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1
Yap, Nicholas Andrew. "The sensitivity of yeasts to killer yeast toxins : with focus on the killer yeast Pichia membranifaciens /". Title page, abstract and contents only, 2000. http://web4.library.adelaide.edu.au/theses/09APSP/09apspy25.pdf.
Testo completo
2
Brady, Dean. "Bioaccumulation of metal cations by yeast and yeast cell components". Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004107.
Testo completoAbstract (sommario):
The aim of the project was to determine whether a by-product of industrial fermentations, Saccharomyces cerevisiae, could be utilized to bioaccumulate heavy metal cations and to partially define the mechanism of accumulation. S. cerevisiae cells were found to be capable of accumulating Cu²⁺in a manner that was proportional to the external Cu²⁺ concentration and inversely proportional to the concentration of biomass. The accumulation process was only minimally affected by temperature variations between 5 and 40°C or high ambient concentrations of sodium chloride. The accumulation process was however considerably affected by variations in pH, bioaccumulation being most efficient at pH 5 - 9 but becoming rapidly less so at either extreme of pH. Selection for copper resistant or tolerant yeast diminished the yeast's capacity for Cu²⁺ accumulation. For this and other reasons the development of heavy metal tolerance in yeasts was deemed to be generally counterproductive to heavy metal bioaccumulation. The yeast biomass was also capable of accumulating other heavy metal cations such as c0²⁺ or Cd²⁺. The yeast biomass could be harvested after bioaccumulation by tangential filtration methods, or alternatively could be packed into hollow fibre microfilter membrane cartridges and used as a fixed-bed bioaccumulator. By immobilizing the yeast in polyacrylamide gel and packing this material into columns, cu²⁺, C0²⁺ or Cd²⁺ could be removed from influent aqueous solutions yielding effluents with no detectable heavy metal, until breakthrough point was reached. This capacity was hypothesized to be a function of numerous "theoretical plates of equilibrium" within the column. The immobilized biomass could be eluted with EDTA and recycled for further bioaccumulation processes with minor loss of bioaccumulation capacity. Yeast cells were fractionated to permit identification of the major cell fractions and molecular components responsible for metal binding. Isolation of the yeast cell walls permitted investigation of their role in heavy metal accumulation. Although the amino groups of chitosan and proteins, the carboxyl groups of proteins, and the phosphate groups of phosphomannans were found to be efficient groups for the accumulation of copper, the less effective hydroxyl groups of the carbohydrate polymers (glucans and mannans) had a similar overall capacity for copper accumulation owing to their predominance in the yeast cell wall. The outer (protein-mannan) layer of the yeast cell wall was found to be a better Cu²⁺ chelator than the inner (chitinglucan) layer. It appeared that the physical condition of the cell wall may be more important than the individual macromolecular components of the cell wall in metal accumulation. It was apparent that the cell wall was the major, if not the sole contributor to heavy metal accumulation at low ambient heavy metal concentrations. At higher ambient metal concentrations the cytosol and vacuole become involved in bioaccumulation. Copper and other metals caused rapid loss of 70% of the intracellular potassium, implying permeation of the plasma membrane. This was followed by a slower "leakage" of magnesium from the vacuole which paralleled Cu²⁺ accumulation, suggesting that it may represent some form of ion-exchange. An intracellular copper chelating agent of approximately 2 kDalton molecular mass was isolated from copper tolerant yeast. This chelator was not a metallothionein and bound relatively low molar equivalents of copper compared to those reported for metallothionein. Treatment of the biomass with hot alkali yielded two biosorbents, one soluble (which could be used as a heavy metal flocculent), and an insoluble biosorbent which could be formed into a granular product to be used in fixed-bed biosorption columns. The granular biosorbent could accumulate a wide range of heavy metal cations in a semispecific manner and could be stored in a dehydrated form indefinitely, and rehydrated when required. Bioaccumulation by live algae was investigated as an alternative to yeast based processes. Various strains of algae, of which Scenedesmus and Selenastrum were the most effective, were found to be capable of accumulating heavy metals such as Cu²⁺, Pb²⁺ and Cr³⁺.
3
Louie, Gordon V. "Structural studies of wild-type and variant yeast iso-1-cytochromes c". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30997.
Testo completoAbstract (sommario):
The crystal structure of yeast (Saccharomyces cerevisiae) iso-1- cytochrome c has been determined through molecular replacement techniques, and refined against X-ray diffraction data in the resolution range 6.0-1.23 Å to a crystallographic R-factor of 0.192. The yeast iso-1-cytochrome c molecule has the typical cytochrome c fold, with the polypeptide chain organized into five α-helices and a series of loops which serve to enclose almost completely the heme prosthetic group within a hydrophobic pocket Comparison of the structures of yeast iso-1-, tuna and rice cytochromes c shows that the polypeptide backbone fold, intramolecular hydrogen bonding, conformation of side chains and particularly packing within the heme crevice of protein groups against the heme moiety are very similar in the three proteins. Significant structural differences among the three cytochromes c can be explained by differences in amino acid sequence.
X-ray crystallographic techniques have also been used to study the effect of single-site amino acid substitutions at Phe82 and at Arg38 in iso-1-cytochrome c. The structures of the various variant iso-1-cytochromes c have been determined at nominal resolutions in the range 2.8 to 1.76 Å. Conspicuous structural perturbations in the neighborhood of the substituted side chain are evident in all of the variant proteins. In wild-type iso-1-cytochrome c, the phenyl ring of Phe82 is positioned adjacent and approximately parallel to the heme group, and occupies a non-polar cavity within the heme crevice. In the Ser82 variant, a channel extending from the surface of the molecule down into the heme crevice is created. In the Gly82 variant, the polypeptide backbone has refolded into the space formerly occupied by the phenyl ring of Phe82. Steric conflicts prevent both the phenolic ring of Tyr82 and the side chain of Ile82 from being completely accommodated within the pocket normally occupied by a phenyl ring. Substitution of alanine at position 38 causes a slight reorganization of the hydrogen bonding network in which Arg38 normally participates, and also exposes to external solvent a normally buried propionic acid group of the heme.
