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1

A structural analysis of the AAA+ domains in Saccharomyces cerevisiae cytoplasmic dynein  

PubMed Central

Dyneins are large protein complexes that act as microtubule based molecular motors. The dynein heavy chain contains a motor domain which is a member of the AAA+ protein family (ATPases Associated with diverse cellular Activities). Proteins of the AAA+ family show a diverse range of functionalities, but share a related core AAA+ domain, which often assembles into hexameric rings. Dynein is unusual because it has all six AAA+ domains linked together, in one long polypeptide. The dynein motor domain generates movement by coupling ATP driven conformational changes in the AAA+ ring to the swing of a motile element called the linker. Dynein binds to its microtubule track via a long antiparallel coiled-coil stalk that emanates from the AAA+ ring. Recently the first high resolution structures of the dynein motor domain were published. Here we provide a detailed structural analysis of the six AAA+ domains using our Saccharomycescerevisiae crystal structure. We describe how structural similarities in the dynein AAA+ domains suggest they share a common evolutionary origin. We analyse how the different AAA+ domains have diverged from each other. We discuss how this is related to the function of dynein as a motor protein and how the AAA+ domains of dynein compare to those of other AAA+ proteins.

Gleave, Emma S.; Schmidt, Helgo; Carter, Andrew P.

2014-01-01

2

Mannitol Uptake by Saccharomyces Cerevisiae.  

National Technical Information Service (NTIS)

The uptake of mannitol, a nonmetabolized hexitol, by Saccharomyces cerevisiae was measured. Various parameters examined include: effects of temperature on uptake, inhibition of uptake by uranyl nitrate, competition for uptake by glucose, counterflow of ma...

E. Spoerl W. A. Maxwell

1970-01-01

3

Epigenetics in Saccharomyces cerevisiae.  

PubMed

Saccharomyces cerevisiae provides a well-studied model system for heritable silent chromatin, in which a nonhistone protein complex--the SIR complex--represses genes by spreading in a sequence-independent manner, much like heterochromatin in higher eukaryotes. The ability to study mutations in histones and to screen genome-wide for mutations that impair silencing has yielded an unparalleled depth of detail about this system. Recent advances in the biochemistry and structural biology of the SIR-chromatin complex bring us much closer to a molecular understanding of how Sir3 selectively recognizes the deacetylated histone H4 tail and demethylated histone H3 core. The existence of appropriate mutants has also shown how components of the silencing machinery affect physiological processes beyond transcriptional repression. PMID:23818500

Grunstein, Michael; Gasser, Susan M

2013-07-01

4

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

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody...Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S. cerevisiae ...a) Identification. The Anti-Saccharomyces cerevisiae (S....

2010-04-01

5

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

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody...Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S. cerevisiae ...a) Identification. The Anti-Saccharomyces cerevisiae (S....

2009-04-01

6

Dichlorofluoromethane Inactivates Saccharomyces cerevisiae  

PubMed Central

Saccharomyces cerevisiae was incubated in aerosol cans containing YM broth and dichlorofluoromethane (f-21). The presence and number of viable cells were determined by inoculating (1% vol/vol) YM broth and by the plate count procedure (YM agar). Inactivation of the yeast was greater or more rapid when: (i) the thermodynamic activity (saturation value) of f-21 became greater through increasing the concentration of chemical from 0.5 to 1.5% (wt/wt) in a given volume (20, 40, or 80 ml) of broth, or by holding the concentration of chemical constant but increasing the volume of broth in the test vessel, (ii) the temperature of treatment was increased (7, 22, 37, and 47 C), (iii) samples with 1.5% (wt/wt) f-21 were agitated, (iv) young (8 h) rather than old (36 h or 10 days) cells were treated, and (v) cells were grown in YM broth without, rather than with, glucose. Adjusting the pH (6.3 to 4.0) of broth before treatment, pretreating the substrate with f-21, or distilling the chemical before use had no effect on viability of cells when treated with f-21. Yeast cells inactivated by f-21, chlorine, or heat were more resistant to disruption by sonic treatment than were viable cells.

Middleton, J. L.; Marth, E. H.; Fennema, O.

1975-01-01

7

Proteomic analysis of Saccharomyces cerevisiae  

Microsoft Academic Search

Nowadays, proteomics is recognized as one of the fastest growing tools in many areas of research. This is especially true for the study of Saccharomyces cerevisiae, as it is considered to be a model organism for eukaryotic cells. Proteomic analysis provides an insight into global protein expressions from identification to quantitation, from localization to function, and from individual to network

Trong Khoa Pham; Phillip C Wright

2007-01-01

8

Metabolic Engineering of Saccharomyces cerevisiae  

PubMed Central

Comprehensive knowledge regarding Saccharomyces cerevisiae has accumulated over time, and today S. cerevisiae serves as a widley used biotechnological production organism as well as a eukaryotic model system. The high transformation efficiency, in addition to the availability of the complete yeast genome sequence, has facilitated genetic manipulation of this microorganism, and new approaches are constantly being taken to metabolicially engineer this organism in order to suit specific needs. In this paper, strategies and concepts for metabolic engineering are discussed and several examples based upon selected studies involving S. cerevisiae are reviewed. The many different studies of metabolic engineering using this organism illustrate all the categories of this multidisciplinary field: extension of substrate range, improvements of producitivity and yield, elimination of byproduct formation, improvement of process performance, improvements of cellular properties, and extension of product range including heterologous protein production.

Ostergaard, Simon; Olsson, Lisbeth; Nielsen, Jens

2000-01-01

9

Transgenic Saccharomyces Cerevisiae and Method for Bioremediation.  

National Technical Information Service (NTIS)

An isolated and purified transgenic Saccharomyces cerevisiae yeast cell comprising a disrupted ACR3 gene and an isolated DNA sequence comprising a promoter operably linked to a nucleic acid molecule encoding yeast cadmium factor resistance protein Ycf1p, ...

B. Rosen M. Ghosh

2004-01-01

10

Nucleosome Positioning in Saccharomyces cerevisiae  

PubMed Central

Summary: The DNA of eukaryotic cells is spooled around large histone protein complexes, forming nucleosomes that make up the basis for a high-order packaging structure called chromatin. Compared to naked DNA, nucleosomal DNA is less accessible to regulatory proteins and regulatory processes. The exact positions of nucleosomes therefore influence several cellular processes, including gene expression, chromosome segregation, recombination, replication, and DNA repair. Here, we review recent technological advances enabling the genome-wide mapping of nucleosome positions in the model eukaryote Saccharomyces cerevisiae. We discuss the various parameters that determine nucleosome positioning in vivo, including cis factors like AT content, variable tandem repeats, and poly(dA:dT) tracts that function as chromatin barriers and trans factors such as chromatin remodeling complexes, transcription factors, histone-modifying enzymes, and RNA polymerases. In the last section, we review the biological role of chromatin in gene transcription, the evolution of gene regulation, and epigenetic phenomena.

Jansen, An; Verstrepen, Kevin J.

2011-01-01

11

Mannitol Uptake by Saccharomyces cerevisiae  

PubMed Central

The uptake of mannitol, a nonmetabolized hexitol, by Saccharomyces cerevisiae was measured. Various characteristics examined include: effects of temperature on uptake, inhibition of uptake by uranyl nitrate, competition for uptake by glucose, counterflow of mannitol by glucose, and the affinity of mannitol for a carrier system as measured by a Michaelis constant. That energy is required for uptake was shown by a decreased uptake in the presence of energy inhibitors, by an increased uptake upon addition of energy sources, and by the absence of uptake under anaerobic conditions with no fermentable energy sources available. That mannitol is bound to some cellular constituent after it enters the cell was shown by its attachment to non-dialyzable cell fragments and by the lack of an osmotic response, both of which are consistent with a minimal efflux.

Maxwell, W. A.; Spoerl, Edward

1971-01-01

12

Postreplication repair in Saccharomyces cerevisiae  

SciTech Connect

Postreplication events in logarithmically growing excision-defective mutants of Saccharomyces cerevisiae were examined after low doses of ultraviolet light. Pulse-labeled deoxyribonucleic acid had interruptions, and when the cells were chased, the interruptions were no longer detected. Since the loss of interruptions was not associated with an exchange of pyrimidine dimers at a detection level of 10 to 20% of the induced dimers, it was concluded that postreplication repair in excision-defective mutants does not involve molecular recombination. Pyrimidine dimers were assayed by utilizing the ultraviolet-endonuclease activity in extracts of Micrococcus luteus and newly developed alkaline sucrose gradient techniques, which yielded chromosomal-size deoxyribonucleic acid after treatment of irradiated cells.

Resnick, M.A.; Boyce, J.; Cox, B.

1981-04-01

13

Monoterpenoid biosynthesis in Saccharomyces cerevisiae.  

PubMed

Plant monoterpenoids belong to a large family of plant secondary metabolites with valuable applications in cosmetics and medicine. Their usual low levels and difficult purification justify the need for alternative fermentative processes for large-scale production. Geranyl diphosphate is the universal precursor of monoterpenoids. In yeast it occurs exclusively as an intermediate of farnesyl diphosphate synthesis. In the present study we investigated the potential use of Saccharomyces cerevisiae as an alternative engineering tool. The expression of geraniol synthase of Ocimum basilicum in yeast allowed a strong and specific excretion of geraniol to the growth medium, in contrast to mutants defective in farnesyl diphosphate synthase which excreted geraniol and linalool in similar amounts. A further increase of geraniol synthesis was obtained using yeast mutants defective in farnesyl diphosphate synthase. We also showed that geraniol synthase expression affects the general ergosterol pathway, but in a manner dependent on the genetic background of the strain. PMID:17096665

Oswald, Marilyne; Fischer, Marc; Dirninger, Nicole; Karst, Francis

2007-05-01

14

Centromeric DNA from Saccharomyces uvarum is functional in Saccharomyces cerevisiae  

Microsoft Academic Search

Previous comparisons of centromeric DNA sequences in laboratory strains of Saccharomyces cerevisiae have revealed conserved sequences within 120 base pairs (bp) which appear to be essential for centromere function. We wanted to find out whether centromeric DNA in Saccharomyces strains with different degrees of DNA sequence divergence carry the same conserved sequences or not. Bam HI DNA fragments from two

Joel A. Huberman; R. David Pridmore; Daniel Jger; Ben Zonneveld; Peter Philippsen

1986-01-01

15

Ancient genes of Saccharomyces cerevisiae.  

PubMed

Amber is a plant resin mainly produced by coniferous trees that, after entrapping a variety of living beings, was subjected to a process of fossilization until it turned into yellowish, translucent stones. It is also one of the best sources of ancient DNA on which to perform studies on evolution. Here a method for the sterilization of amber that allows reliable ancient DNA extraction with no actual DNA contamination is described. Working with insects taken from amber, it was possible to amplify the ATP9, PGU1 and rRNA18S ancient genes of Saccharomyces cerevisiae corresponding to samples from the Miocene and Oligocene. After comparison of the current genes with their ancient (up to 35-40 million years) counterparts it was concluded that essential genes such as rRNA18S are highly conserved and that even normal 'house-keeping' genes, such as PGU1, are strikingly conserved along the millions of years that S. cerevisiae has evolved. PMID:15256564

Veiga-Crespo, P; Poza, M; Prieto-Alcedo, M; Villa, T G

2004-07-01

16

Effect of Immobilized Materials on Saccharomyces cerevisiae  

Microsoft Academic Search

Immobilization is the process where the movement of enzymes, cells and organelles in space is restricted. This research is aimed at investigating the effect of immobilized materials on Saccharomyces cerevisiae. The immobilized materials used are palm wood blocks, bamboo chips, sugarcane chips, maize coke, and rice husk. The substrate, when passed through the packed column, would necessarily have to diffuse

Abdulfatai Jimoh

17

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; Franois 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

18

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

19

Regulation of Biotin Transport in Saccharomyces Cerevisiae.  

National Technical Information Service (NTIS)

The metabolic control of biotin transport in Saccharomyces cerevisiae was investigated. Nonproliferating cells harvested from cultures grown in excess biotin (25 ng/ml) took up small amounts of biotin, whereas cells grown in biotin-sufficient medium (0.25...

T. O. Rogers H. C. Lichstein

1969-01-01

20

Preparation of Saccharomyces cerevisiae expression plasmids.  

PubMed

Expression plasmids for Saccharomyces cerevisiae offer a wide choice of vector copy number, promoters of varying strength and selection markers. These expression plasmids are usually shuttle vectors that can be propagated both in yeast and bacteria, making them useful in gene cloning. For heterologous production of membrane proteins, we used the green fluorescent protein (GFP) fusion technology which was previously developed in the Escherichia coli system. We designed an expression plasmid carrying an inducible GAL1 promoter, a gene encoding a membrane protein of interest and the GFP-octa-histidine sequence. Here we describe construction of multi-copy yeast expression plasmids by homologous recombination in S. cerevisiae. PMID:22454112

Drew, David; Kim, Hyun

2012-01-01

21

Saccharomyces cerevisiae Polymerase ? Functions in Mitochondria  

PubMed Central

The MtArg8 reversion assay, which measures point mutation in mtDNA, indicates that in budding yeast Saccharomyces cerevisiae, DNA polymerase ? and Rev1 proteins participate in the mitochondrial DNA mutagenesis. Supporting this evidence, both polymerase ? and Rev1p were found to be localized in the mitochondria. This is the first report demonstrating that the DNA polymerase ? and Rev1 proteins function in the mitochondria.

Zhang, Hengshan; Chatterjee, Aditi; Singh, Keshav K.

2006-01-01

22

Formation of cadaverine derivatives in Saccharomyces cerevisiae  

Microsoft Academic Search

The higher homologues of cadaverine, aminopropylcadaverine (APC) and N,N-bis(3-aminopropyl)cadaverine (3APC) were formed by a wild-type strain of Saccharomyces cerevisiae, and by two mutant strains, spe 3-1 and spe 4-1, exhibiting point mutations in the genes for spermidine synthase and spermine synthase, respectively. This, together with the incomplete inhibition of APC and 3 APC formation in the presence of inhibitors of

Dale R. Walters; Tracy Cowley

1996-01-01

23

Sporulation in the Budding Yeast Saccharomyces cerevisiae  

PubMed Central

In response to nitrogen starvation in the presence of a poor carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and package the haploid nuclei produced in meiosis into spores. The formation of spores requires an unusual cell division event in which daughter cells are formed within the cytoplasm of the mother cell. This process involves the de novo generation of two different cellular structures: novel membrane compartments within the cell cytoplasm that give rise to the spore plasma membrane and an extensive spore wall that protects the spore from environmental insults. This article summarizes what is known about the molecular mechanisms controlling spore assembly with particular attention to how constitutive cellular functions are modified to create novel behaviors during this developmental process. Key regulatory points on the sporulation pathway are also discussed as well as the possible role of sporulation in the natural ecology of S. cerevisiae.

Neiman, Aaron M.

2011-01-01

24

Assessing chronological Aging in Saccharomyces cerevisiae  

PubMed Central

Saccharomyces cerevisiae is one of the most studied model organisms for the identification of genes and mechanisms that affect aging. The chronological lifespan (CLS) assay which monitors the survival of a non-dividing population, is one of the two methods to study aging in yeast. To eliminate potential artifacts and identify genes and signaling pathways that may also affect aging in higher eukaryotes, it is important to determine CLS by multiple methods. Here, we describe these methods as well as the assays to study macromolecular damage during aging in yeast, with a focus on genomic instability.

Hu, Jia; Wei, Min; Mirisola, Mario G.; Longo, Valter D.

2014-01-01

25

PCR differentiation of Saccharomyces cerevisiae from Saccharomyces bayanus/Saccharomyces pastorianus using specific primers.  

PubMed

The aim of the present study was to design species-specific primers capable of distinguishing between Saccharomyces cerevisiae, Saccharomyces bayanus/Saccharomyces pastorianus. The 5'-specific primers were designed from the ITS-1 region (between positions 150 and 182 from the 3'-SSU end) and the 3'-specific primers were located in the LSU gene (positions 560-590 from the 5'-end of this gene). These primers were tested with different collections and wild strains of these species and the results showed that the primers were capable of distinguishing between S. cerevisiae strains and S. bayanus/S. pastorianus. Not enough sequence differences were found between S. bayanus and S. pastorianus to design specific primers for these species using this region. This method offers an effective tool for a quick differentiation of the Saccharomyces strains of the most common species involved in industrial processes. PMID:11111033

Josepa, S; Guillamon, J M; Cano, J

2000-12-15

26

Dynein achieves processive motion using both stochastic and coordinated stepping  

PubMed Central

Processivity, the ability of single molecules to move continuously along a track, is a fundamental requirement of cargo-transporting molecular motors. Here, we investigate how cytoplasmic dynein, a homodimeric, microtubule-based motor, achieves processive motion. To do this we developed a versatile method for assembling Saccharomyces cerevisiae dynein heterodimers using complementary DNA oligonucleotides covalently linked to dynein monomers labeled with different organic fluorophores. Using two-color, single-molecule microscopy and high-precision, two-dimensional tracking, we find dynein has a highly variable stepping pattern that is distinct from all other processive cytoskeletal motors, which use hand-over-hand mechanisms. Uniquely, dynein stepping is stochastic when its two motor domains are close together. However, coordination emerges as the distance between motor domains increases, implying a tension-based mechanism governs these steps. This plasticity may allow tuning of dynein for the diversity of cellular functions it performs.

Qiu, Weihong; Derr, Nathan D.; Goodman, Brian S.; Villa, Elizabeth; Wu, David; Shih, William; Reck-Peterson, Samara L.

2011-01-01

27

Characterization of the Biotin Transport System in Saccharomyces Cerevisiae.  

National Technical Information Service (NTIS)

The characteristics of the biotin transport mechanism of Saccharomyces cerevisiae were investigated in nonproliferating cells. Microbiological and radioisotope assays were employed to measure biotin uptake. The vitamin existed intracellularly in both free...

T. O. Rogers H. C. Lichstein

1969-01-01

28

Acidic Calcium Stores of Saccharomyces cerevisiae  

PubMed Central

Fungi and animals constitute sister kingdoms in the eukaryotic domain of life. The major classes of transporters, channels, sensors, and effectors that move and respond to calcium ions were already highly networked in the common ancestor of fungi and animals. Since that time, some key components of the network have been moved, altered, relocalized, lost, or duplicated in the fungal and animal lineages and at the same time some of the regulatory circuitry has been dramatically rewired. Today the calcium transport and signaling networks in fungi provide a fresh perspective on the scene that has emerged from studies of the network in animal cells. This review provides an overview of calcium signaling networks in fungi, particularly the model yeast Saccharomyces cerevisiae, with special attention to the dominant roles of acidic calcium stores in fungal cell physiology.

Cunningham, Kyle W.

2011-01-01

29

Autonomously replicating sequences in Saccharomyces cerevisiae.  

PubMed Central

A method is presented for isolating DNA segments capable of autonomous replication from Saccharomyces cerevisiae chromosomal DNA based on the differential transforming ability of autonomously replicating plasmids and nonreplicating plasmids. DNA plasmids that are capable of self-replication in yeast transform yeast spheroplasts at about 1000-fold higher frequency than nonreplicating plasmids. We have cloned from total yeast DNA a number of DNA segments that permit the pBR322 plasmid carrying the yeast LEU2 gene to replicate autonomously. These plasmid clones are characterized by their ability to transform Leu- spheroplasts to Leu+ at a high frequency and their ability to replicate autonomously. Analysis of the insert DNAs carried in some of these self-replicating plasmids divides them into two categories: those that are unique in the yeast genome and those that are repetitive. Images

Chan, C S; Tye, B K

1980-01-01

30

Killer systems of the yeast Saccharomyces cerevisiae  

SciTech Connect

The killer systems of Saccharomyces cerevisiae are an unusual class of cytoplasmic symbionts of primitive eukaryotes. The genetic material of these symbionts is double-stranded RNA. They are characterized by the linearity of the genome, its fragmentation into a major and a minor fraction, which replicate separately, and their ability to control the synthesis of secretory mycocin proteins possessing a toxic action on closely related strains. The secretion of mycocins at the same time ensures acquiring of resistance to them. Strains containing killer symbionts are toxigenic and resistant to the action of their own toxin, but strains that are free of killer double-stranded RNAs are sensitive to the action of mycocins. The killer systems of S. cerevisiae have retained features relating them to viruses and are apparently the result of evolution of infectious viruses. The occurrences of such systems among monocellular eukaryotic organisms is an example of complication of the genome by means of its assembly from virus-like components. We discuss the unusual features of replication and the expression of killer systems and their utilization in the construction of vector molecules.

Nesterova, G.F.

1989-01-01

31

Enzyme encapsulation in permeabilized Saccharomyces cerevisiae cells.  

PubMed

The Saccharomyces cerevisiae cell wall provides a semipermeable barrier that can retain intracellular proteins but still permits small molecules to pass through. When S. cerevisiae cells expressing E. coli lacZ are treated with detergent to extract the cell membrane, beta-galactosidase activity in the permeabilized cells is approximately 40% of the activity of the protein in cell extract. However, the permeabilized cells can easily be collected and reused over 15 times without appreciable loss in activity. Cell wall composition and thickness can be modified using different cell strains for enzyme expression or by mutating genes involved in cell wall biosynthesis or degradation. The Sigma1278b strain cell wall is less permeable than the walls of BY4742 and W303 cells, and deleting EXG1, which encodes a 1,3-beta-glucanase, can further reduce permeability. A short Zymolyase treatment can increase cell wall permeability without rupturing the cells. Encapsulating multiple enzymes in permeabilized cells can offer kinetic advantages over the same enzymes in solution. Regeneration of ATP from AMP by adenylate kinase and pyruvate kinase encapsulated in the same cell proceeded more rapidly than regeneration using a cell extract. Combining permeabilized cells containing adenylate kinase with permeabilized cells containing pyruvate kinase can also regenerate ATP from AMP, but the kinetics of this reaction are slower than regeneration using cell extract or permeabilized cells expressing both enzymes. PMID:15058989

Chow, Chi-Kin; Palecek, Sean P

2004-01-01

32

Proteome analysis of recombinant xylose-fermentingSaccharomyces cerevisiae  

Microsoft Academic Search

Introduction of an active xylose utilization pathway into Saccharomyces cerevisiae, which does not naturally ferment pentose sugars, is likely to have a major impact on the overall cellular metabolism as the carbon introduced to the cells will now flow through the pentose phosphate pathway. The metabolic responses in the recombinant xylose-fermenting S. cerevisiae were studied at the proteome level by

Marjo Poutanen; Heini Koivistoinen; Aristos Aristidou; Nisse Kalkkinen; Laura Ruohonen

2003-01-01

33

Involvement of an Actomyosin Contractile Ring in Saccharomyces cerevisiae Cytokinesis  

Microsoft Academic Search

In Saccharomyces cerevisiae, the mother cell and bud are connected by a narrow neck. The mecha- nism by which this neck is closed during cytokinesis has been unclear. Here we report on the role of a contrac- tile actomyosin ring in this process. Myo1p (the only type II myosin in S. cerevisiae ) forms a ring at the pre- sumptive

Erfei Bi; Paul Maddox; Daniel J. Lew; E. D. Salmon; John N. McMillan; Elaine Yeh; John R. Pringle

1998-01-01

34

The flavoproteome of the yeast Saccharomyces cerevisiae.  

PubMed

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

2014-03-01

35

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 ironsulfur 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.

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

2014-01-01

36

Mating pheromones of Saccharomyces kluyveri: pheromone interactions between Saccharomyces kluyveri and Saccharomyces cerevisiae.  

PubMed

Saccharomyces kluyveri is a heterothallic yeast with two allelic mating types denoted as a-k and alpha-k by analogy with Saccharomyces cerevisiae and from the work described here. S. kluyveri produces mating pheromones analogous to those of S. cerevisiae, but which appear to have different specificity. S. kluyveri thus differs from S. cerevisiae, Hansenula wingei, and Schizosaccharomyces pombe in that it exhibits both strong constitutive agglutination and mating pheromones. alpha-k cells produce a pheromone ("alpha-k-factor") which causes a-k cells to arrest in the G1 phase of the cell cycle and to undergo a morphological change. After a period of time dependent on the concentration of alpha-k-factor, cells exposed to the factor resume cell division. alpha-k-factor has no effect on a-k/alpha-k diploids or on alpha-k cells, but at high concentration does induce G1 arrest of S. cerevisiaea cells (a-c). a-k cells produce a pheromone ("a-k-factor") which causes alpha-k cells to exhibit a morphological change. In addition, a-k cells exhibit the Bar phenotype with respect to alpha-k-factor. Partially purified preparations of S. cerevisiae alpha-factor are more active in inducing G1 arrest of a-k cells than of a-c cells. A more purified preparation of alpha-c-factor is less active against a-k cells than a-c cells, suggesting that an additional factor (KRE, kluyveri response enhancer) may be lost during purification. Attempts to mate S. kluyveri and S. cerevisiae cells by prototroph selection and by cell-to-cell mating have been unsuccessful with all combinations of mating types. Thus, S. cerevisiae and S. kluyveri are incompatible for mating even though their pheromones exhibit some physiological cross-reaction. PMID:374360

McCullough, J; Herskowitz, I

1979-04-01

37

Piecemeal Microautophagy of Nucleus in Saccharomyces cerevisiae  

PubMed Central

Nucleus-vacuole (NV) junctions in Saccharomyces cerevisiae are formed through specific interactions between Vac8p on the vacuole membrane and Nvj1p in the nuclear envelope. Herein, we report that NV junctions in yeast promote piecemeal microautophagy of the nucleus (PMN). During PMN, teardrop-like blebs are pinched from the nucleus, released into the vacuole lumen, and degraded by soluble hydrolases. PMN occurs in rapidly dividing cells but is induced to higher levels by carbon and nitrogen starvation and is under the control of the Tor kinase nutrient-sensing pathway. Confocal and biochemical assays demonstrate that Nvj1p is degraded in a PMN-dependent manner. PMN occurs normally in apg7-? cells and is, therefore, not dependent on macroautophagy. Transmission electron microscopy reveals that portions of the granular nucleolus are often sequestered into PMN structures. These results introduce a novel mode of selective microautophagy that targets nonessential components of the yeast nucleus for degradation and recycling in the vacuole.

Roberts, Paul; Moshitch-Moshkovitz, Sharon; Kvam, Erik; O'Toole, Eileen; Winey, Mark; Goldfarb, David S.

2003-01-01

38

Uptake of trehalose by Saccharomyces cerevisiae.  

PubMed

Trehalose, a storage sugar of baker's yeast, is known not to be metabolized when added to a cell suspension in water or a growth medium and to support growth only after a lag of about 10 h. However, it was transported into cells by at least two transport systems, the uptake being active, with a pH optimum at 5.5. There was no stoicheiometry with the shift of protons into cells observed at high trehalose concentrations. Trehalose remained intact in cells and was not appreciably lost to a trehalose-free medium. The uptake systems were present directly after growth on glucose, then decayed with a half-life of about 25 min but could be reactivated by aerobic incubation with trehalose, maltose, alpha-methyl-D-glucoside, glucose or ethanol. The uptake systems thus induced were different as revealed by competition experiments. At least one of the systems for trehalose uptake showed cooperative kinetics. Comparative anaysis with other disaccharides indicated the existence in Saccharomyces cerevisiae, after induction with trehalose, of at least four systems for the uptake of alpha-methyl-D-glucoside, four systems for maltose, together with the two for trehalose, variously shared by the sugars, the total of alpha-glucoside-transporting systems being five. PMID:374680

Kotyk, A; Michaljanicov, D

1979-02-01

39

Hypervariable Noncoding Sequences in Saccharomyces cerevisiae  

PubMed Central

Compared to protein-coding sequences, the evolution of noncoding sequences and the selective constraints placed on these sequences is not well characterized. To compare the evolution of coding and noncoding sequences, we have conducted a survey for DNA polymorphism at five randomly chosen loci among a diverse collection of 81 strains of Saccharomyces cerevisiae. Average rates of both polymorphism and divergence are 40% lower at noncoding sites and 90% lower at nonsynonymous sites in comparison to synonymous sites. Although noncoding and coding sequences show substantial variability in ratios of polymorphism to divergence, two of the loci, MLS1 and PDR10, show a higher rate of polymorphism at noncoding compared to synonymous sites. The high rate of polymorphism is not accompanied by a high rate of divergence and is limited to a few small regions. These hypervariable regions include sites with three segregating bases at a single site and adjacent polymorphic sites. We show that this clustering of polymorphic sites is significantly greater than one would expect on the basis of the spacing between polymorphic fourfold degenerate sites. Although hypervariable noncoding sequences could result from selection on regulatory mutations, they could also result from transient mutational hotspots.

Fay, Justin C.; Benavides, Joseph A.

2005-01-01

40

Copper transport in the yeast Saccharomyces cerevisiae  

SciTech Connect

Biochemical processes involved in the movement of copper (Cu) into and out of the yeast Saccharomyces Cerevisiae have been investigated. Overall uptake of Cu was measured by disappearance of Cu from the reaction mixture by atomic absorption sensitive to 10/sup -10/M. The process of Cu influx is composed of a prerequisite binding and subsequent transport. The binding is non-energetic but is competitively inhibited by zinc(Zn). Transport is energetic as shown by an increased influx in the presence of added glucose. This process is prevented by 2,4-dinitrophenol(DNP). Cu influx is accompanied by an exchange for potassium(K) in a ratio of K:Cu=2:1. The process of Cu efflux involves a second type of binding site, probably of low affinity but large capacity. The presence of glucose causes the binding of extracellular Cu to these sites in a non-energy-dependent mechanism which prevents Cu efflux. Zn does not compete. DNP has no effect. The K:Cu ratio of 4:1 observed in the absence of glucose suggests a lowered net Cu uptake as a result of concomitant efflux activity. Finally, in the absence but not the presence of glucose, the pH of the extracellular solution increases. These observations are consistent with the idea that (a) yeast membrane has two Cu-binding sites, one of which participates in influx and one in efflux; (b) Cu exchanges with K during influx and with protons during efflux.

Martinez, L.D.; Connelly, J.L.

1987-05-01

41

Formation of cadaverine derivatives in Saccharomyces cerevisiae.  

PubMed

The higher homologues of cadaverine, aminopropylcadaverine (APC) and N,N-bis(3-aminopropyl)cadaverine (3APC) were formed by a wild-type strain of Saccharomyces cerevisiae, and by two mutant strains, spe 3-1 and spe 4-1, exhibiting point mutations in the genes for spermidine synthase and spermine synthase, respectively. This, together with the incomplete inhibition of APC and 3APC formation in the presence of inhibitors of S-adenosylmethionine decarboxylase and spermidine synthase, suggests that the cadaverine derivatives are formed partly by the operation of a different route. However, the yeast strains were unable to utilise [14C]aspartate and lysine to form APC and 3APC. Since the ornithine decarboxylase inhibitor alpha-difluoromethylornithine (DFMO) greatly reduced the formation of APC and 3APC, it is suggested that these compounds are formed preferentially in these yeast strains from cadaverine formed by ODC. APC and 3APC formation in the yeast strains was increased substantially following exposure to 37 degrees C for 2 h. PMID:8961564

Walters, D R; Cowley, T

1996-12-01

42

Selected non-Saccharomyces wine yeasts in controlled multistarter fermentations with Saccharomyces cerevisiae.  

PubMed

Non-Saccharomyces yeasts are metabolically active during spontaneous and inoculated must fermentations, and by producing a plethora of by-products, they can contribute to the definition of the wine aroma. Thus, use of Saccharomyces and non-Saccharomyces yeasts as mixed starter cultures for inoculation of wine fermentations is of increasing interest for quality enhancement and improved complexity of wines. We initially characterized 34 non-Saccharomyces yeasts of the genera Candida, Lachancea (Kluyveromyces), Metschnikowia and Torulaspora, and evaluated their enological potential. This confirmed that non-Saccharomyces yeasts from wine-related environments represent a rich sink of unexplored biodiversity for the winemaking industry. From these, we selected four non-Saccharomyces yeasts to combine with starter cultures of Saccharomyces cerevisiae in mixed fermentation trials. The kinetics of growth and fermentation, and the analytical profiles of the wines produced indicate that these non-Saccharomyces strains can be used with S. cerevisiae starter cultures to increase polysaccharide, glycerol and volatile compound production, to reduce volatile acidity, and to increase or reduce the total acidity of the final wines, depending on yeast species and inoculum ratio used. The overall effects of the non-Saccharomyces yeasts on fermentation and wine quality were strictly dependent on the Saccharomyces/non-Saccharomyces inoculum ratio that mimicked the differences of fermentation conditions (natural or simultaneous inoculated fermentation). PMID:21569929

Comitini, Francesca; Gobbi, Mirko; Domizio, Paola; Romani, Cristina; Lencioni, Livio; Mannazzu, Ilaria; Ciani, Maurizio

2011-08-01

43

Saccharomyces cerevisiae: a versatile eukaryotic system in virology  

PubMed Central

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

Galao, Rui P; Scheller, Nicoletta; Alves-Rodrigues, Isabel; Breinig, Tanja; Meyerhans, Andreas; Diez, Juana

2007-01-01

44

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 bakers 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.

Cyert, Martha S.; Philpott, Caroline C.

2013-01-01

45

Physiological effects of 5-hydroxymethylfurfural on Saccharomyces cerevisiae  

Microsoft Academic Search

The physiological effects of 5-hydroxymethylfurfural (HMF) on Saccharomyces cerevisiae CBS 8066 in the presence and absence of furfural were studied. Experiments were carried out by pulse addition of HMF (24?g\\/l)\\u000a as well as HMF (2?g\\/l) together with furfural (2?g\\/l) to batch cultivations of S. cerevisiae. Synthetic medium with glucose (50?g\\/l) as carbon and energy source was used. Addition of 4?g\\/l

M. J. Taherzadeh; L. Gustafsson; C. Niklasson; G. Lidn

2000-01-01

46

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Yeast Extract Hydrolysate from Saccharomyces cerevisiae...Tolerances § 180.1246 Yeast Extract Hydrolysate from Saccharomyces cerevisiae...the biochemical pesticide Yeast Extract Hydrolysate from Saccharomyces...

2013-07-01

47

Immune response to Saccharomyces cerevisiae mannan conjugate in mice.  

PubMed

Mannan, the surface polysaccharide antigen of Saccharomyces cerevisiae was partially oxidized and conjugated to a protein carrier. Prepared conjugate was immunogenic in mice and re-injection elicited significant increase of anti-S. cerevisiae specific IgG and IgM serum antibodies. There was somewhat less increase in IgM serum antibodies. Serum distribution of IgG subclasses, especially IgG(2(a+b)):IgG(1) ratio throughout the immunization demonstrated effective Th1 predominance of immune response. Newly synthesized S. cerevisiae mannan conjugate could be considered as a perspective vaccine candidate for preventive immunomodulation treatment. PMID:16102519

Paulovicov, Ema; Bystrick, Slavomr; Masrov, Jana; Machov, Eva; Mislovicov, Danica

2005-11-01

48

Overproduction of geraniol by enhanced precursor supply in Saccharomyces cerevisiae.  

PubMed

Monoterpene geraniol, a compound obtained from aromatic plants, has wide applications. In this study, geraniol was synthesized in Saccharomyces cerevisiae through the introduction of geraniol synthase. To increase geraniol production, the mevalonate pathway in S. cerevisiae was genetically manipulated to enhance the supply of geranyl diphosphate, a substrate used for the biosynthesis of geraniol. Identification and optimization of the key regulatory points in the mevalonate pathway in S. cerevisiae increased geraniol production to 36.04 mg L(-1). The results obtained revealed that the IDI1-encoded isopentenyl diphosphate isomerase is a rate-limiting enzyme in the biosynthesis of geraniol in S. cerevisiae, and overexpression of MAF1, a negative regulator in tRNA biosynthesis, is another effective method to increase geraniol production in S. cerevisiae. PMID:24161921

Liu, Jidong; Zhang, Weiping; Du, Guocheng; Chen, Jian; Zhou, Jingwen

2013-12-01

49

Mitochondria-mediated nuclear mutator phenotype in Saccharomyces cerevisiae  

Microsoft Academic Search

Using Saccharomyces cerevisiae as a model organ- ism, we analyzed the consequences of disrupting mitochondrial function on mutagenesis of the nuclear genome. We measured the frequency of canavanine-resistant colonies as a measure of nuclear mutator phenotype. Our data suggest that mitochondrial dysfunction leads to a nuclear muta- tor phenotype (i) when oxidative phosphorylation is blocked in wild-type yeast at mitochondrial

Anne Karin Rasmussen; Aditi Chatterjee; Lene Juel Rasmussen; Keshav K. Singh

2003-01-01

50

The effect of sulfite on the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

After a short period of tolerance, living cells of Saccharomyces cerevisiae were irreversibly damaged by low concentrations of sulfite. The length of the period of tolerance and the rate of the damaging effect depended on the concentration on sulfite, pH-value, temperature, the physiological state of the cells, and incubation time.

Karl-Ludwig Schimz

1980-01-01

51

Stoichiometry and compartmentation of NADH metabolism in Saccharomyces cerevisiae  

Microsoft Academic Search

In Saccharomyces cerevisiae, reduction of NAD+ to NADH occurs in dissimilatory as well as in assimilatory reactions. This review discusses mechanisms for reoxidation of NADH in this yeast, with special emphasis on the metabolic compartmentation that occurs as a consequence of the impermeability of the mitochondrial inner membrane for NADH and NAD+. At least five mechanisms of NADH reoxidation exist

Barbara M. Bakker; Karin M. Overkamp; Antonius J. A. van Maris; Peter Ktter; Marijke A. H. Luttik; Johannes P. van Dijken; Jack T. Pronk

2001-01-01

52

Origin and domestication of the wine yeast Saccharomyces cerevisiae  

Microsoft Academic Search

Recent ecological evidence points to a circulation model for Saccharomyces cerevisiae in nature which is different from that proposed at the end of the last century. The wine yeast par excellence is isolated with extreme difficulty from conventional habitats, such as vineyard soil or the surface of ripe grapes, while it is almost the only species colonising the surfaces of

Alessandro Martini

1993-01-01

53

Biolistic nuclear transformation of Saccharomyces cerevisiae and other fungi  

Microsoft Academic Search

Tungsten microprojectiles coated with nucleic acid and accelerated to velocities of approximately 500 m\\/s, can penetrate living cells and tissues with consequent expression of the introduced genes (Klein et al. 1987). Saccharomyces cerevisiae is used here as a model system to define the basic parameters governing the biolistic (biological-ballistic) delivery of DNA into cells. Among the physical factors affecting the

Daniele Armaleo; Guang-Ning Ye; Theodore M. Klein; Katherine B. Shark; John C. Sanford; Stephen Albert Johnston

1990-01-01

54

Molecular epidemiology of Saccharomyces cerevisiae in an immunocompromised host unit  

Microsoft Academic Search

Saccharomyces cerevisiae is increasingly recognized clinically, and repeated isolations from patients on a hematology unit in Turku, Finland, led to an epidemiologic investigation. Isolates were recovered from multiple body sites of 23 patients (n = 180) from 1994 to 1995 and from 29 patients (n = 45) from 1997 to 2002; these plus 2 from the hospital kitchen were identified

Karl V. Clemons; Juha H. Salonen; Jouni Issakainen; Jukka Nikoskelainen; Michael J. McCullough; Jacks J. Jorge; David A. Stevens

2010-01-01

55

Extrachromosomal inheritance of paromomycin resistance in Saccharomyces cerevisiae  

Microsoft Academic Search

In Saccharomyces cerevisiae, mutants were isolated which show high resistance to the aminoglycoside paromomycin. Amino acid incorporation of mitochondria isolated from such mutant strains proved also to be paromomycin resistant. All of them are cross-resistant to the structurally related antibiotic neomycin. Three independent methods revealed the resistance to be extrachromosomally, presumably mitochondrially inherited.

Regina Kutzleb; Rudolf J. Schweyen; Fritz Kaudewitz

1973-01-01

56

Genome-Scale Reconstruction of the Saccharomyces cerevisiae Metabolic Network  

Microsoft Academic Search

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

Jochen Forster; Iman Famili; Patrick Fu; Bernhard ; Jens Nielsen

2003-01-01

57

Saccharomyces cerevisiae Vacuole in Zinc Storage and Intracellular Zinc Distribution  

Microsoft Academic Search

Previous studies of the yeast Saccharomyces cerevisiae indicated that the vacuole is a major site of zinc storage in the cell. However, these studies did not address the absolute level of zinc that was stored in the vacuole nor did they examine the abundances of stored zinc in other compartments of the cell. In this report, we describe an analysis

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

2007-01-01

58

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

59

Identification and Characterization of Phenylpyruvate Decarboxylase Genes in Saccharomyces cerevisiae  

Microsoft Academic Search

Received 9 December 2002\\/Accepted 7 May 2003 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

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

2003-01-01

60

Synthesis of ribosomes in Saccharomyces cerevisiae.  

PubMed Central

The assembly of a eucaryotic ribosome requires the synthesis of four ribosomal ribonucleic acid (RNA) molecules and more than 75 ribosomal proteins. It utilizes all three RNA polymerases; it requires the cooperation of the nucleus and the cytoplasm, the processing of RNA, and the specific interaction of RNA and protein molecules. It is carried out efficiently and is exquisitely sensitive to the needs of the cell. Our current understanding of this process in the genetically tractable yeast Saccharomyces cerevisiae is reviewed. The ribosomal RNA genes are arranged in a tandem array of 100 to 200 copies. This tandem array has led to unique ways of carrying out a number of functions. Replication is asymmetric and does not initiate from every autonomously replicating sequence. Recombination is suppressed. Transcription of the major ribosomal RNA appears to involve coupling between adjacent transcription units, which are separated by the 5S RNA transcription unit. Genes for many ribosomal proteins have been cloned and sequenced. Few are linked; most are duplicated; most have an intron. There is extensive homology between yeast ribosomal proteins and those of other species. Most, but not all, of the ribosomal protein genes have one or two sites that are essential for their transcription and that bind a common transcription factor. This factor binds also to many other places in the genome, including the telomeres. There is coordinated transcription of the ribosomal protein genes under a variety of conditions. However, the cell seems to possess no mechanism for regulating the transcription of individual ribosomal protein genes in response either to a deficiency or an excess of a particular ribosomal protein. A deficiency causes slow growth. Any excess ribosomal protein is degraded very rapidly, with a half-life of 1 to 5 min. Unlike most types of cells, yeast cells appear not to regulate the translation of ribosomal proteins. However, in the case of ribosomal protein L32, the protein itself causes a feedback inhibition of the splicing of the transcript of its own gene. The synthesis of ribosomes involves a massive transfer of material across the nuclear envelope in both directions. Nuclear localization signals have been identified for at least three ribosomal proteins; they are similar but not identical to those identified for the simian virus 40 T antigen. There is no information about how ribosomal subunits are transported from the nucleus to the cytoplasm.(ABSTRACT TRUNCATED AT 400 WORDS)

Warner, J R

1989-01-01

61

Thermal and storage stability of Saccharomyces cerevisiae (baker's yeast) allergens.  

