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Sample records for bakers yeast

  1. 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...

  2. 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... Listing of Specific Substances Affirmed as GRAS § 184.1983 Bakers yeast extract. (a) Bakers yeast extract... a selected strain of yeast, Saccharomyces cerevisiae. It may be concentrated or dried. (b)...

  3. 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...

  4. 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.

  5. 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.

  6. Isolation of a tyrosine-activating enzyme from baker's yeast

    NARCIS (Netherlands)

    Ven, A.M. van de; Koningsberger, V.V.; Overbeek, J.Th.G.

    1958-01-01

    The extracts of ether-CO2-frozen baker's yeast contain enzymes that catalyze the ATP-linked amino acid activation by way of pyrophosphate elimination. From the extract a tyrosine-activating enzyme could be isolated, which, judging from ultracentrifugation and electrophoretic data, was about 70% pure

  7. Baker's Yeast Mediated Reduction of Optically Active Diketone

    Institute of Scientific and Technical Information of China (English)

    ZHENG, Guo-Jun(郑国君); GAO, Xiao-Lei(高晓蕾); CHEN, Jin-Chun(陈锦春); LI, Yu-Lin(李裕林)

    2004-01-01

    Baker's yeast mediated reduction of optically active diketone is described. The two keto groups are efficiently differentiated and the ee value of the recovered material is considerably raised. It affords highly optically active key intermediates efficiently for the synthesis of natural polyhydroxylated agarofuran products.

  8. Construction of a lactose-assimilating strain of baker's yeast.

    Science.gov (United States)

    Adam, A C; Prieto, J A; Rubio-Texeira, M; Polaina, J

    1999-09-30

    A recombinant strain of baker's yeast has been constructed which can assimilate lactose efficiently. This strain has been designed to allow its propagation in whey, the byproduct resulting from cheese-making. The ability to metabolize lactose is conferred by the functional expression of two genes from Kluyveromyces lactis, LAC12 and LAC4, which encode a lactose permease and a beta-galactosidase, respectively. To make the recombinant strain more acceptable for its use in bread-making, the genetic transformation of the host baker's yeast was carried out with linear fragments of DNA of defined sequence, carrying as the only heterologous material the coding regions of the two K. lactis genes. Growth of the new strain on cheese whey affected neither the quality of bread nor the yeast gassing power. The significance of the newly developed strain is two-fold: it affords a cheap alternative to the procedure generally used for the propagation of baker's yeast, and it offers a profitable use for cheese whey.

  9. 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.

  10. Baker's Yeast: improving the D-stereoselectivity in reduction of 3-oxo esters

    DEFF Research Database (Denmark)

    Madsen, Jørgen Øgaard

    1999-01-01

    The stereoselectivity of baker's yeast in the reduction of ethyl 3-oxopentanoate was shifted towards the corresponding (R)-hydroxy ester by sugar, heat treatment and allyl alcohol. The highest enantiomeric excesses obtained with baker's yeast with a good reduction capacity, 92-97%, were achieved...... of the (R)-enantiomer of ethyl 3-hydroxybutanoate was obtained with ordinary baker's yeast. (C) 1999 Elsevier Science Ltd. All rights reserved....

  11. Removal of heavy metal from industrial effluents using Baker's yeast

    Science.gov (United States)

    Ferdous, Anika; Maisha, Nuzhat; Sultana, Nayer; Ahmed, Shoeb

    2016-07-01

    Bioremediation of wastewater containing heavy metals is one of the major challenges in environmental biotechnology. Heavy metals are not degraded and as a result they remain in the ecosystem, and pose serious health hazards as it comes in contact with human due to anthropogenic activities. Biological treatment with various microorganisms has been practiced widely in recent past, however, accessing and maintaining the microorganisms have always been a challenge. Microorganisms like Baker's yeast can be very promising biosorbents as they offer high surface to volume ratio, large availability, rapid kinetics of adsorption and desorption and low cost. The main aim of this study is to evaluate the applicability of the biosorption process using baker's yeast. Here we present an experimental investigation of biosorption of Chromium (Cr) from water using commercial Baker's Yeast. It was envisaged that yeast, dead or alive, would adsorb heavy metals, however, operating parameters could play vital roles in determining the removal efficiency. Parameters, such as incubation time, pH, amount of biosorbent and heavy metal concentration were varied to investigate the impacts of those parameters on removal efficiency. Rate of removal was found to be inversely proportional to the initial Cr (+6) concentrations but the removal rate per unit biomass was a weakly dependent on initial Cr(+6) concentrations. Biosorption process was found to be more efficient at lower pH and it exhibited lower removal with the increase in solution pH. The optimum incubation time was found to be between 6-8 hours and optimum pH for the metal ion solution was 2. The effluents produced in leather industries are the major source of chromium pollution in Bangladesh and this study has presented a very cost effective yet efficient heavy metal removal approach that can be adopted for such kind of wastewater.

  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. Enhanced leavening properties of baker's yeast by reducing sucrase activity in sweet dough.

    Science.gov (United States)

    Zhang, Cui-Ying; Lin, Xue; Feng, Bing; Liu, Xiao-Er; Bai, Xiao-Wen; Xu, Jia; Pi, Li; Xiao, Dong-Guang

    2016-07-01

    Leavening ability in sweet dough is required for the commercial applications of baker's yeast. This property depends on many factors, such as glycolytic activity, sucrase activity, and osmotolerance. This study explored the importance of sucrase level on the leavening ability of baker's yeast in sweet dough. Furthermore, the baker's yeast strains with varying sucrase activities were constructed by deleting SUC2, which encodes sucrase or replacing the SUC2 promoter with the VPS8/TEF1 promoter. The results verify that the sucrase activity negatively affects the leavening ability of baker's yeast strains under high-sucrose conditions. Based on a certain level of osmotolerance, sucrase level plays a significant role in the fermentation performance of baker's yeast, and appropriate sucrase activity is an important determinant for the leavening property of baker's yeast in sweet dough. Therefore, modification on sucrase activity is an effective method for improving the leavening properties of baker's yeast in sweet dough. This finding provides guidance for the breeding of industrial baker's yeast strains for sweet dough leavening. The transformants BS1 with deleted SUC2 genetic background provided decreased sucrase activity (a decrease of 39.3 %) and exhibited enhanced leavening property (an increase of 12.4 %). Such a strain could be useful for industrial applications.

  14. Generation of thiols by biotransformation of cysteine-aldehyde conjugates with baker's yeast.

    Science.gov (United States)

    Huynh-Ba, Tuong; Matthey-Doret, Walter; Fay, Laurent B; Bel Rhlid, Rachid

    2003-06-01

    Baker's yeast was shown to catalyze the transformation of cysteine-furfural conjugate into 2-furfurylthiol. The biotransformation's yield and kinetics were influenced by the reaction parameters such as pH, incubation mode (aerobic and anaerobic), and substrate concentration. 2-Furfurylthiol was obtained in an optimal 37% yield when cysteine-furfural conjugate at a 20 mM concentration was anaerobically incubated with whole cell baker's yeast at pH 8.0 and 30 degrees C. Similarly to 2-furfurylthiol, 5-methyl-2-furfurylthiol (11%), benzylthiol (8%), 2-thiophenemethanethiol (22%), 3-methyl-2-thiophenemethanethiol (3%), and 2-pyrrolemethanethiol (6%) were obtained from the corresponding cysteine-aldehyde conjugates by incubation with baker's yeast. This work indicates the versatile bioconversion capacity of baker's yeast for the generation of thiols from cysteine-aldehyde conjugates. Thanks to its food-grade character, baker's yeast provides a biochemical tool to produce thiols, which can be used as flavorings in foods and beverages.

  15. Optimization of the flux values in multichannel ceramic membrane microfiltration of Baker`s yeast suspension

    Directory of Open Access Journals (Sweden)

    Milović Nemanja R.

    2016-01-01

    Full Text Available The objective of this work was to estimate the effects of the operating parameters on the baker's yeast microfiltration through multichannel ceramic membrane. The selected parameters were transmembrane pressure, suspension feed flow, and initial suspension concentration. In order to investigate the influence and interaction effects of these parameters on the microfiltration operation, two responses have been chosen: average permeate flux and flux decline. The Box-Behnken experimental design and response surface methodology was used for result processing and process optimization. According to the obtained results, the most important parameter influencing permeate flux during microfiltration is the initial suspension concentration. The maximum average flux value was achieved at an initial concentration of 0.1 g/L, pressure around 1.25 bars and a flow rate at 16 L/h. [Projekat Ministarstva nauke Republike Srbije, br. TR 31002

  16. Improved vanillin production in baker's yeast through in silico design

    Directory of Open Access Journals (Sweden)

    Hansen Jørgen

    2010-11-01

    Full Text Available Abstract Background Vanillin is one of the most widely used flavouring agents, originally obtained from cured seed pods of the vanilla orchid Vanilla planifolia. Currently vanillin is mostly produced via chemical synthesis. A de novo synthetic pathway for heterologous vanillin production from glucose has recently been implemented in baker's yeast, Saccharamyces cerevisiae. In this study we aimed at engineering this vanillin cell factory towards improved productivity and thereby at developing an attractive alternative to chemical synthesis. Results Expression of a glycosyltransferase from Arabidopsis thaliana in the vanillin producing S. cerevisiae strain served to decrease product toxicity. An in silico metabolic engineering strategy of this vanillin glucoside producing strain was designed using a set of stoichiometric modelling tools applied to the yeast genome-scale metabolic network. Two targets (PDC1 and GDH1 were selected for experimental verification resulting in four engineered strains. Three of the mutants showed up to 1.5 fold higher vanillin β-D-glucoside yield in batch mode, while continuous culture of the Δpdc1 mutant showed a 2-fold productivity improvement. This mutant presented a 5-fold improvement in free vanillin production compared to the previous work on de novo vanillin biosynthesis in baker's yeast. Conclusion Use of constraints corresponding to different physiological states was found to greatly influence the target predictions given minimization of metabolic adjustment (MOMA as biological objective function. In vivo verification of the targets, selected based on their predicted metabolic adjustment, successfully led to overproducing strains. Overall, we propose and demonstrate a framework for in silico design and target selection for improving microbial cell factories.

  17. 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

  18. Formulation and evaluation of acyclovir microcapsules using bakers yeast

    Institute of Scientific and Technical Information of China (English)

    Krishnan PN; Saraswathi R; Dilip C; Ramarao N

    2010-01-01

    Objective:To formulate and evaluate acyclovir microcapsules using bakers yeast. Methods:Acyclovir, pretreated yeast and deionised water were taken at a volumetric ratio of 1:2:4 respectively. This suspension was agitated in a magnetic stirrer at 25℃, 30℃, 35℃, and 40℃for 4 hours. The suspension was then centrifuged for 10 minutes at 2 000 rpm. The supernatant solution was decanted and the cells were washed 5 times with deionised water. Then the suspended drug entrapped yeast cells were dried in a lyophillizer for 48 hours. The yield was noted. Results:The first four formulations were done with 200 mg of the drug, followed by 400 mg for the next four formulations and 800 mg the last four formulations. SEM showed that the surface of the microcapsules was intact, with no burst characteristics. FTIR showed no interaction between acyclovir and the cell wall. DSC showed that the peak was within the standard values. The mean particle size for all the samples was 8 μm in diameter. The dissolution studies were done for all the twelve samples and showed a Fickian model of diffusion. Conclusions:From the results it is inferred that the samples prepared at 40℃(FY-4, FY-8, FY-12) show better entrapment and release. So these samples are formulated in the form of a suspension and compared with marketed acyclovir suspension using HPLC technique. The formulated suspensions with FY-4, FY-8 and FY-12 shows drug content in accordance with the standards of the pharmacopoeial limits.

  19. Kazachstania gamospora and Wickerhamomyces subpelliculosus: Two alternative baker's yeasts in the modern bakery.

    Science.gov (United States)

    Zhou, Nerve; Schifferdecker, Anna Judith; Gamero, Amparo; Compagno, Concetta; Boekhout, Teun; Piškur, Jure; Knecht, Wolfgang

    2017-03-22

    Saccharomyces cerevisiae, the conventional baker's yeast, remains the most domesticated yeast monopolizing the baking industry. Its rapid consumption of sugars and production of CO2 are the most important attributes required to leaven the dough. New research attempts highlight that these attributes are not unique to S. cerevisiae, but also found in several non-conventional yeast species. A small number of these yeast species with similar properties have been described, but remain poorly studied. They present a vast untapped potential for the use as leavening agents and flavor producers due to their genetic and phylogenetic diversity. We assessed the potential of several non-conventional yeasts as leavening agents and flavor producers in dough-like conditions in the presence of high sugar concentrations and stressful environments mimicking conditions found in flour dough. We tested the capabilities of bread leavening and aroma formation in a microbread platform as well as in a bakery setup. Bread leavened with Kazachstania gamospora and Wickerhamomyces subpelliculosus had better overall results compared to control baker's yeast. In addition, both displayed higher stress tolerance and broader aroma profiles than the control baker's yeast. These attributes are important in bread and other farinaceous products, making K. gamospora and W. subpelliculosus highly applicable as alternative baker's yeasts.

  20. 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.

  1. 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.

  2. Improvement of tolerance to freeze-thaw stress of baker's yeast by cultivation with soy peptides.

    Science.gov (United States)

    Izawa, Shingo; Ikeda, Kayo; Takahashi, Nobuyuki; Inoue, Yoshiharu

    2007-06-01

    The tolerance to freeze-thaw stress of yeast cells is critical for frozen-dough technology in the baking industry. In this study, we examined the effects of soy peptides on the freeze-thaw stress tolerance of yeast cells. We found that the cells cultured with soy peptides acquired improved tolerance to freeze-thaw stress and retained high leavening ability in dough after frozen storage for 7 days. The final quality of bread regarding its volume and texture was also improved by using yeast cells cultured with soy peptides. These findings promote the utilization of soy peptides as ingredients of culture media to improve the quality of baker's yeast.

  3. Effects of SNF1 on Maltose Metabolism and Leavening Ability of Baker's Yeast in Lean Dough.

    Science.gov (United States)

    Zhang, Cui-Ying; Bai, Xiao-Wen; Lin, Xue; Liu, Xiao-Er; Xiao, Dong-Guang

    2015-12-01

    Maltose metabolism of baker's yeast (Saccharomyces cerevisiae) in lean dough is negatively influenced by glucose repression, thereby delaying the dough fermentation. To improve maltose metabolism and leavening ability, it is necessary to alleviate glucose repression. The Snf1 protein kinase is well known to be essential for the response to glucose repression and required for transcription of glucose-repressed genes including the maltose-utilization genes (MAL). In this study, the SNF1 overexpression and deletion industrial baker's yeast strains were constructed and characterized in terms of maltose utilization, growth and fermentation characteristics, mRNA levels of MAL genes (MAL62 encoding the maltase and MAL61 encoding the maltose permease) and maltase and maltose permease activities. Our results suggest that overexpression of SNF1 was effective to glucose derepression for enhancing MAL expression levels and enzymes (maltase and maltose permease) activities. These enhancements could result in an 18% increase in maltose metabolism of industrial baker's yeast in LSMLD medium (the low sugar model liquid dough fermentation medium) containing glucose and maltose and a 15% increase in leavening ability in lean dough. These findings provide a valuable insight of breeding industrial baker's yeast for rapid fermentation.

  4. Baker's yeast catalyzed asymmetric reduction of methyl acetoacetate in glycerol containing systems

    Directory of Open Access Journals (Sweden)

    Adi Wolfson

    2008-09-01

    Full Text Available The asymmetric hydrogenation of methyl acetoacetate was successfully performed with baker's yeast in pure glycerol and mixtures of glycerol and water. Though yeast viability was very low after exposure to glycerol, the enzymatic activity in pure glycerol was preserved for some days. In addition, a mixture of glycerol and water combined the advantageous of each individual solvent and resulted in high catalytic performance and efficient product extraction yield

  5. Overproduction of 2-phenylethanol by industrial yeasts to improve organoleptic properties of bakers' products.

    Science.gov (United States)

    Dueñas-Sánchez, Rafael; Pérez, Ana G; Codón, Antonio C; Benítez, Tahía; Rincón, Ana María

    2014-06-16

    2-Phenylethanol (PEA), an important alcohol derived from phenylalanine, is involved in aroma and flavour of bakers' products. Four spontaneous mutants of an industrial bakers' yeast, V1 strain, were isolated for their resistance to p-fluoro-DL-phenylalanine (PFP), a toxic analogue of L-phenylalanine. Mutants overproduced this amino acid and showed variations in their internal pool for several other amino acids. Moreover, a rise in PEA production after growth in industrial medium (MAB) was observed in three of the mutants, although their growth and fermentative capacities were slightly impaired. However, concentration of PEA remained higher during dough fermentation and also after baking, thus improving taste and aroma in bread.

  6. Effects of mill stream flours technological quality on fermentative activity of baker's yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Mirić Katarina V.

    2008-01-01

    Full Text Available This work in concerned with the interdependence between technological quality of mill stream flours and fermentative activity of baker's yeast Saccharomyces cerevisiae. Each mill stream flour has its own specific properties, determined by the particle size, technological phase of its formation and part of the wheat kernel it consists of. Biochemical complexity of dough during examination of fermentative activity of baker's yeast confirmed the influence of a number of physical and biochemical flour properties, such as ash content, wet gluten content, rheological flour properties, phytic acid content and amylograph peak viscosity. Abudance of significant flour characteristic, their interaction and different behavior in the presence of the yeast, showed diversity and variation of result within the same category of the mill stream flour.

  7. Comparison of melibiose utilizing baker's yeast strains produced by genetic engineering and classical breeding.

    Science.gov (United States)

    Vincent, S F; Bell, P J; Bissinger, P; Nevalainen, K M

    1999-02-01

    Yeast strains currently used in the baking industry cannot fully utilize the trisaccharide raffinose found in beet molasses due to the absence of melibiase (alpha-galactosidase) activity. To overcome this deficiency, the MEL1 gene encoding melibiase enzyme was introduced into baker's yeast by both classical breeding and recombinant DNA technology. Both types of yeast strains were capable of vigorous fermentation in the presence of high levels of sucrose, making them suitable for the rapidly developing Asian markets where high levels of sugar are used in bread manufacture. Melibiase expression appeared to be dosage-dependent, with relatively low expression sufficient for complete melibiose utilization in a model fermentation system.

  8. 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...

  9. Effects of MAL61 and MAL62 overexpression on maltose fermentation of baker's yeast in lean dough.

    Science.gov (United States)

    Zhang, Cui-Ying; Lin, Xue; Song, Hai-Yan; Xiao, Dong-Guang

    2015-08-01

    The predominant fermentable sugar in lean dough is maltose. To improve the leavening ability of baker's yeast in lean dough, maltose metabolism should be improved. Maltase (alpha-glucosidase, encoded by MAL62) and maltose permease (encoded by MAL61) are the major factors involved in maltose metabolism. The major rate-limiting factor in maltose metabolism and leavening ability of baker's yeast remains unclear. In this work, MAL61 and/or MAL62 overexpression strains were constructed to investigate the decisive factor for maltose metabolism of industrial baker's yeast in lean dough. Our results show that elevated maltose permease activity by MAL61 overexpression yielded less improvement in maltose fermentation compared to elevated maltase activity by MAL62 overexpression. Significant increase in maltase activity by MAL62 overexpression could result in a 44% increase in leavening ability of industrial baker's yeast in lean dough and a 39% increase in maltose metabolism in a medium containing glucose and maltose. Thus, maltase was the rate-limiting factor in maltose fermentation of industrial baker's yeast in lean dough. This study lays a foundation for breeding of industrial baker's yeast for quick dough leavening.

  10. 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.

  11. Baker's yeast mediated reduction of substituted acenaphthenequinones: Regio- and enantioselective preparation of mono-hydroxyacenaphthenones

    Institute of Scientific and Technical Information of China (English)

    Xing Yong Wang; Jing Nan Cui; Wei Min Ren; Feng Li; Chun Liang Lu; Xu Hong Qian

    2007-01-01

    Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h.By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee.

  12. Enhanced leavening ability of baker's yeast by overexpression of SNR84 with PGM2 deletion.

    Science.gov (United States)

    Lin, Xue; Zhang, Cui-Ying; Bai, Xiao-Wen; Xiao, Dong-Guang

    2015-06-01

    Dough-leavening ability is one of the main aspects considered when selecting a baker's yeast strain for baking industry. Generally, modification of maltose metabolic pathway and known regulatory networks of maltose metabolism were used to increase maltose metabolism to improve leavening ability in lean dough. In this study, we focus on the effects of PGM2 (encoding for the phosphoglucomutase) and SNR84 (encoding for the H/ACA snoRNA) that are not directly related to both the maltose metabolic pathway and known regulatory networks of maltose metabolism on the leavening ability of baker's yeast in lean dough. The results show that the modifications on PGM2 and/or SNR84 are effective ways in improving leavening ability of baker's yeast in lean dough. Deletion of PGM2 decreased cellular glucose-1-phosphate and overexpression of SNR84 increased the maltose permease activity. These changes resulted in 11, 19 and 21% increases of the leavening ability for PGM2 deletion, SNR84 overexpression and SNR84 overexpression combining deleted PGM2, respectively.

  13. 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…

  14. A simple method to detect complement receptors using baker's yeast: Y C rosettes.

    Science.gov (United States)

    Rivero, I; Abaca, H E; Vallés, R; Vannucci, J D; Diumenjo, M S; Moravenik, M B

    1979-01-01

    A technique is described to identify complement-receptor-bearing cells, using serum-treated baker's yeast as a ligand. The method consists of incubation of heat-killed baker's yeasts with fresh AB normal serum, freezing, thawing, and washing of the particles, followed by mixing with the cells. Serum is required to coat the yeasts for the rosette formation. Experiments designed to establish the serum factors responsible for the attachment of the particles to cells show that heat inactivation, chelating agents, or anti-C3 treatment prevent rosette formation. This is taken as evidence that yeasts (Y) are coated with complement (C) to compose the reagent for the YC rosette technique. The application of this technique to twenty-five normal individuals demonstrated that a mean of 11.6 per 100 lymphocytes (+/- 4.3) form rosettes; absolute number: 275 (+/- 160) rosette-forming lymphocytes per mm3. Either AB or autologous fresh serum can be used to coat the yeasts. A combined technique for YC plus E rosettes can be performed allowing the identification and enumeration of four populations of lymphocytes: (a) those having receptors for sheep erythrocytes, (b) complement-receptor-bearing lymphocytes, (c) those having both receptors (D lymphocytes), and (d) non-rosette-forming non-phagocytic cells.

  15. Post-fermentative production of glutathione by baker's yeast (S. cerevisiae) in compressed and dried forms.

    Science.gov (United States)

    Musatti, Alida; Manzoni, Matilde; Rollini, Manuela

    2013-01-25

    The study was aimed at investigating the best biotransformation conditions to increase intracellular glutathione (GSH) levels in samples of baker's yeast (Saccharomyces cerevisiae) employing either the commercially available compressed and dried forms. Glucose, GSH precursors amino acids, as well as other cofactors, were dissolved in a biotransformation solution and yeast cells were added (5%dcw). Two response surface central composite designs (RSCCDs) were performed in sequence: in the first step the influence of amino acid composition (cysteine, glycine, glutamic acid and serine) on GSH accumulation was investigated; once their formulation was set up, the influence of other components was studied. Initial GSH content was found 0.53 and 0.47%dcw for compressed and dried forms. GSH accumulation ability of baker's yeast in compressed form was higher at the beginning of shelf life, that is, in the first week, and a maximum of 2.04%dcw was obtained. Performance of yeast in dried form was not found satisfactory, as the maximum GSH level was 1.18%dcw. When cysteine lacks from the reaction solution, yeast cells do not accumulate GSH. With dried yeast, the highest GSH yields occurred when cysteine was set at 3 g/L, glycine and glutamic acid at least at 4 g/L, without serine. Employing compressed yeast, the highest GSH yields occurred when cysteine and glutamic acid were set at 2-3 g/L, while glycine and serine higher than 2 g/L. Results allowed to set up an optimal and feasible procedure to obtain GSH-enriched yeast biomass, with up to threefold increase with respect to initial content.

  16. Production of Aromatic Plant Terpenoids in Recombinant Baker's Yeast.

    Science.gov (United States)

    Emmerstorfer-Augustin, Anita; Pichler, Harald

    2016-01-01

    Plant terpenoids are high-value compounds broadly applied as food additives or fragrances in perfumes and cosmetics. Their biotechnological production in yeast offers an attractive alternative to extraction from plants. Here, we provide two optimized protocols for the production of the plant terpenoid trans-nootkatol with recombinant S. cerevisiae by either (I) converting externally added (+)-valencene with resting cells or (II) cultivating engineered self-sufficient production strains. By synthesis of the hydrophobic compounds in self-sufficient production cells, phase transfer issues can be avoided and the highly volatile products can be enriched in and easily purified from n-dodecane, which is added to the cell broth as second phase.

  17. Isolation and Kinetic Characterization of Fumarase from Baker's Yeast

    Directory of Open Access Journals (Sweden)

    Vasić-Rački, D.

    2012-05-01

    Full Text Available Isolation and purification of fumarase (fumarate hydratase EC 4.2.1.2 from baker’s yeast was carried out. Yeast cells were disrupted by three methods: glass beads, ultrasound, and the combination of these two methods. Cell disruption methods were compared in their efficiency in Fig. 1. Protein fractionation was carried out by precipitation with ammonium sulphate. The concentrations of ammonium sulphate necessary for fumarase precipitation were found ex- perimentally and are presented in Fig. 2. After precipitation, fumarase samples were purified by gel filtration chromatography on columns filled with Sephadex G50 and Sephadex G100. Examples of the elution curve of one protein suspension sample on both columns are presented in Fig. 3 and Fig. 4. Only the samples having high fumarase activity were used in the next purifying step. Table 1 presents the collective results of the fumarase purification procedure. The tech- niques used enabled purification of fumarase with a yield of 25 %. The purified enzyme was employed in the hydration of fumaric acid to L-malic acid. Kinetic constants of fumarase were estimated and are presented in Table 2. They were determined from the experimental data measured by the initial reaction rate method. The hydration of fumaric acid to L-malic acid was carried out in a batch reactor and the results are presented in Fig. 5. The kinetic model was developed on the basis of kinetic data and reaction scheme, as presented by equations 1 and 2. It was combined with the mass balances in the batch reactor presented by equations 3 and 4. Considering that fumarase deactivation occurs, it was proposed that the activity loss could be described by a first-order kinetic model (equation 5. Fumarase activity was followed during the batch experiment by the enzyme assay and it was found that activity decay occurs. Deactivation constant was estimated from the independent experimental results and found to be 0.0031 min–1.

