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Sample records for methylotropic yeast hanensula

  1. The Expression of Humanized Fab Fragment of the Anti-HBsAg Antibody in Methylotropic Yeast Pichia pastoris%人源性抗HBsAg抗体Fab段在酵母中的表达

    Institute of Scientific and Technical Information of China (English)

    邓宁; 粟宽源; 王珣章; 龙綮新; 杨林; 余宙耀

    2002-01-01

    通过分步整合的方式,将人源性抗乙肝表面抗原(HBsAg)抗体Fab的轻、重链基因分步整合到巴斯德毕赤(Pichia pastoris)酵母GS115菌株的染色体上,经甲醇诱导,成功地分泌表达出抗HBsAg抗体的Fab片段,表达量达50~80mg/L.ELISA结果显示重组酵母分泌表达出的Fab具有较强的结合HBsAg的能力.通过抗Fab的抗体柱亲和层析,纯化出了纯度较高的Fab产品.

  2. Expression of the mammalian renal peptide transporter PEPT2 in the yeast Pichia pastoris and applications of the yeast system for functional analysis.

    Science.gov (United States)

    Döring, F; Michel, T; Rösel, A; Nickolaus, M; Daniel, H

    1998-01-01

    It has recently been identified the PEPT2 cDNA encodes the high affinity proton-coupled peptide transporter in rabbit kidney cortex. PEPT2 represents a 729 amino acid protein with 12 putative transmembrane domains that mediates H+/H3O+ dependent electrogenic transmembrane transport of di- and tripeptides and of selected peptidomimetics. Here the functional expression of PEPT2 in the methylotropic yeast Pichia pastoris is described under the control of a methanol inducible promoter. Western blot analysis of Pichia cell membranes prepared from a recombinant clone identified a protein with an apparent molecular mass of about 85-87 kDa. Peptide uptake into cells expressing PEPT2 was up to 80 times higher than in control cells. Cells of recombinant clones showed a saturable peptide transport activity for the hydrolysis resistant dipeptide 3H-D-Phe-Ala with an app. K0.5 of 0.143 +/- 0.016 mM. Inhibition of 3H-D-Phe-Ala uptake by selected di- and tripeptides and beta-lactam antibiotics revealed the same substrate specificity as obtained in renal membrane vesicles or for PEPT2 when expressed in Xenopus laevis oocytes. A novel fluorescence based assay for assessing transport function based on a coumarin-labeled fluorescent peptide analogue has also been developed. Moreover, using a histidyl auxotrophe strain a PEPT2 expressing cell clone in which transport function can be monitored by a simple yeast growth test was established. In conclusion, this is one of only a few reports on successful functional expression of mammalian membrane transport proteins in yeast. The high expression level will provide a simple means for future studies either on the structure-affinity relationship for substrate interaction with PEPT2 or for selection of mutants generated by random mutagenesis.

  3. Yeast Lab

    OpenAIRE

    Lewis, Matt; Powell, Jim

    2016-01-01

    Yeast are grown in a small, capped ask, generating carbon dioxide which is trapped in an inverted jar full of colored water. The volume of carbon dioxide produced can either be measured directly or using time-lapse imagery on an iPad or similar. Students are then challenged to model the resulting data. From this exercise students gain greater understand- ing of ODE compartment models, parameter estimation, population dynamics and limiting factors.

  4. Yeast That Smell

    Directory of Open Access Journals (Sweden)

    Eugenia Y Xu

    2008-08-01

    Full Text Available The fundamental mechanism of olfactory receptor activation has been conserved from yeast to humans. Engineered yeast cells can smell some of the same odorants as humans can, which makes yeast an ideal model system for studying human olfaction. Furthermore, if engineered yeast cells are incorporated into sensory arrays, they can be used as biosensors or artificial noses.Keywords: Yeast, olfactory receptor, G protein-coupled receptor, biosensor, smellReceived: 31 July 2008 / Received in revised form: 6 August 2008, Accepted: 13 August 2008, Published online: 17 August 2008

  5. The yeast Golgi apparatus.

    Science.gov (United States)

    Suda, Yasuyuki; Nakano, Akihiko

    2012-04-01

    The Golgi apparatus is an organelle that has been extensively studied in the model eukaryote, yeast. Its morphology varies among yeast species; the Golgi exists as a system of dispersed cisternae in the case of the budding yeast Saccharomyces cerevisiae, whereas the Golgi cisternae in Pichia pastoris and Schizosaccharomyces pombe are organized into stacks. In spite of the different organization, the mechanism of trafficking through the Golgi apparatus is believed to be similar, involving cisternal maturation, in which the resident Golgi proteins are transported backwards while secretory cargo proteins can stay in the cisternae. Questions remain regarding the organization of the yeast Golgi, the regulatory mechanisms that underlie cisternal maturation of the Golgi and transport machinery of cargo proteins through this organelle. Studies using different yeast species have provided hints to these mechanisms.

  6. Yeast genome sequencing:

    DEFF Research Database (Denmark)

    Piskur, Jure; Langkjær, Rikke Breinhold

    2004-01-01

    For decades, unicellular yeasts have been general models to help understand the eukaryotic cell and also our own biology. Recently, over a dozen yeast genomes have been sequenced, providing the basis to resolve several complex biological questions. Analysis of the novel sequence data has shown...... of closely related species helps in gene annotation and to answer how many genes there really are within the genomes. Analysis of non-coding regions among closely related species has provided an example of how to determine novel gene regulatory sequences, which were previously difficult to analyse because...... they are short and degenerate and occupy different positions. Comparative genomics helps to understand the origin of yeasts and points out crucial molecular events in yeast evolutionary history, such as whole-genome duplication and horizontal gene transfer(s). In addition, the accumulating sequence data provide...

  7. Vaginal Yeast Infections

    Science.gov (United States)

    ... tight or made of materials like nylon that trap heat and moisture might make yeast infections more ... Nemours Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart.com

  8. Modeling brewers' yeast flocculation

    Science.gov (United States)

    van Hamersveld EH; van der Lans RG; Caulet; Luyben

    1998-02-01

    Flocculation of yeast cells occurs during the fermentation of beer. Partway through the fermentation the cells become flocculent and start to form flocs. If the environmental conditions, such as medium composition and fluid velocities in the tank, are optimal, the flocs will grow in size large enough to settle. After settling of the main part of the yeast the green beer is left, containing only a small amount of yeast necessary for rest conversions during the next process step, the lagering. The physical process of flocculation is a dynamic equilibrium of floc formation and floc breakup resulting in a bimodal size distribution containing single cells and flocs. The floc size distribution and the single cell amount were measured under the different conditions that occur during full scale fermentation. Influences on flocculation such as floc strength, specific power input, and total number of yeast cells in suspension were studied. A flocculation model was developed, and the measured data used for validation. Yeast floc formation can be described with the collision theory assuming a constant collision efficiency. The breakup of flocs appears to occur mainly via two mechanisms, the splitting of flocs and the erosion of yeast cells from the floc surface. The splitting rate determines the average floc size and the erosion rate determines the number of single cells. Regarding the size of the flocs with respect to the scale of turbulence, only the viscous subrange needs to be considered. With the model, the floc size distribution and the number of single cells can be predicted at a certain point during the fermentation. For this, the bond strength between the cells, the fractal dimension of the yeast, the specific power input in the tank and the number of yeast cells that are in suspension in the tank have to be known. Copyright 1998 John Wiley & Sons, Inc.

  9. Nitrile Metabolizing Yeasts

    Science.gov (United States)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

  10. Forces in yeast flocculation.

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N; Dufrêne, Yves F

    2015-02-07

    In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion ("flocculation") is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

  11. Mapping yeast transcriptional networks.

    Science.gov (United States)

    Hughes, Timothy R; de Boer, Carl G

    2013-09-01

    The term "transcriptional network" refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face. For most yeast TFs, data have been collected on their sequence preferences, in vivo promoter occupancy, and gene expression profiles in deletion mutants. These systematic studies have led to the identification of new regulators of numerous cellular functions and shed light on the overall organization of yeast gene regulation. However, many yeast TFs appear to be inactive under standard laboratory growth conditions, and many of the available data were collected using techniques that have since been improved. Perhaps as a consequence, comprehensive and accurate mapping among TF sequence preferences, promoter binding, and gene expression remains an open challenge. We propose that the time is ripe for renewed systematic efforts toward a complete mapping of yeast transcriptional regulatory mechanisms.

  12. [Fructose transporter in yeasts].

    Science.gov (United States)

    Lazar, Zbigniew; Dobrowolski, Adam; Robak, Małgorzata

    2014-01-01

    Study of hexoses transporter started with discovery of galactose permease in Saccharomyces cerevisiae. Glucose, fructose and mannose assimilation is assumed by numerous proteins encoded by different genes. To date over 20 hexoses transporters, belonging to Sugar Porter family and to Major Facilitator Superfamily, were known. Genome sequence analysis of Candida glabrata, Kluyveromyces lactis, Yarrowia lipolytica, S. cerevisaie and Debaryomyces hansenii reveled potential presence of 17-48 sugar porter proteins. Glucose transporters in S. cerevisiae have been already characterized. In this paper, hexoses transporters, responsible for assimilation of fructose by cells, are presented and compared. Fructose specific transporter are described for yeasts: Zygosaccharomyces rouxii, Zygosaccharomyces bailli, K. lactis, Saccharomyces pastorianus, S. cerevisiae winemaking strain and for fungus Botritys cinerea and human (Glut5p). Among six yeasts transporters, five are fructose specific, acting by facilitated diffusion or proton symport. Yeasts monosaccharides transporter studies allow understanding of sugars uptake and metabolism important aspects, even in higher eukaryotes cells.

  13. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric; Suominen, Pirkko

    2010-12-07

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

  14. Proteolytic activities in yeast.

    Science.gov (United States)

    Saheki, T; Holzer, H

    1975-03-28

    Studies on the mechanism and time course of the activation of proteinases A (EC 3.4.23.8), B (EC 3.4.22.9) and C (EC 3.4.12.--) in crude yeast extracts at pH 5.1 and 25 degrees C showed that the increase in proteinase B activity is paralleled with the disappearance of proteinase B inhibitor. Addition of purified proteinase A to fresh crude extracts accelerates the inactivation of the proteinase B inhibitor and the appearance of maximal activities of proteinases B and C. The decrease of proteinase B inhibitor activity and the increase of proteinase B activity are markedly retarded by the addition of pepstatin. Because 10-minus 7 M pepstatin completely inhibits proteinase A without affecting proteinase B activity, this is another indication for the role of proteinase A during the activation of proteinase B. Whereas extracts of yeast grown on minimal medium reached maximal activation of proteinases B and C after 20 h of incubation at pH 5.1 and 25 degrees C, extracts of yeast grown on complete medium had to be incubated for about 100 h. In the latter case, the addition of proteinas A results in maximal activation of proteinases B and C and disappearance of proteinase B inhibitor activity only after 10--20 h of incubation. With the optimal conditions, the maximal activities of proteinases A, B and C, as well as of the proteinase B inhibitor, were determined in crude extracts of yeast that had been grown batchwise for different lengths of time either on minimal or on complete medium. Upon incubation, all three proteinases were activated by several times their initial activity. This reflects the existence of proteolytically degradable inhibitors of the three proteinases and together with the above mentioned observations it demonstrates that the "activation" of yeast proteinases A, B and C upon incubation results from the proteolytic digestion of inhibitors rather than from activation of inactive zymogens by limited proteolysis.

  15. L-arabinose fermenting yeast

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

    2014-09-23

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

  16. L-arabinose fermenting yeast

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

    2013-02-12

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

  17. Flavour-active wine yeasts.

    Science.gov (United States)

    Cordente, Antonio G; Curtin, Christopher D; Varela, Cristian; Pretorius, Isak S

    2012-11-01

    The flavour of fermented beverages such as beer, cider, saké and wine owe much to the primary fermentation yeast used in their production, Saccharomyces cerevisiae. Where once the role of yeast in fermented beverage flavour was thought to be limited to a small number of volatile esters and higher alcohols, the discovery that wine yeast release highly potent sulfur compounds from non-volatile precursors found in grapes has driven researchers to look more closely at how choice of yeast can influence wine style. This review explores recent progress towards understanding the range of 'flavour phenotypes' that wine yeast exhibit, and how this knowledge has been used to develop novel flavour-active yeasts. In addition, emerging opportunities to augment these phenotypes by engineering yeast to produce so-called grape varietal compounds, such as monoterpenoids, will be discussed.

  18. Mapping Yeast Transcriptional Networks

    OpenAIRE

    Hughes, Timothy R; de Boer, Carl G.

    2013-01-01

    The term “transcriptional network” refers to the mechanism(s) that underlies coordinated expression of genes, typically involving transcription factors (TFs) binding to the promoters of multiple genes, and individual genes controlled by multiple TFs. A multitude of studies in the last two decades have aimed to map and characterize transcriptional networks in the yeast Saccharomyces cerevisiae. We review the methodologies and accomplishments of these studies, as well as challenges we now face....

  19. Glutathione Production in Yeast

    Science.gov (United States)

    Bachhawat, Anand K.; Ganguli, Dwaipayan; Kaur, Jaspreet; Kasturia, Neha; Thakur, Anil; Kaur, Hardeep; Kumar, Akhilesh; Yadav, Amit

    Glutathione, γ -glutamyl-cysteinyl-glycine, is the most abundant non-protein thiol found in almost all eukaryotic cells (and in some prokaryotes). The tripeptide, which is synthesized non-ribosomally by the consecutive action of two soluble enzymes, is needed for carrying out numerous functions in the cell, most important of which is the maintenance of the redox buffer. The cycle of glutathione biosynthesis and degradation forms part of the γ -glutamyl cycle in most organisms although the latter half of the pathway has not been demonstrated in yeasts. Our current understanding of how glutathione levels are controlled at different levels in the cell is described. Several different routes and processes have been attempted to increase commercial production of glutathione using both yeast and bacteria. In this article we discuss the history of glutathione production in yeast. The current bottlenecks for increased glutathione production are presented based on our current understanding of the regulation of glutathione homeostasis, and possible strategies for overcoming these limitations for further enhancing and improving glutathione production are discussed

  20. Genomics and the making of yeast biodiversity

    Science.gov (United States)

    Yeasts are unicellular fungi that do not form fruiting bodies. Although the yeast lifestyle has evolved multiple times, most known species belong to the subphylum Saccharomycotina (syn. Hemiascomycota, hereafter yeasts). This diverse group includes the premier eukaryotic model system, Saccharomyces ...

  1. Ethanol tolerance in yeasts.

    Science.gov (United States)

    Casey, G P; Ingledew, W M

    1986-01-01

    It is now certain that the inherent ethanol tolerance of the Saccharomyces strain used is not the prime factor regulating the level of ethanol that can be produced in a high sugar brewing, wine, sake, or distillery fermentation. In fact, in terms of the maximum concentration that these yeasts can produce under batch (16 to 17% [v/v]) or fed-batch conditions, there is clearly no difference in ethanol tolerance. This is not to say, however, that under defined conditions there is no difference in ethanol tolerance among different Saccharomyces yeasts. This property, although a genetic determinant, is clearly influenced by many factors (carbohydrate level, wort nutrition, temperature, osmotic pressure/water activity, and substrate concentration), and each yeast strain reacts to each factor differently. This will indeed lead to differences in measured tolerance. Thus, it is extremely important that each of these be taken into consideration when determining "tolerance" for a particular set of fermentation conditions. The manner in which each alcohol-related industry has evolved is now known to have played a major role in determining traditional thinking on ethanol tolerance in Saccharomyces yeasts. It is interesting to speculate on how different our thinking on ethanol tolerance would be today if sake fermentations had not evolved with successive mashing and simultaneous saccharification and fermentation of rice carbohydrate, if distillers' worts were clarified prior to fermentation but brewers' wort were not, and if grape skins with their associated unsaturated lipids had not been an integral part of red wine musts. The time is now ripe for ethanol-related industries to take advantage of these findings to improve the economies of production. In the authors' opinion, breweries could produce higher alcohol beers if oxygenation (leading to unsaturated lipids) and "usable" nitrogen source levels were increased in high gravity worts. White wine fermentations could also, if

  2. Inheritance of the yeast mitochondrial genome

    DEFF Research Database (Denmark)

    Piskur, Jure

    1994-01-01

    Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast......Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast...

  3. Yeast two-hybrid screen.

    Science.gov (United States)

    Makuch, Lauren

    2014-01-01

    Yeast two-hybrid is a method for screening large numbers of gene products (encoded by cDNA libraries) for their ability to interact with a protein of interest. This system can also be used for characterizing and manipulating candidate protein: protein interactions. Interactions between proteins are monitored by the growth of yeast plated on selective media.

  4. Evolutionary History of Ascomyceteous Yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Haridas, Sajeet; Riley, Robert; Salamov, Asaf; Goker, Markus; Klenk, Hans-Peter; Kurtzman, Cletus P.; Blackwell, Meredith; Grigoriev, Igor; Jeffries, Thomas W.

    2014-06-06

    Yeasts are important for many industrial and biotechnological processes and show remarkable diversity despite morphological similarities. We have sequenced the genomes of 16 ascomycete yeasts of taxonomic and industrial importance including members of Saccharomycotina and Taphrinomycotina. A comparison of these with several other previously published yeast genomes have added increased confidence to the phylogenetic positions of previously poorly placed species including Saitoella complicata, Babjeviella inositovora and Metschnikowia bicuspidata. Phylogenetic analysis also showed that yeasts with alternative nuclear codon usage where CUG encodes serine instead of leucine are monophyletic within the Saccharomycotina. Most of the yeasts have compact genomes with a large fraction of single exon genes with Lipomyces starkeyi and the previously published Pneumocystis jirovecii being notable exceptions. Intron analysis suggests that early diverging species have more introns. We also observed a large number of unclassified lineage specific non-simple repeats in these genomes.

  5. Production of Food Grade Yeasts

    Directory of Open Access Journals (Sweden)

    Argyro Bekatorou

    2006-01-01

    Full Text Available Yeasts have been known to humans for thousands of years as they have been used in traditional fermentation processes like wine, beer and bread making. Today, yeasts are also used as alternative sources of high nutritional value proteins, enzymes and vitamins, and have numerous applications in the health food industry as food additives, conditioners and flavouring agents, for the production of microbiology media and extracts, as well as livestock feeds. Modern scientific advances allow the isolation, construction and industrial production of new yeast strains to satisfy the specific demands of the food industry. Types of commercial food grade yeasts, industrial production processes and raw materials are highlighted. Aspects of yeast metabolism, with respect to carbohydrate utilization, nutritional aspects and recent research advances are also discussed.

  6. BIOSYNTHESIS OF YEAST CAROTENOIDS

    Science.gov (United States)

    Simpson, Kenneth L.; Nakayama, T. O. M.; Chichester, C. O.

    1964-01-01

    Simpson, Kenneth L. (University of California, Davis), T. O. M. Nakayama, and C. O. Chichester. Biosynthesis of yeast carotenoids. J. Bacteriol. 88:1688–1694. 1964.—The biosynthesis of carotenoids was followed in Rhodotorula glutinis and in a new strain, 62-506. The treatment of the growing cultures by methylheptenone, or ionone, vapors permitted observations of the intermediates in the biosynthetic pathway. On the basis of concentration changes and accumulation in blocked pathways, the sequence of carotenoid formation is postulated as phytoene, phytofluene, ζ-carotene, neurosporene, β-zeacarotene, γ-carotene, torulin, a C40 aldehyde, and torularhodin. Torulin and torularhodin were established as the main carotenoids of 62-506. PMID:14240958

  7. Cell Polarity in Yeast.

    Science.gov (United States)

    Chiou, Jian-Geng; Balasubramanian, Mohan K; Lew, Daniel J

    2017-08-07

    A conserved molecular machinery centered on the Cdc42 GTPase regulates cell polarity in diverse organisms. Here we review findings from budding and fission yeasts that reveal both a conserved core polarity circuit and several adaptations that each organism exploits to fulfill the needs of its lifestyle. The core circuit involves positive feedback by local activation of Cdc42 to generate a cluster of concentrated GTP-Cdc42 at the membrane. Speciesspecific pathways regulate the timing of polarization during the cell cycle, as well as the location and number of polarity sites. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 33 is October 6, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  8. Bioprotective Role of Yeasts

    Directory of Open Access Journals (Sweden)

    Serena Muccilli

    2015-10-01

    Full Text Available The yeasts constitute a large group of microorganisms characterized by the ability to grow and survive in different and stressful conditions and then to colonize a wide range of environmental and human ecosystems. The competitive traits against other microorganisms have attracted increasing attention from scientists, who proposed their successful application as bioprotective agents in the agricultural, food and medical sectors. These antagonistic activities rely on the competition for nutrients, production and tolerance of high concentrations of ethanol, as well as the synthesis of a large class of antimicrobial compounds, known as killer toxins, which showed clearly a large spectrum of activity against food spoilage microorganisms, but also against plant, animal and human pathogens. This review describes the antimicrobial mechanisms involved in the antagonistic activity, their applications in the processed and unprocessed food sectors, as well as the future perspectives in the development of new bio-drugs, which may overcome the limitations connected to conventional antimicrobial and drug resistance.

  9. Interaction Between Yeasts and Zinc

    Science.gov (United States)

    Nicola, Raffaele De; Walker, Graeme

    Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses

  10. Yeasts: from genetics to biotechnology.

    Science.gov (United States)

    Russo, S; Berkovitz Siman-Tov, R; Poli, G

    1995-01-01

    Yeasts have been known and used in food and alcoholic fermentations ever since the Neolithic Age. In more recent times, on the basis of their peculiar features and history, yeasts have become very important experimental models in both microbiological and genetic research, as well as the main characters in many fermentative production processes. In the last 40 years, advances in molecular biology and genetic engineering have made possible not only the genetic selection of organisms, but also the genetic modification of some of them, especially the simplest of them, such as bacteria and yeasts. These discoveries have led to the availability of new yeast strains fit to fulfill requests of industrial production and fermentation. Moreover, genetically modified and transformed yeasts have been constructed that are able to produce large amounts of biologically active proteins and enzymes. Thus, recombinant yeasts make it easier to produce drugs, biologically active products, diagnostics, and vaccines, by inexpensive and relatively simple techniques. Yeasts are going to become more and more important in the "biotechnological revolution" by virtue of both their features and their very long and safe use in human nutrition and industry.

  11. Marine Yeasts and Their Applications in Mariculture

    Institute of Scientific and Technical Information of China (English)

    CHI Zhenming; LIU Zhiqiang; GAO Lingmei; GONG Fang; MA Chunling; WANG Xianghong; LI Haifeng

    2006-01-01

    The terrestrial yeasts have been receiving great attention in science and industry for over one hundred years because they can produce many kinds of bioactive substances. However, little is known about the bioactive substances of marine yeasts. In recent years, it has been found that marine yeasts have wide applications in mariculture and other fields.Therefore, marine yeasts, the bioactive substances from them and the applications of marine yeasts themselves and the bioactive substances they produced are reviewed in this paper.

  12. Applications of yeast flocculation in biotechnological processes

    OpenAIRE

    Domingues, Lucília; Vicente, A.A.; Lima, Nelson; Teixeira, J. A.

    2000-01-01

    A review on the main aspects associated with yeast flocculation and its application in biotechnological processes is presented. This subject is addressed following three main aspects – the basics of yeast flocculation, the development of “new” flocculating yeast strains and bioreactor development. In what concerns the basics of yeast flocculation, the state of the art on the most relevant aspects of mechanism, physiology and genetics of yeast flocculation is reported. The const...

  13. Sexual differentiation in fission yeast

    DEFF Research Database (Denmark)

    Egel, R; Nielsen, O; Weilguny, D

    1990-01-01

    The regulation of sexual reproduction in yeast constitutes the highest level of differentiation observed in these unicellular organisms. The various ramifications of this system involve DNA rearrangement, transcriptional control, post-translational modification (such as protein phosphorylation...

  14. Biotechnical Microbiology, yeast and bacteria

    DEFF Research Database (Denmark)

    Villadsen, Ingrid Stampe

    1999-01-01

    This section contains the following single lecture notes: Eukaryotic Cell Biology. Kingdom Fungi. Cell Division. Meiosis and Recombination. Genetics of Yeast. Organisation of the Chromosome. Organization and genetics of the mitochondrial Geneme. Regulatio of Gene Expression. Intracellular...

  15. Biotechnical Microbiology, yeast and bacteria

    DEFF Research Database (Denmark)

    Villadsen, Ingrid Stampe

    1999-01-01

    This section contains the following single lecture notes: Eukaryotic Cell Biology. Kingdom Fungi. Cell Division. Meiosis and Recombination. Genetics of Yeast. Organisation of the Chromosome. Organization and genetics of the mitochondrial Geneme. Regulatio of Gene Expression. Intracellular Compart...

  16. Assimilation of nitrate by yeasts.

    Science.gov (United States)

    Siverio, José M

    2002-08-01

    Nitrate assimilation has received much attention in filamentous fungi and plants but not so much in yeasts. Recently the availability of classical genetic and molecular biology tools for the yeast Hansenula polymorpha has allowed the advance of the study of this metabolic pathway in yeasts. The genes YNT1, YNR1 and YNI1, encoding respectively nitrate transport, nitrate reductase and nitrite reductase, have been cloned, as well as two other genes encoding transcriptional regulatory factors. All these genes lie closely together in a cluster. Transcriptional regulation is the main regulatory mechanism that controls the levels of the enzymes involved in nitrate metabolism although other mechanisms may also be operative. The process involved in the sensing and signalling of the presence of nitrate in the medium is not well understood. In this article the current state of the studies of nitrate assimilation in yeasts as well as possible venues for future research are reviewed.

  17. Engineering antibodies by yeast display.

    Science.gov (United States)

    Boder, Eric T; Raeeszadeh-Sarmazdeh, Maryam; Price, J Vincent

    2012-10-15

    Since its first application to antibody engineering 15 years ago, yeast display technology has been developed into a highly potent tool for both affinity maturing lead molecules and isolating novel antibodies and antibody-like species. Robust approaches to the creation of diversity, construction of yeast libraries, and library screening or selection have been elaborated, improving the quality of engineered molecules and certainty of success in an antibody engineering campaign and positioning yeast display as one of the premier antibody engineering technologies currently in use. Here, we summarize the history of antibody engineering by yeast surface display, approaches used in its application, and a number of examples highlighting the utility of this method for antibody engineering.

  18. Sociobiology of the budding yeast

    Indian Academy of Sciences (India)

    Dominika M Wloch-Salamon

    2014-04-01

    Social theory has provided a useful framework for research with microorganisms. Here I describe the advantages and possible risks of using a well-known model organism, the unicellular yeast Saccharomyces cerevisiae, for sociobiological research. I discuss the problems connected with clear classification of yeast behaviour based on the fitness-based Hamilton paradigm. Relevant traits include different types of communities, production of flocculins, invertase and toxins, and the presence of apoptosis.

  19. Study of amyloids using yeast

    OpenAIRE

    Wickner, Reed B.; Kryndushkin, Dmitry; Shewmaker, Frank; McGlinchey, Ryan; Edskes, Herman K.

    2012-01-01

    Saccharomyces cerevisiae has been a useful model organism in such fields as the cell cycle, regulation of transcription, protein trafficking and cell biology, primarily because of its ease of genetic manipulation. This is no less so in the area of amyloid studies. The endogenous yeast amyloids described to date include prions, infectious proteins (Table 1), and some cell wall proteins (1). and amyloids of humans and a fungal prion have also been studied using the yeast system. Accordingly, th...

  20. Study of amyloids using yeast

    Science.gov (United States)

    Wickner, Reed B.; Kryndushkin, Dmitry; Shewmaker, Frank; McGlinchey, Ryan; Edskes, Herman K.

    2012-01-01

    Summary Saccharomyces cerevisiae has been a useful model organism in such fields as the cell cycle, regulation of transcription, protein trafficking and cell biology, primarily because of its ease of genetic manipulation. This is no less so in the area of amyloid studies. The endogenous yeast amyloids described to date include prions, infectious proteins (Table 1), and some cell wall proteins (1). and amyloids of humans and a fungal prion have also been studied using the yeast system. Accordingly, the emphasis of this chapter will be on genetic, biochemical, cell biological and physical methods particularly useful in the study of yeast prions and other amyloids studied in yeast. We limit our description of these methods to those aspects which have been most useful in studying yeast prions, citing more detailed expositions in the literature. Volumes on yeast genetics methods (2–4), and on amyloids and prions (5, 6) are useful, and Masison has edited a volume of Methods on “Identification, analysis and characterization of fungal prions” which covers some of this territory (7). We also outline some useful physical methods, pointing the reader to more extensive and authoratative descriptions. PMID:22528100

  1. Biotechnological Applications of Dimorphic Yeasts

    Science.gov (United States)

    Doiphode, N.; Joshi, C.; Ghormade, V.; Deshpande, M. V.

    The dimorphic yeasts have the equilibrium between spherical growth (budding) and polarized (hyphal or pseudohyphal tip elongation) which can be triggered by change in the environmental conditions. The reversible growth phenomenon has made dimorphic yeasts as an useful model to understand fungal evolution and fungal differentiation, in general. In nature dimorphism is clearly evident in plant and animal fungal pathogens, which survive and most importantly proliferate in the respective hosts. However, number of organisms with no known pathogenic behaviour also show such a transition, which can be exploited for the technological applications due to their different biochemical make up under different morphologies. For instance, chitin and chitosan production using dimorphic Saccharomyces, Mucor, Rhizopus and Benjaminiella, oil degradation and biotransformation with yeast-form of Yarrowia species, bioremediation of organic pollutants, exopolysac-charide production by yeast-phase of Aureobasidium pullulans, to name a few. Myrothecium verrucaria can be used for seed dressing in its yeast form and it produces a mycolytic enzyme complex in its hyphal-form for the biocontrol of fungal pathogens, while Beauveria bassiana and other entomopathogens kill the insect pest by producing yeast- like cells in the insect body. The form-specific expression of protease, chitinase, lipase, ornithine decarboxylase, glutamate dehydrogenases, etc. make Benjaminiella poitrasii, Basidiobolus sp., and Mucor rouxii strains important in bioremediation, nanobiotechnology, fungal evolution and other areas.

  2. Red Yeast Rice

    Science.gov (United States)

    Nguyen, Thu; Karl, Mitchell; Santini, Antonello

    2017-01-01

    Red yeast rice (RYR), produced by the fermentation of the Monascus purpureus mold, has been used for a long time in Asian cuisine and traditional medicine. It consists of multiple bioactive substances, including monacolins, which potentially can be used as a nutraceutical. Monacolin K, which is chemically identical to lovastatin, has been recognized as responsible for the cholesterol-reducing effect of this compound. While the European Food Safety Authority maintains that the use of monacolin K from RYR preparations of at least 10 mg can produce a normal blood cholesterol level, the United States Food and Drug Administration considers monacolin K, due to its similarity with lovastatin, an unapproved drug, and therefore marketing of products that label the monacolin content is prohibited. This mini-review summarizes the benefit of RYR in hyperlipidemia, maintains RYR use as a food, and addresses the importance of regulation regarding RYR and the need for clinical data and clear label information for consumers with reference to a toxin-free, non-augmented, standardized amount of monacolins. PMID:28257063

  3. Red Yeast Rice

    Directory of Open Access Journals (Sweden)

    Thu Nguyen

    2017-03-01

    Full Text Available Red yeast rice (RYR, produced by the fermentation of the Monascus purpureus mold, has been used for a long time in Asian cuisine and traditional medicine. It consists of multiple bioactive substances, including monacolins, which potentially can be used as a nutraceutical. Monacolin K, which is chemically identical to lovastatin, has been recognized as responsible for the cholesterolreducing effect of this compound. While the European Food Safety Authority maintains that the use of monacolin K from RYR preparations of at least 10 mg can produce a normal blood cholesterol level, the United States Food and Drug Administration considers monacolin K, due to its similarity with lovastatin, an unapproved drug, and therefore marketing of products that label the monacolin content is prohibited. This mini-review summarizes the benefit of RYR in hyperlipidemia, maintains RYR use as a food, and addresses the importance of regulation regarding RYR and the need for clinical data and clear label information for consumers with reference to a toxin-free, nonaugmented, standardized amount of monacolins.

  4. Yeast Genetics and Biotechnological Applications

    Science.gov (United States)

    Mishra, Saroj; Baranwal, Richa

    Yeast can be recognized as one of the very important groups of microorganisms on account of its extensive use in the fermentation industry and as a basic eukaryotic model cellular system. The yeast Saccharomyces cerevisiae has been extensively used to elucidate the genetics and regulation of several key functions in the cell such as cell mating, electron transport chain, protein trafficking, cell cycle events and others. Even before the genome sequence of the yeast was out, the structural organization and function of several of its genes was known. With the availability of the origin of replication from the 2 μm plasmid and the development of transformation system, it became the host of choice for expression of a number of important proteins. A large number of episomal and integrative shuttle vectors are available for expression of mammalian proteins. The latest developments in genomics and micro-array technology have allowed investigations of individual gene function by site-specific deletion method. The application of metabolic profiling has also assisted in understanding the cellular network operating in this yeast. This chapter is aimed at reviewing the use of this system as an experimental tool for conducting classical genetics. Various vector systems available, foreign genes expressed and the limitations as a host will be discussed. Finally, the use of various yeast enzymes in biotechnology sector will be reviewed.

  5. Emulsifying activity of hydrocarbonoclastic marine yeasts

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, R.

    Marine yeast growth on four petroleum hydrocarbons induced the production of extracellular emulsifying agents (biosurfactants). Out of the 17 marine yeast isolates tested, 7 isolates, i.e., Candida parapsilosis, C. cantarelli, C. membranae...

  6. Advances in yeast genome engineering.

    Science.gov (United States)

    David, Florian; Siewers, Verena

    2015-02-01

    Genome engineering based on homologous recombination has been applied to yeast for many years. However, the growing importance of yeast as a cell factory in metabolic engineering and chassis in synthetic biology demands methods for fast and efficient introduction of multiple targeted changes such as gene knockouts and introduction of multistep metabolic pathways. In this review, we summarize recent improvements of existing genome engineering methods, the development of novel techniques, for example for advanced genome redesign and evolution, and the importance of endonucleases as genome engineering tools.

  7. Yeast as factory and factotum.

    Science.gov (United States)

    Dixon, B

    2000-02-01

    After centuries of vigorous activity in making fine wines, beers and breads, Saccharomyces cerevisiae is now acquiring a rich new portfolio of skills, bestowed by genetic manipulation. As shown in a recent shop-window of research supported by the European Commission, yeasts will soon be benefiting industries as diverse as fish farming, pharmaceuticals and laundering.

  8. Black yeasts in cold habitats

    NARCIS (Netherlands)

    Selbmann, L.; de Hoog, G.S.; Zucconi, L.; Isola, D.; Onofri, S.; Buzzini, B.; Margesin, E.

    2014-01-01

    Black yeasts have already been known since the end of the nineteenth century, but for a number of reasons, only few workers were familiar with them. That was since recently, until the wealth of biodiversity, stunning ecologies and potential applications have become apparent. Some remote and extreme

  9. Nucleotide excision repair in yeast

    NARCIS (Netherlands)

    Eijk, Patrick van

    2012-01-01

    Nucleotide Excision Repair (NER) is a conserved DNA repair pathway capable of removing a broad spectrum of DNA damage. In human cells a defect in NER leads to the disorder Xeroderma pigmentosum (XP). The yeast Saccharomyces cerevisiae is an excellent model organism to study the mechanism of NER. The

  10. Surplus yeast tank failing catastrophically

    DEFF Research Database (Denmark)

    Hedlund, Frank Huess

    2016-01-01

    GOOD REASON FOR CAUTION I A large surplus yeast tank shot into the air leaving the floor plate and the contents behind. Although not designed for overpressure, the tank was kept at “very slight overpressure” to suppress nuisance foaming. The brewery was unaware of the hazards of compressed air. T....... The accident described in this article serves to illustrate that care should be taken if a tank originally designed for atmospheric pressure is modified to operate at slight overpressure.......GOOD REASON FOR CAUTION I A large surplus yeast tank shot into the air leaving the floor plate and the contents behind. Although not designed for overpressure, the tank was kept at “very slight overpressure” to suppress nuisance foaming. The brewery was unaware of the hazards of compressed air...

  11. Mycotoxins - prevention and decontamination by yeasts.

    Science.gov (United States)

    Pfliegler, Walter P; Pusztahelyi, Tünde; Pócsi, István

    2015-07-01

    The application of yeasts has great potential in reducing the economic damage caused by toxigenic fungi in the agriculture. Some yeasts may act as biocontrol agents inhibiting the growth of filamentous fungi. These species may also gain importance in the preservation of agricultural products and in the reduction of their mycotoxin contamination, yet the extent of mycotoxin production in the presence of biocontrol agents is relatively less understood. The application of yeasts in various technological processes may have a direct inhibitory effect on the toxin production of certain molds, which is independent of their growth suppressing effect. Furthermore, several yeast species are capable of accumulating mycotoxins from agricultural products, thereby effectively decontaminating them. Probiotic yeasts or products containing yeast cell wall are also applied to counteract mycotoxicosis in livestock. Several yeast strains are also able to degrade toxins to less-toxic or even non-toxic substances. This intensively researched field would greatly benefit from a deeper knowledge on the genetic and molecular basis of toxin degradation. Moreover, yeasts and their biotechnologically important enzymes may exhibit sensitivity to certain mycotoxins, thereby mounting a considerable problem for the biotechnological industry. It is noted that yeasts are generally regarded as safe; however, there are reports of toxin degrading species that may cause human fungal infections. The aspects of yeast-mycotoxin relations with a brief consideration of strain improvement strategies and genetic modification for improved detoxifying properties and/or mycotoxin resistance are reviewed here.

  12. Yeast: A new oil producer?

    Directory of Open Access Journals (Sweden)

    Beopoulos Athanasios

    2012-01-01

    Full Text Available The increasing demand of plant oils or animal fat for biodiesel and specific lipid derivatives for the oleochemical field (such as lubricants, adhesives or plastics have created price imbalance in both the alimentary and energy field. Moreover, the lack of non-edible oil feedstock has given rise to concerns on land-use practices and on oil production strategies. Recently, much attention has been paid to the exploitation of microbial oils. Most of them present lipid profiles similar in type and composition to plants and could therefore have many advantages as are no competitive with food, have short process cycles and their cultivation is independent of climate factors. Among microorganisms, yeasts seem to be very promising as they can be easily genetically enhanced, are suitable for large-scale fermentation and are devoid of endotoxins. This review will focus on the recent understanding of yeasts lipid metabolism, the succeeding genetic engineering of the lipid pathways and the recent developments on fermentation techniques that pointed out yeasts as promising alternative producers for oil or plastic.

  13. [Metabolomics analysis of taxadiene producing yeasts].

    Science.gov (United States)

    Yan, Huifang; Ding, Mingzhu; Yuan, Yingjin

    2014-02-01

    In order to study the inherent difference among terpenes producing yeasts from the point of metabolomics, we selected taxadiene producing yeasts as the model system. The changes of cellular metabolites during fermentation log phase of artificial functional yeasts were determined using metabolomics methods. The results represented that compared to W303-1A as a blank control, the metabolites in glycolysis, tricarboxylic acid cycle (TCA) cycle and several amino acids were influenced. And due to the changes of metabolites, the growth of cells was inhibited to a certain extent. Among the metabolites identified, citric acid content in taxadiene producing yeasts changed the most, the decreasing amplitude reached 90% or more. Therefore, citric acid can be a marker metabolite for the future study of artificial functional yeasts. The metabolomics analysis of taxadiene producing yeasts can provide more information in further studies on optimization of terpenes production in heterologous chassis.

  14. Yeasts Diversity in Fermented Foods and Beverages

    Science.gov (United States)

    Tamang, Jyoti Prakash; Fleet, Graham H.

    People across the world have learnt to culture and use the essential microorganisms for production of fermented foods and alcoholic beverages. A fermented food is produced either spontaneously or by adding mixed/pure starter culture(s). Yeasts are among the essential functional microorganisms encountered in many fermented foods, and are commercially used in production of baker's yeast, breads, wine, beer, cheese, etc. In Asia, moulds are predominant followed by amylolytic and alcohol-producing yeasts in the fermentation processes, whereas in Africa, Europe, Australia and America, fermented products are prepared exclusively using bacteria or bacteria-yeasts mixed cultures. This chapter would focus on the varieties of fermented foods and alcoholic beverages produced by yeasts, their microbiology and role in food fermentation, widely used commercial starters (pilot production, molecular aspects), production technology of some common commercial fermented foods and alcoholic beverages, toxicity and food safety using yeasts cultures and socio-economy

  15. Tracer studies of nitrogen assimilation in yeast.

    Science.gov (United States)

    ABRAMS, R; HAMMARSTEN, E

    1949-01-01

    By using N(15) as a tracer the assimilation of ammonia by the yeast, Torulopsis utilis, has been studied. It has been shown that: 1. There was no measurable incorporation of N in the protein or polynucleotide purine of carbon-starved yeast. 2. When ammonia is added to nitrogen-starved yeast there is a long lag period before division begins during which the yeast rapidly synthesizes protein, this process being accompanied by a turnover of polynucleotide purine. There was no significant dilution of the N(15)H(4) (+) of the medium by ordinary NH(4) (+). 3. When yeast containing N(15) is allowed to divide and grow in ordinary ammonia, the total amount of N(15) in the yeast remains constant. The dicarboxylic amino acids are most diluted, while arginine and nucleic acid guanine are not diluted at all.

  16. Beer brewing using a fusant between a sake yeast and a brewer's yeast.

    Science.gov (United States)

    Mukai, N; Nishimori, C; Fujishige, I W; Mizuno, A; Takahashi, T; Sato, K

    2001-01-01

    Beer brewing using a fusant between a sake yeast (a lysine auxotrophic mutant of sake yeast K-14) and a brewer's yeast (a respiratory-deficient mutant of the top fermentation yeast NCYC1333) was performed to take advantage of the beneficial characteristics of sake yeasts, i.e., the high productivity of esters, high tolerance to ethanol, and high osmotolerance. The fusant (F-32) obtained was different from the parental yeasts regarding, for example, the assimilation of carbon sources and tolerance to ethanol. A brewing trial with the fusant was carried out using a 100-l pilot-scale plant. The fusant fermented wort more rapidly than the parental brewer's yeast. However, the sedimentation capacity of the fusant was relatively low. The beer brewed using the fusant contained more ethanol and esters compared to that brewed using the parental brewer's yeast. The fusant also obtained osmotolerance in the fermentation of maltose and fermented high-gravity wort well.

  17. Assembly of eukaryotic algal chromosomes in yeast

    OpenAIRE

    Karas, Bogumil J.; Molparia, Bhuvan; Jablanovic, Jelena; Hermann, Wolfgang J; Lin, Ying-Chi; Dupont, Christopher L.; Tagwerker, Christian; Yonemoto, Isaac T.; Noskov, Vladimir N.; Chuang, Ray-Yuan; Allen, Andrew E; Glass, John I.; Hutchison, Clyde A; Smith, Hamilton O; Venter, J Craig

    2013-01-01

    Background Synthetic genomic approaches offer unique opportunities to use powerful yeast and Escherichia coli genetic systems to assemble and modify chromosome-sized molecules before returning the modified DNA to the target host. For example, the entire 1 Mb Mycoplasma mycoides chromosome can be stably maintained and manipulated in yeast before being transplanted back into recipient cells. We have previously demonstrated that cloning in yeast of large (> ~ 150 kb), high G + C (55%) prokaryoti...

  18. 21 CFR 73.355 - Phaffia yeast.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Phaffia yeast. 73.355 Section 73.355 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.355 Phaffia yeast. (a) Identity. (1) The color additive phaffia yeast consists of the killed, dried cells...

  19. Adhesive interactions between medically important yeasts and bacteria

    NARCIS (Netherlands)

    Millsap, KW; van der Mei, HC; Busscher, HJ; Bos, R.R.M.

    Yeasts are being increasingly identified as important organisms in human infections. Adhesive interactions between yeasts and bacteria may contribute to yeast retention al body sites. Methods for studying adhesive interactions between bacterial strains are well known, and range from simple

  20. Yeast cell factories on the horizon

    DEFF Research Database (Denmark)

    Nielsen, Jens

    2015-01-01

    For thousands of years, yeast has been used for making beer, bread, and wine. In modern times, it has become a commercial workhorse for producing fuels, chemicals, and pharmaceuticals such as insulin, human serum albumin, and vaccines against hepatitis virus and human papillomavirus. Yeast has al...

  1. Yeasts are essential for cocoa bean fermentation.

    Science.gov (United States)

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2014-03-17

    Cocoa beans (Theobroma cacao) are the major raw material for chocolate production and fermentation of the beans is essential for the development of chocolate flavor precursors. In this study, a novel approach was used to determine the role of yeasts in cocoa fermentation and their contribution to chocolate quality. Cocoa bean fermentations were conducted with the addition of 200ppm Natamycin to inhibit the growth of yeasts, and the resultant microbial ecology and metabolism, bean chemistry and chocolate quality were compared with those of normal (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii and Kluyveromyces marxianus, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in the control fermentation. In fermentations with the presence of Natamycin, the same bacterial species grew but yeast growth was inhibited. Physical and chemical analyses showed that beans fermented without yeasts had increased shell content, lower production of ethanol, higher alcohols and esters throughout fermentation and lesser presence of pyrazines in the roasted product. Quality tests revealed that beans fermented without yeasts were purplish-violet in color and not fully brown, and chocolate prepared from these beans tasted more acid and lacked characteristic chocolate flavor. Beans fermented with yeast growth were fully brown in color and gave chocolate with typical characters which were clearly preferred by sensory panels. Our findings demonstrate that yeast growth and activity were essential for cocoa bean fermentation and the development of chocolate characteristics.

  2. Yeasts in sustainable bioethanol production: A review

    Directory of Open Access Journals (Sweden)

    Siti Hajar Mohd Azhar

    2017-07-01

    Full Text Available Bioethanol has been identified as the mostly used biofuel worldwide since it significantly contributes to the reduction of crude oil consumption and environmental pollution. It can be produced from various types of feedstocks such as sucrose, starch, lignocellulosic and algal biomass through fermentation process by microorganisms. Compared to other types of microoganisms, yeasts especially Saccharomyces cerevisiae is the common microbes employed in ethanol production due to its high ethanol productivity, high ethanol tolerance and ability of fermenting wide range of sugars. However, there are some challenges in yeast fermentation which inhibit ethanol production such as high temperature, high ethanol concentration and the ability to ferment pentose sugars. Various types of yeast strains have been used in fermentation for ethanol production including hybrid, recombinant and wild-type yeasts. Yeasts can directly ferment simple sugars into ethanol while other type of feedstocks must be converted to fermentable sugars before it can be fermented to ethanol. The common processes involves in ethanol production are pretreatment, hydrolysis and fermentation. Production of bioethanol during fermentation depends on several factors such as temperature, sugar concentration, pH, fermentation time, agitation rate, and inoculum size. The efficiency and productivity of ethanol can be enhanced by immobilizing the yeast cells. This review highlights the different types of yeast strains, fermentation process, factors affecting bioethanol production and immobilization of yeasts for better bioethanol production.

  3. The wine and beer yeast Dekkera bruxellensis

    Science.gov (United States)

    Schifferdecker, Anna Judith; Dashko, Sofia; Ishchuk, Olena P; Piškur, Jure

    2014-01-01

    Recently, the non-conventional yeast Dekkera bruxellensis has been gaining more and more attention in the food industry and academic research. This yeast species is a distant relative of Saccharomyces cerevisiae and is especially known for two important characteristics: on the one hand, it is considered to be one of the main spoilage organisms in the wine and bioethanol industry; on the other hand, it is 'indispensable' as a contributor to the flavour profile of Belgium lambic and gueuze beers. Additionally, it adds to the characteristic aromatic properties of some red wines. Recently this yeast has also become a model for the study of yeast evolution. In this review we focus on the recently developed molecular and genetic tools, such as complete genome sequencing and transformation, to study and manipulate this yeast. We also focus on the areas that are particularly well explored in this yeast, such as the synthesis of off-flavours, yeast detection methods, carbon metabolism and evolutionary history. © 2014 The Authors. Yeast published by John Wiley & Sons, Ltd. PMID:24932634

  4. The wine and beer yeast Dekkera bruxellensis.

    Science.gov (United States)

    Schifferdecker, Anna Judith; Dashko, Sofia; Ishchuk, Olena P; Piškur, Jure

    2014-09-01

    Recently, the non-conventional yeast Dekkera bruxellensis has been gaining more and more attention in the food industry and academic research. This yeast species is a distant relative of Saccharomyces cerevisiae and is especially known for two important characteristics: on the one hand, it is considered to be one of the main spoilage organisms in the wine and bioethanol industry; on the other hand, it is 'indispensable' as a contributor to the flavour profile of Belgium lambic and gueuze beers. Additionally, it adds to the characteristic aromatic properties of some red wines. Recently this yeast has also become a model for the study of yeast evolution. In this review we focus on the recently developed molecular and genetic tools, such as complete genome sequencing and transformation, to study and manipulate this yeast. We also focus on the areas that are particularly well explored in this yeast, such as the synthesis of off-flavours, yeast detection methods, carbon metabolism and evolutionary history. © 2014 The Authors. Yeast published by John Wiley & Sons, Ltd.

  5. Growth requirements of san francisco sour dough yeasts and bakers' yeast.

    Science.gov (United States)

    Henry, N

    1976-03-01

    The growth requirements of several yeasts isolated from San Francisco sour dough mother sponges were compared with those of bakers' yeast. The sour dough yeasts studied were one strain of Saccharomyces uvarum, one strain of S. inusitatus, and four strains of S. exiguus. S. inusitatus was the only yeast found to have an amino acid requirement, namely, methionine. All of the yeasts had an absolute requirement for pantothenic acid and a partial requirement for biotin. Inositol was stimulatory to all except bakers' yeast. All strains of S. exiguus required niacin and thiamine. Interestingly, S. inusitatus, the only yeast that required methionine, also needed folic acid. For optimal growth of S. exiguus in a molasses medium, supplementation with thiamine was required.

  6. Genetic constitution of industrial yeast.

    Science.gov (United States)

    Benítez, T; Martínez, P; Codón, A C

    1996-09-01

    Saccharomyces cerevisiae industrial yeast strains are highly heterogeneous. These industrial strains, including bakers', wine, brewing and distillers', have been compared with respect to their DNA content, number and size of chromosomes, homologies between their genes and those of laboratory strains, and restriction fragment lengths of their mitDNA. A high variability, and the presence of multigenic families, were observed in some industrial yeast groups. The occurrence or the lack of chromosomal polymorphism, as well as the presence of multiple copies of some genes, could be related to a selective process occurring under specific industrial conditions. This polymorphism is generated by reorganization events, that take place mainly during meiosis and are mediated by repetitive Y' and Ty elements. These elements give rise to ectopic and asymmetric recombination and to gene conversion. The polymorphism displayed by the mitDNA could also result from specific industrial conditions. However, in enological strains the selective process is masked by the mutagenic effect that ethanol exerts on this DNA.

  7. Antifungal resistance in yeast vaginitis.

    Science.gov (United States)

    Dun, E.

    1999-01-01

    The increased number of vaginal yeast infections in the past few years has been a disturbing trend, and the scientific community has been searching for its etiology. Several theories have been put forth to explain the apparent increase. First, the recent widespread availability of low-dosage, azole-based over-the-counter antifungal medications for vaginal yeast infections encourages women to self-diagnose and treat, and women may be misdiagnosing themselves. Their vaginitis may be caused by bacteria, parasites or may be a symptom of another underlying health condition. As a result, they may be unnecessarily and chronically expose themselves to antifungal medications and encourage fungal resistance. Second, medical technology has increased the life span of seriously immune compromised individuals, yet these individuals are frequently plagued by opportunistic fungal infections. Long-term and intense azole-based antifungal treatment has been linked to an increase in resistant Candida and non-Candida species. Thus, the future of limiting antifungal resistance lies in identifying the factors promoting resistance and implementing policies to prevent it. PMID:10907778

  8. Harnessing yeast organelles for metabolic engineering.

    Science.gov (United States)

    Hammer, Sarah K; Avalos, José L

    2017-08-01

    Each subcellular compartment in yeast offers a unique physiochemical environment and metabolite, enzyme, and cofactor composition. While yeast metabolic engineering has focused on assembling pathways in the cell cytosol, there is growing interest in embracing subcellular compartmentalization. Beyond harnessing distinct organelle properties, physical separation of organelles from the cytosol has the potential to eliminate metabolic crosstalk and enhance compartmentalized pathway efficiency. In this Perspective we review the state of the art in yeast subcellular engineering, highlighting the benefits of targeting biosynthetic pathways to subcellular compartments, including mitochondria, peroxisomes, the ER and/or Golgi, vacuoles, and the cell wall, in different yeast species. We compare the performances of strains developed with subcellular engineering to those of native producers or yeast strains previously engineered with cytosolic pathways. We also identify important challenges that lie ahead, which need to be addressed for organelle engineering to become as mainstream as cytosolic engineering in academia and industry.

  9. Comet assay on tetraploid yeast cells

    DEFF Research Database (Denmark)

    Rank, Jette; Syberg, Kristian; Jensen, Klara

    2009-01-01

    Tetraploid yeast cells (Saccharomyces cerevisiae) were used in the comet assay with the intention of developing a new, fast and easy assay for detecting environmental genotoxic agents without using higher organisms. Two DNA-damaging chemicals, H2O2 and acrylamide, together with wastewater from...... three municipal treatment plants were tested for their effect on the yeast-cell DNA. The main problem with using yeast in the comet assay is the necessity to degrade the cell wall. This was achieved by using Zymolase 100 T twice during the procedure, since Zymolase 20 T did not open the cell wall....... Analytical problems that arose due to the small amount of DNA in the yeast nuclei in haploid and diploid cells, which contain 13 Mbp and 26 Mbp DNA per cell, respectively, were solved by using tetraploid yeast cells (52 Mbp) instead. DNA damage was shown after exposure to H2O2 and acrylamide. The lowest dose...

  10. Yeasts associated with Cheddar and Gouda making.

    Science.gov (United States)

    Viljoen, B C; Greyling, T

    1995-11-01

    Sources of yeast contamination which may lead to contamination of the curd during Cheddar and Gouda cheese making, were examined in a single cheese factory. A total of 187 representative yeast isolates present in the factory environment, on working surfaces, the brine and on workers' hands and aprons were identified according to conventional methods and cellular long-chain fatty acid analyses. Product line samples were taken at critical control points in the manufacturing process and analysed after incubation at 25 degrees C for 96 h. The most prevalent isolates belonged to the genera Debaryomyces and Candida. Other genera encountered were Cryptococcus, Rhodotorula, Yarrowia, Pichia, Trichosporon, Torulaspora, Issatchenkia, Saccharomyces and Zygosaccharomyces. Characterization of the predominant yeast isolates indicated that the cheese brine was responsible for the largest variety and number of yeast isolates yielding a total of 64 yeast strains belonging to nine different genera.

  11. Yeast community survey in the Tagus estuary.

    Science.gov (United States)

    de Almeida, João M G C F

    2005-07-01

    The yeast community in the waters of the Tagus estuary, Portugal, was followed for over a year in order to assess its dynamics. Yeast occurrence and incidence were measured and this information was related to relevant environmental data. Yeast occurrence did not seem to depend upon tides, but river discharge had a dramatic impact both on the density and diversity of the community. The occurrence of some yeasts was partially correlated with faecal pollution indicators. Yeast isolates were characterized by microsatellite primed PCR (MSP-PCR) fingerprinting and rRNA gene sequencing. The principal species found were Candida catenulata, C. intermedia, C. parapsilosis, Clavispora lusitaniae, Debaryomyces hansenii, Pichia guilliermondii, Rhodotorula mucilaginosa and Rhodosporidium diobovatum. The incidence of these species was evaluated against the environmental context of the samples and the current knowledge about the substrates from which they are usually isolated.