The altered functional properties of the position 82 variant proteins have been interpreted with respect to the observed structural perturbations. The drop in reduction potential, most notably for the Ser82 and Gly82 variants, can be explained by the elevated heme environment polarity arising from the increased access of solvent or polar protein groups to the heme pocket The reduced stability of the heme crevice, as indicated by lowered pKa's for alkaline isomerization, is likely due to the disruption of stabilizing packing forces formed by the Phe82 phenyl ring within its hydrophobic cavity. The lowered activity, in comparison to the wild-type protein and the Tyr82 variant, for electron transfer with Zn+-cytochrome c peroxidase is attributed to the loss of an aromatic group positioned adjacent to the heme group. The altered surface topography of the variant proteins (particularly the Gly82, Tyr82 and Ile82 variants) may further hinder productive complex formation between cytochrome c and its redox partners. These results suggest that the invariant Phe82 contributes in at least three ways to the proper functioning of cytochrome c. It has an important structural role in maintaining the integrity of the heme crevice and in establishing the appropriate heme environment The phenyl ring of Phe82 may also be required for efficient movement of an electron to and from the heme of cytochrome c. Finally, Phe82 may have a role in forming intermolecular interactions with enzymic redox partners of cytochrome c.Medicine, Faculty of
Biochemistry and Molecular Biology, Department of
Graduate
4
Samuels, Michael L. "Yeast stress signalling". Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368116.
Testo completo
5
Hansen, Christine S. "Construction of galactose assimilating, carotenoid producing yeasts by protoplast fusion". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27935.
Testo completoAbstract (sommario):
Protoplasts were prepared from two yeast strains P. rhodozyma (ATCC 24202) and K. fragilis (ATCC 8455). Protoplasts prepared from P. rhodozyma were facilitated by prior growth of the cells in a media containing S-(2-aminoethyl)-L-cysteine. Protoplasts from these two yeast genera were fused either by the use of electrofusion or polyethylene glycol treatment. Stable carotenoid producing cell lines were selected by growth at 30°C on yeast nitrogen base plus galactose.
Selected single fusants display taxonomic characteristics common to both genera with a cellular morphology and a carotenoid composition similar to that of P. rhodozyma.Land and Food Systems, Faculty of
Graduate
6
Nayyar, Ashima. "Yeast flocculation : understanding cell surface structure-function relationships in industrial yeast strains". Thesis, Abertay University, 2015. https://rke.abertay.ac.uk/en/studentTheses/cec13693-e667-4426-ba6c-6873e5c2b642.
Testo completoAbstract (sommario):
Adhesion properties of microorganisms are crucial for many essential biological processes such as sexual reproduction, tissue or substrate invasion, biofilm formation and cell-cell aggregation. One of such controlled forms of cellular adhesion in yeast that occurs preferentially in the liquid environments is a process of asexual aggregation of cells which is also referred to as flocculation. The timing during growth and the causes of onset of yeast flocculation are of commercial interest to the brewing industry, as flocculation can determine the degree of attenuation of the wort. Early or premature flocculation is one common causes of ‘hung’ or ‘stuck’ fermentations giving rise to sweeter beer whereas a lack or delay in flocculation can cause filtration difficulties and some problems in obtaining a bright sparkling beer; in addition, the presence of excess yeast in beer during ageing can cause off flavours due to yeast autolysis. Despite this commercial interest, limited information is available about the onset of flocculation and the various factors that may be responsible in the process. In particular, what are the signals that trigger flocculation? Adhesion properties applicable in improving yeast biotechnology are dependent directly or indirectly on characteristics of cellular surfaces, usually the outer layer of the cell wall. Change in the structure and or composition of the cell wall leads to changes in the microbial adhesion properties. Exploring more into the cell wall and studying the nanoscale structure of the yeast cell wall would thus be beneficial to augment our understanding of flocculation.
7
Milošević, Tamara. "Yeast pathology : a systemic analysis of death and aging in budding yeast". Paris 5, 2011. http://www.theses.fr/2011PA05T040.
Testo completoAbstract (sommario):
Le vieillissement et la mort font partie intégrante de la vie et jouent un rôle dans l’histoire de vie d’un organisme en influençant à la fois la structure de sa population et son évolution. Le vieillissement chez la levure a été largement étudié en observant l’espérance de vie réplicative et chronologique, alors que la mort a été décrite comme un processus similaire à la nécrose et l’apoptose. Malgré le fait que le vieillissement entraîne la mort, les organismes peuvent aussi mourir prématurément à la suite de maladies. Afin de comprendre l’étendue des changements morphologiques précédant la mort, j’ai analysé l’ensemble des 1091 mutants de gènes essentiels de la levure au niveau cellulaire. J’ai décrit de manière quantitative le caractère essentiel de chaque gène et documenté les caractéristiques phénotypiques des cellules et colonies comme une représentation vivide des changements cellulaires chez des mutants de levures avant qu’ils ne cessent de se diviser puis qu’ils ne meurent. Bien que certains phénotypes de mutants de gènes essentiels puissent être expliqués au moyen des connaissances actuelles sur les gènes en question, la complexité des modèles de mort nous montre que la mort à l’échelle cellulaire unique est très peu comprise. Néanmoins il est clair que chez la levure les symptômes résultant d’une maladie génétique diffèrent de ceux résultant du vieillissement normal de la cellule. Ce travail de recherche montre ainsi l’importance des analyses au niveau de la cellule unique de phénomènes complexes biologiques et offre un point de départ pour une exploration future des maladies endogènes et des mécanismes liés au vieillissement entraînant la mortAging and death are integral parts of life and as such play a role in individual organism’s life history, influencing at the same time the structure of population and its evolution. Aging in yeast has been extensively studied by looking at both replicative and chronological lifespans, while death of yeast cells has been described in terms of necrosis- and apoptosis-like processes. Despite the fact that aging eventually results in death, organisms can also die prematurely because of the disease. In order to understand the possible repertoire of morphological changes preceding death, I have systematically analyzed all 1091 yeast essential gene mutants on the cellular level. I have quantitatively described the degree of essentiality for each essential gene, and documented the phenotypic characteristics of cells and the colonies as a vivid representation of cellular changes budding yeast mutants experience before they stop dividing and eventually die. Although some phenotypes of essential gene mutants can be explained using available knowledge about the genes in question, the complexity of dying patterns shows us that death on a single-cell level is still poorly understood. Nevertheless, it is clear that the symptoms of the genetic disease in yeast differ from the symptoms of normal yeast cell aging. This research emphasizes the importance of single-cell analysis of complex biological phenomena and offers a starting point for the future exploration of the endogenous disease- and agingrelated mechanisms that cause death
8
Day, Ngoc Bich. "The inhibition of yeast spoilage of blueberries during modified atmosphere packaging storage". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27868.