  18. The global effect of exposing bakers' yeast to 5-fluoruracil and nystatin; a view to Toxichip.

    Science.gov (United States)

    Graziano, Sara; Gullì, Mariolina; Maestri, Elena; Marmiroli, Nelson

    2016-02-01

    A genome-wide screen of a haploid deletion library of bakers' yeast (Saccharomyces cerevisiae) was conducted to document the phenotypic and transcriptional impact of exposure to each of the two pharmaceutical products 5-fluorouracil (an anti-tumor agent) and nystatin (an anti-fungal agent). The combined data set was handled by applying a systems biology perspective. A Gene Ontology analysis identified functional categories previously characterized as likely targets for both compounds. Induced transcription profiles were well correlated in yeast and human HepG2 cells. The identified molecular targets for both compounds were used to suggest a small set of human orthologues as appropriate for testing on human material. The yeast system developed here (denoted "Toxichip") has likely utility for identifying biomarkers relevant for health and environmental risk assessment applications required as part of the development process for novel pharmaceuticals.

  19. Regio- and Stereo-selective Bioreduction of Diketo-n-butylphosphonate by Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    WANG,Ke(王科); LI,Jin-Feng(李晋峰); YUAN,Cheng-Ye(袁承业); LI,Zu-Yi(李祖义)

    2002-01-01

    A regio- and stereo-selective reduction of diketo-n-butylphos-phonates by baker's yeast was reported. The chemical yield and ee value of these reactions are highly dependent on the structure of substrates. the resulting optical active hydroxyalkanephosphonates can be used as chirons for the synthesis of polyfunctional organophosphorus compounds. As useful building block, a series of α,β-unsaturated ketones bearing chiral hydroxy group in addition to trifluoromethyl moiety was prepared via the Horner-Wadsorth-Emmons (HWE) reaction of the biotransformation products.

  20. Genetic engineering of baker's and wine yeasts using formaldehyde hyperresistance-mediating plasmids

    Directory of Open Access Journals (Sweden)

    Schmidt M.

    1997-01-01

    Full Text Available Yeast multi-copy vectors carrying the formaldehyde-resistance marker gene SFA have proved to be a valuable tool for research on industrially used strains of Saccharomyces cerevisiae. The genetics of these strains is often poorly understood, and for various reasons it is not possible to simply subject these strains to protocols of genetic engineering that have been established for laboratory strains of S. cerevisiae. We tested our vectors and protocols using 10 randomly picked baker's and wine yeasts all of which could be transformed by a simple protocol with vectors conferring hyperresistance to formaldehyde. The application of formaldehyde as a selecting agent also offers the advantage of its biodegradation to CO2 during fermentation, i.e., the selecting agent will be consumed and therefore its removal during down-stream processing is not necessary. Thus, this vector provides an expression system which is simple to apply and inexpensive to use

  1. An improved, bias-reduced probabilistic functional gene network of baker's yeast, Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Insuk Lee

    Full Text Available BACKGROUND: Probabilistic functional gene networks are powerful theoretical frameworks for integrating heterogeneous functional genomics and proteomics data into objective models of cellular systems. Such networks provide syntheses of millions of discrete experimental observations, spanning DNA microarray experiments, physical protein interactions, genetic interactions, and comparative genomics; the resulting networks can then be easily applied to generate testable hypotheses regarding specific gene functions and associations. METHODOLOGY/PRINCIPAL FINDINGS: We report a significantly improved version (v. 2 of a probabilistic functional gene network of the baker's yeast, Saccharomyces cerevisiae. We describe our optimization methods and illustrate their effects in three major areas: the reduction of functional bias in network training reference sets, the application of a probabilistic model for calculating confidences in pair-wise protein physical or genetic interactions, and the introduction of simple thresholds that eliminate many false positive mRNA co-expression relationships. Using the network, we predict and experimentally verify the function of the yeast RNA binding protein Puf6 in 60S ribosomal subunit biogenesis. CONCLUSIONS/SIGNIFICANCE: YeastNet v. 2, constructed using these optimizations together with additional data, shows significant reduction in bias and improvements in precision and recall, in total covering 102,803 linkages among 5,483 yeast proteins (95% of the validated proteome. YeastNet is available from http://www.yeastnet.org.

  2. Evaluation of baker's yeast in honey using a real-time PCR assay.

    Science.gov (United States)

    Kast, Christina; Roetschi, Alexandra

    2017-04-01

    Occasionally, melissopalynological analysis reveals the presence of baker's yeast (Saccharomyces cerevisiae) in honey sediments. A field experiment reproducing a common spring bee feeding practice, using sugar paste containing baker's yeast, was performed to understand how S. cerevisiae are introduced into honey. Apart from classical microscopy, a real-time quantitative PCR (qPCR) system specific for S. cerevisiae was established for quantification of S. cerevisiae in honeys. Results showed that S. cerevisiae cells are stored in the honey of the brood combs and are also transferred into honey in the supers. The concentrations of S. cerevisiae were highest in honey of the brood frames immediately after the feeding and decreased over time to low concentrations at the end of the year. A high content of S. cerevisiae cells were also found in the honey from supers of the spring harvest. Observed S. cerevisiae cells were not able to multiply in a high-sugar environment, such as honey, and their viability decreased rapidly after addition to the honey. The screening of 200 Swiss honeys revealed the presence of S. cerevisiae in 4.5% of the samples, as determined by microscopy and qPCR. Finally, the method described here may indicate an unwanted sucrose addition to honey through bee-feeding.

  3. Sugar utilization patterns and respiro-fermentative metabolism in the baker's yeast Torulaspora delbrueckii.

    Science.gov (United States)

    Alves-Araújo, C; Pacheco, A; Almeida, M J; Spencer-Martins, I; Leão, C; Sousa, M J

    2007-03-01

    The highly osmo- and cryotolerant yeast species Torulaspora delbrueckii is an important case study among the non-Saccharomyces yeast species. The strain T. delbrueckii PYCC 5321, isolated from traditional corn and rye bread dough in northern Portugal, is considered particularly interesting for the baking industry. This paper reports the sugar utilization patterns of this strain, using media with glucose, maltose and sucrose, alone or in mixtures. Kinetics of growth, biomass and ethanol yields, fermentation and respiration rates, hydrolase activities and sugar uptake rates were used to infer the potential applied relevance of this yeast in comparison to a conventional baker's strain of Saccharomyces cerevisiae. The results showed that both maltase and maltose transport in T. delbrueckii were subject to glucose repression and maltose induction, whereas invertase was subject to glucose control but not dependent on sucrose induction. A comparative analysis of specific sugar consumption rates and transport capacities suggests that the transport step limits both glucose and maltose metabolism. Specific rates of CO(2) production and O(2) consumption showed a significantly higher contribution of respiration to the overall metabolism in T. delbrueckii than in S. cerevisiae. This was reflected in the biomass yields from batch cultures and could represent an asset for the large-scale production of the former species. This work contributes to a better understanding of the physiology of a non-conventional yeast species, with a view to the full exploitation of T. delbrueckii by the baking industry.

  4. Construction from a single parent of baker's yeast strains with high freeze tolerance and fermentative activity in both lean and sweet doughs.

    Science.gov (United States)

    Nakagawa, S; Ouchi, K

    1994-10-01

    From a freeze-tolerant baker's yeast (Saccharomyces cerevisiae), 2,333 spore clones were obtained. To improve the leavening ability in lean dough of the parent strain, we selected 555 of the high-maltose-fermentative spore clones by using a method in which a soft agar solution containing maltose and bromocresol purple was overlaid on yeast colonies. By measuring the gassing power in the dough, we selected 66 spore clones with a good leavening ability in lean dough and a total of 694 hybrids were constructed by crossing them. Among these hybrids, we obtained 50 novel freeze-tolerant strains with good leavening ability in all lean, regular, and sweet doughs comparable to that of commercial baker's yeast. Hybrids with improved leavening ability or freeze tolerance compared with the parent yeast and commercial baker's yeasts were also obtained. These results suggest that hybridization between spore clones derived from a single parent strain is effective for improving the properties of baker's yeasts.

  5. The Isolation of Invertase from Baker's Yeast: A Four-Part Exercise in Protein Purification and Characterization

    Science.gov (United States)

    Timerman, Anthony P.; Fenrick, Angela M.; Zamis, Thomas M.

    2009-01-01

    A sequence of exercises for the isolation and characterization of invertase (E.C. 3.1.2.26) from baker's yeast obtained from a local grocery store is outlined. Because the enzyme is colorless, the use of colored markers and the sequence of purification steps are designed to "visualize" the process by which a colorless protein is selectively…

  6. Preparation of iron-enriched baker's yeast and its efficiency in recovery of rats from dietary iron deficiency

    OpenAIRE

    Kyyaly, Mohammad Aref; Powell, Chris; Ramadan, Elshahat

    2015-01-01

    OBJECTIVES Iron is an important mineral, essential for the health and function of mammalian cells. Despite its key role, iron deficiency in humans is common worldwide, often leading to significant health issues within the population. The aim of this study was to evaluate the potential of using iron-enriched baker's yeast as a source of iron, especially for the protection and recovery from conditions related to anemia. METHODS Iron-enriched yeast was prepared by cultivating cells o...

  7. Baker's yeast effluent as a liquid feed for dairy cows and heifers.

    Science.gov (United States)

    Blauwiekel, R; Loney, K A; Riley, R E

    1995-02-01

    Liquid effluent from baker's yeast production was fed to dairy cows to determine whether effluent is an acceptable feed and whether it affects milk yield or composition. Effluent averaged 5.4% DM and 6.1% N (DM basis). In experiment 1, 20 Holstein cows were offered effluent free choice or no effluent for 8 wk. Milk yield, composition, and group feed intake were measured. In Experiment 2, 20 cows were fed effluent blended into the TMR (11.3 L/d per cow) or no effluent for 4 wk. In Experiment 3, six groups of 6 heifers were offered free choice or no effluent. Free choice intake of effluent peaked at 15 L/d per cow at wk 3 but declined to 5.3 L/d per cow by wk 6. Milk and 3.5% FCM yields were not affected by effluent regardless of feeding system. Milk protein and fat percentages were higher for cows offered effluent free choice. Milk protein percentage and yield were lower with effluent in the TMR. Intake of effluent by heifers was 1.05 L/d, and effluent did not affect DMI or weight gain. Acceptability of yeast effluent fed free choice is poor, but when yeast is blended into the TMR, cows consume effluent without adverse effects on milk yield or DMI.

  8. Disruption of phospholipase B gene, PLB1, increases the survival of baker's yeast Torulaspora delbrueckii.

    Science.gov (United States)

    Watanabe, Y; Imai, K; Oishi, H; Tamai, Y

    1996-12-15

    An uracil auxotrophic mutant of baker's yeast Torulaspora delbrueckii, which is resistant to 5-fluoro-orotic acid, was complemented by transformation with YEp24 which harbors 2 microns origin and URA3 derived from Saccharomyces cerevisiae. The phospholipase B in T. delbrueckii cells is active in both acidic and alkaline conditions. However, activity of phospholipase B gene (PLB1) in cells of disruption mutant (plb1:: URA3) was lost in both conditions, which indicates that all phospholipase B activity is encoded by a single gene (or a single polypeptide) in these yeast cells. Over-expression of PLB1 with YEp plasmid vector in T. delbrueckii cells showed approximately 2.5-fold increase in phospholipase B activity, comparing with that in wild-type cells. Cells of plb1 delta mutant showed increased survival when cells of plb1 delta mutant and wild-type strain were incubated in water at 30 degrees C. Cells of PLB1-over-expressed strain died rapidly even during the cultivation period, indicating that phospholipase B activity may be a determinant for the survival of this yeast.

  9. Utilization of baker's yeast (Saccharomyces cerevisiae for the production of yeast extract: effects of different enzymatic treatments on solid, protein and carbohydrate recovery

    Directory of Open Access Journals (Sweden)

    TATJANA VUKASINOVIC MILIC

    2007-05-01

    Full Text Available Yeast extract (YE was produced from commercial pressed baker's yeast (active and inactivated using two enzymes: papain and lyticase. The effects of enzyme concentration and hydrolysis time on the recovery of solid, protein and carbohydrate were investigated. Autolysis, as a basic method for cell lysis was also used and the results compared. The optimal extraction conditions were investigated. The optimal concentrations of papain and lyticase were found to be 2.5 % and 0.025 %, respectively.

  10. Improvement of fermentation ability under baking-associated stress conditions by altering the POG1 gene expression in baker's yeast.

    Science.gov (United States)

    Sasano, Yu; Haitani, Yutaka; Hashida, Keisuke; Oshiro, Satoshi; Shima, Jun; Takagi, Hiroshi

    2013-08-01

    During the bread-making process, yeast cells are exposed to many types of baking-associated stress. There is thus a demand within the baking industry for yeast strains with high fermentation abilities under these stress conditions. The POG1 gene, encoding a putative transcription factor involved in cell cycle regulation, is a multicopy suppressor of the yeast Saccharomyces cerevisiae E3 ubiquitin ligase Rsp5 mutant. The pog1 mutant is sensitive to various stresses. Our results suggested that the POG1 gene is involved in stress tolerance in yeast cells. In this study, we showed that overexpression of the POG1 gene in baker's yeast conferred increased fermentation ability in high-sucrose-containing dough, which is used for sweet dough baking. Furthermore, deletion of the POG1 gene drastically increased the fermentation ability in bread dough after freeze-thaw stress, which would be a useful characteristic for frozen dough baking. Thus, the engineering of yeast strains to control the POG1 gene expression level would be a novel method for molecular breeding of baker's yeast.

  11. The three zinc-containing alcohol dehydrogenases from baker's yeast, Saccharomyces cerevisiae.

    Science.gov (United States)

    Leskovac, Vladimir; Trivić, Svetlana; Pericin, Draginja

    2002-12-01

    This review is a summary of our current knowledge of the structure, function and mechanism of action of the three zinc-containing alcohol dehydrogenases, YADH-1, YADH-2 and YADH-3, in baker's yeast, Saccharomyces cerevisiae. The opening section deals with the substrate specificity of the enzymes, covering the steady-state kinetic data for its most known substrates. In the following sections, the kinetic mechanism for this enzyme is reported, along with the values of all rate constants in the mechanism. The complete primary structures of the three isoenzymes of YADH are given, and the model of the 3D structure of the active site is presented. All known artificial mutations in the primary structure of the YADH are covered in full and described in detail. Further, the chemical mechanism of action for YADH is presented along with the complement of steady-state and ligand-binding data supporting this mechanism. Finally, the bio-organic chemistry of the hydride-transfer reactions catalyzed by the enzyme is covered: this chemistry explains the narrow substrate specificity and the enantioselectivity of the yeast enzyme.

  12. Prevention of GABA reduction during dough fermentation using a baker's yeast dal81 mutant.

    Science.gov (United States)

    Ando, Akira; Nakamura, Toshihide

    2016-10-01

    γ-Aminobutyric acid (GABA) is consumed by yeasts during fermentation. To prevent GABA reduction in bread dough, a baker's yeast mutant AY77 deficient in GABA assimilation was characterized and utilized for wheat dough fermentation. An amber mutation in the DAL81 gene, which codes for a positive regulator of multiple nitrogen degradation pathways, was found in the AY77 strain. The qPCR analyses of genes involved in nitrogen utilization showed that transcriptional levels of the UGA1 and DUR3 genes encoding GABA transaminase and urea transporter, respectively, are severely decreased in the AY77 cells. The AY77 strain cultivated by fed-batch culture using cane molasses exhibited inferior gas production during dough fermentation compared to that of wild-type strain AY13. However, when fed with molasses containing 0.5% ammonium sulfate, the mutant strain exhibited gas production comparable to that of the AY13 strain. In contrast to the AY13 strain, which completely consumed GABA in dough within 5 h, the AY77 strain consumed no GABA under either culture condition. Dough fermentation with the dal81 mutant strain should be useful for suppression of GABA reduction in breads.

  13. The comparison of Cu(Ⅱ) adsorption capability of baker's yeast, nano-titania and their composite adsorbent

    Institute of Scientific and Technical Information of China (English)

    ZHANG YunSong; WANG RenGuo; WANG XianXiang; LEI SanZhong; TONG DongMei

    2008-01-01

    The anatase nano-TiO2 powder, with crystal size between 40 and 80 nm, was prepared by the liquid phase hydrolysis of TiOCI4. At the same time, the nano-TiO2was utilized with the baker's yeast biomass as a composite adsorbent to adsorb the Cu ions in the artificial aqueous solution. The investigation showed that the composite adsorbent had a fine adsorption efficiency. The TiO2 in the composite ad-sorbent could cooperate well with baker's yeast to improve the adsorbing capability of Cu2+ under the following experimental conditions as well: a quantity of composite adsorbent of 5 g·L-1, pH≥4.0, an adsorption time of 40 rain and an initial concentration of Cu ions of 10 mg·L-1. In addition, the results of measurements, obtained with a scanning electron microscope, an infrared spectrophotometer and a Zeta potential analyzer, revealed that the baker's yeast and nano-TiO2 produced the composite ad-sorbent through coordination and hydrogen bonds in particular, etc. The stability of the composite adsorbent and the amount of titania loaded were largely dependent on the concentration of hydrogen ion in the solution.

  14. On-line optimal control for fed-batch culture of baker's yeast production

    Energy Technology Data Exchange (ETDEWEB)

    Wu, W.T.; Chen, K.C.; Chiou, H.W.

    1985-05-01

    A method of on-line optimal control for fed-batch culture of bakers yeast production is proposed. The feed rate is taken as the control variable. The specific growth rate of the yeast is the output variable and is determined from the balance equation of oxygen. A moving model is obtained by using the data from the feed rate and the specific growth rate. Based on the moving model, an optimal feed rate for fed-batch culture is then achieved. 11 references.

  15. Superior molasses assimilation, stress tolerance, and trehalose accumulation of baker's yeast isolated from dried sweet potatoes (hoshi-imo).

    Science.gov (United States)

    Nishida, Osamu; Kuwazaki, Seigo; Suzuki, Chise; Shima, Jun

    2004-07-01

    Yeast strains were isolated from dried sweet potatoes (hoshi-imo), a traditional preserved food in Japan. Dough fermentation ability, freeze tolerance, and growth rates in molasses, which are important characteristics of commercial baker's yeast, were compared between these yeast strains and a commercial yeast derivative that had typical characteristics of commercial strains. Classification tests including pulse-field gel electrophoresis and fermentation/assimilation ability of sugars showed that almost the stains isolated belonged to Saccharomyces cerevisiae. One strain, ONY1, accumulated intracellular trehalose at a higher level than commercial strain T128. Correlated with intracellular trehalose contents, the fermentation ability of high-sugar dough containing ONY1 was higher. ONY1 also showed higher freeze tolerance in both low-sugar and high-sugar doughs. The growth rate of ONY1 was significantly higher under batch and fed-batch cultivation conditions using either molasses or synthetic medium than that of strain T128. These results suggest that ONY1 has potential commercial use as baker's yeast for frozen dough and high-sugar dough.

  16. Treatment of the baker's yeast wastewater by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Kobya, M. [Department of Environmental Engineering, Gebze Institute of Technology, 41400 Gebze (Turkey)], E-mail: kobya@gyte.edu.tr; Delipinar, S. [Department of Environmental Engineering, Gebze Institute of Technology, 41400 Gebze (Turkey)

    2008-06-15

    In the laboratory-scale experiments, treatment of baker's yeast production wastewater has been investigated by electrocoagulation (EC) using a batch reactor. Effects of the process variables such as pH, electrode material (Fe and Al), current density, and operating time are investigated in terms of removal efficiencies of chemical oxygen demand (COD), total organic carbon (TOC), turbidity, and operating cost, respectively. The maximum removal efficiencies of COD, TOC and turbidity under optimal operating conditions, i.e., pH 6.5 for Al electrode and pH 7 for Fe electrode, current density of 70 A/m{sup 2} and operating time of 50 min were 71, 53 and 90% for Al electrode and 69, 52 and 56% for Fe electrode, respectively. Al electrode gave 4.4 times higher removal efficiency of turbidity than Fe electrode due to interference from color of dissolved iron. The operating costs for Al and Fe electrodes in terms of $/m{sup 3} or $/kg COD were 1.54 and 0.82, 0.51 and 0.27, respectively.

  17. Enhancement of the proline and nitric oxide synthetic pathway improves fermentation ability under multiple baking-associated stress conditions in industrial baker's yeast

    Directory of Open Access Journals (Sweden)

    Sasano Yu

    2012-04-01

    Full Text Available Abstract Background During the bread-making process, industrial baker's yeast, mostly Saccharomyces cerevisiae, is exposed to baking-associated stresses, such as air-drying and freeze-thaw stress. These baking-associated stresses exert severe injury to yeast cells, mainly due to the generation of reactive oxygen species (ROS, leading to cell death and reduced fermentation ability. Thus, there is a great need for a baker's yeast strain with higher tolerance to baking-associated stresses. Recently, we revealed a novel antioxidative mechanism in a laboratory yeast strain that is involved in stress-induced nitric oxide (NO synthesis from proline via proline oxidase Put1 and N-acetyltransferase Mpr1. We also found that expression of the proline-feedback inhibition-less sensitive mutant γ-glutamyl kinase (Pro1-I150T and the thermostable mutant Mpr1-F65L resulted in an enhanced fermentation ability of baker's yeast in bread dough after freeze-thaw stress and air-drying stress, respectively. However, baker's yeast strains with high fermentation ability under multiple baking-associated stresses have not yet been developed. Results We constructed a self-cloned diploid baker's yeast strain with enhanced proline and NO synthesis by expressing Pro1-I150T and Mpr1-F65L in the presence of functional Put1. The engineered strain increased the intracellular NO level in response to air-drying stress, and the strain was tolerant not only to oxidative stress but also to both air-drying and freeze-thaw stresses probably due to the reduced intracellular ROS level. We also showed that the resultant strain retained higher leavening activity in bread dough after air-drying and freeze-thaw stress than that of the wild-type strain. On the other hand, enhanced stress tolerance and fermentation ability did not occur in the put1-deficient strain. This result suggests that NO is synthesized in baker's yeast from proline in response to oxidative stresses that induce ROS

  18. Identification of genes whose expressions are enhanced or reduced in baker's yeast during fed-batch culture process using molasses medium by DNA microarray analysis.

    Science.gov (United States)

    Shima, Jun; Kuwazaki, Seigo; Tanaka, Fumiko; Watanabe, Hajime; Yamamoto, Hideki; Nakajima, Ryoichi; Tokashiki, Tadaaki; Tamura, Hiromi

    2005-06-25

    Genes whose expression levels are enhanced or reduced during the cultivation process that uses cane molasses in baker's yeast production were identified in this study. The results showed that baker's yeast grown in molasses medium had higher fermentation ability and stress tolerance compared with baker's yeast grown in synthetic medium. Molasses apparently provided not only sugar as a carbon source but also provided functional components that enhanced or reduced expression of genes involved in fermentation ability and stress tolerance. To identify the genes whose expression is enhanced or reduced during cultivation in molasses medium, DNA microarray analysis was then used to compare the gene expression profile of cells grown in molasses with that of cells grown in synthetic medium. To simulate the commercial baker's yeast production process, cells were cultivated using a fed-batch culture system. In molasses medium, genes involved in the synthesis or uptake of vitamins (e.g., biotin, pyridoxine and thiamine) showed enhanced expression, suggesting that vitamin concentrations in molasses medium were lower than those in synthetic medium. Genes involved in formate dehydrogenase and maltose assimilation showed enhanced expression in molasses medium. In contrast, genes involved in iron utilization (e.g., siderophore, iron transporter and ferroxidase) showed enhanced expression in synthetic medium, suggesting that iron starvation occurred. The genes involved in the metabolism of amino acids also showed enhanced expression in synthetic medium. This identification of genes provides information that will help improve the baker's yeast production process.

  19. Research progress on improvement in freeze-tolerance of baker's yeast%提高面包酵母耐冷冻性的研究进展

    Institute of Scientific and Technical Information of China (English)

    苏从毅; 王辛; 王四维; 张福钊

    2012-01-01

    Baker yeast is a necessary material of bread making, and improvement in freeze- tolerance of baker's yeast is very important to the development of frozen dough. In this paper, the species and effects of baker's yeast were introduced, and the freeze-tolerance mechanism of baker's yeast and the development review on improvement in freeze-tolerance of baker's yeast were emphasized.%面包酵母是制作面包不可缺少的原料,提高面包酵母的耐冷冻性对冷冻面团工业的发展有着十分重要的作用。本文介绍了面包酵母的种类和作用,重点讲述了面包酵母的耐冷冻机理及国内外对提高面包酵母耐冷冻性的研究进展。

  20. Variation in fatty acid composition of Artemia salina nauplii enriched with microalgae and baker's yeast for use in larviculture.

    Science.gov (United States)

    Chakraborty, Rekha D; Chakraborty, Kajal; Radhakrishnan, E V

    2007-05-16

    The high content of the essential fatty acids in some microalgae and baker's yeast has made them excellent diets for boosting the fatty acid content of livefood Artemia. The influences of baker's yeast (Saccharomyces cerevisiae) and three microalgae, viz., Chlorella salina, Chaetoceros calcitrans, and Nannochloropsis salina, were tested as diet components in marine livefeed brine shrimp Artemia salina nauplii to improve the polyunsaturated fatty acid (PUFA) composition. Artemia nauplii submerged in these diets for four different enrichment intervals (3, 6, 8, and 24 h) were found to incorporate essential fatty acids, and the percentage composition of different fatty acids was measured in the enriched Artemia nauplii and enrichment diets. N. salina produced higher levels of arachidonic acid (AA, 20:4n6, 9.50%), eicosapentaenoic acid (EPA, 20:5n3, 25.80%), and docosahexaenoic acid (DHA, 22:6n3, 4.18%) as compared to other diets. The total PUFA content of the enriched Artemia by N. salina increased by 56.50% with enrichment periods up to 8 h, followed by a significant reduction in the final 24 h. N. salina yielded Artemia nauplii with considerable EPA (8.05%), AA (14.15%), and DHA (1.85%) after 8 h of enrichment, which are significantly higher levels than in nauplii fed with the other three diets (p = 0.05). The DHA/EPA values in Artemia enriched for 6 h by N. salina and C. calcitrans were found to be, respectively, 88.46 and 25% higher than freshly hatched Artemia. Artemia enriched by C. salina and baker's yeast exhibited a reduction in PUFA content even at 6 h of enrichment. Significant relative decreases in DHA, EPA, and total PUFA in Artemia enriched with all of the diets were apparent, with a corresponding increase in the total saturated fatty acid content (26.95 +/- 9.75%) in the final stages (24 h) of enrichment (p = 0.05).

  1. 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.

    Science.gov (United States)

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

    2015-01-01

    Yeast is frequently used as a probiotic in aquaculture with the potential to substitute for antibiotics. 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. No yeast, live yeast or heat-inactivated baker's yeast were added to basal diets high in fishmeal and low in soybean (diet A) or low in fishmeal and high in soybean (diet B), which were fed to fish for 8 weeks. Growth, feed utilization, gut microvilli morphology, and expressions of hsp70 and inflammation-related cytokines in the intestine and head kidney were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Gut alkaline phosphatase (AKP) activity was measured after challenging the fish with Aeromonas hydrophila. Results showed that live yeast significantly improved FBW and WG (P yeast). No significant differences were observed between inactivated yeast and control. Live yeast improved gut microvilli length (P yeast did not. The hsp70 expression level in both the intestine and head kidney of fish was significantly reduced by live yeast (P yeast. Live yeast but not inactivated yeast reduced intestinal expression of tnfα (P Intestinal Lactococcus spp. numbers were enriched by both live and inactivated yeast. Lastly, both live and inactivated yeast reduced the gut AKP activity compared to the control (P yeast. Nevertheless, secretory metabolites were the major contributing factor towards improved gut microvilli morphology, relieved stress status, and reduced intestinal inflammation of Nile tilapia fed diets supplemented with baker's yeast.

