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1
Wirth, Bénédicte. "Dynamique et évolution d'ORFs dupliquées chez les levures hémiascomycètes : Etude de la famille multigénique DUP." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. http://www.theses.fr/2006STR13070.
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Vázquez, González Jennifer. "Antioxidant effect of melatonin on Saccharomyces and non-Saccharomyces wine yeasts." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/461155.
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La melatonina (N-acetil-5 metoxytryptamine) que es sintetitza a partir de triptòfan, es forma durant la fermentació alcohòlica, no obstant el seu paper en el llevat és desconegut. Aquest estudi va utilitzar espècies de Saccharomyces i no Saccharomyces per avaluar els possibles efectes antioxidants de melatonina. Es va avaluar la resistència al H2O2, la producció d’espècies reactives d'oxigen, la peroxidació lipídica, l'activitat catalasa i a la composició lipídica (àcids grassos, fosfolípids i esterols) tant en llevats de Saccharomyces com no-Saccharomyces. A més, a S. cerevisiae es va avaluar el contingut de glutatió reduït i oxidat, es va quantificar la melatonina endògena i es va realitzar un assaig transcriptòmic. Els resultats van mostrar que els llevats que contenen àcids grassos insaturats com els àcids linoleic o linolènic són més tolerants a l'estrès oxidatiu. Per altra banda, la suplementació amb melatonina va facilitar que les cèl·lules fessin front a possibles estressos futurs. Tanmateix, quan les cèl·lules van ser sotmeses a estrès oxidatiu induït per H2O2, la melatonina va poder mitigar parcialment el dany cel·lular reduint la producció de ROS, la peroxidació de lípids i el glutatió oxidat a la vegada que augmentava el glutatió reduït i la viabilitat cel·lular. L`anàlisi de transcriptòmica va demostrar que la melatonina és capaç de modular la resposta a l'estrès oxidatiu a nivell transcripcional. Els resultats demostren que la melatonina pot actuar com antioxidant tant en llevats Saccharomyces com en no-Saccharomyces.La melatonina (N-acetil-5 metoxytryptamine) que se sintetiza a partir del triptófano, se forma durante la fermentación alcohólica, no obstante su papel en la levadura es desconocido. Este estudio utilizó especies de Saccharomyces y no Saccharomyces para evaluar los posibles efectos antioxidantes de la melatonina. Se evaluó la resistencia al H2O2, la producción de especies reactivas de oxígeno, la peroxidación lipídica, la actividad catalasa y la composición lipídica (ácidos grasos, fosfolípidos y esteroles) tanto en levaduras de Saccharomyces como no-Saccharomyces. Además, en S. cerevisiae se evaluó el contenido de glutatión reducido y oxidado, se cuantificó la melatonina endógena y se realizó un ensayo transcriptómico. Los resultados mostraron que las levaduras que contienen ácidos grasos insaturados como los ácidos linoleico o linolénico son más tolerantes al estrés oxidativo. Por otra parte, la suplementación con melatonina facilitó que las células hicieran frente a posibles estreses futuros. Sin embargo, cuando las células fueron sometidas a estrés oxidativo inducido por H2O2, la melatonina pudo mitigar parcialmente el daño celular reduciendo la producción de ROS, la peroxidación de lípidos y el glutatión oxidado a la vez que aumentaba el glutatión reducido y la viabilidad celular. El analisis de transcriptómica demostró que la melatonina es capaz de modular la respuesta al estrés oxidativo a nivel transcripcional. Los resultados demuestran que la melatonina puede actuar como antioxidante tanto en levaduras Saccharomyces como no-Saccharomyces.
Melatonin (N-acetyl-5 methoxytryptamine) which is synthesized from tryptophan, is formed during alcoholic fermentation, though its role in yeast is unknown. This study employed Saccharomyces and non-Saccharomyces species to evaluate the possible antioxidant effects of melatonin. Resistance to H2O2, reactive oxygen species, lipid peroxidation, catalase activity and lipid composition (fatty acids, phospholipids and sterols) were evaluated in both Saccharomyces and non-Saccharomyces yeasts. Furthermore, cell viability, reduced and oxidized glutathione levels, endogenous melatonin levels as well as transcriptomics study were assessed in S. cerevisiae. Results showed that non-Saccharomyces yeast containing unsaturated fatty acids such as linoleic or linolenic acids are more tolerant to oxidative stress. Melatonin supplementation enables cells to resist better further stresses. However, when cells were subjected to oxidative stress induced by H2O2, melatonin was able to partially mitigate cell damage by decreasing ROS production, lipid peroxidation and oxidized glutathione and increasing reduced glutathione and viability. Transcriptomics assays showed that melatonin is able to modulate the oxidative stress response at transcriptional level. The findings demonstrate that melatonin can act as antioxidant in both Saccharomyces and non-Saccharomyces yeasts.
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Serra, Audrey. "Production d'hybrides saccharomyces cerevisiae x saccharomyces uvarum : contraintes physiologiques et procédé." Toulouse, INPT, 2004. http://www.theses.fr/2004INPT006G.