PubMed

The effect of storage and high temperatures on the stability of Saccharomyces cerevisiae allergens was studied by immunoblotting. Saccharomyces cerevisiae allergic serum pool and 125I- and galactosidase-labelled anti-IgE were used in the assays. Freeze-dried extracts were reconstituted with saline and with 50% glycerol and then stored at room (+20 degrees C) and refrigerator temperature (+6 degrees C) for different time periods. The stability was better in 50% glycerol at +6 degrees C than at room temperature without glycerol. However, after 1 month, two of the most important allergens of S. cerevisiae, the 48 and 32 kDa protein allergens, lost their IgE-binding capacity even in the extracts stored with 50% glycerol at +6 degrees C. The 45 kDa allergen was, on the other hand, quite stable after storage for 9 months at +6 degrees C. Although the beneficial effect of 50% glycerol was clear, storage at +6 degrees C, even with 50% glycerol should not exceed 1 month for S. cerevisiae extracts. Two commercially available S. cerevisiae extracts in solution with valid expiry dates were also analysed. They had only little allergenic potency, while a freeze-dried extract stored for 8 years showed good allergenic potency. Heating S. cerevisiae extracts resulted in precipitation, the precipitated fraction contained almost all the specific proteins as judged by electrophoresis and IgE detection. The supernatant fraction contained only a few allergens. PMID:8012857

Kortekangas-Savolainen, O; Einarsson, R

1994-03-01

62

Evolutionary engineering of Saccharomyces cerevisiae for efficient aerobic xylose consumption.  

PubMed

Industrial biotechnology aims to develop robust microbial cell factories, such as Saccharomyces cerevisiae, to produce an array of added value chemicals presently dominated by petrochemical processes. Xylose is the second most abundant monosaccharide after glucose and the most prevalent pentose sugar found in lignocelluloses. Significant research efforts have focused on the metabolic engineering of S. cerevisiae for fast and efficient xylose utilization. This study aims to metabolically engineer S. cerevisiae, such that it can consume xylose as the exclusive substrate while maximizing carbon flux to biomass production. Such a platform may then be enhanced with complementary metabolic engineering strategies that couple biomass production with high value-added chemical. Saccharomyces cerevisiae, expressing xylose reductase, xylitol dehydrogenase and xylulose kinase, from the native xylose-metabolizing yeast Pichia stipitis, was constructed, followed by a directed evolution strategy to improve xylose utilization rates. The resulting S. cerevisiae strain was capable of rapid growth and fast xylose consumption producing only biomass and negligible amount of byproducts. Transcriptional profiling of this strain was employed to further elucidate the observed physiology confirms a strongly up-regulated glyoxylate pathway enabling respiratory metabolism. The resulting strain is a desirable platform for the industrial production of biomass-related products using xylose as a sole carbon source. PMID:22487265

Scalcinati, Gionata; Otero, Jos Manuel; Van Vleet, Jennifer R H; Jeffries, Thomas W; Olsson, Lisbeth; Nielsen, Jens

2012-08-01

63

Evidence for domesticated and wild populations of Saccharomyces cerevisiae.  

PubMed

Saccharomyces cerevisiae is predominantly found in association with human activities, particularly the production of alcoholic beverages. S. paradoxus, the closest known relative of S. cerevisiae, is commonly found on exudates and bark of deciduous trees and in associated soils. This has lead to the idea that S. cerevisiae is a domesticated species, specialized for the fermentation of alcoholic beverages, and isolates of S. cerevisiae from other sources simply represent migrants from these fermentations. We have surveyed DNA sequence diversity at five loci in 81 strains of S. cerevisiae that were isolated from a variety of human and natural fermentations as well as sources unrelated to alcoholic beverage production, such as tree exudates and immunocompromised patients. Diversity within vineyard strains and within sak strains is low, consistent with their status as domesticated stocks. The oldest lineages and the majority of variation are found in strains from sources unrelated to wine production. We propose a model whereby two specialized breeds of S. cerevisiae have been created, one for the production of grape wine and one for the production of sak wine. We estimate that these two breeds have remained isolated from one another for thousands of years, consistent with the earliest archeological evidence for wine-making. We conclude that although there are clearly strains of S. cerevisiae specialized for the production of alcoholic beverages, these have been derived from natural populations unassociated with alcoholic beverage production, rather than the opposite. PMID:16103919

Fay, Justin C; Benavides, Joseph A

2005-07-01

64

Evidence for Domesticated and Wild Populations of Saccharomyces cerevisiae  

PubMed Central

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

Fay, Justin C; Benavides, Joseph A

2005-01-01

65

ANALYSIS OF CYTOPLASMIC mRNA DECAY IN SACCHAROMYCES CEREVISIAE  

PubMed Central

The yeast, Saccharomyces cerevisiae, is a model system for the study of eukaryotic mRNA degradation. In this organism, a variety of methods have been developed to measure mRNA decay rates, trap intermediates in the mRNA degradation process, and establish precursorproduct relationships. In addition, the use of mutant strains lacking specific enzymes involved in mRNA destruction, or key regulatory proteins, allows one to determine the mechanisms by which individual mRNAs are degraded. In this chapter, we discuss methods for analyzing mRNA degradation in S. cerevisiae.

Passos, Dario O.; Parker, Roy

2010-01-01

66

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.

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

2014-01-01

67

Chimeric Genomes of Natural Hybrids of Saccharomyces cerevisiae and Saccharomyces kudriavzevii?  

PubMed Central

Recently, a new type of hybrid resulting from the hybridization between Saccharomyces cerevisiae and Saccharomyces kudriavzevii was described. These strains exhibit physiological properties of potential biotechnological interest. A preliminary characterization of these hybrids showed a trend to reduce the S. kudriavzevii fraction of the hybrid genome. We characterized the genomic constitution of several wine S. cerevisiae S. kudriavzevii strains by using a combined approach based on the restriction fragment length polymorphism analysis of gene regions, comparative genome hybridizations with S. cerevisiae DNA arrays, ploidy analysis, and gene dose determination by quantitative real-time PCR. The high similarity in the genome structures of the S. cerevisiae S. kudriavzevii hybrids under study indicates that they originated from a single hybridization event. After hybridization, the hybrid genome underwent extensive chromosomal rearrangements, including chromosome losses and the generation of chimeric chromosomes by the nonreciprocal recombination between homeologous chromosomes. These nonreciprocal recombinations between homeologous chromosomes occurred in highly conserved regions, such as Ty long terminal repeats (LTRs), rRNA regions, and conserved protein-coding genes. This study supports the hypothesis that chimeric chromosomes may have been generated by a mechanism similar to the recombination-mediated chromosome loss acting during meiosis in Saccharomyces hybrids. As a result of the selective processes acting during fermentation, hybrid genomes maintained the S. cerevisiae genome but reduced the S. kudriavzevii fraction.

Belloch, Carmela; Perez-Torrado, Roberto; Gonzalez, Sara S.; Perez-Ortin, Jose E.; Garcia-Martinez, Jose; Querol, Amparo; Barrio, Eladio

2009-01-01

68

Membrane-associated phosphatidylinositol kinase from Saccharomyces cerevisiae.  

PubMed Central

Membrane-associated phosphatidylinositol kinase (ATP:phosphatidylinositol 4-phosphotransferase, EC 2.7.1.67) was partially purified 93-fold from Saccharomyces cerevisiae. Activity was dependent on magnesium ions (10 mM) and the optimum pH was 8.5. The apparent Km values for ATP and phosphatidylinositol were 0.21 mM and 71 microM, respectively. Activity was stimulated by sodium cholate and inhibited by sodium, potassium, lithium, and fluoride ions.

McKenzie, M A; Carman, G M

1983-01-01

69

MET17 and Hydrogen Sulfide Formation in Saccharomyces cerevisiae  

Microsoft Academic Search

Commercial isolates of Saccharomyces cerevisiae differ in the production of hydrogen sulfide (H2S) during fermentation, which has been attributed to variation in the ability to incorporate reduced sulfur into organic compounds. We transformed two commercial strains (UCD522 and UCD713) with a plasmid overexpressing the MET17 gene, which encodes the bifunctional O-acetylserine\\/O-acetylhomoserine sulfhydrylase (OAS\\/OAH SHLase), to test the hypothesis that the

APOSTOLOS SPIROPOULOS; LINDA F. BISSON

2000-01-01

70

Fixation of spent Saccharomyces cerevisiae biomass for lead sorption  

Microsoft Academic Search

Spent Saccharomyces cerevisiae cells from a beer fermentation process were evaluated for lead cation sorption. The crude biomass was washed with water and\\u000a acetone prior to any other treatment. Although the washed biomass showed substantial lead ion sorption it was susceptible\\u000a to microbial spoilage. Different aldehydes were tested as chemical fixation agents; however, most of them caused drastic lowering\\u000a of

R. Ashkenazy; S. Yannai; R. Rahman; E. Rabinovitz; L. Gottlieb

1999-01-01

71

A new killer toxin produced by Saccharomyces cerevisiae  

Microsoft Academic Search

A wine-making Saccharomyces cerevisiae yeast strain isolated in our laboratory produces two different killer toxins, each one encoded by one dsRNA plasmid. One toxin has the same specificity as the one produced by strain M437 described by Naumov, but the dsRNA plasmid which encodes it migrates slightly faster in poly acrylamide gel electrophoresis. The other toxin has not been previously

A. L. Extremera; I. Martin; E. Montoya

1982-01-01

72

Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan  

Microsoft Academic Search

In diverse organisms, calorie restriction slows the pace of ageing and increases maximum lifespan. In the budding yeast Saccharomyces cerevisiae, calorie restriction extends lifespan by increasing the activity of Sir2 (ref. 1), a member of the conserved sirtuin family of NAD+-dependent protein deacetylases. Included in this family are SIR-2.1, a Caenorhabditis elegans enzyme that regulates lifespan, and SIRT1, a human

Konrad T. Howitz; Kevin J. Bitterman; Haim Y. Cohen; Dudley W. Lamming; Siva Lavu; Jason G. Wood; Robert E. Zipkin; Phuong Chung; Anne Kisielewski; Li-Li Zhang; Brandy Scherer; David A. Sinclair

2003-01-01

73

Saccharomyces cerevisiae Structural Changes Induced by Pulsed Electric Field Treatment  

Microsoft Academic Search

Saccharomyces cerevisiae(ATCC 16664) inoculated into commercial heat sterilized apple juice was treated with high intensity (40 kV\\/cm) pulsed electric fields (PEF). Transmission electron microscopy (TEM) observations of PEF treatedS. cerevisiaecells provided little evidence to support the electroporation inactivation theory as the major mode of yeast inactivation. TEM micrographs of PEF treatedS. cerevisiaefrom apple juice exhibited frequent disruption of yeast cellular

Steven L. Harrison; Gustavo V. Barbosa-Cnovas; Barry G. Swanson

1997-01-01

74

Glucose Regulation of Saccharomyces cerevisiae Cell Cycle Genes  

Microsoft Academic Search

Nutrient-limited Saccharomyces cerevisiae cells rapidly resume proliferative growth when transferred into glucose medium. This is preceded by a rapid increase in CLN3, BCK2, and CDC28 mRNAs encoding cell cycle regulatory proteins that promote progress through Start. We have tested the ability of mutations in known glucose signaling pathways to block glucose induction of CLN3, BCK2, and CDC28. We find that

Laura L. Newcomb; Jasper A. Diderich; Matthew G. Slattery; Warren Heideman

2003-01-01

75

Availability of substratum enhances ethanol production in Saccharomyces cerevisiae  

Microsoft Academic Search

Novel additives that act as substratum for attachment of the yeast cells, increased ethanol production in Saccharomyces cerevisiae. The addition of 2 g rice husk, straw, wood shavings, plastic pieces or silica gel to 100ml medium enhanced ethanol production by 3040 (v\\/v). Six distillery strains showed an average enhancement of 34 from 4.1 (v\\/v) in control to 5.5 (v\\/v) on

Santosh N. Sankh; Akalpita U. Arvindekar

2004-01-01

76

Effect of Polygodial on the Mitochondrial ATPase of Saccharomyces cerevisiae  

Microsoft Academic Search

The fungicidal mechanism of a naturally occurring sesquiterpene dialdehyde, polygodial, was investigated in Saccharomyces cerevisiae. In an acidification assay, polygodial completely suppressed the glucose-induced de- crease in external pH at 3.13 mg\\/ml, the same as the fungicidal concentration. Acidification occurs primarily through the proton-pumping action of the plasma membrane ATPase, Pma1p. Surprisingly, this ATPase was not directly inhibited by polygodial.

CHRISTOPHER S. LUNDE; ISAO KUBO

2000-01-01

77

Protein Phosphatase Type 1 Regulates Ion Homeostasis in Saccharomyces cerevisiae  

Microsoft Academic Search

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

Tara Williams-Hart; Xiaolin Wu; Kelly Tatchell

78

Metabolic Engineering of Saccharomyces cerevisiae for Xylose Utilization  

Microsoft Academic Search

Metabolic engineering of Saccharomyces cerevisiae for ethanolic fermentation of xylose is summarized with emphasis on progress made during the last decade. Advances in xylose\\u000a transport, initial xylose metabolism, selection of host strains, transformation and classical breeding techniques applied\\u000a to industrial polyploid strains as well as modeling of xylose metabolism are discussed. The production and composition of\\u000a the substrates lignocellulosic

Brbel Hahn-Hgerdal; C. Fredrik Wahlbom; Mrk Grdonyi; Willem H. van Zyl; Ricardo R. Cordero Otero; L eif J. Jnsson

79

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

Microsoft Academic Search

Four thermotolerant, osmotolerant, flocculating alcohol producing cultures of Saccharomyces cerevisiae were isolated from soil samples collected from a thermal power plant in India. All the isolates grew at 44C but VS1 and VS3 were better than the other two. Maximum ethanol yields obtained from 150 g\\/l glucose were 75 and 60 g\\/l using culture VS3 at 30C and 40C, respectively.

N. Kiran Sree; M. Sridhar; K. Suresh; I. M. Banat; L. Venkateswar Rao

2000-01-01

80

Filamentous Growth of Saccharomyces cerevisiae Is Regulated by Manganese  

Microsoft Academic Search

The Candida albicans INT1 gene is a virulence factor that contributes to both adhesion and filamentous growth of the fungus. Expression of INT1 in the budding yeast Saccharomyces cerevisiae directs both adhesion and filamentous growth. Because Int1p contains two predicted divalent cation-binding motifs, we asked whether divalent cations are important for the role of Int1p in filament formation. In this

Catherine M. Asleson; John C. Asleson; Emily Malandra; Stephen Johnston; Judith Berman

2000-01-01

81

Ethanol production by Saccharomyces cerevisiae in biofilm reactors  

Microsoft Academic Search

Biofilms are natural forms of cell immobilization in which microorganisms attach to solid supports. At ISU, we have developed\\u000a plastic composite-supports (PCS) (agricultural material (soybean hulls or oat hulls), complex nutrients, and polypropylene)\\u000a which stimulate biofilm formation and which supply nutrients to the attached microorganisms. Various PCS blends were initially\\u000a evaluated in repeated-batch culture-tube fermentation with Saccharomyces cerevisiae (ATCC 24859)

A Demirci; A L Pometto III; K-L G Ho

1997-01-01

82

Purification and characterization of Put1p from Saccharomyces cerevisiae  

Microsoft Academic Search

In Saccharomyces cerevisiae, the PUT1 and PUT2 genes are required for the conversion of proline to glutamate. The PUT1 gene encodes Put1p, a proline dehydrogenase (PRODH) enzyme localized in the mitochondrion. Put1p was expressed and purified from Escherichia coli and shown to have a UVvisible absorption spectrum that is typical of a bound flavin cofactor. A Km value of 36mM

Srimevan Wanduragala; Nikhilesh Sanyal; Xinwen Liang; Donald F. Becker

2010-01-01

83

Regulation of galactokinase ( GAL1 ) enzyme accumulation in Saccharomyces cerevisiae  

Microsoft Academic Search

The regulation of GAL1 RNA and enzyme synthesis has been investigated in Saccharomyces cerevisiae. We have shown that the induction of GAL10 and GAL1 RNAs is coordinate. GAL1 RNA transcripts appear within 4.5 to 6 min and galactokinase synthesis within 6 to 9 min. Steady-state RNA levels were reached within 50 min and the steady-state rate of galactokinase enzyme synthesis

James G. Yargera; Harlyn O. Halvorson; James E. Hopper

1984-01-01

84

Identification of Genes Affecting Hydrogen Sulfide Formation in Saccharomyces cerevisiae  

Microsoft Academic Search

A screen of the Saccharomyces cerevisiae deletion strain set was performed to identify genes affecting hydrogen sulfide (H2S) production. Mutants were screened using two assays: colony color on BiGGY agar, which detects the basal level of sulfite reductase activity, and production of H2S in a synthetic juice medium using lead acetate detection of free sulfide in the headspace. A total

Angela L. Linderholm; Carrie L. Findleton; Gagandeep Kumar; Yeun Hong; Linda F. Bisson

2008-01-01

85

Kinetics of Phosphate Ions Induced Invertase Synthesis by Saccharomyces cerevisiae  

Microsoft Academic Search

Invertase (?-fructofuranosidase) is a high cost enzyme. Aim of present study was to develop an economically feasible synthetic fermentation medium with appropriate supplemented nutrients. Saccharomyces cerevisiae GCB-K5 was used for investigation. Phosphate ions in fermentation medium greatly influence the invertase secretion capacity of yeast cells. By comparing the kinetic parameters, namely product yield coefficient (Yp\\/x, Yp\\/s in Amount of enzyme

KIRAN SHAFIQ; SIKANDER ALI

86

Growth of non-Saccharomyces yeasts affects nutrient availability for Saccharomyces cerevisiae during wine fermentation.  

PubMed

Yeast produces numerous secondary metabolites during fermentation that impact final wine quality. Although it is widely recognized that growth of diverse non-Saccharomyces (NS) yeast can positively affect flavor complexity during Saccharomyces cerevisiae wine fermentation, the inability to control spontaneous or co-fermentation processes by NS yeast has restricted their use in winemaking. We selected two NS yeasts from our Uruguayan native collection to study NS-S. cerevisiae interactions during wine fermentation. The selected strains of Hanseniaspora vineae and Metschnikowia pulcherrima had different yeast assimilable nitrogen consumption profiles and had different effects on S. cerevisiae fermentation and growth kinetics. Studies in which we varied inoculum size and using either simultaneous or sequential inoculation of NS yeast and S. cerevisiae suggested that competition for nutrients had a significant effect on fermentation kinetics. Sluggish fermentations were more pronounced when S. cerevisiae was inoculated 24h after the initial stage of fermentation with a NS strain compared to co-inoculation. Monitoring strain populations using differential WL nutrient agar medium and fermentation kinetics of mixed cultures allowed for a better understanding of strain interactions and nutrient addition effects. Limitation of nutrient availability for S. cerevisiae was shown to result in stuck fermentations as well as to reduce sensory desirability of the resulting wine. Addition of diammonium phosphate (DAP) and a vitamin mix to a defined medium allowed for a comparison of nutrient competition between strains. Addition of DAP and the vitamin mix was most effective in preventing stuck fermentations. PMID:22687186

Medina, Karina; Boido, Eduardo; Dellacassa, Eduardo; Carrau, Francisco

2012-07-01

87

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

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

2009-12-01

88

Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation  

PubMed Central

Lactose is an interesting carbon source for the production of several bio-products by fermentation, primarily because it is the major component of cheese whey, the main by-product of dairy activities. However, the microorganism more widely used in industrial fermentation processes, the yeast Saccharomyces cerevisiae, does not have a lactose metabolization system. Therefore, several metabolic engineering approaches have been used to construct lactose-consuming S. cerevisiae strains, particularly involving the expression of the lactose genes of the phylogenetically related yeast Kluyveromyces lactis, but also the lactose genes from Escherichia coli and Aspergillus niger, as reviewed here. Due to the existing large amounts of whey, the production of bio-ethanol from lactose by engineered S. cerevisiae has been considered as a possible route for whey surplus. Emphasis is given in the present review on strain improvement for lactose-to-ethanol bioprocesses, namely flocculent yeast strains for continuous high-cell-density systems with enhanced ethanol productivity.

Guimaraes, Pedro MR; Oliveira, Carla

2010-01-01

89

Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation.  

PubMed

Lactose is an interesting carbon source for the production of several bio-products by fermentation, primarily because it is the major component of cheese whey, the main by-product of dairy activities. However, the microorganism more widely used in industrial fermentation processes, the yeast Saccharomyces cerevisiae, does not have a lactose metabolization system. Therefore, several metabolic engineering approaches have been used to construct lactose-consuming S. cerevisiae strains, particularly involving the expression of the lactose genes of the phylogenetically related yeast Kluyveromyces lactis, but also the lactose genes from Escherichia coli and Aspergillus niger, as reviewed here. Due to the existing large amounts of whey, the production of bio-ethanol from lactose by engineered S. cerevisiae has been considered as a possible route for whey surplus. Emphasis is given in the present review on strain improvement for lactose-to-ethanol bioprocesses, namely flocculent yeast strains for continuous high-cell-density systems with enhanced ethanol productivity. PMID:21326922

Domingues, Luclia; Guimares, Pedro M R; Oliveira, Carla

2010-01-01

90

Overproduction of threonine by Saccharomyces cerevisiae mutants resistant to hydroxynorvaline.  

PubMed Central

In this work, we isolated and characterized mutants that overproduce threonine from Saccharomyces cerevisiae. The mutants were selected for resistance to the threonine analog alpha-amino-beta-hydroxynorvalerate (hydroxynorvaline), and, of these, the ones able to excrete threonine to the medium were chosen. The mutant strains produce between 15 and 30 times more threonine than the wild type does, and, to a lesser degree, they also accumulate isoleucine. Genetic and biochemical studies have revealed that the threonine overproduction is, in all cases studied, associated with the presence in the strain of a HOM3 allele coding for a mutant aspartate kinase that is totally or partially insensitive to feedback inhibition by threonine. This enzyme seems, therefore, to be crucial in the regulation of threonine biosynthesis in S. cerevisiae. The results obtained suggest that this strategy could be efficiently applied to the isolation of threonine-overproducing strains of yeasts other than S. cerevisiae, even those used industrially.

Ramos, C; Calderon, I L

1992-01-01

91

Saccharomyces cerevisiae S288C genome annotation: a working hypothesis  

PubMed Central

The S. cerevisiae genome is the most well-characterized eukaryotic genome and one of the simplest in terms of identifying open reading frames (ORFs), yet its primary annotation has been updated continually in the decade since its initial release in 1996 (Goffeau et al., 1996). The Saccharomyces Genome Database (SGD; www.yeastgenome.org) (Hirschman et al., 2006), the community-designated repository for this reference genome, strives to ensure that the S. cerevisiae annotation is as accurate and useful as possible. At SGD, the S. cerevisiae genome sequence and annotation are treated as a working hypothesis, which must be repeatedly tested and refined. In this paper, in celebration of the tenth anniversary of the completion of the S. cerevisiae genome sequence, we discuss the ways in which the S. cerevisiae sequence and annotation have changed, consider the multiple sources of experimental and comparative data on which these changes are based, and describe our methods for evaluating, incorporating and documenting these new data.

Fisk, Dianna G.; Ball, Catherine A.; Dolinski, Kara; Engel, Stacia R.; Hong, Eurie L.; Issel-Tarver, Laurie; Schwartz, Katja; Sethuraman, Anand; Botstein, David; Cherry, J. Michael

2011-01-01

92

Ethanol production by immobilized Saccharomyces cerevisiae, Saccharomyces uvarum, and Zymomonas mobilis  

SciTech Connect

Saccharomyces cerevisiae NRRL Y-2034, Saccharomyces uvarum NRRL Y-1347, and Zymomonas mobilis NRRL B-806 each were separately immobilized in a Ca-alginate matrix and incubated in the presence of a free-flowing and continuous 1,3,5, 10, or 20% (w/w) glucose solution. In general, the yeast cells converted 100% of the 1,3, and 5% glucose to alcohol within 48 h and maintained such a conversion rate for at least two weeks. The bacterium converted ca. 90% (w/w) of the 1,3, and 5% glucose to alcohol continuously for one week. However, both the yeast and bacterium were inhibited in the highest glucose (20% w/w) solution. All of the immobilized cultures produced some alcohol for at least 14 days. Immobilized Saccharomyces cerevisiae was the best alcohol producer of all of the glucose concentrations; the yeast yielded 4.7 g ethanol/100 g solution within 72 h in the 10% glucose solution. After 7-8 days in the 10% solution, Saccharomyces cerevisiae produced ethanol at 100% of theoretical yield (5.0 g ethanol/100g solution), with a gradual decrease in alcohol production by 14 days. Immobilized Saccharomyces uvarum produced a maximum of 4.0 g ethanol/100 g solution within 2 days and then declined to ca. 1.0 g ethanol/100g solution after 7 days continuous fermentation in the 10% glucose solution. Zymomonas mobilis reached its maximum ethanol production at 4 days (4.7 g/100 g solution), and then diminished similarly to Saccharomyces uvarum. The development of a multiple disk shaft eliminated the problem both of uneven distribution of alginate-encapsulated cells and of glucose channeling within the continuous-flow fermentor column. This invention improved alcohol production about threefold for the yeast cells. (Refs. 13).

McGhee, J.E.; St. Julian, G.; Detroy, R.W.; Bothast, R.J.

1982-05-01

93

The Inhibiting Effect of Natamycin on the Saccharomyces cerevisiaes and Its Application to the Detection of Beer-Spoilage Bacteria  

Microsoft Academic Search

Natamycin is a safe polyene antifungal compound. This paper investigated the inhibiting effect of natamycin on Saccharomyces cerevisiaes. The results showed that the minimum inhibitory concentrations of natamycin on Saccharomyces cerevisiae S101 and Saccharomyces cerevisiae S201 were 9ppm and 7ppm, respectively. Natamycin was used to detect the beer- spoilage bacteria in the process of beer production. The results indicated that

Cong Nie; Changlu Wang

2011-01-01

94

Frequency and Significance of Antibodies to Saccharomyces cerevisiae in Autoimmune Hepatitis  

Microsoft Academic Search

Our aims were to determine the frequency of antibodies to Saccharomyces cerevisiae in autoimmune hepatitis and assess associations with concurrent mucosal diseases, genetic factors, and corticosteroid response. Seropositivity was determined by enzyme immunoassay in 385 samples obtained from 178 patients. Antibodies to Saccharomyces cerevisiae were detected in 49 patients (28%), and serum levels of immunoglobulin A were higher in seropositive

Albert J. Czaja; Zakera Shums; Peter T. Donaldson; Gary L. Norman

2004-01-01

95

[Mitochondria inheritance in yeast saccharomyces cerevisiae].  

PubMed

The review is devoted to the main mechanisms of mitochondria inheritance in yeast Saccharonmyces cerevisiae. The genetic mechanisms of functionally active mitochondria inheritance in eukaryotic cells is one of the most relevant in modem researches. A great number of genetic diseases are associated with mitochondria dysfunction. Plasticity of eukaryotic cell metabolism according to the environmental changes is ensured by adequate mitochondria functioning by means of ATP synthesis coordination, reactive oxygen species accumulation, apoptosis regulation and is an important factor of cell adaptation to stress. Mitochondria participation in important for cell vitality processes masters the presence of accurate mechanisms of mitochondria functions regulation according to environment fluctuations. The mechanisms of mitochondria division and distribution are highly conserved. Baker yeast S. cerevisiae is an ideal model object for mitochondria researches due to energetic metabolism lability, ability to switch over respiration to fermentation, and petite-positive phenotype. Correction of metabolism according to the environmental changes is necessary for cell vitality. The influence of respiratory, carbon, amino acid and phosphate metabolism on mitochondria functions was shown. As far as the mechanisms that stabilize functions of mitochondria and mtDNA are highly conserve, we can project yeast regularities on higher eukaryotes systems. This makes it possible to approximate understanding the etiology and pathogenesis of a great number of human diseases. PMID:21786681

Fizikova, A Iu

2011-01-01

96

Advanced biofuel production by the yeast Saccharomyces cerevisiae.  

PubMed

Replacement of conventional transportation fuels with biofuels will require production of compounds that can cover the complete fuel spectrum, ranging from gasoline to kerosene. Advanced biofuels are expected to play an important role in replacing fossil fuels because they have improved properties compared with ethanol and some of these may have the energy density required for use in heavy duty vehicles, ships, and aviation. Moreover, advanced biofuels can be used as drop-in fuels in existing internal combustion engines. The yeast cell factory Saccharomyces cerevisiae can be turned into a producer of higher alcohols (1-butanol and isobutanol), sesquiterpenes (farnesene and bisabolene), and fatty acid ethyl esters (biodiesel), and here we discusses progress in metabolic engineering of S. cerevisiae for production of these advanced biofuels. PMID:23628723

Buijs, Nicolaas A; Siewers, Verena; Nielsen, Jens

2013-06-01

97

Direct evidence for a xylose metabolic pathway in Saccharomyces cerevisiae  

SciTech Connect

Xylose transport, xylose reductase, and xylitol dehydrogenase activities are demonstrated in Saccharomyces cerevisiae. The enzymes in the xylose catabolic pathway necessary for the conversion of xylose xylulose are present, although S. cerevisiae cannot grow on xylose as a sole carbon source. Xylose transport is less efficient than glucose transport, and its rate is dependent upon aeration. Xylose reductase appears to be a xylose inducible enzyme and xylitol dehydrogenase activity is constitutive, although both are repressed by glucose. Both xylose reductase and xylitol dehydrogenase activities are five- to tenfold lower in S. cerevisie as compared to Candida utilis. In vivo conversion of /sup 14/C-xylose in S. cerevisiage is demonstrated and xylitol is detected, although no significant levels of any other /sup 14/C-labeled metabolites (e.g., ethanol) are observed. 22 references.

Batt, C.A.; Carvallo, S.; Easson, D.D.; Akedo, M.; Sinskey, A.J.

1986-04-01

98

Sodium azide-induced mutagenesis in Saccharomyces cerevisiae.  

PubMed

Sodium azide (0.5--2.0 X 10(-5) M), applied for 24 h on cells growing in complete medium, increased up to 26 times the frequency of reversions and locus-specific suppressor mutations of allele ilv1-92 in diploid strain D7 of Saccharomyces cerevisiae. Similarly, it enhanced the frequency of reversions and/or mitotic gene conversions of alleles trp5-12/trp5-27 up to 19 times. Reconstruction experiments showed that the increase of mutations in complete medium was not due to a selection of prototrophic types under growth conditions and, therefore, that sodium azide acts as a weak mutagen in S. cerevisiae under growth conditions at a low pH. No mutagenic or convertogenic effect was observed when azide was applied to resting cells in buffer at pH 4.2. PMID:39251

Silhnkov, L; Smiovsk, V; Velemnsk, J

1979-07-01

99

Expression of acylphosphatase in Saccharomyces cerevisiae enhances ethanol fermentation rate  

SciTech Connect

Previous experiments in vitro have demonstrated the ability of acylphosphatase to increase the rate of glucose fermentation in yeast. To evaluate the possibility of increasing fermentation in vivo also, a chemically synthesized DNA sequence coding for human muscle acylphosphatase was expressed at high level in Saccharomyces cerevisiae. Ethanol production was measured in these engineered strains in comparison with a control. Acylphosphatase expression strongly increased the rate of ethanol production both in aerobic and anaerobic culture. This finding may be potentially important for the development of more efficient industrial fermentation processes. 20 refs., 5 figs.

Raugei, G.; Modesti, A.; Magherini, F. [Universita di Firenze (Italy)] [and others

1996-06-01

100

Global analysis of RNA oxidation in Saccharomyces cerevisiae.  

PubMed

Oxidative RNA damage has been linked to loss of RNA function and to the development of many human age-related diseases. Consequently, a need exists for methods to identify and quantify the extent of RNA oxidation on a genome-wide basis. We developed such a method by combining affinity selection of mRNA containing 8-hydroxyguanine with high throughput DNA sequencing. We demonstrate that this assay is suitable for detecting differences in the extent of oxidation between RNA transcripts. We applied this method to the yeast Saccharomyces cerevisiae grown under physiological conditions and in response to hydrogen peroxide, and detected significantly oxidized RNA transcripts. PMID:22313409

McKinlay, Anastasia; Gerard, Wayne; Fields, Stanley

2012-02-01

101

Regulation of parti-tioned sterol biosynthesis in Saccharomyces cerevisiae  

Microsoft Academic Search

Using yeast strains withnull mutations instructural genes whichencode 8-aminolevulinic acidsynthetase (HEM)),isozymes of3-hydroxy-3-methylglutaryl coenzyme A (HMGIandHMG2),squalene epoxidase (ERG)), andfatty acidA9-desaturase (OLEI), wewereabletodetermine theeffect ofhemes,sterols, and unsaturated fatty acids onbothsterol production andthespecific activity of3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR)inSaccharomyces cerevisiae. We foundthattheHMGR isozymes direct essentially equal amounts ofcarbon tothebiosynthesis ofsterols underheme-competent conditions, despite a hugedisparity (57-fold) inthespecific activities ofthereductases. Ourresults demonstrate that palmitoleic

WARREN M. CASEY; GEORGE A. KEESLER; LEO W. PARKS

1992-01-01

102

Transfer RNA splicing in Saccharomyces cerevisiae: defining the substrates.  

PubMed Central

The primary sequences of all the tRNA precursors which contain intervening sequences and which accumulate in the Saccharomyces cerevisiae rnal mutant are presented. A combination of DNA and RNA sequence analysis has led to elucidation of the primary sequence of four hitherto uncharacterized precursors. The location of the intervening sequence has in all cases been unambiguously determined by analysis of the intermediates in the splicing reaction. Secondary structures based upon the tRNA cloverleaf are shown for all the tRNA precursors and discussed with respect to common recognition by the yeast splicing endonuclease. Images

Ogden, R C; Lee, M C; Knapp, G

1984-01-01

103

Tempo and mode of Ty element evolution in Saccharomyces cerevisiae.  

PubMed Central

The Saccharomyces cerevisiae genome contains five families of long terminal repeat (LTR) retrotransposons, Ty1-Ty5. The sequencing of the S. cerevisiae genome provides an unprecedented opportunity to examine the patterns of molecular variation existing among the entire genomic complement of Ty retrotransposons. We report the results of an analysis of the nucleotide and amino acid sequence variation within and between the five Ty element families of the S. cerevisiae genome. Our results indicate that individual Ty element families tend to be highly homogenous in both sequence and size variation. Comparisons of within-element 5' and 3' LTR sequences indicate that the vast majority of Ty elements have recently transposed. Furthermore, intrafamily Ty sequence comparisons reveal the action of negative selection on Ty element coding sequences. These results taken together suggest that there is a high level of genomic turnover of S. cerevisiae Ty elements, which is presumably in response to selective pressure to escape host-mediated repression and elimination mechanisms.

Jordan, I K; McDonald, J F

1999-01-01

104

Construction of strains of Saccharomyces cerevisiae that grow on lactose.  

PubMed Central

We have constructed strains of Saccharomyces cerevisiae that grow on lactose (Lac+). S. cerevisiae strain YNN27, which, like all S. cerevisiae, is unable to grow on lactose, was transformed with pKR1B-LAC4-1. This plasmid has a selectable marker gene conferring resistance to the antibiotic G418 and carries a 13-kilobase region of the Kluyveromyces lactis genome including LAC4, a beta-galactosidase gene. Transformants were selected first for G418 resistance and then for growth on lactose. Southern hybridization experiments showed that Lac+ transformants had integrated 15-25 tandem copies of the vector into a host chromosome. Several lines of evidence indicate that the Lac+ phenotype in pKR1B-LAC4-1-transformed S. cerevisiae is due to expression of a K. lactis lactose permease gene that lies between 2 and 8.6 kilobase upstream of LAC4 and also to expression of LAC4. The permease gene has been designated LAC12. Images

Sreekrishna, K; Dickson, R C

1985-01-01

105

Lis1 Acts as a "Clutch" between the ATPase and Microtubule-Binding Domains of the Dynein Motor  

PubMed Central

Summary The lissencephaly protein Lis1 has been reported to regulate the mechanical behavior of cytoplasmic dynein, the primary minus-end-directed microtubule motor. However, the regulatory mechanism remains poorly understood. Here, we address this issue using purified proteins from Saccharomyces cerevisiae and a combination of techniques, including single-molecule imaging and single-particle electron microscopy. We show that rather than binding to the main ATPase site within dynein's AAA+ ring or its microtubule-binding stalk directly, Lis1 engages the interface between these elements. Lis1 causes individual dynein motors to remain attached to microtubules for extended periods, even during cycles of ATP hydrolysis that would canonically induce detachment. Thus, Lis1 operates like a clutch that prevents dynein's ATPase domain from transmitting a detachment signal to its track-binding domain. We discuss how these findings provide a conserved mechanism for dynein functions in living cells that require prolonged microtubule attachments.

Huang, Julie; Roberts, Anthony J.; Leschziner, Andres E.; Reck-Peterson, Samara L.

2012-01-01

106

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

PubMed

Yeasts are responsible for several traits in fermented beverages, including wine and beer, and their genetic manipulation is often necessary to improve the quality of the fermentation product. Improvement of wild-type strains of Saccharomyces cerevisiae and Saccharomyces pastorianus is difficult due to their homothallic character and variable ploidy level. Homothallism is determined by the HO gene in S. cerevisiae and the Sc-HO gene in S. pastorianus. In this work, we describe the construction of an HO disruption vector (pDHO) containing an HO disruption cassette and discuss its use in generating heterothallic yeast strains from homothallic Saccharomyces species. PMID:22569757

Blasco, Luca; Veiga-Crespo, Patricia; Vias, Miquel; Villa, Toms G

2011-12-01

107

Phylogenetic analysis of the Saccharomyces cerevisiae group based on polymorphisms of rDNA spacer sequences.  

PubMed

The phylogenetic relationships between species of yeasts assigned to the Saccharomyces sensu stricto group, which includes Saccharomyces cerevisiae and Saccharomyces bayanus, were studied together with Saccharomyces pastorianus and Saccharomyces paradoxus. The experimental approaches used were RFLP analysis of the PCR-amplified rDNA internal transcribed spacer (ITS) and intergenic spacer, and total ITS sequence analysis. Both RFLP and sequence analyses gave fairly similar results. The gene trees generated with either of the two data sets showed the distribution of the yeasts into two major, well-separated, phylogenetic clusters called 'cerevisiae' and 'bayanus'. The 'cerevisiae' cluster included the S. cerevisiae type strain, together with most of the species (16 out of 23), whereas the 'bayanus' cluster included the remaining seven type strains. Therefore, analysis of rDNA sequences confirmed S. cerevisiae and S. bayanus as two well-defined taxa. However, S. pastorianus and S. paradoxus, the two other usually accepted taxa of the now-defined Saccharomyces sensu stricto complex, could not be clearly separated from S. bayanus and S. cerevisiae, respectively. However, in both PCR-RFLP and ITS sequence analyses, S. paradoxus had the outermost position in the 'cerevisiae' cluster. PCR-RFLP analysis of the ribosomal spacer sequences was also carried out on 26 Saccharomyces strains isolated in various wine-growing regions of France in an attempt to clarify their positions in the Saccharomyces phylogenetic tree. Compared to the diversity of the Saccharomyces type strains, less genetic diversity was detected among these yeasts and several of them exhibited identical RFLP patterns. Most of the wine yeast strains (16 out of 26) were closely related to each other and were found within the 'cerevisiae' cluster. The remaining 10 wine yeast strains branched within the 'bayanus' cluster. PCR-RFLP analysis of ribosomal spacer sequences thus appears to be a useful and appropriate method for the correct characterization of Saccharomyces yeast strains used in food processing. PMID:9542100

Montrocher, R; Verner, M C; Briolay, J; Gautier, C; Marmeisse, R

1998-01-01

108

Integrated analysis of metabolic phenotypes in Saccharomyces cerevisiae  

PubMed Central

Background The yeast Saccharomyces cerevisiae is an important microorganism for both industrial processes and scientific research. Consequently, there have been extensive efforts to characterize its cellular processes. In order to fully understand the relationship between yeast's genome and its physiology, the stockpiles of diverse biological data sets that describe its cellular components and phenotypic behavior must be integrated at the genome-scale. Genome-scale metabolic networks have been reconstructed for several microorganisms, including S. cerevisiae, and the properties of these networks have been successfully analyzed using a variety of constraint-based methods. Phenotypic phase plane analysis is a constraint-based method which provides a global view of how optimal growth rates are affected by changes in two environmental variables such as a carbon and an oxygen uptake rate. Some applications of phenotypic phase plane analysis include the study of optimal growth rates and of network capacity and function. Results In this study, the Saccharomyces cerevisiae genome-scale metabolic network was used to formulate a phenotypic phase plane that displays the maximum allowable growth rate and distinct patterns of metabolic pathway utilization for all combinations of glucose and oxygen uptake rates. In silico predictions of growth rate and secretion rates and in vivo data for three separate growth conditions (aerobic glucose-limited, oxidative-fermentative, and microaerobic) were concordant. Conclusions Taken together, this study examines the function and capacity of yeast's metabolic machinery and shows that the phenotypic phase plane can be used to accurately predict metabolic phenotypes and to interpret experimental data in the context of a genome-scale model.