Testo completoAbstract (sommario):
Modified atmosphere packaging storage combines an atmosphere of higher carbon dioxide and lower oxygen levels than air, with chilling temperatures to extend shelf-life of fresh fruits.
In three modified atmosphere packaging storage trials, blueberries were packaged in film bags with different gas permeabilities, and stored at about 4°C. Storage of blueberries in packages of a film with intermediate gas permeability produced an aerobic atmosphere and a relatively low carbon dioxide level, resulting in rapid growth of yeast and molds on blueberries. Packaging blueberries in a film with very low gas permeability created a high carbon dioxide almost anaerobic atmosphere, which successfully inhibited yeast and mold growth on blueberries for up to eight weeks.
The possibility of yeast inhibition by antifungal compounds accumulated in blueberries stored under modified atmosphere packaging conditions was investigated by using the disk diffusion assay. The results of these assays showed the absence of antifungal activity against two Rhodotorula species, a Zygosaccharomyces species, a Cryptococcus species, a Debaryomyces species, and indicated that the inhibition of yeast growth was due to low temperature, high carbon dioxide level and anaerobic conditions. The effects of temperature and atmosphere composition were investigated by using natural flora of blueberry juice and two yeast isolates grown in sterilized juice. At 21°C, yeast growth was slow in the presence of carbon dioxide and absence of oxygen. At low temperature, yeast growth was slow in the presence of oxygen, but was inhibited in the anaerobic, high carbon dioxide environment.
It is proposed that the micro-aerobic environment of modified atmosphere packaging storage might have allowed slow desaturation of yeast membrane fatty acids which enabled yeasts to maintain membrane fluidity and function at low .temperature. Furthermore, yeast growth during storage of modified atmosphere packaged blueberries may be affected by low temperature and high carbon dioxide conditions.Land and Food Systems, Faculty of
Graduate
9
Cakar, Zeynep Petek Çakar Zeynep Petek. "Metabolic engineering of yeast /". [S.l.] : [s.n.], 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13665.
Testo completo
10
Rodríguez, Porrata Boris alejandro. "Dehydration tolerance in yeast". Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/8678.
Testo completoAbstract (sommario):
La habilidad de las levaduras de superar la deshidratación y de reactivar su metabolismo después de la rehidratación tiene una importancia en la industria de los alimentos y en la biotecnología. Nosotros hemos dirigido nuestro trabajo a mejorar la viabilidad y vitalidad de las levaduras después de la rehidratación. Se realizaron estudios desde el punto de vista fisiológico de las levaduras durante la optimización de las condiciones de rehidratación y estudios moleculares como la determinación de los genes esenciales de respuesta a Secado y Rehidratación (SR) y la caracterización de la muerte celular a consecuencia del SR. Se sobre expresaron genes que codifican péptidos que permiten superar la viabilidad alcanzada por las levaduras bajo estas condiciones de estrés.Hipótesis de partida:
Algunos metabolitos y genes esenciales de respuesta a estrés por secado y rehidratación permiten a las levaduras tolerar la desecación
The ability of yeast to overcome dehydration and restart metabolism after rehydration has an importance in the food industry and biotechnology. We have directed our work to improve the viability and vitality of the yeast after rehydration. The studies were conducted in one hand from the physiological point of view to optimize rehydration conditions, and in the other hand from the molecular point of view. We identified the essential genes in response to drying and rehydration and its role in yeast cell death. Moreover we study the effect of over expressed some of this genes on yeast desiccation tolerance.
Hypothesis:
Some metabolites and essential genes in response to stress during drying and rehydration allow yeasts tolerate desiccation.
11
Conde, Pueyo Núria 1983. "Biological computation in yeast". Doctoral thesis, Universitat Pompeu Fabra, 2014. http://hdl.handle.net/10803/320193.
Testo completoAbstract (sommario):
Ongoing efforts within synthetic biology have been directed towards the building
of artificial computational devices using engineered biological units as basic
building blocks. Such efforts, are limited by the wiring problem: each
connection of the basic computational units (logic gates), must be implemented
by a different molecule.
We propose a non-standard way of implementing logic computations that reduces
wiring requirements thanks to a multicellular design with distribution of the
output among cells. Practical implementations are presented using a library of
engineered yeast cells, in which each genetic construct defines a logic
function. This shows the great potential for re-utilization of genetic elements
to build distinct cells. The cells are combined in multiple ways to easyly build
diferent complex synthetic circuits.
In the first manuscript, we proposed a multi-layer design. The engineered cells
can perform the IDENTITY, NOT, AND and N-IMPLIES logics and are able to
communicate with two different wiring molecules. As a proof of principle, we
have implemented many logic gates and more complex circuits such as a 1--bit
adder with carry.
In the second manuscript, a general architecture to engineer cellular consortia
that is independent of the circuit’s complexity is proposed. This design
involves cells, performing IDENTITY and NOT logics, organized in two layers. The
key aspect of the architecture is the spatial insulation. That design, permits
implementation of complex logical functions, such as 4to1—multiplexer only with
one wire.En el camp de la biologia sintètica els esforços s'han dirigit a construir dispositius computacionals artificials connectant les unitats lògiques bàsiques (portes lògiques). Aquests esforços, estan limitats per l'anomenat “wiring problem”: cada connexió entre les unitats lògiques s'ha d'implementar amb una molècula diferent. En aquesta tesi es mostra una manera no-estàndard d'implementar funcions lògiques que redueix el nombre de cables necessaris gràcies a un disseny multicel·lular amb una distribució de la sortida en diferents cèl·lules. Es presenta una implementació pràctica utilitzant una llibreria de cèl·lules de llevat enginyeritzades, on cada constructe genètic defineix una funció lògica. Això posa de manifest el gran potencial que suposa la re-utilització dels elements genètics per construir les diferents cèl·lules. Al mateix temps, les cèl·lules es poden combinar de múltiples maneres permetent la construcció fàcil de diferents circuits sintètics complexes. En el primer article, proposem un disseny en múltiples capes. Les cèl·lules modificades genèticament poden realitzar les lògiques: IDENTITY, NOT, AND i NIMPLIES i són capaces de comunicar-se utilitzant dues connexions diferents. Com a demostració experimental, s'han implementat varies portes lògiques i circuits més complexos tals com un sumador d'un bit. En el segon article, es proposa una arquitectura general, que defineix un consorci cèl·lular, capaç d'implementar qualsevol circuit independentment de la seva complexitat. Aquest disseny es basa en cèl·lules que realitzen les lògiques IDENTITY i NOT, organitzades en dues capes. L’aspecte clau d’aquesta arquitectura és l’aïllament espaial. Aquest disseny permet implementar funcions lògiques molt complexes tals com multiplexor—4a1 utilitzant una sola molècula cable.