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La maîtrise des procédés fermentaires a largement contribué à l'essor de la pratique du levurage en vinification. Toutefois, dans un souci de respect et de préservation des spécificités de chaque région viticole, de nouvelles souches de levures sont sélectionnées. Ainsi nous nous intéressons dans ce travail à l'étude de souches hybrides S. Cerevisiae x S. Uvarum et plus particulièrement dans l'optique de leur production industrielle sous forme de levures sèches actives. Tout d'abord, les caractéristiques physiologiques de la souche parentale S. Uvarum nécessaires pour la conduite d'une production de biomasse ont été identifiées. Par ailleurs, une perte de viabilité assez atypique chez une levure a été décelée sous certaines conditions opératoires. Puis après une étude comparative des souches hybrides et parentales, notamment en ce qui concerne leurs potentialités fermentaires, les modalités pour la production optimale d'un hybride ont été abordées. La détermination de deux profils d'apport du substrat, dont la validité dépend de la concentration en sucre dans l'alimentation et des souches employées, ainsi que l'accumulation de tréhalose intracellulaire en constituent les paramètres établis. Ces parmètres clé du procédé ont ensuite été confirmés par des productions de biomasse sous forme de levures sèches actives à une échelle pilote.
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James, Allan. "A genetic analysis of sulfate transporters in Saccharomyces cerevisiae and Saccharomyces pastorianus." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/1525.
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Schorling, Stefan. "Ceramidsynthese in Saccharomyces cerevisiae." Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-3658.
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Deans, Karen. "Ageing of Saccharomyces cerevisiae." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/663.
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Messias, Susana Isabel Serra. "Caraterização dos polissacarídeos da parede celular das leveduras Saccharomyces cerevisiae e Saccharomyces pastorianus." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17874.
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Mestrado em Bioquímica - Bioquímica AlimentarA indústria cervejeira usa diferentes espécies de leveduras Saccharomyces para a produção de cerveja. As leveduras são normalmente reutilizadas em 3-7 ciclos fermentativos e em seguida, são descartadas, sendo designado como levedura excedentária da cerveja (BSY). A BSY é um dos maiores subprodutos resultantes da indústria cervejeira e é fonte de polissacarídeos, nomeadamente glucanas, manoproteínas e quitina, provenientes da parede celular. No presente trabalho foram analisados os polissacarídeos das leveduras S. cerevisiae com 1 e 3 ciclos fermentativos e S. pastorianus com 2 e 6 ciclos fermentativos. Os polissacarídeos da parede celular das leveduras foram extraídos sequencialmente recorrendo à extração com água a 100 ºC e à extração aquosa assistida por micro-ondas (MWE) a 180 ºC. A extração com água quente permitiu extrair os polissacarídeos da superfície da parede celular que, no caso da S. cerevisiae, são constituídos essencialmente por resíduos de glucose em ligação (1→4) e, no caso da S. pastorianus são constituídos por resíduos de manose em ligação terminal, (1→2)-Man e (1→2,6)-Man. Os extratos solúveis da MWE, de S. cerevisiae são ricos em (1→4)-Glc e os da S. pastorianus são ricos em (1→2)-Man e (1→2,6)-Man. O resíduo insolúvel é composto por (1→4) e (1→3) glucanas. Os resíduos de glucose em ligação (1→4) foram sensíveis à hidrólise com α-amilase e com celulase, permitindo inferir a presença de resíduos com configuração anomérica α e β. Por microscopia eletrónica de varrimento verificou-se que a estrutura tridimensional das leveduras se mantém no resíduo após extração aquosa dos polissacarídeos. Uma potencial valorização deste resíduo poderá ser como microcápsula para a incorporação de compostos bioativos na área alimentar ou clínica. A levedura excedentária da cerveja apresenta grande variabilidade dependendo da estirpe/espécie da levedura e ainda do número de ciclos fermentativos a que está sujeita. Os extratos solúveis de MWE de S. cerevisiae são fonte de glucose em ligação (1→3), quando provenientes de um baixo número de reutilizações, e/ou ligação (1→4), se provenientes de um elevado número de reutilizações. As S. pastorianus são fonte de manoproteínas.
Beer industry uses different Saccharomyces yeast species, which are reused during 3-7 fermentative cycles. When discarded, they are named brewer’s spent yeast (BSY). BSY is one of the major by-products resultant of brewery industry and it is a source of glucan, mannoprotein and chitin components of yeast cell wall polysaccharides. In the present work, the cell wall polysaccharides of S. cerevisiae with 1 and 3 fermentative cycles and S. pastorianus with 2 and 6 fermentative cycles were analyzed. Cell wall polysaccharides were sequentially extracted with water at 100 ° C and with microwave assisted water extraction (MWE) at 180 ° C. The hot water extraction allowed to obtain the cell wall surface polysaccharides. Extracted S. cerevisiae polysaccharides were mainly constituted by (1→4) linked glucose and S. pastorianus ones were constituted by terminally-linked mannose, (1→2)-Man and (1→2,6)-Man. S. cerevisiae MWE extracts were enriched in (1→4)-Glc while MWE extracts of S. pastorianus were rich in (1→2)-Man e (1→2,6)-Man. The insoluble residue was composed mainly of (1→ 4) and (1→ 3) glucan. The (1→4) linked glucose was hydrolysed by amylase and cellulase, allowing to infer the presence of α and β anomeric configurations. The residue that remain after the extraction of the polysaccharides was found by scanning electron microscopy, to maintain the three dimensional structure of the yeast. This residue can be valued as a microcapsule for the incorporation of bioactive compounds in food or clinical applications. Depending on the number of yeast reutilizations, MWE extracts of S. cerevisiae are a source of (1→3)-glucans or (1→4)-glucans, while MWE extracts of S. pastorianus are a source of mannoproteins. As BSY showed a high variability depending on the yeasts strain/ species and reutilization, able to be recovered by MWE.