Duarte, Natalie C; Palsson, Bernhard ?; Fu, Pengcheng

2004-01-01

109

Transformations of inorganic mercury by Candida albicans and Saccharomyces cerevisiae  

SciTech Connect

Saccharomyces cerevisiae and Candida albicans were incubated with 0.25, 0.5, or 0.75 {mu}g of Hg (as HgCl{sub 2}) per ml of Nelson's medium in the presence of trace amounts of oxygen at 28{degree}C for 12 days. Two control media were used, one without added Hg and one without yeast inoculum. Yeast cell growth was estimated after 1, 2, 3, and 8 days of incubation. The contents of organomercury in the system and of elemental mercury released from the media and collected in traps were determined at the end of the experiments. The results were as follows: (1) C. albicans was the more mercury-resistant species, but both yeast species failed to grown in the media containing 0.75 {mu}g of Hg per ml.; (2) The amounts of organomercury produced by the two species were proportional to the amount of HgCl{sub 2} added to the medium. In all cases C. albicans produced considerably larger amounts of methylmercury than S. cerevisiae; (3) The amounts of elemental Hg produced were inversely proportional to the HgCl{sub 2} level added in the case of S. cerevisiae but were all similar in the case of C. albicans;and (4) Neither organomercury nor elemental Hg was produced in any of the control media.

Yannai, S.; Berdicevsky, I.; Duek, L. (Technion-Israel Institute of Technology, Haifa (Israel))

1991-01-01

110

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

111

Properties of yeast Saccharomyces cerevisiae plasma membrane dicarboxylate transporter.  

PubMed

Transport of succinate into Saccharomyces cerevisiae cells was determined using the endogenous coupled mitochondrial succinate oxidase system. The dependence of succinate oxidation rate on the substrate concentration was a curve with saturation. At neutral pH the K(m) value of the mitochondrial "succinate oxidase" was fivefold less than that of the cellular "succinate oxidase". O-Palmitoyl-L-malate, not penetrating across the plasma membrane, completely inhibited cell respiration in the presence of succinate but not glucose or pyruvate. The linear inhibition in Dixon plots indicates that the rate of succinate oxidation is limited by its transport across the plasmalemma. O-Palmitoyl-L-malate and L-malate were competitive inhibitors (the K(i) values were 6.6 +/- 1.3 microM and 17.5 +/- 1.1 mM, respectively). The rate of succinate transport was also competitively inhibited by the malonate derivative 2-undecyl malonate (K(i) = 7.8 +/- 1.2 microM) but not phosphate. Succinate transport across the plasma membrane of S. cerevisiae is not coupled with proton transport, but sodium ions are necessary. The plasma membrane of S. cerevisiae is established to have a carrier catalyzing the transport of dicarboxylates (succinate and possibly L-malate and malonate). PMID:17125465

Aliverdieva, D A; Mamaev, D V; Bondarenko, D I; Sholtz, K F

2006-10-01

112

Production of aromatics in Saccharomyces cerevisiae--a feasibility study.  

PubMed

Aromatics are amongst the most important bulk feedstocks for the chemical industry, however, no viable bioprocess exists today and production is still dependent on petro-chemistry. In this article the production of aromatic precursors such as p-hydroxybenzoic acid (PHBA) and p-amino benzoic acid (PABA) in Saccharomyces cerevisiae was evaluated using metabolic network analysis. Theoretical mass yields for PHBA and for PABA obtained by metabolic network analysis were 0.58 and 0.53 g g(glucose)?, respectively. A major setback for microbial production of aromatics is the high toxicity of the products. Therefore, PHBA and PABA toxicity was evaluated in S. cerevisiae. Minimal inhibitory concentrations of 38.3 g L? for PHBA and 0.62 g L? for PABA were observed. However, PABA toxicity could be alleviated in adaptation experiments. Finally, metabolic engineering was used to create proof of principle first generation strains of S. cerevisiae. Overall accumulation of 650 ?M PHBA and 250 ?M PABA could be achieved. PMID:22579724

Krmer, Jens O; Nunez-Bernal, Dariela; Averesch, Nils J H; Hampe, Jennifer; Varela, Javier; Varela, Cristian

2013-01-20

113

Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae  

PubMed Central

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

Vemuri, G. N.; Eiteman, M. A.; McEwen, J. E.; Olsson, L.; Nielsen, J.

2007-01-01

114

Sucrose fermentation by Saccharomyces cerevisiae lacking hexose transport.  

PubMed

Sucrose is the major carbon source used by Saccharomyces cerevisiae during production of baker's yeast, fuel ethanol and several distilled beverages. It is generally accepted that sucrose fermentation proceeds through extracellular hydrolysis of the sugar, mediated by the periplasmic invertase, producing glucose and fructose that are transported into the cells and metabolized. In the present work we analyzed the contribution to sucrose fermentation of a poorly characterized pathway of sucrose utilization by S. cerevisiae cells, the active transport of the sugar through the plasma membrane and its intracellular hydrolysis. A yeast strain that lacks the major hexose transporters (hxt1-hxt7 and gal2) is incapable of growing on or fermenting glucose or fructose. Our results show that this hxt-null strain is still able to ferment sucrose due to direct uptake of the sugar into the cells. Deletion of the AGT1 gene, which encodes a high-affinity sucrose-H(+) symporter, rendered cells incapable of sucrose fermentation. Since sucrose is not an inducer of the permease, expression of the AGT1 must be constitutive in order to allow growth of the hxt-null strain on sucrose. The molecular characterization of active sucrose transport and fermentation by S. cerevisiae cells opens new opportunities to optimize yeasts for sugarcane-based industrial processes. PMID:15741738

Batista, Anderson S; Miletti, Luiz C; Stambuk, Boris U

2004-01-01

115

Osmo-, Thermo- and Ethanol- Tolerances of Saccharomyces cerevisiae S1  

PubMed Central

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

Balakumar, Sandrasegarampillai; Arasaratnam, Vasanthy

2012-01-01

116

Saccharomyces cerevisiae chorismate synthase has a flavin reductase activity.  

PubMed

Chorismate synthase (CS) catalyses the conversion of 5-enolpyruvylshikimate 3-phosphate (EPSP) to form chorismate, which is the last common intermediate in the synthesis of the three aromatic amino acids phenylalanine, tyrosine and tryptophan. Despite the overall redox-neutral reaction, catalysis has an absolute requirement for reduced flavin. In the fungus Neurospora crassa, a flavin reductase (FR) activity able to generate reduced flavin mononucleotide in the presence of NADPH is an intrinsic feature of a bifunctional CS. In all bacterial and plant species investigated to date, purified CSs lack an FR activity and are correspondingly 8-10 kDa smaller than the N. crassa CS (on the basis of SDS-PAGE). The cloning of N. crassa CS and subsequent characterization of the purified heterologously expressed enzyme indicates that, surprisingly, the FR probably resides within a region conserved amongst both mono- and bifunctional CSs and is not related to non-homologous sequences which contribute to the larger molecular mass of the N. crassa CS. This information directed this work towards the smaller Saccharomyces cerevisiae CS, the sequence of which was known, although the protein has not been extensively characterized biochemically. Here the characterization of the S. cerevisiae CS is reported in more detail and it is shown that the protein is also bifunctional. With this knowledge, S. cerevisiae could be used as a genetic system for studying the physiological consequences of bifunctionality. The phylogenetic relationship amongst known CSs is discussed. PMID:8971708

Henstrand, J M; Schaller, A; Braun, M; Amrhein, N; Schmid, J

1996-12-01

117

De novo synthesis of monoterpenes by Saccharomyces cerevisiae wine yeasts.  

PubMed

This paper reports the production of monoterpenes, which elicit a floral aroma in wine, by strains of the yeast Saccharomyces cerevisiae. Terpenes, which are typical components of the essential oils of flowers and fruits, are also present as free and glycosylated conjugates amongst the secondary metabolites of certain wine grape varieties of Vitis vinifera. Hence, when these compounds are present in wine they are considered to originate from grape and not fermentation. However, the biosynthesis of monoterpenes by S. cerevisiae in the absence of grape derived precursors is shown here to be of de novo origin in wine yeast strains. Higher concentration of assimilable nitrogen increased accumulation of linalool and citronellol. Microaerobic compared with anaerobic conditions favored terpene accumulation in the ferment. The amount of linalool produced by some strains of S. cerevisiae could be of sensory importance in wine production. These unexpected results are discussed in relation to the known sterol biosynthetic pathway and to an alternative pathway for terpene biosynthesis not previously described in yeast. PMID:15668008

Carrau, Francisco M; Medina, Karina; Boido, Eduardo; Farina, Laura; Gaggero, Carina; Dellacassa, Eduardo; Versini, Giuseppe; Henschke, Paul A

2005-02-01

118

Filamentous growth of Saccharomyces cerevisiae is regulated by manganese.  

PubMed

The Candida albicans INT1 gene is a virulence factor that contributes to both adhesion and filamentous growth of the fungus. Expression of INT1 in the budding yeast Saccharomyces cerevisiae directs both adhesion and filamentous growth. Because Int1p contains two predicted divalent cation-binding motifs, we asked whether divalent cations are important for the role of Int1p in filament formation. In this study, we found that INT1-induced filamentous growth (I-IFG) is sensitive to the divalent cation chelator EDTA and that this EDTA sensitivity can be ameliorated by the addition of Mn(2+), but not Mg(2+) or Ca(2+) ions. The addition of MnCl(2) restored both the proportion of cells forming filaments and the length of filaments formed. Expression of INT1 in S. cerevisiae mutants that reduce the intracellular concentration of Mn(2+) did not affect I-IFG. Interestingly, the Mn(2+) dependence of I-IFG is not dependent upon the presence of the putative divalent cation-binding domains found in INT1. Rather, we found that polarized growth induced by mutations in CDC12 and CLA4 or by expression of excess SWE1 was also sensitive to EDTA treatment and was restored by the addition of MnCl(2) but not by the addition of CaCl(2). Thus, our results suggest that in S. cerevisiae polarized growth is dependent upon the presence of Mn(2+) ions. PMID:11017771

Asleson, C M; Asleson, J C; Malandra, E; Johnston, S; Berman, J

2000-07-01

119

Ethanol production by Saccharomyces cerevisiae in biofilm reactors.  

PubMed

Biofilms are natural forms of cell immobilization in which microorganisms attach to solid supports. At ISU, we have developed plastic composite-supports (PCS) (agricultural material (soybean hulls or oat hulls), complex nutrients, and polypropylene) which stimulate biofilm formation and which supply nutrients to the attached microorganisms. Various PCS blends were initially evaluated in repeated-batch culture-tube fermentation with Saccharomyces cerevisiae (ATCC 24859) in low organic nitrogen medium. The selected PCS (40% soybean hull, 5% soybean flour, 5% yeast extract-salt and 50% polypropylene) was then used in continuous and repeated-batch fermentation in various media containing lowered nitrogen content with selected PCS. During continuous fermentation, S. cerevisiae demonstrated two to 10 times higher ethanol production in PCS bioreactors than polypropylene-alone support (PPS) control. S. cerevisiae produced 30 g L-1 ethanol on PCS with ammonium sulfate medium in repeated batch fermentation, whereas PPS-control produced 5 g L-1 ethanol. Overall, increased productivity in low cost medium can be achieved beyond conventional fermentations using this novel bioreactor design. PMID:9439005

Demirci, A; Pometto, A L; Ho, K L

1997-10-01

120

An assay for functional xylose transporters in Saccharomyces cerevisiae.  

PubMed

It has been considered that more efficient uptake of xylose could promote increased xylose metabolic capacity of several microorganisms. In this study, an assay to screen xylose transporters was established in the Saccharomyces cerevisiae strain, which expresses the xylosidase gene of Bacillus pumilus intracellularly. The absorbed xylose analog p-nitrophenyl-?-d-xylopyranoside (pNPX) rapidly hydrolyzed to p-nitrophenol (pNP), which displayed a yellow tint when exposed to xylosidase in vivo. The xylose transporter activities of the strain were computed using the pNP production rate, which was detected extracellularly. This method could be used for both high-throughput screening and smaller scale investigations. AraEp, which is a pentose transporter of Corynebacterium glutamicum, was expressed in S. cerevisiae and exhibited better transport capacity than the endogenous transporters Hxt7p and Gal2p. Moreover, a mutant of AraEp with 103% greater transport capacity was screened out, and the computer simulation suggested that transmembrane domain 5 was an important factor for the transport capacity of AraEp in S. cerevisiae. PMID:23928049

Wang, Chengqiang; Shen, Yu; Hou, Jin; Suo, Fan; Bao, Xiaoming

2013-11-15

121

Adenylate energy charge in Saccharomyces cerevisiae during starvation.  

PubMed Central

Bakers' yeast cells, Saccharomyces cerevisiae, if grown aerobically on ethanol or if grown aerobically on glucose and allowed to pass into stationary phase, with utilization of accumulated ethanol, maintain a normal value (0.8 to 0.9) of the adenylate energy charge during prolonged starvation. In contrast, cells grown anaerobically on glucose and cells in the early stages of aerobic growth on glucose exhibit a rapid decrease of energy charge if transferred to medium lacking on energy source. These results suggest that functional mitochondria or enzymes of balance of adenine nucleotides during starvation. Yeast cells remain viable at energy charge values below 0.1, in marked contrast to results previously obtained with Escherichia coli. In other respects, the engery charge responses of yeast to starvation and refeeding are generally similar to those previously reported for E. coli.

Ball, W J; Atkinson, D E

1975-01-01

122

The influence of microgravity on invasive growth in Saccharomyces cerevisiae.  

PubMed

This study investigates the effects of microgravity on colony growth and the morphological transition from single cells to short invasive filaments in the model eukaryotic organism Saccharomyces cerevisiae. Two-dimensional spreading of the yeast colonies grown on semi-solid agar medium was reduced under microgravity in the ?1278b laboratory strain but not in the CMBSESA1 industrial strain. This was supported by the ?1278b proteome map under microgravity conditions, which revealed upregulation of proteins linked to anaerobic conditions. The ?1278b strain showed a reduced invasive growth in the center of the yeast colony. Bud scar distribution was slightly affected, with a switch toward more random budding. Together, microgravity conditions disturb spatially programmed budding patterns and generate strain-dependent growth differences in yeast colonies on semi-solid medium. PMID:21345087

Van Mulders, Sebastiaan E; Stassen, Catherine; Daenen, Luk; Devreese, Bart; Siewers, Verena; van Eijsden, Rudy G E; Nielsen, Jens; Delvaux, Freddy R; Willaert, Ronnie

2011-01-01

123

Modeling growth and telomere dynamics in Saccharomyces cerevisiae  

PubMed Central

A general branching process is proposed to model a population of cells of the yeast Saccharomyces cerevisiae following loss of telomerase. Previously published experimental data indicate that a population of telomerase-deficient cells regain exponential growth after a period of slowing due to critical telomere shortening. The explanation for this phenomenon is that some cells engage telomerase-independent pathways to maintain telomeres that allow them to become survivors. Our model takes into account random variation in individual cell cycle times, telomere length, finite replicative lifespan of mother cells, and survivorship. We identify and estimate crucial parameters such as the probability of an individual cell becoming a survivor, and compare our model predictions to experimental data.

Bertuch, Alison A.

2013-01-01

124

Glucose transport in a kinaseless Saccharomyces cerevisiae mutant.  

PubMed Central

Wild-type Saccharomyces cerevisiae organisms contain three kinases which catalyze the phosphorylation of glucose: two hexokinase isozymes (PI and PII) and one glucokinase. Glucose transport measurements for triple-kinaseless mutants, which lack all three of these kinases, confirm that the kinases are involved in the low apparent Km transport process observed in metabolizing cells. Thus kinase-positive cells containing one or more of the three kinases exhibit biphasic transport kinetics with a low apparent Km (1 to 2 mM) and high apparent Km (40 to 50 mM) component. Triple-kinaseless cells, however, exhibit only the high apparent Km component of kinase-positive cells (60 mM). Kinetic analysis of glucose transport in the triple-kinaseless cells shows that glucose is transported by a facilitated diffusion process which exhibits trans-stimulated equilibrium exchange and influx counterflow.

Lang, J M; Cirillo, V P

1987-01-01

125

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

126

Modeling and optimization of cloned invertase expression in Saccharomyces cerevisiae.  

PubMed

The aim of this study is to determine the medium feeding strategy to maximize the invertase productivity of recombinant Saccharomyces Cerevisiae using a fed-batch mode of operation. The yeast contains the plasmid, pRB58, which contains the yeast SUC2 gene, coding for the enzyme invertase. The expression of this gene is repressed at high glucose levels. A Goal-oriented model is development to describe the kinetics of fed-batch fermentations. This simple model could quantitatively describe previous experimental results. A conjugate gradient algorithm is then used, in conjunction gradient algorithm is then used, in conjunction with this mathematical model, to compute the optimum feed rate for maximization of invertase productivity. The optimal feeding procedure results in an initial high cell growth phase followed by a high invertase production phase. PMID:18601292

Patkar, A; Seo, J H; Lim, H C

1993-05-01

127

Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

128

Biochemical and regulatory effects of methionine analogues in Saccharomyces cerevisiae.  

PubMed Central

The effect of three methionine analogues, ethionine, selenomethionine, and trifluoromethionine, on the biosynthesis of methionine in Saccharomyces cerevisiae has been investigated. We have found the following to be true. (i) A sharp decrease in the endogenous methionine concentration occurs after the addition of any one of these analogues to growing cells. (ii) All of them can be transferred to methionine transfer ribonucleic acid in vitro as well as in vivo with, as a consequence, their incorporation into proteins. In the absence of radioactive trifluoromethionine, this conclusion results from experiments of an indirect nature and must be taken as an indication rather than a direct demonstration. (iii) Ethionine and selenomethionine can be activated as homologues of S-adenosylmethionine, whereas trifluoromethionine cannot. (iv) All of them can act as repressors of the methionine biosynthetic pathway. This has been shown by measuring the de novo rate of synthesis of methionine in a culture grown in the presence of any one of the three analogues.

Colombani, F; Cherest, H; de Robichon-Szulmajster, H

1975-01-01

129

Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress.  

PubMed

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 S, 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

130

Availability of substratum enhances ethanol production in Saccharomyces cerevisiae.  

PubMed

Novel additives that act as substratum for attachment of the yeast cells, increased ethanol production in Saccharomyces cerevisiae. The addition of 2 g rice husk, straw, wood shavings, plastic pieces or silica gel to 100 ml medium enhanced ethanol production by 30-40 (v/v). Six distillery strains showed an average enhancement of 34 from 4.1 (v/v) in control to 5.5 (v/v) on addition of rice husk. The cell wall bound glycogen increased by 40-50 mg g (-1) dry yeast while intracellular glycogen decreased by 10-12 mg g(-1) dry yeast in cells grown in presence of substratum. PMID:15672221

Sankh, Santosh N; Arvindekar, Akalpita U

2004-12-01

131

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.

de Sa, 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

132

Metal ion transport in eukaryotic microorganisms: insights from Saccharomyces cerevisiae.  

PubMed

Metal ions such as iron, copper, manganese, and zinc are essential nutrients for all eukaryotic microorganisms. Therefore, these organisms possess efficient uptake mechanisms to obtain these nutrients from their extracellular environment. Metal ions must also be transported into intracellular organelles where they function as catalytic and structural cofactors for compartmentalized enzymes. Thus, intracellular transport mechanisms are also present. When present in high levels, metal ions can also be toxic, so their uptake and intracellular transport is tightly regulated at both transcriptional and post-transcriptional levels to limit metal ion overaccumulation and facilitate storage and sequestration. Remarkable molecular insight into these processes has come from recent studies of the yeast Saccharomyces cerevisiae. This organism, which is the primary subject of this chapter, serves as a useful paradigm to understand metal ion metabolism in other eukaryotic microbes. PMID:10907553

Eide, D J

2000-01-01

133

Higher-order structure of Saccharomyces cerevisiae chromatin  

SciTech Connect

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

Lowary, P.T.; Widom, J. (Univ. of Illinois, Urbana (USA))

1989-11-01

134

Interaction among Saccharomyces cerevisiae pheromone receptors during endocytosis.  

PubMed

This study investigates endocytosis of Saccharomyces cerevisiae ?-factor receptor and the role that receptor oligomerization plays in this process. ?-factor receptor contains signal sequences in the cytoplasmic C-terminal domain that are essential for ligand-mediated endocytosis. In an endocytosis complementation assay, we found that oligomeric complexes of the receptor undergo ligand-mediated endocytosis when the ?-factor binding site and the endocytosis signal sequences are located in different receptors. Both in vitro and in vivo assays suggested that ligand-induced conformational changes in one Ste2 subunit do not affect neighboring subunits. Therefore, recognition of the endocytosis signal sequence and recognition of the ligand-induced conformational change are likely to be two independent events. PMID:24682008

Chang, Chien-I; Schandel, Kimberly A; Jenness, Duane D

2014-01-01

135

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

136

The mannoprotein of Saccharomyces cerevisiae is an effective bioemulsifier.  

PubMed Central

The mannoprotein which is a major component of the cell wall of Saccharomyces cerevisiae is an effective bioemulsifier. Mannoprotein emulsifier was extracted in a high yield from whole cells of fresh bakers' yeast by two methods, by autoclaving in neutral citrate buffer and by digestion with Zymolase (Miles Laboratories; Toronto, Ontario, Canada), a beta-1,3-glucanase. Heat-extracted emulsifier was purified by ultrafiltration and contained approximately 44% carbohydrate (mannose) and 17% protein. Treatment of the emulsifier with protease eliminated emulsification. Kerosene-in-water emulsions were stabilized over a broad range of conditions, from pH 2 to 11, with up to 5% sodium chloride or up to 50% ethanol in the aqueous phase. In the presence of a low concentration of various solutes, emulsions were stable to three cycles of freezing and thawing. An emulsifying agent was extracted from each species or strain of yeast tested, including 13 species of genera other than Saccharomyces. Spent yeast from the manufacture of beer and wine was demonstrated to be a possible source for the large-scale production of this bioemulsifier.

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

1988-01-01

137

A series of protein phosphatase gene disruptants in Saccharomyces cerevisiae.  

PubMed

Thirty-two protein phosphatase (PPase) genes were identified in the genome nucleotide sequence of Saccharomyces cerevisiae. We constructed S. cerevisiae disruptants for each of the PPase genes and examined their growth under various conditions. The disruptants of six putative PPase genes, i.e. of YBR125c, YCR079w, YIL113w, YJR110w, YNR022c and YOR090c, were created for the first time in this study. The glc7, sit4 and cdc14 disruptants were lethal in our strain background. The remaining 29 PPase gene disruptants were viable at 30 degrees C and 37 degrees C, but only one disruptant, yvh1, showed intrinsic cold-sensitive growth at 13 degrees C. Transcription of the YVH1 gene was induced at 13 degrees C, consistent with an idea that Yvh1p has a specific role for growth at a low temperature. The viable disruptants grew normally on nutrient medium containing sucrose, galactose, maltose or glycerol as carbon sources. The ppz1 disruptant was tolerant to NaCl and LiCl, while the cmp2 disruptant was sensitive to these salts, as reported previously, and none of the other viable PPase disruptants exhibited the salt sensitivity. When the viable disruptants were tested for sensitivity to drugs, i.e. benomyl, caffeine and hydroxyurea, ppz1 and ycr079w disruptants exhibited sensitivity to caffeine. PMID:10572263

Sakumoto, N; Mukai, Y; Uchida, K; Kouchi, T; Kuwajima, J; Nakagawa, Y; Sugioka, S; Yamamoto, E; Furuyama, T; Mizubuchi, H; Ohsugi, N; Sakuno, T; Kikuchi, K; Matsuoka, I; Ogawa, N; Kaneko, Y; Harashima, S

1999-11-01

138

Ras proteins control mitochondrial biogenesis and function in Saccharomyces cerevisiae.  

PubMed

The evolutionarily conserved Ras proteins function as a point of convergence for different signaling pathways in eukaryotes and have been implicated in both aging and cancer development. In Saccharomyces cerevisiae the plasma membrane proteins Ras1 and Ras2 are sensing the nutritional status of the environments, e.g., the abundance and quality of available carbon sources. The cAMP-protein kinase A pathway is the most explored signaling pathway controlled by Ras proteins; it affects a large number of genes, some of which are important to defend the cell against oxidative stress. In addition, recent analysis has shown that the Ras system of yeast is involved in the development of mitochondria and in regulating their activity. As a sensor of environmental status and an effector of mitochondrial activity, Ras serves as a Rosetta stone of cellular energy transduction. This review summarizes the physical and functional involvement of Ras proteins and Ras-dependent signaling pathways in mitochondrial function in S. cerevisiae. Since mitochondria produce harmful reactive oxygen species as an inevitable byproduct and are partly under control of Ras, illuminating these regulatory interactions may improve our understanding of both cancer and aging. PMID:15058183

Hlavat, L; Nystrm, T

2003-01-01

139

MPR1 as a novel selection marker in Saccharomyces cerevisiae.  

PubMed

L-Azetidine-2-carboxylic acid (AZC) is a toxic four-membered ring analogue of L-proline that is transported into cells by proline transporters. AZC and L-proline in the cells are competitively incorporated into nascent proteins. When AZC is present in a minimum medium, misfolded proteins are synthesized in the cells, thereby inhibiting cell growth. The MPR1 gene has been isolated from the budding yeast Saccharomyces cerevisiae Sigma1278b as a multicopy suppressor of AZC-induced growth inhibition. MPR1 encodes a novel acetyltransferase that detoxifies AZC via N-acetylation. Since MPR1 is absent in the laboratory strain of S. cerevisiae S288C, it could be a positive selection marker that confers AZC resistance in the S288C background strains. To examine the usefulness of MPR1, we constructed some plasmid vectors that harboured MPR1 under the control of various promoters and introduced them into the S288C-derived strains. The expression of MPR1 conferred AZC resistance that was largely dependent on the expression level of MPR1. In an additional experiment, the galactose-inducible MPR1 and ppr1(+), the fission yeast Schizosaccharomyces pombe homologue of MPR1, were used for gene disruption by homologous recombination, and here AZC-resistant colonies were also successfully selected. We concluded that our MPR1-AZC system provides a powerful tool for yeast transformation. PMID:19750564

Ogawa-Mitsuhashi, Kaoru; Sagane, Koji; Kuromitsu, Junro; Takagi, Hiroshi; Tsukahara, Kappei

2009-11-01

140

ELM1 Is Required for Multidrug Resistance in Saccharomyces cerevisiae  

PubMed Central

In Saccharomyces cerevisiae, transcription of several drug transporter genes, including the major transporter gene PDR5, has been shown to peak during mitosis. The significance of this observation, however, remains unclear. PDR1 encodes the primary transcription activator of multiple drug transporter genes in S. cerevisiae, including PDR5. Here, we show that in synchronized PDR1 and pdr1-3 (multidrug resistant) strains, cellular efflux of a known substrate of ATP-binding-cassette transporters, doxorubicin (a fluorescent anticancer drug), is highest during mitosis when PDR5 transcription peaks. A genetic screen performed to identify regulators of multidrug resistance revealed that a truncation mutation in ELM1 (elm1-300) suppressed the multidrug resistance of pdr1-3. ELM1 encodes a serine/threonine protein kinase required for proper regulation of multiple cellular kinases, including those involved in mitosis, cytokinesis, and cellular morphogenesis. elm1-300 as well as elm1? mutations in a pdr1-3 strain also caused elongated bud morphology (indicating a G2/M delay) and reduction of PDR5 transcription under induced and noninduced conditions. Interestingly, mutations in several genes functionally related to ELM1, including cla4?, gin4?, and cdc28-C127Y, also caused drastic reductions in drug resistance and PDR5 transcription. Collectively, these data show that ELM1, and genes encoding related serine/threonine protein kinases, are required for regulation of multidrug resistance involving, at least in part, control of PDR5 transcription.

Souid, Abdul-Kader; Gao, Chen; Wang, Luming; Milgrom, Elena; Shen, W.-C. Winston

2006-01-01

141

Sweet wine production by two osmotolerant Saccharomyces cerevisiae strains.  

PubMed

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

Garca-Martnez, Teresa; de Lerma, Nieves Lpez; Moreno, Juan; Peinado, Rafael A; Milln, M Carmen; Mauricio, Juan C

2013-06-01

142

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.

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

1996-01-01

143

Regulation of partitioned sterol biosynthesis in Saccharomyces cerevisiae.  

PubMed Central

Using yeast strains with null mutations in structural genes which encode delta-aminolevulinic acid synthetase (HEM1), isozymes of 3-hydroxy-3-methylglutaryl coenzyme A (HMG1 and HMG2), squalene epoxidase (ERG1), and fatty acid delta 9-desaturase (OLE1), we were able to determine the effect of hemes, sterols, and unsaturated fatty acids on both sterol production and the specific activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) in Saccharomyces cerevisiae. We found that the HMGR isozymes direct essentially equal amounts of carbon to the biosynthesis of sterols under heme-competent conditions, despite a huge disparity (57-fold) in the specific activities of the reductases. Our results demonstrate that palmitoleic acid (16:1) acts as a rate-limiting positive regulator and that ergosterol acts as a potent inhibitor of sterol production in strains which possess only the HMGR1 isozyme (HMG1 hmg2). In strains which contain only the HMGR2 isozyme (hmg1 HMG2), sterol production was inhibited by oleic acid (18:1) and to a lesser degree by ergosterol. The specific activities of the two reductases (HMGR1 and HMGR2) were found to be differentially regulated by hemes but not by ergosterol, palmitoleic acid, or oleic acid. The disparate effects of unsaturated fatty acids and sterols on these strains lead us to consider the possibility of separate, compartmentalized isoprenoid pathways in S. cerevisiae.

Casey, W M; Keesler, G A; Parks, L W

1992-01-01

144

Coordinated induction of multi-gene pathways in Saccharomyces cerevisiae  

PubMed Central

Bacterial operons are natures tool for regulating and coordinating multi-gene expression in prokaryotes. They are also a gene architecture commonly used in the biosynthesis of many pharmaceutically important compounds and industrially useful chemicals. Despite being an important eukaryotic production host, Saccharomyces cerevisiae has never had such gene architecture. Here, we report the development of a system to assemble and regulate a multi-gene pathway in S. cerevisiae. Full pathways can be constructed using pre-made parts from a plasmid toolbox. Subsequently, through the use of a yeast strain containing a stably integrated gene switch, the assembled pathway can be regulated using a readily available and inexpensive compoundestradiolwith extremely high sensitivity (10 nM). To demonstrate the use of the system, we assembled the five-gene zeaxanthin biosynthetic pathway in a single step and showed the ligand-dependent coordinated expression of all five genes as well as the tightly regulated production of zeaxanthin. Compared with a previously reported constitutive zeaxanthin pathway, our inducible pathway was shown to have 50-fold higher production level.

Liang, Jing; Ning, Jonathan C.; Zhao, Huimin

2013-01-01

145

Characterization of a Saccharomyces cerevisiae mutant with oversecretion phenotype.  

PubMed

An oversecreting mutant of Saccharomyces cerevisiae was obtained from about 400 meiotic segregants derived from thediploid cells made by crossing the HBsAg-induced mutant NI-C with the wild-type strain Sey6211. When transformed with a plasmid containing mouse alpha-amylase cDNA, the mutant (NI-C-D4) exhibited an increased capacity (up to 13-fold) for the secretion of mouse alpha-amylase, higher than the parental strains and other standard wild-type strains. It was also shown that alpha-amylase secreted by the oversecreting mutant had a higher activity and contained more of the non-glycosylated form than the glycosylated form. This isolated oversecreting, low-glycosylation mutant may prove to be a potential S. cerevisiae host for the production of foreign proteins. Further genetic analysis suggested that the mutation responsible for the mutant's oversecretion was partially dominant and that both the oversecretion and low-glycosylation phenotypes were governed by a single chromosome mutation. These pleiotrophic phenotypes may be attributed to a defect in the synthesis of an ER-resident chaperone. PMID:11525619

Wang, B D; Chen, D C; Kuo, T T

2001-06-01

146

Genetic mapping of Ty elements in Saccharomyces cerevisiae.  

PubMed Central

We used transformation to insert a selectable marker at various sites in the Saccharomyces cerevisiae genome occupied by the transposable element Ty. The vector CV9 contains the LEU2+ gene and a portion of the repeated element Ty1-17. Transformation with this plasmid resulted in integration of the vector via a reciprocal exchange using homology at the LEU2 locus or at the various Ty elements that are dispersed throughout the S. cerevisiae genome. These transformants were used to map genetically sites of several Ty elements. The 24 transformants recovered at Ty sites define 19 distinct loci. Seven of these were placed on the genetic map. Two classes of Ty elements were identified in these experiments: a Ty1-17 class and Ty elements different from Ty1-17. Statistical analysis of the number of transformants at each class of Ty elements shows that there is preferential integration of the CV9 plasmid into the Ty1-17 class. Images

Klein, H L; Petes, T D

1984-01-01

147

Reciprocal translocations in Saccharomyces cerevisiae formed by nonhomologous end joining.  

PubMed Central

Reciprocal translocations are common in cancer cells, but their creation is poorly understood. We have developed an assay system in Saccharomyces cerevisiae to study reciprocal translocation formation in the absence of homology. We induce two specific double-strand breaks (DSBs) simultaneously on separate chromosomes with HO endonuclease and analyze the subsequent chromosomal rearrangements among surviving cells. Under these conditions, reciprocal translocations via nonhomologous end joining (NHEJ) occur at frequencies of approximately 2-7 x 10(-5)/cell exposed to the DSBs. Yku80p is a component of the cell's NHEJ machinery. In its absence, reciprocal translocations still occur, but the junctions are associated with deletions and extended overlapping sequences. After induction of a single DSB, translocations and inversions are recovered in wild-type and rad52 strains. In these rearrangements, a nonrandom assortment of sites have fused to the DSB, and their junctions show typical signs of NHEJ. The sites tend to be between open reading frames or within Ty1 LTRs. In some cases the translocation partner is formed by a break at a cryptic HO recognition site. Our results demonstrate that NHEJ-mediated reciprocal translocations can form in S. cerevisiae as a consequence of DSB repair.

Yu, Xin; Gabriel, Abram

2004-01-01

148

Phenotypes of sphingolipid-dependent strains of Saccharomyces cerevisiae.  

PubMed Central

To study sphingolipid function(s) in Saccharomyces cerevisiae, we have investigated the effects of environmental stress on mutant (SLC) strains (R. C. Dickson, G. B. Wells, A. Schmidt, and R. L. Lester, Mol. Cell. Biol. 10:2176-2181, 1990) that either contain or lack sphingolipids, depending on whether they are cultured with a sphingolipid long-chain base. Strains lacking sphingolipid were unable to grow at low pH, at 37 degrees C, or with high salt concentrations in the medium; these environmental stresses are known to inhibit the growth of some S. cerevisiae strains with a defective plasma membrane H(+)-ATPase. We found that sphingolipids were essential for proton extrusion at low pH and furthermore found that cells lacking sphingolipid no longer exhibited net proton extrusion at normal pH after a 1-min exposure to pH 3. Cells lacking sphingolipid appeared to rapidly become almost completely permeable to protons at low pH. The deleterious effects of low pH could be partially prevented by 1 M sorbitol in the suspension of cells lacking sphingolipid. Proton extrusion at normal pH (pH 6) was significantly inhibited at 39 degrees C only in cells lacking sphingolipid. Thus, the product of an SLC suppressor gene permits life without sphingolipids only in a limited range of environments. Outside this range, sphingolipids appear to be essential for maintaining proton permeability barriers and/or for proton extrusion. Images

Patton, J L; Srinivasan, B; Dickson, R C; Lester, R L

1992-01-01

149

Exploring the northern limit of the distribution of Saccharomyces cerevisiae and Saccharomyces paradoxus in North America.  

PubMed

We examined the northern limit of Saccharomyces cerevisiae and Saccharomyces paradoxus in northeast America. We collected 876 natural samples at 29 sites and applied enrichment methods for the isolation of mesophilic yeasts. We uncovered a large diversity of yeasts, in some cases, associated with specific substrates. Sequencing of the ITS1, 5.8S and ITS2 loci allowed to assign 226 yeast strains at the species level, including 41 S.paradoxus strains. Our intensive sampling suggests that if present, S.cerevisiae is rare at these northern latitudes. Our sampling efforts spread across several months of the year revealed that successful sampling increases throughout the summer and diminishes significantly at the beginning of the fall. The data obtained on the ecological context of yeasts corroborate what was previously reported on Pichiaceae, Saccharomycodaceae, Debaryomycetaceae and Phaffomycetaceae yeast families. We identified 24 yeast isolates that could not be assigned to any known species and that may be of taxonomic, medical, or biotechnological importance. Our study reports new data on the taxonomic diversity of yeasts and new resources for studying the evolution and ecology of S.paradoxus. PMID:24119009

Charron, Guillaume; Leducq, Jean-Baptiste; Bertin, Chlo; Dub, Alexandre K; Landry, Christian R

2014-03-01

150

Non-Coding RNA Prediction and Verification in Saccharomyces cerevisiae  

PubMed Central

Non-coding RNA (ncRNA) play an important and varied role in cellular function. A significant amount of research has been devoted to computational prediction of these genes from genomic sequence, but the ability to do so has remained elusive due to a lack of apparent genomic features. In this work, thermodynamic stability of ncRNA structural elements, as summarized in a Z-score, is used to predict ncRNA in the yeast Saccharomyces cerevisiae. This analysis was coupled with comparative genomics to search for ncRNA genes on chromosome six of S. cerevisiae and S. bayanus. Sets of positive and negative control genes were evaluated to determine the efficacy of thermodynamic stability for discriminating ncRNA from background sequence. The effect of window sizes and step sizes on the sensitivity of ncRNA identification was also explored. Non-coding RNA gene candidates, common to both S. cerevisiae and S. bayanus, were verified using northern blot analysis, rapid amplification of cDNA ends (RACE), and publicly available cDNA library data. Four ncRNA transcripts are well supported by experimental data (RUF10, RUF11, RUF12, RUF13), while one additional putative ncRNA transcript is well supported but the data are not entirely conclusive. Six candidates appear to be structural elements in 5? or 3? untranslated regions of annotated protein-coding genes. This work shows that thermodynamic stability, coupled with comparative genomics, can be used to predict ncRNA with significant structural elements.

Kavanaugh, Laura A.; Dietrich, Fred S.

2009-01-01

151

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.

2011-01-01

152

Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae.  

PubMed

The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often low due to limitations of the host strain. Heat shock response (HSR) is an inducible, global, cellular stress response, which facilitates the cell recovery from many forms of stress, e.g., heat stress. In S. cerevisiae, HSR is regulated mainly by the transcription factor heat shock factor (Hsf1p) and many of its targets are genes coding for molecular chaperones that promote protein folding and prevent the accumulation of mis-folded or aggregated proteins. In this work, we over-expressed a mutant HSF1 gene HSF1-R206S which can constitutively activate HSR, so the heat shock response was induced at different levels, and we studied the impact of HSR on heterologous protein secretion. We found that moderate and high level over-expression of HSF1-R206S increased heterologous ?-amylase yield 25 and 70 % when glucose was fully consumed, and 37 and 62 % at the end of the ethanol phase, respectively. Moderate and high level over-expression also improved endogenous invertase yield 118 and 94 %, respectively. However, human insulin precursor was only improved slightly and this only by high level over-expression of HSF1-R206S, supporting our previous findings that the production of this protein in S. cerevisiae is not limited by secretion. Our results provide an effective strategy to improve protein secretion and demonstrated an approach that can induce ER and cytosolic chaperones simultaneously. PMID:23208612

Hou, Jin; Osterlund, Tobias; Liu, Zihe; Petranovic, Dina; Nielsen, Jens

2013-04-01

153

Metabolic engineering of glycerol production in Saccharomyces cerevisiae.  

PubMed

Inactivation of TPI1, the Saccharomyces cerevisiae structural gene encoding triose phosphate isomerase, completely eliminates growth on glucose as the sole carbon source. In tpi1-null mutants, intracellular accumulation of dihydroxyacetone phosphate might be prevented if the cytosolic NADH generated in glycolysis by glyceraldehyde-3-phosphate dehydrogenase were quantitatively used to reduce dihydroxyacetone phosphate to glycerol. We hypothesize that the growth defect of tpi1-null mutants is caused by mitochondrial reoxidation of cytosolic NADH, thus rendering it unavailable for dihydroxyacetone-phosphate reduction. To test this hypothesis, a tpi1delta nde1delta nde2delta gut2delta quadruple mutant was constructed. NDE1 and NDE2 encode isoenzymes of mitochondrial external NADH dehydrogenase; GUT2 encodes a key enzyme of the glycerol-3-phosphate shuttle. It has recently been demonstrated that these two systems are primarily responsible for mitochondrial oxidation of cytosolic NADH in S. cerevisiae. Consistent with the hypothesis, the quadruple mutant grew on glucose as the sole carbon source. The growth on glucose, which was accompanied by glycerol production, was inhibited at high-glucose concentrations. This inhibition was attributed to glucose repression of respiratory enzymes as, in the quadruple mutant, respiratory pyruvate dissimilation is essential for ATP synthesis and growth. Serial transfer of the quadruple mutant on high-glucose media yielded a spontaneous mutant with much higher specific growth rates in high-glucose media (up to 0.10 h(-1) at 100 g of glucose. liter(-1)). In aerated batch cultures grown on 400 g of glucose. liter(-1), this engineered S. cerevisiae strain produced over 200 g of glycerol. liter(-1), corresponding to a molar yield of glycerol on glucose close to unity. PMID:12039737

Overkamp, Karin M; Bakker, Barbara M; Ktter, Peter; Luttik, Marijke A H; Van Dijken, Johannes P; Pronk, Jack T

2002-06-01

154

Stoichiometry and compartmentation of NADH metabolism in Saccharomyces cerevisiae.  