  12. Accelerating Yeast Prion Biology using Droplet Microfluidics

    Science.gov (United States)

    Ung, Lloyd; Rotem, Assaf; Jarosz, Daniel; Datta, Manoshi; Lindquist, Susan; Weitz, David

    2012-02-01

    Prions are infectious proteins in a misfolded form, that can induce normal proteins to take the misfolded state. Yeast prions are relevant, as a model of human prion diseases, and interesting from an evolutionary standpoint. Prions may also be a form of epigenetic inheritance, which allow yeast to adapt to stressful conditions at rates exceeding those of random mutations and propagate that adaptation to their offspring. Encapsulation of yeast in droplet microfluidic devices enables high-throughput measurements with single cell resolution, which would not be feasible using bulk methods. Millions of populations of yeast can be screened to obtain reliable measurements of prion induction and loss rates. The population dynamics of clonal yeast, when a fraction of the cells are prion expressing, can be elucidated. Furthermore, the mechanism by which certain strains of bacteria induce yeast to express prions in the wild can be deduced. Integrating the disparate fields of prion biology and droplet microfluidics reveals a more complete picture of how prions may be more than just diseases and play a functional role in yeast.

  13. Corning and Kroger turn whey to yeast

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-16

    It is reported that Corning and Kroger intend to build a 35,000 sq. ft. plant in Winchester, Ky., that will turn whey into bakers' yeast. The plant will convert whey from Kroger's dairies into bakers' yeast, supplying about 60% of the yeast needed for nine Kroger bakeries. It will also produce syrups and whey protein concentrate for use in other food processing activities. In addition to making useful products, the project will convert the whey to glucose and galactose. The protein component of the whey will be concentrated and used in various foods and feeds.

  14. Pseudoporphyria associated with consumption of brewers' yeast.

    Science.gov (United States)

    Lim, C K; Rideout, J M; Peters, T J

    1984-06-01

    A case of pseudoporphyria associated with excessive consumption of brewers ' yeast was studied. Detailed analysis of the yeast tablets by high performance liquid chromatography showed the presence of dicarboxylic deuteroporphyrin , mesoporphyrin, and protoporphyrin; coproporphyrin I and III isomers; and uroporphyrin I and III isomers. The faecal porphyrin concentration of the patient taking yeast tablets was significantly increased, resembling the excretion pattern in variegate porphyria. Any patient showing an unusual porphyrin excretion pattern on high performance liquid chromatography should be investigated for a possible dietary cause.

  15. 21 CFR 172.325 - Bakers yeast protein.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Bakers yeast protein. 172.325 Section 172.325 Food... Special Dietary and Nutritional Additives § 172.325 Bakers yeast protein. Bakers yeast protein may be safely used in food in accordance with the following conditions: (a) Bakers yeast protein is the...

  16. YeastWeb: a workset-centric web resource for gene family analysis in yeast

    Directory of Open Access Journals (Sweden)

    Bao Haihua

    2010-07-01

    Full Text Available Abstract Background Currently, a number of yeast genomes with different physiological features have been sequenced and annotated, which provides invaluable information to investigate yeast genetics, evolutionary mechanism, structure and function of gene families. Description YeastWeb is a novel database created to provide access to gene families derived from the available yeast genomes by assigning the genes into putative families. It has many useful features that complement existing databases, such as SGD, CYGD and Génolevures: 1 Detailed computational annotation was conducted with each entry with InterProScan, EMBOSS and functional/pathway databases, such as GO, COG and KEGG; 2 A well established user-friendly environment was created to allow users to retrieve the annotated genes and gene families using functional classification browser, keyword search or similarity-based search; 3 Workset offers users many powerful functions to manage the retrieved data efficiently, associate the individual items easily and save the intermediate results conveniently; 4 A series of comparative genomics and molecular evolution analysis tools are neatly implemented to allow users to view multiple sequence alignments and phylogenetic tree of gene families. At present, YeastWeb holds the gene families clustered from various MCL inflation values from a total of 13 available yeast genomes. Conclusions Given the great interest in yeast research, YeastWeb has the potential to become a useful resource for the scientific community of yeast biologists and related researchers investigating the evolutionary relationship of yeast gene families. YeastWeb is available at http://centre.bioinformatics.zj.cn/Yeast/.

  17. Structure and function of yeast alcohol dehydrogenase

    Directory of Open Access Journals (Sweden)

    VLADIMIR LESKOVAC

    2000-04-01

    Full Text Available 1. Introduction 2. Isoenzymes of YADH 3. Substrate specificity 4. Kinetic mechanism 5. Primary structure 6. The active site 7. Mutations in the yeast enzyme 8. Chemical mechanism 9. Binding of coenzymes 10. Hydride transfer

  18. Monitoring Air Quality with Leaf Yeasts.

    Science.gov (United States)

    Richardson, D. H. S.; And Others

    1985-01-01

    Proposes that leaf yeast serve as quick, inexpensive, and effective techniques for monitoring air quality. Outlines procedures and provides suggestions for data analysis. Includes results from sample school groups who employed this technique. (ML)

  19. Optimization of yeast (Saccharomyces cerevisiae) RNA isolation ...

    African Journals Online (AJOL)

    Yomi

    2012-01-16

    Jan 16, 2012 ... the center of research ranging from studies of human disease genes to experimental evolution and systems biology (Landry et al., 2006). ... cells and Lyticase as the most efficient in producing high quality yeast total RNA.

  20. yeast transformation of Mucor circinelloides Tieghe

    African Journals Online (AJOL)

    GRACE

    2006-05-02

    May 2, 2006 ... messengers in signal transduction and consequent yeast induction. Whereas thallic .... part of the structural component of regulatory proteins, protein kinase C (PKC, .... the 0.25 mM Zn2+- level separated into two subsets, with.

  1. Continuous ethanol fermentation by beer yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kida, Kenji; Morimura, Shigeru; Shima, Noriyuki; Asano, Shinichi; Yamadaki, Motozumi; Miyazawa, Toshiki

    1987-01-25

    Cooked and uncooked continuous fermentation tests and a bench-scale continuous fermentation test were carried out using a flocculating yeast, beer yeast IFO-2018, and using molasses of various origin. Heat of fermentation was measured at the same time. High productivity was found in a non-cooking continuous fermentation, but lowering of a flocculating ability was a problem. A theoretical equation for calculating the heat of fermentation was introduced and its adaptability was examined. The continuous fermentation unit was a single tank type using a tower type fermentor. The fermentor had a capacity of 0.7 l actual volume, made of glass, and consisted of the two parts, a flowing part and a precipitation/separation part. The yeast used was Saccharomyces crevisiae IFO-2018 in comparison with such yeast as S. cerevisiae IFO-0224 and S. cervisiae EP-1. (7 figs,3 tabs,21 refs)

  2. Genomic Evolution of the Ascomycete Yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Robert; Haridas, Sajeet; Salamov, Asaf; Boundy-Mills, Kyria; Goker, Markus; Hittinger, Chris; Klenk, Hans-Peter; Lopes, Mariana; Meir-Kolthoff, Jan P.; Rokas, Antonis; Rosa, Carlos; Scheuner, Carmen; Soares, Marco; Stielow, Benjamin; Wisecaver, Jennifer H.; Wolfe, Ken; Blackwell, Meredith; Kurtzman, Cletus; Grigoriev, Igor; Jeffries, Thomas

    2015-03-16

    Yeasts are important for industrial and biotechnological processes and show remarkable metabolic and phylogenetic diversity despite morphological similarities. We have sequenced the genomes of 16 ascomycete yeasts of taxonomic and industrial importance including members of Saccharomycotina and Taphrinomycotina. Phylogenetic analysis of these and previously published yeast genomes helped resolve the placement of species including Saitoella complicata, Babjeviella inositovora, Hyphopichia burtonii, and Metschnikowia bicuspidata. Moreover, we find that alternative nuclear codon usage, where CUG encodes serine instead of leucine, are monophyletic within the Saccharomycotina. Most of the yeasts have compact genomes with a large fraction of single exon genes, and a tendency towards more introns in early-diverging species. Analysis of enzyme phylogeny gives insights into the evolution of metabolic capabilities such as methanol utilization and assimilation of alternative carbon sources.

  3. The filtration properties of a dimorphic yeast

    OpenAIRE

    McCarthy, Anthony A

    2001-01-01

    A dimorphic yeast Kluyveromyces marxianu var. marxianus NRRLy2415 which exhibits a wide range of mean morphological forms was used as a model organism to investigate the role of cell morphology on the dead-end and crossflow filtration behaviour. Varying the culturing conditions produced cell suspensions of different mean morphology. Batch fermentations were used to produce yeast-like morphologies and continuous cultures produced cells more mycelial in nature. Semi-automated image analysis was...

  4. The wine and beer yeast Dekkera bruxellensis

    OpenAIRE

    Schifferdecker, Anna Judith; Dashko, Sofia; Ishchuk, Olena P.; Piškur, Jure

    2014-01-01

    Recently, the non-conventional yeast Dekkera bruxellensis has been gaining more and more attention in the food industry and academic research. This yeast species is a distant relative of Saccharomyces cerevisiae and is especially known for two important characteristics: on the one hand, it is considered to be one of the main spoilage organisms in the wine and bioethanol industry; on the other hand, it is 'indispensable' as a contributor to the flavour profile of Belgium lambic and gueuze beer...

  5. Flor Yeast: New Perspectives Beyond Wine Aging

    Science.gov (United States)

    Legras, Jean-Luc; Moreno-Garcia, Jaime; Zara, Severino; Zara, Giacomo; Garcia-Martinez, Teresa; Mauricio, Juan C.; Mannazzu, Ilaria; Coi, Anna L.; Bou Zeidan, Marc; Dequin, Sylvie; Moreno, Juan; Budroni, Marilena

    2016-01-01

    The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the aging of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air–liquid biofilm on the wine surface, which is also known as velum or flor. This behavior is due to genetic and metabolic peculiarities that differentiate flor yeast from other wine yeast. This review will focus first on the most updated data obtained through the analysis of flor yeast with -omic tools. Comparative genomics, proteomics, and metabolomics of flor and wine yeast strains are shedding new light on several features of these special yeast, and in particular, they have revealed the extent of proteome remodeling imposed by the biofilm life-style. Finally, new insights in terms of promotion and inhibition of biofilm formation through small molecules, amino acids, and di/tri-peptides, and novel possibilities for the exploitation of biofilm immobilization within a fungal hyphae framework, will be discussed. PMID:27148192

  6. Flor yeast: new perspectives beyond wine ageing

    Directory of Open Access Journals (Sweden)

    Jean-luc eLegras

    2016-04-01

    Full Text Available The most important dogma in white-wine production is the preservation of the wine aroma and the limitation of the oxidative action of oxygen. In contrast, the ageing of Sherry and Sherry-like wines is an aerobic process that depends on the oxidative activity of flor strains of Saccharomyces cerevisiae. Under depletion of nitrogen and fermentable carbon sources, these yeast produce aggregates of floating cells and form an air-liquid biofilm on the wine surface, which is also known as the velum or flor. This behaviour is due to genetic and metabolic peculiarities that differentiate flor yeast from other wine yeast. This review will focus first on the most updated data obtained through the analysis of flor yeast with -omic tools. Comparative genomics, proteomics and metabolomics of flor and wine yeast strains are shedding new light on several features of these special yeast, and in particular, they have revealed the extent of proteome remodelling imposed by the biofilm life-style. Finally, new insights in terms of promotion and inhibition of biofilm formation through small molecules, amino acids and di/tri-peptides, and novel possibilities for the exploitation of biofilm immobilisation within a fungal hyphae framework, will be discussed.

  7. Revaluation of Waste Yeast from Beer Production

    Directory of Open Access Journals (Sweden)

    Nicoleta Suruceanu

    2013-11-01

    Full Text Available Brewing yeast is an important waste product from beer production. The valorification of slurry yeast mainly consists of separation of vitamins and important nitrogen compounds. The hops compounds, one of the most important raw materials in beer technology are removed beforehand valorification. The prenylflavonoids compounds from hops are important bioactive compounds that can be revaluation with proper technology. Revaluation of prenylflavonoids from waste yeast into dietary supplement, identification and quantification of xanthohumol by HPLC method. Waste yeast from brewery pilot plant of USAMV Cluj Napoca it was dried by atomization and the powder was analyzed on xanthohumol content by HPLC method. For quantification a calibration curve it was used. The process of drying by atomisation lead to a powder product. It was used malt dextrin powder for stabilisation. The final product it was encapsulated. The xanthohumol content of powdered yeast it was 1.94 µg/ml. In conclusion the slurry yeast from beer production it is an important source of prenylflavonoids compounds.

  8. Physiological and environmental control of yeast prions.

    Science.gov (United States)

    Chernova, Tatiana A; Wilkinson, Keith D; Chernoff, Yury O

    2014-03-01

    Prions are self-perpetuating protein isoforms that cause fatal and incurable neurodegenerative disease in mammals. Recent evidence indicates that a majority of human proteins involved in amyloid and neural inclusion disorders possess at least some prion properties. In lower eukaryotes, such as yeast, prions act as epigenetic elements, which increase phenotypic diversity by altering a range of cellular processes. While some yeast prions are clearly pathogenic, it is also postulated that prion formation could be beneficial in variable environmental conditions. Yeast and mammalian prions have similar molecular properties. Crucial cellular factors and conditions influencing prion formation and propagation were uncovered in the yeast models. Stress-related chaperones, protein quality control deposits, degradation pathways, and cytoskeletal networks control prion formation and propagation in yeast. Environmental stresses trigger prion formation and loss, supposedly acting via influencing intracellular concentrations of the prion-inducing proteins, and/or by localizing prionogenic proteins to the prion induction sites via heterologous ancillary helpers. Physiological and environmental modulation of yeast prions points to new opportunities for pharmacological intervention and/or prophylactic measures targeting general cellular systems rather than the properties of individual amyloids and prions.

  9. Novel brewing yeast hybrids: creation and application.

    Science.gov (United States)

    Krogerus, Kristoffer; Magalhães, Frederico; Vidgren, Virve; Gibson, Brian

    2017-01-01

    The natural interspecies Saccharomyces cerevisiae × Saccharomyces eubayanus hybrid yeast is responsible for global lager beer production and is one of the most important industrial microorganisms. Its success in the lager brewing environment is due to a combination of traits not commonly found in pure yeast species, principally low-temperature tolerance, and maltotriose utilization. Parental transgression is typical of hybrid organisms and has been exploited previously for, e.g., the production of wine yeast with beneficial properties. The parental strain S. eubayanus has only been discovered recently and newly created lager yeast strains have not yet been applied industrially. A number of reports attest to the feasibility of this approach and artificially created hybrids are likely to have a significant impact on the future of lager brewing. De novo S. cerevisiae × S. eubayanus hybrids outperform their parent strains in a number of respects, including, but not restricted to, fermentation rate, sugar utilization, stress tolerance, and aroma formation. Hybrid genome function and stability, as well as different techniques for generating hybrids and their relative merits are discussed. Hybridization not only offers the possibility of generating novel non-GM brewing yeast strains with unique properties, but is expected to aid in unraveling the complex evolutionary history of industrial lager yeast.

  10. Yeast communities in a natural tequila fermentation.

    Science.gov (United States)

    Lachance, M A

    1995-08-01

    Fresh and cooked agave, Drosophila spp., processing equipment, agave molasses, agave extract, and fermenting must at a traditional tequila distillery (Herradura, Amatitan, Jalisco, México) were studied to gain insight on the origin of yeasts involved in a natural tequila fermentations. Five yeast communities were identified. (1) Fresh agave contained a diverse mycobiota dominated by Clavispora lusitaniae and an endemic species, Metschnikowia agaveae. (2) Drosophila spp. from around or inside the distillery yielded typical fruit yeasts, in particular Hanseniaspora spp., Pichia kluyveri, and Candida krusei. (3) Schizosaccharomyces pombe prevailed in molasses. (4) Cooked agave and extract had a considerable diversity of species, but included Saccharomyces cerevisiae. (5) Fermenting juice underwent a gradual reduction in yeast heterogeneity. Torulaspora delbrueckii, Kluyveromyces marxianus, and Hanseniaspora spp. progressively ceded the way to S. cerevisiae, Zygosaccharomyces bailii, Candida milleri, and Brettanomyces spp. With the exception of Pichia membranaefaciens, which was shared by all communities, little overlap existed. That separation was even more manifest when species were divided into distinguishable biotypes based on morphology or physiology. It is concluded that crushing equipment and must holding tanks are the main source of significant inoculum for the fermentation process. Drosophila species appear to serve as internal vectors. Proximity to fruit trees probably contributes to maintaining a substantial Drosophila community, but the yeasts found in the distillery exhibit very little similarity to those found in adjacent vegetation. Interactions involving killer toxins had no apparent direct effects on the yeast community structure.

  11. Boolean Model of Yeast Apoptosis as a Tool to Study Yeast and Human Apoptotic Regulations

    Science.gov (United States)

    Kazemzadeh, Laleh; Cvijovic, Marija; Petranovic, Dina

    2012-01-01

    Programmed cell death (PCD) is an essential cellular mechanism that is evolutionary conserved, mediated through various pathways and acts by integrating different stimuli. Many diseases such as neurodegenerative diseases and cancers are found to be caused by, or associated with, regulations in the cell death pathways. Yeast Saccharomyces cerevisiae, is a unicellular eukaryotic organism that shares with human cells components and pathways of the PCD and is therefore used as a model organism. Boolean modeling is becoming promising approach to capture qualitative behavior and describe essential properties of such complex networks. Here we present large literature-based and to our knowledge first Boolean model that combines pathways leading to apoptosis (a type of PCD) in yeast. Analysis of the yeast model confirmed experimental findings of anti-apoptotic role of Bir1p and pro-apoptotic role of Stm1p and revealed activation of the stress protein kinase Hog proposing the maximal level of activation upon heat stress. In addition we extended the yeast model and created an in silico humanized yeast in which human pro- and anti-apoptotic regulators Bcl-2 family and Valosin-contain protein (VCP) are included in the model. We showed that accumulation of Bax in silico humanized yeast shows apoptotic markers and that VCP is essential target of Akt Signaling. The presented Boolean model provides comprehensive description of yeast apoptosis network behavior. Extended model of humanized yeast gives new insights of how complex human disease like neurodegeneration can initially be tested. PMID:23233838

  12. YeastIP: a database for identification and phylogeny of Saccharomycotina yeasts.

    Science.gov (United States)

    Weiss, Stéphanie; Samson, Franck; Navarro, David; Casaregola, Serge

    2013-02-01

    With the advances in sequencing techniques, identification of ascomycetous yeasts to the species level and phylogeny reconstruction increasingly require curated and updated taxonomic information. A specific database with nucleotide sequences of the most common markers used for yeast taxonomy and phylogeny and a user-friendly interface allowing identification, taxonomy and phylogeny of yeasts species was developed. By 1 September 2012, the YeastIP database contained all the described Saccharomycotina species for which sequences used for taxonomy and phylogeny, such as D1/D2 rDNA and ITS, are available. The database interface was developed to provide a maximum of relevant information and data mining tools, including the following features: (1) the blast n program for the sequences of the YeastIP database; (2) easy retrieval of selected sequences; (3) display of the available markers for each selected group of species; and (4) a tool to concatenate marker sequences, including those provided by the user. The concatenation tool allows phylogeny reconstruction through a direct link to the Phylogeny.fr platform. YeastIP is thus a unique database in that it provides taxonomic information and guides users in their taxonomic analyses. YeastIP facilitates multigenic analysis to encourage good practice in ascomycetous yeast phylogeny (URL: http://genome.jouy.inra.fr/yeastip.). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  13. Antimycotic activity of 4-thioisosteres of flavonoids towards yeast and yeast-like microorganisms.

    Science.gov (United States)

    Buzzini, Pietro; Menichetti, Stefano; Pagliuca, Chiara; Viglianisi, Caterina; Branda, Eva; Turchetti, Benedetta

    2008-07-01

    Different substituted methoxy- and hydroxy-4-thioisosteres of flavonoids were prepared and their in vitro antimycotic activity towards yeast (Candida spp., Clavispora spp., Cryptococcus spp., Filobasidiella spp., Issatchenkia spp., Pichia spp., Kluyveromyces spp., Saccharomyces spp. and Yarrowia spp.) and yeast-like (Prototheca spp.) microorganisms was tested. Further insights in the biological activities of these antioxidant, oestrogenic and antimicrobial biomimetic derivatives were obtained.

  14. Yeast Interacting Proteins Database: YDR357C, YGL079W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available izes to the endosome; identified as a transcriptional activator in a high-throughput yeast one-hybrid assa...ome; identified as a transcriptional activator in a high-throughput yeast one-hybrid assay Rows with this pr

  15. Yeast Interacting Proteins Database: YEL005C, YGL079W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available endosome; identified as a transcriptional activator in a high-throughput yeast one-hybrid assay Rows with th...protein localizes to the endosome; identified as a transcriptional activator in a high-throughput yeast one-hybrid assay

  16. Yeast Interacting Proteins Database: YPR083W, YMR294W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available Rows with this bait as bait (1) Rows with this bait as prey (0) YMR294W JNM1 Component of the yeast dynactin...as prey (0) Prey ORF YMR294W Prey gene name JNM1 Prey description Component of the yeast dynactin complex, c

  17. Boolean model of Yeast Apoptosis as a tool to study yeast and human apoptotic regulations

    Directory of Open Access Journals (Sweden)

    Laleh eKazemzadeh

    2012-12-01

    Full Text Available Programmed cell death (PCD is an essential cellular mechanism that is evolutionary conserved, mediated through various pathways and acts by integrating different stimuli. Many diseases such as neurodegenerative diseases and cancers are found to be caused by, or associated with, regulations in the cell death pathways. Yeast Saccharomyces cerevisiae, is a unicellular eukaryotic organism that shares with human cells components and pathways of the PCD and is therefore used as a model organism. Boolean modelling is becoming promising approach to capture qualitative behaviour and describe essential properties of such complex networks. Here we present large literature-based and to our knowledge first Boolean model that combines pathways leading to apoptosis (a type of PCD in yeast. Analysis of the yeast model confirmed experimental findings of anti-apoptotic role of Bir1p and pro-apoptotic role of Stm1p and revealed activation of the stress protein kinase Hog proposing the maximal level of activation upon heat stress. In addition we extended the yeast model and created an in silico humanized yeast in which human pro- and anti-apoptotic regulators Bcl-2 family and Valosin-contain protein (VCP are included in the model. We showed that accumulation of Bax in in silico humanized yeast shows apoptotic markers and that VCP is essential target of Akt Signaling. The presented Boolean model provides comprehensive description of yeast apoptosis network behaviour. Extended model of humanized yeast gives new insights of how complex human disease like neurodegenration can initially be tested.

  18. NetPhosYeast: prediction of protein phosphorylation sites in yeast

    DEFF Research Database (Denmark)

    Ingrell, C.R.; Miller, Martin Lee; Jensen, O.N.

    2007-01-01

    We here present a neural network-based method for the prediction of protein phosphorylation sites in yeast-an important model organism for basic research. Existing protein phosphorylation site predictors are primarily based on mammalian data and show reduced sensitivity on yeast phosphorylation s...

  19. Yeast Interacting Proteins Database: YFR015C, YFR015C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...ression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into stationary ...tion, nitrogen starvation, environmental stress, and entry into stationary phase Rows with this bait as bait..., the more highly expressed yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental

  20. Terroir of yeasts? – Application of FTIR spectroscopy and molecular methods for strain typing of yeasts

    Directory of Open Access Journals (Sweden)

    Gerhards Daniel

    2015-01-01

    Full Text Available The site specific influence on wine (Terroir is an often by wine producers, consumers and scientists discussed topic in the world of wine. A study on grapes and (spontaneous fermentations from six different vineyards was done to investigate the biodiversity of yeasts and to answer the question if there is a terroir of yeast and how it could be influenced. Randomly isolated yeasts were identified by FTIR-spectroscopy and molecular methods on species and strain level. Vineyard specific yeast floras would be observed but they are not such important as expected. Only a few overlapping strain patterns would be identified during both vintages. The yeast flora of the winery had a huge impact on the spontaneous fermentations, but is not really constant and influenced by different factors from outside.

  1. Mutational analysis of yeast profilin.

    Science.gov (United States)

    Haarer, B K; Petzold, A S; Brown, S S

    1993-12-01

    We have mutated two regions within the yeast profilin gene in an effort to functionally dissect the roles of actin and phosphatidylinositol 4,5-bisphosphate (PIP2) binding in profilin function. A series of truncations was carried out at the C terminus of profilin, a region that has been implicated in actin binding. Removal of the last three amino acids nearly eliminated the ability of profilin to bind polyproline in vitro but had no dramatic in vivo effects. Thus, the extreme C terminus is implicated in polyproline binding, but the physiological relevance of this interaction is called into question. More extensive truncation, of up to eight amino acids, had in vivo effects of increasing severity and resulted in changes in conformation and expression level of the mutant profilins. However, the ability of these mutants to bind actin in vitro was not eliminated, suggesting that this region cannot be solely responsible for actin binding. We also mutagenized a region of profilin that we hypothesized might be involved in PIP2 binding. Alteration of basic amino acids in this region produced mutant profilins that functioned well in vivo. Many of these mutants, however, were unable to suppress the loss of adenylate cyclase-associated protein (Cap/Srv2p [A. Vojtek, B. Haarer, J. Field, J. Gerst, T. D. Pollard, S. S. Brown, and M. Wigler, Cell 66:497-505, 1991]), indicating that a defect could be demonstrated in vivo. In vitro assays demonstrated that the inability to suppress loss of Cap/Srv2p correlated with a defect in the interaction with actin, independently of whether PIP2 binding was reduced. Since our earlier studies of Acanthamoeba profilins suggested the importance of PIP2 binding for suppression, we conclude that both activities are implicated and that an interplay between PIP2 binding and actin binding may be important for profilin function.

  2. Baker's yeast: production of D- and L-3-hydroxy esters

    DEFF Research Database (Denmark)

    Dahl, Allan Carsten; Madsen, Jørgen Øgaard

    1998-01-01

    Baker's yeast grown under oxygen limited conditions and used in the reduction of 3-oxo esters results in a shift of the stereoselectivity of the yeast towards D-hydroxy esters as compared with ordinary baker's yeast. The highest degree of stereoselectivity was obtained with growing yeast or yeast...... harvested while growing. In contrast, the stereoselectivity was shifted towards L-hydroxy esters when the oxo esters were added slowly to ordinary baker's yeast supplied with gluconolactone as co-substrate. The reduction rate with gluconolactone was increased by active aeration. Ethyl L-(S)-3...

  3. Expression and Mutagenesis studies of Candida antactica lipase B

    OpenAIRE

    Rotticci-Mulder, Johanna C.

    2003-01-01

    Recombinant Candida antarctica lipase B was successfullyproduced in the methylotropic yeast Pichia pastoris. Thespecific activities of Candida antarctica lipase B produced inPichia pastoris and commercial Candida antarctica lipase B fromNovozymes were the same. In shake-flask cultivations theexpression levels were about 25 mg L-1. Production levels couldbe increased to 1.5 g L-1, using a fermentor. A model tosimulate growth and oxygen consumption was described. The highcell density growth cou...

  4. Chemotyping of yeast mutants using robotics.

    Science.gov (United States)

    Rieger, K J; El-Alama, M; Stein, G; Bradshaw, C; Slonimski, P P; Maundrell, K

    1999-07-01

    By now, the EUROFAN programme for the functional analysis of genes from the yeast genome has attained its cruising speed. Indeed, several hundreds of yeast mutants with no phenotype as tested by growth on standard media and no significant sequence similarity to proteins of known function are available through the efforts of various laboratories. Based on the methodology initiated during the pilot project on yeast chromosome III (Yeast 13, 1547-1562, 1997) we adapted it to High Throughput Screening (HTS), using robotics. The first 100 different gene deletions from EUROSCARF, constructed in an FY1679 strain background, were run against a collection of about 300 inhibitors. Many of these inhibitors have not been reported until now to interfere in vivo with growth of Saccharomyces cerevisiae. In the present paper we provide a list of novel growth conditions and a compilation of 49 yeast deletants (from chromosomes II, IV, VII, X, XIV, XV) corresponding to 58% of the analysed genes, with at least one clear and stringent phenotype. The majority of these deletants are sensitive to one or two compounds (monotropic phenotype) while a distinct subclass of deletants displays a hyper-pleiotropic phenotype with sensitivities to a dozen or more compounds. Therefore, chemotyping of unknown genes with a large spectrum of drugs opens new vistas for a more in-depth functional analysis and a more precise definition of molecular targets.

  5. Extension of yeast chronological lifespan by methylamine.

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    Full Text Available BACKGROUND: Chronological aging of yeast cells is commonly used as a model for aging of human post-mitotic cells. The yeast Saccharomyces cerevisiae grown on glucose in the presence of ammonium sulphate is mainly used in yeast aging research. We have analyzed chronological aging of the yeast Hansenula polymorpha grown at conditions that require primary peroxisome metabolism for growth. METHODOLOGY/PRINCIPAL FINDINGS: The chronological lifespan of H. polymorpha is strongly enhanced when cells are grown on methanol or ethanol, metabolized by peroxisome enzymes, relative to growth on glucose that does not require peroxisomes. The short lifespan of H. polymorpha on glucose is mainly due to medium acidification, whereas most likely ROS do not play an important role. Growth of cells on methanol/methylamine instead of methanol/ammonium sulphate resulted in further lifespan enhancement. This was unrelated to medium acidification. We show that oxidation of methylamine by peroxisomal amine oxidase at carbon starvation conditions is responsible for lifespan extension. The methylamine oxidation product formaldehyde is further oxidized resulting in NADH generation, which contributes to increased ATP generation and reduction of ROS levels in the stationary phase. CONCLUSION/SIGNIFICANCE: We conclude that primary peroxisome metabolism enhanced chronological lifespan of H. polymorpha. Moreover, the possibility to generate NADH at carbon starvation conditions by an organic nitrogen source supports further extension of the lifespan of the cell. Consequently, the interpretation of CLS analyses in yeast should include possible effects on the energy status of the cell.

  6. Yeast flocculation: what brewers should know.

    Science.gov (United States)

    Verstrepen, K J; Derdelinckx, G; Verachtert, H; Delvaux, F R

    2003-05-01

    For many industrial applications in which the yeast Saccharomyces cerevisiae is used, e.g. beer, wine and alcohol production, appropriate flocculation behaviour is certainly one of the most important characteristics of a good production strain. Yeast flocculation is a very complex process that depends on the expression of specific flocculation genes such as FLO1, FLO5, FLO8 and FLO11. The transcriptional activity of the flocculation genes is influenced by the nutritional status of the yeast cells as well as other stress factors. Flocculation is also controlled by factors that affect cell wall composition or morphology. This implies that, during industrial fermentation processes, flocculation is affected by numerous parameters such as nutrient conditions, dissolved oxygen, pH, fermentation temperature, and yeast handling and storage conditions. Theoretically, rational use of these parameters offers the possibility of gaining control over the flocculation process. However, flocculation is a very strain-specific phenomenon, making it difficult to predict specific responses. In addition, certain genes involved in flocculation are extremely variable, causing frequent changes in the flocculation profile of some strains. Therefore, both a profound knowledge of flocculation theory as well as close monitoring and characterisation of the production strain are essential in order to gain maximal control over flocculation. In this review, the various parameters that influence flocculation in real-scale brewing are critically discussed. However, many of the conclusions will also be useful in various other industrial processes where control over yeast flocculation is desirable.

  7. Yeast fuel cell: Application for desalination

    Science.gov (United States)

    Mardiana, Ummy; Innocent, Christophe; Cretin, Marc; Buchari, Buchari; Gandasasmita, Suryo

    2016-02-01

    Yeasts have been implicated in microbial fuel cells as biocatalysts because they are non-pathogenic organisms, easily handled and robust with a good tolerance in different environmental conditions. Here we investigated baker's yeast Saccharomyces cerevisiae through the oxidation of glucose. Yeast was used in the anolyte, to transfer electrons to the anode in the presence of methylene blue as mediator whereas K3Fe(CN)6 was used as an electron acceptor for the reduction reaction in the catholyte. Power production with biofuel cell was coupled with a desalination process. The maximum current density produced by the cell was 88 mA.m-2. In those conditions, it was found that concentration of salt was removed 64% from initial 0.6 M after 1-month operation. This result proves that yeast fuel cells can be used to remove salt through electrically driven membrane processes and demonstrated that could be applied for energy production and desalination. Further developments are in progress to improve power output to make yeast fuel cells applicable for water treatment.

  8. Yeasts associated with Sardinian ewe's dairy products.

    Science.gov (United States)

    Cosentino, S; Fadda, M E; Deplano, M; Mulargia, A F; Palmas, F

    2001-09-19

    In the present work, the occurrence of yeasts in different types of typical Sardinian ewe's cheeses (32 samples of pecorino, 32 of caciotta, 40 of feta, 56 of ricotta) was determined. For the strains isolated the following properties were studied: proteolytic and lipolytic activities, the ability to grow at different temperatures, different concentrations of salt, and to assimilate and/or ferment compounds like lactate, citrate, lactose, glucose, galactose, lactic acid. Of 160 samples analysed, 76.2% yielded growth of yeasts. Yeast counts showed a certain variability among the samples. The highest levels were observed in caciotta and feta cheeses. A total of 281 strains belonging to 16 genera and 25 species were identified. In general, Debaryomyces hansenii was the dominant species, representing 28.8% of the total isolates. Other frequently appearing species were Geotrichum candidum, Kluyveromyces lactis and K. marxianus. Other genera encountered were Pichia, Candida, Dekkera, Yarrowia and Rhodotorula. With regard to the biochemical and technological properties of the yeasts, only K. lactis, K. marxianus and Dek. anomala assimilated and fermented lactose, whereas the majority of the species assimilated lactic acid. The assimilation of citrate was a characteristic of D. hansenii, R. rubra and Y. lipolytica. On the whole, the yeasts were weakly proteolytic while lipolytic activity was present in several species. A high percentage of strains showed a certain tolerance to low temperatures while only some strains of D. hansenii and K. lactis were able to grow at a 10% NaCl concentration.

  9. Isolation and characterization of oenological yeast.

    Directory of Open Access Journals (Sweden)

    Fatbardha Lamce

    2013-12-01

    Full Text Available Alcoholic fermentation is carried out by all microorganisms presented in must, which vary by technological characteristics of interest to oenology. So far, in Albania the fermentation is spontaneous and not directed, resulting in an absence of a standard product. The object of the present study is the isolation, identification and determination of yeasts, isolated in different phases of fermentation of musts from different varieties of grapes, with the purpose of selecting autochthonous yeasts for a directed fermentation. In the present study were isolated 14 strains, with P.D.A. and Y.M.A. mediums. After isolation, purity controls were made to the strains through cultivation and re-cultivation of them in Petri dish, and also, by running a stereomicroscopic and microscopic examination. Classification and identification of yeast strains in genus and species were based on macro-morphological characteristics of the colonies. Then, morphological characteristics of the cell were observed as an important taxonomic indicator. For the determination of the physiological and biochemical characteristics of yeasts, the assimilation of sugars and the fermenting ability of yeast were used. At the end were isolated and identified 9 strains of the genus Saccharomyces, 1 strain of the genus Schizosaccharomyces, 2 strains of the genus Brettanomyces, 2 strains of the genus Kloeckera. These will serve to further work towards their selection based on their fermenting technological characteristics.

  10. Radiodiagnosis of yeast alveolitis (a clinicoexperimental study)

    Energy Technology Data Exchange (ETDEWEB)

    Amosov, I.S.; Smirnov, V.A.

    A clinicoroetgenological study was made of 115 workers engaged in yeast production for different periods of time. Disorders of respiration biomechanics were revealed depending on the period of service. These data were obtained as a result of the use of roentgenopneumopolygraphy. An experimental study was conducted to establish the nature of lesions in the bronchopulmonary system in allergic alveolitis. The effect of finely divided yeast dust on the bronchopulmonary system was studied on 132 guinea-pigs usinq microbronchography and morphological examination. As a result of the study it has been established that during the inhalation of yeast dust, noticeable dystrophy of the bronchi develops, the sizes of alveoli enlarge and part of them undergo emphysematous distension with rupture of the interalveolar septa. In the course of the study, it has been shown that yeast alveolitis develops after many years of work. The clinical symptoms are non-specific and insignificant. X-ray and morphological changes are followed by the physical manifestations of yeast alveolitis.

  11. Probiotic Properties of Non-Saccharomyces Yeasts

    DEFF Research Database (Denmark)

    Smith, Ida Mosbech

    to harmless luminal substances is a key feature of the intestinal immune system. In this context, dendritic cells (DCs) present in the tissues lining the human gut are central players involved in microbial sensing and shaping of appropriate adaptive immune responses. Probiotics are live microorganisms which...... when administered in adequate amounts confer a health benefit on the host. While the majority of probiotic microorganisms studied to date are lactic acid bacteria, research in yeasts with potentially beneficial influences on human health has mainly revolved around Saccharomyces boulardii. This yeast...... has shown a positive impact on disease outcome in clinical studies of inflammatory bowel disease, indicating an ability of S. boulardii to influence human immune responses underlying intestinal inflammation. Consequent to this focus on S. boulardii as the fundamental probiotic yeast, very little...

  12. Probiotic Properties of Non-Saccharomyces Yeasts

    DEFF Research Database (Denmark)

    Smith, Ida Mosbech

    to harmless luminal substances is a key feature of the intestinal immune system. In this context, dendritic cells (DCs) present in the tissues lining the human gut are central players involved in microbial sensing and shaping of appropriate adaptive immune responses. Probiotics are live microorganisms which...... when administered in adequate amounts confer a health benefit on the host. While the majority of probiotic microorganisms studied to date are lactic acid bacteria, research in yeasts with potentially beneficial influences on human health has mainly revolved around Saccharomyces boulardii. This yeast...... has shown a positive impact on disease outcome in clinical studies of inflammatory bowel disease, indicating an ability of S. boulardii to influence human immune responses underlying intestinal inflammation. Consequent to this focus on S. boulardii as the fundamental probiotic yeast, very little...

  13. Flux control through protein phosphorylation in yeast

    DEFF Research Database (Denmark)

    Chen, Yu; Nielsen, Jens

    2016-01-01

    describe the development of phosphoproteomics in yeast as well as approaches to analysing the phosphoproteomics data. Finally, we focus on integrated analyses with other omics data sets and genome-scale metabolic models. Despite the advances, future studies improving both experimental technologies......Protein phosphorylation is one of the most important mechanisms regulating metabolism as it can directly modify metabolic enzymes by the addition of phosphate groups. Attributed to such a rapid and reversible mechanism, cells can adjust metabolism rapidly in response to temporal changes. The yeast...... as well as identify mechanisms underlying human metabolic diseases. Here we collect functional phosphorylation events of 41 enzymes involved in yeast metabolism and demonstrate functional mechanisms and the application of this information in metabolic engineering. From a systems biology perspective, we...

  14. Metallic Biosorption Using Yeasts in Continuous Systems

    Directory of Open Access Journals (Sweden)

    Karla Miriam Hernández Mata

    2013-01-01

    Full Text Available Mining effluents were found to be the main source of pollution by heavy metals of the surface water in the San Pedro River in Sonora, Mexico. The overall objective of this study was to determine the biosorption of Zn, Cu, Mn, and Fe with yeasts isolated from San Pedro River in a continuous system. The tests conducted in two reactors packed with zeolite connected in series. The first reactor was inoculated mixing two yeasts species, and the effluent of the first reactor was fed to second reactor. Subsequently, the first reactor was fed with contaminated water of San Pedro River and effluent from this was the second reactor influent. After 40 days of the experiment a reduction of 81.5% zinc, 76.5% copper, manganese 95.5%, and 99.8% of iron was obtained. These results show that the selected yeasts are capable of biosorbing zinc, copper, manganese, and iron under these conditions.

  15. Complete biosynthesis of opioids in yeast.

    Science.gov (United States)

    Galanie, Stephanie; Thodey, Kate; Trenchard, Isis J; Filsinger Interrante, Maria; Smolke, Christina D

    2015-09-04

    Opioids are the primary drugs used in Western medicine for pain management and palliative care. Farming of opium poppies remains the sole source of these essential medicines, despite diverse market demands and uncertainty in crop yields due to weather, climate change, and pests. We engineered yeast to produce the selected opioid compounds thebaine and hydrocodone starting from sugar. All work was conducted in a laboratory that is permitted and secured for work with controlled substances. We combined enzyme discovery, enzyme engineering, and pathway and strain optimization to realize full opiate biosynthesis in yeast. The resulting opioid biosynthesis strains required the expression of 21 (thebaine) and 23 (hydrocodone) enzyme activities from plants, mammals, bacteria, and yeast itself. This is a proof of principle, and major hurdles remain before optimization and scale-up could be achieved. Open discussions of options for governing this technology are also needed in order to responsibly realize alternative supplies for these medically relevant compounds.

  16. Degradation of 5-hydroxymethylfurfural during yeast fermentation.

    Science.gov (United States)

    Akıllıoglu, Halise Gül; Mogol, Burçe Ataç; Gökmen, Vural

    2011-12-01

    5-Hydroxymethyl furfural (HMF) may occur in malt in high quantities depending on roasting conditions. However, the HMF content of different types of beers is relatively low, indicating its potential for degradation during fermentation. This study investigates the degradation kinetics of HMF in wort during fermentation by Saccharomyces cerevisiae. The results indicated that HMF decreased exponentially as fermentation progressed. The first-order degradation rate of HMF was 0.693 × 10(-2) and 1.397 × 10(-2)min(-1) for wort and sweet wort, respectively, indicating that sugar enhances the activity of yeasts. In wort, HMF was converted into hydroxymethyl furfuryl alcohol by yeasts with a high yield (79-84% conversion). Glucose and fructose were utilised more rapidly by the yeasts in dark roasted malt than in pale malt (pfermentation medium increases this activity.

  17. Bioadsorption strategies with yeast molecular display technology.

    Science.gov (United States)

    Shibasaki, Seiji; Ueda, Mitsuyoshi

    2014-01-01

    Molecular display techniques using microbial cell surfaces have been widely developed in the past twenty years, and are useful tools as whole cell catalysts for various applications such as bioconversion, bioremediation, biosensing, and the screening system of protein libraries. Furthermore, different types of microbial cells among eukaryotic and prokaryotic strains have been investigated for their use in surface display technologies. Recently, several kinds of protein-displaying yeasts have been utilized as bioadsorbents in this platform technology. In particular, these trials have successfully expanded the possibility of applications to metal binding, affinity purification, and receptor-ligand interaction by using the yeast cell surface. In this mini review, we describe the general principles of molecular display technology using yeast cells and its applications, with a particular focus on bioadsorption.

  18. New yeasts-new brews: modern approaches to brewing yeast design and development.

    Science.gov (United States)

    Gibson, B; Geertman, J-M A; Hittinger, C T; Krogerus, K; Libkind, D; Louis, E J; Magalhães, F; Sampaio, J P

    2017-06-01

    The brewing industry is experiencing a period of change and experimentation largely driven by customer demand for product diversity. This has coincided with a greater appreciation of the role of yeast in determining the character of beer and the widespread availability of powerful tools for yeast research. Genome analysis in particular has helped clarify the processes leading to domestication of brewing yeast and has identified domestication signatures that may be exploited for further yeast development. The functional properties of non-conventional yeast (both Saccharomyces and non-Saccharomyces) are being assessed with a view to creating beers with new flavours as well as producing flavoursome non-alcoholic beers. The discovery of the psychrotolerant S. eubayanus has stimulated research on de novo S. cerevisiae × S. eubayanus hybrids for low-temperature lager brewing and has led to renewed interest in the functional importance of hybrid organisms and the mechanisms that determine hybrid genome function and stability. The greater diversity of yeast that can be applied in brewing, along with an improved understanding of yeasts' evolutionary history and biology, is expected to have a significant and direct impact on the brewing industry, with potential for improved brewing efficiency, product diversity and, above all, customer satisfaction. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Yeast Actin-Related Protein ARP6 Negatively Regulates Agrobacterium-Mediated Transformation of Yeast Cell

    Directory of Open Access Journals (Sweden)

    Yumei Luo

    2015-01-01

    Full Text Available The yeasts, including Saccharomyces cerevisiae and Pichia pastoris, are single-cell eukaryotic organisms that can serve as models for human genetic diseases and hosts for large scale production of recombinant proteins in current biopharmaceutical industry. Thus, efficient genetic engineering tools for yeasts are of great research and economic values. Agrobacterium tumefaciens-mediated transformation (AMT can transfer T-DNA into yeast cells as a method for genetic engineering. However, how the T-DNA is transferred into the yeast cells is not well established yet. Here our genetic screening of yeast knockout mutants identified a yeast actin-related protein ARP6 as a negative regulator of AMT. ARP6 is a critical member of the SWR1 chromatin remodeling complex (SWR-C; knocking out some other components of the complex also increased the transformation efficiency, suggesting that ARP6 might regulate AMT via SWR-C. Moreover, knockout of ARP6 led to disruption of microtubule integrity, higher uptake and degradation of virulence proteins, and increased DNA stability inside the cells, all of which resulted in enhanced transformation efficiency. Our findings have identified molecular and cellular mechanisms regulating AMT and a potential target for enhancing the transformation efficiency in yeast cells.

  20. Yeasts and yeast-like organisms associated with fruits and blossoms of different fruit trees.

    Science.gov (United States)

    Vadkertiová, Renáta; Molnárová, Jana; Vránová, Dana; Sláviková, Elena

    2012-12-01

    Yeasts are common inhabitants of the phyllosphere, but our knowledge of their diversity in various plant organs is still limited. This study focused on the diversity of yeasts and yeast-like organisms associated with matured fruits and fully open blossoms of apple, plum, and pear trees, during 2 consecutive years at 3 localities in southwest Slovakia. The occurrence of yeasts and yeast-like organisms in fruit samples was 2½ times higher and the yeast community more diverse than that in blossom samples. Only 2 species (Aureobasidium pullulans and Metschnikowia pulcherrima) occurred regularly in the blossom samples, whereas Galactomyces candidus, Hanseniaspora guilliermondii, Hanseniaspora uvarum, M. pulcherrima, Pichia kluyveri, Pichia kudriavzevii, and Saccharomyces cerevisiae were the most frequently isolated species from the fruit samples. The ratio of the number of samples where only individual species were present to the number of samples where 2 or more species were found (consortium) was counted. The occurrence of individual species in comparison with consortia was much higher in blossom samples than in fruit samples. In the latter, consortia predominated. Aureobasidium pullulans, M. pulcherrima, and S. cerevisiae, isolated from both the fruits and blossoms, can be considered as resident yeast species of various fruit tree species cultivated in southwest Slovakia localities.

  1. Yeast Actin-Related Protein ARP6 Negatively Regulates Agrobacterium-Mediated Transformation of Yeast Cell.

    Science.gov (United States)

    Luo, Yumei; Chen, Zikai; Zhu, Detu; Tu, Haitao; Pan, Shen Quan

    2015-01-01

    The yeasts, including Saccharomyces cerevisiae and Pichia pastoris, are single-cell eukaryotic organisms that can serve as models for human genetic diseases and hosts for large scale production of recombinant proteins in current biopharmaceutical industry. Thus, efficient genetic engineering tools for yeasts are of great research and economic values. Agrobacterium tumefaciens-mediated transformation (AMT) can transfer T-DNA into yeast cells as a method for genetic engineering. However, how the T-DNA is transferred into the yeast cells is not well established yet. Here our genetic screening of yeast knockout mutants identified a yeast actin-related protein ARP6 as a negative regulator of AMT. ARP6 is a critical member of the SWR1 chromatin remodeling complex (SWR-C); knocking out some other components of the complex also increased the transformation efficiency, suggesting that ARP6 might regulate AMT via SWR-C. Moreover, knockout of ARP6 led to disruption of microtubule integrity, higher uptake and degradation of virulence proteins, and increased DNA stability inside the cells, all of which resulted in enhanced transformation efficiency. Our findings have identified molecular and cellular mechanisms regulating AMT and a potential target for enhancing the transformation efficiency in yeast cells.

  2. EFFECTS OF MILLET MALT WORT ON BREWER'S YEAST

    African Journals Online (AJOL)

    BSN

    Barely malt has been the brewers choice for beer fermentation. (1'. ... Peptone yeast extract glucose broth prepared according to the methods of .... satisfactory as the crop of yeast recovered was high and responded well in fermentation to the ...

  3. Autophagy: one more Nobel Prize for yeast.

    Science.gov (United States)

    Zimmermann, Andreas; Kainz, Katharina; Andryushkova, Aleksandra; Hofer, Sebastian; Madeo, Frank; Carmona-Gutierrez, Didac

    2016-12-05

    The recent announcement of the 2016 Nobel Prize in Physiology or Medicine, awarded to Yoshinori Ohsumi for the discoveries of mechanisms governing autophagy, underscores the importance of intracellular degradation and recycling. At the same time, it further cements yeast, in which this field decisively developed, as a prolific model organism. Here we provide a quick historical overview that mirrors both the importance of autophagy as a conserved and essential process for cellular life and death as well as the crucial role of yeast in its mechanistic characterization.

  4. Autophagy: one more Nobel Prize for yeast

    Directory of Open Access Journals (Sweden)

    Andreas Zimmermann

    2016-12-01

    Full Text Available The recent announcement of the 2016 Nobel Prize in Physiology or Medicine, awarded to Yoshinori Ohsumi for the discoveries of mechanisms governing autophagy, underscores the importance of intracellular degradation and recycling. At the same time, it further cements yeast, in which this field decisively developed, as a prolific model organism. Here we provide a quick historical overview that mirrors both the importance of autophagy as a conserved and essential process for cellular life and death as well as the crucial role of yeast in its mechanistic characterization.

  5. Molecular breeding of the yeast Saccharomyces.

    OpenAIRE

    大嶋, 泰治; Yasuji, Oshima; 大阪大学工学部応用生物工学科; Department of Biotechnology, faculty of Engineering, Kansai University

    1993-01-01

    In 1951,shortly after the end of World War II, I entered Osaka University to study yeast biology in brewing technology. This was due to my father's wish, in part, as well as to my own interest, though I had to give up the possibility of pursuing my long-cherished desire to be an aeronautical engineer. Because my family owns a small sake factory locally, I was already somewhat familiar with yeast, and had some interest in this simple organism. When I became a senior student in the Department o...

  6. Analysis of RNA metabolism in fission yeast

    DEFF Research Database (Denmark)

    Wise, Jo Ann; Nielsen, Olaf

    2017-01-01

    Here we focus on the biogenesis and function of messenger RNA (mRNA) in fission yeast cells. Following a general introduction that also briefly touches on other classes of RNA, we provide an overview of methods used to analyze mRNAs throughout their life cycles.......Here we focus on the biogenesis and function of messenger RNA (mRNA) in fission yeast cells. Following a general introduction that also briefly touches on other classes of RNA, we provide an overview of methods used to analyze mRNAs throughout their life cycles....

  7. Fission Yeast Cell Cycle Synchronization Methods.

    Science.gov (United States)

    Tormos-Pérez, Marta; Pérez-Hidalgo, Livia; Moreno, Sergio

    2016-01-01

    Fission yeast cells can be synchronized by cell cycle arrest and release or by size selection. Cell cycle arrest synchronization is based on the block and release of temperature-sensitive cell cycle mutants or treatment with drugs. The most widely used approaches are cdc10-129 for G1; hydroxyurea (HU) for early S-phase; cdc25-22 for G2, and nda3-KM311 for mitosis. Cells can also be synchronized by size selection using centrifugal elutriation or a lactose gradient. Here we describe the methods most commonly used to synchronize fission yeast cells.

  8. Genetic diversity of the yeast Candida utilis.

    Science.gov (United States)

    Stoltenburg, R; Klinner, U; Ritzerfeld, P; Zimmermann, M; Emeis, C C

    1992-12-01

    The electrophoretic karyotypes and some mtDNA restriction fragment patterns of 13 strains of Candida utilis and one strain of Hansenula jadinii were compared. PFGE separations revealed remarkable chromosome length polymorphisms between two groups of strains suggesting that perhaps they do not belong to the same species. However, all strains had the same or similar EcoRI, HindIII and BamHI mtDNA restriction patterns. The mtDNA genomes had an average size range of 55 kb. These results support the supposition that C. utilis is a yeast with a highly variable electrophoretic karyotype as already known for another imperfect yeast species, Candida albicans.

  9. Occurrence of Killer Yeast Strains in Fruit and Berry Wine Yeast Populations

    Directory of Open Access Journals (Sweden)

    Gintare Gulbiniene

    2004-01-01

    Full Text Available Apple, cranberry, chokeberry and Lithuanian red grape wine yeast populations were used for the determination of killer yeast occurrence. According to the tests of the killer characteristics and immunity the isolated strains were divided into seven groups. In this work the activity of killer toxins purified from some typical strains was evaluated. The analysed strains produced different amounts of active killer toxin and some of them possessed new industrially significant killer properties. Total dsRNA extractions in 11 killer strains of yeast isolated from spontaneous fermentations revealed that the molecular basis of the killer phenomenon was not only dsRNAs, but also unidentified genetic determinants.

  10. Evaluation of fungichrom 1: A new yeast identification system

    OpenAIRE

    Umabala P; Satheeshkumar T; Lakshmi V

    2002-01-01

    Advances in anti-fungal therapy necessitate the need for accurate identification of fungi especially yeasts to their species level for more effective management. Unlike the time consuming conventional methods of yeast identification using fermentation and assimilation patterns of various carbohydrates, the new commercialized yeast identification systems are simpler, rapid and are particularly easy to interpret. In our study, a new colorimetric yeast identification system-Fungichrom 1(Internat...

  11. The significance of peroxisomes in methanol metabolism in methylotrophic yeast

    NARCIS (Netherlands)

    Klei, Ida J. van der; Yurimoto, Hiroya; Sakai, Yasuyoshi; Veenhuis, Marten

    2006-01-01

    The capacity to use methanol as sole source of carbon and energy is restricted to relatively few yeast species. This may be related to the low efficiency of methanol metabolism in yeast, relative to that of prokaryotes. This contribution describes the details of methanol metabolism in yeast and focu

  12. Effect of yeast extract and chitosan on shoot proliferation ...

    African Journals Online (AJOL)

    Jane

    2011-08-01

    Aug 1, 2011 ... inhibition of leaf-development in the in vitro plantlets of C. mangga (Figure 1). .... yeast 2.0 yeast 3.5 yeast 5.0. Incubation time (minutes). D. P. P. H fre e rad ic al scave n g in g a .... example of rapid development. Pharmazie.

  13. Adhesive interactions between medically important yeasts and bacteria

    NARCIS (Netherlands)

    Millsap, KW; van der Mei, HC; Busscher, HJ; Bos, R.R.M.

    1998-01-01

    Yeasts are being increasingly identified as important organisms in human infections. Adhesive interactions between yeasts and bacteria may contribute to yeast retention al body sites. Methods for studying adhesive interactions between bacterial strains are well known, and range from simple macroscop

  14. Comparative Performance of the RapID Yeast Plus System and the API 20C AUX Clinical Yeast System

    OpenAIRE

    Smith, Michael B; Dunklee, Daisy; Vu, Hangna; Woods, Gail L.

    1999-01-01

    The performance of the RapID Yeast Plus System (Innovative Diagnostic Systems, Norcross, Ga.), a 4-h micropanel using single-substrate enzymatic test reactions, was compared with that of the API 20C AUX Clinical Yeast System (bioMerieux Vitek, Hazelwood, Mo.), a 48- to 72-h carbohydrate assimilation panel. Two hundred twenty-five yeasts, yeast-like fungi, and algae, comprising 28 species and including 30 isolates of Cryptococcus neoformans, an important pathogen not tested in appreciable numb...

