMID:20651030

Kramer, Emily B.; Vallabhaneni, Haritha; Mayer, Lauren M.; Farabaugh, Philip J.

2010-01-01

427

Construction of Novel Saccharomyces cerevisiae Strains for Bioethanol Active Dry Yeast (ADY) Production  

PubMed Central

The application of active dry yeast (ADY) in bioethanol production simplifies operation processes and reduces the risk of bacterial contamination. In the present study, we constructed a novel ADY strain with improved stress tolerance and ethanol fermentation performances under stressful conditions. The industrial Saccharomyces cerevisiae strain ZTW1 showed excellent properties and thus subjected to a modified whole-genome shuffling (WGS) process to improve its ethanol titer, proliferation capability, and multiple stress tolerance for ADY production. The best-performing mutant, Z3-86, was obtained after three rounds of WGS, producing 4.4% more ethanol and retaining 2.15-fold higher viability than ZTW1 after drying. Proteomics and physiological analyses indicated that the altered expression patterns of genes involved in protein metabolism, plasma membrane composition, trehalose metabolism, and oxidative responses contribute to the trait improvement of Z3-86. This work not only successfully developed a novel S. cerevisiae mutant for application in commercial bioethanol production, but also enriched the current understanding of how WGS improves the complex traits of microbes. PMID:24376860

Gao, Kehui; Liu, Zewei; Zhang, Xing; Li, Ou; Sun, Jianguo; Zhang, Xiaoyang; Du, Fengguang; Sun, Peiyong; Qu, Aimin; Wu, Xuechang

2013-01-01

428

Effects of hydroxyurea on immobilized and suspended yeast fermentation rates and cell cycle operation. [Saccharomyces cerevisiae  

SciTech Connect

Hydroxyurea, an inhibitor of DNA synthesis in Saccharomyces cerevisiae, has been applied in order to restrict growth of immobilized cells. For comparison, the influence of hydroxyurea on suspended S. cerevisiae has also been investigated. Recovery from DNA synthesis inhibition, indicated by measurements of cell growth rate, DNA content, and light scatter properties, occurred faster in immobilized cells than in the suspended yeast. Morphogenesis in both populations was arrested by hydroxyurea, and there was an accumulation of single immobilized and suspended cells with large buds. Synthesis of protein and RNA was not adversely affected in either cell type. The specific rate of ethanol production by immobilized cells increased by an average of 24%, while, for the suspended cells, specific ethanol productivity was up to three times higher. Glucose consumption rates for both cell types also increased under the influence of hydroxyurea. Immobilized cell ethanol yields were reduced by ca. 16% in the presence of hydroxyurea; suspended cell yields were lower by an average of 50%. Total polysaccharide content was reduced by 65% for suspended cells and increased 30% for immobilized cells after hydroxyurea treatment. The data evidence disturbance of the yeast cell cycle due to immobilization.

Doran, P.M.; Bailey, J.E.

1986-01-01

429

The protein kinase Sch9 is a key regulator of sphingolipid metabolism in Saccharomyces cerevisiae  

PubMed Central

The Saccharomyces cerevisiae protein kinase Sch9 is an in vitro and in vivo effector of sphingolipid signaling. This study examines the link between Sch9 and sphingolipid metabolism in S. cerevisiae in vivo based on the observation that the sch9? mutant displays altered sensitivity to different inhibitors of sphingolipid metabolism, namely myriocin and aureobasidin A. Sphingolipid profiling indicates that sch9? cells have increased levels of long-chain bases and long-chain base-1 phosphates, decreased levels of several species of (phyto)ceramides, and altered ratios of complex sphingolipids. We show that the target of rapamycin complex 1–Sch9 signaling pathway functions to repress the expression of the ceramidase genes YDC1 and YPC1, thereby revealing, for the first time in yeast, a nutrient-dependent transcriptional mechanism involved in the regulation of sphingolipid metabolism. In addition, we establish that Sch9 affects the activity of the inositol phosphosphingolipid phospholipase C, Isc1, which is required for ceramide production by hydrolysis of complex sphingolipids. Given that sphingolipid metabolites play a crucial role in the regulation of stress tolerance and longevity of yeast cells, our data provide a model in which Sch9 regulates the latter phenotypes by acting not only as an effector but also as a regulator of sphingolipid metabolism. PMID:24196832