  2. Reduções enantiosseletivas de cetonas utilizando-se fermento de pão Enantioselective reductions of ketones using baker's yeast

    Directory of Open Access Journals (Sweden)

    José Augusto R. Rodrigues

    2001-12-01

    Full Text Available Baker's yeast has been successful employed to reduce carbonyl compounds carrying appropriated substituents at distances under the electronic influence of the keto group. High yields and enantiomeric excess (ee were obtained with 1,2-alkanedione, 1,2-alkanedione (2-O-methyloxime and 1,3-alkanedione. Potential chiral building blocks were obtained and applied for stereoselective synthesis of valuable compounds. Evidence for a free radical chain process was obtained with baker's yeast reduction of a-iodoacetophenone using radical inhibitors.

  3. Beta-glucan-depleted, glycopeptide-rich extracts from Brewer's and Baker's yeast (Saccharomyces cerevisiae) lower interferon-gamma production by stimulated human blood cells in vitro.

    Science.gov (United States)

    Williams, Roderick; Dias, Daniel A; Jayasinghe, Nirupama; Roessner, Ute; Bennett, Louise E

    2016-04-15

    Regulation of the human immune system requires controlled pro- and anti-inflammatory responses for host defence against infection and disease states. Yeasts (Saccharomyces cerevisiae), as used in brewing and baking, are mostly known for ability to stimulate the human immune-system predominantly reflecting the pro-inflammatory cell wall β-glucans. However, in this study, using food-compatible processing methods, glycopeptide-enriched and β-glucan-depleted products were each prepared from Brewer's and Baker's yeasts, which suppressed production of interferon-γ (IFN-γ) in human whole blood cell assay, signifying that anti-inflammatory factors are also present in yeast. Anti-inflammatory bioactivities of products prepared from Brewer's and Baker's yeast were compared with the commercial yeast product, Epicor®. While unfractionated Epicor was inactive, the C18 resin-binding fractions of Brewer's and Baker's yeast products and Epicor dose-dependently lowered IFN-γ, demonstrating that Epicor also contained both pro-inflammatory (β-glucans) and anti-inflammatory components. Anti-inflammatory activity was attributed to C18 resin-binding species glyco-peptides in Epicor and experimental yeast products. This study demonstrated that pro- and anti-inflammatory factors could be resolved and enriched in yeasts by suitable processing, with potential to improve specific activities.

  4. Application of fuzzy reasoning to control of glucose and ethanol concentrations in baker's yeast culture

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.S.; Shi Zhongping; Shiba, Sumihisa; Chantal, C.; Iijima, Shinji; Kobayashi, Takeshi (Dept. of Biotechnology, Nagoya Univ. (Japan))

    1993-02-01

    Fuzzy reasoning was applied to control both ethanol and glucose concentrations in fed-batch cultures of baker's yeast. This fuzzy controller consisted of three membership functions (concentrations of dissolved oxygen (DO), ethanol and glucose) and 18 production rules. Fuzzy inference was carried out by IF [l brace]A is a and B is b, ...[r brace], THEN [l brace]C is c[r brace] from the on-line measured concentrations of DO, ethanol and glucose. When 'medium' concentrations of ethanol and glucose in fed-batch culture of baker's yeast were set at 2 g/l and 0.2 g/l, both ethanol and glucose concentrations were controlled at 2.67[+-]0.35 g/l and 0.27[+-]0.25 g/l, respectively, ethanol production was reduced from 26 g/l to 3-4 g/l, cell yield increased from 0.38 to 0.53 g dry cell/g consumed glucose and ethanol yield decreased from 0.50 to 0.14 g ethanol/g consumed glucose, respectively, as compared with those of the glucose only control at 0.2 g/l. (orig.).

  5. Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production.

    Science.gov (United States)

    López-Alvarez, Arnoldo; Díaz-Pérez, Alma Laura; Sosa-Aguirre, Carlos; Macías-Rodríguez, Lourdes; Campos-García, Jesús

    2012-05-01

    In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production.

  6. Global expression studies in baker's yeast reveal target genes for the improvement of industrially-relevant traits: the cases of CAF16 and ORC2

    Directory of Open Access Journals (Sweden)

    Randez-Gil Francisca

    2010-07-01

    Full Text Available Abstract Background Recent years have seen a huge growth in the market of industrial yeasts with the need for strains affording better performance or to be used in new applications. Stress tolerance of commercial Saccharomyces cerevisiae yeasts is, without doubt, a trait that needs improving. Such trait is, however, complex, and therefore only in-depth knowledge of their biochemical, physiological and genetic principles can help us to define improvement strategies and to identify the key factors for strain selection. Results We have determined the transcriptional response of commercial baker's yeast cells to both high-sucrose and lean dough by using DNA macroarrays and liquid dough (LD model system. Cells from compressed yeast blocks display a reciprocal transcription program to that commonly reported for laboratory strains exposed to osmotic stress. This discrepancy likely reflects differences in strain background and/or experimental design. Quite remarkably, we also found that the transcriptional response of starved baker's yeast cells was qualitatively similar in the presence or absence of sucrose in the LD. Nevertheless, there was a set of differentially regulated genes, which might be relevant for cells to adapt to high osmolarity. Consistent with this, overexpression of CAF16 or ORC2, two transcriptional factor-encoding genes included in this group, had positive effects on leavening activity of baker's yeast. Moreover, these effects were more pronounced during freezing and frozen storage of high-sucrose LD. Conclusions Engineering of differentially regulated genes opens the possibility to improve the physiological behavior of baker's yeast cells under stress conditions like those encountered in downstream applications.

  7. Asymmetric bioreduction of acetophenones by Baker's yeast and its cell-free extract encapsulated in sol-gel silica materials

    Science.gov (United States)

    Kato, Katsuya; Nakamura, Hitomi; Nakanishi, Kazuma

    2014-02-01

    Baker's yeast (BY) encapsulated in silica materials was synthesized using a yeast cell suspension and its cell-free extract during a sol-gel reaction of tetramethoxysilane with nitric acid as a catalyst. The synthesized samples were fully characterized using various methods, such as scanning electron microscopy, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, thermogravimetry, and differential thermal analysis. The BY cells were easily encapsulated inside silica-gel networks, and the ratio of the cells in the silica gel was approximately 75 wt%, which indicated that a large volume of BY was trapped with a small amount of silica. The enzyme activity (asymmetric reduction of prochiral ketones) of BY and its cell-free extract encapsulated in silica gel was investigated in detail. The activities and enantioselectivities of free and encapsulated BY were similar to those of acetophenone and its fluorine derivatives, which indicated that the conformation structure of BY enzymes inside silica-gel networks did not change. In addition, the encapsulated BY exhibited considerably better solvent (methanol) stability and recyclability compared to free BY solution. We expect that the development of BY encapsulated in sol-gel silica materials will significantly impact the industrial-scale advancement of high-efficiency and low-cost biocatalysts for the synthesis of valuable chiral alcohols.

  8. Construction of a Trp- commercial baker's yeast strain by using food-safe-grade dominant drug resistance cassettes.

    Science.gov (United States)

    Estruch, Francisco; Prieto, José Antonio

    2003-12-01

    We have designed a food-safe-grade module for gene disruptions in commercial baker's yeast strains, which contains the G418 resistance cassette, KanMX4, flanked by direct repeats from the MEL1 gene of Saccharomyces cerevisiae. This module was used to obtain a Trp(-) auxotrophic mutant of the polyploid HY strain by successive targeting to the TRP1 locus and later in vivo excision of the kan(r) marker. Southern blot analysis indicated that HY contains five copies of the TRP1 gene. However, after four disruption rounds, a strain named HYtrpM(4), unable to grow in the absence of tryptophan, was selected. Southern and Northern analysis of HYtrpM(4) cells showed that a remaining functional wild-type copy was still present, suggesting that the level of phosphoribosylanthranylate isomerase activity, resulting from a single copy of TRP1, is too low to sustain growth. Accordingly, a high reversion frequency of the Trp(-) phenotype, through gene conversion, was found in cells of the mutant strain. Nevertheless, this was not a drawback for its use as a recipient strain of heterologous genes. Indeed, YEpACT-X24 transformants were stable after 25 generations and expressed and secreted high levels of active recombinant xylanase. These data indicate that the new Trp(-) strain can be used to generate a stable recombinant yeast that fulfils all the requirements and market criteria for commercial utilisation.

  9. 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.

    Directory of Open Access Journals (Sweden)

    Chao Ran

    Full Text Available Yeast is frequently used as a probiotic in aquaculture with the potential to substitute for antibiotics. 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. No yeast, live yeast or heat-inactivated baker's yeast were added to basal diets high in fishmeal and low in soybean (diet A or low in fishmeal and high in soybean (diet B, which were fed to fish for 8 weeks. Growth, feed utilization, gut microvilli morphology, and expressions of hsp70 and inflammation-related cytokines in the intestine and head kidney were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Gut alkaline phosphatase (AKP activity was measured after challenging the fish with Aeromonas hydrophila. Results showed that live yeast significantly improved FBW and WG (P < 0.05, and tended to improve FCR (P = 0.06 of fish compared to the control (no yeast. No significant differences were observed between inactivated yeast and control. Live yeast improved gut microvilli length (P < 0.001 and density (P < 0.05 while inactivated yeast did not. The hsp70 expression level in both the intestine and head kidney of fish was significantly reduced by live yeast (P < 0.05 but not inactivated yeast. Live yeast but not inactivated yeast reduced intestinal expression of tnfα (P < 0.05, tgfβ (P < 0.05 under diet A and il1β (P = 0.08. Intestinal Lactococcus spp. numbers were enriched by both live and inactivated yeast. Lastly, both live and inactivated yeast reduced the gut AKP activity compared to the control (P < 0.001, indicating protection of the host against infection by A. hydrophila. In conclusion, secretory metabolites did not play major roles in the growth promotion and disease protection effects of yeast. Nevertheless, secretory metabolites were the major contributing factor towards improved gut

  10. Physical, functional and structural characterization of the cell wall fractions from baker's yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Borchani, Chema; Fonteyn, Fabienne; Jamin, Guilhem; Paquot, Michel; Thonart, Philippe; Blecker, Christophe

    2016-03-01

    The yeast cell wall of Saccharomyces cerevisiae is an important source of β-d-glucan, a glucose homopolymer with many functional, nutritional and human health benefits. In the present study, the yeast cell wall fractionation process involving enzymatic treatments (savinase and lipolase enzymes) affected most of the physical and functional characteristics of extracted fractions. Thus, the fractionation process showed that β-d-glucan fraction F4 had significantly higher swelling power and fat binding capacity compared to other fractions (F1, F2 and F3). It also exhibited a viscosity of 652.12mPas and a high degree of brightness of extracted β-d-glucan fraction. Moreover, the fractionation process seemed to have an effect on structural and thermal properties of extracted fractions. Overall, results showed that yeast β-d-glucan had good potential for use as a prebiotic ingredient in food, as well as medicinal and pharmaceutical products.

  11. Some Practical Aspects of Sugar Fermentation by Baker's Yeast (Saccharomyces cerevisiae)

    Science.gov (United States)

    Freeland, P. W.

    1973-01-01

    Describes simple quantitative determinations for ethanol and carbon dioxide, together with techniques for examining the effects of a number of environmental factors on their production. The experimental work centers around the growth of a cell population of yeast, and is suitable for senior high school students. (JR)

  12. Effect of nitrogen and phosphate on the levels of intermediates in bakers' yeast grown in continuous culture

    Energy Technology Data Exchange (ETDEWEB)

    Franco, C.M.M.; Smith, J.E.; Berry, D.R.

    1984-01-01

    Bakers' yeast (Saccharomyces cerevisiae) was grown in continuous culture using a control medium and media which contained low levels of NH4 and phosphate. The effects of medium composition and growth rate on the levels of intermediates of the glycolytic pathways, the tricarboxylic acid cycle, and the glyoxylate cycle were investigated. The energy charge varied only between 0.7 and 0.9 over the range of dilution rates studied; however, the level of ATP decreased by 50% at higher aerobic growth rates. Intermediates of the Embden-Meyerhoff-Parnas pathway were higher at the low aerobic growth rates and decreased as the dilution rate was increased. However, higher levels of these intermediates were also observed at even higher dilution rates at which EtOH formation and fermentative metabolism occurred. Significant differences in levels of intermediates were observed between control experiments and fermentations using the low N and phosphate media. The greatest differences were observed in the levels of glucose 6-phosphate, 6-phosphogluconate, pyruvate, citrate and glyoxlate. Twenty-one different steady states were investigated and each had a unique composition.

  13. Genetic analysis of baker's yeast Msh4-Msh5 reveals a threshold crossover level for meiotic viability.

    Directory of Open Access Journals (Sweden)

    K T Nishant

    2010-08-01

    Full Text Available During meiosis, the Msh4-Msh5 complex is thought to stabilize single-end invasion intermediates that form during early stages of recombination and subsequently bind to Holliday junctions to facilitate crossover formation. To analyze Msh4-Msh5 function, we mutagenized 57 residues in Saccharomyces cerevisiae Msh4 and Msh5 that are either conserved across all Msh4/5 family members or are specific to Msh4 and Msh5. The Msh5 subunit appeared more sensitive to mutagenesis. We identified msh4 and msh5 threshold (msh4/5-t mutants that showed wild-type spore viability and crossover interference but displayed, compared to wild-type, up to a two-fold decrease in crossing over on large and medium sized chromosomes (XV, VII, VIII. Crossing over on a small chromosome, however, approached wild-type levels. The msh4/5-t mutants also displayed synaptonemal complex assembly defects. A triple mutant containing a msh4/5-t allele and mutations that decreased meiotic double-strand break levels (spo11-HA and crossover interference (pch2Δ showed synergistic defects in spore viability. Together these results indicate that the baker's yeast meiotic cell does not require the ∼90 crossovers maintained by crossover homeostasis to form viable spores. They also show that Pch2-mediated crossover interference is important to maintain meiotic viability when crossovers become limiting.

  14. The pch2Delta mutation in baker's yeast alters meiotic crossover levels and confers a defect in crossover interference.

    Directory of Open Access Journals (Sweden)

    Sarah Zanders

    2009-07-01

    Full Text Available Pch2 is a widely conserved protein that is required in baker's yeast for the organization of meiotic chromosome axes into specific domains. We provide four lines of evidence suggesting that it regulates the formation and distribution of crossover events required to promote chromosome segregation at Meiosis I. First, pch2Delta mutants display wild-type crossover levels on a small (III chromosome, but increased levels on larger (VII, VIII, XV chromosomes. Second, pch2Delta mutants show defects in crossover interference. Third, crossovers observed in pch2Delta require both Msh4-Msh5 and Mms4-Mus81 functions. Lastly, the pch2Delta mutation decreases spore viability and disrupts crossover interference in spo11 hypomorph strains that have reduced levels of meiosis-induced double-strand breaks. Based on these and previous observations, we propose a model in which Pch2 functions at an early step in crossover control to ensure that every homolog pair receives an obligate crossover.

  15. Baker's Yeast Deficient in Storage Lipid Synthesis Uses cis-Vaccenic Acid to Reduce Unsaturated Fatty Acid Toxicity.

    Science.gov (United States)

    Sec, Peter; Garaiova, Martina; Gajdos, Peter; Certik, Milan; Griac, Peter; Hapala, Ivan; Holic, Roman

    2015-07-01

    The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.

  16. Teaching microbial physiology using glucose repression phenomenon in baker's yeast as an examplele

    DEFF Research Database (Denmark)

    Vijayendran, Raghavendran; Nielsen, Jens; Olsson, Lisbeth

    2005-01-01

    The yeast Saccharomyces cerevisiae has been used by human beings since ancient times for its ability to convert sugar to alcohol. Continual exposure to glucose in the natural environment for innumerable generations has probably enabled S. cerevisiae to grow in fermentative mode on sugars by switc......The yeast Saccharomyces cerevisiae has been used by human beings since ancient times for its ability to convert sugar to alcohol. Continual exposure to glucose in the natural environment for innumerable generations has probably enabled S. cerevisiae to grow in fermentative mode on sugars...... by switching off the genes responsible for respiration even under aerobic conditions. This phenomenon is referred to as the Crabtree effect. The present review focuses on glucose repression in S. cerevisiae from a physiological perspective. Physiological studies presented involve batch and chemostat...

  17. Effect of sodium chloride on bakers' yeast growing in gelatin

    Energy Technology Data Exchange (ETDEWEB)

    Wei, C.J.; Tanner, R.D.; Malaney, G.W.

    1982-04-01

    In recent years, industrial fermentation researchers have shifted their attention from liquid to solid and semisolid culture conditions. We converted liquid cultures to the semisolid mode by adding high levels of gelatin. Previous studies on liquid cultures have revealed the inhibitory activity of mineral salts, such as NaCl, on the fermentation of sugars by yeasts. We made a kinetic study of the effects of 1 to 5% (wt/vol) NaCl on the alcoholic fermentations of glucose by Saccharomyces cerevisiae in a growth medium containing 16% gelatin. Our results showed that the effect of high salt content on semisolid culture is essentially the same as the effect on liquid culture; i.e., as the salt content increased, the following occurred: (i) the growth of yeasts decreased, (ii) the lag period of the yeast biomass curve lengthened, (iii) the sugar intake was lowered, (iv) the yield of ethanol was reduced and (v) the production of glycerol was increased. We observed a new relationship correlating the area of kinetic hysteresis with ethanol production rate, acetaldehyde concentration, and the initial NaCl concentration. (Refs. 20).

  18. Effects of dietary live and heat-inactive baker's yeast on growth, gut health, and disease resistance of Nile tilapia under high rearing density.

    Science.gov (United States)

    Ran, Chao; Huang, Lu; Hu, Jun; Tacon, Philippe; He, Suxu; Li, Zhimin; Wang, Yibing; Liu, Zhi; Xu, Li; Yang, Yalin; Zhou, Zhigang

    2016-09-01

    In this study, the effects of baker's yeast as probiotics was evaluated in Nile tilapia reared at high density. Juvenile tilapia were distributed to tanks at high density (436 fish/m(3)) and fed with basal diet (CK) or diets supplemented with live (LY) or heat-inactivated yeast (HIY). Another group of fish reared at low density (218 fish/m(3)) and fed with basal diet was also included (LowCK). After 8 weeks of feeding, growth, feed utilization, gut microvilli morphology, digestive enzymes, and expressions of hsp70 and inflammation-related cytokines in the intestine were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Fish were challenged with Aeromonas hydrophila to evaluate disease resistance. High rearing density significantly decreased the growth, feed utilization, microvilli length, and disease resistance of fish (CK versus LowCK). Moreover, the intestinal hsp70 expression was increased in fish reared at high density, supporting a stress condition. Compared to CK group, supplementation of live yeast significantly increased gut microvilli length and trypsin activity, decreased intestinal hsp70 expression, and enhanced resistance of fish against A. hydrophila (reflected by reduced intestinal alkaline phosphatase activity 24 h post infection). The gut microbiota was not markedly influenced by either rearing density or yeast supplementation. Heat-inactivated yeast (HIY) didn't display the beneficial effects observed in LY except an increase in gut trypsin activity, suggesting the importance of yeast viability and thus secretory metabolites of yeast. In conclusion, live baker's yeast may alleviate the negative effects induced by crowding stress, and has the potential to be used as probiotics for tilapia reared at high density.

  19. Molecular Cloning and Yeast Expression of Cinnamate 4-Hydroxylase from Ornithogalum saundersiae Baker

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    Jian-Qiang Kong

    2014-01-01

    Full Text Available OSW-1, isolated from the bulbs of Ornithogalum saundersiae Baker, is a steroidal saponin endowed with considerable antitumor properties. Biosynthesis of the 4-methoxybenzoyl group on the disaccharide moiety of OSW-1 is known to take place biochemically via the phenylpropanoid biosynthetic pathway, but molecular biological characterization of the related genes has been insufficient. Cinnamic acid 4-hydroxylase (C4H, EC 1.14.13.11, catalyzing the hydroxylation of trans-cinnamic acid to p-coumaric acid, plays a key role in the ability of phenylpropanoid metabolism to channel carbon to produce the 4-methoxybenzoyl group on the disaccharide moiety of OSW-1. Molecular isolation and functional characterization of the C4H genes, therefore, is an important step for pathway characterization of 4-methoxybenzoyl group biosynthesis. In this study, a gene coding for C4H, designated as OsaC4H, was isolated according to the transcriptome sequencing results of Ornithogalum saundersiae. The full-length OsaC4H cDNA is 1,608-bp long, with a 1,518-bp open reading frame encoding a protein of 505 amino acids, a 55-bp 5′ non-coding region and a 35-bp 3'-untranslated region. OsaC4H was functionally characterized by expression in Saccharomyces cerevisiae and shown to catalyze the oxidation of trans-cinnamic acid to p-coumaric acid, which was identified by high performance liquid chromatography with diode array detection (HPLC-DAD, HPLC-MS and nuclear magnetic resonance (NMR analysis. The identification of the OsaC4H gene was expected to open the way to clarification of the biosynthetic pathway of OSW-1.

  20. Preconcentrating (within the broth) secreted extracellular proteins during a bakers' yeast fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Effler, W.T. Jr.; Pandey, N.K.; Tanner, R.D.; Malaney, G.W.; Scott, C.D. (ed.)

    1986-01-01

    Proteins secreted by yeast during the fermentation process are spacially fractionated (concentrated at a particular vertical position) within the fermentation vessel due to the phenomenon of bubble fractionation, despite moderately vigorous mixing. The degree of fractionation is influenced by the conditions in which the fermentation takes place. The broth pH strongly influences the extent of fractionation of specific proteins. In addition fractionation is enhanced under anaerobic conditions, presumably because there are more CO2 bubbles present for hydrophobic protein adsorption. The addition of moderate levels of salt to the broth reduces the fractionation for most (but not all) of the proteins.

  1. Self-tuning GMV control of glucose concentration in fed-batch baker's yeast production.

    Science.gov (United States)

    Hitit, Zeynep Yilmazer; Boyacioglu, Havva; Ozyurt, Baran; Ertunc, Suna; Hapoglu, Hale; Akay, Bulent

    2014-04-01

    A detailed system identification procedure and self-tuning generalized minimum variance (STGMV) control of glucose concentration during the aerobic fed-batch yeast growth were realized. In order to determine the best values of the forgetting factor (λ), initial value of the covariance matrix (α), and order of the Auto-Regressive Moving Average with eXogenous (ARMAX) model (n a, n b), transient response data obtained from the real process wereutilized. Glucose flow rate was adjusted according to the STGMV control algorithm coded in Visual Basic in an online computer connected to the system. Conventional PID algorithm was also implemented for the control of the glucose concentration in aerobic fed-batch yeast cultivation. Controller performances were examined by evaluating the integrals of squared errors (ISEs) at constant and random set point profiles. Also, batch cultivation was performed, and microorganism concentration at the end of the batch run was compared with the fed-batch cultivation case. From the system identification step, the best parameter estimation was accomplished with the values λ = 0.9, α = 1,000 and n a = 3, n b = 2. Theoretical control studies show that the STGMV control system was successful at both constant and random glucose concentration set profiles. In addition, random effects given to the set point, STGMV control algorithm were performed successfully in experimental study.

  2. Baker's yeast catalyzed asymmetric reduction of prochiral ketones in different reaction mediums

    Directory of Open Access Journals (Sweden)

    Adi Wolfson

    2013-03-01

    Full Text Available Baker’s yeast catalyzes the asymmetric reduction of prochiral ketones in water and in various organic solvents. The reaction in water, which is the first solvent of choice for bio-reactions, led to a high product yield and enantiomeric excess, but the low miscibility of organic molecules in water resulted in lower conversions when more hydrophobic ketones were used. Petroleum-based solvents such as hexane and petroleum ether were also successfully employed as reaction mediums, but the viability of the yeast in these solvents was negligible, and they have severe environmental impacts due to their high toxicity levels. Performing the reaction in green solvents, like ionic liquids, fluorous media, and glycerol-based solvents, which have low volatilities and can be recycled, enabled dissolution of the substrates and of the energy source and also promoted isolation of the product. Among all tested green solvents, glycerol-based solvents are preferable due to their biodegradable natures and their origins from renewable sources.

  3. Influence of addition of amylase preparation to dough on fermentative activity of baker's yeast

    Directory of Open Access Journals (Sweden)

    Dodić Jelena M.

    2005-01-01

    Full Text Available Dough samples with different content of amylases were investigated immediately after mixing and after 7, 14 and 30 days of frozen storage. The obtained results show that the fermentation time is shorter, both in fresh and frozen samples, when amylase sample 1 was added, compared to dough without enzymes. The addition of amylase 2 to dough resulted in minimal decrease of "rising" time, both is frozen and fresh dough samples. The rising time of fresh samples was shorter when amylase 3 was added to dough. The specific fermentative activity of fresh dough samples is increasing by about 10% compared to the control sample, for all amounts of amylase 1 and 2 added to the do- ugh. The fermentative activity of yeast in frozen samples increased by 5-10%, after keeping of dough with the addition of amylase 1 for 14 days. The specific fermentative activity of fresh dough samples increased compared to the control, for all amounts of added amylase 3 to the dough. In frozen dough samples the fermentative activity of yeast decreased by 10% for all added amounts of amylase 3. Baked goods made of fresh and frozen dough, prepared with the addition of amylase 1, are better than the ones made of control dough sample, considering all evaluated parameters.

  4. Identification and dissection of a complex DNA repair sensitivity phenotype in Baker's yeast.

    Directory of Open Access Journals (Sweden)

    Ann Demogines

    2008-07-01

    Full Text Available Complex traits typically involve the contribution of multiple gene variants. In this study, we took advantage of a high-density genotyping analysis of the BY (S288c and RM strains of Saccharomyces cerevisiae and of 123 derived spore progeny to identify the genetic loci that underlie a complex DNA repair sensitivity phenotype. This was accomplished by screening hybrid yeast progeny for sensitivity to a variety of DNA damaging agents. Both the BY and RM strains are resistant to the ultraviolet light-mimetic agent 4-nitroquinoline 1-oxide (4-NQO; however, hybrid progeny from a BYxRM cross displayed varying sensitivities to the drug. We mapped a major quantitative trait locus (QTL, RAD5, and identified the exact polymorphism within this locus responsible for 4-NQO sensitivity. By using a backcrossing strategy along with array-assisted bulk segregant analysis, we identified one other locus, MKT1, and a QTL on Chromosome VII that also link to the hybrid 4-NQO-sensitive phenotype but confer more minor effects. This work suggests an additive model for sensitivity to 4-NQO and provides a strategy for mapping both major and minor QTL that confer background-specific phenotypes. It also provides tools for understanding the effect of genetic background on sensitivity to genotoxic agents.