  15. Fission yeast meets a legend in Kobe: report of the Eighth International Fission Yeast Meeting.

    Science.gov (United States)

    Asakawa, Haruhiko; Yamamoto, Takaharu G; Hiraoka, Yasushi

    2015-12-01

    The Eighth International Fission Yeast Meeting, which was held at Ikuta Shrine Hall in Kobe, Japan, from 21 to 26 June 2015, was attended by 327 fission yeast researchers from 25 countries (190 overseas and 137 domestic participants). At this meeting, 124 talks were held and 145 posters were presented. In addition, newly developed database tools were introduced to the community during a workshop. Researchers shared cutting-edge knowledge across broad fields of study, ranging from molecules to evolution, derived from the superior model organism commonly used within the fission yeast community. Intensive discussions and constructive suggestions generated in this meeting will surely advance the understanding of complex biological systems in fission yeast, extending to general eukaryotes.

  16. Yeast Interacting Proteins Database: YFR015C, YLR258W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into statio

  17. Dynamic changes in brewing yeast cells in culture revealed by statistical analyses of yeast morphological data.

    Science.gov (United States)

    Ohnuki, Shinsuke; Enomoto, Kenichi; Yoshimoto, Hiroyuki; Ohya, Yoshikazu

    2014-03-01

    The vitality of brewing yeasts has been used to monitor their physiological state during fermentation. To investigate the fermentation process, we used the image processing software, CalMorph, which generates morphological data on yeast mother cells and bud shape, nuclear shape and location, and actin distribution. We found that 248 parameters changed significantly during fermentation. Successive use of principal component analysis (PCA) revealed several important features of yeast, providing insight into the dynamic changes in the yeast population. First, PCA indicated that much of the observed variability in the experiment was summarized in just two components: a change with a peak and a change over time. Second, PCA indicated the independent and important morphological features responsible for dynamic changes: budding ratio, nucleus position, neck position, and actin organization. Thus, the large amount of data provided by imaging analysis can be used to monitor the fermentation processes involved in beer and bioethanol production.

  18. Yeast Interacting Proteins Database: YFR015C, YJL137C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...pression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into stationary

  19. Antarctic Yeasts: Biodiversity and Potential Applications

    Science.gov (United States)

    Shivaji, S.; Prasad, G. S.

    This review is an attempt in cataloguing the diversity of yeasts in Antarctica, highlight their biotechnological potential and understand the basis of adaptation to low temperature. As of now several psychrophilic and psychrotolerant yeasts from Antarctic soils and marine waters have been characterized with respect to their growth characteristics, ecological distribution and taxonomic significance. Interestingly most of these species belonged to basidiomycetous yeasts which as a group are known for their ability to circumvent and survive under stress conditions. Simultaneously their possible role as work horses in the biotechnological industry was recognized due to their ability to produce novel enzymes and biomolecules such as agents for the breakdown of xenobiotics, and novel pharmaceutical chemi cals. The high activity of psychrophilic enzymes at low and moderate temperatures offers potential economic benefits. As of now lipases from Pseudozyma antarctica have been extensively studied to understand their unique thermal stability at 90°C and also because of its use in the pharmaceutical, agriculture, food, cosmetics and chemical industry. A few of the other enzymes which have been studied include extracellular alpha-amylase and glucoamylase from the yeast Pseudozyma antarctica (Candida antarctica), an extra-cellular protease from Cryptococcus humicola, an aspartyl proteinase from Cryptococcus humicola, a novel extracellular subtilase from Leucosporidium antarcticum, and a xylanase from Cryptococcus adeliensis

  20. Modeling diauxic glycolytic oscillations in yeast

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Sørensen, Preben Graae

    2010-01-01

    Glycolytic oscillations in a stirred suspension of starved yeast cells is an excellent model system for studying the dynamics of metabolic switching in living systems. In an open-flow system the oscillations can be maintained indefinitely at a constant operating point where they can be characteri...

  1. Resurrecting ancestral alcohol dehydrogenases from yeast.

    Science.gov (United States)

    Thomson, J Michael; Gaucher, Eric A; Burgan, Michelle F; De Kee, Danny W; Li, Tang; Aris, John P; Benner, Steven A

    2005-06-01

    Modern yeast living in fleshy fruits rapidly convert sugars into bulk ethanol through pyruvate. Pyruvate loses carbon dioxide to produce acetaldehyde, which is reduced by alcohol dehydrogenase 1 (Adh1) to ethanol, which accumulates. Yeast later consumes the accumulated ethanol, exploiting Adh2, an Adh1 homolog differing by 24 (of 348) amino acids. As many microorganisms cannot grow in ethanol, accumulated ethanol may help yeast defend resources in the fruit. We report here the resurrection of the last common ancestor of Adh1 and Adh2, called Adh(A). The kinetic behavior of Adh(A) suggests that the ancestor was optimized to make (not consume) ethanol. This is consistent with the hypothesis that before the Adh1-Adh2 duplication, yeast did not accumulate ethanol for later consumption but rather used Adh(A) to recycle NADH generated in the glycolytic pathway. Silent nucleotide dating suggests that the Adh1-Adh2 duplication occurred near the time of duplication of several other proteins involved in the accumulation of ethanol, possibly in the Cretaceous age when fleshy fruits arose. These results help to connect the chemical behavior of these enzymes through systems analysis to a time of global ecosystem change, a small but useful step towards a planetary systems biology.

  2. Ethanol tolerance of immobilized brewers' yeast cells.

    Science.gov (United States)

    Norton, S; Watson, K; D'Amore, T

    1995-04-01

    A method based on the survival of yeast cells subjected to an ethanol or heat shock was utilized to compare the stress resistance of free and carrageenan-immobilized yeast cells. Results demonstrated a significant increase of yeast survival against ethanol for immobilized cells as compared to free cells, while no marked difference in heat resistance was observed. When entrapped cells were released by mechanical disruption of the gel beads and submitted to the same ethanol stress, they exhibited a lower survival rate than entrapped cells, but a similar or slightly higher survival rate than free cells. The incidence of ethanol- or heat-induced respiratory-deficient mutants of entrapped cells was equivalent to that of control or non-stressed cells (1.3 +/- 0.5%) whereas ethanol- and heat-shocked free and released cells exhibited between 4.4% and 10.9% average incidence of respiration-deficient mutants. It was concluded that the carrageenan gel matrix provided a protection against ethanol, and that entrapped cells returned to normal physiological behaviour as soon as they were released. The cell growth rate was a significant factor in the resistance of yeast to high ethanol concentrations. The optimum conditions to obtain reliable and reproducible results involved the use of slow-growing cells after exhaustion of the sugar substrate.

  3. Centromeric DNA Facilitates Nonconventional Yeast Genetic Engineering.

    Science.gov (United States)

    Cao, Mingfeng; Gao, Meirong; Lopez-Garcia, Carmen Lorena; Wu, Yutong; Seetharam, Arun Somwarpet; Severin, Andrew Josef; Shao, Zengyi

    2017-08-18

    Many nonconventional yeast species have highly desirable features that are not possessed by model yeasts, despite that significant technology hurdles to effectively manipulate them lay in front. Scheffersomyces stipitis is one of the most important exemplary nonconventional yeasts in biorenewables industry, which has a high native xylose utilization capacity. Recent study suggested its much better potential than Saccharomyces cerevisiae as a well-suited microbial biomanufacturing platform for producing high-value compounds derived from shikimate pathway, many of which are associated with potent nutraceutical or pharmaceutical properties. However, the broad application of S. stipitis is hampered by the lack of stable episomal expression platforms and precise genome-editing tools. Here we report the success in pinpointing the centromeric DNA as the partitioning element to guarantee stable extra-chromosomal DNA segregation. The identified centromeric sequence not only stabilized episomal plasmid, enabled homogeneous gene expression, increased the titer of a commercially relevant compound by 3-fold, and also dramatically increased gene knockout efficiency from <1% to more than 80% with the expression of CRISPR components on the new stable plasmid. This study elucidated that establishment of a stable minichromosome-like expression platform is key to achieving functional modifications of nonconventional yeast species in order to expand the current collection of microbial factories.

  4. Uncommon opportunistic yeast bloodstream infections from Qatar

    NARCIS (Netherlands)

    Taj-Aldeen, S.J.; AbdulWahab, A.; Kolecka, A.; Deshmukh, A.; Meis, J.F.G.M.; Boekhout, T.

    2014-01-01

    Eleven uncommon yeast species that are associated with high mortality rates irrespective of antifungal therapy were isolated from 17/187 (201 episodes) pediatric and elderly patients with fungemia from Qatar. The samples were taken over a 6-year period (January 2004-December 2010). Isolated species

  5. Cell biology of homologous recombination in yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine Valerie; Rothstein, Rodney; Lisby, Michael

    2011-01-01

    Homologous recombination is an important pathway for error-free repair of DNA lesions, such as single- and double-strand breaks, and for rescue of collapsed replication forks. Here, we describe protocols for live cell imaging of single-lesion recombination events in the yeast Saccharomyces...

  6. An Engineered Yeast Efficiently Secreting Penicillin

    NARCIS (Netherlands)

    Gidijala, Loknath; Kiel, Jan A. K. W.; Douma, Rutger D.; Seifar, Reza M.; van Gulik, Walter M.; Bovenberg, Roel A. L.; Veenhuis, Marten; van der Klei, Ida J.

    2009-01-01

    This study aimed at developing an alternative host for the production of penicillin ( PEN). As yet, the industrial production of this beta(-)lactam antibiotic is confined to the filamentous fungus Penicillium chrysogenum. As such, the yeast Hansenula polymorpha, a recognized producer of pharmaceutic

  7. Arachidonic acid metabolites in pathogenic yeasts

    Directory of Open Access Journals (Sweden)

    Ells Ruan

    2012-08-01

    Full Text Available Abstract Although most of what is known about the biology and function of arachidonic acid metabolites comes from the study of mammalian biology, these compounds can also be produced by lower eukaryotes, including yeasts and other fungi. It is also in this group of organisms that the least is known about the metabolic pathways leading to the production of these compounds as well as the functions of these compounds in the biology of fungi and yeasts. This review will deal with the discovery of oxylipins from polyunsaturated fatty acids, and more specifically the arachidonic acid derived eicosanoids, such as 3-hydroxy eicosatetraenoic acid, prostaglandin F2α and prostaglandin E2, in yeasts starting in the early 1990s. This review will also focus on what is known about the metabolic pathways and/or proteins involved in the production of these compounds in pathogenic yeasts. The possible roles of these compounds in the biology, including the pathology, of these organisms will be discussed.

  8. Effect of yeast storage temperature and flour composition on fermentative activities of baker's yeast

    Directory of Open Access Journals (Sweden)

    Pejin Dušanka J.

    2009-01-01

    Full Text Available Baker's yeast is a set of living cells of Saccharomyces cerevisiae. It contains around 70-72% of water, 42-45% of proteins, around 40% of carbohydrates, around 7.5% of lipids (based on dry matter, and vitamin B-complex. On the basis of yeast cell analysis it can be concluded that yeast is a complex biological system which changes in time. The intensity of the changes depends on temperature. Yeast sample was stored at 4°C i 24°C for 12 days. During storage at 4°C, the content of total carbohydrates decreased from 48.81% to 37.50% (dry matter, whereas carbohydrate loss ranged from 40.81% to 29.28% at 24°C. The content of trehalose was 12.33% in the yeast sample stored at 4°C and 0.24% at 24°C. Loss of fermentative activity was 81.76% in the sample stored at 24°C for 12 days. The composition of five samples of 1st category flour was investigated. It was found that flours containing more reducing sugars and maltose enable higher fermentation activities. The flours with higher ash content (in the range 0.5-0.94% had higher contents of phytic acid. Higher ash and phytic contents in flour increased the yeast fermentative efficiency. In bakery industry, a range of ingredients has been applied to improve the product's quality such as surface active substances (emulsifiers, enzymes, sugars and fats. In the paper, the effect of some ingredients added to dough (margarine, saccharose, sodium chloride and malted barley on the yeast fermentative activity was studied. The mentioned ingredients were added to dough at different doses: 0.5, 1.0, 1.5 and 2.0%, flour basis. It was found that the investigated ingredients affected the fermentative activity of yeast and improved the bread quality.

  9. Yeast Interacting Proteins Database: YMR294W, YLL049W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available YMR294W JNM1 Component of the yeast dynactin complex, consisting of Nip100p, Jnm1p,... for nuclear migration; null mutant shows a reduced affinity for the alcian blue dye...M1 Bait description Component of the yeast dynactin complex, consisting of Nip100...nknown function; required for nuclear migration; null mutant shows a reduced affinity for the alcian blue dye

  10. Exploring Catalase and Invertase Activity Using Sodium Alginate-Encapsulated Yeast (Yeast Spheres

    Directory of Open Access Journals (Sweden)

    Pamela J. Bryer

    2016-12-01

    Full Text Available Finding the right enzyme experiment can be problematic, depending what one is trying to show, what supplies and equipment are available, and the time one can devote to the topic.  I’ve developed simple and inexpensive labs for looking at catalase and invertase activity using yeast encapsulated in sodium alginate.  Single-celled yeast, Saccharomyces cerevisiae, are encapsulated in sodium alginate, a readily available extract from brown algae that, when it comes in contact with calcium chloride (CaCl2, forms a sphere or “bead.”  These spheres may then be put into a solution containing substrate to test for enzyme activity.  The spheres are easy to manipulate, one doesn’t have the variability and mess of a yeast solution, and since there are no cells in solution, there is nothing to interfere with the various assay methods one might want to use to test for product.  The graduated cylinder method for testing catalase activity introduced here is especially good for collecting large amounts of data that enable students to use statistics and, unlike similar yeast catalase experiments using paper disks and a yeast solution, the yeast spheres are easy to manipulate and there is very little variability.  I have used this procedure with students in class and with teachers in workshops with positive results and comments.

  11. Evolutionary constraints on yeast protein size

    Directory of Open Access Journals (Sweden)

    Blomberg Anders

    2006-08-01

    Full Text Available Abstract Background Despite a strong evolutionary pressure to reduce genome size, proteins vary in length over a surprisingly wide range also in very compact genomes. Here we investigated the evolutionary forces that act on protein size in the yeast Saccharomyces cerevisiae utilizing a system-wide bioinformatics approach. Data on yeast protein size was compared to global experimental data on protein expression, phenotypic pleiotropy, protein-protein interactions, protein evolutionary rate and biochemical classification. Results Comparing the experimentally determined abundance of individual proteins, highly expressed proteins were found to be consistently smaller than lowly expressed proteins, in accordance with the biosynthetic cost minimization hypothesis. Yeast proteins able to maintain a high expression level despite a large size tended to belong to a very distinct set of protein families, notably nuclear transport and translation initiation/elongation. Large proteins have significantly more protein-protein interactions than small proteins, suggesting that a requirement for multiple interaction domains may constitute a positive selective pressure for large protein size in yeast. The higher frequency of protein-protein interactions in large proteins was not accompanied by a higher phenotypic pleiotropy. Hence, the increase in interactions may not reflect an increase in function differentiation. Proteins of different sizes also evolved at similar rates. Finally, whereas the biological process involved was found to have little influence on protein size the biochemical activity exerted by the protein represented a dominant factor. More than one third of all biochemical activity classes were enriched in one or more size intervals. Conclusion In yeast, there is an inverse relationship between protein size and protein expression such that highly expressed proteins tend to be of smaller size. Also, protein size is moderately affected by protein

  12. Evaluation of fungichrom 1: A new yeast identification system

    Directory of Open Access Journals (Sweden)

    Umabala P

    2002-01-01

    Full Text Available Advances in anti-fungal therapy necessitate the need for accurate identification of fungi especially yeasts to their species level for more effective management. Unlike the time consuming conventional methods of yeast identification using fermentation and assimilation patterns of various carbohydrates, the new commercialized yeast identification systems are simpler, rapid and are particularly easy to interpret. In our study, a new colorimetric yeast identification system-Fungichrom 1(International microbio, Signes, France was evaluated against the conventional method to identify 50 clinical isolates of yeasts belonging to the genera -Candida, Cryptococcus, Geotrichum. 96% agreement was found between the two methods.

  13. Evaluation of Fungichrom 1: a new yeast identification system.

    Science.gov (United States)

    Umabala, P; Satheeshkumar, T; Lakshmi, V

    2002-01-01

    Advances in anti-fungal therapy necessitate the need for accurate identification of fungi especially yeasts to their species level for more effective management. Unlike the time consuming conventional methods of yeast identification using fermentation and assimilation patterns of various carbohydrates, the new commercialized yeast identification systems are simpler, rapid and are particularly easy to interpret. In our study, a new colorimetric yeast identification system-Fungichrom 1(International microbio, Signes, France) was evaluated against the conventional method to identify 50 clinical isolates of yeasts belonging to the genera -Candida, Cryptococcus, Geotrichum. 96% agreement was found between the two methods.

  14. Seed yeast cultivation for salad oil manufacturing wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The mixture of five yeast strains obtained from soil could remove about 85% TOC of oil-rich wastewater in batch test.While the highest MLSS was obtained at an N:C of 1:5, the oil removal decreased with the increase of N:C during yeast sludge cultivation. Ammonium chloride was the best nitrogen source for yeast cultivation from the viewpoint of yeast growth and oil utilization. An ammonia concentration of over 1300 mg l-1 led to mass death of yeast at a pH of 5. The ammonia concentration should be controlled at a level of 1000 mg l-1 or lower.

  15. Inventions on baker's yeast strains and specialty ingredients.

    Science.gov (United States)

    Gélinas, Pierre

    2009-06-01

    Baker's yeast is one of the oldest food microbial starters. Between 1927 and 2008, 165 inventions on more than 337 baker's yeast strains were patented. The first generation of patented yeast strains claimed improved biomass yield at the yeast plant, higher gassing power in dough or better survival to drying to prepare active dry baker's yeast. Especially between 1980 and 1995, a major interest was given to strains for multiple bakery applications such as dough with variable sugar content and stored at refrigeration (cold) or freezing temperatures. During the same period, genetically engineered yeast strains became very popular but did not find applications in the baking industry. Since year 2000, patented baker's yeast strains claimed aroma, anti-moulding or nutritive properties to better meet the needs of the baking industry. In addition to patents on yeast strains, 47 patents were issued on baker's yeast specialty ingredients for niche markets. This review shows that patents on baker's yeast with improved characteristics such as aromatic or nutritive properties have regularly been issued since the 1920's. Overall, it also confirms recent interest for a very wide range of tailored-made yeast-based ingredients for bakery applications.

  16. Ability of RapID Yeast Plus System to identify 304 clinically significant yeasts within 5 hours.

    OpenAIRE

    Kitch, T T; Jacobs, M R; McGinnis, M R; Appelbaum, P C

    1996-01-01

    The RapID Yeast Plus System (Innovative Diagnostic Systems, Norcross, Ga.) is a qualitative micromethod that uses conventional and chromogenic substrates for the identification of medically important yeasts. The ability of the RapID Yeast Plus system to accurately identify 304 clinical yeast isolates within 5 h was evaluated. The RapID Yeast Plus method correctly identified 286 (94.1%) of strains to the species level without the need for additional tests. A further 12 strains (3.9%) were clas...

  17. Application of hybrid yeasts for molasses fermentation during the production of alcohol and bakers' yeast

    Energy Technology Data Exchange (ETDEWEB)

    Raev, Z.A.; Kovalenko, A.D.; Korobkova, L.A.; Sadovnikova, T.A.; Bespalaya, M.K.

    1973-01-01

    Various hybrids of brewers yeasts were studied and their technological properties established. It was shown that hybrid 75 was suitable for increasing alcohol yields from molasses. Hybrid 112 was suitable for increasing the maltase activity of bakers' yeast. Efficient exploitation of the above properties of yeast hybrids may be achieved in a 2 stage molasses fermentation process developed at the Ukrainian Res. Inst. of Distillery Ind. The method is based on 2-stage yeast addition: strain B yeasts in the 1st stage and an appropriate hybrid in the second.

  18. The role of indigenous yeasts in traditional Irish cider fermentations.

    Science.gov (United States)

    Morrissey, W F; Davenport, B; Querol, A; Dobson, A D W

    2004-01-01

    To study the role of the indigenous yeast flora in traditional Irish cider fermentations. Wallerstein laboratory nutrient agar supplemented with biotin, ferric ammonium citrate, calcium carbonate and ethanol was employed together with PCR-restriction fragment length polymorphism analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene in the identification of indigenous yeasts at the species level, from traditional Irish cider fermentations. By combining the molecular approach and the presumptive media it was possible to distinguish between a large number of yeast species, and to track them within cider fermentations. The Irish cider fermentation process can be divided into three sequential phases based on the predominant yeast type present. Kloeckera/Hanseniaspora uvarum type yeasts predominate in the initial 'fruit yeast phase'. Thereafter Saccharomyces cerevisiae type yeast dominate in the 'fermentation phase', where the alcoholic fermentation takes place. Finally the 'maturation phase' which follows, is dominated by Dekkera and Brettanomyces type yeasts. H. uvarum type yeast were found to have originated from the fruit. Brettanomyces type yeast could be traced back to the press house, and also to the fruit. The press house was identified as having high levels of S. cerevisiae type yeast. A strong link was noted between the temperature profile of the cider fermentations, which ranged from 22 to 35 degrees C and the yeast strain population dynamics. Many different indigenous yeast species were identified. The mycology of Irish cider fermentations appears to be very similar to that which has previously been reported in the wine industry. This study has allowed us to gain a better understanding of the role of indigenous yeast species in 'Natural' Irish cider fermentations. Copyright 2004 The Society for Applied Microbiology

  19. Yeast Biodiversity from DOQ Priorat Uninoculated Fermentations.

    Science.gov (United States)

    Padilla, Beatriz; García-Fernández, David; González, Beatriz; Izidoro, Iara; Esteve-Zarzoso, Braulio; Beltran, Gemma; Mas, Albert

    2016-01-01

    Climate, soil, and grape varieties are the primary characteristics of terroir and lead to the definition of various appellations of origin. However, the microbiota associated with grapes are also affected by these conditions and can leave a footprint in a wine that will be part of the characteristics of terroir. Thus, a description of the yeast microbiota within a vineyard is of interest not only to provide a better understanding of the winemaking process, but also to understand the source of microorganisms that maintain a microbial footprint in wine from the examined vineyard. In this study, two typical grape varieties, Grenache and Carignan, have been sampled from four different vineyards in the DOQ Priorat winegrowing region. Afterward, eight spontaneous alcoholic fermentations containing only grapes from one sampling point and of one variety were conducted at laboratory scale. The fermentation kinetics and yeast population dynamics within each fermentation experiment were evaluated. Yeast identification was performed by RFLP-PCR of the 5.8S-ITS region and by sequencing D1/D2 of the 26S rRNA gene of the isolates. The fermentation kinetics did not indicate clear differences between the two varieties of grapes or among vineyards. Approximately 1,400 isolates were identified, exhibiting high species richness in some fermentations. Of all the isolates studied, approximately 60% belong to the genus Hanseniaspora, 16% to Saccharomyces, and 11% to Candida. Other minor genera, such as Hansenula, Issatchenkia, Kluyveromyces, Saccharomycodes, and Zygosaccharomyces, were also found. The distribution of the identified yeast throughout the fermentation process was studied, and Saccharomyces cerevisiae was found to be present mainly at the end of the fermentation process, while Aureobasidium pullulans was isolated primarily during the first days of fermentation in three of the eight spontaneous fermentations. This work highlights the complexity and diversity of the vineyard

  20. Genetics and breeding of brewers yeast

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson-Tillgren, T.; Gjermansen, C.; Petersen, J.G.L.; Holmberg, S.; Kielland-Brandt, M.C.

    1984-01-01

    Yeasts, used for beer production, can be divided into two groups, top fermenters and bottom fermenters and Saccharomyces carlsbergensis has been chosen as the name for the bottom fermenting yeasts which are used in lager beer production. The key for the analysis of the chromosomes of Saccharomyces carlsbergensis was provided by the discovery that single chromosomes of meiotic segregants of these strains can be transferred to genetically marked Saccharomyces cerevisiae strains and subsequently analyzed by tetrad analysis and molecular hybridization. It is proposed that Saccharomyces carlsbergensis is composed of two rather divergent genotypes. Breeding can be accomplished by cross breeding and mutagenesis and possibly by introducing in vitro modified cloned genes into meiotic segregants of Saccharomyces carlsbergensis.

  1. Microcompartments within the yeast plasma membrane.

    Science.gov (United States)

    Merzendorfer, Hans; Heinisch, Jürgen J

    2013-02-01

    Recent research in cell biology makes it increasingly clear that the classical concept of compartmentation of eukaryotic cells into different organelles performing distinct functions has to be extended by microcompartmentation, i.e., the dynamic interaction of proteins, sugars, and lipids at a suborganellar level, which contributes significantly to a proper physiology. As different membrane compartments (MCs) have been described in the yeast plasma membrane, such as those defined by Can1 and Pma1 (MCCs and MCPs), Saccharomyces cerevisiae can serve as a model organism, which is amenable to genetic, biochemical, and microscopic studies. In this review, we compare the specialized microcompartment of the yeast bud neck with other plasma membrane substructures, focusing on eisosomes, cell wall integrity-sensing units, and chitin-synthesizing complexes. Together, they ensure a proper cell division at the end of mitosis, an intricately regulated process, which is essential for the survival and proliferation not only of fungal, but of all eukaryotic cells.

  2. FYPO: the fission yeast phenotype ontology.

    Science.gov (United States)

    Harris, Midori A; Lock, Antonia; Bähler, Jürg; Oliver, Stephen G; Wood, Valerie

    2013-07-01

    To provide consistent computable descriptions of phenotype data, PomBase is developing a formal ontology of phenotypes observed in fission yeast. The fission yeast phenotype ontology (FYPO) is a modular ontology that uses several existing ontologies from the open biological and biomedical ontologies (OBO) collection as building blocks, including the phenotypic quality ontology PATO, the Gene Ontology and Chemical Entities of Biological Interest. Modular ontology development facilitates partially automated effective organization of detailed phenotype descriptions with complex relationships to each other and to underlying biological phenomena. As a result, FYPO supports sophisticated querying, computational analysis and comparison between different experiments and even between species. FYPO releases are available from the Subversion repository at the PomBase SourceForge project page (https://sourceforge.net/p/pombase/code/HEAD/tree/phenotype_ontology/). The current version of FYPO is also available on the OBO Foundry Web site (http://obofoundry.org/).

  3. Structural Studies of the Yeast Mitochondrial Degradosome

    DEFF Research Database (Denmark)

    Feddersen, Ane; Jonstrup, Anette Thyssen; Brodersen, Ditlev Egeskov

    The yeast mitochondrial degradosome/exosome (mtExo) is responsible for most RNA turnover in mitochondria and has been proposed to form a central part of a mitochondrial RNA surveillance system responsible for degradation of aberrant and unprocessed RNA ([1], [2]). In contrast to the cytoplasmic...... and nuclear exosome complexes, which consist of 10-12 different nuclease subunits, the mitochondrial degradosome is composed of only two large subunits - an RNase (Dss1p) and a helicase (Suv3p), belonging the Ski2 class of DExH box RNA helicases. Both subunits are encoded on the yeast nuclear genome...... and imported to the mitochondrial matrix posttranslationally. In an effort to understand the complex mechanisms underlying control of RNA turnover and surveillance in eukaryotic organisms, we are studying the structure of the mitochondrial degradosome as a model system for the more complex exosomes. Dss1p...

  4. De novo biosynthesis of vanillin in fission yeast (Schizosaccharomyces pombe) and baker's yeast (Saccharomyces cerevisiae).

    Science.gov (United States)

    Hansen, Esben H; Møller, Birger Lindberg; Kock, Gertrud R; Bünner, Camilla M; Kristensen, Charlotte; Jensen, Ole R; Okkels, Finn T; Olsen, Carl E; Motawia, Mohammed S; Hansen, Jørgen

    2009-05-01

    Vanillin is one of the world's most important flavor compounds, with a global market of 180 million dollars. Natural vanillin is derived from the cured seed pods of the vanilla orchid (Vanilla planifolia), but most of the world's vanillin is synthesized from petrochemicals or wood pulp lignins. We have established a true de novo biosynthetic pathway for vanillin production from glucose in Schizosaccharomyces pombe, also known as fission yeast or African beer yeast, as well as in baker's yeast, Saccharomyces cerevisiae. Productivities were 65 and 45 mg/liter, after introduction of three and four heterologous genes, respectively. The engineered pathways involve incorporation of 3-dehydroshikimate dehydratase from the dung mold Podospora pauciseta, an aromatic carboxylic acid reductase (ACAR) from a bacterium of the Nocardia genus, and an O-methyltransferase from Homo sapiens. In S. cerevisiae, the ACAR enzyme required activation by phosphopantetheinylation, and this was achieved by coexpression of a Corynebacterium glutamicum phosphopantetheinyl transferase. Prevention of reduction of vanillin to vanillyl alcohol was achieved by knockout of the host alcohol dehydrogenase ADH6. In S. pombe, the biosynthesis was further improved by introduction of an Arabidopsis thaliana family 1 UDP-glycosyltransferase, converting vanillin into vanillin beta-D-glucoside, which is not toxic to the yeast cells and thus may be accumulated in larger amounts. These de novo pathways represent the first examples of one-cell microbial generation of these valuable compounds from glucose. S. pombe yeast has not previously been metabolically engineered to produce any valuable, industrially scalable, white biotech commodity.

  5. Effect of Yeast : Saccharomyces cerevisiae and Marine Yeast as probiotic supplement on performance of poultry

    Directory of Open Access Journals (Sweden)

    I Putu Kompiang

    2002-03-01

    Full Text Available An experiment had been conducted to evaluate the effect of marine yeast and Saccharomyces cerevisiae (Sc as probiotic supplement on poultry performance. Marine yeast isolated from rotten sea-weed and commercial Saccharomyces cerevisiae were used. Evaluation was conducted by comparing performance of broiler chicken supplemented with marine yeast or Sc, which were given through drinking water (5 ml/l to negative control (feed without antibiotic growth promotor/GPA, positive control (feed with GPA, and reference commercial probiotic. Forty DOC broiler birds were used for each treatment, divided into 4 replicates (10 birds/replicate and raised in wire cages for 5 weeks. Body weight and feed consumption were measured weekly and mortality was recorded during the trial. The results showed that there were no significant difference on the birds performance among marine yeast, Sc, positive control and probiotic reference control treatments. However their effects on bird performance were better (P<0.05 than treatment of negative control. It is concluded that marine yeast or Saccharomyces cerevisiae could replace the function of antibiotic as a growth promotant.

  6. Biotechnology of non-Saccharomyces yeasts-the basidiomycetes.

    Science.gov (United States)

    Johnson, Eric A

    2013-09-01

    Yeasts are the major producer of biotechnology products worldwide, exceeding production in capacity and economic revenues of other groups of industrial microorganisms. Yeasts have wide-ranging fundamental and industrial importance in scientific, food, medical, and agricultural disciplines (Fig. 1). Saccharomyces is the most important genus of yeast from fundamental and applied perspectives and has been expansively studied. Non-Saccharomyces yeasts (non-conventional yeasts) including members of the Ascomycetes and Basidiomycetes also have substantial current utility and potential applicability in biotechnology. In an earlier mini-review, "Biotechnology of non-Saccharomyces yeasts-the ascomycetes" (Johnson Appl Microb Biotechnol 97: 503-517, 2013), the extensive biotechnological utility and potential of ascomycetous yeasts are described. Ascomycetous yeasts are particularly important in food and ethanol formation, production of single-cell protein, feeds and fodder, heterologous production of proteins and enzymes, and as model and fundamental organisms for the delineation of genes and their function in mammalian and human metabolism and disease processes. In contrast, the roles of basidiomycetous yeasts in biotechnology have mainly been evaluated only in the past few decades and compared to the ascomycetous yeasts and currently have limited industrial utility. From a biotechnology perspective, the basidiomycetous yeasts are known mainly for the production of enzymes used in pharmaceutical and chemical synthesis, for production of certain classes of primary and secondary metabolites such as terpenoids and carotenoids, for aerobic catabolism of complex carbon sources, and for bioremediation of environmental pollutants and xenotoxicants. Notwithstanding, the basidiomycetous yeasts appear to have considerable potential in biotechnology owing to their catabolic utilities, formation of enzymes acting on recalcitrant substrates, and through the production of unique primary

  7. Physiology of yeasts in alcoholic fermentation processes

    OpenAIRE

    Guimarães, Pedro M. R.

    2008-01-01

    Tese de Doutoramento em Engenharia Química e Biológica This thesis is focused on physiological aspects of the yeasts used in two alcoholic fermentation processes: primary brewing fermentation and fermentation of lactose (particularly lactose derived from cheese whey) to ethanol by recombinant Saccharomyces cerevisiae flocculent strains. The brewing fermentation is probably the most extensively studied alcoholic fermentation process. Nevertheless, developments in brewing tech...

  8. Taxonomy Icon Data: fission yeast [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available fission yeast Schizosaccharomyces pombe Schizosaccharomyces_pombe_L.png Schizosaccharomy...ces_pombe_NL.png Schizosaccharomyces_pombe_S.png Schizosaccharomyces_pombe_NS.png http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Schizosaccharomyces+pombe&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomy...ces+pombe&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomy...ces+pombe&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Schizosaccharomyces+pombe&t=NS

  9. Multipurpose Transposon-Insertion Libraries in Yeast.

    Science.gov (United States)

    Kumar, Anuj

    2016-06-01

    Libraries of transposon-insertion alleles constitute powerful and versatile tools for large-scale analysis of yeast gene function. Transposon-insertion libraries are constructed most simply through mutagenesis of a plasmid-based genomic DNA library; modification of the mutagenizing transposon by incorporation of yeast selectable markers, recombination sites, and an epitope tag enables the application of insertion alleles for phenotypic screening and protein localization. In particular, yeast genomic DNA libraries have been mutagenized with modified bacterial transposons carrying the URA3 marker, lox recombination sites, and sequence encoding multiple copies of the hemagglutinin (HA) epitope. Mutagenesis with these transposons has yielded a large resource of insertion alleles affecting nearly 4000 yeast genes in total. Through well-established protocols, these insertion libraries can be introduced into the desired strain backgrounds and the resulting insertional mutants can be screened or systematically analyzed. Relative to alternative methods of UV irradiation or chemical mutagenesis, transposon-insertion alleles can be easily identified by PCR-based approaches or high-throughput sequencing. Transposon-insertion libraries also provide a cost-effective alternative to targeted deletion approaches, although, in contrast to start-codon to stop-codon deletions, insertion alleles might not represent true null-mutants. For protein-localization studies, transposon-insertion alleles can provide encoded epitope tags in-frame with internal codons; in many cases, these transposon-encoded epitope tags can provide a more accurate localization for proteins in which terminal sequences are crucial for intracellular targeting. Thus, overall, transposon-insertion libraries can be used quickly and economically and have a particular utility in screening for desired phenotypes and localization patterns in nonstandard genetic backgrounds.

  10. Yeast Biodiversity from DOQ Priorat Uninoculated Fermentations

    OpenAIRE

    Padilla, Beatriz; García-Fernández, David; González, Beatriz; Izidoro, Iara; Esteve-Zarzoso, Braulio; Beltran, Gemma; Mas, Albert

    2016-01-01

    Climate, soil, and grape varieties are the primary characteristics of terroir and lead to the definition of various appellations of origin. However, the microbiota associated with grapes are also affected by these conditions and can leave a footprint in a wine that will be part of the characteristics of terroir. Thus, a description of the yeast microbiota within a vineyard is of interest not only to provide a better understanding of the winemaking process, but also to understand the source of...

  11. An engineered yeast efficiently secreting penicillin.

    Directory of Open Access Journals (Sweden)

    Loknath Gidijala

    Full Text Available This study aimed at developing an alternative host for the production of penicillin (PEN. As yet, the industrial production of this beta-lactam antibiotic is confined to the filamentous fungus Penicillium chrysogenum. As such, the yeast Hansenula polymorpha, a recognized producer of pharmaceuticals, represents an attractive alternative. Introduction of the P. chrysogenum gene encoding the non-ribosomal peptide synthetase (NRPS delta-(L-alpha-aminoadipyl-L-cysteinyl-D-valine synthetase (ACVS in H. polymorpha, resulted in the production of active ACVS enzyme, when co-expressed with the Bacillus subtilis sfp gene encoding a phosphopantetheinyl transferase that activated ACVS. This represents the first example of the functional expression of a non-ribosomal peptide synthetase in yeast. Co-expression with the P. chrysogenum genes encoding the cytosolic enzyme isopenicillin N synthase as well as the two peroxisomal enzymes isopenicillin N acyl transferase (IAT and phenylacetyl CoA ligase (PCL resulted in production of biologically active PEN, which was efficiently secreted. The amount of secreted PEN was similar to that produced by the original P. chrysogenum NRRL1951 strain (approx. 1 mg/L. PEN production was decreased over two-fold in a yeast strain lacking peroxisomes, indicating that the peroxisomal localization of IAT and PCL is important for efficient PEN production. The breakthroughs of this work enable exploration of new yeast-based cell factories for the production of (novel beta-lactam antibiotics as well as other natural and semi-synthetic peptides (e.g. immunosuppressive and cytostatic agents, whose production involves NRPS's.

  12. An engineered yeast efficiently secreting penicillin.

    Science.gov (United States)

    Gidijala, Loknath; Kiel, Jan A K W; Douma, Rutger D; Seifar, Reza M; van Gulik, Walter M; Bovenberg, Roel A L; Veenhuis, Marten; van der Klei, Ida J

    2009-12-15

    This study aimed at developing an alternative host for the production of penicillin (PEN). As yet, the industrial production of this beta-lactam antibiotic is confined to the filamentous fungus Penicillium chrysogenum. As such, the yeast Hansenula polymorpha, a recognized producer of pharmaceuticals, represents an attractive alternative. Introduction of the P. chrysogenum gene encoding the non-ribosomal peptide synthetase (NRPS) delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS) in H. polymorpha, resulted in the production of active ACVS enzyme, when co-expressed with the Bacillus subtilis sfp gene encoding a phosphopantetheinyl transferase that activated ACVS. This represents the first example of the functional expression of a non-ribosomal peptide synthetase in yeast. Co-expression with the P. chrysogenum genes encoding the cytosolic enzyme isopenicillin N synthase as well as the two peroxisomal enzymes isopenicillin N acyl transferase (IAT) and phenylacetyl CoA ligase (PCL) resulted in production of biologically active PEN, which was efficiently secreted. The amount of secreted PEN was similar to that produced by the original P. chrysogenum NRRL1951 strain (approx. 1 mg/L). PEN production was decreased over two-fold in a yeast strain lacking peroxisomes, indicating that the peroxisomal localization of IAT and PCL is important for efficient PEN production. The breakthroughs of this work enable exploration of new yeast-based cell factories for the production of (novel) beta-lactam antibiotics as well as other natural and semi-synthetic peptides (e.g. immunosuppressive and cytostatic agents), whose production involves NRPS's.

  13. Telomere behavior in a hybrid yeast

    Institute of Scientific and Technical Information of China (English)

    Ona C Martin; Christopher G De Sevo; Benjamin Z Guo; Douglas E Koshland; Maiterya J Dunham; Yixian Zheng

    2009-01-01

    @@ Dear Editor, Telomeres and the protein/RNA complexes involved in maintaining them are rapidly evolving systems across eukaryotes.Using two Saccharomyces species, among S.cerevisiae and S.bayanus, we provide evidence that the telomere systems of these two closely related yeasts have evolved significantly apart and that the gene in one spe-cies cannot maintain the set-point of telomere length of the other soecies in the hybrid.

  14. Secretion of invertase in mitotic yeast cells.

    OpenAIRE

    Makarow, M

    1988-01-01

    In mammalian cells intracellular transport is inhibited during mitosis. Here we show that in the yeast Saccharomyces cerevisiae secretion continues uninterrupted during mitosis. S. cerevisiae cells were arrested in mitosis by treating wild-type cells with the microtubule-inhibitor nocodazole, or by incubating a temperature-sensitive cell division cycle mutant (cdc16) at the restrictive temperature. Secretion of invertase into the periplasmic space was equally efficient in mitotic and in unsyn...

  15. Strategies for identifying new prions in yeast

    OpenAIRE

    MacLea, Kyle S.; Ross, Eric D.

    2011-01-01

    The unexpected discovery of two prions, [URE3] and [PSI+], in Saccharomyces cerevisiae led to questions about how many other proteins could undergo similar prion-based structural conversions. However, [URE3] and [PSI+] were discovered by serendipity in genetic screens. Cataloging the full range of prions in yeast or in other organisms will therefore require more systematic search methods. Taking advantage of some of the unique features of prions, various researchers have developed bioinformat...

  16. Dissection and design of yeast prions.

    OpenAIRE

    Osherovich, Lev Z.; Cox, Brian S; Tuite, Mick F; Weissman, Jonathan S.

    2004-01-01

    Many proteins can misfold into beta-sheet-rich, self-seeding polymers (amyloids). Prions are exceptional among such aggregates in that they are also infectious. In fungi, prions are not pathogenic but rather act as epigenetic regulators of cell physiology, providing a powerful model for studying the mechanism of prion replication. We used prion-forming domains from two budding yeast proteins (Sup35p and New1p) to examine the requirements for prion formation and inheritance. In both proteins, ...

  17. Yeasts found in vineyards and wineries.

    Science.gov (United States)

    Varela, Cristian; Borneman, Anthony R

    2017-03-01

    Wine is a complex beverage, comprising thousands of metabolites that are produced through the action of a plethora of yeasts and bacteria during fermentation of grape must. These microbial communities originate in the vineyard and the winery and reflect the influence of several factors including grape variety, geographical location, climate, vineyard spraying, technological practices, processing stage and season (pre-harvest, harvest, post-harvest). Vineyard and winery microbial communities have the potential to participate during fermentation and influence wine flavour and aroma. Therefore, there is an enormous interest in isolating and characterising these communities, particularly non-Saccharomyces yeast species to increase wine flavour diversity, while also exploting regional signature microbial populations to enhance regionality. In this review we describe the role and relevance of the main non-Saccharomyces yeast species found in vineyards and wineries. This includes the latest reports covering the application of these species for winemaking; and the biotechnological characteristics and potential applications of non-Saccharomyces species in other areas. In particular, we focus attention on the species for which molecular and genomic tools and resources are available for study. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Role of yeasts in table olive production.

    Science.gov (United States)

    Arroyo-López, F N; Querol, A; Bautista-Gallego, J; Garrido-Fernández, A

    2008-12-10

    Table olives are a traditional fermented vegetable of the Mediterranean countries, but their production and consumption are now spread all around the world. Yeasts can play a double role in this food. They are present throughout the fermentative process and it is generally accepted that they can produce compounds with important organoleptic attributes determining the quality and flavour of the final product. However, yeasts can also be spoilage microorganisms in olive fermentation/storage and packing causing gas pockets, swollen containers, cloudy brines and off-flavours and off-odours. Candida boidinii, Debaryomyces hansenii, Pichia anomala, P. membranifaciens, Rhodotorula glutinis and Saccharomyces cerevisiae are species isolated with a high frequency from olive processes. Scarce information is still available about the ecology, biochemistry and molecular biology of these important microorganisms in table olives. A wider knowledge about these aspects could facilitate the possible application of yeasts as a starter culture, due to their ability to produce aromatic compounds, antioxidants, enzymes, and improve the growth of lactic acid bacteria.

  19. How do yeast sense mitochondrial dysfunction?

    Directory of Open Access Journals (Sweden)

    Dmitry A. Knorre

    2016-09-01

    Full Text Available Apart from energy transformation, mitochondria play important signaling roles. In yeast, mitochondrial signaling relies on several molecular cascades. However, it is not clear how a cell detects a particular mitochondrial malfunction. The problem is that there are many possible manifestations of mitochondrial dysfunction. For example, exposure to the specific antibiotics can either decrease (inhibitors of respiratory chain or increase (inhibitors of ATP-synthase mitochondrial transmembrane potential. Moreover, even in the absence of the dysfunctions, a cell needs feedback from mitochondria to coordinate mitochondrial biogenesis and/or removal by mitophagy during the division cycle. To cope with the complexity, only a limited set of compounds is monitored by yeast cells to estimate mitochondrial functionality. The known examples of such compounds are ATP, reactive oxygen species, intermediates of amino acids synthesis, short peptides, Fe-S clusters and heme, and also the precursor proteins which fail to be imported by mitochondria. On one hand, the levels of these molecules depend not only on mitochondria. On the other hand, these substances are recognized by the cytosolic sensors which transmit the signals to the nucleus leading to general, as opposed to mitochondria-specific, transcriptional response. Therefore, we argue that both ways of mitochondria-to-nucleus communication in yeast are mostly (if not completely unspecific, are mediated by the cytosolic signaling machinery and strongly depend on cellular metabolic state.

  20. Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines.

    Science.gov (United States)

    Roohvand, Farzin; Shokri, Mehdi; Abdollahpour-Alitappeh, Meghdad; Ehsani, Parastoo

    2017-08-01

    Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

  1. YeastMed: an XML-Based System for Biological Data Integration of Yeast

    CERN Document Server

    Briache, Abdelaali; Kerzazi, Amine; Navas-Delgado, Ismael; Montes, Jose F Aldana; Hassani, Badr D Rossi; Lairini, Khalid

    2010-01-01

    A key goal of bioinformatics is to create database systems and software platforms capable of storing and analysing large sets of biological data. Hundreds of biological databases are now available and provide access to huge amount of biological data. SGD, Yeastract, CYGD-MIPS, BioGrid and PhosphoGrid are five of the most visited databases by the yeast community. These sources provide complementary data on biological entities. Biologists are brought systematically to query these data sources in order to analyse the results of their experiments. Because of the heterogeneity of these sources, querying them separately and then manually combining the returned result is a complex and laborious task. To provide transparent and simultaneous access to these sources, we have developed a mediator-based system called YeastMed. In this paper, we present YeastMed focusing on its architecture.

  2. Taming wild yeast: potential of conventional and nonconventional yeasts in industrial fermentations.

    Science.gov (United States)

    Steensels, Jan; Verstrepen, Kevin J

    2014-01-01

    Yeasts are the main driving force behind several industrial food fermentation processes, including the production of beer, wine, sake, bread, and chocolate. Historically, these processes developed from uncontrolled, spontaneous fermentation reactions that rely on a complex mixture of microbes present in the environment. Because such spontaneous processes are generally inconsistent and inefficient and often lead to the formation of off-flavors, most of today's industrial production utilizes defined starter cultures, often consisting of a specific domesticated strain of Saccharomyces cerevisiae, S. bayanus, or S. pastorianus. Although this practice greatly improved process consistency, efficiency, and overall quality, it also limited the sensorial complexity of the end product. In this review, we discuss how Saccharomyces yeasts were domesticated to become the main workhorse of food fermentations, and we investigate the potential and selection of nonconventional yeasts that are often found in spontaneous fermentations, such as Brettanomyces, Hanseniaspora, and Pichia spp.

  3. Black yeast-like fungi in skin and nail

    DEFF Research Database (Denmark)

    Saunte, D M; Tarazooie, B; Arendrup, M C

    2011-01-01

    Black yeast-like fungi are rarely reported from superficial infections. We noticed a consistent prevalence of these organisms as single isolations from mycological routine specimens. To investigate the prevalence of black yeast-like fungi in skin, hair and nail specimens and to discuss...... the probability of these species to be involved in disease. Slow-growing black yeast-like fungi in routine specimens were prospectively collected and identified. A questionnaire regarding patient information was sent to physicians regarding black yeast-like fungus positive patients. A total of 20 746...... dermatological specimens were examined by culture. Black yeast-like fungi accounted for 2.2% (n = 108) of the positive cultures. Only 31.0% of the samples, culture positive for black yeast-like fungi were direct microscopy positive when compared with overall 68.8% of the culture positive specimens. The most...

  4. Yeast Genomics for Bread, Beer, Biology, Bucks and Breath

    Science.gov (United States)

    Sakharkar, Kishore R.; Sakharkar, Meena K.

    The rapid advances and scale up of projects in DNA sequencing dur ing the past two decades have produced complete genome sequences of several eukaryotic species. The versatile genetic malleability of the yeast, and the high degree of conservation between its cellular processes and those of human cells have made it a model of choice for pioneering research in molecular and cell biology. The complete sequence of yeast genome has proven to be extremely useful as a reference towards the sequences of human and for providing systems to explore key gene functions. Yeast has been a ‘legendary model’ for new technologies and gaining new biological insights into basic biological sciences and biotechnology. This chapter describes the awesome power of yeast genetics, genomics and proteomics in understanding of biological function. The applications of yeast as a screening tool to the field of drug discovery and development are highlighted and the traditional importance of yeast for bakers and brewers is discussed.

  5. Biosorption of nickel by yeasts in an osmotically unsuitable environment

    Energy Technology Data Exchange (ETDEWEB)

    Breierova, Emilia; Kovarova, Annamaria [SAS, Bratislava (Slovakia). Inst. of Chemistry; Certik, Milan [SUT, Bratislava (Slovakia). Dept. of Biochemical Technology; Gregor, Tomas [Mendel Univ. of Agriculture and Forestry, Brno (Czech Republic)

    2008-11-15

    The tolerance, sorption of nickel(II) ions, and changes in the production and composition of exopolymers of eight yeast strains grown under nickel presence with/without NaCl were studied. Strains of Pichia anomala and Candida maltosa known as the most resistant yeasts against nickel tolerated up to 3 mm Ni{sup 2+}. NaCl addition decreased both the resistance ofthe yeast strains toward nickel ions and the sorption of metal ions into cells. All yeasts absorbed nickel predominantly into exopolymers (glycoproteins) and on the surface of cells. However, while the amount of polysaccharide moieties of exoglycoproteins of most of the resistant yeasts was induced by stress conditions, the ratio polysaccharide/protein in the exopolymers remained unchanged in the sensitive species Cystofilobasidium. The exopolymer composition might play a key role in yeast adaptation to stress conditions caused by heavy metal ions. (orig.)

  6. Isolation and characterization of ethanol tolerant yeast strains

    Science.gov (United States)

    Tikka, Chiranjeevi; Osuru, Hari Prasad; Atluri, Navya; Raghavulu, Praveen Chakravarthi Veera; yellapu, Nanda Kumar; Mannur, Ismail Shaik; Prasad, Uppu Venkateswara; Aluru, Sudheer; K, Narasimha Varma; Bhaskar, Matcha

    2013-01-01

    Yeast strains are commonly associated with sugar rich environments. Various fruit samples were selected as source for isolating yeast cells. The isolated cultures were identified at Genus level by colony morphology, biochemical characteristics and cell morphological characters. An attempt has been made to check the viability of yeast cells under different concentrations of ethanol. Ethanol tolerance of each strain was studied by allowing the yeast to grow in liquid YEPD (Yeast Extract Peptone Dextrose) medium having different concentrations of ethanol. A total of fifteen yeast strains isolated from different samples were used for the study. Seven strains of Saccharomyces cerevisiae obtained from different fruit sources were screened for ethanol tolerance. The results obtained in this study show a range of tolerance levels between 7%-12% in all the stains. Further, the cluster analysis based on 22 RAPD (Random Amplified polymorphic DNA) bands revealed polymorphisms in these seven Saccharomyces strains. PMID:23750092

  7. Genetic aspects of targeted insertion mutagenesis in yeasts.

    Science.gov (United States)

    Klinner, U; Schäfer, B

    2004-05-01

    Targeted insertion mutagenesis is a main molecular tool of yeast science initially applied in Saccharomyces cerevisiae. The method was extended to fission yeast Schizosaccharomyces pombe and to "non-conventional" yeast species, which show specific properties of special interest to both basic and applied research. Consequently, the behaviour of such non-Saccharomyces yeasts is reviewed against the background of the knowledge of targeted insertion mutagenesis in S. cerevisiae. Data of homologous integration efficiencies obtained with circular, ends-in or ends-out vectors in several yeasts are compared. We follow details of targeted insertion mutagenesis in order to recognize possible rate-limiting steps. The route of the vector to the target and possible mechanisms of its integration into chromosomal genes are considered. Specific features of some yeast species are discussed. In addition, similar approaches based on homologous recombination that have been established for the mitochondrial genome of S. cerevisiae are described.

  8. Cell surface engineering of yeast for applications in white biotechnology.

    Science.gov (United States)

    Kuroda, Kouichi; Ueda, Mitsuyoshi

    2011-01-01

    Cell surface engineering is a promising strategy for the molecular breeding of whole-cell biocatalysts. By using this strategy, yeasts can be constructed by the cell surface display of functional proteins; these yeasts are referred to as arming yeasts. Because reactions using arming yeasts as whole-cell biocatalysts occur on the cell surface, materials that cannot enter the cell can be used as reaction substrates. Numerous arming yeasts have therefore been constructed for a wide range of uses such as biofuel production, synthesis of valuable chemicals, adsorption or degradation of environmental pollutants, recovery of rare metal ions, and biosensors. Here, we review the science of yeast cell surface modification as well as current applications and future opportunities.

  9. Probiotic properties of yeasts occurring in fermented food and beverages

    DEFF Research Database (Denmark)

    Jespersen, Lene

    Besides being able to improve the quality and safety of many fermented food and beverages some yeasts offer a number of probiotic traits. Especially a group of yeast referred to as "Saccharomyces boulardii", though taxonomically belonging to Saccharomyces cerevisiae, has been claimed to have...... probiotic properties. Besides, yeasts naturally occurring globally in food and beverages will have traits that might have a positive impact on human health....

  10. Mediated Electrochemical Measurements of Intracellular Catabolic Activities of Yeast Cells

    Institute of Scientific and Technical Information of China (English)

    Jin Sheng ZHAO; Zhen Yu YANG; Yao LU; Zheng Yu YANG

    2005-01-01

    Coupling with the dual mediator system menadione/ferricyanide, microelectrode voltammetric measurements were undertaken to detect the ferrocyanide accumulations arising from the mediated reduction of ferricyanide by yeast cells. The results indicate that the dual mediator system menadione/ferricyanide could be used as a probe to detect cellular catabolic activities in yeast cells and the electrochemical response has a positive relationship with the specific growth rate of yeast cells.

  11. The Yeast Deletion Collection: A Decade of Functional Genomics

    OpenAIRE

    Giaever, Guri; Nislow, Corey

    2014-01-01

    The yeast deletion collections comprise >21,000 mutant strains that carry precise start-to-stop deletions of ∼6000 open reading frames. This collection includes heterozygous and homozygous diploids, and haploids of both MAT a and MATα mating types. The yeast deletion collection, or yeast knockout (YKO) set, represents the first and only complete, systematically constructed deletion collection available for any organism. Conceived during the Saccharomyces cerevisiae sequencing project, work on...

  12. The complexity and implications of yeast prion domains

    OpenAIRE

    Du, Zhiqiang

    2011-01-01

    Prions are infectious proteins with altered conformations converted from otherwise normal host proteins. While there is only one known mammalian prion protein, PrP, a handful of prion proteins have been identified in the yeast Saccharomyces cerevisiae. Yeast prion proteins usually have a defined region called prion domain (PrD) essential for prion properties, which are typically rich in glutamine (Q) and asparagine (N). Despite sharing several common features, individual yeast PrDs are genera...

  13. A study of yeast carriage on hands of hospital personnel.

    Science.gov (United States)

    Kumar, S; Batra, R

    2000-01-01

    The present study was conducted by culture with a modified broth wash technique to examine the frequency of yeast carriage on the hands of 60 nurses and 35 nonnursing hospital employees. Seventy two percent of the nurses and 80% of the nonnurses were harbouring yeast on their hands. Candida spp. were isolated in 57% on of nurses and 34% of nonnurses. Ninety percent of nurses working in nursing home care unit (NHCU), 50% working in intensive care unit (ICU) and 75% working in outpatient department (OPD) carried yeasts on their hands. Only 80% of nonnurses staff harboured yeasts on their hands.