PubMed

In Saccharomyces cerevisiae, reduction of NAD(+) to NADH occurs in dissimilatory as well as in assimilatory reactions. This review discusses mechanisms for reoxidation of NADH in this yeast, with special emphasis on the metabolic compartmentation that occurs as a consequence of the impermeability of the mitochondrial inner membrane for NADH and NAD(+). At least five mechanisms of NADH reoxidation exist in S. cerevisiae. These are: (1) alcoholic fermentation; (2) glycerol production; (3) respiration of cytosolic NADH via external mitochondrial NADH dehydrogenases; (4) respiration of cytosolic NADH via the glycerol-3-phosphate shuttle; and (5) oxidation of intramitochondrial NADH via a mitochondrial 'internal' NADH dehydrogenase. Furthermore, in vivo evidence indicates that NADH redox equivalents can be shuttled across the mitochondrial inner membrane by an ethanol-acetaldehyde shuttle. Several other redox-shuttle mechanisms might occur in S. cerevisiae, including a malate-oxaloacetate shuttle, a malate-aspartate shuttle and a malate-pyruvate shuttle. Although key enzymes and transporters for these shuttles are present, there is as yet no consistent evidence for their in vivo activity. Activity of several other shuttles, including the malate-citrate and fatty acid shuttles, can be ruled out based on the absence of key enzymes or transporters. Quantitative physiological analysis of defined mutants has been important in identifying several parallel pathways for reoxidation of cytosolic and intramitochondrial NADH. The major challenge that lies ahead is to elucidate the physiological function of parallel pathways for NADH oxidation in wild-type cells, both under steady-state and transient-state conditions. This requires the development of techniques for accurate measurement of intracellular metabolite concentrations in separate metabolic compartments. PMID:11152939

Bakker, B M; Overkamp, K M; van Maris AJ; Ktter, P; Luttik, M A; van Dijken JP; Pronk, J T

2001-01-01

155

Response of Saccharomyces cerevisiae to Heavy Element Stress: Lead vs. Uranium  

Microsoft Academic Search

We have examined the responses of Saccharomyces cerevisiae in media containing Pb ions and compared it to those in media containing UO 2 ions to elucidate the stress effects of heavy elements. Cultivation of S. cerevisiae in a medium containing 1.0 10 M Pb showed nearly the same growth as that in the control medium while growth was inhibited

Fuminori Sakamoto; Toshihiko Ohnuki; T. Fujii; Haruyuki Iefuji

2010-01-01

156

Fermentation behaviour of controlled mixed and sequential cultures of Candida cantarellii and Saccharomyces cerevisiae wine yeasts  

Microsoft Academic Search

Behaviour of Candida cantarellii and Saccharomyces cerevisiae strains during the fermentation of Syrah grape must using pure, mixed and sequential yeast cultures was studied. Different\\u000a kinds of inocula have been tested according to the type of culture. Inocula proportions used in mixed C. cantarellii and S. cerevisiae strains reflect the population levels in natural grape microbiota. Biomass evolution of both

M. E. Toro; F. Vazquez

2002-01-01

157

Homology of Saccharomyces cerevisiae ADH4 to an iron-activated alcohol dehydrogenase from Zymomonas mobilis  

Microsoft Academic Search

Insertion of the transposable element Ty at the ADH4 locus results in increased levels of a new alcohol dehydrogenase (ADH) activity in Saccharomyces cerevisiae. The DNA sequence of this locus has been determined. It contains a long open reading frame which is not homologous to the other ADH isozymes that have been characterized in S. cerevisiae nor does it show

Valerie M. Williamson; Charlotte E. Paquin

1987-01-01

158

Properties of Natural Double-Strand-Break Sites at a Recombination Hotspot in Saccharomyces cerevisiae  

Microsoft Academic Search

This study addresses three questions about the properties of recombination hotspots in Saccharomyces cerevisiae : How much DNA is required for double-strand-break (DSB) site recognition? Do naturally oc- curring DSB sites compete with each other in meiotic recombination? What role does the sequence located at the sites of DSBs play? In S. cerevisiae, the HIS2 meiotic recombination hotspot displays a

Stuart J. Haring; George R. Halley; Alex J. Jones; Robert E. Malone

2003-01-01

159

Control of Saccharomyces cerevisiae Filamentous Growth by Cyclin-Dependent Kinase Cdc28  

Microsoft Academic Search

The ascomycete Saccharomyces cerevisiae exhibits alternative vegetative growth states referred to as the yeast form and the filamentous form, and it switches between the two morphologies depending on specific environ- mental signals. To identify molecules involved in control of morphologic differentiation, this study character- ized mutant S. cerevisiae strains that exhibit filamentous growth in the absence of the normal external

NICHOLAS P. EDGINGTON; MELISSA J. BLACKETER; TRACIE A. BIERWAGEN; ALAN M. MYERS

1999-01-01

160

Identification and Characterization of Antifungal Compounds Using a Saccharomyces cerevisiae Reporter Bioassay  

Microsoft Academic Search

New antifungal drugs are urgently needed due to the currently limited selection, the emergence of drug resistance, and the toxicity of several commonly used drugs. To identify drug leads, we screened small molecules using a Saccharomyces cerevisiae reporter bioassay in which S. cerevisiae heterologously expresses Hik1, a group III hybrid histidine kinase (HHK) from Magnaporthe grisea. Group III HHKs are

Brad Tebbets; Douglas Stewart; Stephanie Lawry; Jeniel Nett; Andre Nantel; David Andes; Bruce S. Klein

2012-01-01

161

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

PubMed Central

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

Wang, Shi-An

2013-01-01

162

Metabolic Engineering of Saccharomyces cerevisiae to Minimize the Production of Ethyl Carbamate in Wine  

Microsoft Academic Search

Saccharomyces cerevisiae metabolizes arginine, one of the major amino acids in grape musts, to orni- thine and urea during wine fermentations. Wine yeast strains of S. cerevisiae do not fully metabolize urea during grape must fermentation. Urea is secreted by yeast cells and it reacts spontaneously with ethanol in wine to form ethyl carbamate, a potential carcinogenic agent for humans.

Joana Coulon; John I. Husnik; Debra L. Inglis; George K. van der Merwe; Aline Lonvaud; Daniel J. Erasmus; Hennie J. J. van Vuuren

163

Prezygotic isolation between Saccharomyces cerevisiae and Saccharomyces paradoxus through differences in mating speed and germination timing.  

PubMed

Although prezygotic isolation between sympatric populations of closely related animal and plant species is well documented, far less is known about such evolutionary phenomena in sexual microbial species, as most are difficult to culture and manipulate. Using the molecular and genetic tools available for the unicellular fungus Saccharomyces cerevisiae, and applying them to S. paradoxus, we tested the behavior of individual cells from sympatric woodland populations of both species for evidence of prezygotic isolation. First, we confirmed previous observations that vegetative cells of both species mate preferentially with S. cerevisiae. Next, we found evidence for mate discrimination in spores, the stage in which outcrossing opportunities are most likely to occur. There were significant differences in germination timing between the species: under the same conditions, S. paradoxus spores do not begin germinating until almost all S. cerevisiae spores have finished. When germination time was staggered, neither species discriminated against the other, suggesting that germination timing is responsible for the observed mate discrimination. Our results indicate that the mechanisms of allochronic isolation that are well known in plants and animals can also operate in sexual microbes. PMID:22486698

Murphy, Helen A; Zeyl, Clifford W

2012-04-01

164

[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 releive 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 eventhough 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, Glden; Kantarci, Glin

2014-04-01

165

Improved galactose fermentation of Saccharomyces cerevisiae through inverse metabolic engineering.  

PubMed

Although Saccharomyces cerevisiae is capable of fermenting galactose into ethanol, ethanol yield and productivity from galactose are significantly lower than those from glucose. An inverse metabolic engineering approach was undertaken to improve ethanol yield and productivity from galactose in S. cerevisiae. A genome-wide perturbation library was introduced into S. cerevisiae, and then fast galactose-fermenting transformants were screened using three different enrichment methods. The characterization of genetic perturbations in the isolated transformants revealed three target genes whose overexpression elicited enhanced galactose utilization. One confirmatory (SEC53 coding for phosphomannomutase) and two novel targets (SNR84 coding for a small nuclear RNA and a truncated form of TUP1 coding for a general repressor of transcription) were identified as overexpression targets that potentially improve galactose fermentation. Beneficial effects of overexpression of SEC53 may be similar to the mechanisms exerted by overexpression of PGM2 coding for phosphoglucomutase. While the mechanism is largely unknown, overexpression of SNR84, improved both growth and ethanol production from galactose. The most remarkable improvement of galactose fermentation was achieved by overexpression of the truncated TUP1 (tTUP1) gene, resulting in unrivalled galactose fermentation capability, that is 250% higher in both galactose consumption rate and ethanol productivity compared to the control strain. Moreover, the overexpression of tTUP1 significantly shortened lag periods that occurs when substrate is changed from glucose to galactose. Based on these results we proposed a hypothesis that the mutant Tup1 without C-terminal repression domain might bring in earlier and higher expression of GAL genes through partial alleviation of glucose repression. mRNA levels of GAL genes (GAL1, GAL4, and GAL80) indeed increased upon overexpression of tTUP. The results presented in this study illustrate that alteration of global regulatory networks through overexpression of the identified targets (SNR84 and tTUP1) is as effective as overexpression of a rate limiting metabolic gene (PGM2) in the galactose assimilation pathway for efficient galactose fermentation in S. cerevisiae. In addition, these results will be industrially useful in the biofuels area as galactose is one of the abundant sugars in marine plant biomass such as red seaweed as well as cheese whey and molasses. PMID:21246509

Lee, Ki-Sung; Hong, Min-Eui; Jung, Suk-Chae; Ha, Suk-Jin; Yu, Byung Jo; Koo, Hyun Min; Park, Sung Min; Seo, Jin-Ho; Kweon, Dae-Hyuk; Park, Jae Chan; Jin, Yong-Su

2011-03-01

166

Engineering the Monomer Composition of Polyhydroxyalkanoates Synthesized in Saccharomyces cerevisiae  

PubMed Central

Polyhydroxyalkanoates (PHAs) have received considerable interest as renewable-resource-based, biodegradable, and biocompatible plastics with a wide range of potential applications. We have engineered the synthesis of PHA polymers composed of monomers ranging from 4 to 14 carbon atoms in either the cytosol or the peroxisome of Saccharomyces cerevisiae by harnessing intermediates of fatty acid metabolism. Cytosolic PHA production was supported by establishing in the cytosol critical ?-oxidation chemistries which are found natively in peroxisomes. This platform was utilized to supply medium-chain (C6 to C14) PHA precursors from both fatty acid degradation and synthesis to a cytosolically expressed medium-chain-length (mcl) polymerase from Pseudomonas oleovorans. Synthesis of short-chain-length PHAs (scl-PHAs) was established in the peroxisome of a wild-type yeast strain by targeting the Ralstonia eutropha scl polymerase to the peroxisome. This strain, harboring a peroxisomally targeted scl-PHA synthase, accumulated PHA up to approximately 7% of its cell dry weight. These results indicate (i) that S. cerevisiae expressing a cytosolic mcl-PHA polymerase or a peroxisomal scl-PHA synthase can use the 3-hydroxyacyl coenzyme A intermediates from fatty acid metabolism to synthesize PHAs and (ii) that fatty acid degradation is also possible in the cytosol as ?-oxidation might not be confined only to the peroxisomes. Polymers of even-numbered, odd-numbered, or a combination of even- and odd-numbered monomers can be controlled by feeding the appropriate substrates. This ability should permit the rational design and synthesis of polymers with desired material properties.

Zhang, Bo; Carlson, Ross; Srienc, Friedrich

2006-01-01

167

Genetic and regulatory aspects of methionine biosynthesis in Saccharomyces cerevisiae.  

PubMed

Methionine biosynthesis and regulation of four enzymatic steps involved in this pathway were studied in Saccharomyces cerevisiae, in relation to genes concerned with resistance to ethionine (eth(1) and eth(2)). Data presented in this paper and others favor a scheme which excludes cystathionine as an obligatory intermediate. Kinetic data are presented for homocysteine synthetase [K(m)(O-acetyl-l-homoserine) = 7 x 10(-3)m; K(i) (l-methionine) = 1.9 x 10(-3)m]. Enzymes catalyzing steps 3, 4, 5, and 9 were repressible by methionine. Enzyme 4 (homoserine-O-transacetylase) and enzyme 9 (homocysteine synthetase) were simultaneously derepressed in strains carrying the mutant allele eth(2) (r). Studies on diploid strains confirmed the dominance of the eth(2) (s) allele over eth(2) (r). Regulation of enzyme 3 (homoserine dehydrogenase) and enzyme 5 (adenosine triphosphate sulfurylase) is not modified by the allele eth(2) (r). The other gene eth(1) did not appear to participate in regulation of these four steps. Gene enzyme relationship was determined for three of the four steps studied (steps 3, 4, and 9). The structural genes concerned with the steps which are under the control of eth(2) (met(8): enzyme 9 and met(a): enzyme 4) segregate independently, and are unlinked to eth(2). These results are compatible with the idea that the gene eth(2) is responsible for the synthesis of a pleiotropic methionine repressor and suggest the existence of at least two different methionine repressors in S. cerevisiae. Implications of these findings in general regulatory mechanisms have been discussed. PMID:5764336

Cherest, H; Eichler, F; Robichon-Szulmajster, H

1969-01-01

168

Antifungal activity in Saccharomyces cerevisiae is modulated by calcium signalling.  

PubMed

The most important group of antifungals is the azoles (e.g. miconazole), which act by inhibiting lanosterol demethylase in the sterol biosynthesis pathway. Azole activity can be modulated through structural changes in lanosterol demethylase, altered expression of its gene ERG11, alterations in other sterol biosynthesis enzymes or altered expression of multidrug transporters. We present evidence that azole activity versus Saccharomyces cerevisiae is also modulated by Ca2+-regulated signalling. (i) Azole activity was reduced by the addition of Ca2+. Conversely, azole activity was enhanced by the addition of Ca2+ chelator EGTA. (ii) Three structurally distinct inhibitors (fluphenazine, calmidazolium and a W-7 analogue) of the Ca2+-binding regulatory protein calmodulin enhanced azole activity. (iii) Two structurally distinct inhibitors (cyclosporin and FK506) of the Ca2+-calmodulin-regulated phosphatase calcineurin enhanced azole activity. (iv) Strains in which the Ca2+ binding sites of calmodulin were eliminated and strains in which the calcineurin subunit genes were disrupted demonstrated enhanced azole sensitivity; conversely, a mutant with constitutively activated calcineurin phosphatase demonstrated decreased azole sensitivity. (v) CRZ1/TCN1 encodes a transcription factor regulated by calcineurin phosphatase; its disruption enhanced azole sensitivity, whereas its overexpression decreased azole sensitivity. All the above treatments had comparable effects on the activity of terbinafine, an inhibitor of squalene epoxidase within the sterol biosynthesis pathway, but had little or no effect on the activity of drugs with unrelated targets. (vi) Treatment of S. cerevisiae with azole or terbinafine resulted in transcriptional upregulation of genes FKS2 and PMR1 known to be Ca2+ regulated. A model to explain the role of Ca2+-regulated signalling in azole/terbinafine tolerance is proposed. PMID:12366848

Edlind, Thomas; Smith, Lamar; Henry, Karl; Katiyar, Santosh; Nickels, Joseph

2002-10-01

169

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.

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

1995-01-01

170

Genetic and Regulatory Aspects of Methionine Biosynthesis in Saccharomyces cerevisiae  

PubMed Central

Methionine biosynthesis and regulation of four enzymatic steps involved in this pathway were studied in Saccharomyces cerevisiae, in relation to genes concerned with resistance to ethionine (eth1 and eth2). Data presented in this paper and others favor a scheme which excludes cystathionine as an obligatory intermediate. Kinetic data are presented for homocysteine synthetase [Km(O-acetyl-l-homoserine) = 7 10?3m; Ki (l-methionine) = 1.9 10?3m]. Enzymes catalyzing steps 3, 4, 5, and 9 were repressible by methionine. Enzyme 4 (homoserine-O-transacetylase) and enzyme 9 (homocysteine synthetase) were simultaneously derepressed in strains carrying the mutant allele eth2r. Studies on diploid strains confirmed the dominance of the eth2s allele over eth2r. Regulation of enzyme 3 (homoserine dehydrogenase) and enzyme 5 (adenosine triphosphate sulfurylase) is not modified by the allele eth2r. The other gene eth1 did not appear to participate in regulation of these four steps. Gene enzyme relationship was determined for three of the four steps studied (steps 3, 4, and 9). The structural genes concerned with the steps which are under the control of eth2 (met8: enzyme 9 and meta: enzyme 4) segregate independently, and are unlinked to eth2. These results are compatible with the idea that the gene eth2 is responsible for the synthesis of a pleiotropic methionine repressor and suggest the existence of at least two different methionine repressors in S. cerevisiae. Implications of these findings in general regulatory mechanisms have been discussed. Images

Cherest, H.; Eichler, F.; de Robichon-Szulmajster, H.

1969-01-01

171

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.

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

1996-01-01

172

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.

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

2003-01-01

173

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

174

V-ATPase dysfunction suppresses polyphosphate synthesis in Saccharomyces cerevisiae.  

PubMed

The yeast Saccharomyces cerevisiae accumulates the high levels of inorganic polyphosphates (polyPs) performing in the cells numerous functions, including phosphate and energy storage. The effects of vacuolar membrane ATPase (V-ATPase) dysfunction were studied on polyP accumulation under short-term cultivation in the Pi-excess media after Pi starvation. The addition of bafilomycin A1, a specific inhibitor of V-ATPase, to the medium with glucose resulted in strong inhibition of the synthesis of long-chain polyP and in substantial suppression of short-chain polyP. The addition of bafilomycin to the medium with ethanol resulted in decreased accumulation of high-molecular polyP, while the accumulation of low-molecular polyP was not affected. The levels of polyP synthesis in the mutant strain with a deletion in the vma2 gene encoding a V-ATPase subunit were significantly lower than in the parent strain in the media with glucose and with ethanol. The synthesis of the longest chain polyP was not observed in the mutant cells. The synthesis of only the low-polymer acid-soluble polyP fraction occurred in the cells of the mutant strain. However, the level of polyP1 was nearly tenfold lower than compared to the cells of the parent strain. Both bafilomycin A1 and the mutation in vacuolar ATPase subunit vma2 lead to a considerable decrease of cellular polyP accumulation. Thus, the defects in ??H(+) formation on the vacuolar membrane resulted in the decrease of polyP biosynthesis in S. cerevisiae. PMID:23371743

Trilisenko, Ludmila; Tomashevsky, Alexander; Kulakovskaya, Tatiana; Kulaev, Igor

2013-11-01

175

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

PubMed Central

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.

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

2013-01-01

176

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

177

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

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

1994-01-01

178

Defects arising from whole-genome duplications in Saccharomyces cerevisiae.  

PubMed Central

Comparisons among closely related species have led to the proposal that the duplications found in many extant genomes are the remnants of an ancient polyploidization event, rather than a result of successive duplications of individual chromosomal segments. If this interpretation is correct, it would support Ohno's proposal that polyploidization drives evolution by generating the genetic material necessary for the creation of new genes. Paradoxically, analysis of contemporary polyploids suggests that increased ploidy is an inherently unstable state. To shed light on this apparent contradiction and to determine the effects of nascent duplications of the entire genome, we generated isogenic polyploid strains of the budding yeast Saccharomyces cerevisiae. Our data show that an increase in ploidy results in a marked decrease in a cell's ability to survive during stationary phase in growth medium. Tetraploid cells die rapidly, whereas isogenic haploids remain viable for weeks. Unlike haploid cells, which arrest growth as unbudded cells, tetraploid cells continue to bud and form mitotic spindles in stationary phase. The stationary-phase death of tetraploids can be prevented by mutations or conditions that result in growth arrest. These data show that whole-genome duplications are accompanied by defects that affect viability and subsequent survival of the new organism.

Andalis, Alex A; Storchova, Zuzana; Styles, Cora; Galitski, Timothy; Pellman, David; Fink, Gerald R

2004-01-01

179

Reversal of PCNA ubiquitylation by Ubp10 in Saccharomyces cerevisiae.  

PubMed

Regulation of PCNA ubiquitylation plays a key role in the tolerance to DNA damage in eukaryotes. Although the evolutionary conserved mechanism of PCNA ubiquitylation is well understood, the deubiquitylation of ubPCNA remains poorly characterized. Here, we show that the histone H2B(K123) ubiquitin protease Ubp10 also deubiquitylates ubPCNA in Saccharomyces cerevisiae. Our results sustain that Ubp10-dependent deubiquitylation of the sliding clamp PCNA normally takes place during S phase, likely 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-Snchez, Alfonso; Andrs, Sonia; Conde, Francisco; San-Segundo, Pedro A; Bueno, Avelino

2012-01-01

180

Genotoxicity assessment of amaranth and allura red using Saccharomyces cerevisiae.  

PubMed

Amaranth (E123) and Allura red (E129), very important food azo dyes used in food, drug, paper, cosmetic and textile industries, were assessed for their genotoxic potential through comet assay in yeast cells. Comet assay was standardized by with different concentration of H(2)O(2). Concentrations of Amaranth and Allura red were maintained in sorbitol buffer starting from 9.76to 5,000?g/mL and 1נ10(4) cells were incubated at two different incubation temperatures 28 and 37C. Amaranth (E123) and Allura red (E129) were found to exhibit their genotoxic effect directly in Saccharomyces cerevisiae. No significant genotoxic activity was observed for Amaranth and Allura red at 28C but at 37C direct relation of Amaranth concentration with comet tail was significant and no positive relation was seen with time exposure factor. At 37C the minimum concentration of Amaranth and Allura red at which significant DNA damage observed through comet assay was 1,250?g/mL in 2nd h post exposure time. The results indicated that food colors should be carefully used in baking products as heavy concentration of food colors could affect the fermentation process of baking. PMID:23132362

Jabeen, Hafiza Sumara; ur Rahman, Sajjad; Mahmood, Shahid; Anwer, Sadaf

2013-01-01

181

Genome engineering in Saccharomyces cerevisiae using CRISPR-Cas systems  

PubMed Central

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) systems in bacteria and archaea use RNA-guided nuclease activity to provide adaptive immunity against invading foreign nucleic acids. Here, we report the use of type II bacterial CRISPR-Cas system in Saccharomyces cerevisiae for genome engineering. The CRISPR-Cas components, Cas9 gene and a designer genome targeting CRISPR guide RNA (gRNA), show robust and specific RNA-guided endonuclease activity at targeted endogenous genomic loci in yeast. Using constitutive Cas9 expression and a transient gRNA cassette, we show that targeted double-strand breaks can increase homologous recombination rates of single- and double-stranded oligonucleotide donors by 5-fold and 130-fold, respectively. In addition, co-transformation of a gRNA plasmid and a donor DNA in cells constitutively expressing Cas9 resulted in near 100% donor DNA recombination frequency. Our approach provides foundations for a simple and powerful genome engineering tool for site-specific mutagenesis and allelic replacement in yeast.

DiCarlo, James E.; Norville, Julie E.; Mali, Prashant; Rios, Xavier; Aach, John; Church, George M.

2013-01-01

182

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.

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

2014-01-01

183

Oxygen requirements of yeasts. [Saccharomyces cerevisiae; Candida tropicalis  

SciTech Connect

Type species of 75 yeast genera were examined for their ability to grow anaerobically in complex and mineral media. To define anaerobic conditions, we added a redox indicator, resazurin, to the media to determine low redox potentials. All strains tested were capable of fermenting glucose to ethanol in oxygen-limited shake-flask cultures, even those of species generally regarded as nonfermentative. However, only 23% of the yeast species tested grew under anaerobic conditions. A comparative study with a number of selected strains revealed that Saccharomyces cerevisiae stands out as a yeast capable of rapid growth at low redox potentials. Other yeasts, such as Torulaspora delbrueckii and Candida tropicalis, grew poorly ({mu}{sub max}, 0.03 and 0.05 h{sup {minus}1}, respectively) under anaerobic conditions in mineral medium supplemented with Tween 80 and ergosterol. The latter organisms grew rapidly under oxygen limitation and then displayed a high rate of alcoholic fermentation. It can be concluded that these yeasts have hitherto-unidentified oxygen requirements for growth.

Visser, W.; Scheffers, W.A.; Batenburg-Van Der Vegte, W.H.; Van Dijken, J.P. (Delft Univ. of Technology (Netherlands))

1990-12-01

184

Small molecule activators of sirtuins extend Saccharomyces cerevisiae lifespan.  

PubMed

In diverse organisms, calorie restriction slows the pace of ageing and increases maximum lifespan. In the budding yeast Saccharomyces cerevisiae, calorie restriction extends lifespan by increasing the activity of Sir2 (ref. 1), a member of the conserved sirtuin family of NAD(+)-dependent protein deacetylases. Included in this family are SIR-2.1, a Caenorhabditis elegans enzyme that regulates lifespan, and SIRT1, a human deacetylase that promotes cell survival by negatively regulating the p53 tumour suppressor. Here we report the discovery of three classes of small molecules that activate sirtuins. We show that the potent activator resveratrol, a polyphenol found in red wine, lowers the Michaelis constant of SIRT1 for both the acetylated substrate and NAD(+), and increases cell survival by stimulating SIRT1-dependent deacetylation of p53. In yeast, resveratrol mimics calorie restriction by stimulating Sir2, increasing DNA stability and extending lifespan by 70%. We discuss possible evolutionary origins of this phenomenon and suggest new lines of research into the therapeutic use of sirtuin activators. PMID:12939617

Howitz, Konrad T; Bitterman, Kevin J; Cohen, Haim Y; Lamming, Dudley W; Lavu, Siva; Wood, Jason G; Zipkin, Robert E; Chung, Phuong; Kisielewski, Anne; Zhang, Li-Li; Scherer, Brandy; Sinclair, David A

2003-09-11

185

Existence of a tightly regulated water channel in Saccharomyces cerevisiae.  

PubMed

The Saccharomyces cerevisiae strain Sigma1278b possesses two putative aquaporins, Aqy1-1p and Aqy2-1p. Previous work demonstrated that Aqy1-1p functions as a water channel in Xenopus oocyte. However, no function could be attributed to Aqy2-1p in this system. Specific antibodies were used to follow the expression of Aqy1-1p and Aqy2-1p in the yeast. Aqy1-1p was never detected whatever the growth phase and culture conditions tested. In contrast, Aqy2-1p was detected only during the exponential growth phase in rich medium containing glucose. Aqy2-1p expression was repressed by hyper-osmotic culture conditions. Both immunocytochemistry and biochemical subcellular fractionation demonstrated that Aqy2-1p is located on the endoplasmic reticulum (ER) as well as on the plasma membrane. In microsomal vesicles enriched in ER, a water channel activity due to Aqy2-1p was detected by stopped-flow analysis. Our results show that the expression of aquaporins is tightly controlled. The physiological relevance of aquaporin-mediated water transport in yeast is discussed. PMID:11168368

Meyrial, V; Laiz, V; Gobin, R; Ripoche, P; Hohmann, S; Tacnet, F

2001-01-01

186

TOR and RAS pathways regulate desiccation tolerance in Saccharomyces cerevisiae.  

PubMed

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

187

Cellular Memory of Acquired Stress Resistance in Saccharomyces cerevisiae  

PubMed Central

Cellular memory of past experiences has been observed in several organisms and across a variety of experiences, including bacteria remembering prior nutritional status and amoeba learning to anticipate future environmental conditions. Here, we show that Saccharomyces cerevisiae maintains a multifaceted memory of prior stress exposure. We previously demonstrated that yeast cells exposed to a mild dose of salt acquire subsequent tolerance to severe doses of H2O2. We set out to characterize the retention of acquired tolerance and in the process uncovered two distinct aspects of cellular memory. First, we found that H2O2 resistance persisted for four to five generations after cells were removed from the prior salt treatment and was transmitted to daughter cells that never directly experienced the pretreatment. Maintenance of this memory did not require nascent protein synthesis after the initial salt pretreatment, but rather required long-lived cytosolic catalase Ctt1p that was synthesized during salt exposure and then distributed to daughter cells during subsequent cell divisions. In addition to and separable from the memory of H2O2 resistance, these cells also displayed a faster gene-expression response to subsequent stress at >1000 genes, representing transcriptional memory. The faster gene-expression response requires the nuclear pore component Nup42p and serves an important function by facilitating faster reacquisition of H2O2 tolerance after a second cycle of salt exposure. Memory of prior stress exposure likely provides a significant advantage to microbial populations living in ever-changing environments.

Guan, Qiaoning; Haroon, Suraiya; Bravo, Diego Gonzalez; Will, Jessica L.; Gasch, Audrey P.

2012-01-01

188

Global optimization of the saccharomyces cerevisiae. Fermentation process.  

PubMed

In this paper steady-state optimization of the Saccharomyces cerevisiae fermentation process problem is performed revealing the existence of multiple optimum solutions. The globally optimum solution was determined using the NEOS global optimization solver LINDO. A branch and bound strategy (bnb20.m) and the global search and multistart algorithms in the MATLAB global optimization toolbox were successful in determining locally optimum solutions and these results are validated by plotting the objective function against the decision variables. While in some cases all the strategies were successful in obtaining the globally optimum solutions, an example is presented where the most beneficial product value, which is not a stationary point and lies on the feasible boundary, is obtained by the LINDO global optimization solver (but not the other routines) as the globally optimum solution. The Jones-Kompala model was used to model the steady-state of the fermentation process. While several articles have been published demonstrating the existence of nonlinearities and bifurcations in this model, the challenges posed by this model to optimization has never been investigated so far and this work attempts to do so. Both dilution rate and the oxygen mass transfer coefficient were used as the decision variables individually and together. 2013 American Institute of Chemical Engineers Biotechnol. Prog., 2013. PMID:23737357

Sridhar, Lakshmi N

2013-06-01

189

Global optimization of the Saccharomyces cerevisiae: fermentation process.  

PubMed

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

Sridhar, Lakshmi N

2013-01-01

190

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.

Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie

2013-01-01

191

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

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

1995-01-01

192

An overview of membrane transport proteins in Saccharomyces cerevisiae.  

PubMed

All eukaryotic cells contain a wide variety of proteins embedded in the plasma and internal membranes, which ensure transmembrane solute transport. It is now established that a large proportion of these transport proteins can be grouped into families apparently conserved throughout organisms. This article presents the data of an in silicio analysis aimed at establishing a preliminary classification of membrane transport proteins in Saccharomyces cerevisiae. This analysis was conducted at a time when about 65% of all yeast genes were available in public databases. In addition to approximately 60 transport proteins whose function was at least partially known, approximately 100 deduced protein sequences of unknown function display significant sequence similarity to membrane transport proteins characterized in yeast and/or other organisms. While some protein families have been well characterized by classical genetic experimental approaches, others have largely if not totally escaped characterization. The proteins revealed by this in silicio analysis also include a putative K+ channel, proteins similar to aquaporins of plant and animal origin, proteins similar to Na+-solute symporters, a protein very similar to electroneural cation-chloride cotransporters, and a putative Na+-H+ antiporter. A new research area is anticipated: the functional analysis of many transport proteins whose existence was revealed by genome sequencing. PMID:8720066

Andre, B

1995-12-01

193

Proteomic Profiling of Autophagosome Cargo in Saccharomyces cerevisiae  

PubMed Central

Macroautophagy (autophagy) is a bulk protein-degradation system ubiquitously conserved in eukaryotic cells. During autophagy, cytoplasmic components are enclosed in a membrane compartment, called an autophagosome. The autophagosome fuses with the vacuole/lysosome and is degraded together with its cargo. Because autophagy is important for the maintenance of cellular homeostasis by degrading unwanted proteins and organelles, identification of autophagosome cargo proteins (i.e., the targets of autophagy) will aid in understanding the physiological roles of autophagy. In this study, we developed a method for monitoring intact autophagosomes ex vivo by detecting the fluorescence of GFP-fused aminopeptidase I, the best-characterized selective cargo of autophagosomes in Saccharomyces cerevisiae. This method facilitated optimization of a biochemical procedure to fractionate autophagosomes. A combination of LC-MS/MS with subsequent statistical analyses revealed a list of autophagosome cargo proteins; some of these are selectively enclosed in autophagosomes and delivered to the vacuole in an Atg11-independent manner. The methods we describe will be useful for analyzing the mechanisms and physiological significance of Atg11-independent selective autophagy.

Morimoto, Mayumi; Fujii, Kiyonaga; Noda, Nobuo N.; Inagaki, Fuyuhiko; Ohsumi, Yoshinori

2014-01-01

194

Identification of RNA recognition elements in the Saccharomyces cerevisiae transcriptome  

PubMed Central

Post-transcriptional regulation of gene expression, including mRNA localization, translation and decay, is ubiquitous yet still largely unexplored. How is the post-transcriptional regulatory program of each mRNA encoded in its sequence? Hundreds of specific RNA-binding proteins (RBPs) appear to play roles in mediating the post-transcriptional regulatory program, akin to the roles of specific DNA-binding proteins in transcription. As a step toward decoding the regulatory programs encoded in each mRNA, we focused on specific mRNAprotein interactions. We computationally analyzed the sequences of Saccharomyces cerevisiae mRNAs bound in vivo by 29 specific RBPs, identifying eight novel candidate motifs and confirming or extending six earlier reported recognition elements. Biochemical selections for RNA sequences selectively recognized by 12 yeast RBPs yielded novel motifs bound by Pin4, Nsr1, Hrb1, Gbp2, Sgn1 and Mrn1, and recovered the known recognition elements for Puf3, She2, Vts1 and Whi3. Most of the RNA elements we uncovered were associated with coherent mRNA expression changes and were significantly conserved in related yeasts, supporting their functional importance and suggesting that the corresponding RNAprotein interactions are evolutionarily conserved.

Riordan, Daniel P.; Herschlag, Daniel; Brown, Patrick O.

2011-01-01

195

Misacylation of tRNA with methionine in Saccharomyces cerevisiae  

PubMed Central

Accurate transfer RNA (tRNA) aminoacylation by aminoacyl-tRNA synthetases controls translational fidelity. Although tRNA synthetases are generally highly accurate, recent results show that the methionyl-tRNA synthetase (MetRS) is an exception. MetRS readily misacylates non-methionyl tRNAs at frequencies of up to 10% in mammalian cells; such mismethionylation may serve a beneficial role for cells to protect their own proteins against oxidative damage. The Escherichia coli MetRS mismethionylates two E. coli tRNA species in vitro, and these two tRNAs contain identity elements for mismethionylation. Here we investigate tRNA mismethionylation in Saccharomyces cerevisiae. tRNA mismethionylation occurs at a similar extent in vivo as in mammalian cells. Both cognate and mismethionylated tRNAs have similar turnover kinetics upon cycloheximide treatment. We identify specific arginine/lysine to methionine-substituted peptides in proteomic mass spectrometry, indicating that mismethionylated tRNAs are used in translation. The yeast MetRS is part of a complex containing the anchoring protein Arc1p and the glutamyl-tRNA synthetase (GluRS). The recombinant Arc1pMetRSGluRS complex binds and mismethionylates many tRNA species in vitro. Our results indicate that the yeast MetRS is responsible for extensive misacylation of non-methionyl tRNAs, and mismethionylation also occurs in this evolutionary branch.

Wiltrout, Elizabeth; Goodenbour, Jeffrey M.; Frechin, Mathieu; Pan, Tao

2012-01-01

196

MAP Kinase Pathways in the Yeast Saccharomyces cerevisiae  

PubMed Central

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, Michael C.; Albertyn, Jacobus; Alexander, Matthew; Davenport, Kenneth

1998-01-01

197

Biotransformation of mogrosides from Siraitia grosvenorii Swingle by Saccharomyces cerevisiae.  

PubMed

Mogrosides are a group of triterpenoidal saponins from the fruit of Siraitia grosvenorii Swingle; they are intensely sweet and have consequently been used as a substitute for sugar by the food industry. The lack of efficient methods to produce specific mogrosides has hindered investigation of the relationship between their structure and bioactivity, e.g., down-regulation of blood glucose levels, anti-inflammation, and antiviral infection. Here, we attempt to selectively convert the major saponin mogroside V, a mogrol pentaglucoside, into mogroside III E, a triglucoside, via the ?-glucosidases of the budding yeast Saccharomyces cerevisiae. We report that the ?-glucopyranosyl and ?-glucopyranosyl-(1?2)-?-d-glucopyranosyl attached on C-3 and -24 of mogrol, respectively, were resistant to hydrolysis by yeast ?-d-glucosidases. We further screened 16 mutants bearing single defective glucanase or glucosidase genes, thereby demonstrating that Exg1 is a major enzyme of the initiation of mogroside V conversion. Deletion of the KRE6 gene unexpectedly facilitated the production of mogroside III E in yeast culture. This paper demonstrates that yeast knockout mutants are a valuable tool for saponin modification and for studying the specificity of glucosidase function. PMID:23796186

Chiu, Chun-Hui; Wang, Reuben; Lee, Cho-Ching; Lo, Yi-Chen; Lu, Ting-Jang

2013-07-24

198

Lipid droplet autophagy in the yeast Saccharomyces cerevisiae  

PubMed Central

Cytosolic lipid droplets (LDs) are ubiquitous organelles in prokaryotes and eukaryotes that play a key role in cellular and organismal lipid homeostasis. Triacylglycerols (TAGs) and steryl esters, which are stored in LDs, are typically mobilized in growing cells or upon hormonal stimulation by LD-associated lipases and steryl ester hydrolases. Here we show that in the yeast Saccharomyces cerevisiae, LDs can also be turned over in vacuoles/lysosomes by a process that morphologically resembles microautophagy. A distinct set of proteins involved in LD autophagy is identified, which includes the core autophagic machinery but not Atg11 or Atg20. Thus LD autophagy is distinct from endoplasmic reticulumautophagy, pexophagy, or mitophagy, despite the close association between these organelles. Atg15 is responsible for TAG breakdown in vacuoles and is required to support growth when de novo fatty acid synthesis is compromised. Furthermore, none of the core autophagy proteins, including Atg1 and Atg8, is required for LD formation in yeast.

van Zutphen, Tim; Todde, Virginia; de Boer, Rinse; Kreim, Martin; Hofbauer, Harald F.; Wolinski, Heimo; Veenhuis, Marten; van der Klei, Ida J.; Kohlwein, Sepp D.

2014-01-01

199

Biosynthesis of diphthamide in the yeast Saccharomyces cerevisiae  

SciTech Connect

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

Chen, J.Y.C.

1985-01-01

200

Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae.  

PubMed

The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth. PMID:24483210

Conrad, Michaela; Schothorst, Joep; Kankipati, Harish Nag; Van Zeebroeck, Griet; Rubio-Texeira, Marta; Thevelein, Johan M

2014-03-01

201

Osmotic shock augments ethanol stress in Saccharomyces cerevisiae MTCC 2918.  

PubMed

Yeast cells sense and respond to hypertonicity. Saccharomyces cerevisiae MTCC 2918 was tested for its metabolic status in 1M NaCl by cell viability analysis, intracellular glycerol content and total antioxidant capacity. Yeast cell viability was maximum in 1M NaCl and 24h addition of 1M NaCl was effective in induction of hyperosmolarity. Increased glycerol contents in cells treated with salt indicated adaptation to osmotic stress with a maximum of 240.870.38mg/g dry weight (DW) at 72h. The total antioxidant status with 1M NaCl was 9.290.39mM/gDW at 96h reflecting free radical quenching to overcome stress with increasing growth period. Considering that pre-adaptation to one type of stress evoked a protective response to other stress factors, we have attempted the cross adaptation of osmotic shock to high ethanol concentrations. In effect, we observed that osmotic shock lowered the cell survival by augmentation of cell toxicity by ethanol due to stress induction during exponential phase. Glycerol accumulation to an order of 470.270.53mg/g DW at 48h in 1M NaCl and 12% ethanol indicated that both stresses culminated in membrane disruption further leading to cell burst and contributed to the stress overload. PMID:22038037

John, Geraldine S M; Gayathiri, Murugesan; Rose, Chellan; Mandal, Asit B

2012-02-01

202

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.

Hoang, Stephen A.; Bekiranov, Stefan

2013-01-01

203

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; Penttil, Merja; Koivula, Anu

2014-04-01

204

Effects of ethanol on the temperature profile of Saccharomyces cerevisiae.  

PubMed

Ethanol at concentrations above 3% (w/v) decreased the maximum temperature for growth of Saccharomyces cerevisiae in batch culture. At 9% (w/v), the highest concentration tested, the maximum temperature suffered a decrease of about 10 degrees centigrade. At effective concentrations ethanol shifted the ARRHENIUS plots of growth and death in the superoptimal temperature range to lower temperature while an associative temperature profile was maintained. Thus at a concentration of 6% (w/v), ethanol depressed the optimum temperature for growth from 37 degree C to 25 degree C, the final maximum temperature for growth from 40 degree C to 33 degree C and the initial maximum temperature for growth from 44 degree C to 36 degree C. The results indicate that during alcoholic batch fermentation these three cardinal temperatures are variables, the values of which decrease with increasing ethanol concentration. When the ethanol concentration becomes high enough to depress them successively below the process temperature, the yeast population becomes increasingly subject to ethanol-enhanced thermal death. Implications of the findings for the production of fermentation ethanol in batch and continuous processes are discussed. PMID:7039151

van Uden, N; da Cruz Duarte, H

1981-01-01

205

Tor1 regulates protein solubility in Saccharomyces cerevisiae  

PubMed Central

Accumulation of insoluble protein in cells is associated with aging and aging-related diseases; however, the roles of insoluble protein in these processes are uncertain. The nature and impact of changes to protein solubility during normal aging are less well understood. Using quantitative mass spectrometry, we identify 480 proteins that become insoluble during postmitotic aging in Saccharomyces cerevisiae and show that this ensemble of insoluble proteins is similar to those that accumulate in aging nematodes. SDS-insoluble protein is present exclusively in a nonquiescent subpopulation of postmitotic cells, indicating an asymmetrical distribution of this protein. In addition, we show that nitrogen starvation of young cells is sufficient to cause accumulation of a similar group of insoluble proteins. Although many of the insoluble proteins identified are known to be autophagic substrates, induction of macroautophagy is not required for insoluble protein formation. However, genetic or chemical inhibition of the Tor1 kinase is sufficient to promote accumulation of insoluble protein. We conclude that target of rapamycin complex 1 regulates accumulation of insoluble proteins via mechanisms acting upstream of macroautophagy. Our data indicate that the accumulation of proteins in an SDS-insoluble state in postmitotic cells represents a novel autophagic cargo preparation process that is regulated by the Tor1 kinase.