  5. Inactivation of Bakers' yeast glucose-6-phosphate dehydrogenase by aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sungwoo; Joshi, J.G. (Univ. of Tennessee, Knoxville (USA))

    1989-04-18

    Preincubation of yeast glucose-6-phosphate dehydrogenase (G6PD) with Al(III) produced an inactive enzyme containing 1 mol of Al(III)/mol of enzyme subunit. None of the enzyme-bound Al(III) was dissociated by dialysis against 10 mM Tris-HCl, pH 7.0, containing 0.2 mM EDTA at 4{degree}C for 24 h. Citrate, NADP{sup +}, EDTA, or NaF protected the enzyme against the Al(III) inactivation. The Al(III)-inactivated enzyme, however, was completely reactivated only by citrate and NaF. The dissociation constant for the enzyme-aluminum complex was calculated to be 4 {times} 10{sup {minus}6} M with NaF, a known reversible chelator for aluminum. Modification of histidine and lysine residues of the enzyme with diethyl pyrocarbonate and acetylsalicylic acid, respectively, inactivated the enzyme. However, the modified enzyme still bound 1 mol of Al(III)/mol of enzyme subunit. Circular dichroism studies showed that the binding of Al(III) to the enzyme induced a decrease in {alpha}-helix and {beta}-sheet and an increase in random coil. Therefore, it is suggested that inactivation of G6PD by Al(III) is due to the conformational change induced by Al(III) binding.

  6. [Constructing recombinant plasmid pSH-CUP and knockout of acid trehalase gene in baker's yeast].

    Science.gov (United States)

    He, Dongqin; Xiao, Dongguang; Lv, Ye

    2008-02-01

    The ATH1 gene encoded acid trehalase in Saccharomyces cerevisiae. The gene disruption cassette combined the heterologous dominant kan(r) resistance marker with a Cre/loxP-mediated marker removal procedure. The gene disruption cassette was produced by PCR using the same long oligonucleotides comprising 50 nucleotides that annealed to sites upstream or downstream of the genomic target sequence to be deleted. After transformation of the linear disruption cassettes with a Cre/loxP-mediated marker into the cells of Saccharomyces cerevisiae BY-6, selected transformants were checked by PCR for correct the integration of the cassette and concurrent deletion of the chromosomal target sequence. The copper-resistance gene (CUP1-MT1) was cloned into pSH47, which yielded pSH-CUP. The recombinant plasmid pSH-CUP was transformed into the cells of Saccharomyces cerevisiae BY-6(delta ATH1, G418(r)), and transformants were selected for copper resistance. Upon expression of the Cre recombinase results in removal of the kan(r) gene, leaving behind a single loxP site at the chromosomal locus. Construction of the recombinant plasmid pSH-CUP avoided inserting non-yeast gene and made the loxP - kanMX - loxP gene disruption cassette more conventional for eukaryotic organism gene disruption.

  7. The baker's yeast diploid genome is remarkably stable in vegetative growth and meiosis.

    Directory of Open Access Journals (Sweden)

    K T Nishant

    2010-09-01

    Full Text Available Accurate estimates of mutation rates provide critical information to analyze genome evolution and organism fitness. We used whole-genome DNA sequencing, pulse-field gel electrophoresis, and comparative genome hybridization to determine mutation rates in diploid vegetative and meiotic mutation accumulation lines of Saccharomyces cerevisiae. The vegetative lines underwent only mitotic divisions while the meiotic lines underwent a meiotic cycle every ∼20 vegetative divisions. Similar base substitution rates were estimated for both lines. Given our experimental design, these measures indicated that the meiotic mutation rate is within the range of being equal to zero to being 55-fold higher than the vegetative rate. Mutations detected in vegetative lines were all heterozygous while those in meiotic lines were homozygous. A quantitative analysis of intra-tetrad mating events in the meiotic lines showed that inter-spore mating is primarily responsible for rapidly fixing mutations to homozygosity as well as for removing mutations. We did not observe 1-2 nt insertion/deletion (in-del mutations in any of the sequenced lines and only one structural variant in a non-telomeric location was found. However, a large number of structural variations in subtelomeric sequences were seen in both vegetative and meiotic lines that did not affect viability. Our results indicate that the diploid yeast nuclear genome is remarkably stable during the vegetative and meiotic cell cycles and support the hypothesis that peripheral regions of chromosomes are more dynamic than gene-rich central sections where structural rearrangements could be deleterious. This work also provides an improved estimate for the mutational load carried by diploid organisms.

  8. Expression of LIP1 and LIP2 genes from Geotrichum species in Baker's yeast strains and their application to the bread-making process.

    Science.gov (United States)

    Monfort, A; Blasco, A; Sanz, P; Prieto, J A

    1999-02-01

    Lipolytic baker's yeast strains able to produce extracellular active lipase have been constructed by transformation with plasmids containing the LIP1 and LIP2 genes from Geotrichum sp. under the control of the Saccharomyces cerevisiae actin promoter (pACT1). Lipase productivity differed between both constructs, YEpACT-LIP1-t and YEpACT-LIP2-t, being higher for the strain bearing the LIP2 gene in all culture media tested. This result appeared not to be the consequence of a defect in the transcription of the LIP1 gene as revealed by Northern blot analysis. Replacing the signal sequence of LIP1 by that of LIP2 in the YEpACT-LIP1-t plasmid enhanced significantly the secretion of lipase 1, but the levels of lipase activity were still lower than those found for the YEpACT-LIP2-t transformant. Recombinant lipase 2 protein produced by baker's yeast exhibited biochemical properties similar to those of the natural enzyme. Fermented dough prepared with YEpACT-LIP2-t-carrying cells rendered a bread with a higher loaf volume and a more uniform crumb structure than that prepared with control yeast. These effects were stronger by the addition in the bread dough formulas of a preferment enriched in recombinant lipase 2.

  9. Enhanced freeze tolerance of baker's yeast by overexpressed trehalose-6-phosphate synthase gene (TPS1) and deleted trehalase genes in frozen dough.

    Science.gov (United States)

    Tan, Haigang; Dong, Jian; Wang, Guanglu; Xu, Haiyan; Zhang, Cuiying; Xiao, Dongguang

    2014-08-01

    Several recombinant strains with overexpressed trehalose-6-phosphate synthase gene (TPS1) and/or deleted trehalase genes were obtained to elucidate the relationships between TPS1, trehalase genes, content of intracellular trehalose and freeze tolerance of baker's yeast, as well as improve the fermentation properties of lean dough after freezing. In this study, strain TL301(TPS1) overexpressing TPS1 showed 62.92 % higher trehalose-6-phosphate synthase (Tps1) activity and enhanced the content of intracellular trehalose than the parental strain. Deleting ATH1 exerted a significant effect on trehalase activities and the degradation amount of intracellular trehalose during the first 30 min of prefermentation. This finding indicates that acid trehalase (Ath1) plays a role in intracellular trehalose degradation. NTH2 encodes a functional neutral trehalase (Nth2) that was significantly involved in intracellular trehalose degradation in the absence of the NTH1 and/or ATH1 gene. The survival ratio, freeze-tolerance ratio and relative fermentation ability of strain TL301(TPS1) were approximately twice as high as those of the parental strain (BY6-9α). The increase in freeze tolerance of strain TL301(TPS1) was accompanied by relatively low trehalase activity, high Tps1 activity and high residual content of intracellular trehalose. Our results suggest that overexpressing TPS1 and deleting trehalase genes are sufficient to improve the freeze tolerance of baker's yeast in frozen dough. The present study provides guidance for the commercial baking industry as well as the research on the intracellular trehalose mobilization and freeze tolerance of baker's yeast.

  10. Covalent aspartylation of aspartyl-tRNA synthetase from Bakers' yeast by its cognat aspartyl adenylate: identification of the labeled residues

    Energy Technology Data Exchange (ETDEWEB)

    Mejdoub, H.; Kern, D.; Giege, R.; Ebel, J.P.; Boulanger, Y.; Reinbolt, J.

    1987-04-07

    Aspartyl-tRNA synthetase from bakers' yeast gives an unstable complex with the cognate adenylate, which reacts after dissociation with amino acid side chains of the protein. This leads to a covalent incorporation of (/sup 14/C)-aspartic acid into aspartyl-tRNA synthetase via amide or ester bonds formed between the ..cap alpha..-carboxyl group of activated aspartic acid and accessible lysines, serines, and threonines. This property is used to label the peptides at the surface of the enzyme. The main labeled residues have been identified, and their location in the primary structure is discussed in relation to structural properties of aspartyl-tRNA synthetase.

  11. O emprego de fermento de pão, Saccharomyces cerevisiae, na síntese de feromônios Baker's yeast, Saccharomyces cerevisiae, as a tool for the synthesis of pheromones

    Directory of Open Access Journals (Sweden)

    Patrícia T. Baraldi

    2004-06-01

    Full Text Available The use of pheromones in integrated pest management has been increasing in the last years due to environmental concern. This development is accompanied by the search for simple, efficient and less aggressive synthetic methodologies for the preparation of pheromones. One of these methodologies includes microbiological reactions, more specifically biocatalytic reduction of carbonyl compounds using baker's yeast (Saccharomyces cerevisiae. This review presents the use of baker's yeast as an easy and cheap alternative to obtain enantiomerically enriched compounds employed in the synthesis of pheromones.

  12. Heterologous expression of type I antifreeze peptide GS-5 in baker's yeast increases freeze tolerance and provides enhanced gas production in frozen dough.

    Science.gov (United States)

    Panadero, Joaquin; Randez-Gil, Francisca; Prieto, Jose Antonio

    2005-12-28

    The demand for frozen-dough products has increased notably in the baking industry. Nowadays, no appropriate industrial baker's yeast with optimal gassing capacity in frozen dough is, however, available, and it is unlikely that classical breeding programs could provide significant improvements of this trait. Antifreeze proteins, found in diverse organisms, display the ability to inhibit the growth of ice, allowing them to survive at temperatures below 0 degrees C. In this study a recombinant antifreeze peptide GS-5 was expressed from the polar fish grubby sculpin (Myoxocephalus aenaeus) in laboratory and industrial baker's yeast strains of Saccharomyces cerevisiae. Production of the recombinant protein increased freezing tolerance in both strains tested. Furthermore, expression of the GS-5 encoding gene enhanced notably the gassing rate and total gas production in frozen and frozen sweet doughs. These effects are unlikely to be due to reduced osmotic damage during freezing/thawing, because recombinant cells showed growth behavior similar to that of the parent under hypermosmotic stress conditions.

  13. Facile one-pot fabrication of nano-Fe3O4/carboxyl-functionalized baker's yeast composites and their application in methylene blue dye adsorption

    Science.gov (United States)

    Du, Zongjun; Zhang, Yue; Li, Zhengjie; Chen, Hui; Wang, Ying; Wang, Guangtu; Zou, Ping; Chen, Huaping; Zhang, Yunsong

    2017-01-01

    Nano-Fe3O4/carboxyl-functionalized baker's yeast composites (NF/CF-BYs) were prepared for the first time based on the ultrasonic cavitation assisted oxygen implosion method using single Fe2+ as iron source. The series of characterization analysis results showed that the obtained NF/CF-BYs had not only the superparamagnetic properties of nano-Fe3O4, but their surface also had plenty of functional groups (especially carboxyl groups) introduced by strong oxidization. The adsorption properties of NF/CF-BYs for methylene blue (MB) were also evaluated. The results displayed that the uptakes of NF/CF-BYs for MB were higher than that of pristine baker's yeast (P-BYs), and the adsorption process was followed by the pseudo-second-order kinetic model and Langmuir isotherm. The maximum adsorption capacity of NF/CF-BYs for MB was estimated to be 141.75 mg g-1 at pH 6. The regeneration efficiency of the obtained NF/CF-BYs was attained to be more than 90%.

  14. 利用枣汁生产面包酵母%Production of Baker's Yeast Using Date Juice

    Institute of Scientific and Technical Information of China (English)

    A.; Beiroti; S.; N.; Hosseini

    2007-01-01

    Baker's yeast is an important additive among the products which improves bread quality and for present time is being produced in different countries by batch,fed batch or continuous cultures.Saccharomyces cerevisiae is used in fermentation of starch in dough,giving a favourable taste and produces a variety of vitamins and proteins.The main ingredient in yeast production is carbon source such as beet molasses,cane molasses,and so on.Since beet molasses has other major function as in high yield alcohol production and also due to the bioenvironmental issues and related wastewater treatment,the use of other carbohydrate sources may be considered.One of these carbohydrate sources is date which is wasted a great deal annually in this country (Iran).In this study,the capability of date to act as a suitable carbon sources was investigated.The waste date turned into juice and consequently production and growth rate of Sacchromyces cervisiae were studied with this juice.A maximum possible yield of 50% was obtained by the optimum medium (P3),at pH 3.4,30°C,1.4vvm aeration mte and agitation of 500r/min.%面包酵母是一类用来提高面包质量的重要添加荆.目前,不同国家主要采用分批培养、补料分批培养或连续培养的方式来生产面包酵母.酿酒酵母是用来发酵面团中淀粉的理想微生物,除了提升食品香味,增加口感之外,这一发酵过程可以产生多种维生素和蛋白质.用于生产酵母生物量的主要成分包括各种碳源,如甜菜糖蜜和甘蔗糖蛮等.由于甜菜糖蜜可用于高产率地生产乙醇,加之其带来的生物环境污染和废水处理问题,因此需要考虑用其他糖类来生产面包酵母.其中一个代替性糖源是枣.由于各种原因,伊朗每年都浪费大量的枣.研究了用枣作为培养基碳源的可行性.将废枣榨成汁,然后研究了酵母的产量和生长速率.结果发现,在pH3.4,温度30℃,通风量1.4wm,发酵罐搅拌速度500r/min时,

  15. Baker cyst

    Science.gov (United States)

    Popliteal cyst; Bulge-knee ... A Baker cyst is caused by swelling in the knee. The swelling is due to an increase in the fluid that ... squeezes into the back of the knee. Baker cyst commonly occurs with: A tear in the meniscal ...

  16. Thiamine increases the resistance of baker's yeast Saccharomyces cerevisiae against oxidative, osmotic and thermal stress, through mechanisms partly independent of thiamine diphosphate-bound enzymes.

    Science.gov (United States)

    Wolak, Natalia; Kowalska, Ewa; Kozik, Andrzej; Rapala-Kozik, Maria

    2014-12-01

    Numerous recent studies have established a hypothesis that thiamine (vitamin B1 ) is involved in the responses of different organisms against stress, also suggesting that underlying mechanisms are not limited to the universal role of thiamine diphosphate (TDP) in the central cellular metabolism. The current work aimed at characterising the effect of exogenously added thiamine on the response of baker's yeast Saccharomyces cerevisiae to the oxidative (1 mM H2 O2 ), osmotic (1 M sorbitol) and thermal (42 °C) stress. As compared to the yeast culture in thiamine-free medium, in the presence of 1.4 μM external thiamine, (1) the relative mRNA levels of major TDP-dependent enzymes under stress conditions vs. unstressed control (the 'stress/control ratio') were moderately lower, (2) the stress/control ratio was strongly decreased for the transcript levels of several stress markers localised to the cytoplasm, peroxisomes, the cell wall and (with the strongest effect observed) the mitochondria (e.g. Mn-superoxide dismutase), (3) the production of reactive oxygen and nitrogen species under stress conditions was markedly decreased, with the significant alleviation of concomitant protein oxidation. The results obtained suggest the involvement of thiamine in the maintenance of redox balance in yeast cells under oxidative stress conditions, partly independent of the functions of TDP-dependent enzymes.

  17. Isolation and Screening of Haploid of Baker's Yeast with High Sugar Tolerance%耐高糖面包酵母单倍体的分离筛选

    Institute of Scientific and Technical Information of China (English)

    封冰; 张翠英; 肖冬光

    2014-01-01

    Spore-producing culture of baker's yeast BY-6 with high sugar tolerance was carried out to obtain its haploids. 6 strains of type alpha haploid and 5 strains of type a haploid were separated and identified by matching and PCR authentication. Compared with the parental strain, a-70 strain andα-24 strain were obtained based on their excellent performance in biomass, growth curve, fermentation ability in high-sugar dough, and gas production in the simulation of high-sugar dough. This study laid a good foundation for genetic breeding of baker's yeast with high sugar toler-ance in the future.%以耐高糖面包酵母BY-6为出发菌株进行生孢培养制备单倍体,通过单倍体的分离、配型验证和PCR验证,获得6株α型单倍体,5株a型单倍体。通过比较单倍体菌株的生长和发酵性能,筛选出生长性能较好,在高糖模拟面团中产气量较大,并且在高糖面团中发酵力较高的优良单倍体菌株70a和24α,这为后续通过基因工程改造提高面包酵母的高糖耐性奠定了良好的基础。

  18. Asymmetric bioreduction of acetophenones by Baker's yeast and its cell-free extract encapsulated in sol–gel silica materials

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Katsuya, E-mail: katsuya-kato@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya, 463-8560 (Japan); Nakamura, Hitomi [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya, 463-8560 (Japan); Nakanishi, Kazuma [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie, 514-8570 (Japan)

    2014-02-28

    Baker's yeast (BY) encapsulated in silica materials was synthesized using a yeast cell suspension and its cell-free extract during a sol–gel reaction of tetramethoxysilane with nitric acid as a catalyst. The synthesized samples were fully characterized using various methods, such as scanning electron microscopy, nitrogen adsorption–desorption, Fourier transform infrared spectroscopy, thermogravimetry, and differential thermal analysis. The BY cells were easily encapsulated inside silica-gel networks, and the ratio of the cells in the silica gel was approximately 75 wt%, which indicated that a large volume of BY was trapped with a small amount of silica. The enzyme activity (asymmetric reduction of prochiral ketones) of BY and its cell-free extract encapsulated in silica gel was investigated in detail. The activities and enantioselectivities of free and encapsulated BY were similar to those of acetophenone and its fluorine derivatives, which indicated that the conformation structure of BY enzymes inside silica-gel networks did not change. In addition, the encapsulated BY exhibited considerably better solvent (methanol) stability and recyclability compared to free BY solution. We expect that the development of BY encapsulated in sol–gel silica materials will significantly impact the industrial-scale advancement of high-efficiency and low-cost biocatalysts for the synthesis of valuable chiral alcohols.

  19. Recombinant Expression and Phenotypic Screening of a Bioactive Cyclotide Against α-Synuclein-Induced Cytotoxicity in Baker's Yeast.

    Science.gov (United States)

    Jagadish, Krishnappa; Gould, Andrew; Borra, Radhika; Majumder, Subhabrata; Mushtaq, Zahid; Shekhtman, Alexander; Camarero, Julio A

    2015-07-13

    We report for the first time the recombinant expression of fully folded bioactive cyclotides inside live yeast cells by using intracellular protein trans-splicing in combination with a highly efficient split-intein. This approach was successfully used to produce the naturally occurring cyclotide MCoTI-I and the engineered bioactive cyclotide MCoCP4. Cyclotide MCoCP4 was shown to reduce the toxicity of human α-synuclein in live yeast cells. Cyclotide MCoCP4 was selected by phenotypic screening from cells transformed with a mixture of plasmids encoding MCoCP4 and inactive cyclotide MCoTI-I in a ratio of 1:5×10(4). This demonstrates the potential for using yeast to perform phenotypic screening of genetically encoded cyclotide-based libraries in eukaryotic cells.

  20. Stable high-copy-number integration of Aspergillus oryzae alpha-AMYLASE cDNA in an industrial baker's yeast strain.

    Science.gov (United States)

    Nieto, A; Prieto, J A; Sanz, P

    1999-01-01

    The Aspergillus oryzae alpha-amylase cDNA was placed under the control of the Saccharomyces cerevisiae actin promoter (pACT1) and introduced into the ribosomal DNA locus of an industrial baker's yeast strain. To obtain a strain eligible for commercial use, we constructed an integrative cassette lacking bacterial DNA sequences but containing the alpha-amylase cDNA and ribosomal DNA sequences to target the integration to this locus. High-copy-number integrants were obtained including a defective TRP1d promoter in the integrative cassette. We selected one transformant, Rib-AMY (CECT10872), in which the multi-integrated sequences were stable even after 200 generations of growth in nonselective medium. This transformant also expressed and secreted high levels of alpha-amylase. Bread made with this strain had a higher volume, lower density, and softer crumbs than bread made with a control strain. The Rib-AMY transformant also was useful in retarding bread firming. This new strain fulfills all the requirements for commercial utilization and should reduce or eliminate the requirement for addition of exogenous alpha-amylase to the flour, reducing allergenic work-related symptoms due to this enzyme.

  1. Increased availability of NADH in metabolically engineered baker's yeast improves transaminase-oxidoreductase coupled asymmetric whole-cell bioconversion

    DEFF Research Database (Denmark)

    Knudsen, Jenny Dahl; Hägglöf, Cecilia; Weber, Nora

    2016-01-01

    yeast for transamination-reduction coupled asymmetric one-pot conversion was investigated. RESULTS: A series of active whole-cell biocatalysts were constructed by over-expressing the (S)-selective ω-transaminase (VAMT) from Capsicum chinense together with the NADH-dependent (S)-selective alcohol...... dehydrogenase (SADH) originating from Rhodococcus erythropolis in strains with or without deletion of glycerol-3-phosphate dehydrogenases 1 and 2 (GPD1 and GPD2). The yeast strains were evaluated as catalysts for simultaneous: (a) kinetic resolution of the racemic mixture to (R)-1-phenylethylamine, and (b......) reduction of the produced acetophenone to (S)-1-phenylethanol. For the gpd1Δgpd2Δ strain, cell metabolism was effectively used for the supply of both amine acceptors and the co-factor pyridoxal-5'-phosphate (PLP) for the ω-transaminase, as well as for regenerating NADH for the reduction. In contrast...

  2. Cytoplasmic methionyl-tRNA synthetase from Bakers' yeast. A monomer with a post-translationally modified N terminus.

    Science.gov (United States)

    Fasiolo, F; Gibson, B W; Walter, P; Chatton, B; Biemann, K; Boulanger, Y

    1985-12-15

    Methionyl-tRNA synthetase has been purified from a yeast strain carrying the MES1 structural gene on a high copy number plasmid (pFL1). The purified enzyme is a monomer of Mr = 85,000 in contrast to its counterpart from Escherichia coli which is a dimer made up of identical subunits (Mr = 76,000; Dardel, F., Fayat, G., and Blanquet, S. (1984) J. Bacteriol. 160, 1115-1122). The yeast enzyme was not amenable to Edman's degradation indicating a blocked NH2 terminus. Its primary structure as derived from the DNA sequence (Walter, P., Gangloff, J., Bonnet, J., Boulanger, Y., Ebel, J.P., and Fasiolo, F. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 2437-2441) has been confirmed using the fast atom bombardment-mass spectrometric method. This method was applied to tryptic digests of the carboxymethylated enzyme and the corresponding data provided extensive coverage of the translated DNA sequence, thus confirming its correctness. The ambiguity concerning which of the three NH2-terminally located methionine codons is the initiation codon was easily resolved from peptides identified in this region. It was possible to show that the first methionine had been removed and that the new NH2 terminus, serine, had been acetylated. A comparison between the yeast and E. coli sequences shows that the former has an N-terminal extension of about 200 residues as compared to the latter. It also lacks the C-terminal domain which is responsible for the dimerization of the E. coli methionyl-tRNA synthetase.

  3. Measurement of the gassing power of bakers' yeast: correlation between the dough volume and the incubation time

    Directory of Open Access Journals (Sweden)

    Walter Borzani

    2004-06-01

    Full Text Available An empirical equation is proposed to correlate the dough volume and the incubation time during cylinder tests using thin flour dough carried out to evaluate the gassing power of compressed yeast. The above equation permitted to correlate the gassing power of the yeast and the proof time, as well as to calculate the specific rate of the dough volume variation at any time. It provided more information regarding the fermentation power of the yeast than the sole value of its gas-producing power. A physical interpretation of the proposed equation is presented.Propõe-se uma equação empírica que correlaciona o volume da pasta com o tempo de incubação na medida, pelo método do cilindro graduado e pasta de baixa concentração, da capacidade do fermento prensado de aumentar o volume da pasta (usualmente denominada "poder de levantamento" ou "poder de fermentação" do fermento. A equação proposta permite não apenas correlacionar o valor daquela capacidade com o tempo de incubação, mas também calcular a velocidade específica de aumento do volume da pasta em cada instante, fornecendo assim muito mais informações sobre o desempenho do fermento. Apresenta-se, também, uma possível explicação da fórmula empírica proposta.

  4. Beyond the Whole-Genome Duplication: Phylogenetic Evidence for an Ancient Interspecies Hybridization in the Baker's Yeast Lineage.

    Directory of Open Access Journals (Sweden)

    Marina Marcet-Houben

    2015-08-01

    Full Text Available Whole-genome duplications have shaped the genomes of several vertebrate, plant, and fungal lineages. Earlier studies have focused on establishing when these events occurred and on elucidating their functional and evolutionary consequences, but we still lack sufficient understanding of how genome duplications first originated. We used phylogenomics to study the ancient genome duplication occurred in the yeast Saccharomyces cerevisiae lineage and found compelling evidence for the existence of a contemporaneous interspecies hybridization. We propose that the genome doubling was a direct consequence of this hybridization and that it served to provide stability to the recently formed allopolyploid. This scenario provides a mechanism for the origin of this ancient duplication and the lineage that originated from it and brings a new perspective to the interpretation of the origin and consequences of whole-genome duplications.

  5. 游离高表达Mal62基因对面包酵母耐冷冻性的影响%Effects of High-expressed Ma162 Gene on Freezing Tolerance of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    孙溪; 张翠英; 董建; 吴鸣月; 王光路; 肖冬光

    2012-01-01

    通过测定胞内海藻糖积累量、冷冻前后相对发酵力以及存活率的变化,对比游离高表达麦芽糖酶基因(Md62)的突变株BYCPM与亲本BY14的海藻糖合成能力,研究Ma/62基因游离高表达与酵母耐冷冻性之间的关系。结果表明.Ma/62基因游离高表达与酵母耐冷冻性有一定的相关性,突变株耐冷冻性改善,其在烘焙产业中具有潜在商业价值。%AThe relations between high-expressed Ma162 gene and freezing tolerance of baker's yeast were investigated through measuring the accumulating quantity of intracellular trehalose, observing the change of cell fermenting power and cell viability before and after freezing, and com- paring trehalose synthesis of parent strain BY14 and mutant strain BYCPM. The results showed that there was certain relativity between high-expressed ma/62 gene and freezing tolerance of baker' s yeast (freezing tolerance got improved for mutant strain). Accordingly, the improved freezing tolerance of BYCPM may make it useful in commercial baking industry.