  14. Aboveground Deadwood Deposition Supports Development of Soil Yeasts

    Directory of Open Access Journals (Sweden)

    Thorsten Wehde

    2012-12-01

    Full Text Available Unicellular saprobic fungi (yeasts inhabit soils worldwide. Although yeast species typically occupy defined areas on the biome scale, their distribution patterns within a single type of vegetation, such as forests, are more complex. In order to understand factors that shape soil yeast communities, soils collected underneath decaying wood logs and under forest litter were analyzed. We isolated and identified molecularly a total of 25 yeast species, including three new species. Occurrence and distribution of yeasts isolated from these soils provide new insights into ecology and niche specialization of several soil-borne species. Although abundance of typical soil yeast species varied among experimental plots, the analysis of species abundance and community composition revealed a strong influence of wood log deposition and leakage of organic carbon. Unlike soils underneath logs, yeast communities in adjacent areas harbored a considerable number of transient (phylloplane-related yeasts reaching 30% of the total yeast quantity. We showed that distinguishing autochthonous community members and species transient in soils is essential to estimate appropriate effects of environmental factors on soil fungi. Furthermore, a better understanding of species niches is crucial for analyses of culture-independent data, and may hint to the discovery of unifying patterns of microbial species distribution.

  15. Identification of yeasts present in sour fermented foods and fodders.

    Science.gov (United States)

    Middelhoven, Wouter J

    2002-07-01

    This paper deals with rapid methods for identification of 50 yeast species frequently isolated from foods and fodders that underwent a lactic acid fermentation. However, many yeast species present in olive brine, alpechin, and other olive products were not treated. The methods required for identification include light microscopy, physiological growth tests (ID32C system of BioMérieux), assimilation of nitrate and of ethylamine as sole nitrogen sources, vitamin requirement, and maximum growth temperature. An identification key to treated yeast species is provided. In another table characteristics of all yeast species treated are listed.

  16. [Novel bioconversion systems using a yeast molecular display system].

    Science.gov (United States)

    Shibasaki, Seiji

    2010-11-01

    The budding yeast Saccharomyces cerevisiae has been used for the process of fermentation as well as for studies in biochemistry and molecular biology as a eukaryotic model cell or tool for the analysis of gene functions. Thus, yeast is essential in industries and researches. Yeast cells have a cell wall, which is one characteristic that helps distinguish yeast cells from other eukaryotic cells such as mammalian cells. We have developed a molecular display system using the protein of the yeast cell wall as an anchor for foreign proteins. Yeast cells have been designed for use in sensing and metal adsorption, and have been used in vaccines and for screening novel proteins. Currently, yeast is used not only as a tool for analyzing gene or protein function but also in molecular display technology. The phage display system, which is at the forefront of molecular display technologies, is a powerful tool for screening ligands bound to a target molecule and for analyzing protein-protein interactions; however, in some cases, eukaryotic proteins are not easily expressed by this system. On the other hand, yeast cells have the ability to express eukaryotic proteins and proliferate; thus, these cells display various proteins. Yeast cells are more appropriate for white biotechnology. In this review, displays of enzymes that are important in bioconversion, such as lipases and β-glucosidases, are going to be introduced.

  17. Performance of non-conventional yeasts in co-culture with brewers' yeast for steering ethanol and aroma production.

    Science.gov (United States)

    van Rijswijck, Irma M H; Wolkers-Rooijackers, Judith C M; Abee, Tjakko; Smid, Eddy J

    2017-08-18

    Increasing interest in new beer types has stimulated the search for approaches to extend the metabolic variation of brewers' yeast. Therefore, we tested two approaches using non-conventional yeast to create a beer with lower ethanol content and a complex aroma bouquet. First, the mono-culture performance was monitored of 49 wild yeast isolates of Saccharomyces cerevisiae (16 strains), Cyberlindnera fabianii (9 strains) and Pichia kudriavzevii (24 strains). Interestingly, both C. fabianii and P. kudriavzevii isolates produced relatively more esters compared with S. cerevisiae isolates, despite their limited fermentation capacity. Next, one representative strain of each species (Sc131, Cf65 and Pk129) was applied as co-culture with brewers' yeast (ratio 1:1). Co-cultures with Cf65 and Pk129 resulted in a beer with lower alcohol content (3.5, 3.8 compared with 4.2% v/v) and relatively more esters. At higher inoculum ratios of Cf65 over brewers' yeast, growth inhibition of brewers' yeast was observed, most likely caused by competition for oxygen between brewers' yeast and Cf65 resulting in a reduced level of ethanol and altered aroma profiles. With this study, we demonstrate the feasibility of using non-conventional yeast species in co-cultivation with traditional brewers' yeast to tailor aroma profiles as well as the final ethanol content of beer. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  18. Genetically modified yeast species, and fermentation processes using genetically modified yeast

    Science.gov (United States)

    Rajgarhia, Vineet; Koivuranta, Kari; Penttila, Merja; Ilmen, Marja; Suominen, Pirkko; Aristidou, Aristos; Miller, Christopher Kenneth; Olson, Stacey; Ruohonen, Laura

    2013-05-14

    Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific or specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.

  19. Genetically modified yeast species, and fermentation processes using genetically modified yeast

    Energy Technology Data Exchange (ETDEWEB)

    Rajgarhia, Vineet; Koivuranta, Kari; Penttila, Merja; Ilmen, Marja; Suominen, Pirkko; Aristidou, Aristos; Miller, Christopher Kenneth; Olson, Stacey; Ruohonen, Laura

    2016-08-09

    Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific or specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.

  20. Genetically modified yeast species, and fermentation processes using genetically modified yeast

    Energy Technology Data Exchange (ETDEWEB)

    Rajgarhia, Vineet; Koivuranta, Kari; Penttila, Merja; Ilmen, Marja; Suominen, Pirkko; Aristidou, Aristos; Miller, Christopher Kenneth; Olson, Stacey; Ruohonen, Laura

    2017-09-12

    Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific or specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.

  1. Genetically modified yeast species, and fermentation processes using genetically modified yeast

    Energy Technology Data Exchange (ETDEWEB)

    Rajgarhia, Vineet [Kingsport, TN; Koivuranta, Kari [Helsinki, FI; Penttila, Merja [Helsinki, FI; Ilmen, Marja [Helsinki, FI; Suominen, Pirkko [Maple Grove, MN; Aristidou, Aristos [Maple Grove, MN; Miller, Christopher Kenneth [Cottage Grove, MN; Olson, Stacey [St. Bonifacius, MN; Ruohonen, Laura [Helsinki, FI

    2014-01-07

    Yeast cells are transformed with an exogenous xylose isomerase gene. Additional genetic modifications enhance the ability of the transformed cells to ferment xylose to ethanol or other desired fermentation products. Those modifications include deletion of non-specific aldose reductase gene(s), deletion of xylitol dehydrogenase gene(s) and/or overexpression of xylulokinase.

  2. Yeast Interacting Proteins Database: YGR013W, YKL012W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available st specific, no metazoan counterpart Rows with this bait as bait (1) Rows with this bait as prey (0) YKL012W...U71 Bait description Component of U1 snRNP required for mRNA splicing via spliceosome; yeast specific, no metazoan counter

  3. Yeast Interacting Proteins Database: YDR311W, YMR294W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available Rows with this bait as prey (0) YMR294W JNM1 Component of the yeast dynactin complex, consisting of Nip100p...ows with this bait as prey Rows with this bait as prey (0) Prey ORF YMR294W Prey gene name JNM1 Prey description Component of the ye

  4. Yeast Interacting Proteins Database: YBR288C, YGR261C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available bait (1) Rows with this bait as prey (0) YGR261C APL6 Beta3-like subunit of the yeast AP-3 complex; functio...rey (0) Prey ORF YGR261C Prey gene name APL6 Prey description Beta3-like subunit of the ye

  5. Utilization of spent brewer’s yeast Saccharomyces cerevisiae for the production of yeast enzymatic hydrolysate

    Directory of Open Access Journals (Sweden)

    M Bayarjargal

    2014-09-01

    Full Text Available Spent brewer’s yeast (Saccharomyces cerevisiae is a rich source of protein, vitamins and widely used as a raw material for production of food supplements. The autolysis and enzymatic treatment of spent brewer’s yeast using Pancreatin (2.5% and Flavourzyme (2.5% were performed at 45 °C and 50 °C, respectively. The autolysis and hydrolysis processes were evaluated by determining a soluble solids, soluble protein concentration and α-amino nitrogen content in a reaction mixture. The yield of pancreatic digest and α-amino nitrogen content was high in comparison with autolysis and Flavourzyme treatment. The total solids recovery in dry Yeast hydrolysate was about 50%, a protein and α-amino nitrogen content was 55.9 and 4.8%, respectively. These results show the possibility of utilizing the spent brewer’s yeast as hydrolysate using hydrolytic enzymes and use it as a food supplement after biological experiments.DOI: http://dx.doi.org/10.5564/mjc.v12i0.179 Mongolian Journal of Chemistry Vol.12 2011: 88-91

  6. How does yeast respond to pressure?

    Directory of Open Access Journals (Sweden)

    P.M.B. Fernandes

    2005-08-01

    Full Text Available The brewing and baking yeast Saccharomyces cerevisiae has been used as a model for stress response studies of eukaryotic cells. In this review we focus on the effect of high hydrostatic pressure (HHP on S. cerevisiae. HHP exerts a broad effect on yeast cells characteristic of common stresses, mainly associated with protein alteration and lipid bilayer phase transition. Like most stresses, pressure induces cell cycle arrest. Below 50 MPa (500 atm yeast cell morphology is unaffected whereas above 220 MPa wild-type cells are killed. S. cerevisiae cells can acquire barotolerance if they are pretreated with a sublethal stress due to temperature, ethanol, hydrogen peroxide, or pressure. Nevertheless, pressure only leads to protection against severe stress if, after pressure pretreatment, the cells are also re-incubated at room pressure. We attribute this effect to the inhibition of the protein synthesis apparatus under HHP. The global genome expression analysis of S. cerevisiae cells submitted to HHP revealed a stress response profile. The majority of the up-regulated genes are involved in stress defense and carbohydrate metabolism while most repressed genes belong to the cell cycle progression and protein synthesis categories. However, the signaling pathway involved in the pressure response is still to be elucidated. Nitric oxide, a signaling molecule involved in the regulation of a large number of cellular functions, confers baroprotection. Furthermore, S. cerevisiae cells in the early exponential phase submitted to 50-MPa pressure show induction of the expression level of the nitric oxide synthase inducible isoform. As pressure becomes an important biotechnological tool, studies concerning this kind of stress in microorganisms are imperative.

  7. Studying Functions of All Yeast Genes Simultaneously

    Science.gov (United States)

    Stolc, Viktor; Eason, Robert G.; Poumand, Nader; Herman, Zelek S.; Davis, Ronald W.; Anthony Kevin; Jejelowo, Olufisayo

    2006-01-01

    A method of studying the functions of all the genes of a given species of microorganism simultaneously has been developed in experiments on Saccharomyces cerevisiae (commonly known as baker's or brewer's yeast). It is already known that many yeast genes perform functions similar to those of corresponding human genes; therefore, by facilitating understanding of yeast genes, the method may ultimately also contribute to the knowledge needed to treat some diseases in humans. Because of the complexity of the method and the highly specialized nature of the underlying knowledge, it is possible to give only a brief and sketchy summary here. The method involves the use of unique synthetic deoxyribonucleic acid (DNA) sequences that are denoted as DNA bar codes because of their utility as molecular labels. The method also involves the disruption of gene functions through deletion of genes. Saccharomyces cerevisiae is a particularly powerful experimental system in that multiple deletion strains easily can be pooled for parallel growth assays. Individual deletion strains recently have been created for 5,918 open reading frames, representing nearly all of the estimated 6,000 genetic loci of Saccharomyces cerevisiae. Tagging of each deletion strain with one or two unique 20-nucleotide sequences enables identification of genes affected by specific growth conditions, without prior knowledge of gene functions. Hybridization of bar-code DNA to oligonucleotide arrays can be used to measure the growth rate of each strain over several cell-division generations. The growth rate thus measured serves as an index of the fitness of the strain.

  8. Crystal structure of yeast Sco1

    Energy Technology Data Exchange (ETDEWEB)

    Abajian, Carnie; Rosenzweig, Amy C. (NWU)

    2010-03-05

    The Sco family of proteins are involved in the assembly of the dinuclear CuA site in cytochrome c oxidase (COX), the terminal enzyme in aerobic respiration. These proteins, which are found in both eukaryotes and prokaryotes, are characterized by a conserved CXXXC sequence motif that binds copper ions and that has also been proposed to perform a thiol:disulfide oxidoreductase function. The crystal structures of Saccharomyces cerevisiae apo Sco1 (apo-ySco1) and Sco1 in the presence of copper ions (Cu-ySco1) were determined to 1.8- and 2.3-{angstrom} resolutions, respectively. Yeast Sco1 exhibits a thioredoxin-like fold, similar to that observed for human Sco1 and a homolog from Bacillus subtilis. The Cu-ySco1 structure, obtained by soaking apo-ySco1 crystals in copper ions, reveals an unexpected copper-binding site involving Cys181 and Cys216, cysteine residues present in ySco1 but not in other homologs. The conserved CXXXC cysteines, Cys148 and Cys152, can undergo redox chemistry in the crystal. An essential histidine residue, His239, is located on a highly flexible loop, denoted the Sco loop, and can adopt positions proximal to both pairs of cysteines. Interactions between ySco1 and its partner proteins yeast Cox17 and yeast COX2 are likely to occur via complementary electrostatic surfaces. This high-resolution model of a eukaryotic Sco protein provides new insight into Sco copper binding and function.

  9. Specificity of transmembrane protein palmitoylation in yeast.

    Directory of Open Access Journals (Sweden)

    Ayelén González Montoro

    Full Text Available Many proteins are modified after their synthesis, by the addition of a lipid molecule to one or more cysteine residues, through a thioester bond. This modification is called S-acylation, and more commonly palmitoylation. This reaction is carried out by a family of enzymes, called palmitoyltransferases (PATs, characterized by the presence of a conserved 50- aminoacids domain called "Asp-His-His-Cys- Cysteine Rich Domain" (DHHC-CRD. There are 7 members of this family in the yeast Saccharomyces cerevisiae, and each of these proteins is thought to be responsible for the palmitoylation of a subset of substrates. Substrate specificity of PATs, however, is not yet fully understood. Several yeast PATs seem to have overlapping specificity, and it has been proposed that the machinery responsible for palmitoylating peripheral membrane proteins in mammalian cells, lacks specificity altogether.Here we investigate the specificity of transmembrane protein palmitoylation in S. cerevisiae, which is carried out predominantly by two PATs, Swf1 and Pfa4. We show that palmitoylation of transmembrane substrates requires dedicated PATs, since other yeast PATs are mostly unable to perform Swf1 or Pfa4 functions, even when overexpressed. Furthermore, we find that Swf1 is highly specific for its substrates, as it is unable to substitute for other PATs. To identify where Swf1 specificity lies, we carried out a bioinformatics survey to identify amino acids responsible for the determination of specificity or Specificity Determination Positions (SDPs and showed experimentally, that mutation of the two best SDP candidates, A145 and K148, results in complete and partial loss of function, respectively. These residues are located within the conserved catalytic DHHC domain suggesting that it could also be involved in the determination of specificity. Finally, we show that modifying the position of the cysteines in Tlg1, a Swf1 substrate, results in lack of palmitoylation, as

  10. In situ rheology of yeast biofilms.

    Science.gov (United States)

    Brugnoni, Lorena I; Tarifa, María C; Lozano, Jorge E; Genovese, Diego

    2014-01-01

    The aim of the present work was to investigate the in situ rheological behavior of yeast biofilms growing on stainless steel under static and turbulent flow. The species used (Rhodototula mucilaginosa, Candida krusei, Candida kefyr and Candida tropicalis) were isolated from a clarified apple juice industry. The flow conditions impacted biofilm composition over time, with a predominance of C. krusei under static and turbulent flow. Likewise, structural variations occurred, with a tighter appearance under dynamic flow. Under turbulent flow there was an increase of 112 μm in biofilm thickness at 11 weeks (p rheology and contribute to a thin body of knowledge about fungal biofilm formation.

  11. Taxonomy Icon Data: Budding yeast [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Budding yeast Saccharomyces cerevisiae Saccharomyces_cerevisiae_L.png Saccharomyces..._cerevisiae_NL.png Saccharomyces_cerevisiae_S.png Saccharomyces_cerevisiae_NS.png http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Saccharomyces+cerevisiae&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomy...ces+cerevisiae&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomy...ces+cerevisiae&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Saccharomyces+cerevisiae&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=216 ...

  12. Biofuels. Altered sterol composition renders yeast thermotolerant

    DEFF Research Database (Denmark)

    Caspeta, Luis; Chen, Yun; Ghiaci, Payam

    2014-01-01

    adaptive laboratory evolution to select yeast strains with improved growth and ethanol production at ≥40°C. Sequencing of the whole genome, genome-wide gene expression, and metabolic-flux analyses revealed a change in sterol composition, from ergosterol to fecosterol, caused by mutations in the C-5 sterol...... desaturase gene, and increased expression of genes involved in sterol biosynthesis. Additionally, large chromosome III rearrangements and mutations in genes associated with DNA damage and respiration were found, but contributed less to the thermotolerant phenotype....

  13. Levaduras inhibidoras de Penicillium Inhibitory Penicillium yeasts

    Directory of Open Access Journals (Sweden)

    M.R. Benítez Ahrendts

    2004-12-01

    Full Text Available El objetivo de este trabajo fue determinar la acción inhibitoria in vitro e in vivo de algunas cepas de levaduras de la zona citrícola jujeña sobre el crecimiento de los mohos patógenos post-cosecha y seleccionarlas para elaborar un producto de biocontrol. Se aislaron de frutos cítricos cepas de los mohos patógenos post-cosecha Penicillium digitatum, P. italicum,P. ulaiense, Phyllosticta sp. y Galactomyces geotrichum, así como de levaduras saprófítas de los géneros Brettanomyces, Candida, Cryptococcus, Kloeckera, Pichia y Rhodotorula. También se obtuvieron algunas levaduras de otras fuentes. Se identificaron las levaduras por las características macro y micromorfológicas y las pruebas fisiológicas. La actividad in vitro e in vivo de las diferentes cepas fue diferente según se enfrentaran a P. digitatum o P. ulaiense. Candida cantarellii y una cepa de Pichia subpelliculosa produjeron una reducción significativa del área de las lesiones provocadas por estas especies de Penicillium, y podrían ser empleadas en la formulación de un producto para biocontrol.The objective of this work was to establish the in vitro and in vivo inhibition of post-harvest pathogenic moulds by yeasts in order to make a biocontrol product. Post-harvest pathogenic moulds Penicillium digitatumP. italicum, P. ulaiense, Phyllosticta sp., Galactomyces geotrichum and yeasts belonging to genera Brettanomyces, Candida, Cryptococcus, Kloeckera,Pichia, Rhodotorula were isolated from citrus fruits. Some yeasts strains were also isolated from other sources. The yeasts were identified by their macro and micro-morphology and physiological tests. The in vitro and in vivo activities against P. digitatum or P. ulaiense were different. Candida cantarellii and one strain of Pichia subpelliculosa produced a significant reduction of the lesion area caused by the pathogenic moulds P. digitatum and P. ulaiense, and could be used in a biocontrol product formulation.

  14. Detection and identification of wild yeasts in lager breweries.

    Science.gov (United States)

    van der Aa Kühle, A; Jespersen, L

    1998-09-08

    Wild yeasts were detected in 41 out of 101 brewery yeast samples investigated using six different selective principles. Malt extract, yeast extract, glucose, peptone (MYGP) agar supplemented with 195 ppm CuSO4 was found to be the most effective selective principle, detecting wild yeasts in 80% of the contaminated samples. Both Saccharomyces and non-Saccharomyces wild yeasts were detected on this medium. Lysine medium, crystal violet medium and incubation of non-selective media at 37 degrees C detected wild yeasts in 46-56% of the contaminated samples. On using actidione medium, only 20% of the wild yeasts were detected. The combined use of MYGP supplemented with 195 ppm CuSO4 and one of the other selective principles did not improve the recovery of the wild yeasts. The wild yeasts found consisted of Saccharomyces cerevisiae (57%), Pichia spp. (28%) and Candida spp. (15%). Using the API ID 32 C kit, 35 different assimilation profiles were obtained for the 124 wild yeast isolates investigated. All isolates were capable of glucose assimilation, whereas only 79% of the isolates assimilated saccharose, 75% maltose, 70% galactose, 65% raffinose and 65% lactate. Lactose, inositol, rhamnose and glucuronate were not assimilated by any of the isolates. The differences in assimilation pattern did not reflect any differences in recovery by the selective principles investigated. The majority of the wild yeast isolates investigated were capable of growth in wort and beer, indicating their possible role as spoilage organisms. The Sacch. cerevisiae isolates were found to be the most hazardous, with some isolates being capable of extensive growth in bottled beer within seventeen days at ambient temperature.

  15. MAGNETIC FIELD EFFECT ON YEAST SACCHAROMYCES CEREVIISIIAE ACTIVITY AT GRAPE MUST FERMENTATION

    OpenAIRE

    Bayraktar, V.

    2013-01-01

    Treatment of yeast cultures using magnetic fields enables us to gain a better understanding of the magnetic fields’ action on enzyme activity and the fluctuation of macroand micro-element concentrations within yeast cultures. For this purpose, the two following groups of yeast were studied: laboratory yeast cultures isolated from regional grape must and commercial yeast cultures that are commonly used in the wine industry. Both yeast groups were biochemically tested with and without magnetic ...

  16. Surface Modifying Substances that Reduce Apparent Yeast Cell Hydrophobicity

    Directory of Open Access Journals (Sweden)

    Lisa Colling

    2005-01-01

    Full Text Available Conclusions. Several commercially available compounds were able to block binding of styrene microspheres to yeast. Some of the binding activity appeared to be attributable to mannose-containing surface components. These findings have implications for formulating therapeutic products that might block yeast binding to tissues.

  17. Occurrence and function of yeasts in Asian indigenous fermented foods

    NARCIS (Netherlands)

    Aidoo, K.E.; Nout, M.J.R.; Sarkar, P.K.

    2006-01-01

    In the Asian region, indigenous fermented foods are important in daily life. In many of these foods, yeasts are predominant and functional during the fermentation. The diversity of foods in which yeasts predominate ranges from leavened bread-like products such as nan and idli, to alcoholic beverages

  18. Bipolar budding in yeasts - an electron microscope study

    NARCIS (Netherlands)

    Kreger-van Rij, N.J.W.; Veenhuis, M.

    1971-01-01

    Bud formation in yeasts with bipolar budding was studied by electron microscopy of thin sections. Budding in yeasts of the species Saccharomycodes ludwigii, Hanseniaspora valbyensis and Wickerhamia fluorescens resulted in concentric rings of scar ridges on the wall of the mother cell. The wall

  19. Occurrence and function of yeasts in Asian indigenous fermented foods

    NARCIS (Netherlands)

    Aidoo, K.E.; Nout, M.J.R.; Sarkar, P.K.

    2006-01-01

    In the Asian region, indigenous fermented foods are important in daily life. In many of these foods, yeasts are predominant and functional during the fermentation. The diversity of foods in which yeasts predominate ranges from leavened bread-like products such as nan and idli, to alcoholic beverages

  20. Characterisation of palm wine yeast isolates for industrial utilisation

    African Journals Online (AJOL)

    Administrator

    2006-10-02

    Oct 2, 2006 ... make this wine a veritable medium for the growth of a consortium of ... after isolation on glucose yeast agar (GYA) and yeast malt agar. (YMA) (Biolife). ... lactose, raffinose, soluble starch, D-xylose, L-arabinose, and D- ribose.

  1. Biotechnology of non-Saccharomyces yeasts--the ascomycetes.

    Science.gov (United States)

    Johnson, Eric A

    2013-01-01

    Saccharomyces cerevisiae and several other yeast species are among the most important groups of biotechnological organisms. S. cerevisiae and closely related ascomycetous yeasts are the major producer of biotechnology products worldwide, exceeding other groups of industrial microorganisms in productivity and economic revenues. Traditional industrial attributes of the S. cerevisiae group include their primary roles in food fermentations such as beers, cider, wines, sake, distilled spirits, bakery products, cheese, sausages, and other fermented foods. Other long-standing industrial processes involving S. cerevisae yeasts are production of fuel ethanol, single-cell protein (SCP), feeds and fodder, industrial enzymes, and small molecular weight metabolites. More recently, non-Saccharomyces yeasts (non-conventional yeasts) have been utilized as industrial organisms for a variety of biotechnological roles. Non-Saccharomyces yeasts are increasingly being used as hosts for expression of proteins, biocatalysts and multi-enzyme pathways for the synthesis of fine chemicals and small molecular weight compounds of medicinal and nutritional importance. Non-Saccharomyces yeasts also have important roles in agriculture as agents of biocontrol, bioremediation, and as indicators of environmental quality. Several of these products and processes have reached commercial utility, while others are in advanced development. The objective of this mini-review is to describe processes currently used by industry and those in developmental stages and close to commercialization primarily from non-Saccharomyces yeasts with an emphasis on new opportunities. The utility of S. cerevisiae in heterologous production of selected products is also described.

  2. A vaccine grade of yeast Saccharomyces cerevisiae expressing mammalian myostatin

    Directory of Open Access Journals (Sweden)

    Zhang Tingting

    2012-12-01

    Full Text Available Abstract Background Yeast Saccharomyces cerevisiae is a widely-used system for protein expression. We previously showed that heat-killed whole recombinant yeast vaccine expressing mammalian myostatin can modulate myostatin function in mice, resulting in increase of body weight and muscle composition in these animals. Foreign DNA introduced into yeast cells can be lost soon unless cells are continuously cultured in selection media, which usually contain antibiotics. For cost and safety concerns, it is essential to optimize conditions to produce quality food and pharmaceutical products. Results We developed a simple but effective method to engineer a yeast strain stably expressing mammalian myostatin. This method utilized high-copy-number integration of myostatin gene into the ribosomal DNA of Saccharomyces cerevisiae. In the final step, antibiotic selection marker was removed using the Cre-LoxP system to minimize any possible side-effects for animals. The resulting yeast strain can be maintained in rich culture media and stably express mammalian myostatin for two years. Oral administration of the recombinant yeast was able to induce immune response to myostatin and modulated the body weight of mice. Conclusions Establishment of such yeast strain is a step further toward transformation of yeast cells into edible vaccine to improve meat production in farm animals and treat human muscle-wasting diseases in the future.

  3. Improving industrial yeast strains: exploiting natural and artificial diversity

    Science.gov (United States)

    Steensels, Jan; Snoek, Tim; Meersman, Esther; Nicolino, Martina Picca; Voordeckers, Karin; Verstrepen, Kevin J

    2014-01-01

    Yeasts have been used for thousands of years to make fermented foods and beverages, such as beer, wine, sake, and bread. However, the choice for a particular yeast strain or species for a specific industrial application is often based on historical, rather than scientific grounds. Moreover, new biotechnological yeast applications, such as the production of second-generation biofuels, confront yeast with environments and challenges that differ from those encountered in traditional food fermentations. Together, this implies that there are interesting opportunities to isolate or generate yeast variants that perform better than the currently used strains. Here, we discuss the different strategies of strain selection and improvement available for both conventional and nonconventional yeasts. Exploiting the existing natural diversity and using techniques such as mutagenesis, protoplast fusion, breeding, genome shuffling and directed evolution to generate artificial diversity, or the use of genetic modification strategies to alter traits in a more targeted way, have led to the selection of superior industrial yeasts. Furthermore, recent technological advances allowed the development of high-throughput techniques, such as ‘global transcription machinery engineering’ (gTME), to induce genetic variation, providing a new source of yeast genetic diversity. PMID:24724938

  4. Efficient expression of the yeast metallothionein gene in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Berka, T.; Shatzman, A.; Zimmerman, J.; Strickler, J.; Rosenberg, M.

    1988-01-01

    The yeast metallothionein gene CUP1 was cloned into a bacterial expression system to achieve efficient, controlled expression of the stable, unprocessed protein product. The Escherichia coli-synthesized yeast metallothionein bound copper, cadmium, zinc, indicating that the protein was functional. Furthermore, E. coli cells expressing CUP1 acquired a new, inducible ability to selectively sequester heavy metal ions from the growth medium.

  5. Molecular identification of uncommon clinical yeast species in Iran

    Directory of Open Access Journals (Sweden)

    Ladan Karimi

    2015-03-01

    Conclusion: We identified several rare clinical isolates selected from a big collection at the species level by ITS-sequencing. As the list of yeast species as opportunistic human fungal infections is increasing dramatically, and many isolates remain unidentified using conventional methods, more sensitive and specific advanced approaches help us to clarify the aspects of microbial epidemiology of the yeast infections.

  6. Extrinsic allergic alveolitis after exposure to the yeast Rhodotorula rubra.

    Science.gov (United States)

    Siersted, H C; Gravesen, S

    1993-05-01

    A case of extrinsic allergic alveolitis following exposure to the red yeast Rhodotorula rubra is reported--to our knowledge, for the first time. Extensive growth of the yeast in the patient's environment was demonstrated, explaining an elevated titer of Rhodotorula-specific precipitating antibodies in his serum. A bronchial provocation test confirmed the diagnosis.

  7. The making of biodiversity across the yeast subphyllum

    Science.gov (United States)

    Goals for this research project are to determine how the functional diversity of the yeast subphylum is encoded, and to reconstruct the history of yeasts to elucidate the tempo and mode of functional diversification. The impact of this work will be to integrate discoveries within broadly disseminate...

  8. [Yeasts in domestic animals: species identification and susceptibility to antifungals].

    Science.gov (United States)

    Hamal, Petr; Koukalová, Dagmar

    2010-02-01

    Yeasts frequently colonize various kinds of domestic animals, but may also cause serious diseases. The aim of this study was to identify yeast isolates collected from dogs, cows and pigs, and to determine their in vitro antifungal susceptibility. Fifty-six yeast isolates from dogs (n = 24), cows (n = 20), and pigs (n = 12) were investigated. Appearance of colonies grown on Sabouraud agar, micromorphology on rice agar, as well as assimilation and fermentation of various carbon and nitrogen sources were evaluated. Susceptibility to six antifungals (flucytosine, amphotericin B, miconazole, ketoconazole, itraconazole and fluconazole) was determined semiquantitatively using the commercially available Fungitest kit (Bio-Rad Laboratories). Ten yeast species were identified in dogs with relatively even distribution. On the other hand, cow and pig were clearly dominated by Candida krusei (from 7 species) and Candida rugosa (from 5 species), respectively. Further, most of yeast isolates exhibited good susceptibility to the antifungals tested particularly to amphotericin B, ketoconazole and itraconazole. Based on results, it can be concluded that significant differences in the species spectrum and distribution were documented between groups of yeasts from dogs, cows and pigs. This is probably due to different environmental conditions and the endogenous origin of the yeast isolates. Mostly good susceptibility to systemic antifungals should positively influence the therapy of diseases caused by yeasts in veterinary medicine.

  9. Identification of Yeasts Present in Sour Fermented Foods and Fodder

    NARCIS (Netherlands)

    Middelhoven, W.J.

    2002-01-01

    This paper deals with rapid methods for identification of 50 yeast species frequently isolated from foods and fodders that underwent a lactic acid fermentation. However, many yeast species present in olive brine, alpechin, and other olive products were not treated. The methods required for identific

  10. Performance of baker's yeast produced using date syrup substrate ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-05-24

    May 24, 2010 ... 1Date Palm Research Center, King Faisal University, Al-Hassa, 31982, Saudi Arabia. 2King Abdulaziz City ... relationship between total Arabic bread quality and yeast gassing power. ... showed that higher productivity of baker's yeast was observed ..... American Association of Cereal Chemists.. Approved.

  11. Effect of salt hyperosmotic stress on yeast cell viability

    Directory of Open Access Journals (Sweden)

    Logothetis Stelios

    2007-01-01

    Full Text Available During fermentation for ethanol production, yeasts are subjected to different kinds of physico-chemical stresses such as: initially high sugar concentration and low temperature; and later, increased ethanol concentrations. Such conditions trigger a series of biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding osmostress, many studies have been focused on transcriptional activation and gene expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present work was to further our understanding of wine yeast performance during fermentations under osmotic stress conditions. Specifically, the research work focused on the evaluation of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13, particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress conditions energized specific genes to enable yeast cells to survive under stressful conditions. Experiments were designed by pretreating cells with different sodium chloride concentrations (NaCl: 4%, 6% and 10% w/v growing in defined media containing D-glucose and evaluating the impact of this on yeast growth and viability. Subsequent fermentation cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v using salt-adapted cells as inocula. We present evidence that osmostress induced by mild salt pre-treatments resulted in beneficial influences on both cell viability and fermentation performance of an industrial wine yeast strain.

  12. Interactions between yeasts, fungicides and apple fruit russeting

    NARCIS (Netherlands)

    Gildemacher, P.R.; Heijne, B.; Silvestri, M.; Houbraken, J.; Hoekstra, E.; Theelen, B.; Boekhout, T.

    2006-01-01

    The effect of inoculations with yeasts occurring on apple surfaces and fungicide treatments on the russeting of Elstar apples was studied. Captan, dithianon and a water treatment were implemented to study the interaction between the fungicides, the inoculated yeast species and Aureobasidium pullulan

  13. Yeast profile in Gouda cheese during processing and ripening.

    Science.gov (United States)

    Welthagen, J J; Viljoen, B C

    1998-06-16

    The yeasts present in Gouda cheese during processing were monitored in a single cheese factory during a 32 day ripening period. Despite the predominance of lactic acid bacteria during Gouda making, yeasts played a significant role in the ripening process in reaching counts as high as 10(5) cfu g(-1) at the later stages of ripening. The increase in the number of yeasts corresponded with the depletion in lactose content and the simultaneous stabilization of lactic acid bacteria numbers. The sources of yeast contamination which may lead to contamination of the curd were also determined. The brine and equipment surfaces were responsible for the highest yield of contaminating yeasts. A diverse variety of 23 yeast species representing 13 genera were present in the factory environment, during processing and ripening. Samples were taken at critical control points in the manufacturing process and analysed after incubation at 25 degrees C for 96 h. Although a broad spectrum of yeasts were found in Gouda cheese, Debaryomyces hansenii was the most abundant yeast isolated. Other species encountered were Saccharomyces cerevisiae and Yarrowia lipolytica, Kluyveromyces marxianus, Torulaspora delbrueckii, Rhodotorula glutinis, Cryptococcus albidus and Candida catenulata.

  14. Bipolar budding in yeasts - an electron microscope study

    NARCIS (Netherlands)

    Kreger-van Rij, N.J.W.; Veenhuis, M.

    1971-01-01

    Bud formation in yeasts with bipolar budding was studied by electron microscopy of thin sections. Budding in yeasts of the species Saccharomycodes ludwigii, Hanseniaspora valbyensis and Wickerhamia fluorescens resulted in concentric rings of scar ridges on the wall of the mother cell. The wall betwe

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

    Science.gov (United States)

    Deutch, Charles E.; Marshall, Pamela A.

    2008-01-01

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

  16. Using Microsatellites to Identify Yeast Strains in Beer

    Science.gov (United States)

    Bruke, Alexandria; Van Brocklin, Jennifer; Rivest, Jason; Prenni, Jessica E.; Ibrahim, Hend

    2012-01-01

    Yeast is an integral part of the brewing process and is responsible for much of the taste and characteristics of beer. During the brewing process, yeast is subject to ageing and stress factors that can result in growth inhibition, decreased genetic stability, and changes in cell membrane stability. Characterization of yeast species used in industrial fermentation (e.g. S. cerevisiae) is of great importance to the brewing industry. The objective of this study was to develop an assay to identify yeast strains commonly used in the production of beer. Six microsatellite regions of DNA (comprised of AAT) were used as sequence tagged site markers (STR) to identify and compare yeast samples and to determine strain within a species. Labeled primers ScATT (1-6) targeting these six microsatellite regions were designed using 6-FAM, VIC, NED and PET 5′-fluorescent labels. The six regions were amplified, in a single reaction, from extracted yeast genomic DNA using a modified multiplex-PCR protocol and the labeled PCR products were analyzed on an ABI 3130xl Genetic Analyzer. Using this approach 6 STR markers were amplified in a single multiplex reaction from a commercially utilized yeast strain provided by Odell Brewing. Different alleles were distinguished based on the size of each STR and the labeling fluorophore. The procedures developed in this study will provide an invaluable tool for the quality control of yeast strains in the brewing industry.

  17. Specialist nectar-yeasts decline with urbanization in Berlin

    Science.gov (United States)

    Wehner, Jeannine; Mittelbach, Moritz; Rillig, Matthias C.; Verbruggen, Erik

    2017-01-01

    Nectar yeasts are common inhabitants of insect-pollinated flowers but factors determining their distribution are not well understood. We studied the influence of host identity, environmental factors related to pollution/urbanization, and the distance to a target beehive on local distribution of nectar yeasts within Robinia pseudoacacia L. and Tilia tomentosa Moench in Berlin, Germany. Nectar samples of six individuals per species were collected at seven sites in a 2 km radius from each target beehive and plated on YM-Agar to visualise the different morphotypes, which were then identified by sequencing a section of the 26S rDNA gene. Multivariate linear models were used to analyze the effects of all investigated factors on yeast occurrence per tree. Yeast distribution was mainly driven by host identity. The influence of the environmental factors (NO2, height of construction, soil sealing) strongly depended on the radius around the tree, similar to the distance of the sampled beehive. Incidence of specialist nectar-borne yeast species decreased with increasing pollution/urbanization index. Given that specialist yeast species gave way to generalist yeasts that have a reduced dependency on pollinators for between-flower dispersal, our results indicate that increased urbanization may restrict the movement of nectar-specialized yeasts, via limitations of pollinator foraging behavior. PMID:28358006

  18. Production of glycolipid biosurfactants by basidiomycetous yeasts.

    Science.gov (United States)

    Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2009-05-01

    BSs (biosurfactants) produced by various micro-organisms show unique properties (e.g. mild production conditions, lower toxicity, higher biodegradability and environmental compatibility) compared with chemically synthesized surfactants. The numerous advantages of BSs have prompted applications not only in the food, cosmetic and pharmaceutical industries but also in environmental protection and energy-saving technology. Among BSs, glycolipid types are the most promising, owing to their high productivity from renewable resources and versatile biochemical properties. MELs (mannosylerythritol lipids), which are glycolipid BSs abundantly produced by basidiomycetous yeasts such as strains of Pseudozyma, exhibit not only excellent interfacial properties, but also remarkable differentiation-inducing activities against human leukaemia cells. MELs also show high binding affinity towards different immunoglobulins and lectins. Recently, a cationic liposome bearing MEL has been demonstrated to increase dramatically the efficiency of gene transfection into mammalian cells. These features of BSs should broaden their application in new advanced technologies. In the present review the current status of research and development on glycolipid BSs, especially their production by Pseudozyma yeasts, is described.

  19. Multiple Functions of Sterols in Yeast Endocytosis

    Science.gov (United States)

    Heese-Peck, Antje; Pichler, Harald; Zanolari, Bettina; Watanabe, Reika; Daum, Günther; Riezman, Howard

    2002-01-01

    Sterols are essential factors for endocytosis in animals and yeast. To investigate the sterol structural requirements for yeast endocytosis, we created a variety of ergΔ mutants, each accumulating a distinct set of sterols different from ergosterol. Mutant erg2Δerg6Δ and erg3Δerg6Δ cells exhibit a strong internalization defect of the α-factor receptor (Ste2p). Specific sterol structures are necessary for pheromone-dependent receptor hyperphosphorylation, a prerequisite for internalization. The lack of phosphorylation is not due to a defect in Ste2p localization or in ligand–receptor interaction. Contrary to most known endocytic factors, sterols seem to function in internalization independently of actin. Furthermore, sterol structures are required at a postinternalization step of endocytosis. ergΔ cells were able to take up the membrane marker FM4-64, but exhibited defects in FM4-64 movement through endosomal compartments to the vacuole. Therefore, there are at least two roles for sterols in endocytosis. Based on sterol analysis, the sterol structural requirements for these two processes were different, suggesting that sterols may have distinct functions at different places in the endocytic pathway. Interestingly, sterol structures unable to support endocytosis allowed transport of the glycosylphosphatidylinositol-anchored protein Gas1p from the endoplasmic reticulum to Golgi compartment. PMID:12181337

  20. The natural history of yeast prions.

    Science.gov (United States)

    Tuite, Mick F

    2013-01-01

    Although prions were first discovered through their link to severe brain degenerative diseases in animals, the emergence of prions as regulators of the phenotype of the yeast Saccharomyces cerevisiae and the filamentous fungus Podospora anserina has revealed a new facet of prion biology. In most cases, fungal prions are carried without apparent detriment to the host cell, representing a novel form of epigenetic inheritance. This raises the question of whether or not yeast prions are beneficial survival factors or actually gives rise to a "disease state" that is selected against in nature. To date, most studies on the impact of fungal prions have focused on laboratory-cultivated "domesticated" strains of S. cerevisiae. At least eight prions have now been described in this species, each with the potential to impact on a wide range of cellular processes. The discovery of prions in nondomesticated strains of S. cerevisiae and P. anserina has confirmed that prions are not simply an artifact of "domestication" of this species. In this review, I describe what we currently know about the phenotypic impact of fungal prions. I then describe how the interplay between host genotype and the prion-mediated changes can generate a wide array of phenotypic diversity. How such prion-generated diversity may be of benefit to the host in survival in a fluctuating, often hazardous environment is then outlined. Prion research has now entered a new phase in which we must now consider their biological function and evolutionary significance in the natural world.

  1. Thermodynamic study of yeast phosphoglycerate kinase.

    Science.gov (United States)

    Hu, C Q; Sturtevant, J M

    1987-01-13

    Enthalpies of binding of MgADP, MgATP, and 3-phosphoglycerate to yeast phosphoglycerate kinase have been determined by flow calorimetry at 9.95-32.00 degrees C. Combination of these data with published dissociation constants [Scopes, R.K. (1978) Eur. J. Biochem. 91, 119-129] yielded the following thermodynamic parameters for the binding of 3-phosphoglycerate at 25 degrees C: delta Go = -6.76 +/- 0.11 kcal mol-1, delta H = 3.74 +/- 0.08 kcal mol-1, delta So = 35.2 +/- 0.6 cal K-1 mol-1, and delta Cp = 0.12 +/- 0.32 kcal K-1 mol-1. The thermal unfolding of phosphoglycerate kinase in the absence and presence of the ligands listed above was studied by differential scanning calorimetry. The temperature of half-completion, t 1/2, of the denaturation and the denaturational enthalpy are increased by the binding of the ligands, the increase in t 1/2 being a manifestation of Le Chatelier's principle and that in enthalpy reflecting the enthalpy of dissociation of the ligand. Only one denaturational peak was observed under all conditions, and in contrast with the case of yeast hexokinase [Takahashi, K., Casey, J.L., & Sturtevant, J.M. (1981) Biochemistry 20, 4693-4697], no definitive evidence for the unfolding of more than one domain was obtained.

  2. Perchlorate Reduction by Yeast for Mars Exploration

    Science.gov (United States)

    Sharma, Alaisha

    2015-01-01

    Martian soil contains high levels (0.6 percentage by mass) of calcium perchlorate (Ca(ClO4)2), which readily dissociates into calcium and the perchlorate ion (ClO4-) in water. Even in trace amounts, perchlorates are toxic to humans and have been implicated in thyroid dysfunction. Devising methods to lessen perchlorate contamination is crucial to minimizing the health risks associated with human exploration and colonization of Mars. We designed a perchlorate reduction pathway, which sequentially reduces perchlorate to chloride (Cl-) and oxygen (O2), for implementation in the yeast Saccharomyces cerevisiae. Using genes obtained from perchlorate reducing bacteria Azospira oryzae and Dechloromonas aromatica, we plan to assemble this pathway directly within S. cerevisiae through recombinational cloning. A perchlorate reduction pathway would enable S. cerevisiae to lower perchlorate levels and produce oxygen, which may be harvested or used directly by S. cerevisiae for aerobic growth and compound synthesis. Moreover, using perchlorate as an external electron acceptor could improve the efficiency of redox-imbalanced production pathways in yeast. Although several perchlorate reducing bacteria have been identified and utilized in water treatment systems on Earth, the widespread use of S. cerevisiae as a synthetic biology platform justifies the development of a perchlorate reducing strain for implementation on Mars.

  3. Yeast lipid metabolism at a glance.

    Science.gov (United States)

    Klug, Lisa; Daum, Günther

    2014-05-01

    During the last decades, lipids have gained much attention due to their involvement in health and disease. Lipids are required for the formation of membranes and contribute to many different processes such as cell signaling, energy supply, and cell death. Various organelles such as the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets are involved in lipid metabolism. The yeast Saccharomyces cerevisiae has become a reliable model organism to study biochemistry, molecular biology, and cell biology of lipids. The availability of mutants bearing defects in lipid metabolic pathways and the ease of manipulation by culture conditions facilitated these investigations. Here, we summarize the current knowledge about lipid metabolism in yeast. We grouped this large topic into three sections dealing with (1) fatty acids; (2) membrane lipids; and (3) storage lipids. Fatty acids serve as building blocks for the synthesis of membrane lipids (phospholipids, sphingolipids) and storage lipids (triacylglycerols, steryl esters). Phospholipids, sterols, and sphingolipids are essential components of cellular membranes. Recent investigations addressing lipid synthesis, degradation, and storage as well as regulatory aspects are presented. The role of enzymes governing important steps of the different lipid metabolic pathways is described. Finally, the link between lipid metabolic and dynamic processes is discussed.

  4. An overview of macroautophagy in yeast.

    Science.gov (United States)

    Wen, Xin; Klionsky, Daniel J

    2016-05-08

    Macroautophagy is an evolutionarily conserved dynamic pathway that functions primarily in a degradative manner. A basal level of macroautophagy occurs constitutively, but this process can be further induced in response to various types of stress including starvation, hypoxia and hormonal stimuli. The general principle behind macroautophagy is that cytoplasmic contents can be sequestered within a transient double-membrane organelle, an autophagosome, which subsequently fuses with a lysosome or vacuole (in mammals, or yeast and plants, respectively), allowing for degradation of the cargo followed by recycling of the resulting macromolecules. Through this basic mechanism, macroautophagy has a critical role in cellular homeostasis; however, either insufficient or excessive macroautophagy can seriously compromise cell physiology, and thus, it needs to be properly regulated. In fact, a wide range of diseases are associated with dysregulation of macroautophagy. There has been substantial progress in understanding the regulation and molecular mechanisms of macroautophagy in different organisms; however, many questions concerning some of the most fundamental aspects of macroautophagy remain unresolved. In this review, we summarize current knowledge about macroautophagy mainly in yeast, including the mechanism of autophagosome biogenesis, the function of the core macroautophagic machinery, the regulation of macroautophagy and the process of cargo recognition in selective macroautophagy, with the goal of providing insights into some of the key unanswered questions in this field.

  5. Optimization of Fermentation Condition of Yeast Culture

    Institute of Scientific and Technical Information of China (English)

    WANG Qiuju; XU Li; CUI Yizhe

    2008-01-01

    Culture condition of every phase for fermentation of yeast culture was studied, and its solid and liquid conditions of elaboration were optimized to improve the total counts of living cells.Results showed that microzyme grew best at 30℃ when solid fermented,and the count of the living cells reached the tiptop with pH 5.5.The count of Candida tropicalis could reach 137.96×109 cfu·g-1,the count of Saccharomyces cerevisia could reach 134.62×109 cfu·g-1;the best liquid fermentation condition for cell-wall broken was 50℃ for 28 h,the rate of cell-wall broken could reach 80% at least;the rate of vitamin loss in yeast could be the minimun, the loss rate of vitamin B1 in Candida tropicalis and Saccharomyces cerevisiae was 8.71% and 19.54% respectively, the loss rate of vitamin B2 was 19.39% and 13.18%,respectively,and the loss rate of vitamin B6 was 6.3% and 3.04%,respectively.

  6. Parameters affecting methanol utilization by yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Foda, M.S.; El-Masry, H.G.

    1981-01-01

    Screening of 28 yeast cultures, representing 22 species of various yeasts, with respect to their capabilities to assimilate methanol, has shown that this property was mostly found in certain species of the two genera Hansenula and Candida. When methanol was used as a sole carbon source for a methanol-adapted strain of Hansenula polymorpha, a linear yield response could be obtained with increasing alcohol up to 2% concentration. The amount of inoculum proved to be the decisive factor in determining a priori the ability of the organism to grow at 6% methanol as final concentration. The optimum pH values for growth ranged between 4.5-5.5 with no growth at pH 6.5 or higher. A marked growth stimulation was obtained when the medium was supplied with phosphate up to 0.08 M as final concentration. Within the nitrogen sources tested, corn steep liquor concentrate gave the highest yield of cells. The significance of the obtained results are discussed with reference to feasibilities of application.

  7. Yeast diversity and native vigor for flavor phenotypes.

    Science.gov (United States)

    Carrau, Francisco; Gaggero, Carina; Aguilar, Pablo S

    2015-03-01

    Saccharomyces cerevisiae, the yeast used widely for beer, bread, cider, and wine production, is the most resourceful eukaryotic model used for genetic engineering. A typical concern about using engineered yeasts for food production might be negative consumer perception of genetically modified organisms. However, we believe the true pitfall of using genetically modified yeasts is their limited capacity to either refine or improve the sensory properties of fermented foods under real production conditions. Alternatively, yeast diversity screening to improve the aroma and flavors could offer groundbreaking opportunities in food biotechnology. We propose a 'Yeast Flavor Diversity Screening' strategy which integrates knowledge from sensory analysis and natural whole-genome evolution with information about flavor metabolic networks and their regulation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Stabilization and encapsulation of photosensitive resveratrol within yeast cell.

    Science.gov (United States)

    Shi, Guorong; Rao, Liqun; Yu, Huazhong; Xiang, Hua; Yang, Hua; Ji, Runa

    2008-02-12

    The photosensitive resveratrol was successfully encapsulated in yeast cells for the first time, as characterized by FT-IR spectra, fluorescence and confocal micrographs of the yeast cells, resveratrol and microcapsules. The release characteristic of the obtained yeast-encapsulated resveratrol in simulated gastric fluid was evaluated, and its storage stability as a powder was investigated at 25 degrees C/75% relative humidity (RH), 25 degrees C/90% RH and 60 degrees C under the laboratory fluorescent lighting conditions (ca. 300 lx) or in the dark. Also, the scavenging capacity of yeast-encapsulated resveratrol on DPPH radical was compared with that of non-encapsulated resveratrol. It could be demonstrated clearly that no chemical changes occurred during the encapsulation. Besides, the DPPH radical-scavenging activity increased after the encapsulation. In addition, the yeast-encapsulated resveratrol exhibited good stability, and its bioavailability was enhanced as a result of increased solubility of resveratrol and sustained releasing.

  9. Immuno-assay techniques for detecting yeasts in foods.

    Science.gov (United States)

    Middelhoven, W J; Notermans, S

    1993-06-25

    A brief literature review on immuno-assay of yeast cell wall antigens is given. Special attention is paid to extracellular, thermostable yeast antigens (EPS), which are released to the growth medium by many yeast species. The EPS of Saccharomyces cerevisiae and of Stephanoascus ciferrii (syn. Candida ciferrii) could be specifically and sensitively detected by a sandwich ELISA, using an IgG raised in rabbits immunized with the EPS of these yeasts. The EPS ELISA of three basidiomycetous yeasts tested was not specific, that of Geotrichum candidum was genus-specific but was not sensitive. The EPS of Zygosaccharomyces bailii could be detected in a highly specific competitive ELISA but not in a sandwich ELISA or in a latex agglutination test.

  10. Phenotypic Diagnosis of Lineage and Differentiation During Sake Yeast Breeding.

    Science.gov (United States)

    Ohnuki, Shinsuke; Okada, Hiroki; Friedrich, Anne; Kanno, Yoichiro; Goshima, Tetsuya; Hasuda, Hirokazu; Inahashi, Masaaki; Okazaki, Naoto; Tamura, Hiroyasu; Nakamura, Ryo; Hirata, Dai; Fukuda, Hisashi; Shimoi, Hitoshi; Kitamoto, Katsuhiko; Watanabe, Daisuke; Schacherer, Joseph; Akao, Takeshi; Ohya, Yoshikazu

    2017-08-07

    Sake yeast was developed exclusively in Japan. Its diversification during breeding remains largely uncharacterized. To evaluate the breeding processes of the sake lineage, we thoroughly investigated the phenotypes and differentiation of 27 sake yeast strains using high-dimensional, single-cell, morphological phenotyping. Although the genetic diversity of the sake yeast lineage is relatively low, its morphological diversity has expanded substantially compared to that of the Saccharomycescerevisiae species as a whole. Evaluation of the different types of breeding processes showed that the generation of hybrids (crossbreeding) has more profound effects on cell morphology than the isolation of mutants (mutation breeding). Analysis of phenotypic robustness revealed that some sake yeast strains are more morphologically heterogeneous, possibly due to impairment of cellular network hubs. This study provides a new perspective for studying yeast breeding genetics and micro-organism breeding strategies. Copyright © 2017 Ohnuki et al.

  11. Activation of waste brewer's yeast Saccharomyces cerevisiae for bread production

    Directory of Open Access Journals (Sweden)

    Popov Stevan D.

    2005-01-01

    Full Text Available The waste brewer's yeast S. cerevisiae (activated and non-activated was compared with the commercial baker's yeast regarding the volume of developed gas in dough, volume and freshness stability of produced bread. The activation of waste brewer's yeast resulted in the increased volume of developed gas in dough by 100% compared to non-activated brewer's yeast, and the obtained bread is of more stable freshness compared to bread produced with baker's yeast. The activation of BY affects positively the quality of produced bread regarding bread volume. The volume of developed gas in dough prepared with the use of non-activated BY was not sufficient, therefore, it should not be used as fermentation agent, but only as an additive in bread production process for bread freshness preservation. Intense mixing of dough results in more compressible crumb 48 hrs after baking compared to high-speed mixing.

  12. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure

    Science.gov (United States)

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

    2014-05-01

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

  13. Isolation and Identification of Yeasts from Tibet Kefir

    Directory of Open Access Journals (Sweden)

    Yun Li

    2015-02-01

    Full Text Available The occurrence and distribution of yeasts in Tibet kefir were investigated in this study. Five samples of Tibetan kefir from Tibet and surrounding areas were collected for yeast isolation. Based on physiological, biochemical characteristics and molecular identification results, eight species of yeast were isolated and identified from Tibet kefir, including Saccharomyces cerevisiae, Pichia fermentans, Debaryomyces hansenii, Rhodotorula mucilaginosa, Candida zeylanoide, Candida parapsilosis, Kluyveromyces marxianus and Kazachstania unispora. Among the test samples, K. marxianus, Ka. unispora and P. fermentans were the highest three species in frequency of occurrence of yeast isolates. C. zeylanoides, C. parapsilosis and R. mucilaginosa were first found the occurrence in Tibet kefir. The results provided new information of yeast composition and biodiversity of Tibet kefir.

  14. Yeast systems for the commercial production of heterologous proteins.

    Science.gov (United States)

    Buckholz, R G; Gleeson, M A

    1991-11-01

    Yeasts are attractive hosts for the production of heterologous proteins. Unlike prokaryotic systems, their eukaryotic subcellular organization enables them to carry out many of the post-translational folding, processing and modification events required to produce "authentic" and bioactive mammalian proteins. In addition, they retain the advantages of a unicellular microorganism, with respect to rapid growth and ease of genetic manipulation. The vast majority of yeast expression work has focused on the well-characterized baker's yeast Saccharomyces cerevisiae. However, with the development of DNA transformation technologies, a growing number of non-Saccharomyces yeasts are becoming available as hosts for recombinant polypeptide production. These include Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, Schizosaccharomyces pombe, Schwanniomyces occidentalis and Yarrowia lipolytica. The performance of these alternative yeast expression systems is reviewed here relative to S. cerevisiae, and the advantages and limitations of these systems are discussed.