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Ericson, Elke. "High-resolution phenomics to decode : yeast stress physiology /." Göteborg : Göteborg University, Dept. of Cell and Molecular Biology, Faculty of Science, 2006. http://www.loc.gov/catdir/toc/fy0707/2006436807.html.
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Eriksson, Peter. "Identification of the two GPD isogenes of saccharomyces cerevisiae and characterization of their response to hyper-osmotic stress." Göteborg : Chalmers Reproservice, 1996. http://catalog.hathitrust.org/api/volumes/oclc/38202006.html.
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Soden, Alison. "The fermentation properties of non-Saccharomyces wine yeasts and their interaction with Saccharomyces cerevisiae /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phs679.pdf.
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Thesis (Ph.D.)-- University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999.Errata slip inserted on back end-paper. Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1999. Bibliography: leaves 106-125.
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Pratt, Elizabeth Stratton. "Genetic and biochemical studies of Adr6, a component of the SWI/SNF chromatin remodeling complex /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/10288.
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Kerkmann, Katja. "Die genomweite Expressionsanalyse von Deletionsmutanten der Gene NHP6A/B und CDC73 in der Hefe S.cerevisiae." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961961651.
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Harder, Andreas. "Identifizierung stresssensitiver Proteine für die Medizin und Lebensmitteltechnologie aus dem Proteom von Saccharomyces cerevisiae." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962142816.
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Bellahn, Inga. "Biochemische Charakterisierung vakuolärer Vesikel aus Saccharomyces cerevisiae." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965643484.
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Jestel, Anja. "Strukturelle Charakterisierung des Calpastatin und Untersuchung eines ATP-abhängigen Peptidtransports in S. cerevisiae." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966507193.
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Jawich, Dalal Strehaiano Pierre Lteif Roger. "Étude de la toxicité de pesticides vis-à-vis de deux genres de levures approche cinétique et moléculaire /." Toulouse : INP Toulouse, 2006. http://ethesis.inp-toulouse.fr/archive/00000329.
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Schauen, Matthias. "Mitochondriale Transportproteine in Saccharomyces cerevisiae." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965029379.
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Schulze, Ulrik. "Anaerobic physiology of Saccharomyces cerevisiae /." Online version, 1995. http://bibpurl.oclc.org/web/20903.
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Greig, Duncan. "Sex, species and Saccharomyces cerevisiae." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301401.
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Payne, Thomas. "Protein secretion in Saccharomyces cerevisiae." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438772.
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Augustová, Kamila. "Taxonomické zařazení kvasinek rodu Saccharomyces." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216792.
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The theoretical part discusses the yeasts and their taxonomic classification using traditional methods and using modern methods. Detail the work is concerned with descriptions of modern molecular-biology methods. The practical part was analyzed DNA by PCR-fingerprinting (rep-PCR) type of yeasts, which we received from the CCY and subsequent analysis of yeast samples obtained from grape musts. One of the grape must was obtained in 2009 (white grape variety) and the second in 2010 (red grape variety). Both grape musts come as integrated vineyards and organic. Grape musts samples were obtained from the winery Holánek from Ivaň. The cross-comparison of images PCR-fingerprint type yeasts and yeasts PCR-fingerprint samples using BioNumerics was to evaluate the results and conclude that the diversity of yeast flora in grape must.
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Paulo, Jorge Fernando Ferreira de Sousa. "mRNA mistranslation in Saccharomyces cerevisiae." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/7775.
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Mestrado em Biologia Molecular e CelularThe genetic code is defined as a series of biochemical reactions that establish the cellular rules that translate DNA into protein information. It was established more than 3.5 billion years ago and it is one of the most conserved features of life. Over the years, several alterations to the standard genetic code and codon ambiguities have been discovered in both prokaryotes and eukaryotes, suggesting that the genetic code is flexible. However, the molecular mechanisms of evolution of the standard genetic code and the cellular role(s) of codon ambiguity are not understood. In this thesis we have engineered codon ambiguity in the eukaryotic model Sacharomyces cerevisiae to clarify its cellular consequences. As expected, such ambiguity had a strong negative impact on growth rate, viability and protein aggregation, indicating that it affects fitness negatively. However, it also created important selective advantages in certain environmental conditions, suggesting that it has the capacity to increase adaptation potential under environmental variable conditions. The overall negative impact of genetic code ambiguity on protein aggregation and cell viability, suggest that codon ambiguity may have catastrophic consequences in multicellular organisms. In particular in tissues with low cell turnover rate, namely in the brain. This hypothesis is supported by the recent discovery of a mutation in the mouse alanyl-tRNA synthetase which creates ambiguity at alanine codons and results in rapid loss of Purking neurons, neurodegeneration and premature death. Therefore, genetic code ambiguity can have both, negative or positive outcomes, depending on cell type and environmental conditions.