  6. KMnO4修饰面包酵母菌对Cd2+的吸附研究%Cd2+ adsorption by KMnO4 modified baker's yeast

    Institute of Scientific and Technical Information of China (English)

    姜友军; 张云松; 王仁国; 尹元江; 曾武; 肖朝萍

    2011-01-01

    研究了用KMnO4修饰面包酵母菌对溶液中Cd2+的吸附作用,探讨了不同KMnO4浓度、pH、吸附时间、Cd2+初始浓度、修饰酵母菌用量等5个因素对KMnO4修饰面包酵母菌吸附Cd2+的影响.结果表明,随着修饰剂KMnO4浓度的增大,修饰面包酵母菌的吸附能力增强,KMnO4浓度达到20 mmol·L-1时,吸附能力是相同条件下原菌的2倍.在pH为5.0~7.0范围内,吸附效果最好;反应30 min后,吸附可达到平衡;Cd2+初始浓度为100 mg·L-1时,吸附基本达到饱和;KMnO4修饰面包酵母菌的最佳用量为6 g·L-1左右.KMnO4修饰面包酵母菌吸附Cd2+的过程适宜用准二级速率方程来描述,而Langmuir方程对其吸附等温线的描述效果最好.SEM、FTIR、XPS等分析结果表明,面包酵母菌主要通过表面的羟基、羧基、氨基、磷酰基等基团进行吸附.KMnO4修饰可使面包酵母菌表面变得较为粗糙,表面结构发生变化,提高菌表面吸附镉活性位点的数量.同时,KMnO4氧化面包酵母菌时在表面被还原成纳米MnO2和Mn2+,其对Cd2+吸附也起到了协同作用.%The adsorption of aqueous Cd2+ by baker's yeast modified by KMnO4 was explored. Several factors, including the concentration of KMnO4 used to modify the baker's yeast, pH, adsorption time, the initial concentration of Cd2 + , and the dosage of KMnO4 modified yeast, were investigated to evaluate the adsorption effect. The results showed that the adsorption capacity of modified baker's yeast was improved with the increasing KMnO4 concentration and the optimal amount of KMnO4 modified baker's yeast was about 6 g·L-1. When the concentration of KMnO4 was 20 mmol·L-1 , the adsorption capacity was double that of untreated yeast under the same conditions. In the range of pH 5.0 ~ 7. 0, the adsorption was the best; adsorption equilibrium was reached at 30 min. When the initial concentration of Cd2+ was 100 mg·L-1 , KMnO4 modified baker's yeast

  7. Projeto e construção de um bioreator para síntese orgânica assimétrica catalisada por saccharomyces cerevisiae (fermento biológico de padaria Project and construction of a bioreactor for reactions catalyzed by baker's yeast (saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Ricardo de Souza Pereira

    1997-10-01

    Full Text Available A model for the construction of a simple and cheap apparatus to be used as bioreactor for reactions catalyzed by baker's yeast (Saccharomyces cerevisiae is described. The bioconversion and separation of cells from products and residual substrates are obtained at the same time. The reactions carried out in this type of reactor are faster than those catalyzed by immobilized cells. Yeast cells can be cultivated in this bioreactor operating with cell recycling at appropriated conditions using glucose and other nutrients.

  8. Entropy of Baker's Transformation

    Institute of Scientific and Technical Information of China (English)

    栾长福

    2003-01-01

    Four theorems about four different kinds of entropies for Baker's transformation are presented. The Kolmogorov entropy of Baker's transformation is sensitive to the initial flips by the time. The topological entropy of Baker's transformation is found to be log k. The conditions for the state of Baker's transformation to be forbidden are also derived. The relations among the Shanonn, Kolmogorov, topological and Boltzmann entropies are discussed in details.

  9. Correlation between the trehalose content and the stress resistance of the baker yeasts%面包酵母海藻糖含量与酵母耐性之间的关系

    Institute of Scientific and Technical Information of China (English)

    陈丽君; 肖冬光; 郭学武; 张翠英; 盖伟东

    2011-01-01

    The freeze-tolerance,the stress resistance and the trehalose content of different baker yeasts in the different periods was discussed.It was found that there was a correlation between the trehalose content and the stress resistance,and there was a better stress resistance with the higher trehalose content.%以存活率为指标,探讨了不同时期不同面包酵母的耐盐性能、耐酒精性能、耐高温性能以及耐冷冻性能,并且测定了不同时期菌体胞内海藻糖含量,研究结果表明胞内海藻糖含量与酵母的耐受性之间存在一定的相关性,海藻糖含量越高,酵母的耐性越好。

  10. Efeito da temperatura de estocagem de leveduras de panificação sobre a atividade da glicerol-3-fosfato desidrogenase The effect of storage temperature on the glycerol-3-phosphate dehydrogenase activity of baker's yeasts

    Directory of Open Access Journals (Sweden)

    Claudia Regina Cançado Sgorlon Tininis

    2002-03-01

    Full Text Available Níveis intracelulares de G-3-PDH (sn-glicerol-3-fosfato:NAD+ 2oxidoredutase, EC 1.1.1.8 de levedura de panificação foram acompanhados durante a estocagem sob três diferentes temperaturas. Semelhantes valores de biomassa final e de atividade específica da enzima foram obtidos após crescimento por 48 horas de duas linhagens de leveduras de panificação. O melhor meio (meio indutor para obtenção de G-3-PDH foi: extrato de levedura (1%,p/v, peptona (2%,p/v, glicerol (3%,v/v e etanol (1%,v/v. O choque osmótico com adição de NaCl 0,6 M provocou aumento da atividade de G-3-PDH de 1,2 vezes para leveduras crescidas em meio indutor por 48 horas e transferidas para o meio salino, por 2 horas. A estocagem (até 10 dias da linhagem de levedura GD0, sob temperatura ambiente (27 ºC estimulou a síntese da G-3-PDH de células propagadas no meio indutor, lavadas e liofilizadas. Estocagens em geladeira (temperatura de 4 - 5 ºC ou em ''freezer'' (temperatura de -18 ºC mantiveram a atividade da G-3-PDH por até 8 meses.Intracellular levels of glycerol-3-phosphate dehydrogenase (G-3-PDH in baker's yeasts were monitored during storage at 3 different temperatures. Similar values for final biomass and specific activity of the enzyme were found, in each of two strains of baker's yeast, after 48 hours growth. The best medium tested, for the induction of G-3-PDH, contained: yeast extract (1% w/v, peptone (2% w/v, glycerol (3% w/vand ethanol (1% w/v. Osmotic shock, provoked by suspending cells, after 48 hours growth in inducing medium, in 0.6 M NaCl solution for 2 hours, caused the activity to increase by a factor of 1.2. Cells of the GDO yeast strain, grown in inducing conditions, washed and lyophilized, exhibited a 35% rise in G-3-PDH activity during storage (10 days at ambient temperature (about 27 ºC. Both refrigeration (4-5 ºC and freezer storage (-18 ºC maintained the G-3-PDH activity for up to 8 months.

  11. Cryoprotective Role of Combined Emulsifiers with Soybean Lecithin and Sucrose Ester on Baker's Yeast%复配大豆磷脂和蔗糖酯对面包酵母冷冻保护作用

    Institute of Scientific and Technical Information of China (English)

    徐云峰; 杨哪; 金征宇; 谢正军; 徐学明

    2011-01-01

    The cryoprotective role of emulsifiers combined with two molar soybean lecithin and one molar sucrose ester on baker's yeast was examined in this study.The results showed that the survival ratio of yeast cultivated for 48 hours after frozen at - 30 ℃ for 5 days in a culture medium with 4 g/dL combined emulsifers increased by 60% compared with that of the control group, and the adaptive phase shorten by 10 hours.The dough made from yeast dealed with emulsifiers after frozen at -30 ℃ for 60 days had a relatively stronger ability to leaven within a short time.The phenomenon of yeast congregated with enulsifiers, which was imaged by scanning electron microscope (SEM), indicated that there might be some interaction effects between the two substances.%以质量比为2:1的大豆磷脂和蔗糖酯复配处理面包酵母,研究了其对酵母抗冻性的影响.结果表明,与未添加乳化剂组相比,酵母在-30℃含复配乳化剂质量分数为4 g/dL的YPD 培养液中冷冻贮藏5 d,解冻并于30℃平板培养48 h,存活率提高了60%,酵母生长适应期缩短了10 h左右.将乳化剂处理酵母应用于冷冻面团体系,面团经-30℃冷冻贮藏60 d后醒发时间缩短,醒发体积增大.扫描电镜观察表明酵母与乳化剂呈聚集状,存在一定的交互作用.

  12. Functional genomics of commercial baker's yeasts that have different abilities for sugar utilization and high-sucrose tolerance under different sugar conditions.

    Science.gov (United States)

    Tanaka-Tsuno, Fumiko; Mizukami-Murata, Satomi; Murata, Yoshinori; Nakamura, Toshihide; Ando, Akira; Takagi, Hiroshi; Shima, Jun

    2007-10-01

    In the modern baking industry, high-sucrose-tolerant (HS) and maltose-utilizing (LS) yeast were developed using breeding techniques and are now used commercially. Sugar utilization and high-sucrose tolerance differ significantly between HS and LS yeasts. We analysed the gene expression profiles of HS and LS yeasts under different sucrose conditions in order to determine their basic physiology. Two-way hierarchical clustering was performed to obtain the overall patterns of gene expression. The clustering clearly showed that the gene expression patterns of LS yeast differed from those of HS yeast. Quality threshold clustering was used to identify the gene clusters containing upregulated genes (cluster 1) and downregulated genes (cluster 2) under high-sucrose conditions. Clusters 1 and 2 contained numerous genes involved in carbon and nitrogen metabolism, respectively. The expression level of the genes involved in the metabolism of glycerol and trehalose, which are known to be osmoprotectants, in LS yeast was higher than that in HS yeast under sucrose concentrations of 5-40%. No clear correlation was found between the expression level of the genes involved in the biosynthesis of the osmoprotectants and the intracellular contents of the osmoprotectants. The present gene expression data were compared with data previously reported in a comprehensive analysis of a gene deletion strain collection. Welch's t-test for this comparison showed that the relative growth rates of the deletion strains whose deletion occurred in genes belonging to cluster 1 were significantly higher than the average growth rates of all deletion strains.

  13. Fed-batch cultivation of baker's yeast followed by nitrogen or carbon starvation: effects on fermentative capacity and content of trehalose and glycogen

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Olsson, Lisbeth; Rønnow, B.

    2002-01-01

    An industrial strain of Saccharomyces cerevisiae (DGI 342) was cultivated in fed-batch cultivations at a specific growth rate of 0.2 h(-1). The yeast was then exposed to carbon or nitrogen starvation for up to 8 h, to study the effect of starvation on fermentative capacity and content of protein...... of the yeast cells, and the fermentative capacity per gram dry-weight decreased by 40%. The protein content in the carbon-starved yeast increased as a result of starvation due to the fact that the content of glycogen was reduced. The fermentative capacity per gram dry-weight was, however, unaltered....

  14. Effects of mal62-overexpression on leavening ability of baker's yeast%mal62基因高表达对工业面包酵母发酵力的影响

    Institute of Scientific and Technical Information of China (English)

    孙溪; 张翠英; 董建; 王光路; 吴鸣月; 肖冬光

    2012-01-01

    [目的]构建高麦芽糖利用能力的面包酵母菌株,以期提高面包酵母在不加糖面团中的发酵力,增加经济效益的同时减少成本消耗.[方法]克隆工业面包酵母BY-14的麦芽糖酶基因mal62,以PGKl强启动子和终止子为调控元件,以酵母-大肠穿梭型质粒Yep-C为载体,构建重组表达质粒Yep-CPM,并转化酿酒酵母(Saccharomyces cerevisiae)BY-14,经筛选鉴定获得酵母转化子BYCPM.进行转化子的酶活力、mal62基因表达水平及发酵力测定,检测目的基因的功能性表达.[结果]工业酵母转化子BYCPM的最大麦芽糖酶活力比对照菌提高15% -52%,发酵力提高40%,比发酵力提高5.6%.[结论]转化子BYCPM具有更高的麦芽糖酶活力和更强的抗葡萄糖阻遏能力.并且在不加糖面团中,转化子具有更高的发酵力,可以在更短的时间内获得更大的产气量且消耗更少的碳源.%[Objective] To increase the leavening ability in the lean dough, the maltose utilization ability of baker's yeast was enhanced. [Methods] A 1.7kb PGK1 promoter and terminator were ligated and inserted into vector Yep-C to give the expression plasmid named Yep-CP. Then a 1. 7kb DNA fragment containing the open reading frame and terminator of mal62 gene was amplified from Saccharomyces cerevisiae BY-14 by PCR, and inserted into Yep-CP to generate recombinant plasmid Yep-CPM. To express mal62 gene properly in S. cerevisiae, the recombinant expression plasmids Yep-CPM with copper resistance gene as the selection marker for yeast transformation were introduced into S. cerevisiae BY-14. The resulting yeast transformant BYCPM was screened on YEPD with 4 mmol/L CuS04and identified by colony PCR. Target protein was detected by qRT-PCR, and the enzyme activities and the leavening ability of the recombinant strain BYCPM were determined to confirm whether functional expression was achieved. [ Results ] The maximum maltase activity of recombinant strain BYCPM was 15

  15. Changes in trehalose content of baker's yeast as affected by octanoic acid Alterações no teor de trealose de levedura de panificação provocadas por ácido octanóico

    Directory of Open Access Journals (Sweden)

    L.E. Gutierrez

    1993-12-01

    Full Text Available Octanoic acid inhibited ethanolic fermentation by Saccharomyces cerevisiae (bakers yeast and the trehalose accumulation, however did not affect the endogenous degradation of trehalose. This inhibition may be explained by the binding of octanoic acid to hexokinase or other proteins of plasma membrane because they are not necessary for endogenous fermentation. The degradation of trehalose may be due to an activation of trehalase.A adição de ácido octanóico inibiu a fermentação alcoólica realizada por Saccharomyces cerevisiae (levedura de panificação e o acúmulo de trealose, contudo não afetou a degradação endógena de trealose. Esta inibição poderia ser explicada pela ligação do ácido octanóico a hexoquinase ou outra proteína da membrana plasmática porque não são necessárias para a fermentação endógena. A degradação da trealose poderia ser devida a uma ativação da trealase.

  16. Effect of the variation of the level of lactose conversion in an immobilized lactase reactor upon operating costs for the production of Baker's yeast from hydrolyzed permeate obtained from the ultrafiltration of cottage cheese whey

    Energy Technology Data Exchange (ETDEWEB)

    Scott, T.C.; Hill, C.G. Jr.; Amundson, C.H.

    1987-01-01

    Operating costs for the production of Baker's yeast from hydrolyzed permeate from the ultrafiltration of cottage cheese whey were calculated as a function of the level of lactose conversion in the immobilized lactase reactor. These costs were calculated for the case of 90% conversion of lactose in the reactor and compared to those which result when running the reactor at lower conversions with recycle of unreacted lactose. Total operating costs were estimated by combining individual operating costs for the immobilized enzyme reactor, costs associated with processing a lactose recycle stream, and energy costs associated with cooling the reactor feed stream and sterilizing the hydrolysate stream. It was determined that operating costs are minimized at about 9.9 cents per pound of lactose when the reactor is run at approximately 72% conversion. This represents a savings of 2.4 cents per pound of lactose over the case of a once-through 90% conversion of lactose in the reactor. 8 refs., 4 figs., 9 tabs.

  17. Biosorption Behavior of Strontium Ions and Mechanism Analysis on Baker's Yeast%面包酵母菌对锶离子的吸附行为及其机理研究

    Institute of Scientific and Technical Information of China (English)

    代群威; 董发勤; 张伟; 李琼芳; 周世平

    2012-01-01

    The baker's yeast was utilized as biosorption material to remove Sr2+ from simulant aquous solution. The effect factors on biosorption were analyzed, which included pH values, initial concentration (c0), adsorbent concentration (pm), and temperature (0. Meanwhile, the correlation biosorption thermodynamics was analyzed and the mechanism of biosorption was researched. The results show that the optimum condition for biosorption is as follows: pH = 4. 5, t = 30 °C , c0 = 1. 0 mmol/L, pm = i. 0 g/L. The isotherm adsorption curve of Sr2+ under different temperatures accords well with the Langmuir and Freunlich absorption models, and both R2 are above 0. 988. The biosorption of Sr2+ by yeast can proceed spontaneously under different temperatures. And the higher temperature is in favour of the spontaneous process of Sr2+biosorption at the range of 10-30 °C. The analysis indicates that there is chemisorption in the course of Sr2+ biosorption by yeast. The components of yeast cell, including polysaccharide and amide protein, are involved in the Sr2+ biosorption. And the principal absorption sites are the active sites on the cell wall surface.%采用面包酵母菌为生物吸附剂,进行了模拟含锶废液中Sr2+的批量吸附实验研究.分析了液相pH、Sr2+初始浓度、菌体加入量、温度等因素对吸附效果的影响,进行了吸附热力学相关分析,并通过红外光谱、扫描电镜等探讨了其吸附机理.结果表明:实验室环境下的最佳吸附条件为pH=4.5,t=30℃,c0=1.0 mmol/L,ρm=4.0 g/L.不同温度下对Sr2-的等温吸附结果均很好地符合了Langmuir和Freunlich两个吸附模型,R2均在0.988以上.不同温度条件下酵母菌对Sr2+的吸附反应均能够自发进行,且在一定温度范围(10~30℃)内提高温度有利于酵母菌对Sr2+吸附反应的自发进行.FTIR与SEM分析结果认为,酵母菌吸附Sr2+的过程的确存在化学吸附过程,酵母菌细胞上的多糖、蛋白质酰胺

  18. Baker & Taylor's George Coe

    Science.gov (United States)

    Fialkoff, Francine

    2009-01-01

    In his 30 years as a library wholesaler, first as VP and general manager of Brodart Books, Library, and School Automation divisions and since 2000 as president of the Library & Education division of Baker & Taylor (B&T), George Coe has been instrumental in a whole host of innovations. They go way beyond the selection, processing, and delivery of…

  19. Reaction Characteristics of Asymmetric Synthesis of (2S,5S)-2,5-Hexanediol Catalyzed with Baker's Yeast Number 6%面包酵母No.6催化不对称合成(2S,5S)-2,5-已二醇反应特性

    Institute of Scientific and Technical Information of China (English)

    肖美添; 叶静; 张亚武; 黄雅燕

    2009-01-01

    Baker's yeast number 6 was selected by screening. It showed good catalytic activity and enantioselec-tivity for asymmetric reduction of 2,5-hexancdione to produce (2S,5S)-2,5-hexanediol. Gas chromatography-mass spectrometry (GC-MS) revealed that the intermediate was (S)-5-hydroxyhexane-2-one. Reduction of 2,5-hexanedione proceeded in a two-step reaction. The hydroxyketone was initially formed, and this intermediate was further re-duced to the diol. Factors influencing the product yield and the enantiomeric excess of the reduction of 2,5-hexandione catalyzed by baker's yeast number 6 were investigated. Higher concentration (≤100 mmol·L-1) of 2,5-hexandione did not influence 5-hydroxyhexane-2-one production, but 2,5-hexanediol production was inhibited by excess accumulation (>30 mmol·L-1) of intermediate. The optimal conditions were glucose as the co-substrate at an initial glucose concentration of 20 g·L-1, 34℃, pH 7.0 and cell concentration 60 g-L"1 (cell dry mass). Under the optimal condition and an initial substrate concentration of 30 mmol·L-1, the yield of 2,5-hexandiol was 78.7% and the enantiomeric excess of (2S,5S)-2,5-hexandiol was 94.4% for 24-h reduction.

  20. Irreversible quantum baker map.

    Science.gov (United States)

    Łoziński, Artur; Pakoński, Prot; Zyczkowski, Karol

    2002-12-01

    We propose a generalization of the model of classical baker map on the torus, in which the images of two parts of the phase space do overlap. This transformation is irreversible and cannot be quantized by means of a unitary Floquet operator. A corresponding quantum system is constructed as a completely positive map acting in the space of density matrices. We investigate spectral properties of this superoperator and their link with the increase of the entropy of initially pure states.

  1. Irreversible Quantum Baker Map

    CERN Document Server

    Lozinski, A; Zyczkowski, K; Lozinski, Artur; Pakonski, Prot; Zyczkowski, Karol

    2002-01-01

    We propose a generalization of the model of classical baker map on the torus, in which the images of two parts of the phase space do overlap. This transformation is irreversible and cannot be quantized by means of a unitary Floquet operator. A corresponding quantum system is constructed as a completely positive map acting in the space of density matrices. We investigate spectral properties of this super-operator and their link with the increase of the entropy of initially pure states.

  2. 基于BP神经网络和遗传算法的面包酵母高密度发酵培养基优化%Optimization of baker's yeast high density fermentation medium by optimized BP neural network based on genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    谈亚丽; 李啸; 邹嫚; 张江; 姚娟; 李知洪; 俞学锋

    2013-01-01

    为实现面包酵母的高密度发酵培养,构建一个BP神经网络模型,用于回归面包酵母高密度发酵培养基中显著影响因子与菌体密度之间的非线性关系,并在此基础上结合遗传算法进对此模型进行全局寻优,得到关键因子最佳浓度分别为:葡萄糖52.3 g/L,酵母浸出粉10.4 g/L,(NH4)2SO41.9 g/L.采用此优化配方进行摇瓶培养,所得菌体密度为3.95×108个/mL,比对照提高了61.2%.结果证实了人工神经网络的模拟和预测功能在微生物培养基优化方面有一定应用价值.%In order to fulfill the high density cultivation of baker's yeast, the back-propagation neural network was adopted to construct a nonlinear predictable model which suggested the relationship between the key factors of the culture medium and the biomass of bakers yeast. And then the global optimization on this model with the genetic algorithm was conducted. Finally the optimal dose of these significant factors was obtained; glucose 52.3 g/L, yeast extract powder 10.4 g/L, (NH4)2SO41. 9 g/L. Using this optimal medium, the biomass of the bakers yeast cultivated in shake flasks was as high as 3. 95108/mL, increased by 61. 2% compared with that of the primitive culture medium. It demonstrated that the application of artificial neural network in the optimization of microbiological culture media was feasible and efficient.

  3. Comparison of cell components in low sugar adaptation and freeze-tolerance baker's yeast with common yeast%低糖适应性耐冻酵母菌与普通酵母菌细胞构成成分的比较

    Institute of Scientific and Technical Information of China (English)

    宋振玉; 李楠; 张姝; 王雷; 居勇

    2009-01-01

    采用气相、液相色谱法和分光光度比色法,对筛选出的低糖适应性耐冻面包酵母BY-03和FY-03与普通高糖面包酵母(PT)细胞构成成分,即胞内海藻糖含量,脂肪酸组成,麦角固醇,磷脂和氨基酸组成进行了分析与比较,进而了解其对酵母耐冻性的影响.结果表明,FY-03海藻糖含量是PT含量的1.40倍,BY-03的海藻糖含量与PT含量基本持平.从3种酵母中皆检出18种氨基酸,其中有助于提高酵母耐冻性的3种带电荷氨基酸即精氨酸,脯氨酸和谷氨酸的含量,BY-03和FY-03均高于PT.从3种酵母中检出了8种饱和与不饱和的脂肪酸,其中BY-03、FY-03的不饱和脂肪酸比例分别为79.82%和78.62%,明显高于PT 64.96%,其中棕榈油酸C16∶ 1和油酸C18∶ 1的含量相差较大.麦角固醇的含量BY-03和FY-03分别为4.99mg/g和4.77mg/g显著高于PT的2.56mg/g,而三者的磷脂含量没有明显差别.%The cell components, including trehalose, fatty acid component, ergosterol, phospholipid and amino acid in the BY-03 and FY-03 were qualitatively and quantitatively determined and compared with the common baker's yeast (PT) by GC, HPLC and UV-spectrophotometer in order to find out the effects of these index on freeze-tolerance of yeast.The results suggest that the content of the trehalose in FY-03 was 1.4 times more than that in PT, while the one in BY-03 was similar to PT.Meanwhile, eighteen kinds of known amino acid were detected from three kinds of yeast.The content of the arginine, proline and glutamate, which were helpful for enhancing the ability of freeze-tolerance, in BY-03 and FY-03 were more than those in PT.Eight kinds of known saturated and unsaturated fatty acid components were detected in three kinds of yeasts. The unsaturated fatty acid in BY-03 and FY-03 were 79.82% and 78.62%, 4.99 mg/g and 4.77 mg/g, but 2.57 mg/g in PT, while the phospholipid contents were similar in all samples.

  4. Effects of Endogenous and/or Exogenous Trehalose on Freezing-tolerance of Baker's Yeast%内源与(或)外源海藻糖对面包酵母耐冷冻性的影响研究

    Institute of Scientific and Technical Information of China (English)

    王碧莹; 孙溪; 肖冬光

    2015-01-01

    通过测定胞内海藻糖降解、冷冻前后细胞存活率以及发酵力的变化,研究内源与(或)外源海藻糖对面包酵母耐冷冻性的影响。结果表明,含有较高内源海藻糖的BY14α+Tps1菌株具有更高的冷冻后细胞生存率与发酵力。外源添加5%海藻糖仅能改善较低胞内基本海藻糖含量(<10%)菌株的耐冷冻性,并且预发酵过程中海藻糖的稳定性较差(尤其前15 min)。因此,使用内源法提高胞内海藻糖含量对提升面包酵母的耐冷冻性更具可行性。%The effects of endogenous and/or exogenous trehalose on freezing-tolerance of baker's yeast were investigated through the measure-ment of cell viability and fermenting power before and after intracellular trehalose hydrolysis and freezing. The experimental results showed that BY14α+Tps1 strain with higher content of endogenous trehalose had higher cell viability and fermenting power after the freezing, and the added exogenous trehalose at the concentration of 5%could only improve the freezing-tolerance of cells with low trehalose content (<10%) but the added exogenous trehalose was apparently unstable in the prefermentation process (especially at the first 15 min after inoculation). Therefore, the method of improving endogenous trehalose in cells were feasible to strengthen freezing tolerance of baker's yeast.

  5. Chemoselective biohydrogenation of chalcone (2{Epsilon})-3-(1,3-benzodioxole-5-yl)-1-phenyl-2-propen-1-one mediated by baker yeasts immobilized in polymeric supports; Bioidrogenacao quimioseletiva da chalcona (2{Epsilon})-3-(1,3-benzodioxol-5-il)-1-fenil-2-propen-1-ona mediada por fermentos de pao imobilizado em suportes polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Mundstock, Flavia L.S.; Silva, Vanessa D.; Nascimento, Maria da G., E-mail: mundstock@qmc.ufsc.b [Universidade Federal de Santa Catarina (DQ/UFSC), Florianopolis, SC (Brazil). Dept. de Quimica

    2009-07-01

    In this study, the yeast Saccharomyces cerevisiae, baker's yeast (BY) was immobilized in poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), sodium caseinate (SC), gelatin (G) films and in agar (A) and gelatin (G) gels, and used as a biocatalyst in the biohydrogenation reaction of (2{Epsilon})-3-(1,3-benzodioxyl-5-yl)-1-phenyl-2-propen-1-one (1). The transformation of (1) into the corresponding dehydro chalcone (2) through biohydrogenation reactions was carried out in n-hexane at 25 or 35 deg C, for 4-48 h reaction. The product conversion, under different experimental conditions, was evaluated by hydrogen nuclear magnetic resonance, {sup 1}H NMR.The highest conversion degrees were achieved using BY immobilized in agar gel, (29-47%), depending also on the temperature. Using BY immobilized in PEO, PVA, SC and G films, the conversion into (2) was lower (0-21%). The results show the feasibility of the use of BY immobilized in polymeric materials to reduce a,b-unsaturated carbonyl compounds. (author)

  6. Obituary: Dr. Richard Roland Baker

    Directory of Open Access Journals (Sweden)

    Thornton R

    2014-12-01

    Full Text Available Richard Baker died at Easter 2007 after a very short illness. It is sad that he died so soon after his retirement from the British American Tobacco Company at the end of 2005, and just as he was beginning to enjoy his new life, even though tobacco science still had a part to play.