  15. Lipid raft involvement in yeast cell growth and death.

    Science.gov (United States)

    Mollinedo, Faustino

    2012-01-01

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na(+), K(+), and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  16. Lipid raft involvement in yeast cell growth and death

    Directory of Open Access Journals (Sweden)

    Faustino eMollinedo

    2012-10-01

    Full Text Available The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Crytococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na+, K+ and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  17. Yeast identification in the clinical microbiology laboratory: phenotypical methods.

    Science.gov (United States)

    Freydiere, A M; Guinet, R; Boiron, P

    2001-02-01

    Emerging yeast pathogens are favoured by increasing numbers of immunocompromised patients and by certain current medical practices. These yeasts differ in their antifungal drug susceptibilities, and rapid species identification is imperative. A large variety of methods have been developed with the aim of facilitating rapid, accurate yeast identification. Significant recent commercial introductions have included species-specific direct enzymatic colour tests, differential chromogenic isolation plates, direct immunological tests, and enhanced manual and automated biochemical and enzymatic panels. Chromogenic isolation media demonstrate better detection rates of yeasts in mixed cultures than traditional media, and allow the direct identification of Candida albicans by means of colony colour. Comparative evaluation of rapid methods for C. albicans identification, including the germ tube test, shows that chromogenic media may be economically advantageous. Accurate tests for single species include the Bichrolatex Albicans and Krusei Color tests, both immunologically based, as well as the Remel Rapid Trehalose Assimilation Broth for C. glabrata. Among broad-spectrum tests, the RapID Yeast Plus system gives same-day identification of clinical yeasts, but performance depends on inoculum density and geographic isolate source. The API 20 C AUX system is considered a reference method, but newer systems such as Auxacolor and Fungichrom are as accurate and are more convenient. Among automated systems, the ID 32 C strip, the Vitek Yeast Biochemical Card and the Vitek 2 ID-YST system correctly identify >93% of common yeasts, but the ID-YST is the most accurate with uncommon yeasts, including C. dubliniensis. Spectroscopic methods such as Fourier transformed-infrared spectroscopy offer potential advantages for the future. Overall, the advantages of rapid yeast identification methods include relative simplicity and low cost. For all rapid methods, meticulous, standardized

  18. Antimicrobial activity of yeasts against some pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Gamal Younis

    2017-08-01

    Full Text Available Aim: This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species. Materials and Methods: A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR for detection of khs (kievitone hydratase and pelA (pectate degrading enzyme genes. Results: The recovery rate of yeasts from sausage was 20% (2/10 followed by kareish cheese, processed cheese, and butter 10% (1/10 each as well as raw milk 9% (9/100, and fruit yoghurt 30% (6/20. Different yeast species were recovered, namely, Candida kefyr (5 isolates, Saccharomyces cerevisiae (4 isolates, Candida intermedia (3 isolates, Candida tropicalis (2 isolates, Candida lusitaniae (2 isolates, and Candida krusei (1 isolate. khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa. Conclusion: The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jennifer R Bellon

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

  1. [Diversity and genetic stability of yeast flocculation caused by variation of tandem repeats in yeast flocculin genes].

    Science.gov (United States)

    Yue, Feng; Guo, Xuena; He, Xiuping; Zhang, Borun

    2013-07-01

    Yeast flocculation is described as a reversible, asexual and calcium dependent process, in which cells adhere to form flocs by interaction of specific cell surface proteins named flocculins on yeast cells with mannose residues present on the cell wall of adjacent yeast cells. Yeast flocculation provides a very economical and convenient pathway for separation of yeast cells from the fermentation broth or removal of heavy metal ions from effluent. A large number of tandem repeats have been found in genes encoding flocculins, which not only have great regulatory effect on the structure and function of flocculins, generating the diversity of flocculation characteristics, but lead to genetic instability in flocculation as well for driving slippage and recombination reactions within and between FLO genes. Here, the research progress in effect of variation of tandem repeats in FLO genes on flocculation characteristics and genetic stability were reviewed to direct and promote the controllable application of flocculation in industrial fermentation process and environmental remediation.

  2. Biocavity laser spectroscopy of genetically altered yeast cells and isolated yeast mitochondria

    Science.gov (United States)

    Gourley, Paul L.; Hendricks, Judy K.; McDonald, Anthony E.; Copeland, R. Guild; Naviaux, Robert K.; Yaffe, Michael P.

    2006-02-01

    We report an analysis of 2 yeast cell mutants using biocavity laser spectroscopy. The two yeast strains differed only by the presence or absence of mitochondrial DNA. Strain 104 is a wild-type (ρ +) strain of the baker's yeast, Saccharomyces cerevisiae. Strain 110 was derived from strain 104 by removal of its mitochondrial DNA (mtDNA). Removal of mtDNA causes strain 110 to grow as a "petite" (ρ -), named because it forms small colonies (of fewer cells because it grows more slowly) on agar plates supplemented with a variety of different carbon sources. The absence of mitochondrial DNA results in the complete loss of all the mtDNA-encoded proteins and RNAs, and loss of the pigmented, heme-containing cytochromes a and b. These cells have mitochondria, but the mitochondria lack the normal respiratory chain complexes I, III, IV, and V. Complex II is preserved because its subunits are encoded by genes located in nuclear DNA. The frequency distributions of the peak shifts produced by wild-type and petite cells and mitochondria show striking differences in the symmetry and patterns of the distributions. Wild-type ρ + cells (104) and mitochondria produced nearly symmetric, Gaussian distributions. The ρ - cells (110) and mitochondria showed striking asymmetry and skew that appeared to follow a Poisson distribution.

  3. Beneficial properties of probiotic yeast Saccharomyces boulardii

    Directory of Open Access Journals (Sweden)

    Tomičić Zorica M.

    2016-01-01

    Full Text Available Saccharomyces boulardii is unique probiotic and biotherapeutic yeast, known to survive in gastric acidity and it is not adversely affected or inhibited by antibiotics or does not alter or adversely affect the normal microbiota. S. boulardii has been utilized worldwide as a probiotic supplement to support gastrointestinal health. The multiple mechanisms of action of S. boulardii and its properties may explain its efficacy and beneficial effects in acute and chronic gastrointestinal diseases that have been confirmed by clinical trials. Caution should be taken in patients with risk factors for adverse events. Its potential application in various dairy foods could offer an alternative probiotic product to people suffering from antibiotic-associated diarrhea. This review discusses the evidence for efficacy and safety of S. boulardii as a probiotic for the prevention and therapy of gastrointestinal disorders in humans.

  4. Import of proteins into isolated yeast mitochondria.

    Science.gov (United States)

    Peleh, Valentina; Ramesh, Ajay; Herrmann, Johannes M

    2015-01-01

    Mitochondria are essential organelles of eukaryotic cells. The vast majority of mitochondrial proteins is encoded within the nuclear genome and translocated into various mitochondrial compartments after translation in the cytosol as preproteins. Even in rather primitive eukaryotes like yeasts, there are 700-1,000 different proteins that need to be recognized in the cytosol, directed to the protein translocases in the two mitochondrial membranes and sorted to their appropriate mitochondrial subcompartment. In vitro reconstituted import systems have proved to be important tools to study these processes in detail. Using isolated mitochondria and radioactively labeled precursor proteins, it was possible to identify several import machineries and pathways consisting of a large number of components during the last few decades.

  5. Cyanohydrin reactions enhance glycolytic oscillations in yeast

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Nielsen, Astrid Gram; Tortzen, Christian

    2015-01-01

    Synchronous metabolic oscillations can be induced in yeast by addition of glucose and removal of extracellular acetaldehyde (ACAx). Compared to other means of ACAx removal, cyanide robustly induces oscillations, indicating additional cyanide reactions besides ACA to lactonitrile conversion. Here......, (13)C NMR is used to confirm our previous hypothesis, that cyanide directly affects glycolytic fluxes through reaction with carbonyl-containing compounds. Intracellularly, at least 3 cyanohydrins were identified. Extracellularly, all signals could be identified and lactonitrile was found to account...... for ~66% of total cyanide removal. Simulations of our updated computational model show that intracellular cyanide reactions increase the amplitude of oscillations and that cyanide addition lowers [ACA] instantaneously. We conclude that cyanide provides the following means of inducing global oscillations...

  6. Production of high concentrations of yeast

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-10

    A microbe is aerobically cultured using O/sub 2/ or a gas rich in O/sub 2/. The grown cells are washed, concentrated and a portion of the cells used as a seed culture. Thus, Saccharomyces cerevisiae (bakers' yeast) was cultured in a jar fermentor by flow down system maintaining the dissolved O/sub 2/ at 2-5 mg/L; volume of the initial medium containing 30% glucose was 350 mL and the initial washed cell concentration was 50 g dry cells/L. After 12 hours of cultivation, the volume of the medium increased to 750 mL and the cell concentration rose to 102 g dry cells/L; the yield was 49% with respect to glucose. The cells were washed and the cultivation was repeated by use of the washed cells; cell concentration reached 105 g dry cells/L.

  7. Phyllosphere yeasts rapidly break down biodegradable plastics.

    Science.gov (United States)

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-11-29

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

  8. Yeast prions: Paramutation at the protein level?

    Science.gov (United States)

    Tuite, Mick F

    2015-08-01

    Prions are proteins that have the potential to refold into a novel conformation that templates the conversion of like molecules to the altered infectious form. In the yeast Saccharomyces cerevisiae, trans-generational epigenetic inheritance can be mediated by a number of structurally and functionally diverse prions. Prionogenesis can confer both loss-of-function and gain-of-function properties to the prion protein and this in turn can have a major impact on host phenotype, short-term adaptation and evolution of new traits. Prionogenesis shares a number of properties in common with paramutation and can be considered as a mitotically and meiotically heritable change in protein conformation induced by trans-interactions between homologous proteins.

  9. Organic growth factor requirements of some yeasts.

    Science.gov (United States)

    Madan, M; Gulati, N

    1980-01-01

    Some sporogenous yeasts (Brettanomyces bruxellensis, Debaryomyces hansenii, Hansenula ciferrii, Hansenula polymorpha, Pichia polymorpha, Saccharomycopsis guttulata, and Saccharomyces chevalieri), isolated from various fruits have been examined for their organic growth factor requisites. H. ciferrii was completely deficient in thiamine, biotin, inositol, riboflavin, niacin, and partially deficient in pantothenic acid. It required an external supply of 0.1-1.0 ppm thiamine, 0.01-0.1 ppm biotin, 10.0 ppm inositol, 0.10 ppm niacin and riboflavin for its optimum growth. H. polymorpha showed partial deficiency only in xanthine. P. polymorpha gave indications of partial deficiencies in thiamine and biotin. S. guttulata was completely deficient in biotin, and partially deficient in adenine sulphate. It required 0.01 ppm biotin for optimum growth. S chevalieri was completely deficient in pyridoxine and partially deficient in thiamine. It required 0.1 ppm pyridoxine for maximum growth. D. hansenii and B bruxellensis were auxoautotrophic for the various growth factors studied.

  10. Mapping Quantitative Trait Loci in Yeast.

    Science.gov (United States)

    Liti, Gianni; Warringer, Jonas; Blomberg, Anders

    2017-08-01

    Natural Saccharomyces strains isolated from the wild differ quantitatively in molecular and organismal phenotypes. Quantitative trait loci (QTL) mapping is a powerful approach for identifying sequence variants that alter gene function. In yeast, QTL mapping has been used in designed crosses to map functional polymorphisms. This approach, outlined here, is often the first step in understanding the molecular basis of quantitative traits. New large-scale sequencing surveys have the potential to directly associate genotypes with organismal phenotypes, providing a broader catalog of causative genetic variants. Additional analysis of intermediate phenotypes (e.g., RNA, protein, or metabolite levels) can produce a multilayered and integrated view of individual variation, producing a high-resolution view of the genotype-phenotype map. © 2017 Cold Spring Harbor Laboratory Press.

  11. Functional differences in yeast protein disulfide isomerases

    DEFF Research Database (Denmark)

    Nørgaard, P; Westphal, V; Tachibana, C

    2001-01-01

    PDI1 is the essential gene encoding protein disulfide isomerase in yeast. The Saccharomyces cerevisiae genome, however, contains four other nonessential genes with homology to PDI1: MPD1, MPD2, EUG1, and EPS1. We have investigated the effects of simultaneous deletions of these genes. In several...... cases, we found that the ability of the PDI1 homologues to restore viability to a pdi1-deleted strain when overexpressed was dependent on the presence of low endogenous levels of one or more of the other homologues. This shows that the homologues are not functionally interchangeable. In fact, Mpd1p...... was the only homologue capable of carrying out all the essential functions of Pdi1p. Furthermore, the presence of endogenous homologues with a CXXC motif in the thioredoxin-like domain is required for suppression of a pdi1 deletion by EUG1 (which contains two CXXS active site motifs). This underlines...

  12. Combinatorial Regulation in Yeast Transcription Networks

    Science.gov (United States)

    Li, Hao

    2006-03-01

    Yeast has evolved a complex network to regulate its transcriptional program in response to changes in environment. It is quite common that in response to an external stimulus, several transcription factors will be activated and they work in combinations to control different subsets of genes in the genome. We are interested in how the promoters of genes are designed to integrate signals from multiple transcription factors and what are the functional and evolutionary constraints. To answer how, we have developed a number of computational algorithms to systematically map the binding sites and target genes of transcription factors using sequence and gene expression data. To analyze the functional constraints, we have employed mechanistic models to study the dynamic behavior of genes regulated by multiple factors. We have also developed methods to trace the evolution of transcriptional networks via comparative analysis of multiple species.

  13. Import of ribosomal proteins into yeast mitochondria.

    Science.gov (United States)

    Woellhaf, Michael W; Hansen, Katja G; Garth, Christoph; Herrmann, Johannes M

    2014-12-01

    Mitochondrial ribosomes of baker's yeast contain at least 78 protein subunits. All but one of these proteins are nuclear-encoded, synthesized on cytosolic ribosomes, and imported into the matrix for biogenesis. The import of matrix proteins typically relies on N-terminal mitochondrial targeting sequences that form positively charged amphipathic helices. Interestingly, the N-terminal regions of many ribosomal proteins do not closely match the characteristics of matrix targeting sequences, suggesting that the import processes of these proteins might deviate to some extent from the general import route. So far, the biogenesis of only two ribosomal proteins, Mrpl32 and Mrp10, was studied experimentally and indeed showed surprising differences to the import of other preproteins. In this review article we summarize the current knowledge on the transport of proteins into the mitochondrial matrix, and thereby specifically focus on proteins of the mitochondrial ribosome.

  14. The impact of yeast fermentation on dough matrix properties.

    Science.gov (United States)

    Rezaei, Mohammad N; Jayaram, Vinay B; Verstrepen, Kevin J; Courtin, Christophe M

    2016-08-01

    Most studies on dough properties are performed on yeastless dough to exclude the complicating, time-dependent effect of yeast. Baker's yeast, however, impacts dough matrix properties during fermentation, probably through the production of primary (CO2 and ethanol) and secondary (glycerol, acetic acid and succinic acid) metabolites. The aim of this study is to obtain a better understanding of the changes in yeasted dough behavior introduced by fermentation, by investigating the impact of yeast fermentation on Farinograph dough consistency, dough spread, Kieffer rig dough extensibility and gluten agglomeration behavior in a fermented dough-batter gluten starch separation system. Results show that fermentation leads to a dough with less flow and lower extensibility that breaks more easily under stress and strain. The dough showed less elastic and more plastic deformation behavior. Gluten agglomerates were smaller for yeasted dough than for the unyeasted control. These changes probably have to be attributed to metabolites generated during fermentation. Indeed, organic acids and also ethanol in concentrations produced by yeast were previously shown to have similar effects in yeastless dough. These findings imply the high importance of yeast fermentation metabolites on dough matrix properties in industrial bread production. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  15. Yeast responses to stresses associated with industrial brewery handling.

    Science.gov (United States)

    Gibson, Brian R; Lawrence, Stephen J; Leclaire, Jessica P R; Powell, Chris D; Smart, Katherine A

    2007-09-01

    During brewery handling, production strains of yeast must respond to fluctuations in dissolved oxygen concentration, pH, osmolarity, ethanol concentration, nutrient supply and temperature. Fermentation performance of brewing yeast strains is dependent on their ability to adapt to these changes, particularly during batch brewery fermentation which involves the recycling (repitching) of a single yeast culture (slurry) over a number of fermentations (generations). Modern practices, such as the use of high-gravity worts and preparation of dried yeast for use as an inoculum, have increased the magnitude of the stresses to which the cell is subjected. The ability of yeast to respond effectively to these conditions is essential not only for beer production but also for maintaining the fermentation fitness of yeast for use in subsequent fermentations. During brewery handling, cells inhabit a complex environment and our understanding of stress responses under such conditions is limited. The advent of techniques capable of determining genomic and proteomic changes within the cell is likely vastly to improve our knowledge of yeast stress responses during industrial brewery handling.

  16. Identification and characterization of yeasts in sugarcane silages.

    Science.gov (United States)

    Avila, C L S; Bravo Martins, C E C; Schwan, R F

    2010-11-01

    To enumerate the micro-organisms and to identify the yeast species present during the ensilage of different sugarcane (Saccharum spp.) cultivars. Samples of sugarcane silage were collected at 10, 20, 30 and 40 days from the start of fermentation. Population levels of lactic acid bacteria (LAB), mesophilic facultative anaerobic (MFA) bacteria, filamentous fungi and yeasts were determined. Nine species of yeasts were classified according to traditional methods and confirmed using molecular techniques. LAB dominated the ensiling process of sugarcane, although yeasts were present at relatively high population levels throughout the whole fermentation period. The detected species of yeasts varied according to sugarcane cultivar and time of fermentation. Torulaspora delbrueckii was the predominant yeast, followed by Pichia anomala and Saccharomyces cerevisiae. Knowledge of the population of micro-organisms in general, and of yeasts in particular, present during the fermentation of sugarcane is of fundamental importance in the development of more effective ensiling processes. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  17. Genetic and physiological variants of yeast selected from palm wine.

    Science.gov (United States)

    Ezeronye, O U; Okerentugba, P O

    2001-01-01

    Genetic screening of 1200-palm wine yeasts lead to the selection of fourteen isolates with various genetic and physiological properties. Nine of the isolates were identified as Saccharamyces species, three as Candida species, one as Schizosaccharomyces species and one as Kluyveromyces species. Five of the isolates were wild type parents, two were respiratory deficient mutants (rho) and nine were auxotrophic mutants. Four isolates were heterozygous diploid (alphaa) and two were homozygous diploid (aa/alphaalpha) for the mating a mating types were further identified on mating with type loci. Four Mat alpha and four Mat a types were further identified on mating with standard haploid yeast strains. Forty-five percent sporulated on starvation medium producing tetrads. Fifty-two percent of the four-spored asci contained four viable spores. Maximum specific growth rate [micromax] of the fourteen isolates range from 0.13-0.26, five isolates were able to utilize exogenous nitrate for growth. Percentage alcohol production range between 5.8-8.8% for palm wine yeast, 8.5% for bakers' yeast and 10.4% for brewers yeast. The palm wine yeast were more tolerant to exogenous alcohol but had a low alcohol productivity. Hybridization enhanced alcohol productivity and tolerance in the palm wine yeasts.

  18. Potential Application of Yeast β-Glucans in Food Industry

    Directory of Open Access Journals (Sweden)

    Vesna Zechner-krpan

    2009-12-01

    Full Text Available Different β-glucans are found in a variety of natural sources such as bacteria, yeast, algae, mushrooms, barley and oat. They have potential use in medicine and pharmacy, food, cosmetic and chemical industries, in veterinary medicine and feed production. The use of different β-glucans in food industry and their main characteristics important for food production are described in this paper. This review focuses on beneficial properties and application of β-glucans isolated from different yeasts, especially those that are considered as waste from brewing industry. Spent brewer’s yeast, a by-product of beer production, could be used as a raw-material for isolation of β-glucan. In spite of the fact that large quantities of brewer’s yeast are used as a feedstuff , certain quantities are still treated as a liquid waste. β-Glucan is one of the compounds that can achieve a greater commercial value than the brewer’s yeast itself and maximize the total profitability of the brewing process. β-Glucan isolated from spent brewer’s yeast possesses properties that are benefi cial for food production. Therefore, the use of spent brewer’s yeast for isolation of β-glucan intended for food industry would represent a payable technological and economical choice for breweries.

  19. Rapid isolation of yeast genomic DNA: Bust n' Grab

    Directory of Open Access Journals (Sweden)

    Peterson Kenneth R

    2004-04-01

    Full Text Available Abstract Background Mutagenesis of yeast artificial chromosomes (YACs often requires analysis of large numbers of yeast clones to obtain correctly targeted mutants. Conventional ways to isolate yeast genomic DNA utilize either glass beads or enzymatic digestion to disrupt yeast cell wall. Using small glass beads is messy, whereas enzymatic digestion of the cells is expensive when many samples need to be analyzed. We sought to develop an easier and faster protocol than the existing methods for obtaining yeast genomic DNA from liquid cultures or colonies on plates. Results Repeated freeze-thawing of cells in a lysis buffer was used to disrupt the cells and release genomic DNA. Cell lysis was followed by extraction with chloroform and ethanol precipitation of DNA. Two hundred ng – 3 μg of genomic DNA could be isolated from a 1.5 ml overnight liquid culture or from a large colony. Samples were either resuspended directly in a restriction enzyme/RNase coctail mixture for Southern blot hybridization or used for several PCR reactions. We demonstrated the utility of this method by showing an analysis of yeast clones containing a mutagenized human β-globin locus YAC. Conclusion An efficient, inexpensive method for obtaining yeast genomic DNA from liquid cultures or directly from colonies was developed. This protocol circumvents the use of enzymes or glass beads, and therefore is cheaper and easier to perform when processing large numbers of samples.

  20. Yeast Biomass Production in Brewery's Spent Grains Hemicellulosic Hydrolyzate

    Science.gov (United States)

    Duarte, Luís C.; Carvalheiro, Florbela; Lopes, Sónia; Neves, Ines; Gírio, Francisco M.

    Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery's spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h-1, 0.61 g g-1, and 0.56 g 1-1 h-1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids.

  1. Yeast cell-based analysis of human lactate dehydrogenase isoforms.

    Science.gov (United States)

    Mohamed, Lulu Ahmed; Tachikawa, Hiroyuki; Gao, Xiao-Dong; Nakanishi, Hideki

    2015-12-01

    Human lactate dehydrogenase (LDH) has attracted attention as a potential target for cancer therapy and contraception. In this study, we reconstituted human lactic acid fermentation in Saccharomyces cerevisiae, with the goal of constructing a yeast cell-based LDH assay system. pdc null mutant yeast (mutated in the endogenous pyruvate decarboxylase genes) are unable to perform alcoholic fermentation; when grown in the presence of an electron transport chain inhibitor, pdc null strains exhibit a growth defect. We found that introduction of the human gene encoding LDHA complemented the pdc growth defect; this complementation depended on LDHA catalytic activity. Similarly, introduction of the human LDHC complemented the pdc growth defect, even though LDHC did not generate lactate at the levels seen with LDHA. In contrast, the human LDHB did not complement the yeast pdc null mutant, although LDHB did generate lactate in yeast cells. Expression of LDHB as a red fluorescent protein (RFP) fusion yielded blebs in yeast, whereas LDHA-RFP and LDHC-RFP fusion proteins exhibited cytosolic distribution. Thus, LDHB exhibits several unique features when expressed in yeast cells. Because yeast cells are amenable to genetic analysis and cell-based high-throughput screening, our pdc/LDH strains are expected to be of use for versatile analyses of human LDH. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  2. Measuring mitotic spindle dynamics in budding yeast

    Science.gov (United States)

    Plumb, Kemp

    In order to carry out its life cycle and produce viable progeny through cell division, a cell must successfully coordinate and execute a number of complex processes with high fidelity, in an environment dominated by thermal noise. One important example of such a process is the assembly and positioning of the mitotic spindle prior to chromosome segregation. The mitotic spindle is a modular structure composed of two spindle pole bodies, separated in space and spanned by filamentous proteins called microtubules, along which the genetic material of the cell is held. The spindle is responsible for alignment and subsequent segregation of chromosomes into two equal parts; proper spindle positioning and timing ensure that genetic material is appropriately divided amongst mother and daughter cells. In this thesis, I describe fluorescence confocal microscopy and automated image analysis algorithms, which I have used to observe and analyze the real space dynamics of the mitotic spindle in budding yeast. The software can locate structures in three spatial dimensions and track their movement in time. By selecting fluorescent proteins which specifically label the spindle poles and cell periphery, mitotic spindle dynamics have been measured in a coordinate system relevant to the cell division. I describe how I have characterised the accuracy and precision of the algorithms by simulating fluorescence data for both spindle poles and the budding yeast cell surface. In this thesis I also describe the construction of a microfluidic apparatus that allows for the measurement of long time-scale dynamics of individual cells and the development of a cell population. The tools developed in this thesis work will facilitate in-depth quantitative analysis of the non-equilibrium processes in living cells.

  3. Occurrence and function of yeasts in Asian indigenous fermented foods.

    Science.gov (United States)

    Aidoo, Kofi E; Nout, M J Rob; Sarkar, Prabir K

    2006-01-01

    In the Asian region, indigenous fermented foods are important in daily life. In many of these foods, yeasts are predominant and functional during the fermentation. The diversity of foods in which yeasts predominate ranges from leavened bread-like products such as nan and idli, to alcoholic beverages such as rice and palm wines, and condiments such as papads and soy sauce. Although several products are obtained by natural fermentation, the use of traditional starter cultures is widespread. This minireview focuses on the diversity and functionality of yeasts in these products, and on opportunities for research and development.

  4. PMAA-stabilized ferrofluid/chitosan/yeast composite for bioapplications

    Science.gov (United States)

    Baldikova, Eva; Prochazkova, Jitka; Stepanek, Miroslav; Hajduova, Jana; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

    2017-04-01

    A simple, one-pot process for the preparation of magnetically responsive yeast-based biocatalysts was developed. Saccharomyces cerevisiae, Candida utilis and Kluyveromyces lactis cells were successfully incorporated into chitosan gel magnetically modified with poly(methacrylic acid)-stabilized magnetic fluid (PMAA-FF) during its formation. Magnetic PMAA-FF/chitosan/yeast composites were efficiently employed for invert sugar production. The dependence of invertase activity on used yeast, amount of magnetic biocatalyst, agitation time and after reuse was studied in detail. The tested magnetic biocatalysts retained at least 69% of their initial activity after 8 reuse cycles.

  5. Production of yeast extract from whey using Kluyveromyces marxianus

    Directory of Open Access Journals (Sweden)

    Revillion Jean P. de Palma

    2003-01-01

    Full Text Available The yeast Kluyveromyces marxianus CBS 6556 was grown on whey to produce nucleotide-rich yeast extracts. Thermal treatments of cells at 35 or 50ºC for 15-30h resulted in yeast extracts containing about 20 g/L protein, with only the second treatment resulting in the presence of small amounts of RNA. In contrast, autolysis in buffered solution was the unique treatment that resulted in release of high amounts of intracellular RNA, being, therefore, the better procedure to produce 5'-nucletide rich extract with K. marxianus.

  6. Production of biopharmaceutical proteins by yeast: Advances through metabolic engineering

    DEFF Research Database (Denmark)

    Nielsen, Jens

    2013-01-01

    Production of recombinant proteins for use as pharmaceuticals, so-called biopharmaceuticals, is a multi-billion dollar industry. Many different cell factories are used for the production of biopharmaceuticals, but the yeast Saccharomyces cerevisiae is an important cell factory as it is used...... by yeast are human serum albumin, hepatitis vaccines and virus like particles used for vaccination against human papillomavirus. Here is given a brief overview of biopharmaceutical production by yeast and it is discussed how the secretory pathway can be engineered to ensure more efficient protein...... production. The involvement of directed metabolic engineering through the integration of tools from genetic engineering, systems biology and mathematical modeling, is also discussed....

  7. Evaluation of the Quantum II yeast identification system.

    OpenAIRE

    Kiehn, T E; Edwards, F F; Tom, D; LIEBERMAN, G; Bernard, E M; Armstrong, D.

    1985-01-01

    We compared three methods for identifying clinical yeast isolates: Abbott Quantum II, API 20C, and a modified BBL Minitek system. The API 20C and modified Minitek systems agreed on the identification of 243 of 245 yeasts (99.2%). The Quantum II system correctly identified 197 (80.4%), incorrectly identified 19 (7.8%), and did not identify 29 (11.8%) of the yeasts. Most of the misidentifications with the Quantum II occurred because assimilation or biochemical results were false-positive. Sixte...

  8. Mediated amperometry reveals different modes of yeast responses to sugars.

    Science.gov (United States)

    Garjonyte, Rasa; Melvydas, Vytautas; Malinauskas, Albertas

    2016-02-01

    Menadione-mediated amperometry at carbon paste electrodes modified with various yeasts (Saccharomyces cerevisiae, Candida pulcherrima, Pichia guilliermondii and Debaryomyces hansenii) was employed to monitor redox activity inside the yeast cells induced by glucose, fructose, sucrose, maltose or galactose. Continuous measurements revealed distinct modes (transient or gradually increasing) of the current development during the first 2 to 3 min after subjection to glucose, fructose and sucrose at electrodes containing S. cerevisiae and non-Saccharomyces strains. Different modes (increasing or decreasing) of the current development after yeast subjection to galactose at electrodes with S. cerevisiae or D. hansenii and at electrodes with C. pulcherrima and P. guilliermondii suggested different mechanisms of galactose assimilation.

  9. Media composition influences yeast one- and two-hybrid results

    Directory of Open Access Journals (Sweden)

    Gonzalez Kim L

    2011-08-01

    Full Text Available Abstract Although yeast two-hybrid experiments are commonly used to identify protein interactions, the frequent occurrence of false negatives and false positives hampers data interpretation. Using both yeast one-hybrid and two-hybrid experiments, we have identified potential sources of these problems: the media preparation protocol and the source of the yeast nitrogen base may not only impact signal range but also effect whether a result appears positive or negative. While altering media preparation may optimize signal differences for individual experiments, media preparation must be reported in detail to replicate studies and accurately compare results from different experiments.

  10. Yeasts isolated from clinical samples of AIDS patients

    Directory of Open Access Journals (Sweden)

    Neves Rejane Pereira

    2002-01-01

    Full Text Available In order to investigate yeasts in oropharyngeal secretion, urine, sputum and inguinal scales from AIDS patients, clinical samples were collected from one hundred patients interned in the Infectious and Parasitic Diseases Sector of the Hospital das Clínicas of the Universidade Federal de Pernambuco and in Hospital Universitário Osvaldo Cruz of the Universidade de Pernambuco. Yeasts were isolated from seventy-two out of one hundred and eight clinical samples. The isolated yeasts were: Candida albicans (sixty-two isolates, Candida tropicalis (four isolates, Candida glabrata (two isolates, Candida parapsilosis (two isolates, Candida krusei (one isolate and Trichosporon pullulans (one isolate.

  11. Yeast biotechnology: teaching the old dog new tricks

    Science.gov (United States)

    2014-01-01

    Yeasts are regarded as the first microorganisms used by humans to process food and alcoholic beverages. The technology developed out of these ancient processes has been the basis for modern industrial biotechnology. Yeast biotechnology has gained great interest again in the last decades. Joining the potentials of genomics, metabolic engineering, systems and synthetic biology enables the production of numerous valuable products of primary and secondary metabolism, technical enzymes and biopharmaceutical proteins. An overview of emerging and established substrates and products of yeast biotechnology is provided and discussed in the light of the recent literature. PMID:24602262

  12. Metabolic engineering of yeast for fermentative production of flavonoids

    DEFF Research Database (Denmark)

    Rodriguez Prado, Edith Angelica; Strucko, Tomas; Stahlhut, Steen Gustav

    2017-01-01

    Yeast Saccharomyces cerevisiae was engineered for de novo production of six different flavonoids (naringenin, liquiritigenin, kaempferol, resokaempferol, quercetin, and fisetin) directly from glucose, without supplementation of expensive intermediates. This required reconstruction of long...... biosynthetic pathways, comprising up to eight heterologous genes from plants. The obtained titers of kaempferol 26.57±2.66mgL-1 and quercetin 20.38±2.57mgL-1 exceed the previously reported titers in yeast. This is also the first report of de novo biosynthesis of resokaempferol and fisetin in yeast. The work...

  13. Transcription reactions of yeast RNA polymerase II in vitro

    Institute of Scientific and Technical Information of China (English)

    赵宇; 敖世洲

    1995-01-01

    The transcription reactions in vitro of yeast ADHl and PHO5 gene promoters are investigated by means of a yeast crude nuclear extract. Using specific RNA probes, the transcription products of these 2 promoters have been first obtained. A low concentration of α-amanitin is highly inhibitory. The transcription of the PHO5 gene was initiated in vitro at or near the sites used in vim. The transcription products increase with the amount of the template and reach the maximum at certain concentrations of the template. The deletion of the yeast promoter sequences abolishes the reaction.

  14. Characterization of Septin Ultrastructure in Budding Yeast Using Electron Tomography

    Science.gov (United States)

    Bertin, Aurélie; Nogales, Eva

    2015-01-01

    Summary Septins are essential for the completion of cytokinesis. In budding yeast, Saccharomyces cerevisiae, septins are located at the bud neck during mitosis and are closely connected to the inner plasma membrane. In vitro, yeast septins have been shown to self-assemble into a variety of filamentous structures, including rods, paired filaments, bundles and rings [1–3]. Using electron tomography of freeze-substituted section and cryo-electron tomography of frozen sections, we determined the three dimensional organization of the septin cytoskeleton in dividing budding yeast with molecular resolution [4,5]. Here we describe the detailed procedures used for our characterization of the septin cellular ultrastructure. PMID:26519309

  15. Estrogen Receptor Agonists and Antagonists in the Yeast Estrogen Bioassay.

    Science.gov (United States)

    Wang, Si; Bovee, Toine F H

    2016-01-01

    Cell-based bioassays can be used to predict the eventual biological activity of a substance on a living organism. In vitro reporter gene bioassays are based on recombinant vertebrate cell lines or yeast strains and especially the latter are easy-to-handle, cheap, and fast. Moreover, yeast cells do not express estrogen, androgen, progesterone or glucocorticoid receptors, and are thus powerful tools in the development of specific reporter gene systems that are devoid of crosstalk from other hormone pathways. This chapter describes our experience with an in-house developed RIKILT yeast estrogen bioassay for testing estrogen receptor agonists and antagonists, focusing on the applicability of the latter.

  16. Brettanomyces bruxellensis yeasts: impact on wine and winemaking.

    Science.gov (United States)

    Agnolucci, Monica; Tirelli, Antonio; Cocolin, Luca; Toffanin, Annita

    2017-09-21

    Yeasts belonging to the Brettanomyces/Dekkera genus are non-conventional yeasts, which affect winemaking by causing wine spoilage all over the world. This mini-review focuses on recent results concerning the presence of Brettanomyces bruxellensis throughout the wine processing chain. Here, culture-dependent and independent methods to detect this yeast on grapes and at the very early stage of wine production are encompassed. Chemical, physical and biological tools, devised for the prevention and control of such a detrimental species during winemaking are also presented. Finally, the mini-review identifies future research areas relevant to the improvement of wine safety and sensory profiles.

  17. The manometric determination of thiamine pyrophosphate and the inhibition of the acid yeast phosphatase

    NARCIS (Netherlands)

    Steyn-Parvé, Elizabeth P.

    1962-01-01

    Sodium molybdate is a powerful inhibitor of the acid yeast phosphatase in both fresh baker's yeast and dried brewer's yeast, provided that the yeast is suspended in a suitable buffer. It displays no action in citrate or phosphate buffers, but is active in acetate or maleate buffers, both at the opti

  18. Yeasts for Global Happiness: report of the 14th International Congress on Yeasts (ICY14) held in Awaji Island.

    Science.gov (United States)

    Watanabe, Daisuke; Takagi, Hiroshi

    2017-02-01

    The 14th International Congress on Yeasts (ICY14) was held at Awaji Yumebutai International Conference Center (Awaji, Hyogo) in Japan from 11 to 15 September 2016. The main slogan of ICY14 was 'Yeasts for Global Happiness', which enabled us to acknowledge the high-potential usefulness of yeasts contributing to the global happiness in terms of food/beverage, health/medicine and energy/environment industries, as well as to basic biosciences. In addition, two more concepts were introduced: 'from Japan to the world' and 'from senior to junior'. As it was the first ICY meeting held in Japan or other Asian countries, ICY14 provided a good opportunity to widely spread the great achievements by Japanese and Asian yeast researchers, such as those by the 2016 Nobel Laureate Dr. Yoshinori Ohsumi, and also, to convey the fun and importance of yeasts to the next generation of researchers from Asia and all over the world. As a result, a total of 426 yeast lovers from 42 countries (225 overseas and 201 domestic participants) with different generations attended ICY14 to share the latest knowledge of a wide range of yeast research fields and to join active and constructive scientific discussions. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

  19. Differential Adsorption of Ochratoxin A and Anthocyanins by Inactivated Yeasts and Yeast Cell Walls during Simulation of Wine Aging

    Directory of Open Access Journals (Sweden)

    Leonardo Petruzzi

    2015-10-01

    Full Text Available The adsorption of ochratoxin A (OTA by yeasts is a promising approach for the decontamination of musts and wines, but some potential competitive or interactive phenomena between mycotoxin, yeast cells, and anthocyanins might modify the intensity of the phenomenon. The aim of this study was to examine OTA adsorption by two strains of Saccharomyces cerevisiae (the wild strain W13, and the commercial isolate BM45, previously inactivated by heat, and a yeast cell wall preparation. Experiments were conducted using Nero di Troia red wine contaminated with 2 μg/L OTA and supplemented with yeast biomass (20 g/L. The samples were analyzed periodically to assess mycotoxin concentration, chromatic characteristics, and total anthocyanins over 84 days of aging. Yeast cell walls revealed the highest OTA-adsorption in comparison to thermally-inactivated cells (50% vs. 43% toxin reduction, whilst no significant differences were found for the amount of adsorbed anthocyanins in OTA-contaminated and control wines. OTA and anthocyanins adsorption were not competitive phenomena. Unfortunately, the addition of yeast cells to wine could cause color loss; therefore, yeast selection should also focus on this trait to select the best strain.

  20. Construction of a large synthetic human Fab antibody library on yeast cell surface by optimized yeast mating.

    Science.gov (United States)

    Baek, Du-San; Kim, Yong-Sung

    2014-03-28

    Yeast surface-displayed antibody libraries provide an efficient and quantitative screening resource for given antigens, but suffer from typically modest library sizes owing to low yeast transformation efficiency. Yeast mating is an attractive method for overcoming the limit of yeast transformation to construct a large, combinatorial antibody library, but the optimal conditions have not been reported. Here, we report a large synthetic human Fab (antigen binding fragment) yeast surface-displayed library generated by stepwise optimization of yeast mating conditions. We first constructed HC (heavy chain) and LC (light chain) libraries, where all of the six CDRs (complementarity-determining regions) of the variable domains were diversified mimicking the human germline antibody repertoires by degenerate codons, onto single frameworks of VH3-23 and Vkappa1-16 germline sequences, in two haploid cells of opposite mating types. Yeast mating conditions were optimized in the order of cell density, media pH, and cell growth phase, yielding a mating efficiency of ~58% between the two haploid cells carrying HC and LC libraries. We constructed two combinatorial Fab libraries with CDR-H3 of 9 or 11 residues in length with colony diversities of more than 10(9) by one round of yeast mating between the two haploid HC and LC libraries, with modest diversity sizes of ~10(7). The synthetic human Fab yeast-displayed libraries exhibited relative amino acid compositions in each position of the six CDRs that were very similar to those of the designed repertoires, suggesting that they are a promising source for human Fab antibody screening.

  1. Oxygen Consumption by Postfermentation Wine Yeast Lees: Factors Affecting Its Rate and Extent under Oenological Conditions

    OpenAIRE

    Schneider, Volker; Müller, Jonas; Schmidt, Dominik

    2016-01-01

    Postfermentation wine yeast lees show antioxidant properties based on their ability to consume dissolved oxygen. The oxygen consumption capacity of suspended yeast lees obtained after fermentations with six commercial active dry yeast strains was investigated in model, white and red wines using fluorescence-based oxygen sensors operating in a nondestructive way. In model solution, the oxygen consumption rate of yeast lees was shown to depend on their amount, yeast strain, sulfur dioxide and t...

  2. 21 CFR 172.898 - Bakers yeast glycan.

    Science.gov (United States)

    2010-04-01

    ...) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3... used or intended for use in the following foods when standards of identity established under...

  3. [Overexpression of FKS1 to improve yeast autolysis-stress].

    Science.gov (United States)

    Li, Jia; Wang, Jinjing; Li, Qi

    2015-09-01

    With the development of high gravity brewing, yeast cells are exposed to multiple brewing-associated stresses, such as increased osmotic pressure, enhanced alcohol concentration and nutritional imbalance. These will speed up yeast autolysis, which seriously influence beer flavor and quality. To increase yeast anti-autolytic ability, FKS1 overexpression strain was constructed by 18S rDNA. The concentration of β-1,3-glucan of overexpression strain was 62% higher than that of wild type strain. Meantime, FKS1 overexpression strain increased anti-stress ability at 8% ethanol, 0.4 mol/L NaCl and starvation stress. Under simulated autolysis, FKS1 showed good anti-autolytic ability by slower autolysis. These results confirms the potential of FKS1 overexpression to tackle yeast autolysis in high-gravity brewing.

  4. Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts.

    Science.gov (United States)

    Gallone, Brigida; Steensels, Jan; Prahl, Troels; Soriaga, Leah; Saels, Veerle; Herrera-Malaver, Beatriz; Merlevede, Adriaan; Roncoroni, Miguel; Voordeckers, Karin; Miraglia, Loren; Teiling, Clotilde; Steffy, Brian; Taylor, Maryann; Schwartz, Ariel; Richardson, Toby; White, Christopher; Baele, Guy; Maere, Steven; Verstrepen, Kevin J

    2016-09-01

    Whereas domestication of livestock, pets, and crops is well documented, it is still unclear to what extent microbes associated with the production of food have also undergone human selection and where the plethora of industrial strains originates from. Here, we present the genomes and phenomes of 157 industrial Saccharomyces cerevisiae yeasts. Our analyses reveal that today's industrial yeasts can be divided into five sublineages that are genetically and phenotypically separated from wild strains and originate from only a few ancestors through complex patterns of domestication and local divergence. Large-scale phenotyping and genome analysis further show strong industry-specific selection for stress tolerance, sugar utilization, and flavor production, while the sexual cycle and other phenotypes related to survival in nature show decay, particularly in beer yeasts. Together, these results shed light on the origins, evolutionary history, and phenotypic diversity of industrial yeasts and provide a resource for further selection of superior strains. PAPERCLIP.

  5. Psychrophilic yeasts and their biotechnological applications - A review

    African Journals Online (AJOL)

    SAM

    2014-05-28

    May 28, 2014 ... Psychrophilic yeast produces cold-active enzymes having numerous applications in .... group of enzymes that hydrolyze the pectic substances present in .... antarctica for the preparation of optically active alcohols has been ...

  6. Biodiversity of brewery yeast strains and their fermentative activities.

    Science.gov (United States)

    Berlowska, Joanna; Kregiel, Dorota; Rajkowska, Katarzyna

    2015-01-01

    We investigated the genetic, biochemical, fermentative and physiological characteristics of brewery yeast strains and performed a hierarchical cluster analysis to evaluate their similarity. We used five different ale and lager yeast strains, originating from different European breweries and deposited at the National Collection of Yeast Cultures (UK). Ale and lager strains exhibited different genomic properties, but their assimilation profiles and pyruvate decarboxylase activities corresponded to their species classifications. The activity of another enzyme, succinate dehydrogenase, varied between different brewing strains. Our results confirmed that ATP and glycogen content, and the activity of the key metabolic enzymes succinate dehydrogenase and pyruvate decarboxylase, may be good general indicators of cell viability. However, the genetic properties, physiology and fermentation capacity of different brewery yeasts are unique to individual strains.

  7. A molecular mechanism of chronological aging in yeast

    National Research Council Canada - National Science Library

    Burtner, Christopher R; Murakami, Christopher J; Kennedy, Brian K; Kaeberlein, Matt

    2009-01-01

    ....  Dietary restriction extends the life span of many organisms, including yeast, and efforts are underway to understand the biochemical and genetic pathways that regulate this life span extension in model organisms...

  8. Isolation and molecular genetic characterization of a yeast strain ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-18

    May 18, 2009 ... Key words: Yeast, PAHs pollutant, 26S rRNA gene. INTRODUCTION. Polycyclic .... sole source of carbon and energy. Although all the strains .... Calculated mass balance of PAHs in liqued culture (n = 3). PAH. No. of rings.

  9. RAPD analysis : a rapid technique for differentation of spoilage yeasts

    NARCIS (Netherlands)

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

    1994-01-01

    Techniques for the identification of the spoilage yeasts Saccharomyces cerevisiae and members of the Zygosaccharomyces genus from food and beverages sources were evaluated. The use of identification systems based on physiological characteristics resulted often in incomplete identification or misiden

  10. A contribution to the knowledge of yeasts in Olsztyn lakes

    Directory of Open Access Journals (Sweden)

    Maria Dynowska

    2014-08-01

    Full Text Available Yeasts species have been analysed from Skanda and Kartowo Lakes. Their presence reflects poor sanitary stale of the lakes, with Skanda Lake particulary affected by the process of eutrophication.

  11. Tools for genetic engineering of the yeast Hansenula polymorpha

    NARCIS (Netherlands)

    Saraya, Ruchi; Gidijala, Loknath; Veenhuis, Marten; van der Klei, Ida J; Mapelli, Valeria

    2014-01-01

    Hansenula polymorpha is a methylotrophic yeast species that has favorable properties for heterologous protein production and metabolic engineering. It provides an attractive expression platform with the capability to secrete high levels of commercially important proteins. Over the past few years

  12. Effects of Selenium Yeast on Blood Glucose and Antioxidant ...

    African Journals Online (AJOL)

    olayemitoyin

    inducer of diabetes mellitus. Keywords: Cholesterol diet; Diabetes Mellitus; Selenium yeast; SOD; CAT; GPx ... studies aimed at examining the importance of selenium status in the .... These corroborating epidemiological reports suggest that ...

  13. New insight into translation during yeast programmed cell death

    OpenAIRE

    Silva, Maria Alexandra Oliveira da

    2012-01-01

    Tese de doutoramento em Ciências da Saúde Global mRNA translation impairment has been described during the course of apoptosis in both mammalian and yeast. Nevertheless, the molecular pathways modulating translation during different scenarios of yeast apoptosis are still largely unexplored. Here we show by polysome profile analysis an impairment in capdependent translation initiation, correlated with alterations in translation machinery, such as the decrease in eIF4A levels ...

  14. Opportunistic yeast infections: candidiasis, cryptococcosis, trichosporonosis and geotrichosis.

    Science.gov (United States)

    Vázquez-González, Denisse; Perusquía-Ortiz, Ana María; Hundeiker, Max; Bonifaz, Alexandro

    2013-05-01

    Opportunistic yeast infections are diseases caused by fungi which normally are saprophytic and do not cause disease in humans or animals. The prevalence of these diseases has been increasing due to immunosuppressive, corticosteroid, and long-term antibiotic treatment following organ transplantation or after serious metabolic, hematological, or immunological diseases. We review epidemiological, clinical, diagnostic, and therapeutic aspects of the four "big" opportunistic yeast infections: candidiasis, cryptococcosis, trichosporonosis, and geotrichosis.

  15. Bioprospection of yeasts as biocontrol agents against phytopathogenic molds

    Directory of Open Access Journals (Sweden)

    Márcia Maria Rosa-Magri

    2011-02-01

    Full Text Available Yeasts isolated from sugar cane and maize rhizosphere, leaves and stalks were screened against the phytopathogenic molds Colletotrichum sublineolum and Colletotrichum graminicola, both causal agents of the anthracnose disease in sorghum and maize, respectively. Strains identified as Torulaspora globosa and Candida intermedia were able to inhibit the mold growth, with the first species also exhibiting killer activity. No previous report on the application and potentiality of these yeasts as biocontrol agents were found neither the killer phenotype in Torulaspora globosa.

  16. Bioprospection of yeasts as biocontrol agents against phytopathogenic molds

    OpenAIRE

    Márcia Maria Rosa-Magri; Sâmia Maria Tauk-Tornisielo; Sandra Regina Ceccato-Antonini

    2011-01-01

    Yeasts isolated from sugar cane and maize rhizosphere, leaves and stalks were screened against the phytopathogenic molds Colletotrichum sublineolum and Colletotrichum graminicola, both causal agents of the anthracnose disease in sorghum and maize, respectively. Strains identified as Torulaspora globosa and Candida intermedia were able to inhibit the mold growth, with the first species also exhibiting killer activity. No previous report on the application and potentiality of these yeasts as bi...

  17. Bacterial and yeast counts in Brazilian commodities and spices

    Directory of Open Access Journals (Sweden)

    Freire Francisco das Chagas Oliveira

    2002-01-01

    Full Text Available A total of thirteen genera of bacteria and two genera of yeasts were detected in surface sterilized and unsterilized Brazilian commodities and spices such as cashew kernels, Brazil nut kernels, black and white pepper. The genus Bacillus with eight species was by far the most common. The yeasts isolated were Pichia sp., P. guillermondii and Rhodotorula sp. Bacillus cereus, Salmonella typhimurium and Staphylococcus aureus were detected in cashew and Brazil nut kernels.

  18. Prevalence of Yeasts in English Full Blood Mares

    OpenAIRE

    Różański, Paweł; Ślaska, Brygida; Różańska, Dorota

    2013-01-01

    The aim of the study was a quantitative and qualitative analysis of microflora, presentation of current data about prevalence of the microflora on the skin and mucous membranes, and determination of its possible effect on reproduction of English full blood horses bred in Poland. The material for analyses was sampled from the skin and mucous membranes (385 samples) of 55 English full blood mares. Taking into account reproduction traits, the mares were classified into three groups. Six yeast-li...

  19. Pheromone communication in the fission yeast Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Nielsen, O; Davey, William John; Nielsen, Olaf

    1995-01-01

    Conjugation between two haploid yeast cells is generally controlled by the reciprocal action of diffusible mating pheromones, cells of each mating type releasing pheromones that induce mating-specific changes in cells of the opposite type. Recent studies into pheromone signalling in the fission y...... yeast Schizosaccharomyces pombe have revealed significant parallels with processes in higher eukaryotes and could provide the opportunity for investigating communication in an organism that is amenable to both biochemical and genetic manipulation....

  20. [Studies on the assimilation of inorganic selenium by yeast].

    Science.gov (United States)

    Xie, L; Ouyang, Z; Xie, X

    1990-02-01

    In the process of assimilation of inorganic selenium by yeast to the organic-selenium, some rules on the relation of the kinds of culture medium, concentration of sodium selenite and methionine to the total selenium and selenomethionine content in the yeast formed have been found; and a new, accurate procedure--modified acid hydrolysis-ion exchange chromatography for determining the content of seleno-amino acid in biological materials has been established.

  1. Spent yeast as natural source of functional food additives

    Science.gov (United States)

    Rakowska, Rita; Sadowska, Anna; Dybkowska, Ewa; Świderski, Franciszek

    Spent yeasts are by-products arising from beer and wine production which over many years have been chiefly used as feed additives for livestock. They contain many valuable and bioactive substances which has thereby generated much interest in their exploitation. Up till now, the main products obtained from beer-brewing yeasts are β-glucans and yeast extracts. Other like foodstuffs include dried brewer’s yeast, where this is dried and the bitterness removed to be fit for human consumption as well as mannan-oligosaccharides hitherto used in the feed industry. β-glucans constitute the building blocks of yeast cell walls and can thus be used in human nutrition as dietary supplements or serving as food additives in functional foods. β-glucans products obtained via post-fermentation of beer also exhibit a high and multi-faceted biological activity where they improve the blood’s lipid profile, enhance immunological status and have both prebiotic and anti-oxidant properties. Yeast extracts are currently being used more and more to enhance flavour in foodstuffs, particularly for meat and its products. Depending on how autolysis is carried out, it is possible to design extracts of various meat flavours characteristic of specific meats. Many different flavour profiles can be created which may be additionally increased in combination with vegetable extracts. Within the food market, yeast extracts can appear in various guises such as liquids, pastes or powders. They all contain significant amounts of glutamic acid, 5’-GMP and 5’-IMP nucleotides together with various amino acids and peptides that act synergistically for enhancing the flavour of foodstuff products. Recent studies have demonstrated additional benefits of yeast extracts as valuable sources of amino acids and peptides which can be used in functional foods and dietary supplements. These products possess GRAS status (Generally Recognised As Safe) which thereby also adds further as to why they should be used

  2. Occurrence and Diversity of Marine Yeasts in Antarctica Environments

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue; HUA Mingxia; SONG Chunli; CHI Zhenming

    2012-01-01

    A total of 28 yeast strains were obtained from the sea sediment of Antarctica.According to the results of routine identification and molecular characterization,the strains belonged to species of Yarrowia lipolytica,Debaryomyces hansenii,Rhodotorula slooffiae,Rhodotorula mucilaginosa,Sporidiobolus salmonicolor,Aureobasidium pullulans,Mrakia frigida and Guehomyces pullulans,respectively.The Antarctica yeasts have wide potential applications in biotechnology,for some of them can produce β-galactosidase and killer toxins.

  3. Prion Diseases of Yeast: Amyloid Structure and Biology

    OpenAIRE

    Reed B Wickner; Edskes, Herman K.; Kryndushkin, Dmitry; McGlinchey, Ryan; Bateman, David; Kelly, Amy

    2011-01-01

    Prion “variants” or “strains” are prions with the identical protein sequence, but different characteristics of the prion infection: e.g. different incubation period for scrapie strains or different phenotype intensity for yeast prion variants. We have shown that infectious amyloids of the yeast prions [PSI+], [URE3] and [PIN+] each have an in-register parallel β-sheet architecture. Moreover, we have pointed out that this amyloid architecture can explain how one protein can faithfully transmit...

  4. Occurrence and diversity of marine yeasts in Antarctica environments

    Science.gov (United States)

    Zhang, Xue; Hua, Mingxia; Song, Chunli; Chi, Zhenming

    2012-03-01

    A total of 28 yeast strains were obtained from the sea sediment of Antarctica. According to the results of routine identification and molecular characterization, the strains belonged to species of Yarrowia lipolytica, Debaryomyces hansenii, Rhodotorula slooffiae, Rhodotorula mucilaginosa, Sporidiobolus salmonicolor, Aureobasidium pullulans, Mrakia frigida and Guehomyces pullulans, respectively. The Antarctica yeasts have wide potential applications in biotechnology, for some of them can produce β-galactosidase and killer toxins.

  5. Yeast expression proteomics by high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Walther, Tobias C; Olsen, Jesper Velgaard; Mann, Matthias

    2010-01-01

    -translational controls contribute majorly to regulation of protein abundance, for example in heat shock stress response. The development of new sample preparation methods, high-resolution mass spectrometry and novel bioinfomatic tools close this gap and allow the global quantitation of the yeast proteome under different...... conditions. Here, we provide background information on proteomics by mass-spectrometry and describe the practice of a comprehensive yeast proteome analysis....