Swinnen, Erwin; Wilms, Tobias; Idkowiak-Baldys, Jolanta; Smets, Bart; De Snijder, Pepijn; Accardo, Sabina; Ghillebert, Ruben; Thevissen, Karin; Cammue, Bruno; De Vos, Dirk; Bielawski, Jacek; Hannun, Yusuf A.; Winderickx, Joris

2014-01-01

430

Identification and assays of polyamine transport systems in Escherichia coli and Saccharomyces cerevisiae.  

PubMed

Polyamine content in cells is regulated by biosynthesis, degradation, and transport. With regard to transport, uptake and excretion proteins exist in Escherichia coli and Saccharomyces cerevisiae. In E. coli, the uptake systems comprise a spermidine-preferential uptake system consisting of the PotA, B, C, and D proteins, and a putrescine-specific uptake system consisting of the PotF, G, H, and I proteins. Two other proteins, PotE and CadB, each containing 12 transmembrane segments, function as antiporters (putrescine-ornithine and cadaverine-lysine) and are important for cell growth at acidic pH. MdtJI was identified as a spermidine excretion system. When putrescine was used as energy source, PuuP functioned as a putrescine transporter. In S. cerevisiae, DUR3 and SAM3, containing 16 or 12 transmembrane segments, are the major polyamine uptake proteins, whereas TPO1 and TPO5, containing 12 transmembrane segments, are the major polyamine excretion proteins, and UGA4 is a putrescine transporter on the vacuolar membrane. The activities of DUR3 and TPO1 are regulated by phosphorylation of serine/threonine residues. The identification and assay procedures of these transporters are described in this chapter. PMID:21318881

Kashiwagi, Keiko; Igarashi, Kazuei

2011-01-01

431

Primers-4-Yeast: a comprehensive web tool for planning primers for Saccharomyces cerevisiae.  

PubMed

The budding yeast Saccharomyces cerevisiae is a key model organism of functional genomics, due to its ease and speed of genetic manipulations. In fact, in this yeast, the requirement for homologous sequences for recombination purposes is so small that 40 base pairs (bp) are sufficient. Hence, an enormous variety of genetic manipulations can be performed by simply planning primers with the correct homology, using a defined set of transformation plasmids. Although designing primers for yeast transformations and for the verification of their correct insertion is a common task in all yeast laboratories, primer planning is usually done manually and a tool that would enable easy, automated primer planning for the yeast research community is still lacking. Here we introduce Primers-4-Yeast, a web tool that allows primers to be designed in batches for S. cerevisiae gene-targeting transformations, and for the validation of correct insertions. This novel tool enables fast, automated, accurate primer planning for large sets of genes, introduces consistency in primer planning and is therefore suggested to serve as a standard in yeast research. Primers-4-Yeast is available at: http://www.weizmann.ac.il/Primers-4-Yeast PMID:24408512

Yofe, Ido; Schuldiner, Maya

2014-02-01

432

A Single Heterochromatin Boundary Element Imposes Position-Independent Antisilencing Activity in Saccharomyces cerevisiae Minichromosomes  