  7. 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.

  8. The Peano-Baker series

    CERN Document Server

    Baake, Michael

    2010-01-01

    This note reviews the Peano-Baker series and its use to solve the general linear system of ODEs. The account is elementary and self-contained, and is meant as a pedagogic introduction to this approach, which is well known but usually treated as a folklore result or as a purely formal tool. Here, a simple convergence result is given, and two examples illustrate that the series can be used explicitly as well.

  9. 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

  10. Chromium uptake from aqueous effluents by immobilized Baker's yeast Utilização de leveduras de panificação na remoção de cromo em meio aquoso

    Directory of Open Access Journals (Sweden)

    Lucia Beckmann C. Menezes

    1998-10-01

    Full Text Available Baker’s yeast immobilized in alginate was used to take up chromium from effluents. Chromium in aqueous solutions were used in different concentrations. To evaluate the viability and efficiency the baker’s yeast for chromium uptake from effluents three experiments done in two differents reactor systems: first in system 1 at 17.5 ml/s and with 10, 20, 25 and 30 mg/l Cr; second in system 2 at 38.7 ml/s with 20 mg/l Cr; third in system 2.1 at 6.65 ml/s and with 20, 30 and 40 mg/l Cr. The efficiency of chromium uptake varied between 86 and 100 %.Leveduras de panificação imobilizadas em alginato, foram utilizadas com o objetivo de promover a remoção de cromo presente em efluentes. Trabalhou-se com soluções de cromo de diferentes concentrações. A fim de avaliar a viabilidade e eficiência do uso de leveduras de panificação na remoção de cromo, três experimentos foram realizados em dois diferentes sistemas de reatores: o primeiro no sistema 1 com 17,5 ml/s e 10, 20, 25 e 30 mg/l Cr; o segundo no sistema 2 com 38,7 ml/s e 20 mg/l Cr; o terceiro no sistema 2.1 com 6,65 ml/s e 20, 30 e 40 mg/l Cr. A média das eficiências de retenção do cromo variaram entre 86 e 100%.

  11. 富铁面包酵母的筛选及富集条件研究%Isolation and Accumulation Conditions of Iron-enrich Baker ’s Yeast

    Institute of Scientific and Technical Information of China (English)

    李静; 谭海刚; 王滢雪

    2014-01-01

    本文探索获得富铁面包酵母的富集条件。筛选获得一株富铁能力较强的面包酵母菌株QN006。通过单因素实验确定该菌株富铁工艺条件为:铁盐种类为硫酸亚铁,亚铁离子浓度为900μg/mL,添加时间为0h,温度为28℃, pH为5.0。在此条件测得面包酵母QN006的铁富集量为13.92mg/g干菌体,不加糖面团发酵力达到623mL/h。%To explore the accumulation conditions of baker’s yeast which is able to enrich iron. The baker’s yeast strain QN006 with strong iron-rich ability was obtained. By the single factor test, the accumulation conditions of iron-rich were as follows: the inorganic ferrite was FeSO4, the content of Fe2+ was 900μg/mL, the adding time was 0h, the accumulation temperature was 28℃, and the accumulation pH was 5.0. Under these conditions, the iron content and the CO2 production in lean dough of QN006 reached 13.92mg/g (cell dry weight) and 623mL/h, re-spectively.

  12. Cloning and Expression of Maltase Encoding Gene from Baker's Yeast and Optimization of the Expression Conditions%面包酵母麦芽糖酶的异源表达及产酶条件优化

    Institute of Scientific and Technical Information of China (English)

    宋海岩; 林雪; 柏晓雯; 张翠英; 肖冬光

    2015-01-01

    通过设计特异性引物从快速发酵面包酵母BY-14中PCR克隆获得麦芽糖酶编码基因。选择BamH I和Hind III分别为上下游引物的酶切位点,将麦芽糖酶基因克隆到pET28a载体上。表达质粒经PCR扩增、双酶切和测序进行验证。正确的表达质粒pET28a-Mal62导入大肠杆菌宿主BL(21),经IPTG诱导表达,结果显示,重组蛋白能够可溶性表达。随后对大肠杆菌产酶条件进行优化,结果表明,当IPTG终浓度为0.4 mmol/L,菌浓OD600达到1.0时加入诱导剂,在26℃下振荡培养12 h可获得最高的产酶量39.9 U/L,比优化前提高了4倍。%The maltase encoding gene was amplified via PCR from baker’s yeast. Then it was digested by BamH I and Hind III, and inserted in-to plasmid pET28a. The expression plasmid was identified via PCR, restriction endonuclease digestion and sequencing. The valid expression plasmid (pET28a-Mal62) was transformed into competence Escherichia coli BL(21) for heterologous expression. The experimental results showed that, the target protein was able to be expressed and most of them were soluble. Afterwards, the expression conditions for the target pro-tein was optimized as follows:as IPTG concentration was 0.4 mmol/L, the induced timing OD600 for 1.0, oscillation induced culture for 12 h at 26℃, it was feasible to express the recombinant fusion protein in the supernatant with the highest production of 39.9 U/L, which increased by 4 fold compared with unoptimized conditions.

  13. Pühendusega isadele - Baker Street

    Index Scriptorium Estoniae

    2009-01-01

    Üritusest 7. novembril Kuressaares Arensburg lounge-restoranis Muusa toimuvast isadepäevahõngulisest üritusest, esinevad Virgo Veldi & Band kavaga "Baker Street", erikülalisena Villu Veski. Saksofonistist Virgo Veldist

  14. CRED REA Algal Assessments, Baker Island 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 8 sites at Baker Island in the US...

  15. The Purification of Cytochrome C from Bakers' Yeast.

    Science.gov (United States)

    Lambeth, David O.

    1979-01-01

    This undergraduate biochemistry experiment introduces the student to techniques for cell lysis and release of protein from the cell in soluble form, ion exchange and gel chromatography, and dialysis. (Author/BB)

  16. Improved vanillin production in baker's yeast through in silico design

    DEFF Research Database (Denmark)

    Brochado, Ana Rita; Matos, Cláudia; Møller, Birger L.;

    2010-01-01

    (PDC1 and GDH1) were selected for experimental verification resulting in four engineered strains. Three of the mutants showed up to 1.5 fold higher vanillin beta-D-glucoside yield in batch mode, while continuous culture of the Delta pdc1 mutant showed a 2-fold productivity improvement. This mutant...

  17. Some Aspects of Catalase Induction in Baker's Yeast (Saccharomyces cerevisiae)

    Science.gov (United States)

    Freeland, P. W.

    1974-01-01

    Described are experiments for demonstrating essential features of substrate-induced enzyme synthesis based on the Jacob-Monod model, and for showing that the activity of certain genes can be modified by environmental temperature. (RH)

  18. 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.

  19. Bakers' asthma caused by alpha amylase.

    Science.gov (United States)

    Valdivieso, R; Subiza, J; Subiza, J L; Hinojosa, M; de Carlos, E; Subiza, E

    1994-10-01

    Two bakers with bronchial asthma and two with rhinoconjunctivitis are described. Prick and RAST tests were positive with wheat flour in all of them, but the challenge test (nasal or bronchial) with wheat flour extract was positive only in one asthmatic baker. The prick test, RAST, and nasal or bronchial challenge done with alpha amylase extract (a glycolytic enzyme obtained from Aspergillus oryzae and used as a flour additive) were positive in all four patients. Our results support previous data indicating that alpha amylase used in bakeries is an important antigen that could cause respiratory allergy in bakers. It can function as sole causative allergen or in addition with other allergens used in the baking industry.

  20. Effects of inoculated density and baker yeast ration on population dynamics and yield of Moina mongolica%接种密度和面包酵母投喂量对蒙古裸腹溞种群变动和生产量的影响

    Institute of Scientific and Technical Information of China (English)

    李蕾; 王岩; 楼宝

    2005-01-01

    在室内水槽中进行蒙古裸腹溞(Moina mongolica)的大量培养,研究不同接种密度和面包酵母投喂水平对该溞种群变动和生产量的影响.所用蒙古裸腹溞为20世纪90年代采自山西省晋南半咸水湖、在海水中长期培养保存下的溞种.实验1中,接种密度分别设为338 ind/L、145 ind/L和88 ind/L 3个水平,面包酵母投喂量为5 mg/L,每天4次,各设3个重复.实验2中,面包酵母投喂量分别为30 mg/(L·d)、20 mg/(L·d)和10 mg/(L·d) 3个水平,蒙古裸腹溞接种密度为900 ind/L,各设3个重复.实验结果表明:(1)在一定范围内蒙古裸腹溞培养产量随接种密度增加而增加,当接种密度低于88 ind/L时,接种的蒙古裸腹溞较难形成稳定的种群.(2)当使用面包酵母(Baker yeast)作为培养蒙古裸腹溞的惟一食物时,食物需要量随溞种群密度的变化而变化.当溞密度低于1 500 ind/L时,适宜的面包酵母投喂水平为20 mg/(L·d);当溞密度超过5 000 ind/L时为30 mg/(L·d).上述结果显示,接种密度和面包酵母投喂量对蒙古裸腹溞种群变动和生产量具有重要影响.建议在蒙古裸腹溞培养生产中接种密度高于150 ind/L,面包酵母投喂量为0.8×10-5~1.3×10-5 g/(ind·d).

  1. Yeast expressing hepatitis B virus surface antigen determinants on its surface: Implications for a possible oral vaccine

    NARCIS (Netherlands)

    Schreuder, M.P.; Deen, C.; Boersma, W.J.A.; Pouwels, P.H.; Klis, F.M.

    1996-01-01

    The two major hydrophilic regions of the hepatitis B virus surface antigen (HBsAg) have been expressed in the outer mannoprotein layer of the cell wall of 'Bakers Yeast', Saccharomyces cerevisiae, by fusing them between the yeast invertase signal sequence and the yeast α-agglutinin carboxyterminal c

  2. Deformation of Entire Functions with Baker Domains

    DEFF Research Database (Denmark)

    Fagella, Nuria; Henriksen, Christian

    2006-01-01

    We consider entire transcendental functions f with an invariant (or periodic) Baker Domain. First, we classify these domains into three types (hyperbolic, simply parabolic and doubly parabolic) according to the surface they induce when we take the quotient by the dynamics. Second, we study...

  3. 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.

  4. 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

  5. Water-quality effects on Baker Lake of recent volcanic activity at Mount Baker, Washington

    Science.gov (United States)

    Bortleson, Gilbert Carl; Wilson, Reed T.; Foxworthy, B.L.

    1976-01-01

    Increased volcanic activity on Mount Baker, which began in March 1975, represents the greatest known activity of a Cascade Range volcano since eruptions at Lassen Peak, Calif. during 1914-17. Emissions of dust and increased emanations of steam, other gases, and heat from the Sherman Crater area of the mountain focused attention on the possibility of hazardous events, including lava flows, pyroclastic eruptions, avalanches, and mudflows. However, the greatest undesirable natural results that have been observed after one year of the increased activity are an increase in local atmospheric pollution and a decrease in the quality of some local water resources, including Baker Lake. Baker Lake, a hydropower reservoir behind Upper Baker Dam, supports a valuable fishery resource and also is used for recreation. The lake's feedwater is from Baker River and many smaller streams, some of which, like Boulder Creek, drain parts of Mount Baker. Boulder Creek receives water from Sherman Crater, and its channel is a likely route for avalanches or mudflows that might originate in the crater area. Boulder Creek drains only about 5 percent of the total drainage area of Baker Lake, but during 1975 carried sizeable but variable loads of acid and dissolved minerals into the lake. Sulfurous gases and the fumarole dust from Sherman Crater are the main sources for these materials, which are brought into upper Boulder Creek by meltwater from the crater. In September 1973, before the increased volcanic activity, Boulder Creek near the lake had a pH of 6.0-6.6; after the increase the pH ranged as low as about 3.5. Most nearby streams had pH values near 7. On April 29, in Boulder Creek the dissolved sulfate concentration was 6 to 29 times greater than in nearby creeks or in Baker River; total iron was 18-53 times greater than in nearby creeks; and other major dissolved constituents generally 2 to 7 times greater than in the other streams. The short-term effects on Baker Lake of the acidic

  6. Quantum Baker map on the sphere

    CERN Document Server

    Pakonski, P; Zyczkowski, K; Pakonski, Prot; Ostruszka, Andrzej; Zyczkowski, Karol

    1998-01-01

    We construct analogue of the baker map on the sphere. We analyze its classical and quantum versions. The classical map is characterized by dynamical entropy equal to ln(2) and has a similar set of periodic orbits as the map on the torus. The quantum map is represented by a real, orthogonal matrix of an even dimension. Semiclassical dynamics and time evolution may be studied with the help of the SU(2) coherent states and the generalized Husimi distribution. In contrast to the standard baker map on the torus, the map analyzed in this paper does not exhibit the time reversal symmetry. Semiclassical ensemble of quantum maps, obtained by averaging over a range of matrix sizes, displays statistical properties characteristic of circular unitary ensemble.

  7. Wheat allergens associated with Baker's asthma.

    Science.gov (United States)

    Salcedo, G; Quirce, S; Diaz-Perales, A

    2011-01-01

    Baker's asthma is a frequent occupational allergic disease caused mainly by inhalation of cereal flour, particularly wheat flour. This review deals with the current diagnosis and immunomodulatory treatments, as well as the role of wheat allergens as molecular tools to enhance management and knowledge of this disease. The review also discusses the current status of several salt-soluble proteins (albumins and globulins)--cereal alpha-amylase/trypsin inhibitors, peroxidase, thioredoxin, nonspecific lipid transfer protein, serine proteinase inhibitor, and thaumatin-like protein-as well as salt-insoluble storage proteins (prolamins, namely, gliadins and glutenins) as allergens associated with baker's asthma. Finally, current limitations to using these proteins as molecular tools for diagnosis and immunotherapy are highlighted.

  8. Yeast genome duplication was followed by asynchronous differentiation of duplicated genes

    DEFF Research Database (Denmark)

    Langkjær, Rikke Breinhold; Cliften, P.F.; Johnston, M.

    2003-01-01

    Gene redundancy has been observed in yeast, plant and human genomes, and is thought to be a consequence of whole-genome duplications(1-3). Baker's yeast, Saccharomyces cerevisiae, contains several hundred duplicated genes(1). Duplication(s) could have occurred before or after a given speciation. ...

  9. Natural and modified promoters for tailored metabolic engineering of the yeast Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Hubmann, Georg; Thevelein, Johan M; Nevoigt, Elke

    2014-01-01

    The ease of highly sophisticated genetic manipulations in the yeast Saccharomyces cerevisiae has initiated numerous initiatives towards development of metabolically engineered strains for novel applications beyond its traditional use in brewing, baking, and wine making. In fact, baker's yeast has be

  10. Reduction of toxic effects of aflatoxin B1 by using baker yeast (Saccharomyces cerevisiae in growing broiler chicks diets Redução dos efeitos tóxicos da aflatoxina B1, utilizando-se levedura de panificação (Saccharomyces cerevisiae, na dieta de pintos de corte em crescimento

    Directory of Open Access Journals (Sweden)

    Kemal Çelýk

    2003-06-01

    Full Text Available This study was carried out to investigate the effects of adding baker yeast (BY, chlortetracycline (CTC and both BY + CTC to a control diet containing 200 ng/g of aflatoxin B1 (C + AFB1 on performance, serum parameters and pathologyc alterations of broilers. A total 100 chicks (Ross PM 3 were divided into five groups in individual cages and each containing 20 animals. BY, a rich source of protein and vitamin B complex, was mixed into the diets at 2.0 %, CTC was mixed into the diet at 2.5 ng/g. Feed consumption, body weight and feed efficiency were recorded weekly. Serum parameters and pathologyc alterations were determined at the end of the study. Dead animals were recorded daily. Liver changes were clearly apparent in the C+AFB1and C+ AFB1+CTC most of the livers were enlarged, yellow and had pethecial hemorrhages. Canalicula cholestosis was absent in group C+AFB1 and C+ AFB1+CTC, but not others. When compared to the control (C group, alkaline phosphatase (ALP, appear to be significantly increased in the C+AFB1 and C+CTC+ AFB1 groups. Serum glutamic oxalacetic transaminase (GOTwas increased in C+AFB1 birds. Serum alphaphetoprotein was not affected by the treatments. Feed consumption and body weight were significantly reduced in group AFB1. Birds receiving BY + AFB1, CTC + AFB1 and BY + CTC + AFB1 had a significantly higher body weight than group C+AFB1. Feed efficiency was better in group CTC + AFB1 than the others. The findings of this research suggest tha BY (2% can partly counteract some of the toxic effects of AFB1.Este estudo foi desenvolvido para avaliar os efeitos da adição de Levedura de panificação (BY e cortetraciclina (CTC e ambos BY+CTC a uma dieta controle © contendo 200 ng/g de aflatoxina B1 (C+AFB1 sobre desempenho, parâmetros séricos e alterações patológicas de frangos de corte. Um total de 100 pintinhos (Ross PM3 foi dividido em cinco grupos, em gaiolas individuais, contendo 20 animais para cada grupo. A levedura de

  11. 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

  12. Obituary: James Gilbert Baker, 1914-2005

    Science.gov (United States)

    Baker, Neal Kenton

    2005-12-01

    Dr. James Gilbert Baker, renowned astronomer and optical physicist, died 29 June 2005 at his home in Bedford, New Hampshire at the age of 90. Although his scientific interest was astronomy, his extraordinary ability in optical design led to the creation of hundreds of optical systems that supported astronomy, aerial reconnaissance, instant photography (Polaroid SX70 camera), and the US space programs. He was the recipient of numerous awards for his creative work. He was born in Louisville, Kentucky, on 11 November 1914, the fourth child of Jesse B. Baker and Hattie M. Stallard. After graduating from Louisville DuPont Manual High, he went on to attend the University of Louisville majoring in Mathematics. He became very close to an Astronomy Professor, Dr. Moore, and many times used his telescopes to do nightly observations. While at the university, he built mirrors for his own telescopes and helped form the Louisville Astronomical Society in 1933. At the University of Louisville, he also met his future wife, Elizabeth Katherine Breitenstein of Jefferson County, Kentucky. He received his BA in 1935 at the height of the Depression. He began his graduate work in astronomy at the Harvard College Observatory. After his MA (1936), he was appointed a Junior Fellow (1937-1943) in the Prestigious Harvard Society of Fellows. He received his PhD in 1942 from Harvard in rather an unusual fashion, which is worth retelling. During an Astronomy Department dinner, Dr. Harlow Shapley (the director) asked him to give a talk. According to the "Courier-Journal Magazine", "Dr. Shapley stood up and proclaimed an on-the-spot departmental meeting and asked for a vote on recommending Baker for a Ph.D. on the basis of the 'oral exam' he had just finished. The vote was unanimous." It was at Harvard College Observatory during this first stage of his career that he collaborated with Donald H. Menzel, Lawrence H. Aller, and George H. Shortley on a landmark set of papers on the physical processes

  13. Experimental implementation of the quantum baker's map.

    Science.gov (United States)

    Weinstein, Yaakov S; Lloyd, Seth; Emerson, Joseph; Cory, David G

    2002-10-07

    This Letter reports on the experimental implementation of the quantum baker's map via a three bit nuclear magnetic resonance quantum information processor. The experiments tested the sensitivity of the quantum chaotic map to perturbations. In the first experiment, the map was iterated forward and then backward to provide benchmarks for intrinsic errors and decoherence. In the second set of experiments, the least significant qubit was perturbed in between the iterations to test the sensitivity of the quantum chaotic map to controlled perturbations. These experiments can be used to investigate existing theoretical predictions for quantum chaotic dynamics.

  14. Study on Biological Characters of Asparagus macowanii Baker.

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Asparagus macowanfi Baker, is a climbing herbaceous foliage species in genus Asparagus of Liliaceae, This paper summarized its multiple uses, morphologi- cal characteristics, biological habit, reproduction methods, management after cultiva- tion, prevention and control of pests and disease, as well as harvest and grading, with the objective to provide references for the exploitation and utilization of As- paragus macowanii Baker.

  15. Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models

    NARCIS (Netherlands)

    Pfohl-Leszkowicz, A; Hadjeba-Medjdoub, K; Ballet, N; Schrickx, J; Fink-Gremmels, J

    2015-01-01

    The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding stu

  16. Phenolics from Kalanchoe marmorata Baker, Family Crassulaceae

    Directory of Open Access Journals (Sweden)

    Abdel Nasser Badawy Singab

    2011-06-01

    Full Text Available In search of plants rich in phenolics in Egypt, Kalanchoe marmorata Baker was subjected to phytochemical study. The preliminary phytochemical screening revealed its richness in phenolics. Fractionation of the lyophilized aqueous extract of the leaves of K. marmorata by different organic solvents successively resulted in the isolation and purification of five compounds from the ethyl acetate soluble fraction. These compounds namely; E1 isorhamnetin-3-O-α-l-1C4-rhamnopyranoside; E2 quercitin; E3 4′-methoxy-myricetin-3-O-α-l-1C4-rhamnopyranoside; E4 Quercitin-3-O-β-d-4C1-glucopyranoside and E5 protocatechuic-4′-O-β-d-4C1-glucopyranoside, were identified by analysis of their spectral data including 1H NMR and 13C NMR.

  17. Lectotypification of Kniphofia pauciflora Baker (Asphodelaceae: Asphodeloideae

    Directory of Open Access Journals (Sweden)

    Himansu Baijnath

    2014-07-01

    Full Text Available Background: Problems amongst the syntypes and duplicates were noted for the critically endangered Kniphofia pauciflora Baker.Objective: To resolve the typification of K. pauciflora.Method: Literature and specimens (including type material were examined from relevant herbaria.Results: Lectotypification was necessary in this case. The lectotype designated was Wood 1096 (K from ‘Natal, Claremont flat’ [KwaZulu-Natal, Clairmont flat]. This was undertaken to specify a single type specimen and to clarify the status of the duplicates. Also included is an account of the last remaining population of K. pauciflora at the Clairwood Racecourse, Durban, South Africa.Conclusion: The lectotype was designated as Wood 1096 (K.

  18. Baker-Akhiezer functions and generalised Macdonald-Mehta integrals

    Science.gov (United States)

    Feigin, M. V.; Hallnäs, M. A.; Veselov, A. P.

    2013-05-01

    For the rational Baker-Akhiezer functions associated with special arrangements of hyperplanes with multiplicities we establish an integral identity, which may be viewed as a generalisation of the self-duality property of the usual Gaussian function with respect to the Fourier transformation. We show that the value of properly normalised Baker-Akhiezer function at the origin can be given by an integral of Macdonald-Mehta type and explicitly compute these integrals for all known Baker-Akhiezer arrangements. We use the Dotsenko-Fateev integrals to extend this calculation to all deformed root systems, related to the non-exceptional basic classical Lie superalgebras.

  19. 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.

  20. CRED REA Coral Population Parameters at Baker, Phoenix Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 2 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 3 sites at Baker in the Phoenix...

  1. CRED REA Algal Assessments, Baker Island 2004 (NODC Accession 0010352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines as part of Rapid Ecological Assessments conducted at 6 sites at Baker Island in the US...

  2. Occurrence of self reported hand eczema in Swedish bakers

    OpenAIRE

    1998-01-01

    OBJECTIVES: To estimate the risk of bakers developing hand eczema. The importance of atopy was studied as well as change of job due to hand eczema. METHODS: A retrospective cohort study was performed among bakers trained in Swedish trade schools in 1961-89 (n = 2923). School referents followed other programmes (n = 1258); population controls were randomly selected from the general population (n = 1258). A questionnaire on self reported hand eczema, year of onset of hand eczema, change o...

  3. On a three-dimensional implementation of the baker's transformation

    Science.gov (United States)

    Carrière, Philippe

    2007-11-01

    A three-dimensional, steady flow configuration intended to mimic the baker's map is studied by means of numerical simulation. The Poincaré sections computed from a finite element solution of the velocity field show that the behavior is dominated by chaotic advection. The value obtained for the Lyapunov exponent is very close to the theoretical value of ln2 predicted by the baker's map.

  4. 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.

  5. Horizontal gene transfer promoted evolution of the ability to propagate under anaerobic conditions in yeasts

    DEFF Research Database (Denmark)

    Gojkovic, Zoran; Knecht, Wolfgang; Warneboldt, J.;

    2004-01-01

    The ability to propagate under anaerobic conditions is an essential and unique trait of brewer's or baker's yeast (Saccharomyces cervisiae). To understand the evolution of facultative anaerobiosis we studied the dependence of de novo pyrimidine biosynthesis, more precisely the fourth enzymic...... a bacterial gene for DHODase, which subsequently allowed cell growth gradually to become independent of oxygen....

  6. Purification and Characterization of Enzymes from Yeast: An Extended Undergraduate Laboratory Sequence for Large Classes

    Science.gov (United States)

    Johanson, Kelly E.; Watt, Terry J.; McIntyre, Neil R.; Thompson, Marleesa

    2013-01-01

    Providing a project-based experience in an undergraduate biochemistry laboratory class can be complex with large class sizes and limited resources. We have designed a 6-week curriculum during which students purify and characterize the enzymes invertase and phosphatase from bakers yeast. Purification is performed in two stages via ethanol…

  7. Observing reducing effect of N-acetylcysteine in the metabolism of yeast

    Directory of Open Access Journals (Sweden)

    Sebastián Chapela

    2016-06-01

    Full Text Available The research focuses on the design of experimental teaching using readily available materials and simple methods to implement. It arises as an example for learning, using baker's yeast Saccharomyces cerevisiae, because it has many of the metabolic pathways existing in mammalian cells. In this paper it was developed an essay that allow students to observe macroscopically the capacity of N- Acetyl cysteine (NAC to stimulate the reducing power of yeast using indicator Methylene Blue (MB color change.

  8. USA sender Able og Baker en tur i rummet

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen

    2014-01-01

    DETTE ER DEN TREDJE ARTIKEL I SERIEN OM DYRENES ROLLE I RUMFORSKNINGEN. VI SKAL MØDE DE TO PRIMATER ABLE OG BAKER, SOM NASA SUCCESFULDT SENDTE EN TUR I RUMMET I MAJ 1959 – HALVANDET ÅR EFTER, AT SOVJETUNIONEN HAVDE SENDT HUNDEN LAIKA DERUD.......DETTE ER DEN TREDJE ARTIKEL I SERIEN OM DYRENES ROLLE I RUMFORSKNINGEN. VI SKAL MØDE DE TO PRIMATER ABLE OG BAKER, SOM NASA SUCCESFULDT SENDTE EN TUR I RUMMET I MAJ 1959 – HALVANDET ÅR EFTER, AT SOVJETUNIONEN HAVDE SENDT HUNDEN LAIKA DERUD....