  6. Core Data of Yeast Interacting Proteins Database (Annotation Updated Version) - Yeast Interacting Proteins Database | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available nteractions are required. Several sources including YPD (Yeast Proteome Database, Costanzo, M. C., Hogan, J....erse direction. *1 The yeast proteome database (YPD) and Caenorhabditis elegans proteome database (WormPD): comprehensive resources

  7. The influence of exogenous nutrients on the abundance of yeasts on the phylloplane of turfgrass.

    Science.gov (United States)

    Nix-Stohr, Shannon; Burpee, Leon L; Buck, James W

    2008-01-01

    Four experiments were conducted to assess the effect of foliar applications of various nutrient solutions on the phylloplane yeast community of tall fescue (Festuca arundinacea Schreb.). In the first three experiments, increasing concentrations of sucrose (2-16%), yeast extract (0.5-2.5%), and sucrose plus yeast extract (2.5-18.5% total) were applied and the yeast colony forming units (cfu) enumerated 14 h later by dilution plating. Significant positive linear relationships were observed between the number of yeast cfu and applications of both yeast extract and sucrose plus yeast extract. Foliar applications of sucrose alone had no significant effect on yeast community abundance, indicating that phylloplane yeasts of turfgrass are not limited by the amount or availability of carbohydrates. In the fourth experiment, five different solutions were applied to tall fescue to investigate the response of the yeast community to organic and inorganic nitrogen sources. Tryptone or yeast extract, both with considerable amino acid composition, significantly increased the yeast population, while yeast nitrogen base (with or without amino acids) and ammonium sulfate had no affect on yeast abundance. These results suggest that organic nitrogen stimulate yeast community growth and development on the phylloplane of tall fescue, while carbohydrates, inorganic nitrogen, and non-nitrogenous nutrients have little positive effect.

  8. The Fermentative and Aromatic Ability of Kloeckera and Hanseniaspora Yeasts

    Science.gov (United States)

    Díaz-Montaño, Dulce M.; de Jesús Ramírez Córdova, J.

    Spontaneous alcoholic fermentation from grape, agave and others musts into an alcoholic beverage is usually characterized by the presence of several non-Saccharomyces yeasts. These genera yeasts are dominant in the early stages of the alcoholic fermentation. However the genera Hanseniaspora and Kloeckera may survive at a significant level during fermentation and can influence the chemical composition of the beverage. Several strains belonging to the species Kloeckera api-culata and Hanseniaspora guilliermondii have been extensively studied in relation to the formation of some metabolic compounds affecting the bouquet of the final product. Indeed some apiculate yeast showed positive oenological properties and their use in the alcoholic fermentations has been suggested to enhance the aroma and flavor profiles. The non- Saccharomyces yeasts have the capability to produce and secrete enzymes in the medium, such as β -glucosidases, which release monoterpenes derived from their glycosylated form. These compounds contribute to the higher fruit-like characteristic of final product. This chapter reviews metabolic activity of Kloeckera and Hanseniaspora yeasts in several aspects: fermentative capability, aromatic compounds production and transformation of aromatic precursor present in the must, also covers the molecular methods for identifying of the yeast

  9. Production of intracellular enzymes by enzymatic treatment of yeast

    Energy Technology Data Exchange (ETDEWEB)

    Zomer, E.; Er-El, Z.; Rokem, J.S.

    1987-01-01

    Enzymatic extraction of intracellular enzymes from various yeasts by glucanase was investigated. Favourable conditions for lysis and release of intracellular enzymes were established. The effects of yeast concentration, growth phase of yeast, storage temperature and pretreatment of yeast were studied. The yeasts investigated can be divided into two groups. The first, Kluyveromyces lactis, Saccharomyces cerevisiae, Saccharomyces oviformis, Torulopsis glabrata, Hansenula polymorpha and local bakers' yeast, lysed relatively easily (70-80% of the cells), especially when cells from the logarithmic growth phase were treated. The second, Candida utilis and Candida vini, were more susceptible to lysis (40-50%) when cells were taken from the stationary phase. Release of two enzymes, glycerol kinase from Candida utilis grown on glycerol and formate dehydrogenase from Torulopsis glabrata grown on methanol was examined. The highest specific activities were obtained by incubating the cells with glucanase for 1.5 hours at 37 degrees C. Inactivation of the released enzyme was relatively low. After 12 hours of enzymatic treatment at 28 degrees C glycerol kinase maintained about 50%, and formate dehydrogenase over 80%, of the original activities. (Refs. 12).

  10. Psychrophilic yeasts in glacial environments of Alpine glaciers.

    Science.gov (United States)

    Turchetti, Benedetta; Buzzini, Pietro; Goretti, Marta; Branda, Eva; Diolaiuti, Guglielmina; D'Agata, Carlo; Smiraglia, Claudio; Vaughan-Martini, Ann

    2008-01-01

    The presence of psychrophilic yeasts in supra- and subglacial sediments, ice and meltwater collected from two glaciers of the Italian Alps (Forni and Sforzellina-Ortles-Cevedale group) was investigated. After incubation at 4 degrees C, subglacial sediments contained from 1.3 x 10(3) to 9.6 x 10(3) CFU of yeasts g(-1). The number of yeast cells in supraglacial sediments was c. 10-100-fold lower. A significant proportion of isolated yeasts exhibited one or more extracellular enzymatic activities (starch-degrading, lipolytic, esterolytic, proteolytic and pectinolytic activity) at 4 degrees C. Selected isolates were able to grow at 2 degrees C under laboratory-simulated in situ conditions. In all, 106 isolated yeasts were identified by MSP-PCR fingerprinting and 26S rRNA gene sequencing of the D1/D2 region as belonging to 10 species: Aureobasidium pullulans, Cryptococcus gilvescens (over 50% of the total), Cryptococcus terricolus, Mrakia gelida, Naganishia globosa, Rhodotorula glacialis, Rhodotorula psychrophenolica, Rhodotorula bacarum, Rhodotorula creatinivora and Rhodotorula laryngis. Four strains, all belonging to a new yeast species, yet to be described, were also isolated.

  11. Determination of Yeasts Antimicrobial Activity in Milk and Meat Products

    Directory of Open Access Journals (Sweden)

    L.B. Roostita

    2011-12-01

    Full Text Available The research was arranged to isolate yeasts from livestock products and then the yeasts antimicrobial activity was tested towards putrefaction and pathogenic bacteria. Yeasts isolated from livestock products using Malt Extract Agar (MEA, the total yeasts population counted with using total plate count method, antimicrobial activity tested using diffusion methods against Pseudomonas aerugenes, Staphylococcus aureus and Escherichia coli and then the chosen isolate identified with using 18s RNA method. The results have shown that the total yeasts population on pasteurized cow’s milk were 1.2×106 cfu/g, fruit yoghurt 5.4×106 cfu/g, lamb meat 1×105 cfu/g, beef 1×105 cfu/g and beef sausages 1×106 cfu/g total yeasts population. Fruit yoghurt isolate shown the best antimicrobial activity with 35 mm clear zone diameter against Pseudomonas aerugenes, 8 mm clear zone diameter against Staphylococcus aureus and 10 mm clear zone diameter against Escherichia coli. The 18 s RNA test shown that fruit yoghurt isolate was 100% (FR3-F primer and 99% (FR3-R primer identical with Candida parapsilosis.

  12. Investigation of zinc biosorption by brewer's yeast cells

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    Dodić Siniša N.

    2005-01-01

    Full Text Available The highest amount of zinc (= 90% is bound after 3 hrs of contact at low initial (total concentrations of zinc in suspension of yeast, 10-100 mg/l at 10-30°C. The equilibrium between bound and free zinc ions is established after 6 hrs of contact time, independently on the total zinc concentration in yeast milk. No bigger changes of content of zinc bound to brewer's yeast cells was determined at temperatures 10°C and 30°C. 40% of bound zinc in the equilibrium state is bound during the first 15 min of contact of zinc ions and brewer's yeast cells at all initial (total zinc concentrations in suspension of yeast both at 10°C and 30°C. The "KEKAM" equation can be used for the description of kinetics of zinc biosorption by waste brewer's yeast cells, for the ranges of zinc concentration 10-100 mg/l at 30°C (mean correlation coefficient 0,96 and 60,0-100 mg/l at 10°C (mean correlation coefficient 0,95.

  13. The yeast deletion collection: a decade of functional genomics.

    Science.gov (United States)

    Giaever, Guri; Nislow, Corey

    2014-06-01

    The yeast deletion collections comprise >21,000 mutant strains that carry precise start-to-stop deletions of ∼6000 open reading frames. This collection includes heterozygous and homozygous diploids, and haploids of both MAT A: and MATα mating types. The yeast deletion collection, or yeast knockout (YKO) set, represents the first and only complete, systematically constructed deletion collection available for any organism. Conceived during the Saccharomyces cerevisiae sequencing project, work on the project began in 1998 and was completed in 2002. The YKO strains have been used in numerous laboratories in >1000 genome-wide screens. This landmark genome project has inspired development of numerous genome-wide technologies in organisms from yeast to man. Notable spinoff technologies include synthetic genetic array and HIPHOP chemogenomics. In this retrospective, we briefly describe the yeast deletion project and some of its most noteworthy biological contributions and the impact that these collections have had on the yeast research community and on genomics in general. Copyright © 2014 by the Genetics Society of America.

  14. Biochemical characterization and growth patterns of new yeast isolates.

    Science.gov (United States)

    Djegui, Kadjogbé Y; Gachomo, Emma W; Hounhouigan, Djidjoho J; Kayodé, Adéchola P P; Kotchoni, Simeon O

    2014-08-01

    African sorghum opaque beers play a vital role in the diet of millions of consumers. In the current study we investigated the growth profiles of yeast strains isolated from kpete-kpete, a traditional starter used to produce tchoukoutou, an opaque sorghum beer in Benin. 10 yeast strains were isolated from sorghum beer starters and cultivated under both liquid and solid media for phenotypic growth characterization. All yeast isolates were able to grow both on solid and liquid media. Based on their growth profiles, the isolates were clustered into three groups: (i) the aggressive growth pattern (30%), (ii) the moderate growth pattern (50%), and (iii) the slow growth pattern (20%). Based on gene expression pattern, absorbance (A(600 nm)) and diameter of growth in both liquid and solid media respectively, yeast strains YK34, YK15 and YK48 were clustered in the first group, and referred to as the most aggressive growth strains, followed by group 2 (YK24, YK5, YK12, YK20, YK2) and group 3 (YK37, YK41). This growth pattern was confirmed by Invertase gene expression profiling of the yeasts showing group 1 with high level of Invertase gene expression followed by group 2 and group 3 respectively. Our results suggest that YK34, YK15 and YK48 and YK2 yeast strains constitute the best candidates in fermentation of sorghum beer production based on growth rate and assimilation of carbon and nitrogen sources.

  15. Yeast diversity on grapes in two German wine growing regions.

    Science.gov (United States)

    Brysch-Herzberg, Michael; Seidel, Martin

    2015-12-01

    The yeast diversity on wine grapes in Germany, one of the most northern wine growing regions of the world, was investigated by means of a culture dependent approach. All yeast isolates were identified by sequence analysis of the D1/D2 domain of the 26S rDNA and the ITS region. Besides Hanseniaspora uvarum and Metschnikowia pulcherrima, which are well known to be abundant on grapes, Metschnikowia viticola, Rhodosporidium babjevae, and Curvibasidium pallidicorallinum, as well as two potentially new species related to Sporidiobolus pararoseus and Filobasidium floriforme, turned out to be typical members of the grape yeast community. We found M. viticola in about half of the grape samples in high abundance. Our data strongly suggest that M. viticola is one of the most important fermenting yeast species on grapes in the temperate climate of Germany. The frequent occurrence of Cu. pallidicorallinum and strains related to F. floriforme is a new finding. The current investigation provides information on the distribution of recently described yeast species, some of which are known from a very few strains up to now. Interestingly yeasts known for their role in the wine making process, such as Saccharomyces cerevisiae, Saccharomyces bayanus ssp. uvarum, Torulaspora delbrueckii, and Zygosaccharomyces bailii, were not found in the grape samples.

  16. Association between Grape Yeast Communities and the Vineyard Ecosystems

    Science.gov (United States)

    Drumonde-Neves, João; Lima, Teresa; Schuller, Dorit; Pais, Célia

    2017-01-01

    The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Açores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viticultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions. PMID:28085916

  17. Yeasts and yeast-like fungal contaminants of water used for domestic purposes in Jos, Nigeria

    Directory of Open Access Journals (Sweden)

    Grace Mebi Ayanbimpe

    2013-01-01

    Full Text Available Water used for domestic purposes is ideally required to be free from contaminants. Various contaminants have frequently affected the quality of such water. Water samples were obtained from 150 sources including 72 wells, 60 streams, 17 taps, and one borehole, randomly selected from five residential areas in Jos, Nigeria. Structured questionnaires and one-to- one interview was used to obtain information on features of location and use of facilities in each area. Eighty (53.3% water sources were contaminated, predominantly wells (70.8%. The locations (identified in code with the highest number of contaminated sources were AGO (60.0%, GBU (56.7% and FGD (56.7%. AGD and FGD also had the highest ratio of households to one water source (25:1. Eighty- two fungi were isolated, predominantly Candida tropicalis (23.2%, Candida lipolytica (10.9% and Rhodotorula sp (9.7%. Candida lipolytica was the highest (42.9% contaminant in tap water. Rhodotorula sp was found in all types of water sources sampled. Type of water source had a significant effect (P<0.05 on the presence of some fungi in the water. The residential area (Location had a significant effect on contamination of water sources by some yeasts. Water sources for domestic use in Jos are contaminated by yeasts and yeast-like fungi. Frequency of use, exposure of the facility to dirt, and contaminations of surroundings contribute to the occurrence of fungi in water sources and, by implication, the prevalence of fungal infections.

  18. Comparison of RapID Yeast Plus System with API 20C System for Identification of Common, New, and Emerging Yeast Pathogens

    OpenAIRE

    Espinel-Ingroff, A; Stockman, L.; Roberts, G.; Pincus, D; Pollack, J; Marler, J.

    1998-01-01

    The ability to identify yeast isolates by the new enzymatic RapID Yeast Plus System was compared to the ability to identify yeast isolates by the API 20C system. A total of 447 yeast isolates representing Blastoschizomyces capitatus, 17 Candida spp., 5 Cryptococcus spp., Geotrichum spp., 2 Hanseniaspora spp., Hansenula anomala, Hansenula wingei, 3 Rhodotorula spp., Saccharomyces cerevisiae, Sporobolomyces salmonicolor, Trichosporon beigelii, and 2 Prototheca spp. were evaluated. Also, five qu...

  19. In vitro antifungal activity of fluconazole and voriconazole against non-Candida yeasts and yeast-like fungi clinical isolates.

    Science.gov (United States)

    Mandras, Narcisa; Roana, Janira; Scalas, Daniela; Fucale, Giacomo; Allizond, Valeria; Banche, Giuliana; Barbui, Anna; Li Vigni, Nicolò; Newell, Vance A; Cuffini, Anna Maria; Tullio, Vivian

    2015-10-01

    The risk of opportunistic infections caused by non-Candida yeasts and yeast-like fungi is increasingly common, mainly in immunocompromised patients. Appropriate first-line therapy has not been defined and standardized, mainly due to the low number of cases reported. To improve empirical treatment guidelines, we describe the susceptibility profile to fluconazole and voriconazole of 176 non-Candida yeasts and yeast-like fungi collected from hospitals in Piedmont, North West Italy from January 2009 to December 2013. The results showed that most isolates are susceptible to voriconazole (94%), but less susceptible to fluconazole (78%), suggesting that voriconazole could be used as first-line therapy in infections caused by these fungi.

  20. Yeast Interacting Proteins Database: YLL049W, YMR294W [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available ant shows a reduced affinity for the alcian blue dye suggesting a decreased net negative charge of the cell ...surface Rows with this bait as bait (3) Rows with this bait as prey (1) YMR294W JNM1 Component of the yeast ... null mutant shows a reduced affinity for the alcian blue dye suggesting a decreased net negative charge of ...s with this bait as prey (1) Prey ORF YMR294W Prey gene name JNM1 Prey description Component of the ye

  1. Prevalence of candida and non-candida yeasts isolated from patients with yeast fungal infections in Tehran labs

    Directory of Open Access Journals (Sweden)

    Hashemi SJ

    2011-04-01

    Full Text Available "n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Infections caused by opportunistic yeasts such as Candida species, Trichosporon, Rhodotorula and Saccharomyces have increased in immunocompromis-ed patients and their identification is crucial as intrinsic and acquired resistance of some yeast species to antifungal agents are on the rise. The aim of this study was to identify the organisms to the species level in order to suggest accurate and effective antifungal therapies."n"nMethods: In this study that carried out in Tehran, Iran in 2009, 200 patients with yeast infection were medically examined and clinical specimens were prepared for direct examination and culture on Sabouraud dextrose agar. Subsequently, the isolated yeast colonies were identified using various tests including culture on Corn Meal agar with Tween 80, CHROMagar Candida and casein agar. For the definite identification of organisms some biochemical tests were done based on carbohydrate assimilation by RapID Yeast Plus System kit, and, finally, a molecular method, PCR-RFLP, using Hpa II enzyme, was performed for the remaining unknown yeast species."n"nResults: A total of 211 yeast isolates were identified in 200 patients with yeast infections. The most frequent isolated yeasts were Candida albicans, 124 (58.77%, followed by Candida parapsilosis, 36 (17.06%, Candida tropicalis, 17 (8.06%, Candida glabrata, 13 (6.16%, Candida krusei, 8 (3.79%, Candida guilliermondii, 2 (0.96%, Trichosporon, 3 (1.14%, Rhodotorula, 1 (0.47%, Saccaromyces cerevisiae, 1 (0.47% and other

  2. Electrochemical regulation of budding yeast polarity.

    Directory of Open Access Journals (Sweden)

    Armin Haupt

    2014-12-01

    Full Text Available Cells are naturally surrounded by organized electrical signals in the form of local ion fluxes, membrane potential, and electric fields (EFs at their surface. Although the contribution of electrochemical elements to cell polarity and migration is beginning to be appreciated, underlying mechanisms are not known. Here we show that an exogenous EF can orient cell polarization in budding yeast (Saccharomyces cerevisiae cells, directing the growth of mating projections towards sites of hyperpolarized membrane potential, while directing bud emergence in the opposite direction, towards sites of depolarized potential. Using an optogenetic approach, we demonstrate that a local change in membrane potential triggered by light is sufficient to direct cell polarization. Screens for mutants with altered EF responses identify genes involved in transducing electrochemical signals to the polarity machinery. Membrane potential, which is regulated by the potassium transporter Trk1p, is required for polarity orientation during mating and EF response. Membrane potential may regulate membrane charges through negatively charged phosphatidylserines (PSs, which act to position the Cdc42p-based polarity machinery. These studies thus define an electrochemical pathway that directs the orientation of cell polarization.

  3. Pulsatile dynamics in the yeast proteome.

    Science.gov (United States)

    Dalal, Chiraj K; Cai, Long; Lin, Yihan; Rahbar, Kasra; Elowitz, Michael B

    2014-09-22

    The activation of transcription factors in response to environmental conditions is fundamental to cellular regulation. Recent work has revealed that some transcription factors are activated in stochastic pulses of nuclear localization, rather than at a constant level, even in a constant environment [1-12]. In such cases, signals control the mean activity of the transcription factor by modulating the frequency, duration, or amplitude of these pulses. Although specific pulsatile transcription factors have been identified in diverse cell types, it has remained unclear how prevalent pulsing is within the cell, how variable pulsing behaviors are between genes, and whether pulsing is specific to transcriptional regulators or is employed more broadly. To address these issues, we performed a proteome-wide movie-based screen to systematically identify localization-based pulsing behaviors in Saccharomyces cerevisiae. The screen examined all genes in a previously developed fluorescent protein fusion library of 4,159 strains [13] in multiple media conditions. This approach revealed stochastic pulsing in ten proteins, all transcription factors. In each case, pulse dynamics were heterogeneous and unsynchronized among cells in clonal populations. Pulsing is the only dynamic localization behavior that we observed, and it tends to occur in pairs of paralogous and redundant proteins. Taken together, these results suggest that pulsatile dynamics play a pervasive role in yeast and may be similarly prevalent in other eukaryotic species.

  4. Genetic landscape of open chromatin in yeast.

    Directory of Open Access Journals (Sweden)

    Kibaick Lee

    Full Text Available Chromatin regulation underlies a variety of DNA metabolism processes, including transcription, recombination, repair, and replication. To perform a quantitative genetic analysis of chromatin accessibility, we obtained open chromatin profiles across 96 genetically different yeast strains by FAIRE (formaldehyde-assisted isolation of regulatory elements assay followed by sequencing. While 5∼10% of open chromatin region (OCRs were significantly affected by variations in their underlying DNA sequences, subtelomeric areas as well as gene-rich and gene-poor regions displayed high levels of sequence-independent variation. We performed quantitative trait loci (QTL mapping using the FAIRE signal for each OCR as a quantitative trait. While individual OCRs were associated with a handful of specific genetic markers, gene expression levels were associated with many regulatory loci. We found multi-target trans-loci responsible for a very large number of OCRs, which seemed to reflect the widespread influence of certain chromatin regulators. Such regulatory hotspots were enriched for known regulatory functions, such as recombinational DNA repair, telomere replication, and general transcription control. The OCRs associated with these multi-target trans-loci coincided with recombination hotspots, telomeres, and gene-rich regions according to the function of the associated regulators. Our findings provide a global quantitative picture of the genetic architecture of chromatin regulation.

  5. The Cell Biology of Fission Yeast Septation.

    Science.gov (United States)

    García Cortés, Juan C; Ramos, Mariona; Osumi, Masako; Pérez, Pilar; Ribas, Juan Carlos

    2016-09-01

    In animal cells, cytokinesis requires the formation of a cleavage furrow that divides the cell into two daughter cells. Furrow formation is achieved by constriction of an actomyosin ring that invaginates the plasma membrane. However, fungal cells contain a rigid extracellular cell wall surrounding the plasma membrane; thus, fungal cytokinesis also requires the formation of a special septum wall structure between the dividing cells. The septum biosynthesis must be strictly coordinated with the deposition of new plasma membrane material and actomyosin ring closure and must occur in such a way that no breach in the cell wall occurs at any time. Because of the high turgor pressure in the fungal cell, even a minor local defect might lead to cell lysis and death. Here we review our knowledge of the septum structure in the fission yeast Schizosaccharomyces pombe and of the recent advances in our understanding of the relationship between septum biosynthesis and actomyosin ring constriction and how the two collaborate to build a cross-walled septum able to support the high turgor pressure of the cell. In addition, we discuss the importance of the septum biosynthesis for the steady ingression of the cleavage furrow.

  6. Modular assembly of yeast cytochrome oxidase.

    Science.gov (United States)

    McStay, Gavin P; Su, Chen Hsien; Tzagoloff, Alexander

    2013-02-01

    Previous studies of yeast cytochrome oxidase (COX) biogenesis identified Cox1p, one of the three mitochondrially encoded core subunits, in two high-molecular weight complexes combined with regulatory/assembly factors essential for expression of this subunit. In the present study we use pulse-chase labeling experiments in conjunction with isolated mitochondria to identify new Cox1p intermediates and place them in an ordered pathway. Our results indicate that before its assimilation into COX, Cox1p transitions through five intermediates that are differentiated by their compositions of accessory factors and of two of the eight imported subunits. We propose a model of COX biogenesis in which Cox1p and the two other mitochondrial gene products, Cox2p and Cox3p, constitute independent assembly modules, each with its own complement of subunits. Unlike their bacterial counterparts, which are composed only of the individual core subunits, the final sequence in which the mitochondrial modules associate to form the holoenzyme may have been conserved during evolution.

  7. Computational Modeling of Lipid Metabolism in Yeast

    Directory of Open Access Journals (Sweden)

    Vera Schützhold

    2016-09-01

    Full Text Available Lipid metabolism is essential for all major cell functions and has recently gained increasing attention in research and health studies. However, mathematical modeling by means of classical approaches such as stoichiometric networks and ordinary differential equation systems has not yet provided satisfactory insights, due to the complexity of lipid metabolism characterized by many different species with only slight differences and by promiscuous multifunctional enzymes.Here, we present a object-oriented stochastic model approach as a way to cope with the complex lipid metabolic network. While all lipid species are treated objects in the model, they can be modified by the respective converting reactions based on reaction rules, a hybrid method that integrates benefits of agent-based and classical stochastic simulation. This approach allows to follow the dynamics of all lipid species with different fatty acids, different degrees of saturation and different headgroups over time and to analyze the effect of parameter changes, potential mutations in the catalyzing enzymes or provision of different precursors. Applied to yeast metabolism during one cell cycle period, we could analyze the distribution of all lipids to the various membranes in time-dependent manner.The presented approach allows to efficiently treat the complexity of cellular lipid metabolism and to derive conclusions on the time- and location-dependent distributions of lipid species and their properties such as saturation. It is widely applicable, easily extendable and will provide further insights in healthy and diseased states of cell metabolism.

  8. A unified model for yeast transcript definition.

    Science.gov (United States)

    de Boer, Carl G; van Bakel, Harm; Tsui, Kyle; Li, Joyce; Morris, Quaid D; Nislow, Corey; Greenblatt, Jack F; Hughes, Timothy R

    2014-01-01

    Identifying genes in the genomic context is central to a cell's ability to interpret the genome. Yet, in general, the signals used to define eukaryotic genes are poorly described. Here, we derived simple classifiers that identify where transcription will initiate and terminate using nucleic acid sequence features detectable by the yeast cell, which we integrate into a Unified Model (UM) that models transcription as a whole. The cis-elements that denote where transcription initiates function primarily through nucleosome depletion, and, using a synthetic promoter system, we show that most of these elements are sufficient to initiate transcription in vivo. Hrp1 binding sites are the major characteristic of terminators; these binding sites are often clustered in terminator regions and can terminate transcription bidirectionally. The UM predicts global transcript structure by modeling transcription of the genome using a hidden Markov model whose emissions are the outputs of the initiation and termination classifiers. We validated the novel predictions of the UM with available RNA-seq data and tested it further by directly comparing the transcript structure predicted by the model to the transcription generated by the cell for synthetic DNA segments of random design. We show that the UM identifies transcription start sites more accurately than the initiation classifier alone, indicating that the relative arrangement of promoter and terminator elements influences their function. Our model presents a concrete description of how the cell defines transcript units, explains the existence of nongenic transcripts, and provides insight into genome evolution.

  9. Mechanical feedback stabilizes budding yeast morphogenesis

    Science.gov (United States)

    Banavar, Samhita; Trogdon, Michael; Petzold, Linda; Campas, Otger

    Walled cells have the ability to remodel their shape while sustaining an internal turgor pressure that can reach values up to 10 atmospheres. This requires a tight and simultaneous regulation of cell wall assembly and mechanochemistry, but the underlying mechanisms by which this is achieved remain unclear. Using the growth of mating projections in budding yeast (S. cerevisiae) as a motivating example, we have developed a theoretical description that couples the mechanics of cell wall expansion and assembly via a mechanical feedback. In the absence of a mechanical feedback, cell morphogenesis is inherently unstable. The presence of a mechanical feedback stabilizes changes in cell shape and growth, and provides a mechanism to prevent cell lysis in a wide range of conditions. We solve for the dynamics of the system and obtain the different dynamical regimes. In particular, we show that several parameters affect the stability of growth, including the strength of mechanical feedback in the system. Finally, we compare our results to existing experimental data.

  10. Metals uptake by live yeast and heat-modified yeast residue

    Directory of Open Access Journals (Sweden)

    Geórgia Labuto

    2015-07-01

    Full Text Available This study evaluated the biosorption of Cd2+, Cr3+, Pb2+ and Cu2+ at pHs 3, 4, 5 and 6 for Saccharomyces cerevisiae both alive and biologically inactivated by different heating procedures (oven, autoclave or spray dry technique originated from alcohol industry. The material inactivated by autoclave (IA, at 120°C, 30 min had the best performance for metals uptake: 1.88 ± 0.07 (Cu2+, 2.22 ± 0.02 (Cr3+ and 1.57 ± 0.08 g kg-1 (Pb2+. For Cd2+; while the material inactivated by spray dry (RY presented the higher sorption capacity, 2.30 ± 0.08 g kg-1. The sorption studies showed that the biosorbent materials presented different sorption capacities and an ideal sorption pH. The sorption sites were investigated by potentiometric titration and FT-IR and showed that different heating processes used to inactivate biological samples produce materials with different characteristics and with a diverse sorption capacity due to modification of the available sorption sites. This suggests that inactivation by heating can be an alternative to improve the performance of biosorbents. The main sorption sites for each material were phenolic for live yeast (LY and carboxylic for yeast inactivated by heating in an autoclave (IA.

  11. Mechanisms of uv mutagenesis in yeast and E. coli

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, C.; Christensen, R.; Christensen, J.R.; O' Brien, T.

    1983-01-01

    Experiments investigating ultraviolet light mutagenesis in either bakers' yeast, Saccharomyces cerevisiae, or E. coli have led to the following conclusions. First, cyclobutane pyrimidine dimers cause most mutations in both organisms; pyrimidine adducts, such as PyC, can account at best for only a small proportion. 86 percent of forward mutations induced at the E. coli lacI locus can be abolished by photoreactivation under conditions which do not alter the level of recA induction. About 75 percent of the forward mutations induced at the CAN1 locus of yeast could be removed by photoreactivation, a value that lies within the range observed previously for the reversion of CYC1 alleles (60 percent - 97 percent). Second, about 10 percent of the lacI forward mutations are untargeted, a smaller fraction than found previously for cycl-91 reversion in yeast. It is not yet clear whether the two species are really different in this respect, of whether the cycl-91 reversion site is a typical of the yeast genome at large. Third, analysis of reversion frequencies of 20 mutant alleles suggests that about 10 to 25 percent of all replication errors produced by mutagenic mechanisms in uv-irradiated yeast involve additions or deletions of base-pairs, indicating that error-prone repair does not just produce substitutions. Last, the REV1 locus in yeast is concerned with the induction of frameshift mutations at some, but not all, genetic sites, just as found previously for substitution mutations. The function of the REV3 gene is more widely, though not universally, required while the function of the RAD6 gene, like that of the recA locus in E. coli, appears to be necessary for all kinds of uv mutagenesis. E coli genes comparable to REV1 and REV3 have not yet been described; conversely, there does not yet appear to be a yeast equivalent of umuC.

  12. Genome Diversity and Evolution in the Budding Yeasts (Saccharomycotina).

    Science.gov (United States)

    Dujon, Bernard A; Louis, Edward J

    2017-06-01

    Considerable progress in our understanding of yeast genomes and their evolution has been made over the last decade with the sequencing, analysis, and comparisons of numerous species, strains, or isolates of diverse origins. The role played by yeasts in natural environments as well as in artificial manufactures, combined with the importance of some species as model experimental systems sustained this effort. At the same time, their enormous evolutionary diversity (there are yeast species in every subphylum of Dikarya) sparked curiosity but necessitated further efforts to obtain appropriate reference genomes. Today, yeast genomes have been very informative about basic mechanisms of evolution, speciation, hybridization, domestication, as well as about the molecular machineries underlying them. They are also irreplaceable to investigate in detail the complex relationship between genotypes and phenotypes with both theoretical and practical implications. This review examines these questions at two distinct levels offered by the broad evolutionary range of yeasts: inside the best-studied Saccharomyces species complex, and across the entire and diversified subphylum of Saccharomycotina. While obviously revealing evolutionary histories at different scales, data converge to a remarkably coherent picture in which one can estimate the relative importance of intrinsic genome dynamics, including gene birth and loss, vs. horizontal genetic accidents in the making of populations. The facility with which novel yeast genomes can now be studied, combined with the already numerous available reference genomes, offer privileged perspectives to further examine these fundamental biological questions using yeasts both as eukaryotic models and as fungi of practical importance. Copyright © 2017 by the Genetics Society of America.

  13. Analysis of Arabidopsis glutathione-transferases in yeast.

    Science.gov (United States)

    Krajewski, Matthias P; Kanawati, Basem; Fekete, Agnes; Kowalski, Natalie; Schmitt-Kopplin, Philippe; Grill, Erwin

    2013-07-01

    The genome of Arabidopsis thaliana encodes 54 functional glutathione transferases (GSTs), classified in seven clades. Although plant GSTs have been implicated in the detoxification of xenobiotics, such as herbicides, extensive redundancy within this large gene family impedes a functional analysis in planta. In this study, a GST-deficient yeast strain was established as a system for analyzing plant GSTs that allows screening for GST substrates and identifying substrate preferences within the plant GST family. To this end, five yeast genes encoding GSTs and GST-related proteins were simultaneously disrupted. The resulting yeast quintuple mutant showed a strongly reduced conjugation of the GST substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl). Consistently, the quintuple mutant was hypersensitive to CDNB, and this phenotype was complemented by the inducible expression of Arabidopsis GSTs. The conjugating activity of the plant GSTs was assessed by in vitro enzymatic assays and via analysis of exposed yeast cells. The formation of glutathione adducts with dinitrobenzene was unequivocally verified by stable isotope labeling and subsequent accurate ultrahigh-resolution mass spectrometry (ICR-FTMS). Analysis of Arabidopsis GSTs encompassing six clades and 42 members demonstrated functional expression in yeast by using CDNB and NBD-Cl as model substrates. Subsequently, the established yeast system was explored for its potential to screen the Arabidopsis GST family for conjugation of the fungicide anilazine. Thirty Arabidopsis GSTs were identified that conferred increased levels of glutathionylated anilazine. Efficient anilazine conjugation was observed in the presence of the phi, tau, and theta clade GSTs including AtGSTF2, AtGSTF4, AtGSTF6, AtGSTF8, AtGSTF10, and AtGSTT2, none of which had previously been known to contribute to fungicide detoxification. ICR-FTMS analysis of yeast extracts allowed the simultaneous detection and

  14. Ochratoxin A in brewer's yeast used as food supplement.

    Science.gov (United States)

    Gottschalk, Christoph; Biermaier, Barbara; Gross, Madeleine; Schwaiger, Karin; Gareis, Manfred

    2016-02-01

    Brewer's yeasts are rich in vitamins of the B-group and contain other nutritive factors; therefore, they are recommended as valuable food supplements for people with special dietary requirements like pregnant women, children, and adolescents, or for people with high physical activity. Additionally, certain strains of brewer's yeast are known to be capable of adsorbing xenobiotics such as mycotoxins. Because of that, these yeasts are regarded as having positive effects in food, beverage, and feed technology. Their potential to bind mycotoxins such as ochratoxin A (OTA), however, can subsequently lead to a contamination of such brewer's yeasts used as food supplements. In the present study, we analyzed 46 samples of brewer's yeasts for the occurrence of OTA by HPLC with fluorescence detector (HPLC-FLD) and for confirmatory measurements by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nearly 90% of the samples were contaminated with OTA, the levels ranging from the limit of detection (LOD, 0.01 μg/kg) to 4.2 μg/kg. The mean and median levels of contamination were 0.49 and 0.27 μg/kg, respectively. Based on these results, the additional weekly OTA exposure by regularly consuming such supplements was assessed. Depending on different subpopulations (adults, children) and levels of contamination used for calculation, the additional OTA intake via brewer's yeast products ranged from 9.3% (mean case) to 114% (worst case) of the published mean weekly OTA intake in Germany (adults 279.3 ng, children 195.3 ng). At present, maximum levels for OTA in nutritional supplements like brewer's yeast do not exist. Based on our results, however, it is recommended that producers of these dietary supplements should include mycotoxin analyses in ongoing and future self-monitoring programs and in product quality checks.

  15. Solving ethanol production problems with genetically modified yeast strains

    Directory of Open Access Journals (Sweden)

    A. Abreu-Cavalheiro

    2013-09-01

    Full Text Available The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

  16. Intermembrane space proteome of yeast mitochondria.

    Science.gov (United States)

    Vögtle, F-Nora; Burkhart, Julia M; Rao, Sanjana; Gerbeth, Carolin; Hinrichs, Jens; Martinou, Jean-Claude; Chacinska, Agnieszka; Sickmann, Albert; Zahedi, René P; Meisinger, Chris

    2012-12-01

    The intermembrane space (IMS) represents the smallest subcompartment of mitochondria. Nevertheless, it plays important roles in the transport and modification of proteins, lipids, and metal ions and in the regulation and assembly of the respiratory chain complexes. Moreover, it is involved in many redox processes and coordinates key steps in programmed cell death. A comprehensive profiling of IMS proteins has not been performed so far. We have established a method that uses the proapoptotic protein Bax to release IMS proteins from isolated mitochondria, and we profiled the protein composition of this compartment. Using stable isotope-labeled mitochondria from Saccharomyces cerevisiae, we were able to measure specific Bax-dependent protein release and distinguish between quantitatively released IMS proteins and the background efflux of matrix proteins. From the known 31 soluble IMS proteins, 29 proteins were reproducibly identified, corresponding to a coverage of >90%. In addition, we found 20 novel intermembrane space proteins, out of which 10 had not been localized to mitochondria before. Many of these novel IMS proteins have unknown functions or have been reported to play a role in redox regulation. We confirmed IMS localization for 15 proteins using in organello import, protease accessibility upon osmotic swelling, and Bax-release assays. Moreover, we identified two novel mitochondrial proteins, Ymr244c-a (Coa6) and Ybl107c (Mic23), as substrates of the MIA import pathway that have unusual cysteine motifs and found the protein phosphatase Ptc5 to be a novel substrate of the inner membrane protease (IMP). For Coa6 we discovered a role as a novel assembly factor of the cytochrome c oxidase complex. We present here the first and comprehensive proteome of IMS proteins of yeast mitochondria with 51 proteins in total. The IMS proteome will serve as a valuable source for further studies on the role of the IMS in cell life and death.

  17. Characterizing yeast promoters used in Kluyveromyces marxianus.

    Science.gov (United States)

    Yang, Chun; Hu, Shenglin; Zhu, Songli; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

    2015-10-01

    Fermentation at higher temperatures can potentially reduce the cooling cost in large-scale fermentation and reduce the contamination risk. Thus, the thermotolerant yeast, Kluyveromyces marxianus, which can grow and ferment at elevated temperatures, is a promising biotechnological tool for future applications. However, the promoters used in K. marxianus are not well characterized, especially at elevated temperatures, which is important in efficient metabolic pathway construction. In this study, six constitutive promoters (P(TDH3), P(PGK), and P(ADH1) from both Saccharomyces cerevisiae and K. marxianus) were evaluated in K. marxianus through the heterologous expression of the KlLAC4, GUSA, and SH BLE genes at various temperatures, with various carbon sources and oxygen conditions. The expression was evaluated at the transcription and protein level using real-time PCR and protein activity determination to eliminate the effect of heterologous protein stability. While the transcription of all the promoters decreased at higher temperatures, the order of their promoting strength at various temperatures with glucose as the carbon source was P(KmPGK) > P(KmTDH3) > P(ScPGK) > P(ScTDH3) > P(KmADH1) > P(ScADH1). When glycerol or xylose was supplied as the carbon source at 42 °C, the order of promoter strength was P(KmPGK) > P(ScPGK) > P(KmADH1) > P(ScADH1) > P(ScTDH3) > P(KmTDH3). The promoter activity of P TDH3 decreased significantly, while the promoter activity of both of the P(ADH1) promoters increased. Oxygen conditions had non-significant effect. The results of this study provide important information for fine-tuned pathway construction for the metabolic engineering of K. marxianus.

  18. Ethanol production using nuclear petite yeast mutants

    Energy Technology Data Exchange (ETDEWEB)

    Hutter, A.; Oliver, S.G. [Department of Biomolecular Sciences, UMIST, Manchester (United Kingdom)

    1998-12-31

    Two respiratory-deficient nuclear petites, FY23{Delta}pet191 and FY23{Delta}cox5a, of the yeast Saccharomyces cerevisiae were generated using polymerase-chain-reaction-mediated gene disruption, and their respective ethanol tolerance and productivity assessed and compared to those of the parental grande, FY23WT, and a mitochondrial petite, FY23{rho}{sup 0}. Batch culture studies demonstrated that the parental strain was the most tolerant to exogenously added ethanol with an inhibition constant. K{sub i}, of 2.3% (w/v) and a specific rate of ethanol production, q{sub p}, of 0.90 g ethanol g dry cells{sup -1} h{sup -1}. FY23{rho}{sup 0} was the most sensitive to ethanol, exhibiting a K{sub i} of 1.71% (w/v) and q{sub p} of 0.87 g ethanol g dry cells{sup -1} h{sup -1}. Analyses of the ethanol tolerance of the nuclear petites demonstrate that functional mitochondria are essential for maintaining tolerance to the toxin with the 100% respiratory-deficient nuclear petite, FY23{Delta}pet191, having a K{sub i} of 2.14% (w/v) and the 85% respiratory-deficient FY23{Delta}cox5a, having a K{sub i} of 1.94% (w/v). The retention of ethanol tolerance in the nuclear petites as compared to that of FY23{rho}{sup 0} is mirrored by the ethanol productivities of these nuclear mutants, being respectively 43% and 30% higher than that of the respiratory-sufficient parent strain. This demonstrates that, because of their respiratory deficiency, the nuclear petites are not subject of the Pasteur effect and so exhibit higher rates of fermentation. (orig.)

  19. A Comparison of the Beneficial Effects of Live and Heat-Inactivated Baker's Yeast on Nile Tilapia: Suggestions on the Role and Function of the Secretory Metabolites Released from the Yeast

    National Research Council Canada - National Science Library

    Ran, Chao; Huang, Lu; Liu, Zhi; Xu, Li; Yang, Yalin; Tacon, Philippe; Auclair, Eric; Zhou, Zhigang

    2015-01-01

    .... In this study, the involvement and extent to which the viability of yeast cells and thus the secretory metabolites released from the yeast contribute to effects of baker's yeast was investigated in Nile tilapia...

  20. A Comparison of the Beneficial Effects of Live and Heat-Inactivated Baker's Yeast on Nile Tilapia: Suggestions on the Role and Function of the Secretory Metabolites Released from the Yeast: e0145448

    National Research Council Canada - National Science Library

    Chao Ran; Lu Huang; Zhi Liu; Li Xu; Yalin Yang; Philippe Tacon; Eric Auclair; Zhigang Zhou

    2015-01-01

    .... In this study, the involvement and extent to which the viability of yeast cells and thus the secretory metabolites released from the yeast contribute to effects of baker's yeast was investigated in Nile tilapia...

  1. Lipase production by yeasts from extra virgin olive oil.

    Science.gov (United States)

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

    2006-02-01

    Newly produced olive oil has an opalescent appearance due to the presence of solid particles and micro-drops of vegetation water from the fruits. Some of our recent microbiological research has shown that a rich micro-flora is present in the suspended fraction of the freshly produced olive oil capable of improving the quality of the oil through the hydrolysis of the oleuropein. Present research however has, for the first time, demonstrated the presence of lipase-positive yeasts in some samples of extra virgin olive oil which can lower the quality of the oil through the hydrolysis of the triglycerides. The tests performed with yeasts of our collection, previously isolated from olive oil, demonstrated that two lipase-producing yeast strains named Saccharomyces cerevisiae 1525 and Williopsis californica 1639 were able to hydrolyse different specific synthetic substrates represented by p-nitrophenyl stearate, 4-nitrophenyl palmitate, tripalmitin and triolein as well as olive oil triglycerides. The lipase activity in S. cerevisiae 1525 was confined to the whole cells, whereas in W. californica 1639 it was also detected in the extracellular fraction. The enzyme activity in both yeasts was influenced by the ratio of the aqueous to the organic phase reaching its maximum value in S. cerevisiae 1525 when the water added to the olive oil was present in a ratio of 0.25% (v/v), whereas in W. californica 1639 the optimal ratio was 1% (v/v). Furthermore, the free fatty acids of olive oil proved to be good inducers of lipase activity in both yeasts. The microbiological analysis carried out on commercial extra virgin olive oil, produced in four different geographic areas, demonstrated that the presence of lipase-producing yeast varied from zero to 56% of the total yeasts detected, according to the source of oil samples. The discovery of lipase-positive yeasts in some extra virgin olive oils leads us to believe that yeasts are able to contribute in a positive or negative way towards

  2. Ability of RapID Yeast Plus System to identify 304 clinically significant yeasts within 5 hours.

    Science.gov (United States)

    Kitch, T T; Jacobs, M R; McGinnis, M R; Appelbaum, P C

    1996-05-01

    The RapID Yeast Plus System (Innovative Diagnostic Systems, Norcross, Ga.) is a qualitative micromethod that uses conventional and chromogenic substrates for the identification of medically important yeasts. The ability of the RapID Yeast Plus system to accurately identify 304 clinical yeast isolates within 5 h was evaluated. The RapID Yeast Plus method correctly identified 286 (94.1%) of strains to the species level without the need for additional tests. A further 12 strains (3.9%) were classified as correct to the genus level or to a low-probability identification with two or more possibilities. In these latter cases, additional tests were required to delineate the correct identification. Organisms in the latter group comprised Candida parapsilosis (n = 1), Candida tropicalis (n = 1), Candida ciferrii (n = 1), Candida guilliermondii (n = 2), Candida humicola (n = 1), Candida kefyr (n = 1), Cryptococcus neoformans (n = 1), and Rhodotorula rubra (n = 4). Six strains (2.0%) were misidentified or did not yield codes in the manufacturer's database. These included one Candida utilis (identified as Candida famata/Candida guilliermondii), one Trichosporon beigelii (identified as Cryptococcus neoformans), one Candida diddensiae (identified as Candida albicans), one Candida membranaefaciens (identified as Candida parapsilosis), one Candida norvegensis (identified as Candida zeylanoides), and one Candida catenulata (no code) isolate; the last four strains are not included in the firm's current database. The RapID Yeast Plus system yielded excellent results and may be recommended for use in the routine laboratory for accurate same-day identification of clinically significant yeasts.

  3. Yeast selection for fuel ethanol production in Brazil.

    Science.gov (United States)

    Basso, Luiz C; de Amorim, Henrique V; de Oliveira, Antonio J; Lopes, Mario L

    2008-11-01

    Brazil is one of the largest ethanol biofuel producers and exporters in the world and its production has increased steadily during the last three decades. The increasing efficiency of Brazilian ethanol plants has been evident due to the many technological contributions. As far as yeast is concerned, few publications are available regarding the industrial fermentation processes in Brazil. The present paper reports on a yeast selection program performed during the last 12 years aimed at selecting Saccharomyces cerevisiae strains suitable for fermentation of sugar cane substrates (cane juice and molasses) with cell recycle, as it is conducted in Brazilian bioethanol plants. As a result, some evidence is presented showing the positive impact of selected yeast strains in increasing ethanol yield and reducing production costs, due to their higher fermentation performance (high ethanol yield, reduced glycerol and foam formation, maintenance of high viability during recycling and very high implantation capability into industrial fermenters). Results also suggest that the great yeast biodiversity found in distillery environments could be an important source of strains. This is because during yeast cell recycling, selective pressure (an adaptive evolution) is imposed on cells, leading to strains with higher tolerance to the stressful conditions of the industrial fermentation.

  4. Oxygen requirements of yeasts. [Saccharomyces cerevisiae; Candida tropicalis

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-01

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

  5. Cellular and molecular effects of yeast probiotics on cancer.

    Science.gov (United States)

    Saber, Amir; Alipour, Beitollah; Faghfoori, Zeinab; Yari Khosroushahi, Ahmad

    2017-02-01

    The cancer is one of the main causes of human deaths worldwide. The exact mechanisms of initiation and progression of malignancies are not clear yet, but there is a common agreement about the role of colonic microbiota in the etiology of different cancers. Probiotics have been examined for their anti-cancer effects, and different mechanisms have been suggested about their antitumor functions. Nonpathogenic yeasts, as members of probiotics family, can be effective on gut microbiota dysbiosis. Generally safe yeasts have shown so many beneficial effects on human health. Probiotic yeasts influence physiology, metabolism, and immune homeostasis in the colon and contribute to cancer treatment due to possessing anti-inflammatory, anti-proliferative and anti-cancer properties. This study reviews some of the health-beneficial effects of probiotic yeasts and their biological substances like folic acid and β-glucan on cancer and focuses on the possible cellular and molecular mechanisms of probiotic yeasts such as influencing pathogenic bacteria, inactivation of carcinogenic compounds, especially those derived from food, improvement of intestinal barrier function, modulation of immune responses, antitoxic function, apoptosis, and anti-proliferative effects.

  6. Isolation and identification of a riboflavin producer yeast from Nectarine

    Directory of Open Access Journals (Sweden)

    Roya Daneshazari

    2014-07-01

    Full Text Available   Introduction : Many microorganisms like fungi , bacteria and yeasts, have a natural ability to produce vitamins included vitamin B2 or riboflavin. In this regard, the present study was performed to isolation and screening for riboflavin producing yeasts from various sources of soil, leaf and fruit s.   Materials and method s: samples of leaf , soil and fruits were prepared for the presence of yeasts and by its ability to produce riboflavin . After purification and enrichment of samples , in order to assay riboflavin production, spectrometry , thin layer chromatography and high performance liquid chromatography were used . Finally, the best selected isolate was identified using conventional morphological , biochemical and molecular techniques .   Results : In this study , 26 yeast strains were isolated from environmental samples, that 6 isolates showed the ability to produce riboflavin . Identification results of the best selected isolate by biochemical and phenotypic characteristics revealed that this isolate is related to Clavispora lusitaniae and considering isolation of it from nectarine, has named it Clavispora lusitaniae strain N3 (Gene accession no: JQ586258 .   Discussion and conclusion : Although only one of the six producing strains was studied and identified , observation of ability to produce among 23% of strains showed necessity for further investigation. And according to the result of absence of viewing report about production by investigated strain, it can be said that Iran has potentiality for isolation of yeasts and is capable of producing riboflavin.

  7. The yeast Saccharomyces cerevisiae- the main character in beer brewing.

    Science.gov (United States)

    Lodolo, Elizabeth J; Kock, Johan L F; Axcell, Barry C; Brooks, Martin

    2008-11-01

    Historically, mankind and yeast developed a relationship that led to the discovery of fermented beverages. Numerous inventions have led to improved technologies and capabilities to optimize fermentation technology on an industrial scale. The role of brewing yeast in the beer-making process is reviewed and its importance as the main character is highlighted. On considering the various outcomes of functions in a brewery, it has been found that these functions are focused on supporting the supply of yeast requirements for fermentation and ultimately to maintain the integrity of the product. The functions/processes include: nutrient supply to the yeast (raw material supply for brewhouse wort production); utilities (supply of water, heat and cooling); quality assurance practices (hygiene practices, microbiological integrity measures and other specifications); plant automation (vessels, pipes, pumps, valves, sensors, stirrers and centrifuges); filtration and packaging (product preservation until consumption); distribution (consumer supply); and marketing (consumer awareness). Considering this value chain of beer production and the 'bottle neck' during production, the spotlight falls on fermentation, the age-old process where yeast transforms wort into beer.

  8. Yeast vitality during cider fermentation: assessment by energy metabolism.

    Science.gov (United States)

    Dinsdale, M G; Lloyd, D; McIntyre, P; Jarvis, B

    1999-03-15

    In an apple juice-based medium, an ethanol-tolerant Australian wine-yeast used for cider manufacture produced more than 10% ethanol over a 5 week period. Growth of the inoculum (10(6) organisms ml(-1)) occurred to a population of 3.1 x 10(7) ml(-1) during the first few days; at the end of the fermentation only 5 x 10(5) yeasts ml(-1) could be recovered as colony-forming units on plates. Respiratory and fermentative activities were measured by mass spectrometric measurements (O2 consumption and CO2 and ethanol production) of washed yeast suspensions taken from the cider fermentation at intervals. Both endogenous and glucose-supported energy-yielding metabolism declined, especially during the first 20 days. Levels of adenine nucleotides also showed decreases after day 1, as did adenylate energy charge, although in a prolonged (16.5 week) fermentation the lowest value calculated was 0.55. AMP was released into the medium. 31P-NMR spectra showed that by comparison with aerobically grown yeast, that from the later stages of the cider fermentation showed little polyphosphate. However, as previously concluded from studies of 'acidification power' and fluorescent oxonol dye exclusion (Dinsdale et al., 1995), repitching of yeast indicated little loss of viability despite considerable loss of vitality.

  9. Influence of sodium chloride on wine yeast fermentation performance

    Directory of Open Access Journals (Sweden)

    Stilianos Logothetis

    2010-06-01

    Full Text Available Stilianos Logothetis1, Elias T Nerantzis2, Anna Gioulioti3, Tasos Kanelis2, Tataridis Panagiotis2, Graeme Walker11University of Abertay Dundee, School of Contemporary Sciences, Dundee, Scotland; 2TEI of Athens Department of Oenology and Spirit Technology, Biotechnology and Industrial Fermentations Lab Agiou Spiridonos, Athens, Greece; 3Ampeloiniki SA Industrial Park Thermi, Thessaloniki, GreeceAbstract: This paper concerns research into the influence of salt (sodium chloride on growth, viability and fermentation performance in a winemaking strain of the yeast, Saccharomyces cerevisiae. Experimental fermentations were conducted in both laboratory-scale and industrial-scale experiments. Preculturing yeasts in elevated levels of sodium chloride, or salt “preconditioning” led to improved fermentation performance. This was manifest by preconditioned yeasts having an improved capability to ferment high-sugar containing media with increased cell viability and with elevated levels of produced ethanol. Salt-preconditioning most likely influenced the stress-tolerance of yeasts by inducing the synthesis of key metabolites such as trehalose and glycerol. These compounds may act to improve cells’ ability to withstand osmostress and ethanol toxicity during fermentations of grape must. Industrial-scale trials using salt-preconditioned yeasts verified the benefit of this novel physiological cell engineering approach to practical winemaking fermentations.Keywords: salt, preconditioning, fermentation performance, Saccharomyces cerevisiae, wine

  10. Yeast prions: structure, biology, and prion-handling systems.

    Science.gov (United States)

    Wickner, Reed B; Shewmaker, Frank P; Bateman, David A; Edskes, Herman K; Gorkovskiy, Anton; Dayani, Yaron; Bezsonov, Evgeny E

    2015-03-01

    A prion is an infectious protein horizontally transmitting a disease or trait without a required nucleic acid. Yeast and fungal prions are nonchromosomal genes composed of protein, generally an altered form of a protein that catalyzes the same alteration of the protein. Yeast prions are thus transmitted both vertically (as genes composed of protein) and horizontally (as infectious proteins, or prions). Formation of amyloids (linear ordered β-sheet-rich protein aggregates with β-strands perpendicular to the long axis of the filament) underlies most yeast and fungal prions, and a single prion protein can have any of several distinct self-propagating amyloid forms with different biological properties (prion variants). Here we review the mechanism of faithful templating of protein conformation, the biological roles of these prions, and their interactions with cellular chaperones, the Btn2 and Cur1 aggregate-handling systems, and other cellular factors governing prion generation and propagation. Human amyloidoses include the PrP-based prion conditions and many other, more common amyloid-based diseases, several of which show prion-like features. Yeast prions increasingly are serving as models for the understanding and treatment of many mammalian amyloidoses. Patients with different clinical pictures of the same amyloidosis may be the equivalent of yeasts with different prion variants.

  11. Systems Biology for Mapping Genotype-Phenotype Relations in Yeast

    KAUST Repository

    Nielsen, Jens

    2016-01-25

    The yeast Saccharomyces cerevisiae is widely used for production of fuels, chemicals, pharmaceuticals and materials. Through metabolic engineering of this yeast a number of novel new industrial processes have been developed over the last 10 years. Besides its wide industrial use, S. cerevisiae serves as an eukaryal model organism, and many systems biology tools have therefore been developed for this organism. Among these genome-scale metabolic models have shown to be most successful as they easy integrate with omics data and at the same time have been shown to have excellent predictive power. Despite our extensive knowledge of yeast metabolism and its regulation we are still facing challenges when we want to engineer complex traits, such as improved tolerance to toxic metabolites like butanol and elevated temperatures or when we want to engineer the highly complex protein secretory pathway. In this presentation it will be demonstrated how we can combine directed evolution with systems biology analysis to identify novel targets for rational design-build-test of yeast strains that have improved phenotypic properties. In this lecture an overview of systems biology of yeast will be presented together with examples of how genome-scale metabolic modeling can be used for prediction of cellular growth at different conditions. Examples will also be given on how adaptive laboratory evolution can be used for identifying targets for improving tolerance towards butanol, increased temperature and low pH and for improving secretion of heterologous proteins.