O código genético pode ser definido como uma série de reacções bioquímicas que estabelecem as regras pelas quais as sequências nucleotídicas do material genético são traduzidas em proteínas. Apresenta um elevado grau de conservação e estima-se que tenha tido a sua origem há mais de 3.5 mil milhões de anos. Ao longo dos últimos anos foram identificadas várias alterações ao código genético em procariotas e eucariotas e foram identificados codões ambíguos, sugerindo que o código genético é flexível. Contudo, os mecanismos de evolução das alterações ao código genético são mal conhecidos e a função da ambiguidade de codões é totalmente desconhecida. Nesta tese criámos codões ambíguos no organismo modelo Saccharomyces cerevisiae e estudámos os fenótipos resultantes de tal ambiguidade. Os resultados mostram que, tal como seria expectável, a ambiguidade do código genético afecta negativamente o crescimento, viabilidade celular e induz a produção de agregados proteicos em S. cerevisiae. Contudo, tal ambiguidade também resultou em variabilidade fenótipica, sendo alguns dos fenótipos vantajosos em determinados condições ambientais. Ou seja, os nossos dados mostram que a ambiguidade do código genético afecta negativamente a capacidade competitiva de S. cerevisiae em meio rico em nutrientes, mas aumenta a sua capacidade adaptativa em condições ambientais variáveis. Os efeitos negativos da ambiguidade do código genético, nomeadamente a agregação de proteínas, sugerem que tal ambiguidade poderá ser catastrófica em organismos multicelulares em que a taxa de renovação celular é baixa. Esta hipótese é suportada pela recente descoberta de uma mutação na alaniltRNA sintetase do ratinho que induz ambiguidade em codões de alanina e resulta numa forte perda de neurónios de Purkinge, neurodegeneração e morte prematura. Ou seja, a ambiguidade do código genético pode ter consequências negativas ou positivas dependendo do tipo de células e das condições ambientais.
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Tsai, Isheng Jason. "Population genomics of Saccharomyces yeasts." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/4361.
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This thesis examines genome-wide polymorphisms amongst 20 strains of Saccharomyces paradoxus, a yeast strain which has recently emerged as a model organism for population genetic studies. Three major studies are included in this thesis. The first study attempts to quantify the life cycle of yeast undergoing different modes of reproduction in nature. Measures of mutational and recombinational diversity are used to make two independent estimates of the population size. In an obligatory sexual population these estimates should be approximately equal. Instead, there is a discrepancy of about three orders of magnitude, indicating that S. paradoxus goes through one sexual cycle once in every ~1,000 asexual generations. This study illustrates the utility of population genomic data in quantifying the life cycles of organisms undergoing different modes of reproduction. Second, a map showing the distribution of rates of population recombination along chromosome III of S. paradoxus is presented. Several regions of very high recombination (hotspots) are identified in chromosome III. Comparison of hotspot regions between S. paradoxus and S. cerevisiae shows evidence of conservation of recombination hotspot regions. I argue that these observations reflect the weak impact of recombination due to the reduced frequency of sex of yeasts in nature. Recombination rates correlate with GC content, consistent with various studies in yeasts and humans, but there is no correlation with diversity or divergence. In addition, regions of extremely high recombination (hotspots) show an increased rate of GC→AT than rest of the chromosome. The reason for this is not clear at present ii Finally, a catalogue of polymorphisms within each population, and divergences between the two populations of S. paradoxus is presented. Tests of selection on the chromosomal sequence of S. paradoxus suggest a predominant mode of purifying selection. At least a third of mutations in synonymous sites and ~90% of mutations in replacement sites are removed by purifying selection. We estimate that around 12-31% of replacement mutations are deleterious in S. paradoxus, and that the average selection strength acting on these mutations is 1%. I also present a summary of data and subsequent analyses from the Saccharomyces Genome Resequencing Project (SGRP). Population genetic measures are applied to data using different basecalling quality cutoffs. From the results I recommend that at least a quality score of 40 is necessary to achieve the confidence required in data to be used in population genomic analyses.
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Kim, Jae-hyun. "Chromosome segregation in Saccharomyces cerevisiae /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Caponigro, Giordano Michael. "mRNA decay in Saccharomyces cerevisiae." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/187472.
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mRNA decay is an important step in the control of gene expression. To study mRNA degradation I have exploited the genetic, biochemical, and molecular tools available in Saccharomyces cerevisiae. These studies provided insight into the signals within individual transcripts which specify their half-lives, the various mechanisms by which mRNAs are degraded, and the trans-acting factors which both perform and control nucleolytic events. I identified a 65 nucleotide segment from the coding region of the unstable MATɑl mRNA which was capable of targeting both the MATɑl and stable PGKI transcripts for rapid degradation. This "instability element" was divided into two parts, one located in the first 33, and the second in the latter 32, nucleotides. The first part could be functionally replaced by different mRNA sequences containing rare codons, and while unable to promote mRNA decay by itself, enhanced degradation mediated by the second part. I determined that the MATɑl Instability Element (MIE) targets mRNAs for rapid degradation by increasing the rates of two nucleolytic steps in a pathway of mRNA decay common to several stable and unstable yeast transcripts. The initial step in this pathway is shortening of the poly(A) tail of an mRNA. Subsequently, mRNAs are decapped, after which the transcript body is degraded in a 5' to 3' exonucleolytic manner. The MIE promotes decay of the MATɑl mRNA through an increase in its decapping rate. In contrast, PGKI mRNA decay was stimulated through an increase in its rate of deadenylation. The observation that the poly(A) tail must be removed prior to mRNA decapping suggests that the poly(A) tail inhibits decapping. I determined that the major poly(A)binding protein (Pablp) is required for the inhibition of decapping mediated by the poly(A) tail. Pablp is also required for normal deadenylation rates. Pablp therefore affects mRNA decapping and deadenylation, the two rate determining steps in a common pathway of mRNA decay. Determining how Pablp, and additional trans-acting factors, exert influence over both decapping and deadenylation will provide a greater understanding of the basis of differential rates of mRNA degradation.