  9. Hypersensitivity to Perturbations in the Quantum baker's Map

    CERN Document Server

    Schack, R

    1999-01-01

    We analyze a randomly perturbed quantum version of the baker's transformation, a prototype of an area-conserving chaotic map. By numerically simulating the perturbed evolution, we estimate the information needed to follow a perturbed Hilbert-space vector in time. We find that the Landauer erasure cost associated with this information grows very rapidly and becomes much larger than the maximum statistical entropy given by the logarithm of the dimension of Hilbert space. The quantum baker's map thus displays a hypersensitivity to perturbations that is analogous to behavior found earlier in the classical case. This hypersensitivity characterizes ``quantum chaos'' in a way that is directly relevant to statistical physics.

  10. Data-Based Personnel Decisions: Baker Middle's Intensive Support List

    Science.gov (United States)

    Hewitt, Kimberly Kappler; Chopin, Scarlet Lilian

    2015-01-01

    Focused on the use of teacher evaluation data, this case was designed for use in two principal licensure courses, one on data literacy and the other on supervision and personnel. The principal of Baker Middle School has been instructed by the superintendent to use data from the state's new teacher evaluation system to determine which teachers…

  11. A note on the infinitesimal Baker-Campbell-Hausdorff formula

    OpenAIRE

    Nishimura, Hirokazu; Takamiya, Hirowaki

    2015-01-01

    We have studied the infinitesimal Baker-Campbell-Hausdorff formula up to n=4 (Math. Appl. 2 (2013), 61-91). In this note we correct some errors in our calculation for n=4 and presents the calculation for n=5 by using Mathematica.

  12. Stego Optical Encryption Based on Chaotic Baker's Map Transformation

    Science.gov (United States)

    Hussain, Iqtadar; Gondal, Muhammad Asif

    2014-06-01

    In this article, an optical image encryption algorithm based on chaotic baker's map is presented. The stego-image is encrypted with the help of double random phase encoding algorithm and then produced disorder with the help of chaotic transformation. Security test shows that the reading of proposed algorithm is very close to the optimal values.

  13. 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.

  14. 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.

  15. The Classical and Quantum Mechanics of lazy baker Maps

    CERN Document Server

    Lakshminarayan, A

    1993-01-01

    We introduce and study the classical and quantum mechanics of certain non hyperbolic maps on the unit square. These maps are modifications of the usual baker's map and their behaviour ranges from chaotic motion on the whole measure to chaos on a set of measure zero. Thus we have called these maps ``lazy baker maps.'' The aim of introducing these maps is to provide the simplest models of systems with a mixed phase space, in which there are both regular and chaotic motions. We find that despite the obviously contrived nature of these maps they provide a good model for the study of the quantum mechanics of such systems. We notice the effect of a classically chaotic fractal set of measure zero on the corresponding quantum maps, which leads to a transition in the spectral statistics. Some periodic orbits belonging to this fractal set are seen to scar several eigenfunctions.

  16. Coupled modified baker's transformations for the Ising model.

    Science.gov (United States)

    Sakaguchi, H

    1999-12-01

    An invertible coupled map lattice is proposed for the Ising model. Each elemental map is a modified baker's transformation, which is a two-dimensional map of X and Y. The time evolution of the spin variable is memorized in the binary representation of the Y variable. The temporal entropy and time correlation of the spin variable are calculated from the snapshot configuration of the Y variables.

  17. Microfluidic baker's transformation device for three-dimensional rapid mixing.

    Science.gov (United States)

    Yasui, Takao; Omoto, Yusuke; Osato, Keiko; Kaji, Noritada; Suzuki, Norikazu; Naito, Toyohiro; Watanabe, Masaki; Okamoto, Yukihiro; Tokeshi, Manabu; Shamoto, Eiji; Baba, Yoshinobu

    2011-10-01

    We developed a new passive-type micromixer based on the baker's transformation and realized a fast mixing of a protein solution, which has lower diffusion constant. The baker's transformation is an ideal mixing method, but there is no report on the microfluidic baker's transformation (MBT), since it is required to fabricate the complicated three-dimensional (3D) structure to realize the MBT device. In this note, we successfully fabricate the MBT device by using precision diamond cutting of an oxygen-free copper substrate for the mould fabrication and PDMS replication. The MBT device with 10.4 mm mixing length enables us to achieve complete mixing of a FITC solution (D = 2.6 × 10(-10) m(2) s(-1)) within 51 ms and an IgG solution (D = 4.6 × 10(-11) m(2) s(-1)) within 306 ms. Its mixing speed is 70-fold higher for a FITC solution and 900-fold higher for an IgG solution than the mixing speed by the microchannel without MBT structures. The Péclet number to attain complete mixing in the MBT device is estimated to be 6.9 × 10(4).

  18. Latest Pleistocene and Holocene glacier fluctuations on Mount Baker, Washington

    Science.gov (United States)

    Osborn, Gerald; Menounos, Brian; Ryane, Chanone; Riedel, Jon; Clague, John J.; Koch, Johannes; Clark, Douglas; Scott, Kevin; Davis, P. Thompson

    2012-08-01

    Glaciers on stratovolcanoes of the Pacific Northwest of North America offer opportunities for dating late Pleistocene and Holocene glacier advances because tephra and fossil wood are common in lateral moraines and in glacier forefields. We capitalize on this opportunity by examining the Holocene glacial record at Mount Baker, an active stratovolcano in northwest Washington. Earlier workers concluded that glaciers on Mount Baker during the early Holocene were more extensive than during the Little Ice Age and hypothesized that the explanation lay in unusual climatic or hypsometric effects peculiar to large volcanoes. We show that the main argument for an early Holocene glacier advance on Mount Baker, namely the absence of ca 10,000-year-old tephra on part of the south flank of the mountain, is incorrect. Moreover, a lake-sediment core indicates that a small cirque moraine previously thought be of early Holocene age is also likely older than the tephra and consequently of late Pleistocene age. Lateral and end moraines and wood mats ca 2 km downvalley of the present snout of Deming Glacier indicate that an advance during the Younger Dryas interval was little more extensive than the climactic Little Ice Age advance. Tephra and wood between tills in the left lateral moraine of Easton Glacier suggest that ice on Mount Baker was restricted in the early Holocene and that Neoglaciation began ca 6 ka. A series of progressively more extensive Neoglacial advances, dated to about 2.2, 1.6, 0.9, and 0.4 ka, are recorded by stacked tills in the right lateral moraine of Deming Glacier. Intervening retreats were long enough to allow establishment of forests on the moraine. Wood mats in moraines of Coleman and Easton glaciers indicate that Little Ice Age expansion began before 0.7 ka and was followed by retreat and a readvance ca 0.5 ka. Tree-ring and lichen data indicate glaciers on the south side of the mountain reached their maximum extents in the mid-1800s. The similarity between

  19. Monkey Baker at U.S. Space and Rocket Center in Huntsville, Alabama

    Science.gov (United States)

    1958-01-01

    On May 28, 1958, Jupiter Intermediate Range Ballistic Missile provided by U.S. Army team in Huntsville, Alabama, launched a nose cone carrying Baker, a South American squirrel monkey and Able, an American-born rhesus monkey. Baker, pictured here and commonly known as 'Miss Baker', was later given a home at the U.S. Space and Rocket Center until her death on November 29, 1984. Able died in 1958. (Photo - Courtesy of Huntsville/Madison County Public Library)

  20. 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.

  1. On the equivalence between stochastic baker's maps and two-dimensional spin systems

    Science.gov (United States)

    Lindgren, K.

    2010-05-01

    We show that there is a class of stochastic bakers transformations that is equivalent to the class of equilibrium solutions of two-dimensional spin systems with finite interaction. The construction is such that the equilibrium distribution of the spin lattice is identical to the invariant measure in the corresponding bakers transformation. We illustrate the equivalence by deriving two stochastic bakers maps representing the Ising model at a temperature above and below the critical temperature, respectively. A calculation of the invariant measure and the free energy in the baker system is then shown to be in agreement with analytic results of the two-dimensional Ising model.

  2. Direct concentration and viability measurement of yeast in corn mash using a novel imaging cytometry method.

    Science.gov (United States)

    Chan, Leo L; Lyettefi, Emily J; Pirani, Alnoor; Smith, Tim; Qiu, Jean; Lin, Bo

    2011-08-01

    Worldwide awareness of fossil-fuel depletion and global warming has been increasing over the last 30 years. Numerous countries, including the USA and Brazil, have introduced large-scale industrial fermentation facilities for bioethanol, biobutanol, or biodiesel production. Most of these biofuel facilities perform fermentation using standard baker's yeasts that ferment sugar present in corn mash, sugar cane, or other glucose media. In research and development in the biofuel industry, selection of yeast strains (for higher ethanol tolerance) and fermentation conditions (yeast concentration, temperature, pH, nutrients, etc.) can be studied to optimize fermentation performance. Yeast viability measurement is needed to identify higher ethanol-tolerant yeast strains, which may prolong the fermentation cycle and increase biofuel output. In addition, yeast concentration may be optimized to improve fermentation performance. Therefore, it is important to develop a simple method for concentration and viability measurement of fermenting yeast. In this work, we demonstrate an imaging cytometry method for concentration and viability measurements of yeast in corn mash directly from operating fermenters. It employs an automated cell counter, a dilution buffer, and staining solution from Nexcelom Bioscience to perform enumeration. The proposed method enables specific fluorescence detection of viable and nonviable yeasts, which can generate precise results for concentration and viability of yeast in corn mash. This method can provide an essential tool for research and development in the biofuel industry and may be incorporated into manufacturing to monitor yeast concentration and viability efficiently during the fermentation process.

  3. The Research Progress of Baker's Yeast%面包酵母研究进展

    Institute of Scientific and Technical Information of China (English)

    冯薇; 段绪果

    2008-01-01

    面包酵母是面包生产过程中最重要的微生物,在面包生产中起着关键作用.面包酵母菌种改良的研究主要集中在耐高糖的机制、麦芽糖的利用、低温适应性、蜜二糖的利用和乳糖的利用等方面.商品面包酵母生产的主要原料是甜菜糖蜜或甘蔗糖蜜,其发酵过程要求用补料的方法添加培养基,并要求适当的通风.

  4. Yeast redoxyendonuclease, a DNA repair enzyme similar to Escherichia coli endonuclease III

    Energy Technology Data Exchange (ETDEWEB)

    Gossett, J.; Lee, K.; Cunningham, R.P.; Doetsch, P.W.

    1988-04-05

    A DNA repair endonuclease (redoxyendonuclease) was isolated from bakers' yeast (Saccharomyces cerevisiae). The enzyme has been purified by a series of column chromatography steps and cleaves OsO/sub 4/-damaged, double-stranded DNA at sites of thymine glycol and heavily UV-irradiated DNA at sites of cytosine, thymine, and guanine photoproducts. The base specificity and mechanism of phosphodiester bond cleavage for the yeast redoxyendonuclease appear to be identical with those of Escherichia coli endonuclease III when thymine glycol containing, end-labeled DNA fragments of defined sequence are employed as substrates. Yeast redoxyendonuclease has an apparent molecular size of 38,000-42,000 daltons and is active in the absence of divalent metal cations. The identification of such an enzyme in yeast may be of value in the elucidation of the biochemical basis for radiation sensitivity in certain yeast mutants.

  5. Disturbance and Celebration of Josephine Baker in Copenhagen 1928

    DEFF Research Database (Denmark)

    Spanger, Marlene

    2015-01-01

    Marlene Spanger analyses reactions to the internationally recognised dancer and singer Josephine Baker (1906–1975), whose performances in Copenhagen gave rise to a heated emotional debate in Danish newspapers; these reactions mirror contemporary dominant religious, biological and colonial...... avant garde community and perceived as a threat to the ideal feminine form by the church. This contribution analyses how affective reactions are produced through complex formations of race, gender and sexuality, and enables us to acquire a nuanced understanding of whiteness in a Danish context....

  6. Mount Baker lahars and debris flows, ancient, modern, and future

    Science.gov (United States)

    Tucker, David S; Scott, Kevin M.; Grossman, Eric E.; Linneman, Scott

    2014-01-01

    The Middle Fork Nooksack River drains the southwestern slopes of the active Mount Baker stratovolcano in northwest Washington State. The river enters Bellingham Bay at a growing delta 98 km to the west. Various types of debris flows have descended the river, generated by volcano collapse or eruption (lahars), glacial outburst floods, and moraine landslides. Initial deposition of sediment during debris flows occurs on the order of minutes to a few hours. Long-lasting, down-valley transport of sediment, all the way to the delta, occurs over a period of decades, and affects fish habitat, flood risk, gravel mining, and drinking water.

  7. An algorithm for the Baker-Campbell-Hausdorff formula

    Science.gov (United States)

    Matone, Marco

    2015-05-01

    A simple algorithm, which exploits the associativity of the BCH formula, and that can be generalized by iteration, extends the remarkable simplification of the BakerCampbell-Hausdorff (BCH) formula, recently derived by Van-Brunt and Visser. We show that if [ X, Y] = uX + vY + cI, [ Y, Z] = wY + zZ + dI, and, consistently with the Jacobi identity, [ X, Z] = mX + nY + pZ + eI, then

  8. A generalization of the Baker-Hausdorff lemma

    Science.gov (United States)

    Mendaš, Istok P.; Popović, Duška B.

    2010-10-01

    Two operator identities involving a q-commutator, [A,B]≡AB+qBA, where A and B are two arbitrary (generally noncommuting) linear operators acting on the same linear space and q is a variable that commutes with these two operators, are formulated, proved and discussed. The first identity is a direct generalization of the Baker-Hausdorff lemma, whereas the second involves the time derivative of the exponential function of a time-dependant operator. It is indicated how these two identities can be used to good advantage to treat the Foldy-Wouthuysen transformation of the Dirac Hamiltonian for a particle in an external electromagnetic field.

  9. 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.

  10. Baker's asthma due to the enzyme xylanase -- a new occupational allergen.

    Science.gov (United States)

    Baur, X; Sander, I; Posch, A; Raulf-Heimsoth, M

    1998-12-01

    The asthmatic baker showed IgE-mediated sensitization to xylanase of Aspergillus niger used as a baking additive. Inhalative challenge with approximately 0.5 microg of the enzyme resulted in an immediate-type asthmatic reaction. This case, as well as a preliminary screening of symptomatic bakers, shows that xylanase is a further relevant type I-sensitizer in the baking industry.

  11. The Archives of the History of American Psychology: An Interview with David B. Baker.

    Science.gov (United States)

    Prieto, Loreto R.

    2001-01-01

    Presents an interview with David B. Baker, Director of the Archives of the History of American Psychology. Covers topics such as: Baker's interest in the history of psychology, his work at the Archives of the History of American Psychology, and recommendations for teachers when addressing history in non-history courses. (CMK)

  12. Recipe for Working Together: Gen. Colin Powell and the Baker's Dough Mural.

    Science.gov (United States)

    Herberholz, Barbara

    2001-01-01

    Describes the process for creating a baker's-dough mural that would become a permanent part of the community and relates a visit made to the Sacramento (California) Boys & Girls Club by General Colin Powell. Discusses Powell's part in creating the mural. Includes the steps for how to make a Baker's-dough mural. (CMK)

  13. Vandals in the Stacks? A Response to Nicholson Baker's Assault on Libraries.

    Science.gov (United States)

    Cox, Richard J.

    The book "Double Fold" is an investigation into what its author Nicholas Baker, a novelist and essayist, terms as a deception of research libraries and their maintenance of books and newspapers, their paper collections. This book is a response to Baker's writings, based on the author's perspective as an archivist. The first chapter introduces…

  14. Hydrothermal decomposition of yeast cells for production of proteins and amino acids.

    Science.gov (United States)

    Lamoolphak, Wiwat; Goto, Motonobu; Sasaki, Mitsuru; Suphantharika, Manop; Muangnapoh, Chirakarn; Prommuag, Chattip; Shotipruk, Artiwan

    2006-10-11

    This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 degrees C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 degrees C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 degrees C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products.

  15. 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).

  16. 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.

  17. Polynomial Decay of Correlations in the Generalized Baker's Transformation

    Science.gov (United States)

    Bose, Christopher; Murray, Rua

    2013-08-01

    We introduce a family of area preserving generalized baker's transformations acting on the unit square and having sharp polynomial rates of mixing for Holder data. The construction is geometric, relying on the graph of a single variable "cut function". Each baker's map B is non-uniformly hyperbolic and while the exact mixing rate depends on B, all polynomial rates can be attained. The analysis of mixing rates depends on building a suitable Young tower for an expanding factor. The mechanisms leading to a slow rate of correlation decay are especially transparent in our examples due to the simple geometry in the construction. For this reason we propose this class of maps as an excellent testing ground for new techniques for the analysis of decay of correlations in non-uniformly hyperbolic systems. Finally, some of our examples can be seen to be extensions of certain 1-D non-uniformly expanding maps that have appeared in the literature over the last twenty years thereby providing a unified treatment of these interesting and well-studied examples.

  18. Preparation of selenium yeasts I. Preparation of selenium-enriched Saccharomyces cerevisiae.

    Science.gov (United States)

    Suhajda, A; Hegóczki, J; Janzsó, B; Pais, I; Vereczkey, G

    2000-04-01

    Selenium (Se) is an essential micronutrient for human and animal organisms. Organic selenium complexes and selenium-containing amino acids are considered the most bioavailable. Under appropriate conditions yeasts are capable of accumulating large amounts of trace elements, such as selenium, and incorporating them into organic compounds. It has been found that introduction of water-soluble selenium salt as a component of the culture medium for yeasts produced by conventional batch processing results in a substantial amount of selenium being absorbed by the yeast. Using a culture medium supplemented with 30 microg/mL sodium-selenite added during the exponential growth phase results in selenium-accumulation in the range of 1200-1400 microg/g dried baker's yeast (Saccharomyces cerevisiae) measured by ICP-AES method. In our previous studies it was shown that higher amounts of sodium-selenite in the culture medium have a strong inhibitory effect on the growth of this yeast. As a consequence of variations in cultivation conditions we obtained selenium yeast with different inorganic selenium content. The most important parameters influencing incorporated forms of selenium are pH value and dissolved oxygen level in the culture medium, and depending on these the selenium consumption rate of the yeast. A 0.40-0.50 mg/g h-1 specific selenium consumption rate was found to be appropriate to obtain selenium-enriched bakers' yeast of a high quality. Under suitable conditions the undesirable inorganic selenium content of the yeast could be suppressed to as low as 5-6% at the expense, however, of approximately a 20% decrease in the final biomass.

  19. Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Palmqvist, E.; Grage, H.; Meinander, N.Q.; Hahn-Haegerdal, B. [Univ. of Lund (Sweden)

    1999-04-05

    The influence of the factors acetic acid, furfural, and p-hydroxybenzoic acid on the ethanol yield (Y{sub EtOH}) of Saccharomyces cerevisiae, bakers` yeast, S. cerevisiae ATCC 96581, and Candida shehatae NJ 23 was investigated using a 2{sup 3}-full factorial design with 3 centerpoints. The results indicated that acetic acid inhibited the fermentation by C. shehatae NJ 23 markedly more than by bakers` yeast, whereas no significant difference in tolerance towards the compounds was detected between the S. cerevisiae strains. Furfural and the lignin derived compound p-hydroxybenzoic acid did not affect any of the yeasts at the cell mass concentration used. The results indicated that the linear model was not adequate to describe the experimental data. Based on the results from the 2{sup 3}-full factorial experiment, an extended experiment was designed based on a central composite design to investigate the influence of the factors on the specific growth rate ({mu}), biomass yield (Y{sub x}), volumetric ethanol productivity (Q{sub EtOH}), and Y{sub EtOH}. Bakers` yeast was chosen in the extended experiment due to its better tolerance towards acetic acid, which makes it a more interesting organism for use in industrial fermentations of lignocellulosic hydrolysates.

  20. Identity of Baker's species described in the Oriental leafhopper genus Pythamus (Hemiptera: Cicadellidae) with description of a new genus.

    Science.gov (United States)

    Wei, Cong; Webb, Michael D; Zhang, Yalin

    2014-01-01

    Baker's (1915) species described in the Oriental leafhopper genus Pythamus Melichar are revised. One species, Pythamus melichari Baker 1915, is placed in a new genus, Pythochandra Wei & Webb, gen. n.. The four varieties of P. melichari described by Baker (1915, 1923) (borneensis, bilobatus, decoratus and singaporensis) are elevated to species level and placed in the new genus stat. n., comb. n.. All species are briefly described and a key is provided for their separation. Two other species, Pythamus productus Baker and P. decoratus Baker, known only from females, are retained in Pythamus pending further studies.

  1. Harvesting yeast (Saccharomyces cerevisiae) at different physiological phases significantly affects its functionality in bread dough fermentation.

    Science.gov (United States)

    Rezaei, Mohammad N; Dornez, Emmie; Jacobs, Pieter; Parsi, Anali; Verstrepen, Kevin J; Courtin, Christophe M

    2014-05-01

    Fermentation of sugars into CO2, ethanol and secondary metabolites by baker's yeast (Saccharomyces cerevisiae) during bread making leads to leavening of dough and changes in dough rheology. The aim of this study was to increase our understanding of the impact of yeast on dough related aspects by investigating the effect of harvesting yeast at seven different points of the growth profile on its fermentation performance, metabolite production, and the effect on critical dough fermentation parameters, such as gas retention potential. The yeast cells harvested during the diauxic shift and post-diauxic growth phase showed a higher fermentation rate and, consequently, higher maximum dough height than yeast cells harvested in the exponential or stationary growth phase. The results further demonstrate that the onset of CO2 loss from fermenting dough is correlated with the fermentation rate of yeast, but not with the amount of CO2 that accumulated up to the onset point. Analysis of the yeast metabolites produced in dough yielded a possible explanation for this observation, as they are produced in different levels depending on physiological phase and in concentrations that can influence dough matrix properties. Together, our results demonstrate a strong effect of yeast physiology at the time of harvest on subsequent dough fermentation performance, and hint at an important role of yeast metabolites on the subsequent gas holding capacity.

  2. [Occupational asthma--the case of bakers' asthma].

    Science.gov (United States)

    Bishara, Hasham; Carel, Rafael S

    2013-08-01

    Occupational asthma (OA) is the most common of all occupational lung diseases in industrialized countries and its prevalence has been rising steadily. It is estimated that occupational factors account for one out of six cases of adult asthmatic patients causing significant morbidity, disability and costs. Due to its high prevalence and substantial health and socio-economic impacts OA represents a significant public health concern. OA can be divided into allergic and non allergic asthma. Allergic OA is further divided into IgE mediated and non IgE mediated. Baker's asthma (BA), is the leading cause of IgE mediated OA caused by high molecular weight antgens in industrialized countries. Innovations in the baking industry during the last few decades have led to the introduction of new allergens inducing OA. OA is potentially preventable, through early diagnosis and exposure cessation interventions. Thus, clinicians should consider the occupational history in every adult patient presenting with newly diagnosed asthma.

  3. A new bioactive prenylated dihydroflavanoid from Dolichos tenuicaulis (Baker) Craib

    Institute of Scientific and Technical Information of China (English)

    Jin Yong Peng; Hai Yan Liu; Yan Qi; Xu Han; You Wei Xu; Li Na Xu; Qi Wei Xu

    2007-01-01

    A new prenylated dihydroflavonoid was obtained from the root of Dolichos tenuicaulis (Baker) Craib. The structure was elucidated as (2S)-5,2',6'-trihydroxy-3''', 8-di (γ, γ-dimethyl-allyl)-2''', 2'''-dimethylpyrano-[5''',6''':6,7]-2''''',4'''''-cyclohexadiene-1'''''-one-[2''''',3''''': 3',4']-flavanone, named dolichnin A, by spectroscopic methods including UV, IR, HR-EI-MS, 1D NMR and 2D NMR techniques, and subsequently, the anticancer activity of this compound to inhibit human cancer cells' growth including A549, BEL-7402, Hep-3B, SMMC7721, HT-29, MCF-7, SGC-7902, K562, A498 and PC3 cell lines by MTT method was evaluated in vitro.

  4. Hypersensitivity and chaos signatures in the quantum baker's maps

    CERN Document Server

    Scott, A J; Caves, C M; Schack, R; Brun, Todd A.; Caves, Carlton M.; Schack, Ruediger

    2006-01-01

    Classical chaotic systems are distinguished by their sensitive dependence on initial conditions. The absence of this property in quantum systems has lead to a number of different criteria being proposed for quantum chaos, including linear growth of entropy, exponential decay of fidelity, and hypersensitivity to perturbation. All of these accurately predict chaos in the classical limit, but it is not clear that they behave the same far from the classical realm. We investigate the dynamics of a family of quantizations of the baker's map, which range from a highly entangling unitary transformation to an essentially trivial shift map. Linear entropy growth and fidelity decay are exhibited by this entire family of maps, but hypersensitivity distinguishes between the simple dynamics of the trivial shift map and the more complicated dynamics of the other quantizations. This is supported by an analytical argument for short times and numerical evidence at later times.

  5. Supermarket baker's asthma: how accurate is routine health surveillance?

    Science.gov (United States)

    Brant, A; Nightingale, S; Berriman, J; Sharp, C; Welch, J; Newman, T; Cullinan, P

    2005-01-01

    Background: Regular health surveillance is commonly recommended for workers exposed to occupational antigens but little is known about how effective it is in identifying cases. Aims: To report one large company's surveillance and compare its findings with those of a standard cross-sectional survey in the same workforce. Methods: A supermarket company with 324 in-store bakeries producing bread from raw ingredients conducted a three-stage health surveillance programme in around 3000 bakery employees. The first stage involved the administration of a simple respiratory questionnaire. If chest symptoms were present a second questionnaire focusing on their work relationship was administered. If positive a blood sample was requested for the measurement of specific IgE to flour and fungal α-amylase. The results were compared to an independent cross-sectional survey of employees in 20 of the company's stores. Results: Two hundred and ninety nine (92%) of the company's bakeries took part in surveillance. The overall employee response for the first stage was 77%; a quarter of those with respiratory symptoms reported that they were work related. Seventy four (61%) of those with work related chest symptoms had a measurement of specific IgE to either flour or fungal α-amylase, of whom 30 (41%) had a positive result. Surveillance estimated that 1% of bakery employees (1% bakers, 2% managers, 0.6% confectioners) had work related symptoms with specific IgE. This compared with 4% (7.5% bakers, 3.3% managers, 0% confectioners) in the cross-sectional survey (n = 166, 93% response). Conclusion: Comparison with a standard cross-sectional survey suggests that routine surveillance can underestimate the workplace burden of disease. The reasons may include technical or resource issues and uncertainties over confidentiality or the perceived consequences of participation. More research needs to be done looking into the design and efficacy of surveillance in occupational asthma. PMID

  6. Origin of the Yeast Whole-Genome Duplication.

    Directory of Open Access Journals (Sweden)

    Kenneth H Wolfe

    2015-08-01

    Full Text Available Whole-genome duplications (WGDs are rare evolutionary events with profound consequences. They double an organism's genetic content, immediately creating a reproductive barrier between it and its ancestors and providing raw material for the divergence of gene functions between paralogs. Almost all eukaryotic genome sequences bear evidence of ancient WGDs, but the causes of these events and the timing of intermediate steps have been difficult to discern. One of the best-characterized WGDs occurred in the lineage leading to the baker's yeast Saccharomyces cerevisiae. Marcet-Houben and Gabaldón now show that, rather than simply doubling the DNA of a single ancestor, the yeast WGD likely involved mating between two different ancestral species followed by a doubling of the genome to restore fertility.