  12. Carbonation acceleration of calcium hydroxide nanoparticles: induced by yeast fermentation

    Science.gov (United States)

    Lopez-Arce, Paula; Zornoza-Indart, Ainara

    2015-09-01

    Carbonation of Ca(OH)2 nanoparticles and consolidation of limestone are accelerated by high humidity and a yeast fermentation system that supplies a saturated atmosphere on CO2, H2O vapor and ethanol during 28 days. Nanoparticles were analyzed by X-ray diffraction and differential thermal analyses with thermogravimetry. Spectrophotometry, scanning electron microscopy analyses, and hydric and mechanical tests were also performed in stones specimens. Samples exposed to the yeast environment achieve 100 % relative CaCO3 yield, whereas at high humidity but without the yeast and under laboratory environment, relative yields of 95 % CaCO3 and 15 % CaCO3 are, respectively, reached, with white crusts and glazing left on the stone surfaces when the nanoparticles are applied at a concentration of 25 g/l. The largest increase in the drilling resistance and surface hardness values with slight increase in the capillarity absorption and desorption coefficients and with lesser stone color changes are produced at a concentration of 5 g/l, in the yeast system environment. This especially happens in stone specimens initially with bimodal pore size distributions, more amounts of pores with diameters between 0.1 and 1 µm, higher open porosity values and faster capillary coefficients. An inexpensive and reliable method based on water and yeast-sugar solution is presented to speed up carbonation of Ca(OH)2 nanoparticles used as a consolidating product to improve the mechanical properties of decayed limestone from archaeological and architectural heritage.

  13. Yeasts in table olive processing: desirable or spoilage microorganisms?

    Science.gov (United States)

    Arroyo-López, F N; Romero-Gil, V; Bautista-Gallego, J; Rodríguez-Gómez, F; Jiménez-Díaz, R; García-García, P; Querol, A; Garrido-Fernández, A

    2012-11-01

    Yeasts are unicellular eukaryotic microorganisms isolated from many foods, and are commonly found in table olive processing where they can play a double role. On one hand, these microorganisms can produce spoilage of fruits due to the production of bad odours and flavours, the accumulation of CO(2) leading to swollen containers, the clouding of brines, the softening of fruits and the degradation of lactic acid, which is especially harmful during table olive storage and packaging. But on the other hand, fortunately, yeasts also possess desirable biochemical activities (lipase, esterase, β-glucosidase, catalase, production of killer factors, etc.) with important technological applications in this fermented vegetable. Recently, the probiotic potential of olive yeasts has begun to be evaluated because many species are able to resist the passage through the gastrointestinal tract and show beneficial effects on the host. In this way, yeasts may improve consumers' health by decreasing cholesterol levels, inhibiting pathogens, degrading non assimilated compounds, producing antioxidants and vitamins, adhering to intestinal cells or by maintaining epithelial barrier integrity. Many yeast species, usually also found in table olive processing, such as Wicherhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens and Kluyveromyces lactis, have been reported to exhibit some of these properties. Thus, the selection of the most appropriate strains to be used as starters, alone or in combination with lactic acid bacteria, is a promising research line to develop in a near future which might improve the added value of the commercialized product.

  14. Recent advances in yeast organelle and membrane proteomics.

    Science.gov (United States)

    Premsler, Thomas; Zahedi, René Peiman; Lewandrowski, Urs; Sickmann, Albert

    2009-10-01

    Yeast proteome research comprises two different aspects: with respect to systemic fungal infections (fungemias), invasive candidiasis, for instance by Candida albicans, is among the most common causes of morbidity and mortality particularly in the expanding population of immunocompromised patients, which rises a high medical and pharmaceutical interest in this facultative pathogenic organism. Apart from its clinical relevance, yeast research moreover provides an indispensable source of knowledge regarding fundamental biochemical processes of eukaryotic cells. In this context, the budding yeast Saccharomyces cerevisiae is, in addition to its multiple industrial applications, one of the most extensively used microorganisms and serves as the best understood eukaryotic model system so far. Consequently, numerous studies have focused on gaining insight into the yeast proteome, with protein MS providing a very efficient technology to cope with this task since it enables both protein identification and differential quantification of cellular material. In this review we present an overview of recent advances in yeast organelle and membrane proteomics focusing on the cell wall, plasma membrane, mitochondria and vacuole.

  15. Technological properties of bakers' yeasts in durum wheat semolina dough.

    Science.gov (United States)

    Giannone, Virgilio; Longo, Chiara; Damigella, Arcangelo; Raspagliesi, Domenico; Spina, Alfio; Palumbo, Massimo

    2010-04-01

    Properties of 13 Saccharomyces cerevisiae strains isolated from different sources (traditional sourdoughs, industrial baking yeasts etc.) were studied in dough produced with durum wheat (Sicilian semolina, variety Mongibello). Durum wheat semolina and durum wheat flour are products prepared from grain of durum wheat (Triticum durum Desf.) by grinding or milling processes in which the bran and germ are essentially removed and the remainder is comminuted to a suitable degree of fineness. Acidification and leavening properties of the dough were evaluated. Strains isolated from traditional sourdoughs (DSM PST18864, DSM PST18865 and DSM PST18866) showed higher leavening power, valuable after the first and second hours of fermentation, than commercial baking yeasts. In particular the strain DSM PST 18865 has also been successfully tested in bakery companies for the improvement of production processes. Baking and staling tests were carried out on five yeast strains to evaluate their fermentation ability directly and their resistance to the staling process. Amplified fragment length polymorphism (fAFLP) was used to investigate genetic variations in the yeast strains. This study showed an appreciable biodiversity in the microbial populations of both wild and commercial yeast strains.

  16. Phenol degradation and heavy metal tolerance of Antarctic yeasts.

    Science.gov (United States)

    Fernández, Pablo Marcelo; Martorell, María Martha; Blaser, Mariana G; Ruberto, Lucas Adolfo Mauro; de Figueroa, Lucía Inés Castellanos; Mac Cormack, Walter Patricio

    2017-03-07

    In cold environments, biodegradation of organic pollutants and heavy metal bio-conversion requires the activity of cold-adapted or cold-tolerant microorganisms. In this work, the ability to utilize phenol, methanol and n-hexadecane as C source, the tolerance to different heavy metals and growth from 5 to 30 °C were evaluated in cold-adapted yeasts isolated from Antarctica. Fifty-nine percent of the yeasts were classified as psychrotolerant as they could grow in all the range of temperature tested, while the other 41% were classified as psychrophilic as they only grew below 25 °C. In the assimilation tests, 32, 78, and 13% of the yeasts could utilize phenol, n-hexadecane, and methanol as C source, respectively, but only 6% could assimilate the three C sources evaluated. In relation to heavy metals ions, 55, 68, and 80% were tolerant to 1 mM of Cr(VI), Cd(II), and Cu(II), respectively. Approximately a half of the isolates tolerated all of them. Most of the selected yeasts belong to genera previously reported as common for Antarctic soils, but several other genera were also isolated, which contribute to the knowledge of this cold environment mycodiversity. The tolerance to heavy metals of the phenol-degrading cold-adapted yeasts illustrated that the strains could be valuable as inoculant for cold wastewater treatment in extremely cold environments.

  17. Immobilized yeast bioreactor systems for continuous beer fermentation

    Science.gov (United States)

    Tata; Bower; Bromberg; Duncombe; Fehring; Lau; Ryder; Stassi

    1999-01-01

    Two different types of immobilized yeast bioreactors were examined for continuous fermentation of high-gravity worts. One of these is a fluidized bed reactor (FBR) that employs porous glass beads for yeast immobilization. The second system is a loop reactor containing a porous silicon carbide cartridge (SCCR) for immobilizing the yeast cells. Although there was some residual fermentable sugar in the SCCR system product, nearly complete attenuation of the wort sugars was achieved in either of the systems when operated as a two-stage process. Fermentation could be completed in these systems in only half the time required for a conventional batch process. Both the systems showed similar kinetics of extract consumption, and therefore similar volumetric productivity. As compared to the batch fermentation, total fusel alcohols were lower; total esters, while variable, were generally higher. The yeast biomass production was similar to that in a conventional fermentation process. As would be expected in an accelerated fermentation system, the levels of vicinal diketones (VDKs) were higher. To remove the VDKs, the young beer was heat-treated to convert the VDK precursors and processed through a packed bed immobilized yeast bioreactor for VDK assimilation. The finished product from the FBR system was found to be quite acceptable from a flavor perspective, albeit different from the product from a conventional batch process. Significantly shortened fermentation times demonstrate the feasibility of this technology for beer production.

  18. Dietary glucose regulates yeast consumption in adult Drosophila males

    Directory of Open Access Journals (Sweden)

    Sebastien eLebreton

    2014-12-01

    Full Text Available The adjustment of feeding behavior in response to hunger and satiety contributes to homeostatic regulation in animals. The fruit fly Drosophila melanogaster feeds on yeasts growing on overripe fruit, providing nutrients required for adult survival, reproduction and larval growth. Here, we present data on how the nutritional value of food affects subsequent yeast consumption in Drosophila adult males. After a period of starvation, flies showed intensive yeast consumption. In comparison, flies stopped feeding after having access to a nutritive cornmeal diet. Interestingly, dietary glucose was equally efficient as the complex cornmeal diet. In contrast, flies fed with sucralose, a non-metabolizable sweetener, behaved as if they were starved. The adipokinetic hormone and insulin-like peptides regulate metabolic processes in insects. We did not find any effect of the adipokinetic hormone pathway on this modulation. Instead, the insulin pathway was involved in these changes. Flies lacking the insulin receptor did not respond to nutrient deprivation by increasing yeast consumption. Together these results show the importance of insulin in the regulation of yeast consumption in response to starvation in adult D. melanogaster males.

  19. Responses of Yeast Biocontrol Agents to Environmental Stress

    Science.gov (United States)

    Sui, Yuan; Wisniewski, Michael; Droby, Samir

    2015-01-01

    Biological control of postharvest diseases, utilizing wild species and strains of antagonistic yeast species, is a research topic that has received considerable attention in the literature over the past 30 years. In principle, it represents a promising alternative to chemical fungicides for the management of postharvest decay of fruits, vegetables, and grains. A yeast-based biocontrol system is composed of a tritrophic interaction between a host (commodity), a pathogen, and a yeast species, all of which are affected by environmental factors such as temperature, pH, and UV light as well as osmotic and oxidative stresses. Additionally, during the production process, biocontrol agents encounter various severe abiotic stresses that also impact their viability. Therefore, understanding the ecological fitness of the potential yeast biocontrol agents and developing strategies to enhance their stress tolerance are essential to their efficacy and commercial application. The current review provides an overview of the responses of antagonistic yeast species to various environmental stresses, the methods that can be used to improve stress tolerance and efficacy, and the related mechanisms associated with improved stress tolerance. PMID:25710368

  20. Genetic improvement of brewer's yeast: current state, perspectives and limits.

    Science.gov (United States)

    Saerens, Sofie M G; Duong, C Thuy; Nevoigt, Elke

    2010-05-01

    Brewer's yeast strain optimisation may lead to a more efficient beer production process, better final quality or healthier beer. However, brewer's yeast genetic improvement is very challenging, especially true when it comes to lager brewer's yeast (Saccharomyces pastorianus) which contributes to 90% of the total beer market. This yeast is a genetic hybrid and allopolyploid. While early studies applying traditional genetic approaches encountered many problems, the development of rational metabolic engineering strategies successfully introduced many desired properties into brewer's yeast. Recently, the first genome sequence of a lager brewer's strain became available. This has opened the door for applying advanced omics technologies and facilitating inverse metabolic engineering strategies. The latter approach takes advantage of natural diversity and aims at identifying and transferring the crucial genetic information for an interesting phenotype. In this way, strains can be optimised by introducing "natural" mutations. However, even when it comes to self-cloned strains, severe concerns about genetically modified organisms used in the food and beverage industry are still a major hurdle for any commercialisation. Therefore, research efforts will aim at developing new sophisticated screening methods for the isolation of natural mutants with the desired properties which are based on the knowledge of genotype-phenotype linkage.

  1. Performance of dairy females fed dried yeast from sugar cane

    Directory of Open Access Journals (Sweden)

    Marcia de Oliveira Franco

    2016-05-01

    Full Text Available This study was performed in order to evaluate the effect of dried yeast from sugar cane when replacing soybean meal in dairy heifers’ diets. Twenty-four heifers, with an initial body weight (BW of 178 kg, were distributed in a completely randomized design. The treatments were four levels of inclusion of dried yeast from sugar cane replacing to soybean meal (0, 33, 67 and 100% on a dry matter (DM basis. While there was no difference in DM, neutral detergent fiber (NDF, metabolizable energy or roughage intakes, the intakes of non-fiber carbohydrates and concentrate were increased. The crude protein intake decreased according to the dried yeast from sugar cane when replacing soybean meal. The digestibility coefficients of DM and NDF showed no difference. Replacement of soybean meal with dried yeast from sugar cane had no effect on performance, because average daily gain and body measurements studied were similar for all animals and inclusion levels. Soybean meal can be completely replaced with dried yeast from sugar cane in diets for growing dairy heifers without restrictions; this will not affect the intake, digestibility, physical development of animals or metabolization of protein compounds.

  2. Diversity of soil yeasts isolated from South Victoria Land, Antarctica

    Science.gov (United States)

    Connell, L.; Redman, R.; Craig, S.; Scorzetti, G.; Iszard, M.; Rodriguez, R.

    2008-01-01

    Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken from sites spanning a diversity of soil habitats that were not directly associated with vertebrate activity. A large proportion of yeasts isolated in this study were basidiomycetous species (89%), of which 43% may represent undescribed species, demonstrating that culturable yeasts remain incompletely described in these polar desert soils. Cryptococcus species represented the most often isolated genus (33%) followed by Leucosporidium (22%). Principle component analysis and multiple linear regression using stepwise selection was used to model the relation between abiotic variables (principle component 1 and principle component 2 scores) and yeast biodiversity (the number of species present at a given site). These analyses identified soil pH and electrical conductivity as significant predictors of yeast biodiversity. Species-specific PCR primers were designed to rapidly discriminate among the Dioszegia and Leucosporidium species collected in this study. ?? 2008 Springer Science+Business Media, LLC.

  3. Genome sequence of the lager brewing yeast, an interspecies hybrid.

    Science.gov (United States)

    Nakao, Yoshihiro; Kanamori, Takeshi; Itoh, Takehiko; Kodama, Yukiko; Rainieri, Sandra; Nakamura, Norihisa; Shimonaga, Tomoko; Hattori, Masahira; Ashikari, Toshihiko

    2009-04-01

    This work presents the genome sequencing of the lager brewing yeast (Saccharomyces pastorianus) Weihenstephan 34/70, a strain widely used in lager beer brewing. The 25 Mb genome comprises two nuclear sub-genomes originating from Saccharomyces cerevisiae and Saccharomyces bayanus and one circular mitochondrial genome originating from S. bayanus. Thirty-six different types of chromosomes were found including eight chromosomes with translocations between the two sub-genomes, whose breakpoints are within the orthologous open reading frames. Several gene loci responsible for typical lager brewing yeast characteristics such as maltotriose uptake and sulfite production have been increased in number by chromosomal rearrangements. Despite an overall high degree of conservation of the synteny with S. cerevisiae and S. bayanus, the syntenies were not well conserved in the sub-telomeric regions that contain lager brewing yeast characteristic and specific genes. Deletion of larger chromosomal regions, a massive unilateral decrease of the ribosomal DNA cluster and bilateral truncations of over 60 genes reflect a post-hybridization evolution process. Truncations and deletions of less efficient maltose and maltotriose uptake genes may indicate the result of adaptation to brewing. The genome sequence of this interspecies hybrid yeast provides a new tool for better understanding of lager brewing yeast behavior in industrial beer production.

  4. Table wine from tropical fruits utilizing natural yeast isolates.

    Science.gov (United States)

    Baidya, Dipak; Chakraborty, Ivi; Saha, Jayanta

    2016-03-01

    An attempt was made to utilize few widely available tropical fruits to develop wine with the objective of comparing the fermentation efficiency (along with progress in fermentation) of two efficient yeast isolates with commercially available strain. Fruit wine from juices of fully ripe mango, jackfruit and pineapple alone and in blended combinations of all three fruit juice (2: 1: 2) was prepared using two different yeasts (Y4 and Y7) isolated from natural plain date palm juice and one standard Saccharomyces cerevisiae (MTCC-170) collected from IMTECH, Chandigar. Juices were extracted by using pectinase enzyme at 0.15-0.20 % of pulp. Changes in °Brix, titratable acid content, pH, total viable yeast count were recorded and rate of fermentation, sugar use efficiency were determined at every 24-hour interval up to the completion (6 days after inoculation) of fermentation. Considering all the quality parameter as well as fermentation efficiency, yeast isolate Y7 was found superior followed by Y4 as fermenting agent and pineapple juice as sole substrate found to be the most suitable medium for production of wine followed by fruit juice blending. In interpreting the efficacy of fruit and yeast in combination, pineapple juice inoculated with Y7 found to be the best in reducing the degree Brix to its lowest from initial 24 degree.

  5. DNA sequence analysis of newly formed telomeres in yeast.

    Science.gov (United States)

    Wang, S S; Pluta, A F; Zakian, V A

    1989-01-01

    A plasmid can be maintained in linear form in baker's yeast if it bears telomeric sequences at each end. Linear plasmids bearing cloned telomeric C4A4 repeats at one end (test end) and a natural DNA terminus with approximately 300 bps of C4A2 repeats at the other or control end were introduced by transformation into yeast. Test-end termini of 28 to 112 bps supported telomere formation. During telomere formation, C4A2 repeats were often transferred to test-end termini. To determine in greater detail the fate of test-end sequences on these plasmids after propagation in yeast, test-end telomeres were subcloned into E. coli and sequenced. DNA sequencing established a number of points about the molecular events involved in telomere formation in yeast. The results suggest that there are at least two mechanisms for telomere formation in yeast. One is mediated by a recombination event that requires neither a long stretch of homology nor the RAD52 gene product. The other mechanism is by addition of C1-3A repeats to the termini of linear DNA molecules. The telomeric sequence required to support C1-3A addition need not be at the very end of a molecule for telomere formation.

  6. Yeast-based microporous carbon materials for carbon dioxide capture.

    Science.gov (United States)

    Shen, Wenzhong; He, Yue; Zhang, Shouchun; Li, Junfen; Fan, Weibin

    2012-07-01

    A hierarchical microporous carbon material with a Brunauer-Emmett-Teller surface area of 1348 m(2) g(-1) and a pore volume of 0.67 cm(3) g(-1) was prepared from yeast through chemical activation with potassium hydroxide. This type of material contains large numbers of nitrogen-containing groups (nitrogen content >5.3 wt%), and, consequently, basic sites. As a result, this material shows a faster adsorption rate and a higher adsorption capacity of CO(2) than the material obtained by directly carbonizing yeast under the same conditions. The difference is more pronounced in the presence of N(2) or H(2)O, showing that chemical activation of discarded yeast with potassium hydroxide could afford high-performance microporous carbon materials for the capture of CO(2).

  7. Patagonian wines: the selection of an indigenous yeast starter.

    Science.gov (United States)

    Lopes, Christian A; Rodríguez, María E; Sangorrín, Marcela; Querol, Amparo; Caballero, Adriana C

    2007-08-01

    The use of selected yeasts for winemaking has clear advantages over the traditional spontaneous fermentation. The aim of this study was to select an indigenous Saccharomyces cerevisiae yeast isolate in order to develop a regional North Patagonian red wine starter culture. A two-step selection protocol developed according to physiological, technological and ecological criteria based on killer interactions was used. Following this methodology, S. cerevisiae isolate MMf9 was selected among 32 indigenous yeasts previously characterized as belonging to different strains according to molecular patterns and killer biotype. This isolate showed interesting technological and qualitative features including high fermentative power and low volatile acidity production, low foam and low sulphide production, as well as relevant ecological characteristics such as resistance to all indigenous and commercial S. cerevisiae killer strains assayed. Red wines with differential volatile profiles and interesting enological features were obtained at laboratory scale by using this selected indigenous strain.

  8. Recombinant brewer's yeast strains suitable for accelerated brewing.

    Science.gov (United States)

    Suihko, M L; Blomqvist, K; Penttilä, M; Gisler, R; Knowles, J

    1990-06-01

    Four brewer's yeast strains carrying the alpha-ald gene of Klebsiella terrigena (ex. Aerobacter aerogenes) or of Enterobacter aerogenes on autonomously replicating plasmids were constructed. The alpha-ald genes were linked either to the ADC1 promoter or to the PGK1 promoter of yeast Saccharomyces cerevisiae. In pilot scale brewing (50 l) with three of these recombinant yeasts the formation of diacetyl in beer was so low during fermentation that lagering was not required. All other brewing properties of the strains were unaffected and the quality of finished beers was as good as that of finished beer prepared with the control strain. The total process time of beer production could therefore be reduced to 2 weeks, in contrast to about 5 weeks required in the conventional process.

  9. Discovery of a nucleocytoplasmic O-mannose glycoproteome in yeast

    DEFF Research Database (Denmark)

    Halim, Adnan; Larsen, Ida Signe Bohse; Neubert, Patrick;

    2015-01-01

    developed a sensitive lectin enrichment and mass spectrometry workflow for identification of the human O-linked mannose (O-Man) glycoproteome and used this to identify a pleothora of O-Man glycoproteins in human cell lines including the large family of cadherins and protocadherins. Here, we applied...... the workflow to yeast with the aim to characterize the yeast O-Man glycoproteome, and in doing so, we discovered hitherto unknown O-Man glycosites on nuclear, cytoplasmic, and mitochondrial proteins in S. cerevisiae and S. pombe. Such O-Man glycoproteins were not found in our analysis of human cell lines....... However, the type of yeast O-Man nucleocytoplasmic proteins and the localization of identified O-Man residues mirror that of the O-GlcNAc glycoproteome found in other eukaryotic cells, indicating that the two different types of O-glycosylations serve the same important biological functions. The discovery...

  10. Aroma formation by immobilized yeast cells in fermentation processes.

    Science.gov (United States)

    Nedović, V; Gibson, B; Mantzouridou, T F; Bugarski, B; Djordjević, V; Kalušević, A; Paraskevopoulou, A; Sandell, M; Šmogrovičová, D; Yilmaztekin, M

    2015-01-01

    Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale-up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes. Copyright © 2014 John Wiley & Sons, Ltd.

  11. Beginnings of microbiology and biochemistry: the contribution of yeast research.

    Science.gov (United States)

    Barnett, James A

    2003-03-01

    With improvements in microscopes early in the nineteenth century, yeasts were seen to be living organisms, although some famous scientists ridiculed the idea and their influence held back the development of microbiology. In the 1850s and 1860s, yeasts were established as microbes and responsible for alcoholic fermentation, and this led to the study of the rôle of bacteria in lactic and other fermentations, as well as bacterial pathogenicity. At this time, there were difficulties in distinguishing between the activities of microbes and of extracellular enzymes. Between 1884 and 1894, Emil Fischer's study of sugar utilization by yeasts generated an understanding of enzymic specificity and the nature of enzyme-substrate complexes.

  12. How to halve ploidy: lessons from budding yeast meiosis.

    Science.gov (United States)

    Kerr, Gary William; Sarkar, Sourav; Arumugam, Prakash

    2012-09-01

    Maintenance of ploidy in sexually reproducing organisms requires a specialized form of cell division called meiosis that generates genetically diverse haploid gametes from diploid germ cells. Meiotic cells halve their ploidy by undergoing two rounds of nuclear division (meiosis I and II) after a single round of DNA replication. Research in Saccharomyces cerevisiae (budding yeast) has shown that four major deviations from the mitotic cell cycle during meiosis are essential for halving ploidy. The deviations are (1) formation of a link between homologous chromosomes by crossover, (2) monopolar attachment of sister kinetochores during meiosis I, (3) protection of centromeric cohesion during meiosis I, and (4) suppression of DNA replication following exit from meiosis I. In this review we present the current understanding of the above four processes in budding yeast and examine the possible conservation of molecular mechanisms from yeast to humans.

  13. 'Killer' character of yeasts isolated from ethanolic fermentations

    Directory of Open Access Journals (Sweden)

    Ceccato-Antonini Sandra Regina

    1999-01-01

    Full Text Available The number of killer, neutral and sensitive yeasts was determined from strains isolated from substrates related to alcoholic fermentations. From 113 isolates, 24 showed killer activity against NCYC 1006 (standard sensitive strain, while 30 were sensitive to NCYC 738 (standard killer strain, and 59 had no reaction in assays at 25-27°C. Two wild yeast strains of Saccharomyces cerevisiae and one of Candida colliculosa were tested against 10 standard killer strains and one standard sensitive strain in a cell x cell and well-test assays at four different pHs. None of the isolates displayed strong killer activity or were sensitive to the standard strains. All belonged to the neutral type. It was concluded that although the number of killer strains was high, this character cannot be used to protect ethanol fermentation processes against yeast contaminants like those which form cell clusters.

  14. Sustained glycolytic oscillations in individual isolated yeast cells.

    Science.gov (United States)

    Gustavsson, Anna-Karin; van Niekerk, David D; Adiels, Caroline B; du Preez, Franco B; Goksör, Mattias; Snoep, Jacky L

    2012-08-01

    Yeast glycolytic oscillations have been studied since the 1950s in cell-free extracts and intact cells. For intact cells, sustained oscillations have so far only been observed at the population level, i.e. for synchronized cultures at high biomass concentrations. Using optical tweezers to position yeast cells in a microfluidic chamber, we were able to observe sustained oscillations in individual isolated cells. Using a detailed kinetic model for the cellular reactions, we simulated the heterogeneity in the response of the individual cells, assuming small differences in a single internal parameter. This is the first time that sustained limit-cycle oscillations have been demonstrated in isolated yeast cells. The mathematical model described here has been submitted to the JWS Online Cellular Systems Modelling Database and can be accessed at http://jjj.biochem.sun.ac.za/database/gustavsson/index.html free of charge. © 2012 The Authors Journal compilation © 2012 FEBS.

  15. Recent Taxonomic Developments with Candida and Other Opportunistic Yeasts.

    Science.gov (United States)

    Brandt, Mary E; Lockhart, Shawn R

    2012-09-01

    Increases in susceptible patient populations and advances in identification methods have resulted in the continued recognition of novel yeasts as agents of human infection. Most of these agents are members of the well-recognized genera Candida, Cryptococcus, Trichosporon, and Rhodotorula. Some of these agents are "cryptic species," members of species complexes, and may not be detectable using classical carbohydrate assimilation-based methods of yeast identification. Such species require DNA- or MALDI-based methods for correct identification, although sporadic isolates may not routinely require delineation to the individual species level. The coming end of the fungal taxonomy rules requiring separate names for sexual and asexual forms of the same fungus will hopefully allow greater clarity, as names for medically important yeast can now be based on the needs of the medical mycology community and the common goal of better communication between laboratory and clinician.

  16. Diversity and adaptive evolution of Saccharomyces wine yeast: a review.

    Science.gov (United States)

    Marsit, Souhir; Dequin, Sylvie

    2015-11-01

    Saccharomyces cerevisiae and related species, the main workhorses of wine fermentation, have been exposed to stressful conditions for millennia, potentially resulting in adaptive differentiation. As a result, wine yeasts have recently attracted considerable interest for studying the evolutionary effects of domestication. The widespread use of whole-genome sequencing during the last decade has provided new insights into the biodiversity, population structure, phylogeography and evolutionary history of wine yeasts. Comparisons between S. cerevisiae isolates from various origins have indicated that a variety of mechanisms, including heterozygosity, nucleotide and structural variations, introgressions, horizontal gene transfer and hybridization, contribute to the genetic and phenotypic diversity of S. cerevisiae. This review will summarize the current knowledge on the diversity and evolutionary history of wine yeasts, focusing on the domestication fingerprints identified in these strains.

  17. Dynamical Analysis of Protein Regulatory Network in Budding Yeast Nucleus

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Ting; JIA Xun

    2006-01-01

    @@ Recent progresses in the protein regulatory network of budding yeast Saccharomyces cerevisiae have provided a global picture of its protein network for further dynamical research. We simplify and modularize the protein regulatory networks in yeast nucleus, and study the dynamical properties of the core 37-node network by a Boolean network model, especially the evolution steps and final fixed points. Our simulation results show that the number of fixed points N(k) for a given size of the attraction basin k obeys a power-law distribution N(k)∝k-2.024. The yeast network is more similar to a scale-free network than a random network in the above dynamical properties.

  18. Yeast mating for combinatorial Fab library generation and surface display

    Energy Technology Data Exchange (ETDEWEB)

    Feldhaus, Jane M.; Lou, Jianlong; Coleman, James R.; Siegel, Robert W.; Marks, James D.; Feldhaus, Michael

    2004-04-23

    Yeast display of antibody fragments has proven to be an efficient and productive means for directed evolution of single chain Fv (scFv) antibodies for increased affinity and thermal stability, and more recently for the display and screening of a non-immune library. In this paper, we describe an elegant and simple method for constructing large combinatorial Fab libraries for display on the surface of Saccharomyces cerevisiae, from modestly sized, and easily constructed, heavy and light chain libraries. To this end, we have constructed a set of yeast strains and a two vector system for heavy chain and light chain surface display of Fab fragments with free native amino termini. Through yeast mating of the haploid libraries, a very large heterodimeric immune Fab library was displayed on the diploids and high affinity antigen specific Fabs were isolated from the library.

  19. [Adaptation of yeasts of the genus Debaryomyces to protocatechuic acid].

    Science.gov (United States)

    Karasevich, Iu N

    1980-01-01

    Among five yeast strains belonging to the genus Debaryomyces that were unable of utilizing aromatic compounds (phenols and hydroxybenzoic acids), three strains, viz. D. kloeckeri BKM-Y-1044, D. marama BKM-Y-100 and D. marama BKM-Y-2045, were adapted to protocatechuic acid. The adapted yeasts utilized protocatechuic acid if its concentration in the medium was 0.1%, but did not utilize it, or did at a very low rate, if the concentration of protocatechuic acid was decreased to 0.05%. The mechanism of adaptation is rare mutations occurring in succession, and the process takes therefore several months. The adaptation seems to be based on reversion of inactivated genes for enzymes involved in the preparative metabolism of protocatechuic acid. Three typical yeast species of the Debaryomyces genus are proposed (D. hansenii, D. kloeckeri and D. konokotinae) which include all of the Debaryomyces species and strains available at the Institute of Microbiology of the USSR Academy of Sciences.

  20. Genetic Analysis of Haploids from Industrial Strains of Baker's Yeast.

    Science.gov (United States)

    Oda, Y; Ouchi, K

    1989-07-01

    Strains of baker's yeast conventionally used by the baking industry in Japan were tested for the ability to sporulate and produce viable haploid spores. Three isolates which possessed the properties of baker's yeasts were obtained from single spores. Each strain was a haploid, and one of these strains, YOY34, was characterized. YOY34 fermented maltose and sucrose, but did not utilize galactose, unlike its parental strain. Genetic analysis showed that YOY34 carried two MAL genes, one functional and one cryptic; two SUC genes; and one defective gal gene. The genotype of YOY34 was identified as MATalpha MAL1 MAL3g SUC2 SUC4 gall. The MAL1 gene from this haploid was constitutively expressed, was dominant over other wild-type MAL tester genes, and gave a weak sucrose fermentation. YOY34 was suitable for both bakery products, like conventional baker's yeasts, and for genetic analysis, like laboratory strains.

  1. Antifungal chitinase against human pathogenic yeasts from Coprinellus congregatus.

    Science.gov (United States)

    Yoo, Yeeun; Choi, Hyoung T

    2014-05-01

    The inky cap, Coprinellus congregatus, produces mushrooms which become autolyzed rapidly to generate black liquid droplets, in which no cell wall is detected by microscopy. A chitinase (Chi2) which is synthesized during the autolytic phase of C. congregatus inhibits the growths of Candida albicans and Cryptococcus neoformans up to 10% at the concentration of 10 μg/ml, about 50% at concentration of 20 μg/ml, and up to 95% at the concentration of 70 μg/ml. Upon treatment these yeast cells are observed to be severely deformed, with the formation of large holes in the cell wall. The two yeast species show no growth inhibition at the concentration of 5 μg/ml, which means the minimum inhibitory concentrations for both yeast species are 10 μg/ml under these experimental conditions.

  2. QTL mapping of sake brewing characteristics of yeast.

    Science.gov (United States)

    Katou, Taku; Namise, Masahiro; Kitagaki, Hiroshi; Akao, Takeshi; Shimoi, Hitoshi

    2009-04-01

    A haploid sake yeast strain derived from the commercial diploid sake yeast strain Kyokai no. 7 showed better characteristics for sake brewing compared to the haploid laboratory yeast strain X2180-1B, including higher production of ethanol and aromatic components. A hybrid of these two strains showed intermediate characteristics in most cases. After sporulation of the hybrid strain, we obtained 100 haploid segregants of the hybrid. Small-scale sake brewing tests of these segregants showed a smooth continuous distribution of the sake brewing characteristics, suggesting that these traits are determined by multiple quantitative trait loci (QTLs). To examine these sake brewing characteristics at the genomic level, we performed QTL analysis of sake brewing characteristics using 142 DNA markers that showed heterogeneity between the two parental strains. As a result, we identified 25 significant QTLs involved in the specification of sake brewing characteristics such as ethanol fermentation and the production of aromatic components.

  3. Biomimetic Yeast Cell Typing—Application of QCMs

    Directory of Open Access Journals (Sweden)

    Franz L. Dickert

    2009-10-01

    Full Text Available Artificial antibodies represent a key factor in the generation of sensing systems for the selective detection of bioanalytes of variable sizes. With biomimetic surfaces, the important model organism Saccharomyces cerevisiae and several of its growth stages may be detected. Quartz crystal microbalances (QCM with 10 MHz fundamental frequency and coated with polymers imprinted with synchronized yeast cells are presented, which are able to detect duplex cells with high selectivity. Furthermore, a multichannel quartz crystal microbalance (MQCM was designed and optimized for the measurement in liquids. This one-chip system based on four-electrode geometry allows the simultaneous detection of four analytes and, thus, provides a monitoring system for biotechnology and process control. For further standardization of the method, synthetic stamps containing plastic yeast cells in different growth stages were produced and utilized for imprinting. Mass-sensitive measurements with such MIPs resulted in the same sensor characteristics as obtained for those imprinted with native yeast cells.

  4. Tryptophan distribution in yeast hexokinase isoenzyme B

    Energy Technology Data Exchange (ETDEWEB)

    Kramp, D.C.; Feldman, I.

    1978-01-01

    Titrations of the quenching of the tryptophan fluorescence of yeast hexokinase isoenzyme B by Cs/sup +/, I/sup -/ and glucose as quenchers, singly and in various combinations, have been performed at pH 5.5, 8.3, and 10.1 at 20/sup 0/C. The iodide and glucose titrations at pH 8.3 indicated that the four tryptophan residues of the monomer subunit can be classified as: (1) a highly accessible surface tryptophan (Trp-S/sub 1/); (2) a surface tryptophan (Trp-S/sub 2/) with restricted accessibility (possibly in a crevice); (3) a glucose-quenchable cleft tryptophan (Trp-G); and (4) a buried tryptophan (Trp-B) in the hydrophobic interior. The Stern-Volmer constants, k/sub I/, calculated for iodide quenching of the two surface residues at pH 8.3 are 22 and 3.3 M/sup -1/. The k/sub I/ value of Trp-G at this pH is iodide dependent, increasing from 1.2 to 1.4 M/sup -1/ as the iodide concentration increases from 0.1 to 0.65 M, probably because of iodide-induced alteration of the cleft structure. An iodide concentration above 0.65 M quenches Trp-B detectably, demonstrating that a high iodide concentration produces a large structural change in the isoenzyme. The percentages of the total 350 nm emission attributable to the individual tryptophan residues at pH 8.3 are 9, 22, 28, and 41%, for Trp-S/sub 1/, Trp-S/sub 2/, Trp-G, and Trp-B, respectively. At pH 5.5 even a low iodide concentration causes some quenching of Trp-B, especially in presence of saturating glucose. Glucose increases the iodide quenchability at this pH. At pH 10.1 glucose does not quench the tryptophan emission, and it does not influence the iodide-quenching action. However, at this high pH the k/sub 1/ of Trp-S/sub 1/ is reduced to the point where it is not resolvable from the k/sub I/ values of Trp-S/sub 2/ and Trp-G, even though the sum of the fractional fluorescence contributions of these three residues is the same as at pH 8.3.

  5. Trytophan distribution in yeast hexokinase isoenzyme B

    Energy Technology Data Exchange (ETDEWEB)

    Kramp, D.C.; Feldman, I.

    1978-01-01

    Titrations of quenching of tryptophan fluorescence of yeast hexokinase isoenzyme B by Cs/sup +/, I/sup -/ and glucose, singly and in various combinations, were performed at pH 5.5, 8.3, and 10.1 at 20/sup 0/C. The iodide and glucose titrations at pH 8.3 indicated the four tryptophan residues of the monomer subunit can be classified as: (1) a highly accessible surface tryptophan (Trp-S/sub 1/); (2) a surface tryptophan (Trp-S/sub 2/) with restricted accessibility; (3) a glucose-quenchable cleft tryptophan (Trp-G); and (4) a buried tryptophan (Trp-B) in the hydrophobic interior. The Stern-Volmer constants, k/sub I/, for iodide quenching of the two surface residues at pH 8.3 are 22 and 3.3 M/sup -1/. The k/sub I/ value of Trp-G at this pH is iodide dependent, increasing from 1.2 to 1.4 M/sup -1/ as the iodide concentration increases from 0.1 to 0.65 M, probably because of iodide-induced alteration of the cleft structure. An iodide concentration above 0.65 M quenches Trp-B detectably, demonstrating a large structural change in the isoenzyme. The 350 nm emission attributable to the individual tryptophan residues at pH 8.3 are 9, 22, 28, and 41%, for Trp-S/sub 1/, Trp-S/sub 2/, Trp-G, and Trp-B, respectively. These results agree qualitatively with results deduced from the wavelength dependence of glucose quenching. I/sup -/ and glucose bind non-competitively to produce a synergistic enhancement of quenching of the cleft tryptophan fluorescence. At pH 5.5 even a low iodide concentration causes some quenching of Trp-B, especially in presence of saturating glucose. At pH 10.1 glucose does not quench the tryptophan emission nor influence the iodide-quenching action. However, at this pH the k/sub 1/ of Trp-S/sub 1/ is reduced to the point where it is not resolvable from the k/sub I/ values of Trp-S/sub 2/ and Trp-G, even though the sum of the fractional fluorescence contributions of these three residues is the same as at pH 8.3.

  6. Crossflow microfiltration of yeast suspensions in tubular filters.

    Science.gov (United States)

    Redkar, S G; Davis, R H

    1993-01-01

    Crossflow microfiltration experiments were performed on yeast suspensions through 0.2-microns pore size ceramic and polypropylene tubes at various operating conditions. The initial transient flux decline follows dead-end filtration theory, with the membrane resistance determined from the initial flux and the specific cake resistance determined from the rate of flux decline due to cake buildup. For long times, the observed fluxes reach steady or nearly steady values, presumably as a result of the cake growth being arrested by the shear exerted at its surface. The steady-state fluxes increase with increasing shear rate and decreasing feed concentration, and they are nearly independent of transmembrane pressure. The steady-state fluxes for unwashed yeast in deionized water or fermentation media are typically 2-4 times lower than those predicted by a model based on the properties of nonadhesive, rigid spheres undergoing shear-induced back-diffusion. In contrast, the steady-state fluxes observed for washed yeast cells in deionized water are only 10-30% below the predicted values. The washed yeast cells also exhibited specific cake resistances that are an order of magnitude lower than those for the unwashed yeast. The differences are due to the presence of extracellular proteins and other macromolecules in the unwashed yeast suspensions. These biopolymers cause higher cell adhesion and resistance in the cake layer, so that the cells at the top edge are not free to diffuse away. This is manifested as a concentration jump from the edge of the cake layer to the sheared suspension adjacent to it.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Concentration measurement of yeast suspensions using high frequency ultrasound backscattering.

    Science.gov (United States)

    Elvira, Luis; Vera, Pedro; Cañadas, Francisco Jesús; Shukla, Shiva Kant; Montero, Francisco

    2016-01-01

    This work proposes the use of an ultrasound based technique to measure the concentration of yeasts in liquid suspension. This measurement was achieved by the detection and quantification of ultrasonic echoes backscattered by the cells. More specifically, the technique was applied to the detection and quantification of Saccharomyces cerevisiae. A theoretical approach was proposed to get the average density and sound speed of the yeasts, which were found to be 1116 kg/m(3) and 1679 m/s, respectively. These parameters were needed to model the waves backscattered by each single cell. A pulse-echo arrangement working around 50 MHz, being able to detect echoes from single yeasts was used to characterize experimentally yeast solutions from 10(2) to 10(7)cells/ml. The Non-negative Matrix Factorization denoising technique was applied for data analysis. This technique required a previous learning of the spectral patterns of the echoes reflected from yeasts in solution and the base noise from the liquid medium. Comparison between pulse correlation (without denoising) and theoretical and experimental pattern learning was made to select the best signal processing. A linear relation between ultrasound output and concentration was obtained with correlation coefficient R(2)=0.996 for the experimental learning. Concentrations from 10(4) to 10(7)cells/ml were detected above the base noise. These results show the viability of using the ultrasound backscattering technique to detect yeasts and measure their concentration in liquid cultures, improving the sensitivity obtained using spectrophotometric methods by one order of magnitude.

  8. Yeast strains as potential aroma enhancers in dry fermented sausages.

    Science.gov (United States)

    Flores, Mónica; Corral, Sara; Cano-García, Liliana; Salvador, Ana; Belloch, Carmela

    2015-11-06

    Actual healthy trends produce changes in the sensory characteristics of dry fermented sausages therefore, new strategies are needed to enhance their aroma. In particular, a reduction in the aroma characteristics was observed in reduced fat and salt dry sausages. In terms of aroma enhancing, generally coagulase-negative cocci were selected as the most important group from the endogenous microbiota in the production of flavour compounds. Among the volatile compounds analysed in dry sausages, ester compounds contribute to fruity aroma notes associated with high acceptance of traditional dry sausages. However, the origin of ester compounds in traditional dry sausages can be due to other microorganisms as lactic acid bacteria, yeast and moulds. Yeast contribution in dry fermented sausages was investigated with opposite results attributed to low yeast survival or low activity during processing. Generally, they affect sausage colour and flavour by their oxygen-scavenging and lipolytic activities in addition to, their ability to catabolize fermentation products such as lactate increasing the pH and contributing to less tangy and more aromatic sausages. Recently, the isolation and characterization of yeast from traditional dry fermented sausages made possible the selection of those with ability to produce aroma active compounds. Molecular methods were used for genetic typing of the isolated yeasts whereas their ability to produce aroma compounds was tested in different systems such as in culture media, in model systems and finally on dry fermented sausages. The results revealed that the appropriate selection of yeast strains with aroma potential may be used to improve the sensory characteristics of reformulated fermented sausages.

  9. Genotyping 1000 yeast strains by next-generation sequencing

    Directory of Open Access Journals (Sweden)

    Wilkening Stefan

    2013-02-01

    Full Text Available Abstract Background The throughput of next-generation sequencing machines has increased dramatically over the last few years; yet the cost and time for library preparation have not changed proportionally, thus representing the main bottleneck for sequencing large numbers of samples. Here we present an economical, high-throughput library preparation method for the Illumina platform, comprising a 96-well based method for DNA isolation for yeast cells, a low-cost DNA shearing alternative, and adapter ligation using heat inactivation of enzymes instead of bead cleanups. Results Up to 384 whole-genome libraries can be prepared from yeast cells in one week using this method, for less than 15 euros per sample. We demonstrate the robustness of this protocol by sequencing over 1000 yeast genomes at ~30x coverage. The sequence information from 768 yeast segregants derived from two divergent S. cerevisiae strains was used to generate a meiotic recombination map at unprecedented resolution. Comparisons to other datasets indicate a high conservation of recombination at a chromosome-wide scale, but differences at the local scale. Additionally, we detected a high degree of aneuploidy (3.6% by examining the sequencing coverage in these segregants. Differences in allele frequency allowed us to attribute instances of aneuploidy to gains of chromosomes during meiosis or mitosis, both of which showed a strong tendency to missegregate specific chromosomes. Conclusions Here we present a high throughput workflow to sequence genomes of large number of yeast strains at a low price. We have used this workflow to obtain recombination and aneuploidy data from hundreds of segregants, which can serve as a foundation for future studies of linkage, recombination, and chromosomal aberrations in yeast and higher eukaryotes.

  10. Yeast identification in floral nectar of Mimulus aurantiacus (Invited)

    Science.gov (United States)

    Kyauk, C.; Belisle, M.; Fukami, T.

    2009-12-01

    Nectar is such a sugar-rich resource that serves as a natural habitat in which microbes thrive. As a result, yeasts arrive to nectar on the bodies of pollinators such as hummingbirds and bees. Yeasts use the sugar in nectar for their own needs when introduced. This research focuses on the identification of different types of yeast that are found in the nectar of Mimulus aurantiacus (commonly known as sticky monkey-flower). Unopened Mimulus aurantiacus flower buds were tagged at Jasper Ridge and bagged three days later. Floral nectar was then extracted and plated on potato dextrose agar. Colonies on the plates were isolated and DNA was extracted from each sample using QIAGEN DNeasy Plant Mini Kit. The DNA was amplified through PCR and ran through gel electrophoresis. The PCR product was used to clone the nectar samples into an E.coli vector. Finally, a phylogenetic tree was created by BLAST searching sequences in GenBank using the Internal Transcribed Space (ITS) locus. It was found that 18 of the 50 identified species were Candida magnifica, 14 was Candida rancensis, 6 were Crytococcus albidus and there were 3 or less of the following: Starmella bombicola, Candida floricola, Aureobasidium pullulans, Pichia kluyvera, Metschnikowa cibodaserisis, Rhodotorua colostri, and Malassezia globosa. The low diversity of the yeast could have been due to several factors: time of collection, demographics of Jasper Ridge, low variety of pollinators, and sugar concentration of the nectar. The results of this study serve as a necessary first step for a recently started research project on ecological interactions between plants, pollinators, and nectar-living yeast. More generally, this research studies the use of the nectar-living yeast community as a natural microcosm for addressing basic questions about the role of dispersal and competitive and facilitative interactions in ecological succession.

  11. Uranium bioprecipitation mediated by yeasts utilizing organic phosphorus substrates.

    Science.gov (United States)

    Liang, Xinjin; Csetenyi, Laszlo; Gadd, Geoffrey Michael

    2016-06-01

    In this research, we have demonstrated the ability of several yeast species to mediate U(VI) biomineralization through uranium phosphate biomineral formation when utilizing an organic source of phosphorus (glycerol 2-phosphate disodium salt hydrate (C3H7Na2O6P·xH2O (G2P)) or phytic acid sodium salt hydrate (C6H18O24P6·xNa(+)·yH2O (PyA))) in the presence of soluble UO2(NO3)2. The formation of meta-ankoleite (K2(UO2)2(PO4)2·6(H2O)), chernikovite ((H3O)2(UO2)2(PO4)2·6(H2O)), bassetite (Fe(++)(UO2)2(PO4)2·8(H2O)), and uramphite ((NH4)(UO2)(PO4)·3(H2O)) on cell surfaces was confirmed by X-ray diffraction in yeasts grown in a defined liquid medium amended with uranium and an organic phosphorus source, as well as in yeasts pre-grown in organic phosphorus-containing media and then subsequently exposed to UO2(NO3)2. The resulting minerals depended on the yeast species as well as physico-chemical conditions. The results obtained in this study demonstrate that phosphatase-mediated uranium biomineralization can occur in yeasts supplied with an organic phosphate substrate as sole source of phosphorus. Further understanding of yeast interactions with uranium may be relevant to development of potential treatment methods for uranium waste and utilization of organic phosphate sources and for prediction of microbial impacts on the fate of uranium in the environment.

  12. Inventions on baker's yeast storage and activation at the bakery plant.

    Science.gov (United States)

    Gélinas, Pierre

    2010-01-01

    Baker's yeast is the gas-forming ingredient in bakery products. Methods have been invented to properly handle baker's yeast and optimize its activity at the bakery plant. Over the years, incentives for inventions on yeast storage and activation have greatly changed depending on trends in the baking industry. For example, retailer's devices for cutting bulk pressed yeast and techniques for activating dry yeast have now lost their importance. Review of patents for invention indicates that activation of baker's yeast activity has been a very important issue for bakers, for example, with baking ingredients called yeast foods. In the recent years and especially for highly automated bakeries, interest has moved to equipments and processes for optimized storage of liquid cream yeast to thoroughly control dough fermentation and bread quality.

  13. A proton-translocating adenosine triphosphatase is associated with the peroxisomal membrane of yeasts

    NARCIS (Netherlands)

    Douma, A.C.; Veenhuis, M.; Sulter, G.J.; Harder, W.

    1987-01-01

    The association of an ATPase with the yeast peroxisomal membrane was established by both biochemical and cytochemical procedures. Peroxisomes were purified from protoplast homogenates of the methanol-grown yeast Hansenula polymorpha by differential and sucrose gradient centrifugation. Biochemical an

  14. In vivo unnatural amino acid expression in the methylotrophic yeast Pichia pastoris

    Energy Technology Data Exchange (ETDEWEB)

    Young, Travis; Schultz, Peter G.

    2017-08-15

    The invention provides orthogonal translation systems for the production of polypeptides comprising unnatural amino acids in methylotrophic yeast such as Pichia pastoris. Methods for producing polypeptides comprising unnatural amino acids in methylotrophic yeast such as Pichia pastoris are also provided.

  15. In vivo unnatural amino acid expression in the methylotrophic yeast Pichia pastoris

    Energy Technology Data Exchange (ETDEWEB)

    Young, Travis [San Diego, CA; Schultz, Peter G [La Jolla, CA

    2014-02-11

    The invention provides orthogonal translation systems for the production of polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris. Methods for producing polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris are also provided.

  16. Evaluation of yeast strains for production of fuel ethanol from biomass hydrolysates

    Science.gov (United States)

    Robust industrial yeast strains are needed for profitable production of fuel ethanol from mixed biomass waste. USDA, ARS, NCAUR, RPT has been evaluating ethanol-producing yeasts, including Saccharomyces cerevisiae, engineered GMAX Saccharomyces cerevisiae, irradiated Kluyveromyces marxianus, and Pi...

  17. Nonlinear Dielectric Properties of Yeast Cells Cultured in Different Environmental Conditions

    Science.gov (United States)

    Kawanishi, Gomon; Fukuda, Naoki; Muraji, Masafumi

    The harmonics of the electric current through yeast suspensions, the nonlinear dielectric properties of yeast cells, have particular patterns according to the biological activity of the cells and the measurement of these patterns is a technique for determining the activity of living cells. The concentration of glucose and oxygen in yeast culture medium influences the manifestation of fermentation or respiration of yeast cells. Measurements were made with yeast cells (Saccharomyces cerevisiae) cultured aerobically and anaerobically in sufficient glucose concentration, aerobic fermentation and anaerobic fermentation, and aerobically in limited glucose concentration, respiration. The results showed that the harmonics were barely apparent for yeast cells in aerobic fermentation and respiratory; however, cells in the anaerobic fermentation displayed substantial third and fifth harmonics. We can say that environmental condition affects the yeast cells' nonlinear properties, from another viewpoint, the measurements of the nonlinear properties are available to determine the activity of yeast cells adjusted to the conditions of their cultivation.

  18. Assessing genetic diversity among Brettanomyces yeasts by DNA fingerprinting and whole-genome sequencing

    National Research Council Canada - National Science Library

    Crauwels, Sam; Zhu, Bo; Steensels, Jan; Busschaert, Pieter; De Samblanx, Gorik; Marchal, Kathleen; Willems, Kris A; Verstrepen, Kevin J; Lievens, Bart

    2014-01-01

    Brettanomyces yeasts, with the species Brettanomyces (Dekkera) bruxellensis being the most important one, are generally reported to be spoilage yeasts in the beer and wine industry due to the production of phenolic off flavors. However, B...

  19. Schizosaccharomyces pombe, the Principal Subject of Fission Yeast Genetics

    DEFF Research Database (Denmark)

    Egel, Richard

    2013-01-01

    Schizosaccharomyces pombe is a primitive ascomycetous fungus, also known as fission yeast. It has been extensively used in general and molecular genetics, and its genome is fully sequenced. It is considered a very useful model organism for experimental research on fundamental properties of eukary......Schizosaccharomyces pombe is a primitive ascomycetous fungus, also known as fission yeast. It has been extensively used in general and molecular genetics, and its genome is fully sequenced. It is considered a very useful model organism for experimental research on fundamental properties...

  20. Enzymes of yeast polyphosphate metabolism: structure, enzymology and biological roles.

    Science.gov (United States)

    Gerasimaitė, Rūta; Mayer, Andreas

    2016-02-01

    Inorganic polyphosphate (polyP) is found in all living organisms. The known polyP functions in eukaryotes range from osmoregulation and virulence in parasitic protozoa to modulating blood coagulation, inflammation, bone mineralization and cellular signalling in mammals. However mechanisms of regulation and even the identity of involved proteins in many cases remain obscure. Most of the insights obtained so far stem from studies in the yeast Saccharomyces cerevisiae. Here, we provide a short overview of the properties and functions of known yeast polyP metabolism enzymes and discuss future directions for polyP research.

  1. [Characteristic of the yeast isolated from patients with leukaemia].

    Science.gov (United States)

    Fedorovskaia, E A; Rybal'skaia, A P; Skachkova, N K; Mel'nik, E A; Nemirovskaia, L N; Nagornaia, S S; Babich, T V; Polishchuk, L V

    2008-01-01

    It has been shown that biotopes of upper respiratory system and intestine were contaminated with yeast in 44.6% of patients with leukaemia (of 112 examined ones). Their quantity exceeds the boundary value for practically healthy people and is > or = 10(2) KOE/ml in the nasal activity and fauces and leucemia the mycotic complications are mainly caused by anamorphous yeast of ascomycetic affinity. Candida albicans, as well as C. glabrata, C. rugosa and Candida sp. play the leading role. The Candida genus species are mainly sensitive to amphotericine B, clotrisamol and nistatin.

  2. LIPASES PRODUCED BY YEASTS: POWERFUL BIOCATALYSTS FOR INDUSTRIAL PURPOSES

    Directory of Open Access Journals (Sweden)

    Luiza Lux Lock

    2007-12-01

    Full Text Available The term “lipolytic enzymes” refers to the lipases and carboxylic ester hydrolases. Lipase production is widespread among yeasts, but few are capable of producing lipases with interesting characteristics and in sufficient amounts to be industrially useful. The literature concerning lipases produced by Candida rugosa, Yarrowia (Candida lipolytica, Candida antarctica and other emerging lipase-producing yeasts is reviewed. The use of recombinant lipases is discussed, with emphasis on the utilization of heterologous expression systems and design of chimeras. Finally, the three approaches that aim the improvement of lipase production or the modification of the substrate selectivity of the enzyme (medium engineering, biocatalyst engineering, and protein engineering are discussed.

  3. A Survey of Study on Lactase Isolated from Yeast

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ 1 General situation of lactase distributionLactase ( β-D-galactosidase EC 3. 2. 1. 23 )[1] generally exists in microorganism and many kinds of animals and plants like almond,apricot,peach,soybean,coffee bean and snail. In microorganism category,mold and yeast can produce this enzyme.Due to the fact that yeast is safe,unvirulent and easy to culture,using it as a source of enzyme seems relatively ideal.Thus,a lot of studies corresponding to this field has been conducted[2].