12
Mirza, Memona. "Genetic recombination in yeast". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357567.
Testo completo
13
Dalgleish, Pamela Weir. "The yeast maltose transporter". Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/678.
Testo completo
14
Mata, Monteagudo Juan Ignacio. "Fission yeast cell polarity". Thesis, University College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265407.
Testo completo
15
White, C. I. "DNA repair in yeast". Thesis, Open University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333151.
Testo completo
16
Smit, Annel. "Maltotriose transport in yeast". Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/21760.
Testo completoAbstract (sommario):
Dissertation (PhD)--University of Stellenbosch, 2007.ENGLISH ABSTRACT: The conversion of sugar into ethanol and carbon dioxide is a process that has been intertwined with human culture and long as civilized man has existed. This fermentation process has been dominated by the micro-organism Saccharomyces cerevisiae and from providing ancient seafaring explorers of a non perishable beverage to equipping bakers with a raising agent to turn flour into bread; this organism with its fermentative potential, has formed an essential part of most societies. In more recent times, many industries still rely on this basic principle. The complexities and efficiencies of the conversion of sugar into its various fermentative byproducts have been studied and optimised extensively to meet the specific demands of industries. Depending on the raw material used as starting point, the major beneficiaries of the useful characteristics have been alcoholic beverage producers (wine, beer, and whiskey amongst others), bakers (bread leavening) and biofuel producers. One of the obstacles in fermentation optimisation is the sugar consumption preferences displayed by the organism used. S. cerevisiae can consume a wide variety of sugars. Depending on the complexities of its structures, it shows a preference for the simpler saccharides. The fermentation of certain more complex sugars is delayed and runs the risk of being left residually after fermentation. Many of the crops utilised in fermentation-based products contain large amounts of starch. During the starch degradation process many different forms of sugars are made available for fermentation. Improved fermentation of starch and its dextrin products would benefit the brewing, whiskey, and biofuel industries. Most strains of Saccharomyces ferment glucose and maltose, and partially ferment maltotriose, but are unable to utilise the larger dextrin products of starch. This utilisation pattern is partly attributed to the ability of yeast cells to transport the aforementioned mono-, di- and trisaccharides into the cytosol. The inefficiency of maltotriose transport has been identified as the main cause for residual maltotriose. The maltotriose transporting efficiency also varies between different Saccharomyces strains. By advancing the understanding of maltotriose transport in yeast, efforts can be made to minimise incomplete fermentation. This aim can be reached by investigating the existing transporters in the yeast cell membrane that show affinity for maltotriose. This study focuses on optimising maltotriose transport through the comparison of the alpha glucoside transporter obtained from different strains of Saccharomyces. Through specific genetic manipulations the areas important for maltotriose transport could be identified and characterised. This study offers prospects for the development of yeast strains with improved maltose and maltotriose uptake capabilities that, in turn, could increase the overall fermentation efficiencies in the beer, whiskey, and biofuel industries.
AFRIKAANSE OPSOMMING: Die transformasie van suiker na etanol en koolstof dioksied is so oud soos die beskawing self, en dit is van die vroegste tye af onlosmaaklik met die mens se kultuur verbind. Hierdie fermentasie-proses word gedomineer deur die Saccharomyces cerevisiae mikroorganisme. Hierdie organisme het antieke seevaarders voorsien van ‘n nie-bederfbare drankie en van ouds af aan bakkers ‘n rysmiddel verskaf waarmee meel in brood verander kon word. As gevolg van hierdie fermenteringspotensiaal het hierdie organisme ‘n onmisbare rol in meeste beskawings gespeel. Baie industrieë is steeds op hierdie basiese beginsel gebou. Die kompleksiteite en effektiwiteit van die transformasie van suiker na sy verskeie gefermeenteerde neweprodukte is breedvoerig bestudeer en geoptimiseer om aan die spesifieke behoeftes van verskeie industrieë te voeldoen. Afhangend van die grondstowwe wat as beginpunt gebruik is, is die primêre begunstigdes van die fermentasie proses die alkoholiese drankprodusente (onder andere die wyn-, bier- en whiskey produsente), bakkers en biobrandstofprodusente. Die suikerverbruik-voorkeur van die organisme wat die fermentering fasiliteer is een van die struikelblokke in die optimisering van die proses. S. cerevisiae kan ‘n wye spektrum van suikers verbruik maar dit toon ‘n voorkeur vir die eenvoudiger suikers. Die fermentasie van sekere van die meer komplekse suikers is vertraag en loop die risiko om agtergelaat te word na fermentasie. Vele van die gewasse wat in die gefermenteerde produkte gebruik word bevat groot hoeveelhede stysel. Vele soorte suikers word gedurende die afbreek van die stysel beskikbaar gestel vir fermentasie. Die brouers-, whiskey- en biobrandstof industrieë sal almal voordeel trek uit die verbeterde fermentasie van stysel en sy gepaardgaande dekstrin produkte. Meeste Saccharomyces gisrasse fermenteer glucose en maltose; maltotriose word gedeeltelik gefermenteer, maar die meer komplekse dekstrien produkte gevind in stysel word nie gefermenteer nie. Hierdie verbruikerspatroon kan gedeeltelik toegeskryf word aan die vermoë van gisselle om die bogenoemde mono-, di- and trisaccharides in die sitosol op te neem. Die oneffektiwiteit van maltotriose transport is identifiseer as die hoofoorsaak van post-fermentatiewe, oortollige maltotriose. Die effektiwiteit van maltotriose transport verskil ook tussen verskillende Saccharomyces rasse. Pogings om onvolledige fermentasie te veminder kan bevorder word deur die kennis rondom maltotriose transport in gis uit te bou. Hierdie oogmerk kan bereik word deur die bestaande transporters in die gissel se membraan wat ‘n affiniteit vir maltotriose toon te ondersoek. Hierdie studie fokus op die optimisering van maltotriose transport deur die vergelyking van die alpha glucoside transporter (AGT1) wat van verskillende Saccharomyces rasse afkomstig is. Die areas wat relevant is tot maltotriose transport kon deur spesifieke genetiese manipulasies identifiseer en gekarakteriseer word. Hierdie studie bevorder die vooruitsig op die ontwikkeling van gisrasse met verbeterde maltose en maltotriose transport vermoëns wat op sy beurt weer kan aanleiding gee tot die verbeterde fermentasie effektiwiteit in die bier, whiskey en biobrandstof industrieë.