PubMed Central

Chromatin boundary elements serve as cis-acting regulatory DNA signals required to protect genes from the effects of the neighboring heterochromatin. In the yeast genome, boundary elements act by establishing barriers for heterochromatin spreading and are sufficient to protect a reporter gene from transcriptional silencing when inserted between the silencer and the reporter gene. Here we dissected functional topography of silencers and boundary elements within circular minichromosomes in Saccharomyces cerevisiae. We found that both HML-E and HML-I silencers can efficiently repress the URA3 reporter on a multi-copy yeast minichromosome and we further showed that two distinct heterochromatin boundary elements STAR and TEF2-UASrpg are able to limit the heterochromatin spreading in circular minichromosomes. In surprising contrast to what had been observed in the yeast genome, we found that in minichromosomes the heterochromatin boundary elements inhibit silencing of the reporter gene even when just one boundary element is positioned at the distal end of the URA3 reporter or upstream of the silencer elements. Thus the STAR and TEF2-UASrpg boundary elements inhibit chromatin silencing through an antisilencing activity independently of their position or orientation in S. cerevisiae minichromosomes rather than by creating a position-specific barrier as seen in the genome. We propose that the circular DNA topology facilitates interactions between the boundary and silencing elements in the minichromosomes. PMID:21949764

Chakraborty, Sangita A.; Simpson, Robert T.; Grigoryev, Sergei A.

2011-01-01

433

Production of fructanase by a wild strain of Saccharomyces cerevisiae on tequila agave fructan.  

PubMed

A new wild strain of Saccharomyces cerevisiae (CF3) isolated from tequila must was evaluated for production of fructanase on Agave tequilana Weber fructan (FT). Fructanase activity (F) was assessed by a 3(3) factorial design (substrate, temperature and pH). High enzymatic activity (31.1 U/ml) was found at 30 °C, pH 5, using FT (10 g/l) as substrate. The effect of initial substrate concentration on F (FT0, 5.7-66 g/l) was studied and it was found that F was highest (44.8 U/ml) at FT0 25 g/l. A 2(2) factorial experimental design with five central points was utilized to study the effect of stirring and aeration on fructanase activity; stirring exhibited a stronger effect on F. The ratio fructanase to invertase (F/S) was 0.57, which confirms that the enzymes are fructanase. Crude fructanase reached high substrate hydrolysis (48 wt%) in 10 h. It is shown that S. cerevisiae CF3 was able to produce large amounts of fructanase by growing it on fructan from A. tequilana. PMID:25432071

Corona-González, R I; Pelayo-Ortiz, C; Jacques, G; Guatemala, G; Arriola, E; Arias, J A; Toriz, G

2015-01-01

434

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

PubMed

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

2015-02-01

435

Metabolic Flux Analysis during the Exponential Growth Phase of Saccharomyces cerevisiae in Wine Fermentations  

PubMed Central

As a consequence of the increase in global average temperature, grapes with the adequate phenolic and aromatic maturity tend to be overripe by the time of harvest, resulting in increased sugar concentrations and imbalanced C/N ratios in fermenting musts. This fact sets obvious additional hurdles in the challenge of obtaining wines with reduced alcohols levels, a new trend in consumer demands. It would therefore be interesting to understand Saccharomyces cerevisiae physiology during the fermentation of must with these altered characteristics. The present study aims to determine the distribution of metabolic fluxes during the yeast exponential growth phase, when both carbon and nitrogen sources are in excess, using continuous cultures. Two different sugar concentrations were studied under two different winemaking temperature conditions. Although consumption and production rates for key metabolites were severely affected by the different experimental conditions studied, the general distribution of fluxes in central carbon metabolism was basically conserved in all cases. It was also observed that temperature and sugar concentration exerted a higher effect on the pentose phosphate pathway and glycerol formation than on glycolysis and ethanol production. Additionally, nitrogen uptake, both quantitatively and qualitatively, was strongly influenced by environmental conditions. This work provides the most complete stoichiometric model used for Metabolic Flux Analysis of S. cerevisiae in wine fermentations employed so far, including the synthesis and release of relevant aroma compounds and could be used in the design of optimal nitrogen supplementation of wine fermentations. PMID:23967264

Quirós, Manuel; Martínez-Moreno, Rubén; Albiol, Joan; Morales, Pilar; Vázquez-Lima, Felícitas; Barreiro-Vázquez, Antonio; Ferrer, Pau; Gonzalez, Ramon

2013-01-01

436