  4. Global metabolite analysis of yeast: evaluation of sample preparation methods

    DEFF Research Database (Denmark)

    Villas-Bôas, Silas Granato; Højer-Pedersen, Jesper; Åkesson, Mats Fredrik;

    2005-01-01

    , which is the analysis of a large number of metabolites with very diverse chemical and physical properties. This work reports the leakage of intracellular metabolites observed during quenching yeast cells with cold methanol solution, the efficacy of six different methods for the extraction...... of intracellular metabolites, and the losses noticed during sample concentration by lyophilization and solvent evaporation. A more reliable procedure is suggested for quenching yeast cells with cold methanol solution, followed by extraction of intracellular metabolites by pure methanol. The method can be combined...

  5. Random Boolean network models and the yeast transcriptional network

    Science.gov (United States)

    Kauffman, Stuart; Peterson, Carsten; Samuelsson, Björn; Troein, Carl

    2003-12-01

    The recently measured yeast transcriptional network is analyzed in terms of simplified Boolean network models, with the aim of determining feasible rule structures, given the requirement of stable solutions of the generated Boolean networks. We find that for ensembles of generated models, those with canalyzing Boolean rules are remarkably stable, whereas those with random Boolean rules are only marginally stable. Furthermore, substantial parts of the generated networks are frozen, in the sense that they reach the same state regardless of initial state. Thus, our ensemble approach suggests that the yeast network shows highly ordered dynamics.

  6. New type of postirradiation recovery of diploid yeast Saccharomyces cerevisae

    Energy Technology Data Exchange (ETDEWEB)

    Glazunov, A.V.; Kapul' tsevich, Yu.G. (Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Genetiki i Selektsii Promyshlennykh Mikroorganizmov, Moscow (USSR))

    It was shown that the survival of diploid yeast Saccharomyces cerevisiae plated on the nutrient medium containing 8% NaCl rapidly increases with time of postirradiation keeping the cells in water at 28 deg C. The process is completed in 30-40 min. One fails to observe this phenomenon with the exposed cells plated on a standard culture medium for, in this case, the recovery has been fully completed before the first postirradiation division occurs. Haploid yeast Saccharomyces cerevisiae and diploid Pichia pinus are not capable of ''rapid'' repair of the studied type.

  7. Oxidative stress response pathways: Fission yeast as archetype

    DEFF Research Database (Denmark)

    Papadakis, Manos A.; Workman, Christopher

    2015-01-01

    the transcriptional response of fission yeast cells to elevated levels of hydrogen peroxide. Particular attention is paid to the mechanisms that yeast cells employ to promote cell survival in conditions of intermediate and acute oxidative stress. The role of the Sty1/Spc1/Phh1 mitogen-activated protein kinase......Schizosaccharomyces pombe is a popular model eukaryotic organism to study diverse aspects of mammalian biology, including responses to cellular stress triggered by redox imbalances within its compartments. The review considers the current knowledge on the signaling pathways that govern...

  8. Synthetic biology for engineering acetyl coenzyme a metabolism in yeast

    DEFF Research Database (Denmark)

    Nielsen, Jens

    2014-01-01

    The yeast Saccharomyces cerevisiae is a widely used cell factory for the production of fuels, chemicals, and pharmaceuticals. The use of this cell factory for cost-efficient production of novel fuels and chemicals requires high yields and low by-product production. Many industrially interesting...... chemicals are biosynthesized from acetyl coenzyme A (acetyl-CoA), which serves as a central precursor metabolite in yeast. To ensure high yields in production of these chemicals, it is necessary to engineer the central carbon metabolism so that ethanol production is minimized (or eliminated) and acetyl...

  9. Nile Red Staining of Neutral Lipids in Yeast.

    Science.gov (United States)

    Rostron, Kerry Ann; Lawrence, Clare Louise

    2017-01-01

    Determination of cellular neutral lipid levels in yeast is important for both the biotechnology industry and biomedical research. However, many of the currently available methods are labor intensive and time consuming. Here we describe a rapid and repeatable method for the detection of neutral lipids, which can be utilized in both oleaginous and non-oleaginous yeast species. The method utilizes the fluorescent dye, Nile red, which enables neutral lipid levels to either be visualized via microscopy or quantified using a 96-well plate assay.

  10. Fission Yeast Model Study for Dissection of TSC Pathway

    Science.gov (United States)

    2010-04-01

    have also generated two mutants, rhb1-DA4 and rhb1-DA8. In fission yeast, two events, induction of a meiosis initiating gene mei2+ and cell division... meiosis are less induced. Under the same condition, retrotransposons, G1-cyclin (pas1+) and inv1+ are more induced. We have also demonstrated that...responsible for rhb1-DA4, and Q52R I76F within the switch II domain for rhb1-DA8. In fission yeast, two events, induction of a meiosis initiating

  11. Fluid-phase endocytosis in yeasts other than Saccharomyces cerevisiae.

    Science.gov (United States)

    Fernandez, N; Puente, P; Leal, F

    1990-05-01

    A FITC-dextran internalization assay with Saccharomyces cerevisiae as positive control was used to determine whether fluid-phase endocytosis is a general characteristic of yeasts. Schizosaccharomyces pombe, Pichia polymorpha, Kluyveromyces phaseolosporus, Yarrowia lipolytica and Candida albicans were clearly positive, whereas results obtained with Debaryomyces marama were inconclusive. In all cases internalized FITC-dextran was found to be localized in the vacuoles and the process was always time- and temperature-dependent. Lower eucaryotes, particularly yeasts, appear to have the ability to incorporate substances from the extracellular medium through fluid-phase endocytosis.

  12. Oxidative stress response pathways: Fission yeast as archetype.

    Science.gov (United States)

    Papadakis, Manos A; Workman, Christopher T

    2015-01-01

    Schizosaccharomyces pombe is a popular model eukaryotic organism to study diverse aspects of mammalian biology, including responses to cellular stress triggered by redox imbalances within its compartments. The review considers the current knowledge on the signaling pathways that govern the transcriptional response of fission yeast cells to elevated levels of hydrogen peroxide. Particular attention is paid to the mechanisms that yeast cells employ to promote cell survival in conditions of intermediate and acute oxidative stress. The role of the Sty1/Spc1/Phh1 mitogen-activated protein kinase in regulating gene expression at multiple levels is discussed in detail.

  13. Utilization of hexamethylenetetramine (urotropine) by bacteria and yeasts.

    Science.gov (United States)

    Middelhoven, Wouter J; van Doesburg, Wim

    2007-02-01

    A slow growing bacterial population able to utilize hexamethylelenetetramine (urotropine) as sole source of carbon, nitrogen and energy was isolated from soil. From this crude enrichment culture two bacteria were isolated and identified as Brevundimonas diminuta and a Phyllobacterium sp. by sequencing of 16S ribosomal DNA. These bacteria also grew on urotropine but at a lower rate than the enrichment culture. Addition of glucose to the latter resulted in growth of some yeasts that overgrew the bacteria. Assimilation of urotropine as sole nitrogen source is very common among yeasts, 46 out of 60 species tested showed this characteristic.

  14. Detection of myosin immunoanalogue in the yeast Candida albicans.

    Science.gov (United States)

    Ghazali, M; Rodier, M H; el Moudni, B; Quellard, N; Jacquemin, J L

    1995-06-01

    Detection and localization of myosin immunoanalogue protein in the yeast Candida albicans were achieved by immunoblotting, indirect immunofluorescence assay, and immunoelectron microscopy. A polypeptide with an M(r) about 110,000, from cytosolic extract and insoluble fraction in the corresponding membrane pellet, was reacted with polyclonal and monoclonal antibodies raised against vertebrate muscle myosin. This protein was located by immunofluorescence and immunoelectron microscopy in the cell cortex along the plasmalemma, in the cytoplasm, and in the septum corresponding to bud scar region situated between the yeast-mother cell and the bud.

  15. [Whey as a substrate for obtaining an edible yeast].

    Science.gov (United States)

    Terra, N N

    1976-01-01

    Using a fermentative process of whey through Kluyveromyces fragilys, Jörgensen, the Author prepared two edible products: Biomass I (yeast) and Biomass II (yeast plus protein of whey). Biomass I offered 53% of protein, and the yield was 22,3 g/1 whey. Biomass II, 62% of protein and yield of 27,7 g/1 whey. The test of food efficiency for Biomass II was similar to that presented by casein; the protein eficiency ratio at the level of 5% was the same, both for Biomass I and II. More research is needed specially to determine the economical convenience of the process.

  16. How do yeast cells become tolerant to high ethanol concentrations?

    DEFF Research Database (Denmark)

    Snoek, Tim; Verstrepen, Kevin J.; Voordeckers, Karin

    2016-01-01

    The brewer’s yeast Saccharomyces cerevisiae displays a much higher ethanol tolerance compared to most other organisms, and it is therefore commonly used for the industrial production of bioethanol and alcoholic beverages. However, the genetic determinants underlying this yeast’s exceptional ethanol...... tolerance have proven difficult to elucidate. In this perspective, we discuss how different types of experiments have contributed to our understanding of the toxic effects of ethanol and the mechanisms and complex genetics underlying ethanol tolerance. In a second part, we summarize the different routes...... and challenges involved in obtaining superior industrial yeasts with improved ethanol tolerance....

  17. Database Description - Yeast Interacting Proteins Database | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available Yeast Interacting Proteins Database Database Description General information of database Database name Yeast... Interacting Proteins Database Alternative name - Creator Creator Name: Takashi Ito* Creator Affiliation: Di...-4-7136-3989 FAX: +81-4-7136-3979 E-mail : Database classification Metabolic and Signaling Pathways - Protei...n-protein interactions Organism Taxonomy Name: Saccharomyces cerevisiae Taxonomy ID: 4932 Database descripti...ive yeast two-hybrid analysis of budding yeast proteins. Features and manner of utilization of database Prot

  18. Yeast succession in the Amazon fruit Parahancornia amapa as resource partitioning among Drosophila spp.

    OpenAIRE

    MORAIS, PB; MARTINS, MB; Klaczko, LB; MENDONCAHAGLER, LC; HAGLER, AN

    1995-01-01

    The succession of yeasts colonizing the fallen ripe amapa fruit, from Parahancornia. amapa, aas examined. The occupation of the substrate depended on both the competitive interactions of yeast species, such as the production of killer toxins, and the selective dispersion by the drosophilid guild of the amapa fruit. The yeast community associated with this Amazon fruit differed from those isolated from other fruits in the same forest. The physiological profile of these yeasts was mostly restri...

  19. Diversity and the role of yeast in spontaneous cocoa bean fermentation from Southeast Sulawesi, Indonesia

    OpenAIRE

    JAMILI; NUR ARFA YANTI; PRIMA ENDANG SUSILOWATI

    2016-01-01

    Abstract. Jamili, Yanti NA, Susilowati PE. 2016. Diversity and the role of yeast in spontaneous cocoa bean fermentation from Southeast Sulawesi, Indonesia. Biodiversitas 17: 90-95. Yeast is one of the microbial group which is role in the process of cocoa spontaneously fermentation. The objective of this study was to determinate and to know the diversity of yeast that role on cocoa bean fermentation. Yeast was isolated by pour plate method from cocoa bean that was naturally fermented by a coco...

  20. Use of high-ethanol-resistant yeast isolates from Nigerian palm wine in lager beer brewing.

    Science.gov (United States)

    Agu, R C; Anyanwu, T U; Onwumelu, A H

    1993-11-01

    High-ethanol-resistant yeasts, characterized as Saccharomyces sp., were isolated from Nigerian palm wine with added sucrose for high gravity brewing. The yeast isolates that survived the highest ethanol production were used to ferment brewery wort and produced 8.2 to 8.5% (v/v) ethanol; values almost double that of the control yeast from a local brewery.

  1. Experiments on the formation of carboxylase and thiamine pyrophosphate in living bakers' yeast

    NARCIS (Netherlands)

    Leijnse, B.; Terpstra, W.

    1951-01-01

    The formation of carboxylase by living bakers' yeast was demonstrated upon incubation of the yeast with either thiamine or 2-methyl-4-amino-5-ethoxymethylpyrimidine, in the presence and in the absence of glucose. Carboxylase is also formed upon incubation of the yeast with NH4 sulfate and glucose. I

  2. Whole-Genome Sequence of Starmerella bacillaris PAS13, a Nonconventional Enological Yeast with Antifungal Activity.

    Science.gov (United States)

    Lemos Junior, Wilson José Fernandes; Treu, Laura; da Silva Duarte, Vinícius; Carlot, Milena; Nadai, Chiara; Campanaro, Stefano; Giacomini, Alessio; Corich, Viviana

    2017-08-10

    Starmerella bacillaris is a fermentative yeast commonly found in vineyards. Here, we present the draft genome sequence of S. bacillaris PAS13, a nonconventional enological yeast with a potential role as a biocontrol agent. This gene sequence will provide insights into the genetic basis of yeast activity against gray mold disease (Botrytis cinerea). Copyright © 2017 Lemos Junior et al.

  3. Can phyllosphere yeast explain the effect of scab fungicides on russeting of Elstar Apples?

    NARCIS (Netherlands)

    Gildemacher, P.R.; Heijne, B.; Houbraken, J.; Vromans, T.; Hoekstra, E.S.; Boekhout, T.

    2004-01-01

    In 1999 and 2000, the effects of scab fungicides on yeast composition and russeting of Elstar apples were assessed. Yeast composition of fungicide-treated and untreated young apple fruit with or without russet symptoms was investigated and enzyme activity of the yeasts was studied. Cryptococcus albi

  4. Independent Evolution of Winner Traits without Whole Genome Duplication in Dekkera Yeasts.

    Directory of Open Access Journals (Sweden)

    Yi-Cheng Guo

    Full Text Available Dekkera yeasts have often been considered as alternative sources of ethanol production that could compete with S. cerevisiae. The two lineages of yeasts independently evolved traits that include high glucose and ethanol tolerance, aerobic fermentation, and a rapid ethanol fermentation rate. The Saccharomyces yeasts attained these traits mainly through whole genome duplication approximately 100 million years ago (Mya. However, the Dekkera yeasts, which were separated from S. cerevisiae approximately 200 Mya, did not undergo whole genome duplication (WGD but still occupy a niche similar to S. cerevisiae. Upon analysis of two Dekkera yeasts and five closely related non-WGD yeasts, we found that a massive loss of cis-regulatory elements occurred in an ancestor of the Dekkera yeasts, which led to improved mitochondrial functions similar to the S. cerevisiae yeasts. The evolutionary analysis indicated that genes involved in the transcription and translation process exhibited faster evolution in the Dekkera yeasts. We detected 90 positively selected genes, suggesting that the Dekkera yeasts evolved an efficient translation system to facilitate adaptive evolution. Moreover, we identified that 12 vacuolar H+-ATPase (V-ATPase function genes that were under positive selection, which assists in developing tolerance to high alcohol and high sugar stress. We also revealed that the enzyme PGK1 is responsible for the increased rate of glycolysis in the Dekkera yeasts. These results provide important insights to understand the independent adaptive evolution of the Dekkera yeasts and provide tools for genetic modification promoting industrial usage.

  5. Transfer of genetic material between pathogenic and food-borne yeasts

    DEFF Research Database (Denmark)

    Mentel, M.; Spirek, M.; Jorck-Ramberg, D.

    2006-01-01

    Many pathogenic yeast species are asexual and therefore not involved in intra- or interspecies mating. However, high-frequency transfer of plasmid DNA was observed when pathogenic and food-borne yeasts were grown together. This property could play a crucial role in the spread of virulence and drug...... resistance factors among yeasts....

  6. Precursors of ribosomal RNA in yeast nucleus : Biosynthesis and relation to cytoplasmic ribosomal RNA

    NARCIS (Netherlands)

    Sillevis Smitt, W.W.; Vlak, J.M.; Schiphof, R.; Rozijn, Th.H.

    In vivo methylated precursors of ribosomal RNA in yeast have been characterized on acrylamide gels. The initial ribosomal precursor in the yeast nucleus is a 37S RNA component, which is processed to a nuclear 28S RNA. Both the 37S and the 28S RNA components are important constituents of the yeast

  7. Interactions between Drosophila and its natural yeast symbionts—Is Saccharomyces cerevisiae a good model for studying the fly-yeast relationship?

    Directory of Open Access Journals (Sweden)

    Don Hoang

    2015-08-01

    Full Text Available Yeasts play an important role in the biology of the fruit fly, Drosophila melanogaster. In addition to being a valuable source of nutrition, yeasts affect D. melanogaster behavior and interact with the host immune system. Most experiments investigating the role of yeasts in D. melanogaster biology use the baker’s yeast, Saccharomyces cerevisiae. However, S. cerevisiae is rarely found with natural populations of D. melanogaster or other Drosophila species. Moreover, the strain of S. cerevisiae used most often in D. melanogaster experiments is a commercially and industrially important strain that, to the best of our knowledge, was not isolated from flies. Since disrupting natural host–microbe interactions can have profound effects on host biology, the results from D. melanogaster–S. cerevisiae laboratory experiments may not be fully representative of host–microbe interactions in nature. In this study, we explore the D. melanogaster-yeast relationship using five different strains of yeast that were isolated from wild Drosophila populations. Ingested live yeasts have variable persistence in the D. melanogaster gastrointestinal tract. For example, Hanseniaspora occidentalis persists relative to S. cerevisiae, while Brettanomyces naardenensis is removed. Despite these differences in persistence relative to S. cerevisiae, we find that all yeasts decrease in total abundance over time. Reactive oxygen species (ROS are an important component of the D. melanogaster anti-microbial response and can inhibit S. cerevisiae growth in the intestine. To determine if sensitivity to ROS explains the differences in yeast persistence, we measured yeast growth in the presence and absence of hydrogen peroxide. We find that B. naardenesis is completely inhibited by hydrogen peroxide, while H. occidentalis is not, which is consistent with yeast sensitivity to ROS affecting persistence within the D. melanogaster gastrointestinal tract. We also compared the feeding

  8. Evaluation of sugar yeast consumption by measuring electrical medium resistance

    Directory of Open Access Journals (Sweden)

    Martin Lucas Zamora

    2013-12-01

    Full Text Available The real-time monitoring of alcoholic fermentation (sugar consumption is very important in industrial processes. Several techniques (i.e., using a biosensor have been proposed to realize this goal. In this work, we propose a new method to follow sugar yeast consumption. This novel method is based on the changes in the medium resistance (Rm that are induced by the CO2 bubbles produced during a fermentative process. We applied a 50-mV and 700-Hz signal to 75 ml of a yeast suspension in a tripolar cell. A gold electrode was used as the working electrode, whereas an Ag/AgCl electrode and a stainless-steel electrode served as the reference and counter electrodes, respectively. We then added glucose to the yeast suspension and obtained a 700% increase in the Rm after 8 minutes. The addition of sucrose instead of glucose as the carbon source resulted in a 1200% increase in the Rm. To confirm that these changes are the result of CO2 bubbles in the fermentation medium, we designed a tetrapolar cell in which CO2 gas was insufflated at the bottom of the cell and concluded that the changes were due to CO2 bubbles produced during the fermentation. Consequently, this new method is a low-cost and rapid technology to follow the sugar consumption in yeast.

  9. Sorption of volatile phenols by yeast cell walls

    Directory of Open Access Journals (Sweden)

    Nerea Jiménez-Moreno

    2009-01-01

    Full Text Available Nerea Jiménez-Moreno, Carmen Ancín-AzpilicuetaDepartment of Applied Chemistry, Universidad Pública de Navarra, Pamplona, SpainAbstract: Yeast walls can retain different wine compounds and so its use is interesting in order to eliminate harmful substances from the must which affect alcoholic fermentation (medium chain fatty acids or which affect wine quality in a negative way (ethyl phenols, ochratoxin A. The aim of this study was to examine the capacity of commercial yeast cell walls in eliminating volatile phenols (4-ethylphenol and 4-ethylguaiacol from a synthetic wine that contained 1 mg/L of each one of these compounds. The binding of these compounds to the wall was quite fast which would seem to indicate that the yeast wall-volatile compound union is produced in the outer surface layers of this enological additive. The cell walls used reduced the concentration of 4-ethylphenol and 4-ethylguaiacol, although it would seem that on modifying the matrix of the wine the number of free binding sites on the walls is also modified.Keywords: volatile phenols, yeast cell walls, wine, sorption

  10. Why, when, and how did yeast evolve alcoholic fermentation?

    Science.gov (United States)

    Dashko, Sofia; Zhou, Nerve; Compagno, Concetta; Piškur, Jure

    2014-09-01

    The origin of modern fruits brought to microbial communities an abundant source of rich food based on simple sugars. Yeasts, especially Saccharomyces cerevisiae, usually become the predominant group in these niches. One of the most prominent and unique features and likely a winning trait of these yeasts is their ability to rapidly convert sugars to ethanol at both anaerobic and aerobic conditions. Why, when, and how did yeasts remodel their carbon metabolism to be able to accumulate ethanol under aerobic conditions and at the expense of decreasing biomass production? We hereby review the recent data on the carbon metabolism in Saccharomycetaceae species and attempt to reconstruct the ancient environment, which could promote the evolution of alcoholic fermentation. We speculate that the first step toward the so-called fermentative lifestyle was the exploration of anaerobic niches resulting in an increased metabolic capacity to degrade sugar to ethanol. The strengthened glycolytic flow had in parallel a beneficial effect on the microbial competition outcome and later evolved as a "new" tool promoting the yeast competition ability under aerobic conditions. The basic aerobic alcoholic fermentation ability was subsequently "upgraded" in several lineages by evolving additional regulatory steps, such as glucose repression in the S. cerevisiae clade, to achieve a more precise metabolic control.

  11. New yeast strains for alcoholic fermentation at higher sugar concentration

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, M.C.; Ernandes, J.R.; Laluce, C. (Universidade Estadual Paulista, Sao Paulo (BR). Inst. de Quimica)

    1991-03-01

    New yeast strains for alcoholic fermentation were isolated from samples collected from Brazilian alcohol factories at the end of the sugar cane crop season. They were selected for their capacity for fermenting sugar cane syrup as well as high sucrose concentrations in synthetic medium with a conversion efficiency of 89.92%. The strains were identified as Saccharomyces cerevisiae. (author).

  12. Generic sorting of raft lipids into secretory vesicles in yeast

    DEFF Research Database (Denmark)

    Surma, Michal A; Klose, Christian; Klemm, Robin W;

    2011-01-01

    a complete lipid overview of the yeast late secretory pathway. We could show that vesicles captured with different baits carry the same cargo and have almost identical lipid compositions; being highly enriched in ergosterol and sphingolipids. This finding indicates that lipid raft sorting is a generic...... feature of vesicles carrying PM cargo and suggests a common lipid-based mechanism for their formation....

  13. Yeast strains designed for 2. generation bioethanol production. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roennow, B.

    2013-04-15

    The aim of the project was to develop a suitable fermentation organism for 2G bioethanol production that would efficiently ferment all of the sugars in lignocellulosic biomass into ethanol at a commercially viable rate (comparable to yeast based 1G ethanol production). More specifically, a yeast strain would be developed with the ability to ferment also the pentoses in lignocellulosic biomass and thereby increase the ethanol yield of the process by 30-45% with a profound positive effect on the total process economy. The project has succeeded in developing a new industrial yeast strain V1. The yeast strain can transform the difficult C5 sugars to ethanol from waste products such as straw and the like from the agricultural sector. The classic issues relating to industrial uses such as inhibitor and ethanol tolerance and high ethanol production is resolved satisfactorily. The potential of the use of the new strain for 2nd generation bioethanol production is that the ethanol yields increase by 30-45%. With the increased ethanol yield follows a marked improvement in the overall process economics. (LN)

  14. Identification of Telomerase Components and Telomerase Regulating Factors in Yeast

    Science.gov (United States)

    1998-07-01

    required for telomere function. To further explore the mechanism of telomere replication, I identified CDCl3 and EST2 interacting proteins via yeast two...hybrid screens. Characterization of the EST2 interacting proteins may reveal additional telomerase components or regulators. STNl, a high-copy

  15. A theoretical analysis of NADPH production and consumption in yeasts

    NARCIS (Netherlands)

    Bruinenberg, P.M.; Van Dijken, J.P.; Scheffers, W.A.

    1983-01-01

    Theoretical calculations of the NADPH requirement for yeast biomass formation reveal that this parameter is strongly dependent on the carbon and nitrogen source. The data obtained have been used to estimate the carbon flow over the NADPH-producing pathways in these organisms, namely the hexose monop

  16. Engineering industrial yeast for renewable advanced biofuels applications

    Science.gov (United States)

    The industrial yeast Saccharomyces cerevisiae is a candidate for the next-generation biocatalyst development due to its unique genomic background and robust performance in fermentation-based production. In order to meet challenges of renewable and sustainable advanced biofuels conversion including ...

  17. [Isolation, screening and identification of yeast for aquaculture water purification].

    Science.gov (United States)

    Xie, Fengxing; Zhang, Fengfeng; Zhou, Ke; Zhao, Yujie; Sun, Haibo; Wang, Yun

    2015-05-04

    In order to get excellent yeast strains for aquiculture water purification, we isolated, screened and identified yeasts from the aquacultural environment and intestinal tract of shrimp. The potential water purification ability of yeasts, isolated from the activated sludge of aquacultural environment and intestinal tract of white shrimp and mantis shrimp under normal and low temperature, was evaluated in the simulated wastewater. Morphological physio-biochemical characteristics, 5.8S rDNA ITS gene sequence analysis were used to identify the strains. Thirty-seven yeast strains were isolated from 3 samples, among them 16 strains were isolated under normal temperature (25 °C) while 21 strains were isolated under low temperature (15° C). Water purification test suggested 5 strains isolated under 25 °C and 6 strains isolated under 15 °C had higher removal ability of nitrite and ammonia from water. After 48 hours treatment with DN9 and CN6, 10.64 mg/L nitrite in the water was completely removed. After 96 hours treatment, CODcr degradation rates of the 2 strains were 52% and 67%, respectively. According to morphological, physio-biochemical characteristics and 5.8S rDNA ITS gene sequence analysis, the strain DN9 was identified as Rhodotorula mucilaginosa and CN6 as Rhodosporidium paludigenum. Strains DN9 and CN6 would be promising for water purification in aquiculture.

  18. Genetic Instability of Heterozygous, Hybrid, Natural Wine Yeasts

    Science.gov (United States)

    Ramírez, Manuel; Vinagre, Antonia; Ambrona, Jesús; Molina, Felipe; Maqueda, Matilde; Rebollo, JoséE.

    2004-01-01

    We describe a genetic instability found in natural wine yeasts but not in the common laboratory strains of Saccharomyces cerevisiae. Spontaneous cyh2R/cyh2R mutants resistant to high levels of cycloheximide can be directly isolated from cyh2S/cyh2S wine yeasts. Heterozygous cyh2R/cyh2S hybrid clones vary in genetic instability as measured by loss of heterozygosity at cyh2. There were two main classes of hybrids. The lawn hybrids have high genetic instability and generally become cyh2R/cyh2R homozygotes and lose the killer phenotype under nonselective conditions. The papilla hybrids have a much lower rate of loss of heterozygosity and maintain the killer phenotype. The genetic instability in lawn hybrids is 3 to 5 orders of magnitude greater than the highest loss-of-heterozygosity rates previously reported. Molecular mechanisms such as DNA repair by break-induced replication might account for the asymmetrical loss of heterozygosity. This loss-of-heterozygosity phenomenon could be economically important if it causes sudden phenotype changes in industrial or pathogenic yeasts and of more basic importance to the degree that it influences the evolution of naturally occurring yeast populations. PMID:15294803

  19. Highly-efficient electrotransformation of the yeast Hansenula polymorpha

    NARCIS (Netherlands)

    Faber, Klaas Nico; Haima, Peter; Harder, Wim; Veenhuis, Marten; AB, Geert

    1994-01-01

    A highly-efficient method for transformation of the methylotrophic yeast Hansenula polymorpha has been developed. Routinely, transformation frequencies of up to 1.7 × 10^6/µg plasmid DNA were obtained by applying an electric pulse of the exponential decay type of 7.5 kV/cm to a highly-concentrated c

  20. Isolation and characterization of bacteria and yeasts from contaminated soil

    Directory of Open Access Journals (Sweden)

    Karličić Vera M.

    2016-01-01

    Full Text Available Plant growth promoting (PGP bacteria and yeasts play an important role in bioremediation processes. Thirty bacterial and ten yeast isolates were obtained from PAH and PCB contaminated soil with an aim of determining the presence of PGP mechanisms (production of ammonia, indoleacetic acid, siderophores and solubilization of inorganic phosphate. As a result, three bacterial (Serratia liquefaciens, Micrococcus sp. and Serratia sp. and two yeast isolates (Candida utilis and Candida tropicalis were recognized as PGP strains. Among them, Serratia sp. showed the highest indole production (25.5 μg/ml. Analyses of metal tolerance (Cu+2, Cr+6 and Ni+2 revealed that Serratia liquefaciens, Micrococcus sp., Serratia sp. and Candida tropicalis were capable to tolerate significant concentration of metals. As a result of this study several bacterial and yeast strains were attributed as potential plant growth promoters which can be applied in future remediation activities and environmental quality improvements. [Projekat ministarstva nauke Republike Srbije, br. TR 31080 i FP-7 project AREA (316004

  1. Regulation of homologous recombination at telomeres in budding yeast

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine; Lisby, Michael

    2010-01-01

    Homologous recombination is suppressed at normal length telomere sequences. In contrast, telomere recombination is allowed when telomeres erode in the absence of telomerase activity or as a consequence of nucleolytic degradation or incomplete replication. Here, we review the mechanisms...... that contribute to regulating mitotic homologous recombination at telomeres and the role of these mechanisms in signalling short telomeres in the budding yeast Saccharomyces cerevisiae....

  2. Analysis of the hybrid genomes of brewing yeasts

    NARCIS (Netherlands)

    Bolat, I.

    2016-01-01

    One of the best guarded secrets of brewers is represented by the brewing yeast employed in beer fermentation, due to its profound impact upon the specific flavour profile of the final product. The current research tackles the genome diversity of lager brewing strains as well as their impact on

  3. Partial purification and properties of thiaminokinase from yeast

    NARCIS (Netherlands)

    Steyn-Parvé, Elizabeth P.

    1952-01-01

    Thiaminokinase, the enzyme catalyzing the synthesis of thiaminepyrophosphate from thiamine and adenosinetriphosphate, has been extracted from fresh bakers' yeast by plasmolysis by freezing at -70°C and thawing, followed by maceration at 37° in 0.5 M KCl. The enzyme has been partially purified by f

  4. Novel baker's yeast catalysed hydride reduction of an epoxide moiety

    CSIR Research Space (South Africa)

    Horak, RM

    1995-02-27

    Full Text Available -4039(95)00043-7 Tetrahedron Letters, Vol. 36, No. 9, pp. 1541-1544, 1995 Elsevier Science Ltd Printed in Great Britain 0040-4039/95 $9.50+0.00 A Novel Baker's Yeast Catalysed Hydride Reduction of an Epoxide Moiety R. Marthinus Horak, Robin A...

  5. Reflections on the aerobic fermentation stoichiometry of crabtree positive yeasts

    DEFF Research Database (Denmark)

    Villadsen, John; Jørgensen, Sten Bay

    2014-01-01

    In this communication a stoichiometric steady state model for Crabtree positive yeasts is proposed. The model is sufficiently simple to be corroborated by experimental data on the key metabolic events around Dcrit. The key feature of the model is that the bottleneck aperture for biomass productio...

  6. Long-chain alkane production by the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

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

    2015-06-01

    In the past decade industrial-scale production of renewable transportation biofuels has been developed as an alternative to fossil fuels, with ethanol as the most prominent biofuel and yeast as the production organism of choice. However, ethanol is a less efficient substitute fuel for heavy-duty and maritime transportation as well as aviation due to its low energy density. Therefore, new types of biofuels, such as alkanes, are being developed that can be used as drop-in fuels and can substitute gasoline, diesel, and kerosene. Here, we describe for the first time the heterologous biosynthesis of long-chain alkanes by the yeast Saccharomyces cerevisiae. We show that elimination of the hexadecenal dehydrogenase Hfd1 and expression of a redox system are essential for alkane biosynthesis in yeast. Deletion of HFD1 together with expression of an alkane biosynthesis pathway resulted in the production of the alkanes tridecane, pentadecane, and heptadecane. Our study provides a proof of principle for producing long-chain alkanes in the industrial workhorse S. cerevisiae, which was so far limited to bacteria. We anticipate that these findings will be a key factor for further yeast engineering to enable industrial production of alkane based drop-in biofuels, which can allow the biofuel industry to diversify beyond bioethanol.

  7. Yeast Protein–Protein Interaction Assays and Screens

    NARCIS (Netherlands)

    Folter, de S.; Immink, G.H.

    2011-01-01

    Most transcription factors fulfill their role in protein complexes. As a consequence, information about their interaction capacity sheds light on a protein’s function and the molecular mechanism underlying this activity. The yeast two-hybrid GAL4 (Y2H) assay is a powerful method to unravel and ident

  8. Monitoring of yeast cell concentration using a micromachnined impedance sensor

    NARCIS (Netherlands)

    Krommenhoek, E.E.; Gardeniers, Johannes G.E.; Bomer, Johan G.; van den Berg, Albert; Li, X.; Li, X.; Ottens, M.; van der Wielen, L.A.M.; van Dedem, G.W.K.; van Leeuwen, M.; van Gulik, W.M.; Heijnen, J.J.

    2006-01-01

    This paper describes the design, modeling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in Saccharomyces cerevisiae cell culture show that the characteristic fre

  9. Monitoring of yeast cell concentration using a micromachined impedance sensor

    NARCIS (Netherlands)

    Krommenhoek, E.E.; Gardeniers, Johannes G.E.; Bomer, Johan G.; van den Berg, Albert; Li, X.; Ottens, M.; van der Wielen, L.A.M.; van Dedem, G.W.K.; van Leeuwen, M.; van Gulik, W.M.; Heijnen, J.J.

    2005-01-01

    The paper describes the design, modelling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in a Saccharomyces cerevisiae cell culture show that the permittivity of

  10. Yeast and filamentous fungi as model organisms in microbody research

    NARCIS (Netherlands)

    Klei, Ida J. van der; Veenhuis, Marten

    2006-01-01

    Yeast and filamentous fungi are important model organisms in microbody research. The value of these organisms as models for higher eukaryotes is underscored by the observation that the principles of various aspects of microbody biology are strongly conserved from lower to higher eukaryotes. This has

  11. HIGHLY-EFFICIENT ELECTROTRANSFORMATION OF THE YEAST HANSENULA-PALYMORPHA

    NARCIS (Netherlands)

    Faber, Klaas Nico; HAIMA, P.; Harder, W; Veenhuis, M.; AB, G.

    1994-01-01

    A highly-efficient method for transformation of the methylotrophic yeast Hansenula polymorpha has been developed. Routinely, transformation frequencies of up to 1.7 x 10(6)/mu g plasmid DNA were obtained by applying an electric pulse of the exponential decay type of 7.5 kV/cm to a highly-concentrate

  12. Recognition specificity of individual EH domains of mammals and yeast

    DEFF Research Database (Denmark)

    Paoluzi, S; Castagnoli, L; Lauro, I

    1998-01-01

    by characterizing the peptide-binding preference of 11 different EH domains from mammal and yeast proteins. Ten of the eleven EH domains could bind at least some peptides containing an Asn-Pro-Phe (NPF) motif. By contrast, the first EH domain of End3p preferentially binds peptides containing an His-Thr/Ser-Phe (HT...

  13. Lipids from yeasts and fungi: Tomorrow's source of Biodiesel?

    NARCIS (Netherlands)

    Meeuwse, P.; Sanders, J.P.M.; Tramper, J.; Rinzema, A.

    2013-01-01

    In the search for new transport fuels from renewable resources, biodiesel from microbial lipids comes into view. We have evaluated the lipid yield and energy use of a process for production of biodiesel from agricultural waste using lipid-accumulating yeast and fungi. We included different

  14. Prevalence of yeasts in English full blood mares.

    Science.gov (United States)

    Różański, Paweł; Slaska, Brygida; Różańska, Dorota

    2013-04-01

    The aim of the study was a quantitative and qualitative analysis of microflora, presentation of current data about prevalence of the microflora on the skin and mucous membranes, and determination of its possible effect on reproduction of English full blood horses bred in Poland. The material for analyses was sampled from the skin and mucous membranes (385 samples) of 55 English full blood mares. Taking into account reproduction traits, the mares were classified into three groups. Six yeast-like species, including five species from the genus Candida (C. albicans, C. guiliermondii, C. lusitaniae, C. sp., and C. tropicalis) and Trichomonascus ciferrii, were detected on the skin and mucous membranes in the English full blood mares. Growth of yeasts was observed in more than half of the samples taken from mares that had foaled and approximately 46 % of non-conceiving and barren mares. The high prevalence of various yeast strains in the mouth, nostrils, and collateral groove may suggest widespread occurrence of the microflora in the breeding environment. The results obtained indicate that the yeasts isolated in this study may be components of the normal microflora of the skin and mucous membranes in horses. The analysis results do not indicate unambiguously that the isolated microflora affects reproduction in mares, although this cannot be excluded.

  15. Affected chromosome homeostasis and genomic instability of clonal yeast cultures.

    Science.gov (United States)

    Adamczyk, Jagoda; Deregowska, Anna; Panek, Anita; Golec, Ewelina; Lewinska, Anna; Wnuk, Maciej

    2016-05-01

    Yeast cells originating from one single colony are considered genotypically and phenotypically identical. However, taking into account the cellular heterogeneity, it seems also important to monitor cell-to-cell variations within a clone population. In the present study, a comprehensive yeast karyotype screening was conducted using single chromosome comet assay. Chromosome-dependent and mutation-dependent changes in DNA (DNA with breaks or with abnormal replication intermediates) were studied using both single-gene deletion haploid mutants (bub1, bub2, mad1, tel1, rad1 and tor1) and diploid cells lacking one active gene of interest, namely BUB1/bub1, BUB2/bub2, MAD1/mad1, TEL1/tel1, RAD1/rad1 and TOR1/tor1 involved in the control of cell cycle progression, DNA repair and the regulation of longevity. Increased chromosome fragility and replication stress-mediated chromosome abnormalities were correlated with elevated incidence of genomic instability, namely aneuploid events-disomies, monosomies and to a lesser extent trisomies as judged by in situ comparative genomic hybridization (CGH). The tor1 longevity mutant with relatively balanced chromosome homeostasis was found the most genomically stable among analyzed mutants. During clonal yeast culture, spontaneously formed abnormal chromosome structures may stimulate changes in the ploidy state and, in turn, promote genomic heterogeneity. These alterations may be more accented in selected mutated genetic backgrounds, namely in yeast cells deficient in proper cell cycle regulation and DNA repair.

  16. Crystal structure of the 80S yeast ribosome.

    Science.gov (United States)

    Jenner, Lasse; Melnikov, Sergey; Garreau de Loubresse, Nicolas; Ben-Shem, Adam; Iskakova, Madina; Urzhumtsev, Alexandre; Meskauskas, Arturas; Dinman, Jonathan; Yusupova, Gulnara; Yusupov, Marat

    2012-12-01

    The first X-ray structure of the eukaryotic ribosome at 3.0Å resolution was determined using ribosomes isolated and crystallized from the yeast Saccharomyces cerevisiae (Ben-Shem A, Garreau de Loubresse N, Melnikov S, Jenner L, Yusupova G, Yusupov M: The structure of the eukaryotic ribosome at 3.0 A resolution. Science 2011, 334:1524-1529). This accomplishment was possible due to progress in yeast ribosome biochemistry as well as recent advances in crystallographic methods developed for structure determination of prokaryotic ribosomes isolated from Thermus thermophilus and Escherichia coli. In this review we will focus on the development of isolation procedures that allowed structure determination (both cryo-EM and X-ray crystallography) to be successful for the yeast S. cerevisiae. Additionally we will introduce a new nomenclature that facilitates comparison of ribosomes from different species and kingdoms of life. Finally we will discuss the impact of the yeast 80S ribosome crystal structure on perspectives for future investigations.

  17. Growth of marine yeast on different strength of stress solutes

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, R.

    excellent growth at 4% and good growth at 65% NaCl. Species of red yeast Rhodotorula lost its pigment production at 6%, except R. rubra which grew up to 16% NaCl with faint pigmentation. Six species of genera Debaryomyces, Saccharomyces and Rhodotorula were...

  18. Effects of yeast, fermentation time, and preservation methods on tarhana.

    Science.gov (United States)

    Gurbuz, Ozan; Gocmen, Duygu; Ozmen, Nese; Dagdelen, Fatih

    2010-01-01

    The physicochemical properties of tarhana soup produced with different dough treatments, fermentation times, and preservation methods were examined. Tarhana doughs were prepared with yogurt (control) or baker's yeast (Saccharomyces cerevisiae) and fermented for 3 days. Samples were taken at 24, 48, and 72 hr. Samples were then preserved via one of four methods: sun dried, dried in the shade, vacumn dried, and frozen. Frozen samples produced lower organic acid levels after 72 hr of fermentation in both control (0.68 g/100 g) and yeast (0.61 g/100 g) applications than samples that were dried (0.94 g/100 g control samples; 0.81 g/100 g samples with yeast). Increasing fermentation time resulted in a significant effect on the formation of organic acid in the tarhana (p .01). However, sensory scores for tarhana prepared from the samples dried in a sheltered area showed a reduction in color desireablilty as the fermentation time increased. The soup prepared from frozen tarhana (72 hr fermentation, with yeast) had the highest scores with respect to color, mouth feel, flavor, and overall acceptability. Vacuum-dried samples' scores in these areas were also high in comparison to the two other drying methods.

  19. Partial purification and properties of thiaminokinase from yeast

    NARCIS (Netherlands)

    Steyn-Parvé, Elizabeth P.

    1952-01-01

    Thiaminokinase, the enzyme catalyzing the synthesis of thiaminepyrophosphate from thiamine and adenosinetriphosphate, has been extracted from fresh bakers' yeast by plasmolysis by freezing at -70°C and thawing, followed by maceration at 37° in 0.5 M KCl. The enzyme has been partially purified by f

  20. 21 CFR 573.750 - Pichia pastoris dried yeast.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Pichia pastoris dried yeast. 573.750 Section 573.750 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.750 Pichia...

  1. The Treasure of the Humble: Lessons from Baker's Yeast

    Science.gov (United States)

    Sitaraman, Ramakrishnan

    2011-01-01

    The study of model organisms is a powerful and proven experimental strategy for understanding biological processes. This paper describes an attempt to utilize advances in yeast molecular biology to enhance student understanding by presenting a more comprehensive view of several interconnected molecular processes in the overall functioning of an…

  2. 21 CFR 172.590 - Yeast-malt sprout extract.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Yeast-malt sprout extract. 172.590 Section 172.590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Flavoring Agents and Related Substance...

  3. 21 CFR 184.1983 - Bakers yeast extract.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Bakers yeast extract. 184.1983 Section 184.1983 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 18...

  4. Efficient transformation of the astaxanthin-producing yeast Phaffia rhodozyma.

    NARCIS (Netherlands)

    Wery, J.; Verdoes, J.C.; Ooyen, van A.J.J.

    1998-01-01

    An efficient transformation system for the astaxanthin-producing yeast Phaffia rhodozyma was developed based on electroporation that routinely yields approximately 1000 transformants per g of plasmid DNA. The high transformation efficiency depends on vector integration in the ribosomal DNA (rDNA) an

  5. Conjugation in the Yeast Saccharomycopsis capsularis Schiönning

    NARCIS (Netherlands)

    Kreger-van Rij, N.J.W.; Veenhuis, M.

    1975-01-01

    Cells of the yeast Saccharomycopsis capsularis fused in pairs after dissolving of part of the cross wall between them near the lateral wall. After nuclear migrations through the opening, the cross wall was closed again and the cells at both sides became asci. The wall of the ascospores developed fro

  6. Evidence for functional heterogeneity among microbodies in yeasts

    NARCIS (Netherlands)

    Veenhuis, Marten; Sulter, Grietje; Klei, Ida van der; Harder, Wim

    1989-01-01

    We have studied the biogenesis and enzymic composition of microbodies in different yeasts during adaptation of cells to a new growth environment. After a shift of cells of Candida boidinii and Hansenula polymorpha from glucose to methanol/methylamine-containing media, newly synthesized alcohol oxida

  7. Peroxisomal catalase deficiency modulates yeast lifespan depending on growth conditions

    NARCIS (Netherlands)

    Kawalek, Adam; Lefevre, Sophie D.; Veenhuis, Marten; van der Klei, Ida J.

    2013-01-01

    We studied the role of peroxisomal catalase in chronological aging of the yeast Hansenula polymorpha in relation to various growth substrates. Catalase-deficient (cat) cells showed a similar chronological life span (CLS) relative to the wild-type control upon growth on carbon and nitrogen sources th

  8. Air-drying kinetics affect yeast membrane organization and survival.

    Science.gov (United States)

    Lemetais, Guillaume; Dupont, Sébastien; Beney, Laurent; Gervais, Patrick

    2012-10-01

    The plasma membrane (PM) is a key structure for the survival of cells during dehydration. In this study, we focused on the concomitant changes in survival and in the lateral organization of the PM in yeast strains during desiccation, a natural or technological environmental perturbation that involves transition from a liquid to a solid medium. To evaluate the role of the PM in survival during air-drying, a wild-type yeast strain and an osmotically fragile mutant (erg6Δ) were used. The lateral organization of the PM (microdomain distribution) was observed using a fluorescent marker related to a specific green fluorescent protein-labeled membrane protein (Sur7-GFP) after progressive or rapid desiccation. We also evaluated yeast behavior during a model dehydration experiment performed in liquid medium (osmotic stress). For both strains, we observed similar behavior after osmotic and desiccation stresses. In particular, the same lethal magnitude of dehydration and the same lethal kinetic effect were found for both dehydration methods. Thus, yeast survival after progressive air-drying was related to PM reorganization, suggesting the positive contribution of passive lateral rearrangements of the membrane components. This study also showed that the use of glycerol solutions is an efficient means to simulate air-drying desiccation.

  9. Membrane trafficking in the yeast Saccharomyces cerevisiae model.

    Science.gov (United States)

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

    2015-01-09

    The yeast Saccharomyces cerevisiae is one of the best characterized eukaryotic models. The secretory pathway was the first trafficking pathway clearly understood mainly thanks to the work done in the laboratory of Randy Schekman in the 1980s. They have isolated yeast sec mutants unable to secrete an extracellular enzyme and these SEC genes were identified as encoding key effectors of the secretory machinery. For this work, the 2013 Nobel Prize in Physiology and Medicine has been awarded to Randy Schekman; the prize is shared with James Rothman and Thomas Südhof. Here, we present the different trafficking pathways of yeast S. cerevisiae. At the Golgi apparatus newly synthesized proteins are sorted between those transported to the plasma membrane (PM), or the external medium, via the exocytosis or secretory pathway (SEC), and those targeted to the vacuole either through endosomes (vacuolar protein sorting or VPS pathway) or directly (alkaline phosphatase or ALP pathway). Plasma membrane proteins can be internalized by endocytosis (END) and transported to endosomes where they are sorted between those targeted for vacuolar degradation and those redirected to the Golgi (recycling or RCY pathway). Studies in yeast S. cerevisiae allowed the identification of most of the known effectors, protein complexes, and trafficking pathways in eukaryotic cells, and most of them are conserved among eukaryotes.

  10. Recent advances in yeast molecular biology: recombinant DNA. [Lead abstract

    Energy Technology Data Exchange (ETDEWEB)

    1982-09-01

    Separate abstracts were prepared for the 25 papers presented at a workshop focusing on chromosomal structure, gene regulation, recombination, DNA repair, and cell type control, that have been obtained by experimental approaches incorporating the new technologies of yeast DNA transformation, molecular cloning, and DNA sequence analysis. (KRM)

  11. Developing a yeast-based assay protocol to monitor total ...

    African Journals Online (AJOL)

    2005-06-21

    Jun 21, 2005 ... in a sample to which the yeast was exposed over a 20 h incu- bation period. ... umes and a 20 h incubation time. ... (Forma Scientific, USA) until used. The use of ..... al., 2002; Andersen et al., 2003; Svenson et al., 2003; Ser-.

  12. Morphological Instabilities in a Growing Yeast Colony: Experiment and Theory

    DEFF Research Database (Denmark)

    Sams, Thomas; Sneppen, Kim; Jensen, Mogens;

    1997-01-01

    We study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended over a solution of nutrients. As the thickness of the agarose film is varied, the morphology of the ...

  13. Effect of chromosome tethering on nuclear organization in yeast.

    Directory of Open Access Journals (Sweden)

    Barış Avşaroğlu

    Full Text Available Interphase chromosomes in Saccharomyces cerevisiae are tethered to the nuclear envelope at their telomeres and to the spindle pole body (SPB at their centromeres. Using a polymer model of yeast chromosomes that includes these interactions, we show theoretically that telomere attachment to the nuclear envelope is a major determinant of gene positioning within the nucleus only for genes within 10 kb of the telomeres. We test this prediction by measuring the distance between the SPB and the silent mating locus (HML on chromosome III in wild-type and mutant yeast strains that contain altered chromosome-tethering interactions. In wild-type yeast cells we find that disruption of the telomere tether does not dramatically change the position of HML with respect to the SPB, in agreement with theoretical predictions. Alternatively, using a mutant strain with a synthetic tether that localizes an HML-proximal site to the nuclear envelope, we find a significant change in the SPB-HML distance, again as predicted by theory. Our study quantifies the importance of tethering at telomeres on the organization of interphase chromosomes in yeast, which has been shown to play a significant role in determining chromosome function such as gene expression and recombination.

  14. Bakers yeast-mediated transformations of alpha-keto epoxides

    CSIR Research Space (South Africa)

    Meth-Cohn, O

    1994-06-07

    Full Text Available Alpha beta-Epoxy ketones on treatment with baker's yeast yield different types of products depending on their substitution. Small groups such as H or Me attached at the epoxy end protect that end from attack. Thus, 1-acyl epoxides with H, methyl...

  15. Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model

    Directory of Open Access Journals (Sweden)

    Serge Feyder

    2015-01-01

    Full Text Available The yeast Saccharomyces cerevisiae is one of the best characterized eukaryotic models. The secretory pathway was the first trafficking pathway clearly understood mainly thanks to the work done in the laboratory of Randy Schekman in the 1980s. They have isolated yeast sec mutants unable to secrete an extracellular enzyme and these SEC genes were identified as encoding key effectors of the secretory machinery. For this work, the 2013 Nobel Prize in Physiology and Medicine has been awarded to Randy Schekman; the prize is shared with James Rothman and Thomas Südhof. Here, we present the different trafficking pathways of yeast S. cerevisiae. At the Golgi apparatus newly synthesized proteins are sorted between those transported to the plasma membrane (PM, or the external medium, via the exocytosis or secretory pathway (SEC, and those targeted to the vacuole either through endosomes (vacuolar protein sorting or VPS pathway or directly (alkaline phosphatase or ALP pathway. Plasma membrane proteins can be internalized by endocytosis (END and transported to endosomes where they are sorted between those targeted for vacuolar degradation and those redirected to the Golgi (recycling or RCY pathway. Studies in yeast S. cerevisiae allowed the identification of most of the known effectors, protein complexes, and trafficking pathways in eukaryotic cells, and most of them are conserved among eukaryotes.

  16. Analysis of the hybrid genomes of brewing yeasts

    NARCIS (Netherlands)

    Bolat, I.

    2016-01-01

    One of the best guarded secrets of brewers is represented by the brewing yeast employed in beer fermentation, due to its profound impact upon the specific flavour profile of the final product. The current research tackles the genome diversity of lager brewing strains as well as their impact on impor

  17. V-ATPase, ScNhxlp and Yeast Vacuole Fusion

    Institute of Scientific and Technical Information of China (English)

    Quan-Sheng Qiu

    2012-01-01

    Membrane fusion is the last step in trafficking pathways during which membrane vesicles fuse with target organelles to deliver cargos.It is a central cellular reaction that plays important roles in signal transduction,protein sorting and subcellular compartmentation.Recent progress in understanding the roles of ion transporters in vacuole fusion in yeast is summanzed in this article.It is becoming increasingly evident that the vacuolar proton pump V-ATPase and vacuolar Na+/H+ antiporter ScNhxlp are key components of the vacuole fusion machinery in yeast.Yeast ScNhxlp regulates vacuole fusion by controlling the luminal pH.V-ATPases serve a dual role in vacuolar integrity in which they regulate both vacuole fusion and fission reactions in yeast.Fission defects are epistatic to fusion defects.Vacuole fission depends on the proton translocation activity of the V-ATPase; by contrast,the fusion reaction does not need the transport activity but requires the physical presence of the proton pump.Vo,the membrane-integral sector of the V-ATPase,forms trans-complexes between the opposing vacuoles in the terminal phase of vacuole fusion where the Vo trans-complexes build a continuous proteolipid channel at the fusion site to mediate the bilayer fusion.

  18. Reconstitution of the mitochondrial calcium uniporter in yeast.

    Science.gov (United States)

    Kovács-Bogdán, Erika; Sancak, Yasemin; Kamer, Kimberli J; Plovanich, Molly; Jambhekar, Ashwini; Huber, Robert J; Myre, Michael A; Blower, Michael D; Mootha, Vamsi K

    2014-06-17

    The mitochondrial calcium uniporter is a highly selective calcium channel distributed broadly across eukaryotes but absent in the yeast Saccharomyces cerevisiae. The molecular components of the human uniporter holocomplex (uniplex) have been identified recently. The uniplex consists of three membrane-spanning subunits--mitochondrial calcium uniporter (MCU), its paralog MCUb, and essential MCU regulator (EMRE)--and two soluble regulatory components--MICU1 and its paralog MICU2. The minimal components sufficient for in vivo uniporter activity are unknown. Here we consider Dictyostelium discoideum (Dd), a member of the Amoebazoa outgroup of Metazoa and Fungi, and show that it has a highly simplified uniporter machinery. We show that D. discoideum mitochondria exhibit membrane potential-dependent calcium uptake compatible with uniporter activity, and also that expression of DdMCU complements the mitochondrial calcium uptake defect in human cells lacking MCU or EMRE. Moreover, expression of DdMCU in yeast alone is sufficient to reconstitute mitochondrial calcium uniporter activity. Having established yeast as an in vivo reconstitution system, we then reconstituted the human uniporter. We show that coexpression of MCU and EMRE is sufficient for uniporter activity, whereas expression of MCU alone is insufficient. Our work establishes yeast as a powerful in vivo reconstitution system for the uniporter. Using this system, we confirm that MCU is the pore-forming subunit, define the minimal genetic elements sufficient for metazoan and nonmetazoan uniporter activity, and provide valuable insight into the evolution of the uniporter machinery.

  19. Functional analysis of expressed peptides that bind yeast STE proteins.

    Science.gov (United States)

    Caponigro, Giordano; Abedi, Majid; Kamb, Alexander

    2003-08-15

    Peptides are potentially useful for target validation and other reverse genetic applications. For instance, if a specific protein is susceptible to peptide inhibition, it may have a higher probability of being vulnerable to small molecules. We used the yeast two-hybrid technique to identify and study peptide binders for three yeast proteins involved in pheromone response: Ste11p, Ste18p, and Ste50p. A subset of peptide binders was shown to inhibit pheromone response in cells using two different functional assays. In addition, we utilized a variant of the yeast two-hybrid method to examine relative binding affinities based on competitive interactions in yeast. Our results suggest that binding affinity and inhibitory potency of peptides do not correlate perfectly and that peptide-protein interactions can be complex and unpredictable. Taken together these results suggest that while peptides are useful as in vivo inhibitors of protein function, caution must be exercised when choosing peptides for further studies and when inferring affinities from expression phenotypes.

  20. Method for using a yeast alpha-amylase promoter

    Science.gov (United States)

    Gao, Johnway; Skeen, Rodney S.; Hooker, Brian S.; Anderson, Daniel B.

    2003-04-22

    The present invention provides the promoter clone discovery of an alpha-amylase gene of a starch utilizing yeast strain Schwanniomyces castellii. The isolated alpha-amylase promoter is an inducible promoter, which can regulate strong gene expression in starch culture medium.