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Dunckley, Travis Lee. "mRNA decapping in Saccharomyces cerevisiae." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289165.
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The major pathway of mRNA degradation in yeast occurs through deadenylation, decapping and subsequent 5' to 3' exonucleolytic decay of the transcript body. The products of the DCP1 and DCP2 genes are required for mRNA decapping. DCP1 encodes a conserved mRNA decapping enzyme. Dcp2p is a highly conserved protein that is required for the activation of Dcp1p. The Dcp2p contains a functional Muff motif that is required for its decapping function, suggesting that Dcp2p encodes a pyrophosphatase. These results suggest that Dcp2p hydrolyzes a specific pyrophosphate bond that either directly activates Dcp1p or removes a specific inhibitor of Dcp1p. In addition to Dcp2p, several additional proteins were identified that influence mRNA decapping. Edc1p and Edc2p are related proteins whose overexpression suppressed conditional mutations in dcp1 and dcp2, respectively. The Edc1 protein interacts in vivo with Dcp1p and Dcp2p. Based on similar genetic data for EDC1 and EDC2, the Edc2p also likely interacts directly with the mRNA decapping machinery. Edc1p and Edc2p may function to activate transitions in the decapping complex that lead to the Dcp2p-dependent activation of Dcp1p. The SBP1 protein was identified as an overexpression suppressor of a conditional dcp2 allele, termed dcp2-7. SBP1 overexpression also suppressed a conditional allele of the decapping enzyme (dcp1-2). In addition, the sbp1Delta was found to partially suppress the decapping defect of the dcp2-7 allele. This suggests that SBP1, which is a highly conserved RNA binding protein related to nucleolin, may influence the assembly or organization of the mRNP. Lastly, loss of function mutations in the previously uncharacterized IDC1 gene were shown to stimulate decapping in the presence of the dcp2-7 mutation. This suggests that the wild-type Idc1p inhibits mRNA decapping. Interestingly, the idc1 mutations described here represent the only known loss of function mRNA decapping suppressors that are not known to influence the rate of translation initiation, suggesting a more direct role for Idc1p in the inhibition of Dcp2p function. Combined, these results indicate that mRNA decapping is a highly controlled process involving the intricate and coordinated function of multiple proteins, in addition to the Dcp1p decapping enzyme.
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Anderlund, Mikael. "Redox balancing in recombinant strains of Saccharomyces cerevisiae." Lund : University of Lund, 1998. http://books.google.com/books?id=uc5qAAAAMAAJ.
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Giroux, Mélissa. "Identification des déterminants génétiques impliqués dans la différenciation phénotypique entre Saccharomyces cerevisiae et Saccharomyces paradoxus." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29628/29628.pdf.
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L’objectif principal de cette étude était d’identifier les déterminants génétiques causant une différenciation phénotypique entre les levures Saccharomyces cerevisiae et Saccharomyces paradoxus. Ces espèces peuvent s’hybrider malgré des différences écologiques importantes, dont la capacité de croître à haute température. S. cerevisiae et l’hybride sont capables de croître à 37 °C tandis que S. paradoxus ne peut pas. L’approche qui a été utilisée est un test de complémentation. D’abord, les chromosomes de S. cerevisiae ont été enlevés un à un du génome de l’hybride, puis les gènes afin d’augmenter la résolution de l’approche. Ainsi, les chromosomes et les gènes de S. paradoxus qui ne peuvent pas complémenter ceux de S. cerevisiae, empêchant l’hybride de croître à 37 °C, ont pu être identifiés. Les résultats indiquent que la différence entre les taux de croissance de S. cerevisiae et S. paradoxus est causée par de multiples locus ayant des effets mineurs sur le phénotype.
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Chasseriaud, Laura. "Interactions entre levures Saccharomyces cerevisiae et non-Saccharomyces en vinification. : Incidence de facteurs de l’environnement." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0309/document.