Peters, Theodore W.; Rardin, Matthew J.; Czerwieniec, Gregg; Evani, Uday S.; Reis-Rodrigues, Pedro; Lithgow, Gordon J.; Mooney, Sean D.; Gibson, Bradford W.; Hughes, Robert E.

2012-01-01

206

HOL1 mutations confer novel ion transport in Saccharomyces cerevisiae.  

PubMed Central

Saccharomyces cerevisiae histidine auxotrophs are unable to use L-histidinol as a source of histidine even when they have a functional histidinol dehydrogenase. Mutations in the hol1 gene permit growth of His- cells on histidinol by enhancing the ability of cells to take up histidinol from the medium. Second-site mutations linked to HOL1-1 further increase histidinol uptake. HOL1 double mutants and, to a lesser extent, HOL1-1 single mutants show hypersensitivity to specific cations added to the growth medium, including Na+, Li+, Cs+, Be2+, guanidinium ion, and histidinol, but not K+, Rb+, Ca2+, or Mg2+. The Na(+)-hypersensitive phenotype is correlated with increased uptake and accumulation of this ion. The HOL1-1-101 gene was cloned and used to generate a viable haploid strain containing a hol1 deletion mutation (hol1 delta). The uptake of cations, the dominance of the mutant alleles, and the relative inability of hol1 delta cells to take up histidinol or Na+ suggest that hol1 encodes an ion transporter. The novel pattern of ion transport conferred by HOL1-1 and HOL1-1-101 mutants may be explained by reduced selectivity for the permeant ions. Images

Gaber, R F; Kielland-Brandt, M C; Fink, G R

1990-01-01

207

Cell cycle regulation of homologous recombination in Saccharomyces cerevisiae.  

PubMed

Homologous recombination (HR) contributes to maintaining genome integrity by facilitating error-free repair of DNA double-strand breaks (DSBs) primarily during the S and G2 phases of the mitotic cell cycle, while nonhomologous end joining (NHEJ) is the preferred pathway for DSB repair in G1 phase. The decision to repair a DSB by NHEJ or HR is made primarily at the level of DSB end resection, which is inhibited by the Ku complex in G1 and promoted by the Sae2 and Mre11 nucleases in S/G2 . The cell cycle regulation of HR is accomplished both at the transcription level and at the protein level through post-translational modification, degradation and subcellular localization. Cyclin-dependent kinase Cdc28 plays an established key role in these events, while the role of transcriptional regulation and protein degradation are less well understood. Here, the cell cycle regulatory mechanisms for mitotic HR in Saccharomyces cerevisiae are reviewed, and evolutionarily conserved principles are highlighted. PMID:24483249

Mathiasen, David P; Lisby, Michael

2014-03-01

208

Transcriptional Response of Saccharomyces cerevisiae to Desiccation and Rehydration  

PubMed Central

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 was compared to that of a commercially prepared dry active yeast, strikingly similar expression changes were observed. The fact that these two samples, dried by different means, possessed very similar transcriptional profiles supports the hypothesis that the response to desiccation is a coordinated event independent of the particular conditions involved in water removal. Similarities between stationary-phase-essential genes and those upregulated during desiccation were also noted, suggesting commonalities in different routes to reduced metabolic states. Trends in extracellular and intracellular glucose and trehalose levels suggested that the cells were in a holding pattern during the rehydration phase, a concept that was reinforced by cell cycle analyses. Application of a redescription mining algorithm suggested that sulfur metabolism is important for cell survival during desiccation and rehydration.

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

2005-01-01

209

Polyphosphates as an Energy Source for Growth of Saccharomyces cerevisiae.  

PubMed

Cells of the yeast Saccharomyces cerevisiae with a low content of polyphosphates (polyP) are characterized by disturbance of growth in medium with 0.5% glucose. The parent strain with polyP level reduced by phosphate starvation had a longer lag phase. The growth rate of strains with genetically determined low content of polyP due to their enhanced hydrolysis (CRN/pMB1_PPN1 Sc is a superproducer of exopolyphosphatase PPN1) or reduced synthesis (the BY4741 vma2? mutant with impaired vacuolar membrane energization) was lower in the exponential phase. The growth of cells with high content of polyP was accompanied by polyP consumption. In cells of strains with low content of polyP, CRN/pMB1_PPN1 Sc and BY4741 vma2?, their consumption was insignificant. These findings provide more evidence indicating the use of polyP as an extra energy source for maintaining high growth rate. PMID:24954599

Trilisenko, L V; Kulakovskaya, T V

2014-05-01

210

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.

Michaillat, Lydie; Mayer, Andreas

2013-01-01

211

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.

Haber, James E.

2012-01-01

212

Molecular genetics of serine and threonine catabolism in Saccharomyces cerevisiae.  

PubMed

The catabolic L-serine (L-threonine) deaminase of Saccharomyces cerevisiae allows the yeast to grow on media with L-serine or L-threonine as sole nitrogen source. A mutant, cha1 (catabolism of hydroxyamino acids), lacking this enzyme activity has been isolated. We have cloned the CHA1 gene by complementation of a cha1 mutation. Northern analysis showed that CHA1 mRNA has a size of about 1200 ribonucleotides. CHA1 is probably the structural gene for the enzyme; it is an abundant RNA in cells grown with serine and threonine as nitrogen source, whereas it is not detected when cells are grown on ammonium or proline, i.e., the transcription of the CHA1 gene is induced by serine or threonine. Under induced growth conditions haploid ilv1 CHA1 strains do not require isoleucine, i.e., the catabolic deaminase is able to substitute for the biosynthetic threnonine deaminase encoded by the ILV1 gene. We have identified a nuclear, recessive mutation, sil1, that suppresses ilv1 mutations by increased transcription of the CHA1 gene under growth conditions leading to partial induction. The sil1 mutation could exert its effect by increasing the effective pools of the hydroxyamino acids. Alternatively SIL1 may encode a negatively acting regulatory protein for CHA1. PMID:2841185

Petersen, J G; Kielland-Brandt, M C; Nilsson-Tillgren, T; Bornaes, C; Holmberg, S

1988-07-01

213

Identification and Characterization of Mutations Affecting Sporulation in Saccharomyces Cerevisiae  

PubMed Central

Mutations affecting the synthesis of the sporulation amyloglucosidase were isolated in a homothallic strain of Saccharomyces cerevisiae, SCMS7-1. Two were found, both of which were deficient in sporulation at 34. One, SL484, sporulated to 50% normal levels at 30 but less than 5% at 34 or 22. The other, SL641, failed to sporulate at any temperature. Both mutants were blocked before premeiotic DNA synthesis, and both complemented spo1, spo3, and spo7. Genetic analysis of the mutation in SL484 indicated linkage to TRP5 and placed the gene 10 map units from TRP5 on chromosome VII. A plasmid containing an insert which complements the mutation in SL484 fails to complement SL641. We therefore conclude that these two mutations are in separate genes and we propose to call these genes SPO17 and SPO18. These two genes are (with SPO7, SPO8, and SPO9) among the earliest identified in the sporulation pathway and may interact directly with the positive and negative regulators RME and IME.

Smith, L. M.; Robbins, L. G.; Kennedy, A.; Magee, P. T.

1988-01-01

214

Deglycosylation of cellulosomal enzyme enhances cellulosome assembly in Saccharomyces cerevisiae.  

PubMed

We have estimated the effects of hyper-mannosylation of dockerin-type cellulase on cellulosome assembly by using Saccharomyces cerevisiae and 44 protein glycosylation mutants, because the heterologous protein displayed on yeast is assumed to be modified by yeast-specific hyper-mannosylation. First, we constructed the yeast strain CtminiCipA, which displays a heterologous scaffolding protein (miniCipA from Clostridium thermocellum) on its cell surface, and glycosylation mutants secreting a dockerin-type cellulase (Cel8Aenz-Cel48Sdoc: a fusion protein of the catalytic domain of C. thermocellum Cel8A and the dockerin domain of C. thermocellum Cel48S). Next, minicellulosomes were assembled by mixing the CtminiCipA strain and the dockerin-type cellulase secreted by each glycosylation mutant. By using an endoglucanase assay and flow cytometric analysis, we showed that some glycosylation mutants enhanced cellulosome assembly; in particular, disruption of glycosylation genes located in the endoplasmic reticulum showed intense enhancement. These findings suggest that inhibition of the core complex or precursor formation in protein glycosylation enhances cellulosome assembly, meaning that absence of glycosylation is more important for cellulosome assembly than reducing the size of the glycochain. PMID:22154562

Suzuki, Hiroaki; Imaeda, Takao; Kitagawa, Takao; Kohda, Katsunori

2012-01-01

215

Genome engineering in Saccharomyces cerevisiae using CRISPR-Cas systems.  

PubMed

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated (Cas) systems in bacteria and archaea use RNA-guided nuclease activity to provide adaptive immunity against invading foreign nucleic acids. Here, we report the use of type II bacterial CRISPR-Cas system in Saccharomyces cerevisiae for genome engineering. The CRISPR-Cas components, Cas9 gene and a designer genome targeting CRISPR guide RNA (gRNA), show robust and specific RNA-guided endonuclease activity at targeted endogenous genomic loci in yeast. Using constitutive Cas9 expression and a transient gRNA cassette, we show that targeted double-strand breaks can increase homologous recombination rates of single- and double-stranded oligonucleotide donors by 5-fold and 130-fold, respectively. In addition, co-transformation of a gRNA plasmid and a donor DNA in cells constitutively expressing Cas9 resulted in near 100% donor DNA recombination frequency. Our approach provides foundations for a simple and powerful genome engineering tool for site-specific mutagenesis and allelic replacement in yeast. PMID:23460208

DiCarlo, James E; Norville, Julie E; Mali, Prashant; Rios, Xavier; Aach, John; Church, George M

2013-04-01

216

Regulation of repressible acid phosphatase gene transcription in Saccharomyces cerevisiae.  

PubMed Central

We examined the genetic system responsible for transcriptional regulation of repressible acid phosphatase (APase; orthophosphoric-monoester phosphohydrolase [acid optimum, EC 3.1.3.2]) in Saccharomyces cerevisiae at the molecular level by analysis of previously isolated and genetically well-defined regulatory gene mutants known to affect APase expression. These mutants identify numerous positive- (PHO4, PHO2, PHO81) and negative-acting (PHO80, PHO85) regulatory loci dispersed throughout the yeast genome. We showed that the interplay of these positive and negative regulatory genes occurs before or during APase gene transcription and that their functions are all indispensible for normal regulation of mRNA synthesis. Biochemical evidence suggests that the regulatory gene products they encode are expressed constitutively. More detailed investigation of APase synthesis is a conditional PHO80(Ts) mutant indicated that neither PHO4 nor any other protein factor necessary for APase mRNA synthesis is transcriptionally regulated by PHO80. Moreover, in the absence of PHO80, the corepressor, presumed to be a metabolite of Pi, did not inhibit their function in the transcriptional activation of APase. Images

Lemire, J M; Willcocks, T; Halvorson, H O; Bostian, K A

1985-01-01

217

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

218

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.

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

1998-01-01

219

[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

220

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; Andr, B; Urrestarazu, A

1999-05-01

221

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.

Iraqui, Ismail; Vissers, Stephan; Andre, Bruno; Urrestarazu, Antonio

1999-01-01

222

Dual effects of plant steroidal alkaloids on Saccharomyces cerevisiae.  

PubMed

Many plant species accumulate sterols and triterpenes as antimicrobial glycosides. These secondary metabolites (saponins) provide built-in chemical protection against pest and pathogen attack and can also influence induced defense responses. In addition, they have a variety of important pharmacological properties, including anticancer activity. The biological mechanisms underpinning the varied and diverse effects of saponins on microbes, plants, and animals are only poorly understood despite the ecological and pharmaceutical importance of this major class of plant secondary metabolites. Here we have exploited budding yeast (Saccharomyces cerevisiae) to investigate the effects of saponins on eukaryotic cells. The tomato steroidal glycoalkaloid alpha-tomatine has antifungal activity towards yeast, and this activity is associated with membrane permeabilization. Removal of a single sugar from the tetrasaccharide chain of alpha-tomatine results in a substantial reduction in antimicrobial activity. Surprisingly, the complete loss of sugars leads to enhanced antifungal activity. Experiments with alpha-tomatine and its aglycone tomatidine indicate that the mode of action of tomatidine towards yeast is distinct from that of alpha-tomatine and does not involve membrane permeabilization. Investigation of the effects of tomatidine on yeast by gene expression and sterol analysis indicate that tomatidine inhibits ergosterol biosynthesis. Tomatidine-treated cells accumulate zymosterol rather than ergosterol, which is consistent with inhibition of the sterol C(24) methyltransferase Erg6p. However, erg6 and erg3 mutants (but not erg2 mutants) have enhanced resistance to tomatidine, suggesting a complex interaction of erg mutations, sterol content, and tomatidine resistance. PMID:16870766

Simons, Veronika; Morrissey, John P; Latijnhouwers, Maita; Csukai, Michael; Cleaver, Adam; Yarrow, Carol; Osbourn, Anne

2006-08-01

223

Do replication forks control late origin firing in Saccharomyces cerevisiae?  

PubMed Central

Recent studies of eukaryotic DNA replication timing profiles suggest that the time-dependent rate of origin firing, I(t), has a universal shape, which ensures a reproducible replication completion time. However, measurements of I(t) are based on population averages, which may bias the shape of the I(t) because of imperfect cell synchrony and cell-to-cell variability. Here, we measure the population-averaged I(t) profile from synchronized Saccharomyces cerevisiae cells using DNA combing and we extract the single-cell I(t) profile using numerical deconvolution. The single cell I(t) and the population-averaged I(t) extracted from DNA combing and replication timing profiles are similar, indicating a genome scale invariance of the replication process, and excluding cell-to-cell variability in replication time as an explanation for the shape of I(t). The single cell I(t) correlates with fork density in wild-type cells, which is specifically loosened in late S phase in the clb5? mutant. A previously proposed numerical model that reproduces the wild-type I(t) profile, could also describe the clb5? mutant I(t) once modified to incorporate the decline in CDK activity and the looser dependency of initiation on fork density in the absence of Clb5p. Overall, these results suggest that the replication forks emanating from early fired origins facilitate origin firing in later-replicating regions.

Ma, Emilie; Hyrien, Olivier; Goldar, Arach

2012-01-01

224

Sulfate assimilation mediates tellurite reduction and toxicity in Saccharomyces cerevisiae.  

PubMed

Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism. PMID:20675578

Ottosson, Lars-Gran; Logg, Katarina; Ibstedt, Sebastian; Sunnerhagen, Per; Kll, Mikael; Blomberg, Anders; Warringer, Jonas

2010-10-01

225

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae?  

PubMed Central

Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism.

Ottosson, Lars-Goran; Logg, Katarina; Ibstedt, Sebastian; Sunnerhagen, Per; Kall, Mikael; Blomberg, Anders; Warringer, Jonas

2010-01-01

226

Kem Mutations Affect Nuclear Fusion in Saccharomyces Cerevisiae  

PubMed Central

We have identified mutations in three genes of Saccharomyces cerevisiae, KEM1, KEM2 and KEM3, that enhance the nuclear fusion defect of kar1-1 yeast during conjugation. The KEM1 and KEM3 genes are located on the left arm of chromosome VII. Kem mutations reduce nuclear fusion whether the kem and the kar1-1 mutations are in the same or in different parents (i.e., in both kem kar1-1 X wild-type and kem X kar1-1 crosses). kem1 X kem1 crosses show a defect in nuclear fusion, but kem1 X wild-type crosses do not. Mutant kem1 strains are hypersensitive to benomyl, lose chromosomes at a rate 10-20-fold higher than KEM(+) strains, and lose viability upon nitrogen starvation. In addition, kem1/kem1 diploids are unable to sporulate. Cells containing a kem1 null allele grow very poorly, have an elongated rod-shape and are defective in spindle pole body duplication and/or separation. The KEM1 gene, which is expressed as a 5.5-kb mRNA transcript, contains a 4.6-kb open reading frame encoding a 175-kD protein.

Kim, J.; Ljungdahl, P. O.; Fink, G. R.

1990-01-01

227

Regulators of Cellular Levels of Histone Acetylation in Saccharomyces cerevisiae  

PubMed Central

Histone acetylation levels are regulated through the opposing activities of histone acetyltransferases (HATs) and deacetylases (HDACs). While much is known about gene-specific control of histone acetylation, little is understood about how total or cellular levels of histone acetylation are regulated. To identify regulators of cellular levels of histone acetylation, we developed an immunofluorescence-based approach to screen the single-gene deletion library of Saccharomyces cerevisiae for strains with significant reductions in cellular histone acetylation levels. Of the 4848 mutants screened, we identified 63 strains with considerable cellular hypoacetylation of N-terminal lysines in histones H3 and H4. The cellular hypoacetylation was validated for subsets of the identified strains through secondary screens including mass spectrometric analysis of individual lysines and chromatin immunoprecipitation of specific genomic loci. Among the identified mutants were several members of the Ccr4-Not complex, V-type ATPases, and vacuolar protein-sorting complexes as well as genes with unknown functions. We show that Gcn5, a major HAT in yeast, has diminished histone acetyltransferase activity in particular mutants, providing a plausible explanation for reduction of cellular acetylation levels in vivo. Our findings have revealed unexpected and novel links between histone acetylation, Gcn5 HAT activity, and diverse processes such as transcription, cellular ion homeostasis, and protein transport.

Peng, Weimin; Togawa, Cynthia; Zhang, Kangling; Kurdistani, Siavash K.

2008-01-01

228

The genes for fifteen ribosomal proteins of Saccharomyces cerevisiae.  

PubMed

We have isolated recombinant lambda phage carrying the genes for 14 of the ribosomal proteins of the yeast Saccharomyces cerevisiae. Analysis of these and of the plasmid carrying the gene tcm1, which codes for the ribosomal protein responsible for resistance to trichodermin, demonstrates that in general the genes for ribosomal proteins are unlinked. One exceptional recombinant carries the genes for two ribosomal proteins within a 2-kilobase region. DNA fragments bearing individual ribosomal protein genes were used to probe restriction digests of the yeast genome to determine whether any of the genes were duplicated. Only 3 of 12 of the genes are present unequivocally as a single copy. Similar fragments were used to probe blots of mRNA separated on denaturing agarose gels to determine the size of the mRNA for each protein. In each case, the mRNA is near the minimum size necessary to code for its protein. In certain temperature-sensitive mutants which fail to synthesize functional mRNA for ribosomal protein, Rosbash et al. (Rosbash, M., Harris, P. K. W., Woolford, J., and Teem, J. L. (1981) Cell, 24, 679-686) have demonstrated the accumulation of a larger RNA molecule, homologous to a ribosomal protein gene, that appears to be a transcript which retains an intervening sequence. We find that for 8 of the 11 ribosomal protein genes examined, a larger molecule accumulates in such a mutant strain, suggesting that in general transcripts of ribosomal protein genes may have introns. PMID:6268628

Fried, H M; Pearson, N J; Kim, C H; Warner, J R

1981-10-10

229

Conversion of Wine Strains of Saccharomyces cerevisiae to Heterothallism  

PubMed Central

A general method to convert homothallic strains of the yeast Saccharomyces cerevisiae to heterothallism is described which is applicable to genetically well-behaved diploids, as well as to strains that sporulate poorly or produce few viable and mating-competent spores. The heterothallic (ho) allele was introduced into three widely used wine strains through spore cell hybridization. The resultant hybrids were sporulated, and heterothallic segregants were isolated for use in successive backcrosses. Heterothallic progeny of opposite mating type and monosomic for chromosome III produced by sixth-backcross hybrids or their progeny were mated together to reconstruct heterothallic derivatives of the wine strain parents. A helpful prerequisite to the introduction of ho was genetic purification of the parental strains based on repeated cycles of sporulation, ascus dissection, and clonal selection. A positive selection to isolate laboratory-wine strain hybrids requiring no prior genetic alteration of the industrial strains, coupled with a partial selection to reduce the number of spore progeny needed to be screened to isolate heterothallic segregants of the proper genotype made the procedure valuable for genetically intractable strains. Trial grape juice fermentations indicated that introduction of ho had no deleterious effect on fermentation behavior.

Bakalinsky, Alan T.; Snow, Richard

1990-01-01

230

Identification of Genes Affecting Hydrogen Sulfide Formation in Saccharomyces cerevisiae?  

PubMed Central

A screen of the Saccharomyces cerevisiae deletion strain set was performed to identify genes affecting hydrogen sulfide (H2S) production. Mutants were screened using two assays: colony color on BiGGY agar, which detects the basal level of sulfite reductase activity, and production of H2S in a synthetic juice medium using lead acetate detection of free sulfide in the headspace. A total of 88 mutants produced darker colony colors than the parental strain, and 4 produced colonies significantly lighter in color. There was no correlation between the appearance of a dark colony color on BiGGY agar and H2S production in synthetic juice media. Sixteen null mutations were identified as leading to the production of increased levels of H2S in synthetic juice using the headspace analysis assay. All 16 mutants also produced H2S in actual juices. Five of these genes encode proteins involved in sulfur containing amino acid or precursor biosynthesis and are directly associated with the sulfate assimilation pathway. The remaining genes encode proteins involved in a variety of cellular activities, including cell membrane integrity, cell energy regulation and balance, or other metabolic functions. The levels of hydrogen sulfide production of each of the 16 strains varied in response to nutritional conditions. In most cases, creation of multiple deletions of the 16 mutations in the same strain did not lead to a further increase in H2S production, instead often resulting in decreased levels.

Linderholm, Angela L.; Findleton, Carrie L.; Kumar, Gagandeep; Hong, Yeun; Bisson, Linda F.

2008-01-01

231

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

232

Functional annotations for the Saccharomyces cerevisiae genome: the knowns and the known unknowns  

PubMed Central

The quest to characterize each of the genes of the yeast Saccharomyces cerevisiae has propelled the development and application of novel high-throughput (HTP) experimental techniques. To handle the enormous amount of information generated by these techniques, new bioinformatics tools and resources are needed. Gene Ontology (GO) annotations curated by the Saccharomyces Genome Database (SGD) have facilitated the development of algorithms that analyze HTP data and help predict functions for poorly characterized genes in S. cerevisiae and other organisms. Here, we describe how published results are incorporated into GO annotations at SGD and why researchers can benefit from using these resources wisely to analyze their HTP data and predict gene functions.

Christie, Karen R.; Hong, Eurie L.; Cherry, J. Michael

2011-01-01

233

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.

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

2011-01-01

234

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.

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

2005-01-01

235

Coordinate regulation of phosphatidylserine decarboxylase in Saccharomyces cerevisiae.  

PubMed Central

Regulation of the activity of the mitochondrial enzyme phosphatidylserine decarboxylase (PSD) was measured in vitro by using membrane preparations from wild-type and mutant strains of Saccharomyces cerevisiae. PSD specific activity was not affected by carbon source, and on all carbon sources, the highest specific activity was observed in cells entering the stationary phase of growth. However, PSD activity was found to be regulated in response to soluble precursors of phospholipid biosynthesis. PSD specific activity was reduced to about 63% of the level observed in unsupplemented wild-type cells when the cells were grown in the presence of 75 microM inositol. The presence of 1 mM choline alone had no repressing effect, but the presence of 1 mM choline and 75 microM inositol together led to further repression to a level of about 28% of the derepressed activity. Regulatory mutations known to affect regulation or expression of genes encoding phospholipid-synthesizing enzymes also affected PSD specific activity. opi1 mutants, which are constitutive for a number of phospholipid-biosynthetic enzymes, were found to have high, constitutive levels of PSD. Likewise, in ino2 or ino4 regulatory mutants, PSD activity was found to be at the fully repressed level regardless of growth condition. Regulation of PSD activity was also affected in several structural-gene mutants under conditions of impaired phosphatidylcholine biosynthesis. Together, these data strongly suggest that PSD expression is controlled by the mechanism of general control of phospholipid biosynthesis that regulates many enzymes of phospholipid biosynthesis.

Lamping, E; Kohlwein, S D; Henry, S A; Paltauf, F

1991-01-01

236

Genetics of a-agglutunin function in Saccharomyces cerevisiae.  

PubMed

The Saccharomyces cerevisiae cell adhesion protein a-agglutinin is composed of an anchorage subunit (Aga1p) and an adhesion subunit (Aga2p). Although functional a-agglutinin is expressed only by a cells, previous results indicated that AGA1 RNA is expressed in both a and alpha cells after pheromone induction. Expression of the Aga2p adhesion subunit in alpha cells allowed a-agglutinability, indicating that alpha cells express the a-agglutinin anchorage subunit, although no role for Aga1p in alpha cells has been identified. Most of the a-specific agglutination-defective mutants isolated previously were defective in AGA1; a single mutant (La199) was a candidate for an aga2 mutant. Expression of AGA2 under PGK control allowed secretion of active Aga2p from control strains but did not complement the La199 agglutination defect or allow secretion of Aga2p from La199, suggesting that the La199 mutation might identify a new gene required for a-agglutinin function. However, the La199 agglutination defect showed tight linkage to aga2::URA3 and did not complement aga2::URA3 in a/a diploids. The aga2 gene cloned from La199 was nonfunctional and contained an ochre mutation. The inability of pPGK-AGA2 to express functional Aga2p in La199 was shown to result from an additional mutation(s) that reduces expression of plasmid-borne genes. AGA2 was mapped to the left arm of chromosome VII approximately 28 cM from the centromere. PMID:7770047

de Nobel, H; Pike, J; Lipke, P N; Kurjan, J

1995-05-20

237

Competing crossover pathways act during meiosis in Saccharomyces cerevisiae.  

PubMed

In Saccharomyces cerevisiae the MSH4-MSH5, MLH1-MLH3, and MUS81-MMS4 complexes act to promote crossing over during meiosis. MSH4-MSH5, but not MUS81-MMS4, promotes crossovers that display interference. A role for MLH1-MLH3 in crossover control is less clear partly because mlh1Delta mutants retain crossover interference yet display a decrease in crossing over that is only slightly less severe than that seen in msh4Delta and msh5Delta mutants. We analyzed the effects of msh5Delta, mlh1Delta, and mms4Delta single, double, and triple mutants on meiotic crossing over at four consecutive genetic intervals on chromosome XV using newly developed computer software. mlh1Delta mms4Delta double mutants displayed the largest decrease in crossing over (13- to 15-fold) of all mutant combinations, yet these strains displayed relatively high spore viability (42%). In contrast, msh5Delta mms4Delta and msh5Delta mms4Delta mlh1Delta mutants displayed smaller decreases in crossing over (4- to 6-fold); however, spore viability (18-19%) was lower in these strains than in mlh1Delta mms4Delta strains. These data suggest that meiotic crossing over can occur in yeast through three distinct crossover pathways. In one pathway, MUS81-MMS4 promotes interference-independent crossing over; in a second pathway, both MSH4-MSH5 and MLH1-MLH3 promote interference-dependent crossovers. A third pathway, which appears to be repressed by MSH4-MSH5, yields deleterious crossovers. PMID:15611158

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

2004-12-01

238

Genetic Analysis of Desiccation Tolerance in Saccharomyces cerevisiae  

PubMed Central

Desiccation tolerance, the ability to survive nearly total dehydration, is a rare strategy for survival and reproduction observed in all taxa. However, the mechanism and regulation of this phenomenon are poorly understood. Correlations between desiccation tolerance and potential effectors have been reported in many species, but their physiological significance has not been established in vivo. Although the budding yeast Saccharomyces cerevisiae exhibits extreme desiccation tolerance, its usefulness has been hampered by an inability to reduce tolerance more than a few fold by physiological or genetic perturbations. Here we report that fewer than one in a million yeast cells from low-density logarithmic cultures survive desiccation, while 2040% of cells from saturated cultures survive. Using this greatly expanded metric, we show that mutants defective in trehalose biosynthesis, hydrophilins, responses to hyperosmolarity, and hypersalinity, reactive oxygen species (ROS) scavenging and DNA damage repair nevertheless retain wild-type levels of desiccation tolerance, suggesting that this trait involves a unique constellation of stress factors. A genome-wide screen for mutants that render stationary cells as sensitive as log phase cells identifies only mutations that block respiration. Respiration as a prerequisite for acquiring desiccation tolerance is corroborated by respiration inhibition and by growth on nonfermentable carbon sources. Suppressors bypassing the respiration requirement for desiccation tolerance reveal at least two pathways, one of which, involving the Mediator transcription complex, is associated with the shift from fermentative to respiratory metabolism. Further study of these regulators and their targets should provide important clues to the sensors and effectors of desiccation tolerance.

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

2011-01-01

239

Biophysical characterization of elongin C from Saccharomyces cerevisiae.  

PubMed

Elongin C (ELC) is an essential component of the mammalian CBC(VHL) E3 ubiquitin ligase complex. As a step toward understanding the role of ELC in assembly and function of CBC-type ubiquitin ligases, we analyzed the quaternary structure and backbone dynamics of the highly homologous Elc1 protein from Saccharomyces cerevisiae. Analytical ultracentrifugation experiments in conjunction with size exclusion chromatography showed that Elc1 is a nonglobular monomer over a wide range of concentrations. Pronounced line broadening in (1)H,(15)N-HSQC NMR spectra and failure to assign peaks corresponding to the carboxy-terminal helix 4 of Elc1 indicated that helix 4 is conformationally labile. Measurement of (15)N NMR relaxation parameters including T(1), T(2), and the (1)H-(15)N nuclear Overhauser effect revealed (i) surprisingly high flexibility of residues 69-77 in loop 5, and (ii) chemical exchange contributions for a large number of residues throughout the protein. Addition of 2,2,2-trifluoroethanol (TFE) stabilized helix 4 and reduced chemical exchange contributions, suggesting that stabilization of helix 4 suppresses the tendency of Elc1 to undergo conformational exchange on a micro- to millisecond time scale. Binding of a peptide representing the major ELC binding site of the von Hippel-Lindau (VHL) tumor suppressor protein almost completely eliminated chemical exchange processes, but induced substantial conformational changes in Elc1 leading to pronounced rotational anisotropy. These results suggest that elongin C interacts with various target proteins including the VHL protein by an induced fit mechanism involving the conformationally flexible carboxy-terminal helix 4. PMID:10998253

Buchberger, A; Howard, M J; Freund, S M; Proctor, M; Butler, P J; Fersht, A R; Bycroft, M

2000-09-12

240

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

241

Utilization of D-asparagine by Saccharomyces cerevisiae.  

PubMed

Yeast strains sigma1278b and Harden and Young, which synthesize only an internal constitutive form of L-asparaginase, do not grow on D-asparagine, as a sole source of nitrogen, and whole cell suspensions of these strains do not hydrolyze D-asparagine. Strains X2180-A2 and D273-10B, which possess an externally active form of asparaginase, are able to grow slowly on D-asparagine, and nitrogen-starved suspensions of these strains exhibit high activity toward the D-isomer. Nitrogen starvation of strain X218O-A2 results in coordinate increase of D- and L-asparaginase activity; the specific activity observed for the D-isomer is approximately 20% greater than that observed for the L-isomer. It was observed, in studies with cell extracts, that hydrolysis of D-asparagine occurred only with extracts from nitrogen-starved cells of strains that synthesize the external form of asparaginase. Furthermore, the activity of the extracts toward the D-isomer was always higher than that observed with the L-isomer. A 400-fold purified preparation of external asparaginase from Saccharomyces cerevisiae X218U-A2 hydrolyzed D-asparagine with an apparent Km of 0.23 mM and a Vmax of 38.7 mumol/min per mg of protein. D-Asparagine was a competitive inhibitor of L-asparagine hydrolysis and the Ki determined for this inhibition was approximately equal to its Km. These data suggest that D-asparagine is a good substrate for the external yeast asparaginase but is a poor substrate for the internal enzyme. PMID:767332

Dunlop, P C; Roon, R J; Even, H L

1976-03-01

242

Molecular Analysis of Maltotriose Transport and Utilization by Saccharomyces cerevisiae  

PubMed Central

Efficient fermentation of maltotriose is a desired property of Saccharomyces cerevisiae for brewing. In a standard wort, maltotriose is the second most abundant sugar, and slower uptake leads to residual maltotriose in the finished product. The limiting factor of sugar metabolism is its transport, and there are conflicting reports on whether a specific maltotriose permease exists or whether the mechanisms responsible for maltose uptake also carry out maltotriose transport. In this study, radiolabeled maltotriose was used to show that overexpression of the maltose permease gene, MAL61, in an industrial yeast strain resulted in an increase in the rate of transport of maltotriose as well as maltose. A strain derived from W303-1A and lacking any maltose or maltotriose transporter but carrying a functional maltose transport activator (MAL63) was developed. By complementing this strain with permeases encoded by MAL31, MAL61, and AGT1, it was possible to measure their specific transport kinetics by using maltotriose and maltose. All three permeases were capable of high-affinity transport of maltotriose and of allowing growth of the strain on the sugar. Maltotriose utilization from the permease encoded by AGT1 was regulated by the same genetic mechanisms as those involving the maltose transcriptional activator. Competition studies carried out with two industrial strains, one not containing any homologue of AGT1, showed that maltose uptake and maltotriose uptake were competitive and that maltose was the preferred substrate. These results indicate that the presence of residual maltotriose in beer is not due to a genetic or physiological inability of yeast cells to utilize the sugar but rather to the lower affinity for maltotriose uptake in conjunction with deteriorating conditions present at the later stages of fermentation. Here we identify molecular mechanisms regulating the uptake of maltotriose and determine the role of each of the transporter genes in the cells.

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

2002-01-01

243

Characterization of Glycogen-Deficient Glc Mutants of Saccharomyces Cerevisiae  

PubMed Central

Forty-eight mutants of Saccharomyces cerevisiae with defects in glycogen metabolism were isolated. The mutations defined eight GLC genes, the functions of which were determined. Mutations in three of these genes activate the RAS/cAMP pathway either by impairment of a RAS GTPase-activating protein (GLC1/IRA1 and GLC4/IRA2) or by activating Ras2p (GLC5/RAS2). SNF1 protein kinase (GLC2) was found to be required for normal glycogen levels. Glycogen branching enzyme (GLC3) was found to be required for significant glycogen synthesis. GLC6 was shown to be allelic to CIF1 (and probably FDP1, BYP1 and GGS1), mutations in which were previously found to prevent growth on glucose; this gene is also the same as TPS1, which encodes a subunit of the trehalose-phosphate synthase. Mutations in GLC6 were capable of increasing or decreasing glycogen levels, at least in part via effects on the regulation of glycogen synthase. GLC7 encodes a type 1 protein phosphatase that contributes to the dephosphorylation (and hence activation) of glycogen synthase. GLC8 encodes a homologue of type 1 protein phosphatase inhibitor-2. The genetic map positions of GLC1/IRA1, GLC3, GLC4/IRA2, GLC6/CIF1/TPS1 (and the adjacent VAT2/VMA2), and GLC7 were clarified. From the data on GLC3, there may be a suppression of recombination near the chromosome V centromere, at least in some strains.

Cannon, J. F.; Pringle, J. R.; Fiechter, A.; Khalil, M.

1994-01-01

244

The anatomy of a hypoxic operator in Saccharomyces cerevisiae.  

PubMed Central

Aerobic repression of the hypoxic genes of Saccharomyces cerevisiae is mediated by the DNA-binding protein Rox1 and the Tup1/Ssn6 general repression complex. To determine the DNA sequence requirements for repression, we carried out a mutational analysis of the consensus Rox1-binding site and an analysis of the arrangement of the Rox1 sites into operators in the hypoxic ANB1 gene. We found that single base pair substitutions in the consensus sequence resulted in lower affinities for Rox1, and the decreased affinity of Rox1 for mutant sites correlated with the ability of these sites to repress expression of the hypoxic ANB1 gene. In addition, there was a general but not complete correlation between the strength of repression of a given hypoxic gene and the compliance of the Rox1 sites in that gene to the consensus sequence. An analysis of the ANB1 operators revealed that the two Rox1 sites within an operator acted synergistically in vivo, but that Rox1 did not bind cooperatively in vitro, suggesting the presence of a higher order repression complex in the cell. In addition, the spacing or helical phasing of the Rox1 sites was not important in repression. The differential repression by the two operators of the ANB1 gene was found to be due partly to the location of the operators and partly to the sequences between the two Rox1-binding sites in each. Finally, while Rox1 repression requires the Tup1/Ssn6 general repression complex and this complex has been proposed to require the aminoterminal regions of histones H3 and H4 for full repression of a number of genes, we found that these regions were dispensable for ANB1 repression and the repression of two other hypoxic genes.

Deckert, J; Torres, A M; Hwang, S M; Kastaniotis, A J; Zitomer, R S

1998-01-01

245

A vector set for systematic metabolic engineering in Saccharomyces cerevisiae  

PubMed Central

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 ?-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.

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

2011-01-01

246

Saccharomyces cerevisiae Vacuole in Zinc Storage and Intracellular Zinc Distribution?  

PubMed Central

Previous studies of the yeast Saccharomyces cerevisiae indicated that the vacuole is a major site of zinc storage in the cell. However, these studies did not address the absolute level of zinc that was stored in the vacuole nor did they examine the abundances of stored zinc in other compartments of the cell. In this report, we describe an analysis of the cellular distribution of zinc by use of both an organellar fractionation method and an electron probe X-ray microanalysis. With these methods, we determined that zinc levels in the vacuole vary with zinc status and can rise to almost 100 mM zinc (i.e., 7 108 atoms of vacuolar zinc per cell). Moreover, this zinc can be mobilized effectively to supply the needs of as many as eight generations of progeny cells under zinc starvation conditions. While the Zrc1 and Cot1 zinc transporters are essential for zinc uptake into the vacuole under steady-state growth conditions, additional transporters help mediate zinc uptake into the vacuole during zinc shock, when zinc-limited cells are resupplied with zinc. In addition, we found that other compartments of the cell do not provide significant stores of zinc. In particular, zinc accumulation in mitochondria is low and is homeostatically regulated independently of vacuolar zinc storage. Finally, we observed a strong correlation between zinc status and the levels of magnesium and phosphorus accumulated in cells. Our results implicate zinc as a major determinant of the ability of the cell to store these other important nutrients.

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

2007-01-01

247

Saccharomyces cerevisiae vacuole in zinc storage and intracellular zinc distribution.  

PubMed

Previous studies of the yeast Saccharomyces cerevisiae indicated that the vacuole is a major site of zinc storage in the cell. However, these studies did not address the absolute level of zinc that was stored in the vacuole nor did they examine the abundances of stored zinc in other compartments of the cell. In this report, we describe an analysis of the cellular distribution of zinc by use of both an organellar fractionation method and an electron probe X-ray microanalysis. With these methods, we determined that zinc levels in the vacuole vary with zinc status and can rise to almost 100 mM zinc (i.e., 7 x 10(8) atoms of vacuolar zinc per cell). Moreover, this zinc can be mobilized effectively to supply the needs of as many as eight generations of progeny cells under zinc starvation conditions. While the Zrc1 and Cot1 zinc transporters are essential for zinc uptake into the vacuole under steady-state growth conditions, additional transporters help mediate zinc uptake into the vacuole during "zinc shock," when zinc-limited cells are resupplied with zinc. In addition, we found that other compartments of the cell do not provide significant stores of zinc. In particular, zinc accumulation in mitochondria is low and is homeostatically regulated independently of vacuolar zinc storage. Finally, we observed a strong correlation between zinc status and the levels of magnesium and phosphorus accumulated in cells. Our results implicate zinc as a major determinant of the ability of the cell to store these other important nutrients. PMID:17526722

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

2007-07-01

248

Vesicular transport of extracellular acid phosphatases in yeast Saccharomyces cerevisiae.  

PubMed

A method for isolation of secretory vesicles from the yeast Saccharomyces cerevisiae based on the disintegration of protoplasts by osmotic shock followed by separation of the vesicles by centrifugation in a density gradient of Urografin was developed in this study. Two populations of the secretory vesicles that differ in density and shape were separated. Acid phosphatases (EC 3.1.3.2) were used as markers of the secretory vesicles. It was shown that the constitutive acid phosphatase (PHO3 gene product) is mainly transported to the cell surface by a lower density population of vesicles, while the repressible acid phosphatase (a heteromer encoded by PHO5, PHO10, and PHO11 genes) by a vesicle population of higher density. These data provide evidence that at least two pathways of transport of yeast secretory proteins from the place of their synthesis and maturation to the cell surface may exist. To reveal the probable reasons for transport of Pho3p and Pho5p/Pho10p/Pho11p enzymes by two different kinds of vesicles, we isolated vesicles from strains that synthesize the homomeric forms of the repressible acid phosphatase. It was demonstrated that glycoproteins encoded by the PHO10 and/or PHO11 genes could be responsible for the choice of one of the alternative transport pathways of the repressible acid phosphatase. A high correlation coefficient between bud formation and secretion of Pho5p phosphatase and the absence of correlation between bud formation and secretion of minor phosphatases Pho10p and Pho11p suggests different functional roles of the polypeptides that constitute the native repressible acid phosphatase. PMID:11996663

Blinnikova, E I; Mirjuschenko, F L; Shabalin, Yu A; Egorov, S N

2002-04-01

249

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.

2014-01-01

250

Membrane stress caused by octanoic acid in Saccharomyces cerevisiae.  