17
Smith, C. A. M. "Sexual selection in yeast". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1336210/.
Testo completoAbstract (sommario):
Saccharomyces yeasts are unique as a model system in evolutionary biology. They offer all the traditional benefits of fast generation times and easy maintenance found in other microbes such as Escherichia coli. In addition, Saccharomyces are diploid eukaryotes capable of asexual and sexual reproduction. In this thesis I develop Saccharomyces as a model organism for the study of sexual selection. I show that its mating pheromone is costly to produce and maintain, and that this cost is greater for lower quality individuals. This suggests that the pheromone may have evolved as a sexual signal under the Handicap Principle. I show that size can offer direct benefits during mating and that these are in fact selected for. I show that preferential mating also takes place to help clear deleterious mutations from a population. I also investigate mating barriers in yeast to better understand how yeast mating may take place in nature.
18
Ooi, Siew Loon. "Yeast genetics of microarrays". Available to US Hopkins community, 2002. http://wwwlib.umi.com/dissertations/dlnow/3080738.
Testo completo
19
Priya, Vattem Padma. "Genomic distribution of histone H1 in budding yeast (Saccharomyces cerevisiae) : yeast chromosome III". Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/4324.
Testo completoAbstract (sommario):
Includes bibliographical references.The linker histone HI binds to the nucleosome and is essential for the organization of nucleosomes into the 30-nm filament of the chromatin. This compaction of DNA has a well-characterized effect on DNA function. In Saccharomyces cerevisiae, HHO 1 encodes a putative linker histone with very significant homology to histone HI. In vitro chromatin assembly experiments with recombinant Hho 1 p have shown that it is able to complex with the dinucleosomes in a similar manner to histone HI. It has also been reported that disruption of HHOl has little affect on RNA levels. A longstanding issue concerns the location of Hho 1 p in the chromatin and studies have shown using immunoprecipitation technique with anti-HA antibody, that Hho 1 p shows a preferential binding to rDNA sequences. In this project we have tried to confirm the above results in wild type cells, using immunopurifi ed anti rHho 1 p antibody.
20
Beh, Ai Lin Chemical Sciences & Engineering Faculty of Engineering UNSW. "Investigation of yeasts and yeast-like fungi associated with Australian wine grapes using cultural and molecular methods". Awarded by:University of New South Wales. Chemical Sciences & Engineering, 2007. http://handle.unsw.edu.au/1959.4/40683.
Testo completoAbstract (sommario):
This thesis presents a systematic investigation ofyeasts associated with wine grapes cultivated in several Australian vineyards during the 2001-2003 vintages. Using a combination of cultural and molecular methods, yeast populations of red (Cabernet sauvignon, Merlot, Tyrian) and white (Sauvignon blanc, Semilion) grape varieties were examined throughout grape cultivation. The yeast-like fungus, Aureobasidium pullulans, was the most prevalent species found on grapes. Various species of Cryptococcus, Rhodotorula and Sporobolomyces were frequently isolated throughout grape maturation. Ripe grapes showed an increased incidence of Hanseniaspora and Metschnikowia species for the 2001-2002 seasons, but not for the drought affected, 2002-2003 seasons. Atypical, hot and dry conditions may account for this difference in yeast flora and have limited comparisons of data to determine the influences of vineyard location, grape variety and pesticide applications on the yeast ecology. More systematic and controlled studies of these variables are required. Damaged grape berries harboured higher yeast populations and species diversity than intact healthy berries. PCR-DGGE analysis was less sensitive than plate culture for describing the diversity of yeast species on grapes; it detected prevalent species, but subdominant populations below 103 CFU/g were not detected. In some cases, PCR-DGGE revealed the presence ofyeasts (Candida galli, C. zemplinina) not isolated by culture. Fermentative wine species (Kluyveromyces, Torulaspora, Saccharomyces) were rarely isolated, and only detected by enrichment cultures. Significant morphological and genetic variability were detected among A. pullulans and other black yeasts isolates from grapes. Taxonomic characterization of 61 strains by ITS-RFLP and rDNA sequencing revealed that they belonged to several distinct species within the generic groupings ofAureobasidium, Hormonema and Kabatiella. Isolates were strong producers of extracellular enzymes and polysaccharides that could have oenological significance, and, using a plate assay, some were antagonistic towards Bacillus thuringiensis, several wine yeasts, and some spoilage and mycotoxigenic fungi found on grapes. Growth of Saccharomyces cerevisiae was not inhibited by these organisms in grape juice. A species-specific probe was developed for the identification of the wine spoilage yeast, Zygosaccharomyces bailii in a microtitre plate hybridization assay. The probe detected 102 cells/ml in wine, reliably differentiating Z. bailii from other Zygosaccharomyces and other wine-related yeasts.
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Beckhouse, Anthony Gordon Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "The transcriptional and physiological alterations in brewers yeast when shifted from anaerobic to aerobic growth conditions". Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/24201.
Testo completoAbstract (sommario):
Yeast are exposed to many physical and chemical stresses when used in large-scale industrial fermentations, particularly the initial stages in which yeast are shifted from anaerobic storage to aerated wort. This work investigated the transcriptional and physiological responses of yeast that had been shifted from anaerobic to aerobic growth conditions. Microarray technology was employed to determine the transcriptional changes that occurred in the first hour of a pilot-plant fermentation compared to the 23rd hour. It was found that over 100 genes were up-regulated initially including genes involved in the synthesis of the essential membrane sterol ergosterol and genes for the protection of cells against oxidative stress. It was also determined that cells which accumulate ergosterol precursors in the absence of ergosterol were more sensitive to exogenous oxidative stresses, indicating a role for ergosterol in oxidative stress tolerance. Aeration of anaerobically grown cells did not affect their growth kinetics or viability. However, anaerobically grown cells were hypersensitive to exogenous oxidative stress compared to their aerobic counterparts. Anaerobic cells that underwent a short period of aeration prior to treatment with hydrogen peroxide generated a tolerance to the oxidant, indicating that the period of aeration produced an adaptive-like response. Microarray analysis of the cells during the period of aeration showed that representative genes from the oxidative stress response family were up-regulated rapidly and it was determined that the response was controlled by the Yap1p and Skn7p transcription factors. Deletion of the transcription factor genes indicated that they were responsible for the creation of tolerance to oxidant. Target gene products of the two transcription factors (Gpx2p, Gsh1p and Trx2p) were shown to be induced during the shift to aeration; however, the glutathione redox balance did not seem to be affected as the cells were shifted from highly reduced to oxidising environments. Unexpectedly, it was discovered that genes involved in the synthesis of amino acids were up-regulated during anaerobic growth and stringently downregulated upon aeration of cells. The transcriptional activator of those genes (Gcn4p) was essential for growth in anaerobic media which included amino acid supplementation.