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Les levures non-Saccharomyces, naturellement présentes dans les moûts, peuvent impacter positivement ou négativement la qualité des vins. Depuis quelques années, l’utilisation de cultures mixtes comme starters, associant une souche de Saccharomyces cerevisiae et une souche d’une autre espèce est proposée aux œnologues. C’est le cas du couple S. cerevisiae/Torulaspora delbrueckii. L’étude des interactions entre la souche T. delbrueckii Zymaflore Alpha et S. cerevisiae Zymaflore X5, de la société Laffort, a été réalisée. Les fermentations alcooliques ont été effectuées dans un réacteur à double compartiment permettant la séparation physique des levures tout en conservant l’homogénéité du milieu de culture. Les résultats ont mis en évidence que la séparation impacte la croissance des deux souches suggérant l’existence d’interactions de type cell-cell contact entre ces deux souches. Si une grande majorité de praticiens utilise désormais les levures sélectionnées, certains ont fait le choix de favoriser les populations autochtones de levures S .cerevisiae et de levures non-Saccharomyces. L’incidence de deux facteurs de l’environnement a été étudié sur un mélange de cinq espèces de non-Saccharomyces (T. delbrueckii, Metschnikowia spp., Candida zemplinina, Hanseniaspora uvarum, Pichia kluyveri) et de deux souches de S. cerevisiae (une à phase de latence courte, une à phase de latence longue) en cultures pures et en mélange. L’inoculation de la souche de S. cerevisiae à phase de latence longue dans un moût saturé en CO2 permet de stimuler les levures non-Saccharomyces d’intérêt (T. delbrueckii/P. kluyveri) tout en inhibant les espèces indésirables (H. uvarum, C. zemplinina)Non-Saccharomyces yeasts, naturally found in grape must, can impact wine quality positively or negatively. In recent years, the use of mixed cultures as starters (association of S. cerevisiae species and other species) such as the couple Saccharomyces cerevisiae/Torulaspora delbrueckii is proposed to winemakers. Interactions between these two species have been studied with two commercial strains, T. delbrueckii Zymaflore Alpha and S. cerevisiae Zymaflore X5 (Laffort). Alcoholic fermentations were carried out in a fermentor with double compartment allowing a physical separation of yeasts and preserving the homogeneity culture medium. The results highlighted that the physical separation impacts the growth of both strains, suggesting interactions of type cell-cell contact between these two strains. If a large majority of winemakers use selected yeasts strains, some of them chose to favor native yeasts, S. cerevisiae species and non- Saccharomyces species. The impact of two environmental factors was investigated on five non-Saccharomyces species (T. delbrueckii, Metschnikowia spp., Candida zemplinina, Hanseniaspora uvarum, Pichia kluyveri) and two strains of S. cerevisiae (one with short fermentation lag phase, one with long fermentation lag phase), in pure and mixed cultures. The inoculation with S. cerevisiae with a long fermentation lag phase in a must saturated with CO2 allowed to stimulate some of non-Saccharomyces which present an interest in winemaking (T. delbrueckii/P. kluyveri) and inhibit the undesirable ones (H. uvarum, C. zemplinina)
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Jawich, Dalal. "Etude de la toxicité de pesticides vis-à-vis de deux genres de levures : approche cinétique et moléculaire." Phd thesis, Toulouse, INPT, 2006. http://oatao.univ-toulouse.fr/7481/1/jawich.pdf.
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L'effet de plusieurs pesticides envers Saccharomyces cerevisiae et Metschnikowia pulcherrima a été évalué. Une étude de la cytotoxicité et la génotoxicité du penconazole en fonction des conditions de culture et du stade métabolique a été effectuée. Le penconazole inhibe les cinétiques de croissance et de fermentation des deux levures en cas d'exposition dès l'inoculation aux concentrations résiduelles faibles (0,2-2 ppm), M. pulcherrima est plus sensible ; des adduits à l'ADN ont été détectés dans les cultures contaminées durant la phase exponentielle. Ces résultats ont été validés en testant notre système expérimental levurien vis-à-vis du benzo(a)pyrène et de l'aflatoxine B1 (0,2 et 2 ppm), deux génotoxiques de référence. Des adduits à l'ADN ont été obtenus dans toutes les cultures exposées au benzo(a)pyrène, et l'aflatoxine B1 a induit la formation d'adduits uniquement lors de son addition durant la phase exponentielle ; alors que la croissance n'a pas été altérée par aucun des deux.
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Ansell, Ricky. "Redox and osmoregulation in Saccharomyces cerevisiae the role of the two isogenes encoding NAD-dependent glycerol 3-phosphate dehydrogenase /." Göteborg : [Institute of Cell and Molecular Biology, Dept. of General and Marine Microbiology, Lundberg Laboratory, Göteborg University], 1997. http://catalog.hathitrust.org/api/volumes/oclc/38985539.html.
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Eberlein, Chris. "The genetic bases of ecological specialization and the effects of hybridization in a complex of incipient yeast species." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/33715.
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Il existe des millions d'espèces différentes dans le monde qui ont évolué grâce à des interactions complexes avec leur environnement. La biologie évolutive contemporaine connaît une révolution grâce au séquençage de génomes ainsi qu’au criblage et la manipulation génétique, mais l'objectif reste le même qu'il y a 160 ans: comprendre les mécanismes sous-jacents impliqués dans la spéciation. Cela peut être réalisé en étudiant les mécanismes génétiques impliqués dans l'adaptation locale et la spécialisation écologique lors des premiers événements de spéciation. L'objectif principal de cette thèse est d'étudier les mécanismes moléculaires qui sous-tendent l'adaptation et la différenciation des populations dans un complexe de jeunes espèces de la levure Saccharomyces paradoxus, naturellement présentes dans les forêts de feuillus d'Amérique du Nord. En utilisant diverses approches, telles que la génomique des populations, la biologie expérimentale, la transcriptomique et le phénotypage à haut débit, nous (1) disséquons les bases génétiques de la spécialisation écologique et (2) étudions les effets de l’hybridation sur la divergence rapide et la spéciation. Nous documentons d’abord que la spécialisation écologique à différentes températures (un phénotype reconnu pour jouer un rôle important dans la divergence de deux principales lignées de S. paradoxus) est en partie causée par une sélection assouplie avec des compromis. Les travaux portant sur deux événements d'hybridation inter-espèces démontrent, quant à eux, un croisement entre une espèce hybride et son espèce parentale, ce qui indique que l'hybridation est probablement plus fréquente dans l'évolution des espèces qu'on ne le pensait auparavant. Nos travaux soulignent l’importance de la différenciation écologique par une sélection relaxée plutôt que par une divergence adaptative de la fixation de mutations bénéfiques. En outre, nos travaux montrent que l'hybridation dans la nature joue probablement un rôle important dans la création d'une nouvelle diversité par le biais de la ségrégation transgressive et que cela peut se répéter par des croisements incluant des espèces hybrides. Des études à venir sur des espèces jeunes et des complexes