PubMed

In order to compete with petroleum-based fuel and chemicals, engineering a robust biocatalyst that can convert renewable feedstocks into biorenewable chemicals, such as carboxylic acids, is increasingly important. However, product toxicity is often problematic. In this study, the toxicity of the carboxylic acids hexanoic, octanoic, and decanoic acid on Saccharomyces cerevisiae was investigated, with a focus on octanoic acid. These compounds are completely inhibitory at concentrations of magnitude 1mM, and the toxicity increases as chain length increases and as media pH decreases. Transciptome analysis, reconstruction of gene regulatory network, and network component analysis suggested decreased membrane integrity during challenge with octanoic acid. This was confirmed by quantification of dose-dependent and chain length-dependent induction of membrane leakage, though membrane fluidity was not affected. This induction of membrane leakage could be significantly decreased by a period of pre-adaptation, and this pre-adaptation was accompanied by increased oleic acid content in the membrane, significantly increased production of saturated lipids relative to unsaturated lipids, and a significant increase in the average lipid chain length in the membrane. However, during adaptation cell surface hydrophobicity was not altered. The supplementation of oleic acid to the medium not only elevated the tolerance of yeast cells to octanoic acid but also attenuated the membrane leakiness. However, while attempts to mimic the oleic acid supplementation effects through expression of the Trichoplusia ni acyl-CoA ?9 desaturase OLE1(TniNPVE desaturase) were able to increase the oleic acid content, the magnitude of the increase was not sufficient to reproduce the supplementation effect and increase octanoic acid tolerance. Similarly, introduction of cyclopropanated fatty acids through expression of the Escherichia coli cfa gene was not helpful for tolerance. Thus, we have provided quantitative evidence that carboxylic acids damage the yeast membrane and that manipulation of the lipid content of the membrane can increase tolerance, and possibly production, of these valuable products. PMID:23435986

Liu, Ping; Chernyshov, Andriy; Najdi, Tarek; Fu, Yao; Dickerson, Julie; Sandmeyer, Suzanne; Jarboe, Laura

2013-04-01

251

Regulation of isoleucine-valine biosynthesis in Saccharomyces cerevisiae.  

PubMed

The threonine deaminase gene (ILV1) of Saccharomyces cerevisiae has been designated "multifunctional" since Bollon (1974) indicated its involvement both in the catalysis of the first step in isoleucine biosynthesis and in the regulation of the isoleucine-valine pathway. Its role in regulation is characterized by a decrease in the activity of the five isoleucine-valine enzymes when cells are grown in the presence of the three branched-chain amino acids, isoleucine, valine and leucine (multivalent repression). We have demonstrated that the regulation of AHA reductoisomerase (encoded by ILV5) and branched-chain amino acid transaminase is unaffected by the deletion of ILV1, subsequently revealing that the two enzymes can be regulated in the absence of threonine deaminase. Both threonine deaminase activity and ILV1 mRNA levels increase in mutants (gcd2 and gcd3) having constitutively depressed levels of enzymes under the general control of amino acid biosynthesis, as well as in response to starvation for tryptophan and branched-chain amino acid imbalance. Thus, the ILV1 gene is under general amino acid control, as is the case for both the ILV5 and the transaminase gene. Multivalent repression of reductoisomerase and transaminase can be observed in mutants defective in general control (gcn and gcd), whereas this is not the case for threonine deaminase. Our analysis suggests that repression effected by general control is not complete in minimal medium. Amino acid dependent regulation of threonine deaminase is only through general control, while the branched-chain amino acid repression of AHA reducto isomerase and the transaminase is caused both by general control and an amino acid-specific regulation. PMID:3289762

Holmberg, S; Petersen, J G

1988-03-01

252

Expression of human placental aromatase in Saccharomyces cerevisiae.  

PubMed

A full-length human placental aromatase cDNA clone, Aro 2, was isolated upon screening a human placental cDNA library with an aromatase cDNA probe and an oligonucleotide probe whose sequence was derived from a human aromatase genomic clone. Nucleotide sequence microheterogeneity was found in the 3'-untranslated region among Aro 2 and in two previously described human aromatase cDNA clones. Both the minor sequence differences and the expression of a single protein species in placental tissue suggest the presence of different alleles for aromatase. Northern blot analyses using one cDNA and two oligonucleotide probes are consistent with the two mRNA messages of 2.9 and 2.5 kilobases arising in human placenta as a consequence of differential processing. Several yeast expression plasmids containing the aromatase cDNA we cloned were constructed. The enzyme was expressed in Saccharomyces cerevisiae. The expressed activity was inhibited by the known aromatase inhibitor, 4-hydroxyandrostenedione. A level of 2 micrograms aromatase/mg partially purified yeast microsomes was estimated by analyses of carbon monoxide difference spectra on microsomal fractions from yeast carrying plasmid pHARK/VGAL. Using [1 beta, 2 beta-3H]androst-4-ene-3,17-dione as the substrate, an apparent Michaels-Menken constant (Km) of 34 nM and a maximum velocity (Vmax) of 23 pmol [3H]water formed per min/mg protein were obtained for the yeast synthesized aromatase by transformation with plasmid pHARK/VGAL. The kinetic results are similar to those determined for human placental aromatase, and suggest that the yeast synthesized aromatase will be useful for further structure-function studies. PMID:2691883

Pompon, D; Liu, R Y; Besman, M J; Wang, P L; Shively, J E; Chen, S

1989-09-01

253

Saccharomyces cerevisiae genes involved in survival of heat shock.  

PubMed

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

2013-12-01

254

Regulation of cardiolipin synthase levels in Saccharomyces cerevisiae  

PubMed Central

The Saccharomyces cerevisiae cardiolipin (CL) synthase encoded by the CRD1 gene catalyses the synthesis of CL, which is localized to the inner mitochondrial membrane and plays an important role in mitochondrial function. To investigate how CRD1 expression is regulated, a lacZ reporter gene was placed under control of the CRD1 promoter and the 5?-untranslated region of its mRNA (PCRD1-lacZ). PCRD1-lacZ expression was 2.5 times higher in early stationary phase than in logarithmic phase for glucose grown cells. Non-fermentable growth resulted in a two-fold elevation in expression relative to glucose grown cells. A shift from glycerol to glucose rapidly repressed expression, whereas a shift from glucose to glycerol had the opposite effect. The derepression of PCRD1-lacZ expression by non-fermentable carbon sources was dependent on mitochondrial respiration. These results support a tight coordination between translation and transcription of the CRD1 gene, since similar effects by the above factors on CRD1 mRNA levels have been reported. In glucose-grown cells, PCRD1-lacZ expression was repressed 70% in a pgs1? strain (lacks phosphatidylglycerol and CL) compared with wild-type and rho? cells and elevated 2.5-fold in crd1? cells, which have increased phosphatidylglycerol levels, suggesting a role for phosphatidylglycerol in regulating CRD1 expression. Addition of inositol to the growth medium had no effect on expression. However, expression was elevated in an ino4? mutant but not in ino2? cells, suggesting multiple and separate functions for the inositol-responsive INO2/INO4 gene products, which normally function as a dimer in regulating gene function.

Su, Xuefeng; Dowhan, William

2014-01-01

255

Topological and Mutational Analysis of Saccharomyces cerevisiae Fks1  

PubMed Central

Fks1, with orthologs in nearly all fungi as well as plants and many protists, plays a central role in fungal cell wall formation as the putative catalytic component of ?-1,3-glucan synthase. It is also the target for an important new antifungal group, the echinocandins, as evidenced by the localization of resistance-conferring mutations to Fks1 hot spots 1, 2, and 3 (residues 635 to 649, 1354 to 1361, and 690 to 700, respectively). Since Fks1 is an integral membrane protein and echinocandins are cyclic peptides with lipid tails, Fks1 topology is key to understanding its function and interaction with echinocandins. We used hemagglutinin (HA)-Suc2-His4C fusions to C-terminally truncated Saccharomyces cerevisiae Fks1 to experimentally define its topology and site-directed mutagenesis to test function of selected residues. Of the 15 to 18 transmembrane helices predicted in silico for Fks1 from evolutionarily diverse fungi, 13 were experimentally confirmed. The N terminus (residues 1 to 445) is cytosolic and the C terminus (residues 1823 to 1876) external; both are essential to Fks1 function. The cytosolic central domain (residues 715 to 1294) includes newly recognized homology to glycosyltransferases, and residues potentially involved in substrate UDP-glucose binding and catalysis are essential. All three hot spots are external, with hot spot 1 adjacent to and hot spot 3 largely embedded within the outer leaflet of the membrane. This topology suggests a model in which echinocandins interact through their lipid tails with hot spot 3 and through their cyclic peptides with hot spots 1 and 2.

Edlind, Thomas D.

2012-01-01

256

Characterization of glycogen-deficient glc mutants of Saccharomyces cerevisiae.  

PubMed

Forty-eight mutants of Saccharomyces cerevisiae with defects in glycogen metabolism were isolated. The mutations defined eight GLC genes, the function of which were determined. Mutations in three of these genes activate the RAS/cAMP pathway either by impairment of a RAS GTPase-activating protein (GLC1/IRA1 and GLC4/IRA2) or by activating Ras2p (GLC5/RAS2). SNF1 protein kinase (GLC2) was found to be required for normal glycogen levels. Glycogen branching enzyme (GLC3) was found to be required for significant glycogen synthesis. GLC6 was shown to be allelic to CIF1 (and probably FDP1, BYP1 and GGS1), mutations in which were previously found to prevent growth on glucose; this gene is also the same as TPS1, which encodes a subunit of the trehalose-phosphate synthase. Mutations in GLC6 were capable of increasing or decreasing glycogen levels, at least in part via effects on the regulation of glycogen synthase. GLC7 encodes a type 1 protein phosphatase that contributes to the dephosphorylation (and hence activation) of glycogen synthase. GLC8 encodes a homologue of type 1 protein phosphatase inhibitor-2. The genetic map positions of GLC1/IRA1, GLC3, GLC4/IRA2, GLC6/CIF1/TPS1 (and the adjacent VAT2/VMA2), and GLC7 were clarified. From the data on GLC3, there may be a suppression of recombination near the chromosome V centromere, at least in some strains. PMID:8150278

Cannon, J F; Pringle, J R; Fiechter, A; Khalil, M

1994-02-01

257

Paralogous histidine biosynthetic genes: evolutionary analysis of the Saccharomyces cerevisiae HIS6 and HIS7 genes  

Microsoft Academic Search

The HIS6 gene from Saccharomyces cerevisiae strain YNN282 is able to complement both the S. cerevisiae his6 and the Escherichia coli hisA mutations. The cloning and the nucleotide sequence indicated that this gene encodes a putative phosphoribosyl-5-amino-1-phosphoribosyl-4-imidazolecarboxiamide isomerase (5? Pro-FAR isomerase, EC 5.3.1.16) of 261 amino acids, with a molecular weight of 29?554. The HIS6 gene product shares a significant

Renato Fani; Elena Tamburini; Elena Mori; Antonio Lazcano; Pietro Li; Claudia Barberio; Enrico Casalone; Duccio Cavalieri; Brunella Perito; Mario Polsinelli

1997-01-01

258

Inhibition of DNA Synthesis in Saccharomyces cerevisiae by Yeast Killer Toxin KT28  

Microsoft Academic Search

Treatment of sensitive cells of Saccharomyces cerevisiae with killer toxin KT28 affected cell viability after 2 h; the effect was dependent upon the availability of a utilizable energy source. Treatment led to an interruption of cell growth. The mother cells contained nuclear DNA, whereas their daughter buds did not. Using a killer-toxin-sensitive thymidine auxotroph of S. cerevisiae carrying a temperature-sensitive

MANFRED SCHMITT; MARTIN BRENDEL; R. SCHWARZ; FERDINAND RADLER

1989-01-01

259

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.

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

1990-01-01

260

Electron paramagnetic resonance studies and effects of vanadium in Saccharomyces cerevisiae  

Microsoft Academic Search

Vanadium uptake by whole cells and isolated cell walls of the yeast Saccharomyces cerevisiae was studied. When orthovanadate was added to wild-type S. cerevisiae cells growing in rich medium, growth was inhibited as a function of the VO43- concentration and the growth was completely arrested at a concentration of 20 mM of VO43- in YEPD. Electron paramagnetic resonance (EPR) spectroscopy

Maria Antonietta Zoroddu; Michelina Fruianu; Roberto Dallocchio; Andreina Masiat

1996-01-01

261

Inactivation of Saccharomyces cerevisiae and Bacillus cereus by pulsed electric fields technology  

Microsoft Academic Search

The effect of pulsed electric field (PEF) treatment, applied in a continuous system, on Saccharomyces cerevisiae and Bacillus cereus cells and spores was investigated. S. cerevisiae inoculated into sterilised apple juice and B. cereus cells and spores inoculated into sterilised 0.15% NaCl were treated with electric field strengths of 1028 kV\\/cm using an 8.3 pulse number and with pulse numbers

Zs. Cserhalmi; I. Vidcs; J. Beczner; B. Czukor

2002-01-01

262

Alcoholic fermentation of carbon sources in biomass hydrolysates by Saccharomyces cerevisiae : current status  

Microsoft Academic Search

Fuel ethanol production from plant biomass hydrolysates by Saccharomyces cerevisiae is of great economic and environmental significance. This paper reviews the current status with respect to alcoholic fermentation of the main plant biomass-derived monosaccharides by this yeast. Wild-type S. cerevisiae strains readily ferment glucose, mannose and fructose via the EmbdenMeyerhof pathway of glycolysis, while galactose is fermented via the Leloir

Antonius J. A. van Maris; Derek A. Abbott; Eleonora Bellissimi; Joost van den Brink; Marko Kuyper; Marijke A. H. Luttik; H. Wouter Wisselink; W. Alexander Scheffers; Johannes P. van Dijken; Jack T. Pronk

2006-01-01

263

Cadmium induces a heterogeneous and caspase-dependent apoptotic response in Saccharomyces cerevisiae  

Microsoft Academic Search

The toxic metal cadmium is linked to a series of degenerative disorders in humans, in which Cd-induced programmed cell death\\u000a (apoptosis) may play a role. The yeast, Saccharomyces cerevisiae, provides a valuable model for elucidating apoptosis mechanisms, and this study extends that capability to Cd-induced apoptosis.\\u000a We demonstrate that S. cerevisiae undergoes a glucose-dependent, programmed cell death in response to

Amrita M. Nargund; Simon V. Avery; John E. Houghton

2008-01-01

264

Hydrolysis and sorption by Saccharomyces cerevisiae strains of Chardonnay grape must glycosides during fermentation  

Microsoft Academic Search

Different Saccharomyces cerevisiae strains were tested for their ability to hydrolyse glycosylglucose (GG) compounds present in Chardonnay must during alcoholic fermentation. The determination of glycosylglucose during the course of the alcoholic fermentation of Chardonnay grape must revealed that S. cerevisiae is able to hydrolyse GG during alcoholic fermentation in wine conditions. The extent of hydrolysis vary from 17 to 57%

David Chassagne; Stphanie Vernizeau; Mustapha Nedjma; Herv Alexandre

2005-01-01

265

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

266

Comparative physiology of salt tolerance in Candida tropicalis and Saccharomyces cerevisiae.  

PubMed

The salt tolerance of the respiratory yeast Candida tropicalis and the fermentative yeast Saccharomyces cerevisiae have been compared in glucose media. C. tropicalis showed a better adaptation to Na+ and Li+ and maintained higher intracellular K+:Na+ and K+:Li+ ratios than S. cerevisiae. However, C. tropicalis showed a poorer adaptation to osmotic stress (produced by KCl and sorbitol) and exhibited reduced glycerol production as compared to S. cerevisiae. In media with the non-repressing sugar galactose as carbon source, S. cerevisiae exhibited reduced glycerol production and increased sensitivity to osmotic stress. Under these conditions, S. cerevisiae, but not C. tropicalis, utilized trehalose as a more important osmolyte than glycerol. These results suggest that the relative tolerance of yeast to the osmotic and cation toxicities of NaCl, and the underlying relative capabilities for osmolyte synthesis and cation transport, are modulated by the general catabolite control exerted by glucose. PMID:9141675

Garca, M J; Ros, G; Ali, R; Bells, J M; Serrano, R

1997-04-01

267

Saccharomyces cerevisiae Oenococcus oeni interactions in wine: current knowledge and perspectives  

Microsoft Academic Search

Winemaking can be summarized as the biotransformation of must into wine, which is performed principally by Saccharomyces cerevisiae strains during the primary or alcoholic fermentation. A secondary fermentation, the so-called malolactic fermentation (MLF) is a biodeacidification that is often encouraged, since it improves wine stability and quality. Malolactic fermentation usually occurs either spontaneously or after inoculation with selected bacteria after

Herv Alexandre; Peter J. Costello; Fabienne Remize; Jean Guzzo; Michle Guilloux-Benatier

2004-01-01

268

EMPLEO DE FRACCIONES CELULARES DE LA LEVADURA Saccharomyces cerevisiae COMO ADITIVO ALIMENTARIO PARA Artemia franciscana  

Microsoft Academic Search

RESUMEN En el presente estudio se evala la levadura Saccharomyces cerevisiae de forma desintegrada (LD) y tres fracciones celulares obtenidas de ella: complejo pared-membrana (FP), ncleo-protenas (FN) y citoplasma (FC) como aditivo alimentario utilizando al crustceo Artemia franciscana como modelo de experimentacin. Se realizaron dos bioensayos para determinar el efecto que ejercan dichos aditivos en el crecimiento, biomasa seca, supervivencia

Yamil Comabella; Tsai Garca-Galano; Olimpia Carrillo; Yadir Mauri

269

Identification of Genes Required for Normal Pheromone-Induced Cell ~ Polarization in Saccharomyces cerevisiae  

Microsoft Academic Search

ABSTRACT In response to mating pheromones, cells of the yeast Saccharomyces cerevisiae adopt a polarized shmoo morphology, in which the cytoskeleton and proteins involved in mating are localized to a cell- surface projection. This polarization , yet to be determined. We discuss the possible roles of these gene products in establishing cell polarity during mating. M ANY cell types generate

Janet Chenevert; Nicole Val; Ira Herskowitz

270

Immobilization of Saccharomyces cerevisiae Cystathionine ?-Lyase and Application of the Product to Cystathionine Synthesis  

PubMed Central

Cystathionine ?-lyase of Saccharomyces cerevisiae was immobilized to aminohexyl-Sepharose through the cofactor pyridoxal 5?-phosphate and was characterized with respect to its cystathionine ?-synthase activity. The immobilized product was so stable that it repeatedly catalyzed as many as five cycles of the reaction without losing activity.

Yamagata, Shuzo; Akamatsu, Tsuyoshi; Iwama, Tomonori

2004-01-01

271

Toward a Comprehensive Atlas of the Physical Interactome of Saccharomyces cerevisiae  

Microsoft Academic Search

Defining protein complexes is critical to virtually all as- pects of cell biology. Two recent affinity purification\\/mass spectrometry studies in Saccharomyces cerevisiae have vastly increased the available protein interaction data. The practical utility of such high throughput interaction sets, however, is substantially decreased by the presence of false positives. Here we created a novel probabilistic metric that takes advantage of

Sean R. Collins; Patrick Kemmeren; Xue-Chu Zhao; Jack F. Greenblatt; Forrest Spencer; Frank C. P. Holstege; Jonathan S. Weissman; N. J. Krogan

2006-01-01

272

Unwinding RNA in Saccharomyces cerevisiae: DEAD-box proteins and related families  

Microsoft Academic Search

Members of the RNA-helicase family are defined by several evolutionary conserved motifs. They are found in all organisms from bacteria to humans and many viruses. The minimum number of RNA helicases present within a eukaryotic cell can be predicted from the complete sequence of the Saccharomyces cerevisiae genome. Recent progress in the functional analysis of various family members

Jess de la Cruz; Dieter Kressler; Patrick Linder

1999-01-01

273

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

274

Ethanol-Independent Biofilm Formation by a Flor Wine Yeast Strain of Saccharomyces cerevisiae?  

PubMed Central

Flor strains of Saccharomyces cerevisiae form a biofilm on the surface of wine at the end of fermentation, when sugar is depleted and growth on ethanol becomes dependent on oxygen. Here, we report greater biofilm formation on glycerol and ethyl acetate and inconsistent formation on succinic, lactic, and acetic acids.

Zara, Severino; Gross, Michael K.; Zara, Giacomo; Budroni, Marilena; Bakalinsky, Alan T.

2010-01-01

275

Copper-induced oxidative stress in Saccharomyces cerevisiae targets enzymes of the glycolytic pathway  

Microsoft Academic Search

Increased cellular levels of reactive oxygen species are known to arise during exposure of organisms to elevated metal concentrations, but the consequences for cells in the context of metal toxicity are poorly characterized. Using two-dimensional gel electrophoresis, combined with immunodetection of protein carbonyls, we report here that exposure of the yeast Saccharomyces cerevisiae to copper causes a marked increase in

Anupama Shanmuganathan; Simon V. Avery; Sylvia A. Willetts; John E. Houghton

2004-01-01

276

One-hybrid screens at the Saccharomyces cerevisiae HMR locus identify novel transcriptional silencing factors.  

PubMed Central

In Saccharomyces cerevisiae, genes located at the telomeres and the HM loci are subject to transcriptional silencing. Here, we report results of screening a Gal4 DNA-binding domain hybrid library for proteins that cause silencing when targeted to a silencer-defective HMR locus.

Andrulis, Erik D; Zappulla, David C; Alexieva-Botcheva, Krassimira; Evangelista, Carlos; Sternglanz, Rolf

2004-01-01

277

Microtubule Dynamics from Mating through the First Zygotic Division in the Budding Yeast Saccharomyces cerevisiae  

Microsoft Academic Search

We have used time-lapse digital imaging mi- croscopy to examine cytoplasmic astral microtubules (Mts) and spindle dynamics during the mating pathway in budding yeast Saccharomyces cerevisiae . Mating be- gins when two cells of opposite mating type come into proximity. The cells arrest in the G1 phase of the cell cy- cle and grow a projection towards one another forming

Paul Maddox; E. Chin; A. Mallavarapu; E. Yeh; E. D. Salmon; K. Bloom

1999-01-01

278

A new nomenclature for the cytoplasmic ribosomal proteins of Saccharomyces cerevisiae.  

PubMed Central

The availability of the complete sequence of the Saccharomyces cerevisiae genome has allowed a comprehensive analysis of the genes encoding cytoplasmic ribosomal proteins in this organism. On the basis of this complete inventory a new nomenclature for the yeast ribosomal proteins is presented.

Mager, W H; Planta, R J; Ballesta, J G; Lee, J C; Mizuta, K; Suzuki, K; Warner, J R; Woolford, J

1997-01-01

279

Telomeres and P-element of Drosophila melanogaster contain sequences that replicate autonomously in Saccharomyces cerevisiae  

Microsoft Academic Search

We have isolated restriction fragments from a shotgun collection of Drosophila DNA which function as autonomously replicating sequences (ARS) in Saccharomyces cerevisiae and hybridize with telomeric regions of the 2L, 2R, 4, and X chromosomes. In an independently obtained set of D. melanogaster clones five fragments hybridize in situ with telomeres and a number of internal sites. Two of them

O. N. Danilevskaya; E. V. Kurenova; B. A. Leibovitch; A. Ya. Shevelev; I. A. Bass; R. B. Khesin

1984-01-01

280

A Saccharomyces cerevisiae Genome-Wide Mutant Screen for Altered Sensitivity to K1 Killer Toxin  

Microsoft Academic Search

Using the set of Saccharomyces cerevisiae mutants individually deleted for 5718 yeast genes, we screened for altered sensitivity to the antifungal protein, K1 killer toxin, that binds to a cell wall -glucan receptor and subsequently forms lethal pores in the plasma membrane. Mutations in 268 genes, including 42 in genes of unknown function, had a phenotype, often mild, with 186

Nicolas Page ; Manon Gerard-Vincent; Patrice Menard; Maude Beaulieu; Masayuki Azuma; Gerrit J. P. Dijkgraaf; Thuy Nguyen; Tim Dowse; Anne-Marie Sdicu; Howard Bussey

281

Purification and Characterization of Extracellular and Intracellular Killer Toxin of Saccharomyces cerevisiae Strain 28  

Microsoft Academic Search

The extracellular killer toxin of Saccharomyces cerevisiae strain 28 was concentrated by ultrafiltration of culture supernatants and purified by ion-exchange chromatography. Polyacrylamide gradient gel electrophoresis in SDS indicated that the toxin is a glycoprotein with a molecular weight of about 16000. Amino acid analysis revealed that the killer toxin contains 11 1 amino acid residues, equivalent to a molecular weight

P. Pfeiffer; F. Radler

1982-01-01

282

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 Sndergaard; Lars K Poulsen

2010-01-01

283

Genomic Exploration of the Hemiascomycetous Yeasts: 20. Evolution of gene redundancy compared to Saccharomyces cerevisiae  

Microsoft Academic Search

We have evaluated the degree of gene redundancy in the nuclear genomes of 13 hemiascomycetous yeast species. Saccharomyces cerevisiae singletons and gene families appear generally conserved in these species as singletons and families of similar size, respectively. Variations of the number of homologues with respect to that expected affect from 7 to less than 24% of each genome. Since S.

Bertrand Llorente; Pascal Durrens; Alain Malpertuy; Michel Aigle; Franois Artiguenave; Galle Blandin; Monique Bolotin-Fukuhara; Elisabeth Bon; Philippe Brottier; Serge Casaregola; Bernard Dujon; Jacky de Montigny; Andre Lpingle; Ccile Neuvglise; Odile Ozier-Kalogeropoulos; Serge Potier; William Saurin; Fredj Tekaia; Claire Toffano-Nioche; Micheline Wsolowski-Louvel; Patrick Wincker; Jean Weissenbach; Jean-Luc Souciet; Claude Gaillardin

2000-01-01

284

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

285

Potentiation of gene targeting in human cells by expression of Saccharomyces cerevisiae Rad52  

Microsoft Academic Search

When exogenous DNA is stably introduced in mammalian cells, it is typically integrated in random positions, and only a minor fraction enters a pathway of homologous recombination (HR). The complex Rad51\\/Rad52 is a major player in the management of exogenous DNA in eukaryotic organisms and plays a critical role in the choice of repair system. In Saccharomyces cerevisiae, the pathway

Cristina Di Primio; Alvaro Galli; Tiziana Cervelli; Monica Zoppe; Giuseppe Rainaldi

2005-01-01

286

Mitotic Role for the Cdc28 Protein Kinase of Saccharomyces cerevisiae  

Microsoft Academic Search

The Cdc28 protein kinase functions in the G_1 to S phase transition of the cell cycle of the budding yeast Saccharomyces cerevisiae. This is in contrast with observations of the homologous protein kinase from a variety of metazoans, where activity and function are associated with the G_2 to M phase transition. We present evidence that the Cdc28 protein kinase is

Steven I. Reed; Curt Wittenberg

1990-01-01

287

Suppression of mitochondrially-determined resistance to chloramphenicol and paromomycin by nuclear genes in Saccharomyces cerevisiae  

Microsoft Academic Search

Phenotypic revertants of a drug resistant strain of Saccharomyces cerevisiae were induced by mutgenesis with manganese. Several of these drug sensitive mutants have been shown to result from mutations in the nuclear genome that cause phenotypic modification (suppression) of the mitochondrially-determined drug resistant genotype.

Michael F. Waxman; Jeffrey A. Knight; Philip S. Perlman

1979-01-01

288

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

289

Comparative genetics of yeasts: A novel ?-fructosidase gene SUC8 in Saccharomyces cerevisiae  

Microsoft Academic Search

Molecular and genetic analyses revealed that the distillers race XII, which is an ancestor of Saccharomyces cerevisiae Peterhof and Gatchina genetic lines, has three polymeric ?-fructosidase genes: SUC2, SUC5, and SUC8. The latter gene located on the X chromosome was identitied in this work for the first time. The presence of the single SUC2 gene in yeasts used in the

G. I. Naumov; E. S. Naumova

2010-01-01

290

Action of "colonie lisse" mutation on cell morphology of Saccharomyces cerevisiae.  

PubMed

The mutation of one of the genes of the series PLi in Saccharomyces cerevisiae Hansen brings about a reduction in the size of the cells. Besides, the mutation of some genes (PLi 5 and PLi 7) induces a change in the scanning microscopy appearance of the cell wall. PMID:1106823

Bizeau, C; Belin, J M; Galzy, P

1975-09-01

291

A comparison of clinical and food Saccharomyces cerevisiae isolates on the basis of potential virulence factors  

Microsoft Academic Search

Saccharomyces cerevisiae is the most widely used yeast in industrial\\/commercial food and beverage production and is even consumed as a nutritional supplement. Various cases of fungemia caused by this yeast species in severely debilitated traumatized or immune-deficient patients have been reported in recent years, suggesting that this species could be an opportunistic pathogen in such patients. To determine whether the

Rosa de Llanos; M. Teresa Fernndez-Espinar; Amparo Querol

2006-01-01

292

A Genetic Study of Signaling Processes for Repression of PHO5 Transcription in Saccharomyces cerevisiae  

Microsoft Academic Search

In the yeast Saccharomyces cerevisiae, transcription of a secreted acid phosphatase, PHO5, is repressed in response to high concentrations of extracellular inorganic phosphate. To investigate the signal transduction pathway leading to transcriptional regulation of PHO5, we carried out a genetic selection for mutants that express PHO5 constitutively. We then screened for mutants whose phenotypes are also dependent on the function

T. Walter Lau; Ken R. Schneider; Erin K. O'Shea

293

HOCl-mediated cell death and metabolic dysfunction in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

The nature of oxidative damage to Saccharomyces cerevisiae caused by levels of HOCl that inhibit cell replication was explored with the intent of identifying the loci of lethal lesions. Functions of cytosolic enzymes and organelles that are highly sensitive to inactivation by HOCl, including aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the mitochondrion, were only marginally affected by exposure of the yeast

David A King; Diane M Hannum; Jian-Shen Qi; James K Hurst

2004-01-01

294

In silico aided metabolic engineering of Saccharomyces cerevisiae for improved bioethanol production  

Microsoft Academic Search

In silico genome-scale cell models are promising tools for accelerating the design of cells with improved and desired properties. We demonstrated this by using a genome-scale reconstructed metabolic network of Saccharomyces cerevisiae to score a number of strategies for metabolic engineering of the redox metabolism that will lead to decreased glycerol and increased ethanol yields on glucose under anaerobic conditions.

Christoffer Bro; Birgitte Regenberg; Jochen Frster; Jens Nielsen

2006-01-01

295

Evolutionary engineering of mixed-sugar utilization by a xylose-fermenting Saccharomyces cerevisiae strain  

Microsoft Academic Search

We have recently reported about a Saccharomyces cerevisiae strain that, in addition to the Piromyces XylA xylose isomerase gene, overexpresses the native genes for the conversion of xylulose to glycolytic intermediates. This engineered strain (RWB 217) exhibited unprecedentedly high specific growth rates and ethanol production rates under anaerobic conditions with xylose as the sole carbon source. However, when RWB 217

Marko Kuyper; Maurice J. Toirkens; Jasper A. Diderich; Aaron A. Winkler; Johannes P. van Dijken; Jack T. Pronk

2005-01-01

296

Engineering the Pentose Phosphate Pathway of Saccharomyces Cerevisiae for Production of Ethanol and Xylitol.  

National Technical Information Service (NTIS)

The baker's yeast Saccharomyces cerevisiae has a long tradition in alcohol production from D-glucose of e.g. starch. However, without genetic modifications it is unable to utilize the 5-carbon sugars D-xylose and L-arabinose present in plant iomass. In th...

M. Toivari

2009-01-01

297

Metabolic engineering of a xylose-isomerase-expressing Saccharomyces cerevisiae strain for rapid anaerobic xylose fermentation  

Microsoft Academic Search

After an extensive selection procedure, Saccharomyces cerevisiae strains that express the xylose isomerase gene from the fungus Piromyces sp. E2 can grow anaerobically on xylose with a ?max of 0.03 h?1. In order to investigate whether reactions downstream of the isomerase control the rate of xylose consumption, we overexpressed structural genes for all enzymes involved in the conversion of xylulose

Marko Kuyper; Miranda M. P. Hartog; Maurice J. Toirkens; Marinka J. H. Almering; Aaron A. Winkler; Johannes P. van Dijken; Jack T. Pronk

2005-01-01

298

Influence of magnesium ions on heat shock and ethanol stress responses of Saccharomyces cerevisiae  

Microsoft Academic Search

This study has highlighted the role of magnesium ions in the amelioration of the detrimental effects of ethanol toxicity and temperature shock in a winemaking strain of Saccharomyces cerevisiae. Specifically, results based on measurements of cellular viability and heat shock protein synthesis together with scanning electron microscopy have shown that, by increasing the bioavailability of magnesium ions, physiological protection is

Rosslyn M. Birch; Graeme M. Walker

2000-01-01

299

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.

Berry, D; Volz, P A

1979-01-01

300

Mechanisms of mitochondrial DNA escape to the nucleus in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

The transfer of organelle nucleic acid to the nucleus has been observed in both plants and animals. Using a unique assay\\u000a to monitor mitochondrial DNA escape to the nucleus in the yeast Saccharomyces cerevisiae, we previously showed that mutations in several nuclear genes, collectively called yme mutants, cause a high rate of mitochondrial DNA escape to the nucleus. Here we

Karen S. Shafer; Theodor Hanekamp; Karen H. White; Peter E. Thorsness

1999-01-01

301

A genome-wide deletion mutant screen identifies pathways affected by nickel sulfate in Saccharomyces cerevisiae  

Microsoft Academic Search

BACKGROUND: The understanding of the biological function, regulation, and cellular interactions of the yeast genome and proteome, along with the high conservation in gene function found between yeast genes and their human homologues, has allowed for Saccharomyces cerevisiae to be used as a model organism to deduce biological processes in human cells. Here, we have completed a systematic screen of

Adriana Arita; Xue Zhou; Thomas P Ellen; Xin Liu; Jingxiang Bai; John P Rooney; Adrienne Kurtz; Catherine B Klein; Wei Dai; Thomas J Begley; Max Costa

2009-01-01

302

How heterologously expressed Escherichia coli genes contribute to understanding DNA repair processes in Saccharomyces cerevisiae  

Microsoft Academic Search

DNA-damaging agents constantly challenge cellular DNA; and efficient DNA repair is therefore essential to maintain genome stability and cell viability. Several DNA repair mechanisms have evolved and these have been shown to be highly conserved from bacteria to man. DNA repair studies were originally initiated in very simple organisms such as Escherichia coli and Saccharomyces cerevisiae, bacteria being the best

Jela Brozmanov; Viera Vl?kov; Miroslav Chovanec

2004-01-01

303

Engineering topology and kinetics of sucrose metabolism in Saccharomyces cerevisiae for improved ethanol yield  

Microsoft Academic Search

Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-proton symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and

Thiago O. Basso; Stefan de Kok; Marcelo Dario; Jlio Czar A. do Espirito-Santo; Gabriela Mller; Paulo S. Schllg; Carlos P. Silva; Aldo Tonso; Jean-Marc Daran; Andreas K. Gombert; Antonius J. A. van Maris; Jack T. Pronk; Boris U. Stambuk

2011-01-01

304

Effect of Saccharomyces cerevisiae or Aspergillus oryzae cultures and NDF level on parameters of ruminal fermentation  

Microsoft Academic Search

A metabolism trial was conducted to study the effect of two direct-fed microbial cultures (Saccharomyces cerevisiae, SC; Aspergillus oryzae, AO) and neutral detergent fibre (NDF) level on ruminal fermentation. Six ruminally fistulated Holstein heifers (300 kg body weight) were randomly assigned to a 6 6 Latin square where treatments were control groups (CG) at two NDF levels (27 and

R. L. A. Miranda; M. G. D. Mendoza; J. R. Brcena-Gama; M. S. S. Gonzlez; R. Ferrara; C. M. E. Ortega; P. M. A. Cobos

1996-01-01

305

Do mitochondria regulate the heat-shock response in Saccharomyces cerevisiae ?  

Microsoft Academic Search

A mild heat shock induces the synthesis of heat-shock proteins (hsps), which protect cells from damage during more extreme heat exposure. The nature of the signals that induce transcription of heat shock-regulated genes remains conjectural. In this work we studied the role of mitochondria in regulating hsps synthesis in Saccharomyces cerevisiae. The results obtained clearly indicate that a mild heat

Eugene G. Rikhvanov; Nina N. Varakina; Tatyana M. Rusaleva; Elena I. Rachenko; Dmitry A. Knorre; Victor K. Voinikov

2005-01-01

306

Cytotoxicity and gene induction by some essential oils in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

In order to get an insight into the possible genotoxicity of essential oils (EOs) used in traditional pharmacological applications we tested five different oils extracted from the medicinal plants Origanum compactum, Coriandrum sativum, Artemisia herba alba, Cinnamomum camphora (Ravintsara aromatica) and Helichrysum italicum (Calendula officinalis) for genotoxic effects using the yeast Saccharomyces cerevisiae. Clear cytotoxic effects were observed in the

F. Bakkali; S. Averbeck; D. Averbeck; A. Zhiri; M. Idaomar

2005-01-01

307

Cell-recycle batch fermentation using immobilized cells of flocculent Saccharomyces cerevisiae wine strains  

Microsoft Academic Search

Five, highly flocculeng strains of Saccharomyces cerevisiae, isolated from wine, were immobilized in calcium alginate beads to optimize primary must fermentation. Three cell-recycle batch fermentations (CRBF) of grape musts were performed with the biocatalyst and the results compared with those obtained with free cells. During the CRBF process, the entrapped strains showed some variability in the formation of secondary products

G. Suzzi; P. Romano; L. Vannini; L. Turbanti; P. Domizio

1996-01-01

308

Relationship of codon bias to mRNA concentration and protein length inSaccharomyces cerevisiae  

Microsoft Academic Search

In 1982, Ikemura reported a strikingly unequal usage of different synonymous codons, in five Saccharomyces cerevisiae nuclear genes having high protein levels. To study this trend in detail, we examined data from three independent studies that used oligonucleotide arrays or SAGE to estimate mRNA concentrations for nearly all genes in the genome. Correlation coefficients were calculated for the relationship of

Avril Coghlan; Kenneth H. Wolfe

2000-01-01

309

An insertion mutation associated with constitutive expression of repressible acid phosphatase in Saccharomyces cerevisiae  

Microsoft Academic Search

The PHO83 mutation in Saccharomyces cerevisiae, which had been detected on the basis of constitutive production of repressible acid phosphatase and mapped at the end of the PHO5 locus, was analysed by Southern hybridization with cloned DNA fragments of the PHO5 gene as probe. It was shown that this mutant has a DNA insertion of about 6 kilobase pairs, probably

Akio Toh-e; Yoshinobu Kaneko; Jir Akimaru; Yasuji Oshima

1983-01-01

310

Replication and transcription of human papillomavirus type 58 genome in Saccharomyces cerevisiae  

Microsoft Academic Search

BACKGROUND: To establish a convenient system for the study of human papillomavirus (HPV), we inserted a Saccharomyces cerevisiae selectable marker, Ura, into HPV58 genome and transformed it into yeast. RESULTS: HPV58 genome could replicate extrachromosomally in yeast, with transcription of its early and late genes. However, with mutation of the viral E2 gene, HPV58 genome lost its mitotic stability, and

Jing Li; Xiao Wang; Juan Liu; Hong Wang; Xiao-Li Zhang; Wei Tang; Yun-Dong Sun; Xin Wang; Xiu-Ping Yu; Wei-Ming Zhao

2010-01-01

311

Cofermentation of cellobiose and galactose by an engineered Saccharomyces cerevisiae strain.  

PubMed

We demonstrate improved ethanol yield and productivity through cofermentation of cellobiose and galactose by an engineered Saccharomyces cerevisiae strain expressing genes coding for cellodextrin transporter (cdt-1) and intracellular ?-glucosidase (gh1-1) from Neurospora crassa. Simultaneous fermentation of cellobiose and galactose can be applied to producing biofuels from hydrolysates of marine plant biomass. PMID:21705527

Ha, Suk-Jin; Wei, Qiaosi; Kim, Soo Rin; Galazka, Jonathan M; Cate, Jamie H D; Cate, Jamie; Jin, Yong-Su

2011-08-15

312

Saccharomyces cerevisiae JEN1 Promoter Activity Is Inversely Related to Concentration of Repressing Sugar  

Microsoft Academic Search

When carbon sources are changed, Saccharomyces cerevisiae transcriptional patterns drastically change. To identify genes whose transcription can be used to quantitatively measure sugar concentrations, we searched genomic expression databases for a set of genes that are highly induced during the diauxic shift, and we used the promoters from these genes to drive expression of green fluorescent protein (GFP). Certain sugars,

Prima Chambers; Aminatu Issaka; Sean P. Palecek

2004-01-01

313

Targeted protein depletion in Saccharomyces cerevisiae by activation of a bidirectional degron  

Microsoft Academic Search

BACKGROUND: Tools for in vivo manipulation of protein abundance or activity are highly beneficial for life science research. Protein stability can be efficiently controlled by conditional degrons, which induce target protein degradation at restrictive conditions. RESULTS: We used the yeast Saccharomyces cerevisiae for development of a conditional, bidirectional degron to control protein stability, which can be fused to the target

Marc Jungbluth; Christian Renicke; Christof Taxis

2010-01-01

314

Genome-wide association analysis of clinical vs. nonclinical origin provides insights into Saccharomyces cerevisiae pathogenesis.  

PubMed

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 occurred 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 vs. nonclinical origin in S. cerevisiae. Using tiling array-based, high-density genotypes of 44 clinical and 44 nonclinical 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, L A H; Lucas, J E; Georgianna, D R; McCusker, J H

2011-10-01

315

Expression of native and mutant extracellular lipases fromYarrowia lipolytica in Saccharomyces cerevisiae  

PubMed Central

Summary Saccharomyces cerevisiae cannot produce extracellular lipase and utilize low?cost lipid substrates. This study aimed to express extracellular lipase from Yarrowia lipolytica in S.?cerevisiae, construct recombinant oily substrate consumer strains, and compare the roles of native and mutant Y.?lipolytica extracellular lipases in S.?cerevisiae. The LIP2 gene of Y.?lipolytica DSM3286 and its mutant Y.?lipolytica U6 were isolated and cloned by expression vector in S.?cerevisiae. New recombinant S.?cerevisiae strains FDS100 containing the native LIP2 gene, and FDS101 containing the mutant LIP2 gene were produced 10 and 15?U?ml ?1 extracellular lipase respectively, on a production medium containing olive oil. New recombinant S.?cerevisiae strains produce acceptable amount of extracellular lipase in comparison with Y.?lipolytica wild?type strains. These strains can utilize olive oil and lipids as low?cost substrates to produce bioethanol, single cell protein and other biotechnologically valuable products. The recombinant S.?cerevisiae strain with mutant LIP2 produced lipase with 1.5?fold higher activity. The LIP2 gene of Y.?lipolytica was expressed in S.?cerevisiae as a heterologous protein without any modifications. Strong components of the Y.?lipolytica expression/secretion system could be used for high?level production of recombinant proteins in S.?cerevisiae.