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Patch, Ann-Marie. "A comparative analysis of tandem repeats in the fission yeast and budding yeast genomes". Thesis, University of Exeter, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425493.
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Mains, Arlene Olive. "Evaluating the impact of yeast co-inoculation on individual yeast metabolism and wine composition". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96062.
Testo completoAbstract (sommario):
Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The use of non-Saccharomyces yeasts together with Saccharomyces cerevisiae in mixed starter cultures has become an accepted oenological tool to enhance the organoleptic properties of wine. Recent studies have indeed demonstrated the positive contribution that non- Saccharomyces yeasts may have on the bouquet of wine. These mixed starter cultures are characterized by high inoculation levels of individual strains into the must, and each strain in turn is characterized by its own specific metabolic activity. These factors lead to a multitude of interactions occurring between the individual populations within the must. The fundamental mechanisms which drive these interactions are still largely unknown, but several studies have been conducted in order to investigate the metabolic outcome of these interactions. In this study, we endeavour to further characterize the interactions which occur between four individual non-Saccharomyces yeast strains in mixed culture fermentation with S. cerevisiae. Metschnikowia pulcherrima IWBT Y1337, Lachancea thermotolerans IWBT Y1240, Issatchenkia orientalis Y1161 and Torulaspora delbrueckii CRBO LO544 were used in mixed culture fermentations with a commercial strain of S. cerevisiae at an inoculation ratio of 10:1 (non-Saccharomyces: S. cerevisiae). The biomass evolution and fermentation kinetics of both participating species were affected by the high cell density of the other, with neither population reaching the maximal density attained by the pure culture fermentation. The final wine composition of each individual mixed fermentation showed clear differences, from the pure cultured S. cerevisiae and from each other, based on the concentrations of the major volatile compounds found in the wine. Upon further characterization of these specific mixed culture fermentations, it was found that each individual combination of non-Saccharomyces and S. cerevisiae produced similar increases and decreases of certain major volatile compounds as demonstrated by previous authors, using the same combination of non-Saccharomyces species together with S. cerevisiae. From a winemaking perspective, the use of these non- Saccharomyces yeast strains in combination with S. cerevisiae could be a useful strategy to diversify the chemical composition of wine, by increasing the concentration of certain desirable volatile compounds and by modulating the concentration of undesirable metabolites. Furthermore, this research serves as a foundation for further elucidation of the interactions which drive these metabolic outcomes in response to the high cell density of two yeast populations in mixed culture fermentations.
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Catlin, Rachael. "Decolourization of yeast manufacturing wastewater /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe.pdf.
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Mixão, Verónica de Pinho 1991. "Hybridization in Candida yeast pathogens". Doctoral thesis, Universitat Pompeu Fabra, 2020. http://hdl.handle.net/10803/670103.
Testo completoAbstract (sommario):
Candida species are among the most important fungal pathogens. Although Candida albicans is the most common cause of Candida infections, many other Candida species have emerged as pathogens. How pathogenicity is evolutionary acquired is unknown, but previous studies point to a role of hybridization in its development. This thesis studied the genomic features of Candida pathogens, with a special focus on hybrids and their evolution. Specifically, it asked the questions of how spread are hybrids among Candida species, and what are the processes that drive the evolution of their genomes. To this end, genomes from 141 isolates belonging to 13 Candida species were analyzed and compared, to reconstruct their features and evolution. Overall, this thesis supports an important role of hybridization in the emergence of new yeast pathogens and provides novel insights on the evolutionary aftermath of hybridization.Candida spp. se encuentran entre los hongos patógenos más importantes. Candida albicans es la principal causante de infecciones por Candida, pero muchas otras especies del mismo género han emergido como patógenos. Los mecanismos evolutivos implicados en la adquisición de patogenicidad se desconocen, pero estudios precedentes apuntan a que la hibridación puede haber jugado un papel importante en este desarrollo. Esta tesis estudia las características genómicas de las especies patógenas del género Candida, centrándose en híbridos y su evolución. Específicamente, se analiza la presencia de híbridos entre las especies de Candida y se estudian los procesos que impulsan la evolución de sus genomas. Para ello, se analizaron y compararon los genomas de 141 cepas correspondientes a 13 especies con el propósito de reconstruir sus características genómicas y estudiar su evolución. En resumen, esta tesis respalda un papel importante de la hibridación en la aparición de nuevas levaduras patógenas y aporta nuevas ideas sobre las consecuencias evolutivas de dicha hibridación.
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Chen, Gang. "Assymmetric oxidations using "designer yeast"". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0015/NQ54589.pdf.
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Wilpe, Sandra van. "Protein import into yeast mitochondria". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/56852.
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Chen, G. "Assymmetric oxidations using "designer yeast"". Thesis, University of New Brunswick, 1999. http://hdl.handle.net/1882/852.
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Zinkevičienė, Auksė. "Yeast in atopic dermatitis etiology". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121107_091213-63157.