hybrides permettront de comprendre davantage les bases génétiques de la différenciation des populations, les conséquences de l'hybridation inter-espèces et de sa récurrence dans l'origine des espèces.Millions of different species inhabiting the world have evolved through complex interactions with their environment. Contemporary evolutionary biology is experiencing a revolution in genome sequencing, screening and genetic manipulation technologies. Its aim, however, remains the same as 160 years ago when pioneers like Darwin and Wallace published the first articles about the evolutionary theory: to understand the underlying mechanisms involved in speciation, because such knowledge is key to shed light into species diversification. This can be achieved by studying the genetic mechanisms involved in local adaptation and ecological specialization during early speciation events. The main objective of this work is to investigate the molecular mechanisms underlying adaptation and population differentiation in a young species complex of the budding yeast Saccharomyces paradoxus, naturally found in the North American deciduous forests. Using different approaches, such as population genomics, experimental biology, transcriptomics and high-throughput phenotyping we (1) dissect the genetic bases for ecological specialization and (2) investigate the effect of hybridization in facilitating rapid divergence and speciation. First, we document that the ecological specialization to different temperatures, a phenotype that has been previously shown to play an important role in the divergence of two main S. paradoxus lineages, is partially driven by relaxed selection with trade-offs. Second, with the work on two inter-species hybridization events, we document a back-cross between a hybrid taxa and its parental species, which highlights that hybridization is likely more common in the evolution of species than previously thought. Our work underlines the importance of ecological differentiation through relaxed selection, rather than adaptive divergence from the fixation of beneficial mutations. Additionally, our findings show that hybridization in nature likely plays an important role in creating new diversity through transgressive segregation, and that this can reiterate through crosses that include hybrid species. Studies on young species and hybrid complexes will enable to further understand the genetic bases of population differentiation and the consequences of inter-species hybridization and its recurrence in the origin of species.
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Kemp, Hilary A. "A complex of six FAR proteins required for pheromone arrest and mating /." view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3113011.
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Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 94-104). Also available for download via the World Wide Web; free to University of Oregon users.
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Strässle, Christoph A. "Modell zur Spontansynchronisation von Saccharomyces cerevisiae /." [S.l.] : [s.n.], 1988. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=8598.
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Deckers, Markus. "Charakterisierung peroxisomaler Proteine aus Saccharomyces cerevisiae." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985178043.
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Stüer, Heike. "Wahrnehmung von Biotinmangel durch Saccharomyces cerevisiae." kostenfrei, 2009. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1353/.
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Großmann, Guido. "Plasma membrane compartmentation in Saccharomyces cerevisiae." kostenfrei, 2008. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1152/.
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London, Markus Konrad Justin. "Regulation der Proteasombiogenese in Saccharomyces cerevisiae." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974673315.
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Beck, Karsten. "Das Dhh1 Protein aus Saccharomyces cerevisiae." Diss., lmu, 2002. http://nbn-resolving.de/urn:nbn:de:bvb:19-7362.
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Widlund, Per Olov Ingvar. "The Saccharomyces cerevisiae chromosomal passenger, Bir1 /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/9202.
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Thompson, C. L. "Interaction of pentamidine with Saccharomyces cerevisiae." Thesis, University of Hull, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377415.
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Reithinger, Johannes. "Membrane Protein Biogenesis in Saccharomyces cerevisiae." Doctoral thesis, Stockholms universitet, Institutionen för biokemi och biofysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-95376.
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Membranes are hydrophobic barriers that define the outer boundaries and internal compartments of living cells. Membrane proteins are the gates in these barriers, and they perform vital functions in the highly regulated transport of matter and information across membranes. Membrane proteins destined for the endoplasmic reticulum are targeted either co- or post-translationally to the Sec61 translocon, the major translocation machinery in eukaryotic cells, which allows for lateral partitioning of hydrophobic segments into the lipid bilayer. This thesis aims to acquire insights into the mechanism of membrane protein insertion and the role of different translocon components in targeting, insertion and topogenesis, using the yeast Saccharomyces cerevisiae as a model organism. By measuring the insertion efficiency of a set of model proteins, we studied the sequence requirements for Sec61-mediated insertion of an α-helical transmembrane segment and established a ‘biological hydrophobicity scale’ in yeast, which describes the individual contributions of the 20 amino acids to insertion. Systematic mutagenesis and photo-crosslinking of the Sec61 translocon revealed key residues in the lateral gate that modulate the threshold hydrophobicity for membrane insertion and transmembrane segment orientation. Further, my studies demonstrate that the translocon-associated Sec62 is important not only for post-translational targeting, but also for the insertion and topogenesis of moderately hydrophobic signal anchor proteins and the C-terminal translocation of multi-spanning membrane proteins. Finally, nuclearly encoded mitochondrial membrane proteins were found to evade mis-targeting to the endoplasmic reticulum by containing short C-terminal tails.At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 4: Manuscript; Paper 5: Manuscript
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Gray, Allison J. "Saccharomyces boulardii and the small intestine." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282154.
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Spalding, A. C. "Host-plasmid interactions in Saccharomyces cerevisiae." Thesis, University of Kent, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383082.
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Jenkins, F. "Development of thermotolerance in Saccharomyces cerevisiae." Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234851.
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Pearce, Amanda K. "Regulation of glycolysis in Saccharomyces cerevisiae." Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301297.