Darvishi, Farshad

2012-01-01

316

Crystal structure of Saccharomyces cerevisiae 6-phosphogluconate dehydrogenase Gnd1  

PubMed Central

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

He, Weiwei; Wang, Yi; Liu, Wei; Zhou, Cong-Zhao

2007-01-01

317

Overall kinetic mechanism of saccharopine dehydrogenase from Saccharomyces cerevisiae.  

PubMed

Kinetic data have been measured for the histidine-tagged saccharopine dehydrogenase from Saccharomyces cerevisiae, suggesting the ordered addition of nicotinamide adenine dinucleotide (NAD) followed by saccharopine in the physiologic reaction direction. In the opposite direction, the reduced nicotinamide adenine dinucleotide (NADH) adds to the enzyme first, while there is no preference for the order of binding of alpha-ketoglutarate (alpha-Kg) and lysine. In the direction of saccharopine formation, data also suggest that, at high concentrations, lysine inhibits the reaction by binding to free enzyme. In addition, uncompetitive substrate inhibition by alpha-Kg and double inhibition by NAD and alpha-Kg suggest the existence of an abortive E:NAD:alpha-Kg complex. Product inhibition by saccharopine is uncompetitive versus NADH, suggesting a practical irreversibility of the reaction at pH 7.0 in agreement with the overall K(eq). Saccharopine is noncompetitive versus lysine or alpha-Kg, suggesting the existence of both E:NADH:saccharopine and E:NAD:saccharopine complexes. NAD is competitive versus NADH, and noncompetitive versus lysine and alpha-Kg, indicating the combination of the dinucleotides with free enzyme. Dead-end inhibition studies are also consistent with the random addition of alpha-Kg and lysine. Leucine and oxalylglycine serve as lysine and alpha-Kg dead-end analogues, respectively, and are uncompetitive against NADH and noncompetitive against alpha-Kg and lysine, respectively. Oxaloacetate (OAA), pyruvate, and glutarate behave as dead-end analogues of lysine, which suggests that the lysine-binding site has a higher affinity for keto acid analogues than does the alpha-Kg site or that dicarboxylic acids have more than one binding mode on the enzyme. In addition, OAA and glutarate also bind to free enzyme as does lysine at high concentrations. Glutarate gives S-parabolic noncompetitive inhibition versus NADH, indicating the formation of a E:(glutarate)2 complex as a result of occupying both the lysine- and alpha-Kg-binding sites. Pyruvate, a slow alternative keto acid substrate, exhibits competitive inhibition versus both lysine and alpha-Kg, suggesting the combination to the E:NADH:alpha-Kg and E:NADH:lysine enzyme forms. The equilibrium constant for the reaction has been measured at pH 7.0 as 3.9 x 10(-7) M by monitoring the change in NADH upon the addition of the enzyme. The Haldane relationship is in very good agreement with the directly measured value. PMID:17002315

Xu, Hengyu; West, Ann H; Cook, Paul F

2006-10-01

318

The yeast dynein Dyn2-Pac11 complex is a dynein dimerization/processivity factor: structural and single-molecule characterization  

PubMed Central

Cytoplasmic dynein is the major microtubule minus enddirected motor. Although studies have probed the mechanism of the C-terminal motor domain, if and how dynein's N-terminal tail and the accessory chains it binds regulate motor activity remain to be determined. Here, we investigate the structure and function of the Saccharomyces cerevisiae dynein light (Dyn2) and intermediate (Pac11) chains in dynein heavy chain (Dyn1) movement. We present the crystal structure of a Dyn2-Pac11 complex, showing Dyn2-mediated Pac11 dimerization. To determine the molecular effects of Dyn2 and Pac11 on Dyn1 function, we generated dyn2? and dyn2?pac11? strains and analyzed Dyn1 single-molecule motor activity. We find that the Dyn2-Pac11 complex promotes Dyn1 homodimerization and potentiates processivity. The absence of Dyn2 and Pac11 yields motors with decreased velocity, dramatically reduced processivity, increased monomerization, aggregation, and immobility as determined by single-molecule measurements. Deleting dyn2 significantly reduces Pac11-Dyn1 complex formation, yielding Dyn1 motors with activity similar to Dyn1 from the dyn2?pac11? strain. Of interest, motor phenotypes resulting from Dyn2-Pac11 complex depletion bear similarity to a point mutation in the mammalian dynein N-terminal tail (Loa), highlighting this region as a conserved, regulatory motor element.

Rao, Lu; Romes, Erin M.; Nicholas, Matthew P.; Brenner, Sibylle; Tripathy, Ashutosh; Gennerich, Arne; Slep, Kevin C.

2013-01-01

319

Outlining a future for non-Saccharomyces yeasts: selection of putative spoilage wine strains to be used in association with Saccharomyces cerevisiae for grape juice fermentation.  

PubMed

The use of non-Saccharomyces yeasts that are generally considered as spoilage yeasts, in association with Saccharomyces cerevisiae for grape must fermentation was here evaluated. Analysis of the main oenological characteristics of pure cultures of 55 yeasts belonging to the genera Hanseniaspora, Pichia, Saccharomycodes and Zygosaccharomyces revealed wide biodiversity within each genus. Moreover, many of these non-Saccharomyces strains had interesting oenological properties in terms of fermentation purity, and ethanol and secondary metabolite production. The use of four non-Saccharomyces yeasts (one per genus) in mixed cultures with a commercial S. cerevisiae strain at different S. cerevisiae/non-Saccharomyces inoculum ratios was investigated. This revealed that most of the compounds normally produced at high concentrations by pure cultures of non-Saccharomyces, and which are considered detrimental to wine quality, do not reach threshold taste levels in these mixed fermentations. On the other hand, the analytical profiles of the wines produced by these mixed cultures indicated that depending on the yeast species and the S. cerevisiae/non-Saccharomyces inoculum ratio, these non-Saccharomyces yeasts can be used to increase production of polysaccharides and to modulate the final concentrations of acetic acid and volatile compounds, such as ethyl acetate, phenyl-ethyl acetate, 2-phenyl ethanol, and 2-methyl 1-butanol. PMID:21531033

Domizio, Paola; Romani, Cristina; Lencioni, Livio; Comitini, Francesca; Gobbi, Mirko; Mannazzu, Ilaria; Ciani, Maurizio

2011-06-30

320

Interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in wine fermentation: influence of inoculation and nitrogen content.  

PubMed

Alcoholic fermentation by an oenological strain of Torulaspora delbrueckii in association with an oenological strain of Saccharomyces cerevisiae was studied in mixed and sequential cultures. Experiments were performed in a synthetic grape must medium in a membrane bioreactor, a special tool designed to study indirect interactions between microorganisms. Results showed that the S. cerevisiae strain had a negative impact on the T. delbrueckii strain, leading to a viability decrease as soon as S. cerevisiae was inoculated. Even for high inoculation of T. delbrueckii (more than 20 S. cerevisiae) in mixed cultures, T. delbrueckii growth was inhibited. Substrate competition and cell-to-cell contact mechanism could be eliminated as explanations of the observed interaction, which was probably an inhibition by a metabolite produced by S. cerevisiae. S. cerevisiae should be inoculated 48h after T. delbrueckii in order to ensure the growth of T. delbrueckii and consequently a decrease of volatile acidity and a higher isoamyl acetate production. In this case, in a medium with a high concentration of assimilable nitrogen (324mgL(-1)), S. cerevisiae growth was not affected by T. delbrueckii. But in a sequential fermentation in a medium containing 176mgL(-1) initial assimilable nitrogen, S. cerevisiae was not able to develop because of nitrogen exhaustion by T. delbrueckii growth during the first 48h, leading to sluggish fermentation. PMID:24500666

Taillandier, Patricia; Lai, Quoc Phong; Julien-Ortiz, Anne; Brandam, Cdric

2014-07-01

321

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 30C. 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.

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

2002-01-01

322

Disruption of the 'Saccharomyces cerevisiae' Gene for NADPH-Cytochrome P450 Reductase Causes Increased Sensitivity to Ketoconazole.  

National Technical Information Service (NTIS)

Strains of Saccharomyces cerevisiae deleted in the NADPH-cytochrome P450 reductase gene by transplacement are 200-fold more sensitive to ketoconazole, an inhibitor of the cytochrome P450 lanosterol 14alpha-demethylase. Resistance is restored through compl...

T. R. Sutter J. C. Loper

1989-01-01

323

Microbial Cells as Biosorbents for Heavy Metals: Accumulation of Uranium by Saccharomyces cerevisiae and Pseudomonas aeruginosa  

PubMed Central

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

Strandberg, Gerald W.; Shumate, Starling E.; Parrott, John R.

1981-01-01

324

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

SciTech Connect

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

Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.

1981-01-01

325

Investigation of fatty acid accumulation in the engineered Saccharomyces cerevisiae under nitrogen limited culture condition.  

PubMed

In this study, the Saccharomyces cerevisiae wild type strain and engineered strain with an overexpressed heterologous ATP-citrate lyase (acl) were cultured in medium with different carbon and nitrogen concentrations, and their fatty acid production levels were investigated. The results showed that when the S. cerevisiae engineered strain was cultivated under nitrogen limited culture condition, the yield of mono-unsaturated fatty acids showed higher than that under non-nitrogen limited condition; with the carbon concentration increased, the accumulation become more apparent, whereas in the wild type strain, no such correlation was found. Besides, the citrate level in the S. cerevisiae under nitrogen limited condition was found to be much higher than that under non-nitrogen limited condition, which indicated a relationship between the diminution of nitrogen and accumulation of citrate in the S. cerevisiae. The accumulated citrate could be further cleaved by acl to provide substrate for fatty acid synthesis. PMID:24755317

Tang, Xiaoling; Chen, Wei Ning

2014-06-01

326

Genetic and molecular mapping of the pma1 mutation conferring vanadate resistance to the plasma membrane ATPase from Saccharomyces cerevisiae  

Microsoft Academic Search

In the yeast Saccharomyces cerevisiae, the pma1 mutations confers vanadate-resistance to H+-ATPase activity when measured in isolated plasma membranes. In vivo, the growth of pma1 mutants is resistant to Dio-9, ethidium bromide and guanidine derivatives. This phenotype was used to man the pma1 mutation adjacent to LEU1 gene on chromosome VII. From a cosmid library of a wild-type Saccharomyces cerevisiae

Stanislaw Ulaszewski; Elisabetta Balzi; Andr Goffeau

1987-01-01

327

Use of PMA1 as a Housekeeping Biomarker for Assessment of Toxicant-Induced Stress in Saccharomyces cerevisiae  

Microsoft Academic Search

The brewer's yeast Saccharomyces cerevisiae has emerged as a versatile and robust model system for laboratory use to study toxic effects of various substances. In this study, toxicant-induced stresses of pure compounds were investigated in Saccharomyces cerevisiae utilizing a destabilized version of the green fluores- cent protein optimized for expression in yeast (yEGFP3) under control of the promoter of the

Marcel Schmitt; Petra Schwanewilm; Jost Ludwig; Hella Lichtenberg-Frate

2006-01-01

328

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.

Hyma, Katie E.; Fay, Justin C.

2012-01-01

329

Fumaric acid production in Saccharomyces cerevisiae by in silico aided metabolic engineering.  

PubMed

Fumaric acid (FA) is a promising biomass-derived building-block chemical. Bio-based FA production from renewable feedstock is a promising and sustainable alternative to petroleum-based chemical synthesis. Here we report on FA production by direct fermentation using metabolically engineered Saccharomyces cerevisiae with the aid of in silico analysis of a genome-scale metabolic model. First, FUM1 was selected as the target gene on the basis of extensive literature mining. Flux balance analysis (FBA) revealed that FUM1 deletion can lead to FA production and slightly lower growth of S. cerevisiae. The engineered S. cerevisiae strain obtained by deleting FUM1 can produce FA up to a concentration of 61031 mg L(-1) without any apparent change in growth in fed-batch culture. FT-IR and (1)H and (13)C NMR spectra confirmed that FA was synthesized by the engineered S. cerevisiae strain. FBA identified pyruvate carboxylase as one of the factors limiting higher FA production. When the RoPYC gene was introduced, S. cerevisiae produced 113448 mg L(-1) FA. Furthermore, the final engineered S. cerevisiae strain was able to produce 167552 mg L(-1) FA in batch culture when the SFC1 gene encoding a succinate-fumarate transporter was introduced. These results demonstrate that the model shows great predictive capability for metabolic engineering. Moreover, FA production in S. cerevisiae can be efficiently developed with the aid of in silico metabolic engineering. PMID:23300594

Xu, Guoqiang; Zou, Wei; Chen, Xiulai; Xu, Nan; Liu, Liming; Chen, Jian

2012-01-01

330

Production of Extracellular and Total Invertase by Candida utilis, Saccharomyces cerevisiae, and Other Yeasts  

PubMed Central

Some strains of Candida utilis produce exceptionally large amounts of extracellular and total invertase. Strain Y-900 of C. utilis produces high yields whether the carbon source is sucrose, glucose, maltose, or xylose and still higher yields with lactic acid, glycerol, and ethyl alcohol. Approximately 20 to 30% of the total invertase of C. utilis is extracellular. Strains of Saccharomyces cerevisiae and Saccharomyces carlsbergensis are generally inferior to C. utilis in production of extracellular and total invertase, the difference being accentuated in shaken cultures. The industrial yeasts are generally superior in invertase production to the other yeasts included in the survey.

Dworschack, Robert G.; Wickerham, Lynferd J.

1961-01-01

331

Role of Saccharomyces cerevisiae serine O-acetyltransferase in cysteine biosynthesis  

Microsoft Academic Search

Some strains of Saccharomyces cerevisiae have detectable activities of L-serine O-acetyltransferase (SATase) and O-acetyl-L-serine\\/O-acetyl-L-homoserine sulfhydrylase (OAS\\/OAH-SHLase), but synthesize L-cysteine exclusively via cystathionine by cystathionine ?-synthase and cystathionine ?-lyase. To untangle this peculiar feature in sulfur metabolism, we introduced Escherichia coli genes encoding SATase and OAS-SHLase into S. cerevisiaeL-cysteine auxotrophs. While the cells expressing SATase grew on medium lacking L-cysteine, those

Hiroshi Takagi; Kenji Yoshioka; Naoki Awano; Shigeru Nakamori; Bun-ichiro Ono

2003-01-01

332

Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals.  

PubMed

Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology and the advances in yeast strain engineering will stimulate development of novel yeast-based processes for chemicals production. PMID:24677744

Borodina, Irina; Nielsen, Jens

2014-05-01

333

Automated Yeast Mating Protocol Using Open Reading Frames from Saccharomyces cerevisiae Genome to Improve Yeast Strains for Cellulosic Ethanol Production  

Microsoft Academic Search

Engineering the industrial ethanologen Saccharomyces cerevisiae to use pentose sugars from lignocellulosic biomass is critical for commercializing cellulosic fuel ethanol production. Approaches to engineer pentose-fermenting yeasts have required expression of additional genes. We implemented a high-throughput strategy to improve anaerobic growth on xylose and rate of ethanol production by evaluating overexpression of each native S. cerevisiae gene from a collection

Stephen R. Hughes; Ronald E. Hector; Joseph O. Rich; Nasib Qureshi; Kenneth M. Bischoff; Bruce S. Dien; Badal C. Saha; Siqing Liu; Elby J. Cox; John S. Jackson Jr.; David E. Sterner; Tauseef R. Butt; Joshua LaBaer; Michael A. Cotta

2009-01-01

334

Application of response surface methodology for optimization of cadmium biosorption in an aqueous solution by Saccharomyces cerevisiae  

Microsoft Academic Search

Optimization of a cadmium biosorption process was performed by varying three independent parameters (initial pH, initial cadmium ion concentration, Saccharomyces cerevisiae dosage) using a central composite design (CCD) under response surface methodology (RSM). For the maximum biosorption of cadmium ion in an aqueous solution by S. cerevisiae, a total of 20 experimental runs were set and the experimental data fitted

Farshid Ghorbani; Habibollah Younesi; Seyed Mahmoud Ghasempouri; Ali Akbar Zinatizadeh; Mahlihe Amini; Ali Daneshi

2008-01-01

335

Genomic Exploration of the Hemiascomycetous Yeasts: 18. Comparative analysis of chromosome maps and synteny with Saccharomyces cerevisiae  

Microsoft Academic Search

We have analyzed the evolution of chromosome maps of Hemiascomycetes by comparing gene order and orientation of the 13 yeast species partially sequenced in this program with the genome map of Saccharomyces cerevisiae. From the analysis of nearly 8000 situations in which two distinct genes having homologs in S. cerevisiae could be identified on the sequenced inserts of another yeast

Bertrand Llorente; Alain Malpertuy; Ccile Neuvglise; Jacky de Montigny; Michel Aigle; Franois Artiguenave; Galle Blandin; Monique Bolotin-Fukuhara; Elisabeth Bon; Philippe Brottier; Serge Casaregola; Pascal Durrens; Claude Gaillardin; Andre Lpingle; Odile Ozier-Kalogropoulos; Serge Potier; William Saurin; Fredj Tekaia; Claire Toffano-Nioche; Micheline Wsolowski-Louvel; Patrick Wincker; Jean Weissenbach; Jean-Luc Souciet; Bernard Dujon

2000-01-01

336

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

Microsoft Academic Search

The Saccharomyces cerevisiae CDC3, CDCIO, CDCll, and CDC12 genes encode a family of related proteins, the septins, which are involved in cell division and the organization of the cell surface during vegetative growth. A search for additional S. cerevisiae septin genes using the polymerase chain reaction iden- tified SPR3, a gene that had been identified previously on the basis of

Hanna Fares; Loretta Goetsch; John R. Pringle

1996-01-01

337

Shear-flow induced detachment of Saccharomyces cerevisiae from stainless steel: Influence of yeast and solid surface properties  

Microsoft Academic Search

The present study focused on the shear-induced detachment of Saccharomyces cerevisiae in adhesive contact with a 316L stainless steel surface using a shear stress flow chamber, with a view to determining the respective influence of the yeast surface properties and the support characteristics. The effect of cultivation of S. cerevisiae yeast cells on their subsequent detachment from the solid surface

Galle Guillemot; Guadalupe Vaca-Medina; Helene Martin-Yken; Aude Vernhet; Philippe Schmitz; Muriel Mercier-Bonin

2006-01-01

338

Selected non- Saccharomyces wine yeasts in controlled multistarter fermentations with Saccharomyces cerevisiae  

Microsoft Academic Search

Non-Saccharomyces yeasts are metabolically active during spontaneous and inoculated must fermentations, and by producing a plethora of by-products, they can contribute to the definition of the wine aroma. Thus, use of Saccharomyces and non-Saccharomyces yeasts as mixed starter cultures for inoculation of wine fermentations is of increasing interest for quality enhancement and improved complexity of wines. We initially characterized 34

Francesca Comitini; Mirko Gobbi; Paola Domizio; Cristina Romani; Livio Lencioni; Ilaria Mannazzu; Maurizio Ciani

2011-01-01

339

Use of Saccharomyces cerevisiae immobilized in agarose gel as a binding agent for diffusive gradients in thin films  

Microsoft Academic Search

A new binding agent, consisting of the yeast Saccharomyces cerevisiae immobilized in agarose, is proposed for use in diffusive gradients in thin films (DGT). Different gel compositions, containing from 4.5% to 20% (m\\/v) of S. cerevisiae and 1.55.0% (m\\/v) of agarose, were prepared and tested for uptake of Cd(II). For gels containing 20% (m\\/v) of S. cerevisiae, a mass of

Amauri A. Menegrio; Paulo S. Tonello; Steven F. Durrant

340

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

341

Saccharomyces cerevisiae STR3 and yeast cystathionine ?-lyase enzymes: The potential for engineering increased flavor release.  

PubMed

Selected Saccharomyces cerevisiae strains are used for wine fermentation. Based on several criteria, winemakers often use a specific yeast to improve the flavor, mouth feel, decrease the alcohol content and desired phenolic content, just to name a few properties. Scientists at the AWRI previously illustrated the potential for increased flavor release from grape must via overexpression of the Escherichia coli Tryptophanase enzyme in wine yeast. To pursue a self-cloning approach for improving the aroma production, we recently characterized the S. cerevisiae cystathionine ?-lyase STR3, and investigated its flavor releasing capabilities. Here, we continue with a phylogenetic investigation of STR3 homologs from non-Saccharomyces yeasts to map the potential for using natural variation to engineer new strains. PMID:22572787

Holt, Sylvester; Cordente, Antonio G; Curtin, Chris

2012-01-01

342

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

343

Functional Expression of Spirulina -? 6 Desaturase Gene in Yeast, Saccharomyces cerevisiae  

Microsoft Academic Search

Spirulina-acyl-lipid desaturases are membrane-bound enzymes found in thylakoid and plasma membranes. These enzymes carry out the fatty acid desaturation process of Spirulina to yield ?-linolenic acid (GLA) as the final desaturation product. In this study, Spirulina-?6 desaturase encoded by the desD gene was heterologously expressed and characterized in Saccharomyces cerevisiae. We then conducted site-directed mutagenesis of the histidine residues in

Pavinee Kurdrid; Sanjukta Subudhi; Apiradee Hongsthong; Marasri Ruengjitchatchawalya; Morakot Tanticharoen

2005-01-01

344

Study of the production of fructose and ethanol from sucrose media by Saccharomyces cerevisiae  

Microsoft Academic Search

The production of ethanol and enriched fructose syrups from a synthetic medium with various sucrose concentrations using the mutant Saccharomyces cerevisiae ATCC 36858 was investigated. In batch tests, fructose yields were above 90% of theoretical values for the sucrose concentrations between 35 g\\/l and 257 g\\/l. The specific growth rates and biomass yields were from 0.218 to 0.128 h-1 and

H. Atiyeh; Z. Duvnjak

2001-01-01

345

The use of monochloroacetic acid for improved ethanol production by immobilized Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae adsorbed on acid-treated glass beads produced 5.4 g l ?1 ethanol at 96 h in batch process. Precoating the acid-treated glass beads with gelatin (25 g l ?1 ) before immobilization of the cells increased ethanol production to 26.3 g l ?1 at 72 h. Cell leakage into the medium was decreased when the immobilized cells were crosslinked

V. Arasaratnam; K. Balasubramaniam

1998-01-01

346

HSM2 ( HMO1) gene participates in mutagenesis control in yeast Saccharomyces cerevisiae  

Microsoft Academic Search

We have previously reported about a new Saccharomyces cerevisiae mutation, hsm2-1, that results in increase of both spontaneous and UV-induced mutation frequencies but does not alter UV-sensitivity. Now HSM2 gene has been genetically and physically mapped and identified as a gene previously characterized as HMO1, a yeast homologue of human high mobility group genes HMG1\\/2. We found that hsm2 mutant

S. Yu. Alekseev; S. V. Kovaltsova; I. V. Fedorova; L. M. Gracheva; T. A. Evstukhina; V. T. Peshekhonov; V. G. Korolev

2002-01-01

347

EFFECT OF GENES CONTROLLING RADIATION SENSITIVITY ON CHEMICALLY INDUCED MUTATIONS IN SACCHAROMYCES CEREVISIAE  

Microsoft Academic Search

The effect of 16 different genes (rad) conferring radiation sensitivity on chemically induced reversion in the yeast Saccharomyces cerevisiae was deter- mined. The site of reversion used was a well-defined chain initiation mutant mapping in the structural gene coding for iso-I-cytochrome c. High doses of EMS and HNO, resulted in decreased reversion of cyci-I31 in radb, rad9 and rad15 strains

LOUISE PRAKASH

348

L -ornithine transaminase synthesis in Saccharomyces cerevisiae : Regulation by inducer exclusion  

Microsoft Academic Search

The ornithine transaminase (EC.2.6.1.13) of Saccharomyces cerevisiae is induced by arginine, ornithine, and their analogs. Genetic regulatory elements which are involved in this induction process have been defined due to the isolation of specific mutants. Two classes of OTAse operator mutants have previously been described; three unlinked genes are presumed to code for a specific repressor, CARGR of both of

Jacqueline Deschamps; Evelyne Dubois; Jean-Marie Wiame

1979-01-01

349

Dependence of ORC Silencing Function on NatA-Mediated N Acetylation in Saccharomyces cerevisiae  

Microsoft Academic Search

N acetylation is one of the most abundant protein modifications in eukaryotes and is catalyzed by N- terminal acetyltransferases (NATs). NatA, the major NAT in Saccharomyces cerevisiae, consists of the subunits Nat1p, Ard1p, and Nat5p and is necessary for the assembly of repressive chromatin structures. Here, we found that Orc1p, the large subunit of the origin recognition complex (ORC), required

Antje Geissenhoner; Christoph Weise; Ann E. Ehrenhofer-Murray

2004-01-01

350

GCN5 Is a Positive Regulator of Origins of DNA Replication in Saccharomyces cerevisiae  

Microsoft Academic Search

GCN5 encodes one of the non-essential Histone Acetyl Transferases in Saccharomyces cerevisiae. Extensive evidence has indicated that GCN5 is a key regulator of gene expression and could also be involved in transcriptional elongation, DNA repair and centromere maintenance. Here we show that the deletion of GCN5 decreases the stability of mini-chromosomes; that the tethering of Gcn5p to a crippled origin

Maria Claudia Espinosa; Muhammad Attiq Rehman; Patricia Chisamore-Robert; Daniel Jeffery; Krassimir Yankulov; Anja-Katrin Bielinsky

2010-01-01

351

Vacuolar morphology of Saccharomyces cerevisiae during the process of wine making and Japanese sake brewing  

Microsoft Academic Search

Although ethanol and osmotic stress affect the vacuolar morphology of Saccharomyces cerevisiae, little information is available about changes in vacuolar morphology during the processes of wine making and Japanese sake (rice wine) brewing. Here, we elucidated changes in the morphology of yeast vacuoles using Zrc1p-GFP, a vacuolar membrane\\u000a protein, so as to better understand yeast physiology during the brewing process.

Shingo Izawa; Kayo Ikeda; Takeo Miki; Yoshinori Wakai; Yoshiharu Inoue

2010-01-01

352

Establishment of a simple and effective isolation method for cyanophycin from recombinant Saccharomyces cerevisiae  

Microsoft Academic Search

An efficient, time-saving, and cost-effective method for isolation of the polyamide cyanophycin from recombinant Saccharomyces cerevisiae was established. Due to its simple procedure, this isolation method may be also applicable at industrial scale and also to\\u000a other intracellular compounds in this yeast. Production of cyanophycin gained preferential interest in the past, as degradation\\u000a products thereof are of pharmaceutical and technical

Anna Steinle; Alexander Steinbchel

2010-01-01

353

High cell density fermentation of Saccharomyces cerevisiae GS2 for selenium-enriched yeast production  

Microsoft Academic Search

This paper describes a fed-batch fermentation protocol about production of selenium-enriched yeast. Saccharomyces cerevisiae GS2 was selected because of its high tolerance to selenium. The strain GS2 was tested and 1220.5 gl\\u000a ?1 dry cell weight was obtained after 30 h cultivation through feed back control of feed rate of glucose according to the concentration\\u000a of ethanol and dissolved oxygen.

Zheng Wang; Liyang Zhang; Tianwei Tan

2010-01-01

354

Acetaldehyde addition throughout the growth phase alleviates the phenotypic effect of zinc deficiency in Saccharomyces cerevisiae  

Microsoft Academic Search

During experiments to determine the effects of exogenously added acetaldehyde on pure cultures of various yeast strains, we\\u000a discovered that an early acetaldehyde perfusion during the growth phase allowed several yeasts to partially overcome the phenotypic\\u000a effects of zinc depletion during alcoholic fermentation. We, therefore, performed genome-wide expression and proteomic analysis\\u000a on an industrial Saccharomyces cerevisiae yeast strain (VL1) growing

Naoufel Cheraiti; Franois-Xavier Sauvage; Jean-Michel Salmon

2008-01-01

355

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 33C around 120gl -1 ethanol produced in 30h with a slight benefit for growth at 30C and for

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

2004-01-01

356

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

357

Small Ubiquitin-Related Modifier Pathway Is a Major Determinant of Doxorubicin Cytotoxicity in Saccharomyces cerevisiae  

Microsoft Academic Search

Development of drug resistance is a major challenge in cancer chemotherapy using doxorubicin. By screening the collection of Saccharomyces cerevisiae deletion strains to identify doxorubicin-resistant mutants, we have discovered that the small ubiquitin-related modifier (SUMO) pathway is a major determinant of doxorubicin cytotoxicity in yeast. Mutants lacking UBA2 (SUMO activating enzyme; E1), UBC9 (conjugat- ing enzyme; E2), and ULP1 and

Ruea-Yea Huang; David Kowalski; Hans Minderman; Nishant Gandhi; Erica S. Johnson

358

Identification of Saccharomyces cerevisiae Genes Involved in the Resistance to Phenolic Fermentation Inhibitors  

Microsoft Academic Search

Saccharomyces cerevisiae was exposed to inhibitory concentrations of the three phenolic phenylpropanoids: coniferyl aldehyde, ferulic acid, and isoeugenol.\\u000a Deoxyribonucleic acid microarray analysis was employed as one approach to generate a set of candidate genes for deletion mutant\\u000a analysis to determine the potential contribution of the corresponding gene products to the resistance against toxic concentrations\\u000a of phenolic fermentation inhibitors. Three S.

Linda Sundstrm; Simona Larsson; Leif J. Jnsson

2010-01-01

359

Genetic immobilization of cellulase on the cell surface of Saccharomyces cerevisiae  

Microsoft Academic Search

We tried genetically to immobilize cellulase protein on the cell surface of the yeast Saccharomyces cerevisiae in its active form. A cDNA encoding FI-carboxymethylcellulase (CMCase) of the fungus Aspergillus aculeatus, with its secretion signal peptide, was fused with the gene encoding the C-terminal half (320 amino acid residues from the\\u000a C terminus) of yeast ?-agglutinin, a protein involved in mating

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

1997-01-01

360

Nucleosome Remodeling and Transcriptional Repression Are Distinct Functions of Isw1 in Saccharomyces cerevisiae  

Microsoft Academic Search

The SANT domain is a nucleosome recognition module found in transcriptional regulatory proteins, includ- ing chromatin-modifying enzymes. It shows high functional degeneracy between species, varying in sequence and copy number. Here, we investigate functions in vivo associated with two SANT motifs, SANT and SLIDE, in the Saccharomyces cerevisiae Isw1 chromatin-remodeling ATPase. We show that differences in the primary structures of

Marina Pinskaya; Anitha Nair; David Clynes; Antonin Morillon; Jane Mellor

2009-01-01

361

Engineering of Polyploid Saccharomyces cerevisiae for Secretion of Large Amounts of Fungal Glucoamylase  

Microsoft Academic Search

We engineered Saccharomyces cerevisiae cells that produce large amounts of fungal glucoamylase (GAI) from Aspergillus awamori var. kawachi. To do this, we used the -sequence-mediated integration vector system and the heat-induced endomitotic diploidization method. -Sequence-mediated integration is known to occur mainly in a particular chromosome, and the copy number of the integration is variable. In order to construct transformants carrying

Keisuke Ekino; Hiroyuki Hayashi; Masahiro Moriyama; Minoru Matsuda; Masatoshi Goto; Sadazo Yoshino; Kensuke Furukawa

2002-01-01

362

Analysis of the energy metabolism after incubation of Saccharomyces cerevisiae with sulfite or nitrite  

Microsoft Academic Search

After addition of 5 mM sulfite or nitrite to glucose-metabolizing cells of Saccharomyces cerevisiae a rapid decrease of the ATP content and an inversely proportional increase in the level of inorganic phosphate was observed. The concentration of ADP shows only small and transient changes. Cells of the yeast mutant pet 936, lacking mitochondrial F1ATPase, after addition of 5 mM sulfite

Helga Hinze; Helmut Holzer

1986-01-01

363

Screening of a Saccharomyces cerevisiae nonessential gene deletion collection for altered susceptibility to a killer peptide.  

PubMed

Approximately 4,800 Saccharomyces cerevisiae mutants deleted for nonessential genes were screened for alterations in susceptibility to a synthetic killer peptide (KP). None of the tested strains, including mutants resistant to conventional antifungal drugs, showed increased or decreased susceptibility to KP in comparison with the parental strain. The results may reflect the peculiar mechanism of action of KP and claim the possible avoidance of vital resistant mutants. PMID:18437854

Conti, Stefania; Magliani, Walter; Giovati, Laura; Libri, Irene; Maffei, Domenico Leonardo; Salati, Antonella; Polonelli, Luciano

2008-01-01

364

A partial defect in carbon catabolite repression in mutants of Saccharomyces cerevisiae with reduced hexose phosphyorylation  

Microsoft Academic Search

Mutants of Saccharomyces cerevisiae with reduced glucose phosphorylation were investigated. They were all recessive and belonged to one gene HEX1, mutant designation hex1. Carbon catabolite repression of alpha-glucosidases, invertase and part of the total malate dehydrogenase was reduced. Repression of the glyoxylate cycle enzymes, isocitrate lyase and malate synthetase, as well as that of gluconeogenetic fructose-1, 6-bisphosphatase was normal. A

K.-D. Entian; F. K. Zimmermann; I. Scheel

1977-01-01

365

Ethanol production by Saccharomyces cerevisiae and Kluyveromyces marxianus in the presence of orange-peel oil  

Microsoft Academic Search

SummaryTwo ethanologenic yeasts, Saccharomyces cerevisiae and Kluyveromyces marxianus, were used to ferment sugar solutions modeling hydrolyzed Valencia orange peel waste at 37?C. Orange stripper oil produced\\u000a from orange peel was added in various amounts to determine its effect on ethanol production. The minimum peel oil concentration\\u000a that inhibited ethanol production was determined after 24, 48 and 72h and the two

Mark R. Wilkins; Lilis Suryawati; Niels O. Maness; Donna Chrz

2007-01-01

366

INDUCTION OF THE METHIONINE-ACTIVATING ENZYME IN SACCHAROMYCES CEREVISIAE1  

PubMed Central

Pigg, C. JoAnne (Oregon State University, Corvallis), W. A. Sorsoli, and L. W. Parks. Induction of the methionine-activating enzyme in Saccharomyces cerevisiae. J. Bacteriol. 87:920923. 1964.The methionine-activating enzyme was induced in yeast in the presence of methionine, resulting in an accumulation of S-adenosylmethionine. Formation of the sulfonium derivative prevented the accumulation of high levels of free methionine in induced cells. The physiological significance of this phenomenon is discussed.

Pigg, C. Joanne; Sorsoli, W. A.; Parks, L. W.

1964-01-01

367

Overexpression and purification of the vanilloid receptor in yeast ( Saccharomyces cerevisiae)  

Microsoft Academic Search

The vanilloid receptor type 1 (VR1) is a novel membrane receptor activated by heat or chemical ligands conveying information about chemosensitive and thermosensitive pain. We have overexpressed and purified wild type VR1 (wtVR1) as well as several mutant forms using the yeast strain Saccharomyces cerevisiae with the goal of obtaining sufficient protein for structural studies. To facilitate the rapid assaying

Vera Yu Moiseenkova; Helen L Hellmich; Burgess N Christensen

2003-01-01

368

Omics Tools for Environmental Monitoring of Chemicals, Radiation, and Physical Stresses in Saccharomyces Cerevisiae  

Microsoft Academic Search

The yeast Saccharomyces cerevisiae is one of the most characterized eucaryotes and its complete genome sequence was published in 1986. Thus, this organism is\\u000a a good candidate for biological environmental monitoring. Omics (genomics, proteomics, metabolomics) technology is being applied\\u000a to biological studies from prokaryotes to humans. We are applying omics technologies to environmental monitoring using yeast\\u000a cells, medaka, rice, rat,

Yoshihide Tanaka; Tetsuji Higashi; Randeep Rakwal; Junko Shibato; Emiko Kitagawa; Satomi Murata; Shin-ichi Wakida; Hitoshi Iwahashi

369

Distribution and functional diversification of the ras superfamily in Saccharomyces cerevisiae  

Microsoft Academic Search

The recent availability of the full Saccharomyces cerevisiae genome sequence offers a first opportunity to analyze the composition, function and evolution of GTPases in the ras-p21 superfamily. This superfamily in yeast is composed of 29 proteins divided into five families: ras with four sequences implicated in cell signalling; rho, six genes related to the cell shape machinery; ypt-rab, ten proteins

Juan Antonio Garcia-Ranea; Alfonso Valencia

1998-01-01

370

Bleomycin-induced DNA repair by Saccharomyces cerevisiae ATP-dependent polydeoxyribonucleotide ligase  

SciTech Connect

In contrast to ligase-deficient (cdc9) Saccharomyces cerevisiae, which did not rejoin bleomycin-induced DNA breaks, ligase-proficient (CDC9) yeast cells eliminated approximately 90% of DNA breaks within 90 to 120 min after treatment. Experimental conditions restricted enzymatic removal of the unusual 3{prime}-phosphoglycolate terminal in DNA cleaved by bleomycin and involved doses producing equivalent numbers of DNA breaks or doses producing equivalent killing.

Moore, C.W. (Univ. of Rochester School of Medicine and Dentistry, NY (USA))

1988-10-01

371

Heterologous expression in Saccharomyces cerevisiae of an Arabidopsis thaliana cDNA encoding mevalonate diphosphate decarboxylase  

Microsoft Academic Search

Sequence comparison with the mevalonate diphosphate decarboxylase (MVD) amino acid sequence of Saccharomyces cerevisiae identified an EST clone corresponding to a cDNA that may encode Arabidopsis thaliana MVD (AtMVD1). This enzyme catalyses the synthesis of isopentenyl diphosphate, the building block of sterol and isoprenoid biosynthesis, and uses mevalonate diphosphate as a substrate. Sequencing of the full-length cDNA was performed. The

Hlne Cordier; Francis Karst; Thierry Bergs

1999-01-01

372

Analysis of Plasmid Deletion Induced by Ionizing Radiation in Yeast Saccharomyces cerevisiae  

NASA Astrophysics Data System (ADS)

The article is dedicated to the research of plasmid system YCpL2 with help of quantitative analysis of deletion formation. The cells of yeast Saccharomyces cerevisiae were irradiated by ?-ray with the flux of 0.7 Gy/min and energy of 1.3 MeV as well as heavy ion beam 11B with energy 32 MeV/n. The deletion of plasmid DNA has been analyzed by genetic and restriction analysis.

Yatsevich, E.; Stepanova, A.; Sprincova, A.; Koltovaya, N.