Testo completoAbstract (sommario):
Isolation and identification of all yeast species found on skin affected by atopic dermatitis, evaluation of their influence to the synthesis of IgE antibodies, and assessment of the possible cross-reactivity between different yeast species was performed. It was shown that in 36.9 % of the cases of atopic dermatitis, the affected skin was colonized with yeast belonging to three genera: Candida, Malassezia and Rhodotorula. Systematic and phylogenetic analysis of sequences from atypical Malassezia restricta strain M8 indicated that this isolate could be a member of a new yeast species. Three atypical Malassezia isolates M47, M54 and M235 were identified as non-lipid-dependent variants of Malassezia furfur. It was shown that in atopic dermatitis, cutaneous colonization with yeast is two-fold higher in adults than in children. The sera of atopic dermatitis patients have specific IgE antibodies to cross-reactive intracellular yeast antigens. Candida pelliculosa and house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae might share some allergenic epitopes. The results of this study suggest that attention should be given to a cutaneous colonization by saprophytic yeast since the immune response to the allergens could further exacerbate allergic inflammation due to cross-reactive epitopes.Išskirtos ir identifikuotos atopinio dermatito pažeistą odą kolonizuojančios mielių rūšys, įvertinta jų įtaka specifinių IgE antikūnų sintezei bei kryžminių reakcijų tarp skirtingų mielių rūšių galimybė. Nustatyta, kad 36,9 % atvejų atopinio dermatito pažeista oda yra kolonizuojama Candida, Malassezia ir Rhodotorula genties mielėmis. Išskirtas netipinėmis fiziologinėmis savybėmis pasižymintis Malassezia restricta kamienas M8 gali būti naujos rūšies atstovas. Išskirti netipinėmis fiziologinėmis savybėmis pasižymintys Malassezia genties kamienai M47, M54 ir M235 identifikuoti kaip nuo išorinio lipidų šaltinio nepriklausantys Malassezia furfur. Įrodyta, kad mielės suaugusių asmenų atopinio dermatito pažeistą odą kolonizuoja du kartus dažniau negu vaikų. Įrodyta, kad atopiniu dermatitu sergančių asmenų kraujo serume aptinkama prieš kryžmiškai reaguojančius mielių viduląstelinius antigenus nukreiptų specifinių IgE antikūnų. Taip pat nustatyta, kad Candida pelliculosa ir namų dulkių erkių Dermatophagoides pteronyssinus ir Dermatophagoides farinae alergenai gali turėti panašius epitopus. Darbo rezultatai patikimai rodo, kad atopinio dermatito pažeistą odą kolonizuojančios komensalinės mielės gali pasunkinti atopinio dermatito eigą dėl kryžmiškai reaguojančių epitopų tarp skirtingų biologinių rūšių antigenų.
30
Bird, Louise E. "Genetic engineering of brewing yeast". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259783.
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Goodwin, Adele. "Characterisation of yeast topoisomerase III". Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393573.
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Graves, Tara. "Yeast and corn mash fermentation". Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/2099.
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Nomura, Teruyuki. "Factors affecting yeast cell viability". Thesis, Heriot-Watt University, 1986. http://hdl.handle.net/10399/1061.
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Spink, Karen Gillian. "Telomeric proteins in fission yeast". Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312057.
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Ingley, Paul Michael. "Novel biosensor systems in yeast". Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426781.
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Mankouri, Hocine William. "DNA helicases and yeast ageing". Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367550.
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Docherty, R. C. "Transcription in isolated yeast mitochondria". Thesis, University of Essex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377926.
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Reynolds, Nicola C. "Genetic manipulation of yeast strains". Thesis, University of Greenwich, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276133.
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39
Jamas, Spiros. "Controlled biosynthesis of yeast glucans". Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/16492.
Testo completoAbstract (sommario):
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Applied Biological Sciences, 1986.Title as it appeared in M.I.T. Graduate List June 1987: Control of the structure-function properties of yeast glucans.
Bibliography: leaves 166-171.
by Spiros Jamas.
Sc.D.
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Stimpson, Helen Elizabeth Margaret. "Sorting into the yeast endosome". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615138.
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MacKenzie, Donald A. "Ribonucleic acid synthesis in yeast". Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/11088.
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42
Haw, Robin Andrew. "Functional analysis of yeast RAP1". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285773.
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43
Toenjes, Kurt Alan 1965. "Functional analysis of yeast fimbrin". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288802.
Testo completoAbstract (sommario):
The actin cytoskeleton has been implicated in the structural and mechanical properties of the cytoplasmic matrix. Actin and a number of actin associated proteins work in concert to carry out the various functions of the actin cytoskeleton. However, it is unclear how actin associated proteins function in conjunction with actin in vivo. I used Saccharomyces cerevisiae to investigate the actin cytoskeleton (1, 2, 3). Sac6 protein (Sac6p) is an actin bundling protein that consists of a head domain and two homologous actin binding domains (ABDs) (4). Despite their homology, evidence exists that there are functional differences between the ABDs. To explore these differences I asked if either ABD could function in place of the other by creating chimeric proteins with different combinations of the ABDs. When tested for function in vivo, these chimeric proteins are unable to complement the temperature and osmotic sensitivity of the sac6 null. This suggested that the ABDs of Sac6p are functionally distinct. To explore what functional differences exist between the ABDs of Sac6p, I made several truncations of Sac6p: a C-terminal deletion of Sac6p that retain the head and the first ABD (N410), and two different N-terminal deletions that contain only the second ABD (C386 & C397). Overexpression of N410 gave rise to a different organization of the actin cytoskeleton than did C386 or C397. This suggested that the ABDs/actin interactions are different. To determine whether the differences observed between the ABDs is the result of their interaction with actin, a method was developed to use allele specific suppression of the overexpression phenotype to define the region of interaction between the ABDs and actin. I tested full length Sac6p, N410, C386, and C397. The regions of actin implicated by suppression of the Sac6p overexpression and by allele specific suppression of sac6 mutants were similar. This similarity supports the validity of these two methods in mapping the regions of interaction between two proteins. Overexpression of N410 was suppressed by different actin mutations than overexpression of C386 or C397 suggesting that differences exist between the Sac6p actin binding domains in their interaction with actin.
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Giese, Wolfgang. "The choreography of yeast mating". Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17657.