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This thesis extends the work of Crimmins (1995) on the control of glycolytic flux in yeast by the enzymes 6-phosphofructo-1-kinase and pyruvate kinase (Pyk1p). This study also examines the influence of Pf1kp and Pyk1p upon yeast resistance to the weak acid preservative, benzoic acid. In Saccharomyces cerevisiae, Pyk1p is encoded by PYK1, and the α and β subunits of Pf1kp are encoded by PFK1 and PFK2, respectively. To test the influence of these genes upon glycolytic control, an isogenic set of S. cerevisiae mutants were utilised in which PYK1, PFK1 and PFK2 expression is dependent on the PGK1 promoter. Increased Pf1k levels had little effect upon rates of glucose utilisation or ethanol production during fermentative growth. However, overexpressing Pyk1p resulted in an increased growth rate and an increase in glycolytic flux. This suggests that Pyk1p, but not Pf1kp, exerts some degree of control over the glycolytic flux under these conditions. The effects of reducing Pf1kp and Pyk1p levels were also studied by placing PYK1, PFK1 and PFK2 under the control of the weak PGK1Δuas promoter. The double Pf1kp mutant showed no significant changes in doubling time, ethanol production or glucose consumption. However, a mutant with a 3-fold reduction ion Pyk1p levels displayed slower growth rates and reduced glycolytic flux. In addition, there was an imbalance in the carbon flow in this mutant, with reductions in ethanol and glycerol production evident, along with increased TCA cycle activity. Hence, while Pf1kp levels did not affect cell physiology significantly under the conditions studied, reduced Pyk1p levels seemed to disturb glycolytic flux and carbon flow. Decreased Pf1kp levels caused an increase in the sensitivity of yeast cells to benzoate, whereas the Pyk1p mutant was not affected. This confirmed that benzoic acid specifically inhibits Pf1kp rather than glycolysis in general.
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Hatton, Lee S. "Gluconeogenic gene regulation in Saccharomyces cerevisiae." Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387524.
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The yeast FBP1 and PCK1 genes and the gluconeogenic enzymes that they encode, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase, are subject to multiple levels of regulation by glucose. It has been reported that transcriptional repression of these genes is exceptionally sensitive to glucose, being triggered by glucose concentrations of less than 0.005% (0.25 mM). It was shown here that in addition at transcriptional repression, the FBP1 and PCK1 and mRNAs are destabilised about 2-fold upon addition of the same low levels of glucose. Low levels of the fermentable sugars fructose or sucrose also stimulated this effect but galactose did not. This destabilisation was lost in a triple hxk1, hxk2, glk1 mutant, but was not triggered by addition of 2-deoxyglucose. The data suggests that sugar phosphorylation and further metabolism of glucose is required to trigger this response. Analysis of metabolic mutants showed that mutations in the upper part of the glycolytic pathway abolish the destabilisation of the FBP1 mRNA. Differences were shown to exist between the regulatory pathways that mediate glucose-stimulated mRNA decay and transcriptional repression. Models which might account for the mechanisms by which rapid decay of the gluconeogenic mRNAs is triggered are discussed. A strategy based on gene fusions with the stable PGK1 mRNA was designed in order to map cis-acting regions which influence PCK1 mRNA stability. A fusion mRNA containing the PCK1 mRNA protein coding region was not destabilised upon addition of low levels of glucose. It was therefore suggested that glucose-stimulated mRNA decay might in some way be dependent upon translation initiation via an interaction with the 5'-leader.
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Rowley, Neil K. "Studies on the Saccharomyces cerevisiae genome." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361615.
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Zealey, Gavin Ross. "Plasmid copy number in Saccharomyces cerevisiae." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333232.
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Studies were made of 2 mum based chimaeric plasmid copy number in Saccharomyces cerevisiae. A plasmid (pAYE56) containing three selectable genes in yeast (yeast LEU2, bacterial CAT and HSV-1 - TK) was constructed to reflect changes in copy number. Yeast transformants could be grown under three selection regimes and plasmid copy number estimated. During selective growth for the LEU2 gene there are about 20 plasmids per cell. This increases to about 100 during selective growth for the TK gene and furthermore the copy number can be controlled by the stringency of selection. Simultaneous selection for the TK and CAT genes may lead to a further increase (160 copies). Two models are proposed to account for these increases. The amplification model proposes plasmid replication without cell growth whilst the selection model suggests that plasmid copy number varies greatly in a population of transformants and cells with a high copy number are selected for growth under the TK/CAT selection conditions. Whilst the mechanism of copy number increase is unclear, an attempt was made to relate the expression of a heterologous gene (Human alpha2-IFN) to gene dosage using the promotion and secretion signals of the alpha-factor gene. Production of intracellular alpha2-IFN was unaffected by copy number whilst secreted material showed a 100 fold increase over a ten fold increase in gene dosage. Attempts were made to isolate plasmid copy number mutants. After mutagenesis (of cells or plasmid) transformants were selected under conditions for simultaneous over-expression of the TK and CAT genes. Mutants capable of growth under these conditions were obtained. In one group the mutant phenotype was lost upon curing but did not return upon retransformation. In a second group a chromosomal mutation was isolated. Plasmid copy number estimates indicated that this was unchanged however. Alternative strategies are discussed for the isolation of mutants.
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Gimeno, Carlos Joaquín. "Characterization of Saccharomyces cerevisiae pseudohyphal development." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/33506.
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