2007-11-01

373

Cysteine addition strategy for maximum glutathione production in fed-batch culture of Saccharomyces cerevisiae  

Microsoft Academic Search

A good cysteine addition method that could increase the specific glutathione (GSH) production rate (G9G) was investigated and utilized to maximize total GSH production in fed-batch culture of Saccharomyces cerevisiae. The single-shot addition of cysteine was a better method compared to a continuous method that maintained a constant cysteine concentration in the reactor. The shot method increased ?G about twofold

Catalino Alfafara; Keigo Miura; Hiroshi Shimizu; Suteaki Shioya; Ken-ichi Suga

1992-01-01

374

Removing heavy metals from synthetic effluents using kamikaze Saccharomyces cerevisiae cells  

Microsoft Academic Search

One key step of the bioremediation processes designed to clean up heavy metal contaminated environments is growing resistant\\u000a cells that accumulate the heavy metals to ensure better removal through a combination of biosorption and continuous metabolic\\u000a uptake after physical adsorption. Saccharomyces cerevisiae cells can easily act as cation biosorbents, but isolation of mutants that are both hyperaccumulating and tolerant to

Lavinia Ruta; Codruta Paraschivescu; Mihaela Matache; Sorin Avramescu; Ileana Cornelia Farcasanu

2010-01-01

375

Interactions between gene products involved in divalent cation transport in Saccharomyces cerevisiae  

Microsoft Academic Search

The COT1 and ZRC1 genes of Saccharomyces cerevisiae are structurally related dosage-dependent suppressors of metal toxicity. COT1 confers increased tolerance to high levels of cobalt; ZRC1 confers increased tolerance to high levels of zinc. The two genes are not linked and have been mapped; COT1 to chromosome XV and ZRC1 to chromosome XIII. Phenotypes related to metal homeostasis have been

Douglas S. Conklin; Michael R. Culbertson; Ching Kung

1994-01-01

376

Methylamine\\/ammonia uptake systems in Saccharomyces cerevisiae : multiplicity and regulation  

Microsoft Academic Search

Three lines of evidence show that the uptake of methylamine\\/ammonia in Saccharomyces cerevisiae is mediated by at least two functionally distinct mechanisms.1.Lineweaver-Burk plots for methylamine uptake show an abrupt transition between apparently linear sections, and both functions are inhibited competitively by ammonia.2.These functions can be lost separately as a result of the two genetically unlinked mutations mep-1 and mep-2. Double

Evelyne Dubois; Marcelle Grenson

1979-01-01

377

Overexpression of cytosolic malate dehydrogenase (MDH2) causes overproduction of specific organic acids in Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae accumulates l-malic acid through a cytosolic pathway starting from pyruvic acid and involving the enzymes pyruvate carboxylase and malate\\u000a dehydrogenase. In the present study, the role of malate dehydrogenase in the cytosolic pathway was studied. Overexpression\\u000a of cytosolic malate dehydrogenase (MDH2) under either the strong inducible GAL10 or the constitutive PGK promoter causes a\\u000a 6- to 16-fold increase

O. Pines; S. Shemesh; E. Battat; I. Goldberg

1997-01-01

378

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

Microsoft Academic Search

The hexose-proton symporter HUP1 shows a spotty distribution in the plasma membrane of the green alga Chlorella kessleri. Chlorella cannot be transformed so far. To study the membrane localization of the HUP1 protein in detail, the symporter was fused to green fluorescent protein (GFP) and heterologously expressed in Saccharomyces cerevisiae and Schizosaccharomyces pombe. In these organisms, the HUP1 protein has

Guido Grossmann; Miroslava Opekarova; Linda Novakova; Jurgen Stolz; Widmar Tanner

2006-01-01

379

Counting of Rif1p and Rif2p on Saccharomyces cerevisiae Telomeres Regulates Telomere Length  

Microsoft Academic Search

Telomere length is negatively regulated by proteins of the telomeric DNA-protein complex. Rap1p in Saccharomyces cerevisiae binds the telomeric TG1-3 repeat DNA, and the Rap1p C terminus interacts with Rif1p and Rif2p. We investigated how these three proteins negatively regulate telomere length. We show that direct tethering of each Rif protein to a telomere shortens that telomere proportionally to the

Daniel L. Levy; Elizabeth H. Blackburn

2004-01-01

380

Physical interaction of Cdc28 with Cdc37 in Saccharomyces cerevisiae  

Microsoft Academic Search

The Cdc37 protein in Saccharomyces cerevisiae is thought to be a kinase-targeting subunit of the chaperone Hsp90. In a genetic screen, four protein kinases were identified as interacting with Cdc37 - Cdc5, Cdc7, Cdc15 and Cak1. This result underlines the importance of Cdc37 for the folding of protein kinases. In addition, we showed that Ydj1, a yeast DnaJ homolog belonging

M. Mort-Bontemps-Soret; C. Facca; G. Faye

2002-01-01

381

Phenylalanine and tyrosine-auxotrophic mutants of Saccharomyces cerevisiae impaired in transamination  

Microsoft Academic Search

This paper reports the first isolation of Saccharomyces cerevisiae mutants lacking aromatic aminotransferase I activity (aro8), and of aro8 aro9 double mutants which are auxotrophic for both phenylalanine and tyrosine, because the second mutation, aro9, affects aromatic aminotransferase II. Neither of the single mutants displays any nutritional requirement on minimal ammonia\\u000a medium. In vitro, aromatic aminotransferase I is active not

A. Urrestarazu; S. Vissers; I. Iraqui; M. Grenson

1998-01-01

382

Functional expression of cellobiohydrolases in Saccharomyces cerevisiae towards one-step conversion of cellulose to ethanol  

Microsoft Academic Search

To investigate the possible use of Saccharomyces cerevisiae as a candidate for consolidated bioprocessing (CBP) of cellulose to ethanol, four fungal cellobiohydrolase (CBH) encoding genes (Trichoderma reesei cbh1 and cbh2, Aspergillus niger cbhB and Phanerochaete chrysosporium cbh14) were expressed in this yeast. All four CBHs were successfully expressed and similar extracellular activity was demonstrated on phosphoric acid swollen cellulose (PASC)

Riaan Den Haan; John E. Mcbride; Danil C. La Grange; Lee R. Lynd; Willem H. Van Zyl

2007-01-01

383

Proteomic insights into adaptive responses of Saccharomyces cerevisiae to the repeated vacuum fermentation  

Microsoft Academic Search

The responses and adaptation mechanisms of the industrial Saccharomyces cerevisiae to vacuum fermentation were explored using proteomic approach. After qualitative and quantitative analyses, a total of 106\\u000a spots corresponding to 68 different proteins were identified by matrix-assisted laser desorption\\/ionization time-of-flight\\u000a mass spectrometry. The differentially expressed proteins were involved in amino acid and carbohydrate metabolisms, various\\u000a signal pathways (Ras\\/MAPK, Rascyclic adenosine

Jing-Sheng Cheng; Xiao Zhou; Ming-Zhu Ding; Ying-Jin Yuan

2009-01-01

384

High-level secretion of human ? 1-antitrypsin from Saccharomyces cerevisiae using inulinase signal sequence  

Microsoft Academic Search

The use of a proper signal sequence is one of the major determinants for the efficient secretion of heterologous proteins from yeast. The signal sequence derived from inulinase (INU1A) of Kluyveromyces marxianus was evaluated in directing the secretion of a human glycoprotein, ?1-antitrypsin (?1-AT), from Saccharomyces cerevisiae. A yeast expression vector for ?1-AT was constructed by placing the coding sequence

Hyun Ah Kang; Soo Wan Nam; Ki-sun Kwon; Bong Hyun Chung; Myeong-hee Yu

1996-01-01

385

A method to increase silver biosorption by an industrial strain of Saccharomyces cerevisiae  

Microsoft Academic Search

Ag+ biosorption by an industrial strain of Saccharomyces cerevisiae was investigated. Older (96 h old) biomass had half the biosorption capacity of younger (24 h old) biomass (0.187 and 0.387\\u000a mmol Ag+\\/g dry mass respectively). Comparisons of cell walls isolated from biomass of either age indicated that chemical composition\\u000a and Ag+ biosorption capacity varied little over the time span examined

P. Simmons; I. Singleton

1996-01-01

386

Production of kefir like product from mixed cultures of Saccharomyces cerevisiae, Streptococcus cremoris and Streptococcus lactis  

Microsoft Academic Search

Various ratios of Streptococcus cremoris to Streptococcus lactis, 0.5 : 1.5, 1 : 1 and 1.5 : 0.5% were added to milk supplemented with 5% (w\\/v) sucrose. Fermentation temperature was kept constant at 30oC. For the first 15 h of fermentation, the milk was fermented by 5% (v\\/v) Saccharomyces cerevisiae, followed by lactic acid bacteria. The total fermentation time was

Pongpakorn Kaewprasert; Naiyatat Poosaran

387

Efficient expression and secretion of Aspergillus niger RH5344 polygalacturonase in Saccharomyces cerevisiae  

Microsoft Academic Search

An Aspergillus niger endopolygalacturonase (EC 3.2.1.15) cDNA was expressed in the yeast Saccharomyces cerevisiae. Secretion of the protein into the growth medium was efficiently directed by the fungal leader sequence, and processing occurred at the same site as in Aspergillus. The expression level was significantly enhanced by using a short version of the yeast ADHI promoter. An additional increase in

C. Lang; A. C. Looman

1995-01-01

388

The use of biotin tagging in Saccharomyces cerevisiae improves the sensitivity of chromatin immunoprecipitation  

Microsoft Academic Search

Affinity tagging has been used in many global stu- dies towards protein function. We describe a highly efficient system for in vivo biotinylation of transcrip- tion factors in the yeast Saccharomyces cerevisiae, which is based on the bacterial BirA biotin ligase. The strength of the biotin-streptavidin interaction was exploited to improve detection of in vivo protein-DNA complexes in chromatin immunopre-

Folkert J. van Werven; Marc Timmers

2006-01-01

389

[Study of PLi genes action on the cell wall structure of "Saccharomyces cerevisiae" Hansen (author's transl)].  

PubMed

A study of the composition of cell walls extracted from a wild strain and three mutant strains "smooth colony" of Saccharomyces cerevisiae had been done. It points out differences in the mannose/glucose ratio and in the concentration of some other components of the cell wall in the mutant strains. The immunological study of the cell wall shows that "smooth colonies" mutants and wild strains differs in their mannoproteins. PMID:76456

Delpech, I; Bizeau, C; Bonaly, R; Galzy, P

1977-01-01

390

Functional expression of amine oxidase from Aspergillus niger (AO-I) in Saccharomyces cerevisiae  

Microsoft Academic Search

The aim of this work was to prepare recombinant amine oxidase from Aspergillus niger after overexpressing in yeast. The yeast expression vector pDR197 that includes a constitutive PMA1 promoter was used for\\u000a the expression in Saccharomyces cerevisiae. Recombinant amine oxidase was extracted from the growth medium of the yeast, purified to homogeneity and identified by activity\\u000a assay and MALDI-TOF peptide

Kate?ina Kola?kov; Petr Galuszka; Iva Sedl?ov; Marek ebela; Ivo Frbort

2009-01-01

391

Functioning of Saccharomyces cerevisiae Pma1 H + ATPase carrying the minimal number of cysteine residues  

Microsoft Academic Search

Pma1 H+-ATPase is the primary proton pump in the plasma membrane of the yeast Saccharomyces cerevisiae. It generates an electrochemical proton gradient, thus providing energy for secondary solute transport systems. The enzyme\\u000a contains nine cysteines, three (Cys148, Cys312, and Cys867) in transmembrane segments and the rest (Cys221, Cys376, Cys409,\\u000a Cys472, Cys532, and Cys569) in the cytosolic parts of the molecule.

V. V. Petrov

2009-01-01

392

Bioethanol production performance of five recombinant strains of laboratory and industrial xylose-fermenting Saccharomyces cerevisiae  

Microsoft Academic Search

In this study, five recombinant Saccharomyces cerevisiae strains were compared for their xylose-fermenting ability. The most efficient xylose-to-ethanol fermentation was found by using the industrial strain MA-R4, in which the genes for xylose reductase and xylitol dehydrogenase from Pichia stipitis along with an endogenous xylulokinase gene were expressed by chromosomal integration of the flocculent yeast strain IR-2. The MA-R4 strain

Akinori Matsushika; Hiroyuki Inoue; Katsuji Murakami; Osamu Takimura; Shigeki Sawayama

2009-01-01

393

Characterisation of thermotolerant, ethanol tolerant fermentative Saccharomyces cerevisiae for ethanol production  

Microsoft Academic Search

Of the four thermotolerant, osmotolerant, flocculating yeasts (VS1, VS2, VS3 and VS4) isolated from the soil samples collected within the hot regions of Kothagudem Thermal Power Plant, located in Khammam Dt., Andhra Pradesh, India, VS1 and VS3 were observed as better performers. They were identified as Saccharomyces cerevisiae. VS1 and VS3 were tested for their growth characteristics and fermentation abilities

N. Kiransree; M. Sridhar; L. Venkateswar Rao

2000-01-01

394

Evidence for a Conserved System for Iron Metabolism in the Mitochondria of Saccharomyces cerevisiae  

Microsoft Academic Search

nifU of nitrogen-fixing bacteria is involved in the synthesis of the Fe-S cluster of nitrogenase. In a synthetic lethal screen with the mitochondrial heat shock protein (HSP)70, SSQ1, we identified a gene of Saccharomyces cerevisiae, NFU1, which encodes a protein with sequence identity to the C-terminal domain of NifU. Two other yeast genes were found to encode proteins related to

Brenda Schilke; Cindy Voisine; Helmut Beinert; Elizabeth Craig

1999-01-01

395

Saccharomyces cerevisiae Expresses Three Functionally Distinct Homologues of the Nramp Family of Metal Transporters  

Microsoft Academic Search

The baker's yeast Saccharomyces cerevisiae expresses three homologues of the Nramp family of metal transporters: Smf1p, Smf2p, and Smf3p, encoded by SMF1, SMF2, and SMF3, respectively. Here we report a comparative analysis of the yeast Smf proteins at the levels of localization, regulation, and function of the corresponding metal transporters. Smf1p and Smf2p function in cellular accumulation of manganese, and

MATTHEW E. PORTNOY; XIU FEN LIU; VALERIA CIZEWSKI CULOTTA

2000-01-01

396

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

397

Saccharomyces cerevisiae strains with different degrees of ethanol tolerance exhibit different adaptive responses to produced ethanol  

Microsoft Academic Search

Two Saccharomyces cerevisiae strains with different degrees of ethanol tolerance adapted differently to produced ethanol. Adaptation in the less ethanol-tolerant\\u000a strain was high and resulted in a reduced formation of ethanol-induced respiratory deficient mutants and an increased ergosterol\\u000a content of the cells. Adaptation in the more ethanol-tolerant strain was less pronounced. Journal of Industrial Microbiology & Biotechnology (2000) 24, 7578.

Z Chi; N Arneborg

2000-01-01

398

High alcohol production by repeated batch fermentation using an immobilized osmotolerant Saccharomyces cerevisiae  

Microsoft Academic Search

A repeated batch fermentation system was used to produce ethanol using an osmotolerant Saccharomyces cerevisiae (VS3) immobilized in calcium alginate beads. For comparison free cells were also used to produce ethanol by repeated batch fermentation.\\u000a Fermentation was carried for six cycles with 125, 250 or 500 beads using 150, 200 or 250?g glucose L?1 at 30C. The maximum amount of

N Kiran Sree; M Sridhar; K Suresh; I M Banat; L Venkateswar Rao

2000-01-01

399

CLONING AND HETEROLOGOUS EXPRESSION OF CRYPTOCOCCUS NEOFORMANS CNSRB1 CDNA IN SACCHAROMYCES CEREVISIAE  

Microsoft Academic Search

In this study, we report the results of cloning, sequencing and functional analysis by complementation test of the putative Cryptococcus neoformans homolog CnSRB1. The nucle- otide sequence revealed 63% identity, and the deduced amino acid sequence showed 66 and 64% identity to its respective homolog of Saccharomyces cerevisiae and Candida albicans, respectively. Functional complementation test indicated that the putative CnSRB1

Saradee Warit; Lubomira I Stateva; Prasit Palittapongarnpim

2008-01-01

400

The effect of trehalose on the fermentation performance of aged cells of Saccharomyces cerevisiae  

Microsoft Academic Search

The fermentation process offers a wide variety of stressors for yeast, such as temperature, aging, and ethanol. To evaluate\\u000a a possible beneficial effect of trehalose on ethanol production, we used mutant strains of Saccharomyces cerevisiae possessing different deficiencies in the metabolism of this disaccharide: in synthesis, tps1; in transport, agt1; and in degradation, ath1 and nth1. According to our results,

Eduardo T. V. Trevisol; Anita D. Panek; Sergio Cantu Mannarino; Elis C. A. Eleutherio

2011-01-01

401

Molecular Population Genetics and Evolution of a Prion-like Protein in Saccharomyces cerevisiae  

Microsoft Academic Search

The prion-like behavior of Sup35p, the eRF3 homolog in the yeast Saccharomyces cerevisiae, mediates the activity of the cytoplasmic nonsense suppressor known as (PSI). Sup35p is divided into three regions of distinct function. The N-terminal and middle (M) regions are required for the induction and propagation of (PSI) but are not necessary for translation termination or cell viability. The C-terminal

Mark A. Jensen; Heather L. True; Yury O. Chernoff; Susan Lindquist

2001-01-01

402

Transcription factor control of growth rate dependent genes in Saccharomyces cerevisiae: A three factor design  

Microsoft Academic Search

BACKGROUND: Characterization of cellular growth is central to understanding living systems. Here, we applied a three-factor design to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostat cultures of Saccharomyces cerevisiae. The three factors we considered were specific growth rate, nutrient limitation, and oxygen availability. RESULTS: We identified 268 growth rate dependent genes, independent

Alessandro Fazio; Michael C. Jewett; Pascale Daran-Lapujade; Roberta Mustacchi; Renata Usaite; Jack T. Pronk; Christopher T. Workman; Jens Nielsen

2008-01-01

403

Characterization of staurosporine-sensitive mutants of Saccharomyces cerevisiae : vacuolar functions affect staurosporine sensitivity  

Microsoft Academic Search

Mutations at several loci affect the sensitivity of the yeast Saccharomyces cerevisiae to staurosporine. We report here the characterization of novel staurosporine- and temperature-sensitive mutants (stt). Cloning and integration mapping showed that the genes STT2\\/STT6, STT5, STT7, STT8 and STT9 are allelic to VPS18, ERG10, GPI1, VPS34 and VPS11, respectively. The products of ERG10 and GPI1, respectively, catalyze mevalonate and

S. Yoshida; Y. Anraku

2000-01-01

404

Analysis of factors responsible for the regeneration to intact cells from sphaeroplasts of Saccharomyces cerevisiae  

Microsoft Academic Search

The regeneration of Saccharomyces cerevisiae, NCIM 3288, cells from its sphaeroplasts were found to be influenced by a number of factors. The most suitable conditions of regeneration were also dependent on growth medium, that is, using malt-extractglucose-yeast extract-peptone (MGYP) medium: mannitol 0.7 M, pH 6.5, 30 C and using yeast extract-peptone-glucose (YPG) medium: sucrose 0.7 M, pH 5.0 and 30

J. Anjani Kumari; T. Panda

1994-01-01

405

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

406

Influence of Saccharomyces cerevisiae strains on wine total antioxidant capacity evaluated by photochemiluminescence  

Microsoft Academic Search

A preliminary investigation on 20 Aglianico del Vulture commercial wines from the Basilicata region proved the existence of\\u000a a significant variability in total antioxidant capacity which can exert a potential impact on wine quality. Nineteen Saccharomyces cerevisiae strains were tested in Aglianico del Vulture on pilot scale fermentation and the experimental wines obtained were evaluated\\u000a for the antioxidant capacity, ethanol

Vincenzo Brandolini; Concetta Fiore; Annalisa Maietti; Paola Tedeschi; Patrizia Romano

2007-01-01

407

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

408

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

Microsoft Academic Search

Saccharomyces cerevisiae yeast cells serve as a model to elucidate the bases of salt tolerance and potassium homeostasis regulation in eukaryotic cells. In this study, we show that two widely used laboratory strains, BY4741 and W303-1A, differ not only in cell size and volume but also in their relative plasma-membrane potential (estimated with a potentiometric fluorescent dye diS-C3(3) and as

Silvia Petrezselyova; Jaromir Zahradka; Hana Sychrova

2010-01-01

409

Extracellular processing of carboxypeptidase Y secreted by a Saccharomyces cerevisiae ssl1 mutant strain  

Microsoft Academic Search

Carboxypeptidase Y (CPY; EC 3. 4. 16. 1) encoded by the PRC1 gene is a yeast vacuolar protease. It enters the vacuole as a zymogen, proCPY, which is activated by vacuolar enzymes, proteinase A (PrA) and proteinase B (PrB). We previously showed that active CPY was efficiently secreted from the Saccharomyces cerevisiae ssl1 (supersecretion of lysozyme) mutant carrying a multicopy

Yoichiro Shiba; Kimihisa Ichikawa; Nobufusa Serizawa; Hiroji Yoshikawa

1998-01-01

410

Analogs of squalene and oxidosqualene inhibit oxidosqualene cyclase of Trypanosoma cruzi expressed in Saccharomyces cerevisiae  

Microsoft Academic Search

Recently, a number of inhibitors of the enzyme oxidosqualene cyclase (OSC; EC 5.4.99.7), a key enzyme in sterol biosynthesis,\\u000a were shown to inhibit in mammalian cells the multiplication of Trypanosoma cruzi, the parasite agent of Chagas disease. The gene coding for the OSC of T. cruzi has been cloned and expressed in Saccharomyces cerevisiae. The expression in yeast cells could

Simonetta Oliaro-Bosso; Maurizio Ceruti; Gianni Balliano; Paola Milla; Flavio Rocco; Franca Viola

2005-01-01

411

RNA Polymerase II Elongation Factors of Saccharomyces cerevisiae: a Targeted Proteomics Approach  

Microsoft Academic Search

To physically characterize the web of interactions connecting the Saccharomyces cerevisiae proteins suspected to be RNA polymerase II (RNAPII) elongation factors, subunits of Spt4\\/Spt5 and Spt16\\/Pob3 (corresponding to human DSIF and FACT), Spt6, TFIIF (Tfg1, -2, and -3), TFIIS, Rtf1, and Elongator (Elp1, -2, -3, -4, -5, and -6) were affinity purified under conditions designed to minimize loss of associated

Nevan J. Krogan; Minkyu Kim; Seong Hoon Ahn; Guoqing Zhong; Michael S. Kobor; Gerard Cagney; Andrew Emili; Ali Shilatifard; Stephen Buratowski; Jack F. Greenblatt

2002-01-01

412

Saccharomyces cerevisiae translational activator Cbs2p is associated with mitochondrial ribosomes  

Microsoft Academic Search

A characteristic feature of the mitochondrial expression system in Saccharomyces cerevisiae is the requirement for gene-specific translational activator proteins. Translation of mitochondrial apocytochrome b mRNA requires the nucleus-encoded proteins Cbs1p and Cbs2p. These proteins are thought to tether cytochrome b mRNA to the mitochondrial inner membrane via binding to the 5' untranslated mRNA leader. Here, we demonstrate by the use

Udo Krause-Buchholz; Kathrin Barth; Cora Dombrowski; Gerhard Rdel

2004-01-01

413

Redox regulation of protein expression in Saccharomyces cerevisiae mitochondria: Possible role of VDAC  

Microsoft Academic Search

Using Saccharomyces cerevisiae mutants depleted of either isoform of VDAC (voltage dependent anion selective channel) we studied the role of the cytosol and mitochondria redox states in regulation of the expression levels of some mitochondrial proteins. The studied proteins are MnSOD and subunits of the protein import machinery of the mitochondrial outer membrane, i.e. Tom70, Tom40 and Tob55 (Sam50). We

Hanna Galganska; Malgorzata Budzinska; Malgorzata Wojtkowska; Hanna Kmita

2008-01-01

414

Lead induces oxidative stress and phenotypic markers of apoptosis in Saccharomyces cerevisiae  

Microsoft Academic Search

In the present work, the mode of cell death induced by Pb in Saccharomyces cerevisiae was studied. Yeast cells Pb-exposed, up to 6h, loss progressively the capacity to proliferate and maintained the membrane\\u000a integrity evaluated by the fluorescent probes bis(1,3-dibutylbarbituric acid trimethine oxonol) and propidium iodide. Pb-induced\\u000a death is an active process, requiring the participation of cellular metabolism, since the

Jurrian Vanden Bussche; Eduardo V. Soares

2011-01-01

415

Evaluation of Molecular Typing Techniques To Assign Genetic Diversity amongSaccharomyces cerevisiaeStrains  

Microsoft Academic Search

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, withTaqI andMseI, of PCR-amplified fragments

M. MARGARIDA BALEIRAS COUTO; BOB EIJSMA; HARMEN HOFSTRA; JOS H. J. HUIS; M. B. M. VAN DERVOSSEN

1996-01-01

416

Kinetics of ? 5,7 -sterol accumulation during growth of Saccharomyces cerevisiae  

Microsoft Academic Search

Saccharomyces cerevisiae accumulates ?5,7-sterols up to 4 mg per g biomass. The differential rate of sterol synthesis continually increases during growth, its value\\u000a only being decreased at sterol levels higher than 30 mg per g biomass. The specific rate of sterol synthesis reaches a broad\\u000a maximum during the growth phase. The gradual sterol accumulation pattern is dominant in cultures growing

?. Novotn; B. B?halov; L. Dolealov; J. Zaj?ek

1987-01-01

417

Frequencies of mutagen-induced coincident mitotic recombination at unlinked loci in Saccharomyces cerevisiae  

Microsoft Academic Search

Frequencies of coincident genetic events were measured in strain D7 of Saccharomyces cerevisiae. This diploid strain permits the detection of mitotic gene conversion involving the trp5-12 and trp5-27 alleles, mitotic crossing-over and gene conversion leading to the expression of the ade2-40 and ade2-119 alleles as red and pink colonies, and reversion of the ilv1-92 allele. The three genes are on

Kathryn M. Freeman; George R. Hoffmann

2007-01-01

418

Saccharomyces cerevisiae Produces a Yeast Substance that Exhibits Estrogenic Activity in Mammalian Systems  

NASA Astrophysics Data System (ADS)

Partially purified lipid extracts of Saccharomyces cerevisiae contain a substance that displaces tritiated estradiol from rat uterine cytosol estrogen receptors. The yeast product induces estrogenic bioresponses in mammalian systems as measured by induction of progesterone receptors in cultured MCF-7 human breast cancer cells and by a uterotrophic response and progesterone receptor induction after administration to ovariectomized mice. The findings raise the possibility that bakers' yeast may be a source of environmental estrogens.

Feldman, David; Stathis, Peter A.; Hirst, Margaret A.; Price Stover, E.; Do, Yung S.; Kurz, Walter

1984-06-01

419

Novel System for Monitoring Autophagy in the Yeast Saccharomyces cerevisiae  

Microsoft Academic Search

The yeast S. cerevisiae imports cytosolic components into the vacuole non-selectively by autophagy and degrades them by vacuolar hydrolases under nutrient starvation conditions. We developed a novel system for monitoring autophagy by constructing cells in which modified vacuolar alkaline phosphatase is expressed as an inactive precursor form in the cytosol. Under starvation conditions, the processing of the precursor to the

T. Noda; A. Matsuura; Y. Wada; Y. Ohsumi

1995-01-01

420

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.

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

2008-01-01

421

Divergence of glyceraldehyde-3-phosphate dehydrogenase isozymes in Saccharomyces cerevisiae complex.  

PubMed

Although sake yeasts are placed in Saccharomyces cerevisiae, we have been interested in their difference from the other subgroups of the species, and examined their proteins. When SDS-PAGE patterns of their soluble proteins were compared, specific differences between subgroups were found in their 36,000 Da regions. Proteins isolated therefrom were found to be subunits of three isomers of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from their N-terminal amino acid sequences and identified with anti-GAPDH serum. Therefore, comparison of zymogram was carried out by a modified method: denatured monomers were observed and the enzyme activity of their oligomers was not considered. SDS-PAGE patterns of all the sake yeasts differed from those of the other strains of S. cerevisiae. Strains of Saccharomyces bayanus showed uniform patterns which are different from the above two groups. Saccharomyces pastorianus strains resembled S. bayanus and were partly similar to S. cerevisiae in their patterns, in agreement with the hypothesis that S. pastorianus is a hybrid between these two species. Patterns of S. paradoxus appeared to be rather similar to those of sake yeasts. Results on the other species of the genus and on the preliminary experiments on PAGE of native isozymes are also described. PMID:10930071

Kadokura, T; Ito, T; Takano, S; Nakazato, A; Hara, H; Watanabe, S; Kudo, T; Takeda, M; Kaneko, T

2000-06-01

422

Interactions between Kluyveromyces marxianus and Saccharomyces cerevisiae in tequila must type medium fermentation.  

PubMed

Traditional tequila fermentation is a complex microbial process performed by different indigenous yeast species. Usually, they are classified in two families: Saccharomyces and Non-Saccharomyces species. Using mixed starter cultures of several yeasts genera and species is nowadays considered to be beneficial to enhance the sensorial characteristics of the final products (taste, odor). However, microbial interactions occurring in such fermentations need to be better understood to improve the process. In this work, we focussed on a Saccharomyces cerevisiae/Kluyveromyces marxianus yeast couple. Indirect interactions due to excreted metabolites, thanks to the use of a specific membrane bioreactor, and direct interaction due to cell-to-cell contact have been explored. Comparison of pure and mixed cultures was done in each case. Mixed cultures in direct contact showed that both yeast were affected but Saccharomyces rapidly dominated the cultures whereas Kluyveromyces almost disappeared. In mixed cultures with indirect contact the growth of Kluyveromyces was decreased compared to its pure culture but its concentration could be maintained whereas the growth of Saccharomyces was enhanced. The loss of viability of Kluyveromyces could not be attributed only to ethanol. The sugar consumption and ethanol production in both cases were similar. Thus the interaction phenomena between the two yeasts are different in direct and indirect contact, Kluyveromyces being always much more affected than Saccharomyces. PMID:24677041

Lopez, Claudia Lorena Fernandez; Beaufort, Sandra; Brandam, Cdric; Taillandier, Patricia

2014-08-01

423

Role of Saccharomyces cerevisiae serine O-acetyltransferase in cysteine biosynthesis.  

PubMed

Some strains of Saccharomyces cerevisiae have detectable activities of L-serine O-acetyltransferase (SATase) and O-acetyl-L-serine/O-acetyl-L-homoserine sulfhydrylase (OAS/OAH-SHLase), but synthesize L-cysteine exclusively via cystathionine by cystathionine beta-synthase and cystathionine gamma-lyase. To untangle this peculiar feature in sulfur metabolism, we introduced Escherichia coli genes encoding SATase and OAS-SHLase into S. cerevisiae L-cysteine auxotrophs. While the cells expressing SATase grew on medium lacking L-cysteine, those expressing OAS-SHLase did not grow at all. The cells expressing both enzymes grew very well without L-cysteine. These results indicate that S. cerevisiae SATase cannot support L-cysteine biosynthesis and that S. cerevisiae OAS/OAH-SHLase produces L-cysteine if enough OAS is provided by E. coli SATase. It appears as if S. cerevisiae SATase does not possess a metabolic role in vivo either because of very low activity or localization. For example, S. cerevisiae SATase may be localized in the nucleus, thus controlling the level of OAS required for regulation of sulfate assimilation, but playing no role in the direct synthesis of L-cysteine. PMID:12586406

Takagi, Hiroshi; Yoshioka, Kenji; Awano, Naoki; Nakamori, Shigeru; Ono, Bun ichiro

2003-01-28

424

Mechanisms of appearance of the Pasteur effect in Saccharomyces cerevisiae: inactivation of sugar transport systems.  

PubMed Central

Saccharomyces cerevisiae does not show a noticeable Pasteur effect (activation of sugar catabolism by anaerobiosis) when growing with an excess of sugar and nitrogen source, but it does do so after exhaustion of the nitrogen source in the medium (resting state). We have found that this different behavior of growing and resting S. cerevisiae seems due to differences in the contribution of respiration to catabolism under both states. Growing S. cerevisiae respired only 3 to 20% of the catabolized sugar, depending on the sugar present; the remainder was fermented. In contrast, resting S. cerevisiae respired as much as 25 to 100% of the catabolized sugar. These results suggest that a shift to anaerobiosis would have much greater energetic consequences in resting than in growing S. cerevisiae. In resting S. cerevisiae anaerobiosis would strongly decrease the formation of ATP; as a consequence, various regulatory mechanisms would switch on, producing the observed increase of the rate of glycolysis. The greater significance that respiration reached in resting cells was not due to an increase of the respiratory capacity itself, but to a loss of fermentation which turned respiration into the main catabolic pathway. The main mechanism involved in the loss of fermentation observed during nitrogen starvation was a progressive inactivation of the sugar transport systems that reduced the rate of fermentation to less than 10% of the value observed in growing cells. Inactivation of the sugar transports seems a consequence of the turnover of the sugar carriers whose apparent half-lives were 2 to 7 h.

Lagunas, R; Dominguez, C; Busturia, A; Saez, M J

1982-01-01

425

Identification of new chromosomes of Saccharomyces bayanus using gene probes from S. cerevisiae.  

PubMed

The Saccharomyces cerevisiae genes HIS3 (chr. XV), LYS2 (chr. II), ARG4 (chr. VIII), MF alpha 1 (chr. XVI) and MEL1 (chr. II) and the S. pastorianus gene MELx were used for identification of the homeologous chromosomes in S. bayanus by using pulsed-field gel electrophoresis and Southern blot hybridization. The results showed differences in hybridization intensities and mobilities between the homeologous chromosomes of the two sibling yeasts S. cerevisiae and S. bayanus. The probes HIS3, LYS2, MEL1, and MF alpha 1 identified four new homeologous chromosomes of S. bayanus. The ARG4 probe confirmed the previously identified location of chr. VIII (NAUMOV et al. 1992b). Using the MF alpha 1 gene, another chromosome besides chr. XVI was identified in some S. bayanus strains, suggesting translocation of this sequence to the S. bayanus chromosome that normally migrates to the position of chr. XI of S. cerevisiae. PMID:8083058

Naumov, G I; Naumova, E S; Gaillardin, C; Turakainen, H; Korhola, M

1994-01-01

426

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

PubMed

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

2014-04-01

427

Isolation and characterization of Saccharomyces cerevisiae mutants resistant to T-2 toxin.  

PubMed

T-2 toxin, a trichothecene mycotoxin, inhibits the growth of Saccharomyces cerevisiae. We have isolated nine spontaneous S. cerevisiae mutants resistant to this toxin. The mutants were distinguished from the wild type according to their degree of resistance to T-2 toxin on media with dextrose or glycerol as the carbon source. Generation time, mutation stability and level of cross-resistance to roridin A, another trichothecene, were determined for each mutant. The T-2 toxin resistant mutants were further characterized by subsequent tests involving cross-resistance and collateral sensitivity to chlorampenicol, neomycin, paromomycin, ethidium bromide and thiolutin. Mutants have been placed into three subgroups and the mechanism of T-2 toxin resistance in each group has been postulated. Mutant HK1 is the first S. cerevisiae isolate resistant to roridin A. One particular isolate, mutant HK11, carries a single recessive nuclear mutation. This mutation was termed ttt (for T-2 toxin resistant). PMID:3042165

Koshinsky, H A; Schappert, K T; Khachatourians, G G

1988-05-01

428

Direct fermentation of potato starch to ethanol by cocultures of Aspergillus niger and Saccharomyces cerevisiae.  

PubMed Central

Direct fermentation of unhydrolyzed potato starch to ethanol by monocultures of an amylolytic fungus, Aspergillus niger, and cocultures of A. niger and Saccharomyces cerevisiae was investigated. Amylolytic activity, rate and amount of starch utilization, and ethanol yields increased several-fold in coculture versus the monoculture due to the synergistic metabolic interactions between the species. Optimal ethanol yields were obtained in the pH range 5 to 6 and amylolytic activity was obtained in the pH range 5 to 8. Ethanol yields were maximal when fermentations were conducted anaerobically. Increasing S. cerevisiae inoculum in the coculture from 4 to 12% gave a dramatic increase in the rate of ethanol production, and ethanol yields of greater than 96% of the theoretical maximum were obtained within 2 days of fermentation. These results indicate that simultaneous fermentation of starch to ethanol can be conducted efficiently by using cocultures of the amylolytic fungus A. niger and a nonamylolytic sugar fermenter, S. cerevisiae.

Abouzied, M M; Reddy, C A

1986-01-01

429

Expression of exoinulinase genes in Saccharomyces cerevisiae to improve ethanol production from inulin sources.  

PubMed

To improve inulin utilization and ethanol fermentation, exoinulinase genes from the yeast Kluyveromyces marxianus and the recently identified yeast, Candida kutaonensis, were expressed in Saccharomyces cerevisiae. S. cerevisiae harboring the exoinulinase gene from C. kutaonensis gave higher ethanol yield and productivity from both inulin (0.38 vs. 0.34 g/g and 1.35 vs. 1.22 g l(-1) h(-1)) and Jerusalem artichoke tuber flour (0.47 vs. 0.46 g/g and 1.62 vs. 1.54 g l(-1) h(-1)) compared with the strain expressing the exoinulinase gene from K. marxianus. Thus, the exoinulinase gene from C. kutaonensis is advantageous for engineering S. cerevisiae to improve ethanol fermentation from inulin sources. PMID:23743955

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

2013-10-01

430

Toward a global database for the molecular typing of Saccharomyces cerevisiae strains.  

PubMed

Most of the yeast strains used in fermented beverages and foods are classified as Saccharomyces cerevisiae. However, different strains are suitable for different fermentation processes. The purpose of this work is the proposal of a standardized methodology for the molecular genotyping of S. cerevisiae strains based on polymorphisms at microsatellite loci and/or single nucleotide polymorphisms (SNPs). Single nucleotide variants in the coding region of FLO8, a key regulator of flocculation and pseudohyphae formation, were analyzed in a subset of Uruguayan wine strains. Polymorphism analysis at nine microsatellite loci (selected from 33 loci tested) was performed in a collection of 120 strains, mostly wine strains, from different origins. From a total of 184 different alleles scored, 50 were exclusive alleles that could identify 29 strains. Four selected microsatellite loci are located within or near genes of putative enological interest. The Uruguayan strains are highly diverse and evenly distributed in the phylogenetic reconstructions, suggesting an evolutionary history previous to human use. The Saccharomyces cerevisiae Microsatellites and SNPs Genotyping Database is presented (www.pasteur.edu.uy/yeast). Comparison of standardized results from strains coming from different settings (industrial, clinical, environmental) will provide a reliable and growing source of information on the molecular biodiversity of S. cerevisiae strains. PMID:18294198

Jubany, Sandra; Tomasco, Ivanna; Ponce de Len, Ins; Medina, Karina; Carrau, Francisco; Arrambide, Nicols; Naya, Hugo; Gaggero, Carina

2008-05-01

431

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

PubMed Central

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 with common features and across different species. The Fungal Alignment Viewer displays alignments of sequences from multiple fungal genomes, while the Sequence Similarity Query tool displays PSI-BLAST alignments of each S.cerevisiae protein with similar proteins from any species whose sequences are contained in the non-redundant (nr) protein data set at NCBI. The Yeast Biochemical Pathways tool integrates groups of genes by their common roles in metabolism and displays the metabolic pathways in a graphical form. Finally, the Find Chromosomal Features search interface provides a versatile tool for querying multiple types of information in SGD.

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

2004-01-01

432

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

433

The genome sequence of the wine yeast VIN7 reveals an allotriploid hybrid genome with Saccharomyces cerevisiae and Saccharomyces kudriavzevii origins.  

PubMed

The vast majority of wine fermentations are performed principally by Saccharomyces cerevisiae. However, there are a growing number of instances in which other species of Saccharomyces play a predominant role. Interestingly, the presence of these other yeast species generally occurs via the formation of interspecific hybrids that contain genomic contributions from both S.cerevisiae and non-S.cerevisiae species. However, despite the large number of wine strains that are characterized at the genomic level, there remains limited information regarding the detailed genomic structure of hybrids used in winemaking. To address this, we describe the genome sequence of the thiol-releasing commercial wine yeast hybrid VIN7. VIN7 is shown to be an almost complete allotriploid interspecific hybrid that is comprised of a heterozygous diploid complement of S.cerevisiae chromosomes and a haploid Saccharomyces kudriavzevii genomic contribution. Both parental strains appear to be of European origin, with the S.cerevisiae parent being closely related to, but distinct from, the commercial wine yeasts QA23 and EC1118. In addition, several instances of chromosomal rearrangement between S.cerevisiae and S.kudriavzevii sequences were observed that may mark the early stages of hybrid genome consolidation. PMID:22136070

Borneman, Anthony R; Desany, Brian A; Riches, David; Affourtit, Jason P; Forgan, Angus H; Pretorius, Isak S; Egholm, Michael; Chambers, Paul J

2012-02-01

434

Molecular genetic study of introgression between Saccharomyces bayanus and S. cerevisiae.  

PubMed

The genomic constitution of different S. bayanus strains and natural interspecific Saccharomyces hybrids has been studied by genetic and molecular methods. Unlike S. bayanus var. uvarum, some S. bayanus var. bayanus strains (the type culture CBS 380, CBS 378, CBS 425, CBS 1548) harbour a number of S. cerevisiae subtelomeric sequences: Y', pEL50, SUC, RTM and MAL. The two varieties, having 86-100% nDNA-nDNA reassociation, are partly genetically isolated from one another but completely isolated from S. cerevisiae. Genetic and molecular data support the maintaining of var. bayanus and var. uvarum strains in the species S. bayanus. Using Southern hybridization with species-specific molecular markers, RFLP of the MET2 gene and flow cytometry analysis, we showed that the non-S. cerevisiae parents are different in lager brewing yeasts and in wine hybrid strains. Our results suggest that S. pastorianus is a hybrid between S. cerevisiae and S. bayanus var. bayanus, while S. bayanus var. uvarum contributed to the formation of the wine hybrids S6U and CID1. According to the partial sequence of ACT1 gene and flow cytometry analysis, strain CID1 is a triple hybrid between S. cerevisiae, S. kudriavzevii and S. bayanus var. uvarum. PMID:16240458

Naumova, Elena S; Naumov, Gennadi I; Masneuf-Pomarde, Isabelle; Aigle, Michel; Dubourdieu, Denis

2005-10-30

435

Adenylate cyclases in yeast: a comparison of the genes from Schizosaccharomyces pombe and Saccharomyces cerevisiae.  

PubMed Central

A Schizosaccharomyces pombe gene encoding adenylate cyclase has been cloned by cross-hybridization with the Saccharomyces cerevisiae adenylate cyclase gene. The protein encoded consists of 1692 amino acids and has adenylate cyclase activity that cannot be activated by the Sa. cerevisiae RAS2 protein. Sc. pombe cyclase has a high degree of homology (approximately 60%) with the catalytic domain of Sa. cerevisiae cyclase precisely mapped by a gene-deletion analysis. A 25-40% identity is observed throughout the middle segments of approximately 1000 residues of both cyclases, large parts of which are composed of repetitions of a 23-amino acid motif similar to those found in human glycoproteins, Drosophila chaoptin, and Toll gene product. However, a segment corresponding to the NH2-terminal 620 residues of Sa. cerevisiae cyclase appears lost from Sc. pombe cyclase, and the COOH-terminal 140 residues are not well conserved between the two yeast species. Deletions involving the COOH-terminal residues of Sa. cerevisiae cyclase cause loss of activation by the RAS2 protein. These results suggest that Sc. pombe cyclase may have lost the ability to interact with RAS proteins by the loss of a regulatory site. Images

Yamawaki-Kataoka, Y; Tamaoki, T; Choe, H R; Tanaka, H; Kataoka, T

1989-01-01

436

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

PubMed Central

Efficient degradation of cellulosic biomass requires the synergistic action of the cellulolytic enzymes endoglucanase, cellobiohydrolase, and ?-glucosidase. Although there are many reports describing consolidation of hydrolysis and fermentation steps using recombinant Saccharomyces cerevisiae that express cellulolytic enzymes, the efficiency of cellulose degradation has not been sufficiently improved. Although the yeast S. cerevisiae cannot take up cellooligosaccharide, some fungi can take up and assimilate cellooligosaccharide through a cellodextrin transporter. In this study, a S. cerevisiae strain co-expressing genes for several cell surface display cellulases and the cellodextrin transporter was constructed for the purpose of improving the efficiency of direct ethanol fermentation from phosphoric acid swollen cellulose (PASC). The cellulase/cellodextrin transporter-coexpressing strain produced 1.7-fold more ethanol (4.3g/L) from PASC during a 72-h fermentation than did a strain expressing cellulase only (2.5g/L). Direct ethanol production from PASC by the recombinant S. cerevisiae strain was improved by co-expression of cellulase display and cellodextrin transporter genes. These results suggest that cellulase- and cellodextrin transporter-co-expressing S. cerevisiae could be a promising technology for efficient direct ethanol production from cellulose.

2013-01-01

437

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.

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

1985-01-01

438