Testo completoAbstract (sommario):
Die Forschung an der Hefe Saccharomyces cerevisiae – auch als Bäckerhefe bekannt – hat sich für die biologische Grundlagenforschung als unentbehrlich erwiesen und führte zu wichtigen Erkenntnissen in der Erforschung von Krankheiten wie Krebs. Am Beispiel der Paarung von Hefezellen werden in dieser Arbeit wesentliche Aspekte der eukaryotischen Zellbiologie untersucht. In der Haplophase des Lebenszyklus der Hefe, treten haploide Zellen als Paarungstyp MATa oder MATα auf. Diese Paarungstypen kommunizieren über Pheromone, die in ein extrazelluläres Medium abgesondert werden und von Zelloberflächenrezeptoren des komplementären Paarungstyps erkannt werden. Hefezellen wachsen in die Richtung eines möglichen Paarungspartners, da sie sich nicht aktiv bewegen können. Die Auswertung von empirischen Daten aus der Fluoreszenzmikroskopie und Rasterkraftmikroskopie (AFM) mit mathematischen Modellen ermöglichte die Rekonstruktion wesentlicher Prozesse der Hefepaarung: (i) Interzelluläre Kommunikation über die Sezernierung und Rezeption von Pheromonen, (ii) Aufbau der Zellpolarität als Reaktion auf die Pheromonantwort, (iii) Induktion und Mechanik der Zellformänderung. Folgende Modelle wurden dazu entwickelt: (i) Die interzelluläre Kommunikation wurde unter Verwendung von zellulären Automaten mit Hilfe von Reaktions-Diffusions (RD) Gleichungen modelliert. Das Modell zeigte, dass die gegenseitige Stimulierung und erhöhte Pheromonabsonderung zu einer verbesserten Abstimmung in der Paarung in der Zellpopulation führt. (ii) Ein Turing- und ein Phasenseparations- Mechanismus wurden als Modelle zum Aufbau der Zellpolarität verwendet. Volumen-Oberflächen gekoppelte RD Gleichungen wurden analytisch und numerisch mit der Finite-Elemente-Methode (FEM) untersucht. (iii) Die Zellwandveränderung wurde mit klassischer Kontinuumsmechanik und der FEM Methode modelliert. Dies ermöglichte eine Beschreibung der reversiblen elastischen und der irreversiblen plastischen Verformungen der Zellwand.Research on the yeast Saccharomyces cerevisiae – also known as baker’s yeast – has been essential not only for fostering basic biological knowledge but even more so for contributing towards understanding diseases such as cancer. In this thesis, general biological phenomena occurring in eukaryotic cells are investigated, exemplified by the mating process of yeast. In the haploid phase of their life cycle, yeast cells occur as mating type MATa or MATα, both of which communicate via pheromones that are secreted in an extracellular medium and can be sensed by cell-surface receptors of the complementary mating type. In order to mate, yeast cells grow towards a potential mating partner, since they are not able to actively move. Mathematical models on the basis of fluorescence and atomic force microscopy (AFM) data were developed. The key aspects of the yeast mating process that I examined were (i) intercellular communication of cells via pheromones, (ii) the initial symmetry break and implementation of cell polarity, and (iii) subsequent morphogenetic changes. The methods used and findings were as follows: (i) Pheromone secretion and sensing motifs were modelled using cellular automata models based on reaction-diffusion (RD) equations. My models show that mutual stimulation and increased pheromone secretion between cells improves mating efficiency in cell populations. (ii) To explain yeast mating decisions, two possible model types for cell polarity were tested: a Turing-type and a phase-separation mechanism. Bulk-surface RD equations were investigated analytically and numerically using the finite element method (FEM). Typical cell shapes were reconstructed in 2D and 3D. (iii) The cell wall was modelled using classical continuum mechanics that allows for reversible elastic and irreversible plastic cell wall deformation. Mathematical modelling demonstrated that all three processes investigated are precisely orchestrated and interlocked during yeast mating.
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McCormack, P. J. "The ecological significance of antibiotic production to yeasts and yeast-like organisms on the phylloplane". Thesis, University of Kent, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304835.
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Acun, Tolga. "Isolation And Characterization Of The K4 Type Yeast Killer Toxin". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1218684/index.pdf.
Testo completoAbstract (sommario):
Killer yeasts secrete polypeptide toxins which kill sensitive cells of their own
species and frequently those of other species and genera of yeasts. These protein compounds are designated as killer toxins. Also killer toxins of certain yeast strains have potential growth inhibitory activity on gram-positive pathogenic bacteria and plant pathogenic fungi. The yeasts are immune to their own killer protein. The killer phenomenon can be utilized for the protection of fermentation process against contaminating yeasts and for biological control of undesirable yeasts in the preservation of foods. The killer trait can also be used to produce large amount of foreign proteins in yeast. In the medical field , it is thought that their anti-microbial and anti-mycotic activity could be exploited in a therapeutic strategy.
Yeast killer toxins are classified into 11 types according to their killing
spectra and immunity-specificities such as K1, K2, etc. Altough there is
considerable amount of published information concerning the applications of yeast killer toxins , among the 11 types , only K1 , K2 and K6 have been characterized. In this study , it was aimed to purify and characterize the K4 type yeast killer toxin secreted by the Hansenula anomala NCYC 432. Gel permeation chromatography was performed to isolate the killer toxin by using a HPLC system. The toxin was
shown to be a glycoprotein having a molecular mass of between 49.08 kDa and 47.25 kDa and isoelectric point of between 3.77 and 3.41.
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Cao, Juxiang Locy Robert D. "Functional genomics of GABA metabolism in yeast thermotolerance". Auburn, Ala, 2008. http://repo.lib.auburn.edu/2007%20Fall%20Dissertations/Cao_Juxiang_41.pdf.
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Ha, Seon-Ah. "The role of the INP53 protein in membrane trafficking in yeast /". free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060102.
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Chu, Clement SM. "Towards the structure of yeast prions". Diss., Search in ProQuest Dissertations & Theses. UC Only, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3390039.
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Deumer, Claudia D. "RNA-binding proteins in yeast mitochondria". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2002. http://nbn-resolving.de/urn:nbn:de:swb:14-1035897639531-83407.
Testo completoAbstract (sommario):
This work focused on the further characterisation of Idhp and of the Krebs cycle enzymes citrate synthase 1 (Cit1p) and malate dehydrogenase 1 (Mdh1p) both of which have been identified as RNA-binding proteins without known RNA recognition motifs. Besides analysing their effects on mitochondrial translation and their organisation in protein complexes the work focused on the characterisation of the RNA-binding properties of recombinant Cit1p and Mdh1p: · Cit1p and Mdh1p play no essential role in mitochondrial protein synthesis. · Idhp is in a complex of molecular weight larger than the cytochrome c oxidase (250 kDa). · Cit1p and Mdh1p are in mitochondrial complexes smaller than 250 kDa. · 1000-fold molar excess of tRNA referring to COX2 leader RNA did not inhibit the RNA-binding of Cit1p and Mdh1p. · Cit1p and Mdh1p bind mitochondrial mRNAs (sense and antisense). The influence of cofactors and substrates on RNA-binding was analysed in order to reveal a possible link between the enzymatic function and the property of RNA-binding: · Acetyl-CoA and ATP inhibited the RNA-binding of Cit1p and Mdh1p at a concentration of 5 mM.