  7. 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.

  8. 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.

  9. Aerial Photography and Imagery, Ortho-Corrected - 2011 Digital Orthophotos - Baker County

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This dataset is a collection of GeoTIFF natural color orthophotos covering Baker, Bradford, and Union counties within Florida. An orthophoto is remotely sensed image...

  10. CRED REA Fish Team Belt Transect Survey at Baker, Pacific Remote Island Areas, 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 9 sites at Baker in the Pacific...

  11. CRED REA Fish Team Stationary Point Count Surveys at Baker, Pacific Remote Island Areas in 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments (REA) conducted at 4 sites around Baker in the...

  12. CRED REA Fish Team Belt Transect Survey at Baker, Pacific Remote Island Areas in 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Belt transects along 3 consecutively-placed, 25m transect lines were surveyed as part of Rapid Ecological Assessments conducted at 4 sites at Baker in the Pacific...

  13. CRED REA Algal Assessments at Baker Island, Pacific Remote Island Areas in 2008

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twelve quadrats were sampled along 2 consecutively-placed, 25m transect lines, as part of Rapid Ecological Assessments, conducted at 1 site at Baker in the Pacific...

  14. Baker-Akhiezer function as iterated residue and Selberg-type integral

    CERN Document Server

    Felder, Giovanni

    2008-01-01

    A simple integral formula as an iterated residue is presented for the Baker-Akhiezer function related to $A_n$ type root system both in the rational and trigonometric cases. We present also a formula for the Baker-Akhiezer function as a Selberg-type integral and generalise it to the deformed $A_{n,1}$-case. These formulas can be interpreted as new cases of explicit evaluation of Selberg-type integrals.

  15. 113Cd-NMR investigation of a cadmium-substituted copper, zinc-containing superoxide dismutase from yeast

    DEFF Research Database (Denmark)

    Kofod, Pauli; Bauer, Rogert; Danielsen, Eva

    1991-01-01

    113Cd nuclear magnetic resonance spectroscopy has been used to investigate the metal binding sites of cadmium-substituted copper,zinc-containing superoxide dismutase from baker's yeast. NMR signals were obtained for 113Cd(II) at the Cu site as well as for 113Cd(II) at the Zn site. The two subunits...... an explanation for the discrepancy in the literature regarding 113Cd-NMR investigations of bovine superoxide dismutase....

  16. Interactions between Drosophila and its natural yeast symbionts-Is Saccharomyces cerevisiae a good model for studying the fly-yeast relationship?

    Science.gov (United States)

    Hoang, Don; Kopp, Artyom; Chandler, James Angus

    2015-01-01

    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 preference of D

  17. 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.

  18. Vernonia condensata Baker (Asteraceae: A Promising Source of Antioxidants

    Directory of Open Access Journals (Sweden)

    Jucélia Barbosa da Silva

    2013-01-01

    Full Text Available The present study evaluated the antioxidant potential of Vernonia condensata Baker (Asteraceae. Dried and powdered leaves were exhaustively extracted with ethanol by static maceration followed by partition to obtain the hexane, dichloromethane, ethyl acetate, and butanol fractions. Total phenols and flavonoids contents were determined through spectrophotometry and flavonoids were identified by HPLC-DAD system. The antioxidant activity was assessed by DPPH radical scavenging activity, TLC-bioautography, reducing power of Fe+3, phosphomolybdenum, and TBA assays. The total phenolic content and total flavonoids ranged from 0.19 to 23.11 g/100 g and from 0.13 to 4.10 g/100 g, respectively. The flavonoids apigenin and luteolin were identified in the ethyl acetate fraction. The IC50 of DPPH assay varied from 4.28 to 75.10 µg/mL and TLC-bioautography detected the antioxidant compounds. The reducing power of Fe+3 was 19.98 to 336.48 μg/mL, while the reaction with phosphomolybdenum ranged from 13.54% to 32.63% and 56.02% to 135.00% considering ascorbic acid and rutin as reference, respectively. At 30 mg/mL, the ethanolic extract and fractions revealed significant effect against lipid peroxidation. All these data sustain that V. condensata is an important and promising source of bioactive substances with antioxidant activity.

  19. Free radical scavenging potential of Chlorophytum tuberosum Baker.

    Science.gov (United States)

    Narasimhan, Sreevidya; Govindarajan, Raghavan; Vijayakumar, Madhavan; Mehrotra, Shanta

    2006-04-06

    Chlorophytum tuberosum Baker commonly referred as 'Musli' has been widely used as a potent 'Rasayana' drug in 'Ayurveda' as a rejuvenator and tonic. Antioxidant potential of Chlorophytum tuberosum has been investigated for their ability to scavenge 1,1,diphenyl picryl hydrazyl (DPPH), nitric oxide radical along with their capacity to reduce lipid peroxidation in rat liver homogenate, chelation of ferrous ion, radical scavenging potential using chemiluminescence and their total antioxidant capacity. Sugar, starch, protein, and Vitamin C content were estimated spectrophotometrically along with the percentages of the individual amino acids by HPLC and individual sugars by using HPTLC as standardization tool. The extract has been found to possess antioxidant activity in all the models tested as evident by IC50 values being 225.31, 888.44, 809.22 and 422.97 microg/ml for scavenging of DPPH, nitric oxide, lipid peroxidation and ferry bi-pyridyl complex, respectively, along with a integral anitoxidant activity of 2.986 nmol ascorbic acid/g equivalents in photochemiluminescence assay.

  20. A vibrating membrane bioreactor operated at supra- and sub-critical flux: Influence of extracellular polymeric substances from yeast cells

    DEFF Research Database (Denmark)

    Beier, Søren Prip; Jonsson, Gunnar Eigil

    2007-01-01

    A vibrating membrane bioreactor, in which the fouling problems are reduced by vibrating a hollow fiber membrane module, has been tested in constant flux microfiltration above (supra-critical) and below (sub-critical) an experimentally determined critical flux. Suspensions of bakers yeast cells were...... chosen as filtration medium (dry weight 4 g/l). The influence of extracellular polymeric substances (EPS) from the yeast cells is evaluated by UV absorbance measurements of the bulk supernatant during filtration. The critical flux seems to be an interval or a relative value rather than an absolute value...

  1. 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.

  2. 'Yeast mail': a novel Saccharomyces application (NSA) to encrypt messages.

    Science.gov (United States)

    Rosemeyer, Helmut; Paululat, Achim; Heinisch, Jürgen J

    2014-09-01

    The universal genetic code is used by all life forms to encode biological information. It can also be used to encrypt semantic messages and convey them within organisms without anyone but the sender and recipient knowing, i.e., as a means of steganography. Several theoretical, but comparatively few experimental, approaches have been dedicated to this subject, so far. Here, we describe an experimental system to stably integrate encrypted messages within the yeast genome using a polymerase chain reaction (PCR)-based, one-step homologous recombination system. Thus, DNA sequences encoding alphabetical and/or numerical information will be inherited by yeast propagation and can be sent in the form of dried yeast. Moreover, due to the availability of triple shuttle vectors, Saccharomyces cerevisiae can also be used as an intermediate construction device for transfer of information to either Drosophila or mammalian cells as steganographic containers. Besides its classical use in alcoholic fermentation and its modern use for heterologous gene expression, we here show that baker's yeast can thus be employed in a novel Saccharomyces application (NSA) as a simple steganographic container to hide and convey messages.

  3. 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.

  4. The fermentation of lignocellulose hydrolysates with xylose isomerases and yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Linden, T.

    1992-01-01

    Untreated spent sulphite liquor (SSL) was fermented with Canida tropicalis, Pichia stipitis, Pachysolen tannophilus, Schizosaccharomyces pombe, Saccharomyces cerevisiae and a co-culture of P. Tannophilus and A. cerevisiae, in the presence of xylose isomerases and 4.6 mM azide. The highest yield of ethanol, 0.41 g/g total sugar was obtained with S. cerevisiae, C. tropicalis, and P. tannophilus produced considerble amounts of polyoles, mainly xylitol. With P. stipitis sugar uptake was rapidly inhibited in untreated SSL. The presence of azide contributed to the yield by about 0.04. The fermentation of hydrogen fluoride-pretreated and acid-hydrolysed wheat straw with S. cerevisiae, xylose isomerase, and azide gave a yield of 0.40 g ethanol/g total sugar. In this substrate the xylose utilisation was 84% compared with 51% in SSL. In the concentration range appropriate for enzymatic xylose isomerization, xylulose was measured in a lignocellulose hydrolysate using HPLC with two hydrogen loaded ion exchange columns in series. SSL was used as a model for lignocellulose hydrolysates. The enzymatic isomerization of xylose to xylulose was followed directly in SSL, providing a method for the direct determination of xylose isomerase activity in lignocellulose hydrolysates. Three different xylose isomerase preparations of L. brevis whole cells were compared with a commercial enzyme preparation Maxazyme GI-immob., with respect to activity and stability. From a continuous SSL fermentation plant, two species of yeasts were isolated, S. cerevisiae and Pichia membranaefaciens. One of the isolates of S. cerevisiae, no. 3 was heavily flocculating. Without acetic acid present, both bakers' yeast and isolate no. 3 showed catabolite repression and fermented glucose and galactose sequentially. Galactose fermentation with bakers' yeast was strongly inhibited by acetic acid at pH values below 6. Isolate no. 3 fermented galactose, glucose and mannose, in the presence of acetic acid

  5. The fermentation of lignocellulose hydrolysates with xylose isomerases and yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Linden, T.

    1992-09-01

    Untreated spent sulphite liquor (SSL) was fermented with Canida tropicalis, Pichia stipitis, Pachysolen tannophilus, Schizosaccharomyces pombe, Saccharomyces cerevisiae and a co-culture of P. Tannophilus and A. cerevisiae, in the presence of xylose isomerases and 4.6 mM azide. The highest yield of ethanol, 0.41 g/g total sugar was obtained with S. cerevisiae, C. tropicalis, and P. tannophilus produced considerble amounts of polyoles, mainly xylitol. With P. stipitis sugar uptake was rapidly inhibited in untreated SSL. The presence of azide contributed to the yield by about 0.04. The fermentation of hydrogen fluoride-pretreated and acid-hydrolysed wheat straw with S. cerevisiae, xylose isomerase, and azide gave a yield of 0.40 g ethanol/g total sugar. In this substrate the xylose utilisation was 84% compared with 51% in SSL. In the concentration range appropriate for enzymatic xylose isomerization, xylulose was measured in a lignocellulose hydrolysate using HPLC with two hydrogen loaded ion exchange columns in series. SSL was used as a model for lignocellulose hydrolysates. The enzymatic isomerization of xylose to xylulose was followed directly in SSL, providing a method for the direct determination of xylose isomerase activity in lignocellulose hydrolysates. Three different xylose isomerase preparations of L. brevis whole cells were compared with a commercial enzyme preparation Maxazyme GI-immob., with respect to activity and stability. From a continuous SSL fermentation plant, two species of yeasts were isolated, S. cerevisiae and Pichia membranaefaciens. One of the isolates of S. cerevisiae, no. 3 was heavily flocculating. Without acetic acid present, both bakers` yeast and isolate no. 3 showed catabolite repression and fermented glucose and galactose sequentially. Galactose fermentation with bakers` yeast was strongly inhibited by acetic acid at pH values below 6. Isolate no. 3 fermented galactose, glucose and mannose, in the presence of acetic acid even at pH.

  6. Non-Genetic Engineering Approaches for Isolating and Generating Novel Yeasts for Industrial Applications

    Science.gov (United States)

    Chambers, P. J.; Bellon, J. R.; Schmidt, S. A.; Varela, C.; Pretorius, I. S.

    Generating novel yeast strains for industrial applications should be quite straightforward; after all, research into the genetics, biochemistry and physiology of Baker's Yeast, Saccharomyces cerevisiae, has paved the way for many advances in the modern biological sciences. We probably know more about this humble eukaryote than any other, and it is the most tractable of organisms for manipulation using modern genetic engineering approaches. In many countries, however, there are restrictions on the use of genetically-modified organisms (GMOs), particularly in foods and beverages, and the level of consumer acceptance of GMOs is, at best, variable. Thus, many researchers working with industrial yeasts use genetic engineering techniques primarily as research tools, and strain development continues to rely on non-GM technologies. This chapter explores the non-GM tools and strategies available to such researchers.

  7. Obituary: Norman Hodgson Baker, Jr., 1931-2005

    Science.gov (United States)

    Helfand, David J.

    2005-12-01

    Norman H. Baker, a key contributor to the foundation of modern stellar pulsation theory and former editor of the "Astronomical Journal", died on 11 October 2005 in Watertown, New York near his beloved summer home in Natural Bridge. He succumbed to complications of Waldenstrom's macroglobulinemia, a bone marrow lymphoma that he had successfully surmounted for twenty-two years. Norm, as he was known to all, was born 23 October 1931 in Fergus Falls, Minnesota to Norman Hodgson and Jeannette (née Lieber) Baker. He attended the University of Minnesota where he met the first of many lifelong astronomical friends, Bill Erickson. He received his BA in 1952. He went on to do his PhD, "Radiation from Particle Interactions which Create Current," at Cornell University under Phil Morrison. He then moved to a postdoctoral position at the Max Planck Institut für Physik und Astrophysik in München with the intent of pursuing his work in plasma physics with Ludwig Biermann and Arnulf Schlüter. However, Rudolf (Rudi) Kippenhan snatched him away to pursue what became his lifelong interest, stellar physics. This was the dawn of the era in which electronic computers were becoming practical for scientific calculations, and Norm immediately adopted this new tool. Indeed, he remained at the forefront of computing technology throughout his life: He was certainly the first member of the Astronomy Department at Columbia to buy a Mac, and was undoubtedly one of the few emeritus professors in the world known by all the administrative staff as the first person to turn to when stumped by a computer problem. Following his first paper with Kippenhan on stellar rotation, Norm turned his attention to stellar pulsations, a topic he would pursue throughout his career. His 1962 paper in "Zeitschrift für Astrophysik" on pulsational models of Cepheids (Baker and Kippenhan 1962, 54, 155) is a classic in the field. The first figure displays the three dimensional model of the atmospheric absorption

  8. 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

  9. Component-resolved diagnosis of baker's allergy based on specific IgE to recombinant wheat flour proteins

    NARCIS (Netherlands)

    Sander, Ingrid; Rihs, Hans-Peter; Doekes, Gert; Quirce, Santiago; Krop, Esmeralda; Rozynek, Peter; van Kampen, Vera; Merget, Rolf; Meurer, Ursula; Brüning, Thomas; Raulf, Monika

    2015-01-01

    BACKGROUND: Sensitization to wheat flour plays an important role in the development and diagnosis of baker's asthma. OBJECTIVES: We evaluated wheat allergen components as sensitizers for bakers with work-related complaints, with consideration of cross-reactivity to grass pollen. METHODS: Nineteen re

  10. 77 FR 12002 - Mount Baker-Snoqualmie National Forest Site-Specific Invasive Plant Treatment Project and Forest...

    Science.gov (United States)

    2012-02-28

    ... Forest Service Mount Baker-Snoqualmie National Forest Site-Specific Invasive Plant Treatment Project and... invasive plants on the Mt. Baker-Snoqualmie National Forest. The current Forest-wide treatment approach pre... adding management direction for invasive plants and authorizing new tools to increase treatment...

  11. Reconstructing streamflow variation of the Baker River from tree-rings in Northern Patagonia since 1765

    Science.gov (United States)

    Lara, Antonio; Bahamondez, Alejandra; González-Reyes, Alvaro; Muñoz, Ariel A.; Cuq, Emilio; Ruiz-Gómez, Carolina

    2015-10-01

    The understanding of the long-term variation of large rivers streamflow with a high economic and social relevance is necessary in order to improve the planning and management of water resources in different regions of the world. The Baker River has the highest mean discharge of those draining both slopes of the Andes South of 20°S and it is among the six rivers with the highest mean streamflow in the Pacific domain of South America (1100 m3 s-1 at its outlet). It drains an international basin of 29,000 km2 shared by Chile and Argentina and has a high ecologic and economic value including conservation, tourism, recreational fishing, and projected hydropower. This study reconstructs the austral summer - early fall (January-April) streamflow for the Baker River from Nothofagus pumilio tree-rings for the period 1765-2004. Summer streamflow represents 45.2% of the annual discharge. The regression model for the period (1961-2004) explains 54% of the variance of the Baker River streamflow (R2adj = 0.54). The most significant temporal pattern in the record is the sustained decline since the 1980s (τ = -0.633, p = 1.0144 ∗ 10-5 for the 1985-2004 period), which is unprecedented since 1765. The Correlation of the Baker streamflow with the November-April observed Southern Annular Mode (SAM) is significant (1961-2004, r = -0.55, p development of new tree-ring reconstructions to increase the geographic range and to cover the last 1000 or more years using long-lived species (e.g. Fitzroya cupressoides and Pilgerodendron uviferum). Expanding the network and quality of instrumental weather, streamflow and other monitoring stations as well as the study and modeling of the complex hydrological processes in the Baker basin are necessary. This should be the basis for planning, policy design and decision making regarding water resources in the Baker basin.

  12. Opto-digital spectrum encryption by using Baker mapping and gyrator transform

    Science.gov (United States)

    Chen, Hang; Zhao, Jiguang; Liu, Zhengjun; Du, Xiaoping

    2015-03-01

    A concept of spectrum information hidden technology is proposed in this paper. We present an optical encryption algorithm for hiding both the spatial and spectrum information by using the Baker mapping in gyrator transform domains. The Baker mapping is introduced for scrambling the every single band of the hyperspectral image before adding the random phase functions. Subsequently, three thin cylinder lenses are controlled by PC for implementing the gyrator transform. The amplitude and phase information in the output plane can be regarded as the encrypted information and main key. Some numerical simulations are made to test the validity and capability of the proposed encryption algorithm.

  13. Opto-digital image encryption by using Baker mapping and 1-D fractional Fourier transform

    Science.gov (United States)

    Liu, Zhengjun; Li, She; Liu, Wei; Liu, Shutian

    2013-03-01

    We present an optical encryption method based on the Baker mapping in one-dimensional fractional Fourier transform (1D FrFT) domains. A thin cylinder lens is controlled by computer for implementing 1D FrFT at horizontal direction or vertical direction. The Baker mapping is introduced to scramble the amplitude distribution of complex function. The amplitude and phase of the output of encryption system are regarded as encrypted image and key. Numerical simulation has been performed for testing the validity of this encryption scheme.

  14. Ultrasound guided percutaneous treatment and follow-up of Baker's cyst in knee osteoarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Koeroglu, Mert, E-mail: mertkoroglu@hotmail.com [Antalya Education and Research Hospital, Department of Radiology, Antalya (Turkey); Call Latin-Small-Letter-Dotless-I oglu, Mehmet, E-mail: mehmetcallioglu@hotmail.com [Sueleyman Demirel University, Faculty of Medicine, Department of Radiology, Isparta (Turkey); Eris, Hueseyin Naim, E-mail: drhneris@hotmail.com [Sueleyman Demirel University, Faculty of Medicine, Department of Radiology, Isparta (Turkey); Kayan, Mustafa, E-mail: drkayan32@hotmail.com [Sueleyman Demirel University, Faculty of Medicine, Department of Radiology, Isparta (Turkey); Cetin, Meltem, E-mail: meltemcetin2011@yahoo.com [Sueleyman Demirel University, Faculty of Medicine, Department of Radiology, Isparta (Turkey); Yener, Mahmut, E-mail: bahtiyaryener@yahoo.com [Sueleyman Demirel University, Faculty of Medicine, Department of Physical Medicine and Rehabilitation, Isparta (Turkey); Guerses, Cemil, E-mail: cemilgurses@gmail.com [Antalya Education and Research Hospital, Department of Radiology, Antalya (Turkey); Erol, Bekir, E-mail: mertkoroglu@hotmail.com [Antalya Education and Research Hospital, Department of Radiology, Antalya (Turkey); Tuerkbey, Bar Latin-Small-Letter-Dotless-I s, E-mail: bturkbey@yahoo.com [Hacettepe University, Faculty of Medicine, Department of Radiology, Ankara (Turkey); Parlak, Ayse Eda, E-mail: drteda@yahoo.com [Antalya Education and Research Hospital, Department of Radiology, Antalya (Turkey); Akhan, Okan, E-mail: akhano@tr.net [Hacettepe University, Faculty of Medicine, Department of Radiology, Ankara (Turkey)

    2012-11-15

    Objective: Purpose of this study is to assess sonographic changes and clinical response in different subgroups of Baker's cyst patients with knee osteoarthritis after a single session of ultrasound-guided percutaneous aspiration and corticosteroid injection. Materials and methods: Thirty-two knee osteoarthritis patients (46-85 years, mean 58.97 {+-} 9.88) with symptomatic Baker's cyst diagnosed at ultrasonography were included in the study. To determine the grade of the symptoms, Visual Analogue Scale was applied. The patients were grouped in two, as simple (n = 24) and complex (n = 8) Baker's cyst. Thirty-two ultrasound-guided cyst aspirations concomitant 1 ml betamethasone injection (24 simple, 8 complex subgroups) were performed. Patients were followed clinically as well as via ultrasonography for 6 months after procedures. Results: A significant decrease in volume of the Baker's cysts after percutaneous treatment was accompanied by a significant clinical improvement. Moreover, the volume reduction of Baker's cyst after the treatment was significantly correlated with the clinical improvement (Pearson correlation coefficient = 0.542, p = 0.001). All 6 Baker's cysts relapsed at ultrasonography were complex type. Furthermore, a comparison of patients with simple Baker's cysts and those with complex Baker's cysts demonstrated no significant change in Visual Analogue Scale scores between two groups (p = 0.061, Mann-Whitney U). No complications (minor or major) occurred secondary to percutaneous treatment. Conclusion: Baker's cysts can be grouped as simple and complex groups via ultrasonography prior to the treatment. Cyst aspiration with ultrasound-guided corticosteroid injection yields clinical improvement and cyst volume reduction in all subgroups of patients with Baker's cyst secondary to knee osteoarthritis.

  15. Yeast studies reveal moonlighting functions of the ancient actin cytoskeleton

    Science.gov (United States)

    Sattlegger, Evelyn; Chernova, Tatiana A.; Gogoi, Neeku M.; Pillai, Indu V.; Chernoff, Yury O.; Munn, Alan L.

    2014-01-01

    Classic functions of the actin cytoskeleton include control of cell size and shape and the internal organisation of cells. These functions are manifest in cellular processes of fundamental importance throughout biology such as the generation of cell polarity, cell migration, cell adhesion and cell division. However, studies in the unicellular model eukaryote Saccharomyces cerevisiae (Baker's yeast) are giving insights into other functions in which the actin cytoskeleton plays a critical role. These include endocytosis, control of protein translation and determination of protein 3-dimensional shape (especially conversion of normal cellular proteins into prions). Here we present a concise overview of these new "moonlighting" roles for the actin cytoskeleton and how some of these roles might lie at the heart of important molecular switches. This is an exciting time for researchers interested in the actin cytoskeleton. We show here how studies of actin are leading us into many new and exciting realms at the interface of genetics, biochemistry and cell biology. While many of the pioneering studies have been conducted using yeast, the conservation of the actin cytoskeleton and its component proteins throughout eukaryotes suggests that these new roles for the actin cytoskeleton may not be restricted to yeast cells but rather may reflect new roles for the actin cytoskeleton of all eukaryotes. PMID:25138357

  16. Resistance of yeasts to weak organic acid food preservatives.

    Science.gov (United States)

    Piper, Peter W

    2011-01-01

    Carboxylate weak acids are invaluable for large-scale food and beverage preservation. However, in response to safety concerns, there is now desire to reduce the use of these additives. The resistance to these compounds displayed by spoilage yeasts and fungi is a major reason why these preservatives often have to be used in millimolar levels. This chapter summarizes the mechanisms whereby yeasts are rendered resistant to acetate, propionate, sorbate, and benzoate. In baker's yeast (Saccharomyces cerevisiae), resistance to high acetic acid is acquired partly by loss of the plasma membrane aquaglyceroporin that facilitates the passive diffusional entry of undissociated acid into cells (Fps1), and partly through a transcriptional response mediated by the transcription factor Haa1. Other carboxylate preservatives are too large to enter cells through the Fps1 channel but instead penetrate at appreciable rates by passive diffusion across the plasma membrane. In Saccharomyces and Candida albicans though not, it seems, in the Zygosaccharomyces, resistance to the latter acids involves activation of the War1 transcription factor, which in turn generates strong induction of a specific plasma membrane ATP-binding cassette transporter (Pdr12). The latter actively pumps the preservative anion from the cell. Other contributors to weak acid resistance include enzymes that allow preservative degradation, members of the Tpo family of major facilitator superfamily transporters, and changes to the cell envelope that minimize the diffusional entry of the preservative into the cell.

  17. Rapid toxicity testing based on yeast respiratory activity

    Energy Technology Data Exchange (ETDEWEB)

    Haubenstricker, M.E. (Environmental Protection Agency, Ann Arbor, MI (USA)); Meier, P.G.; Mancy, K.H. (Univ. of Michigan, Ann Arbor (USA)); Brabec, M.J. (Eastern Michigan Univ., Ypsilanti (USA))

    1990-05-01

    Rapid and economical techniques are needed to determine the effects of environmental contaminants. At present, the main methods to assess the impact of pollutants are based on chemical analysis of the samples. Invertebrate and vertebrate exposures have been used over the last two decades in assessing acute and chronic toxicities. However, these tests are labor intensive and require several days to complete. An alternative to whole organism exposure is to determine toxic effects in monocellular systems. Another approach for assessing toxicity is to monitor sensitive, nonspecific, subcellular target sites such as mitochondria. Changes in mitochondrial function which could indicate a toxic effect can be demonstrated readily after addition of a foreign substance. In initial assessments of various chemicals, rat liver mitochondria (RLM) were evaluated as a biological sensor of toxicity. False toxicity assessments will result if these ions are present even though they are generally considered nontoxic. Because of these disadvantages, an alternative mitochondrial system, such as found in bakers yeast, was evaluated.

  18. Baker Island Site 5P 1/24/2004 12-13M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 12 and 13 meters along a permanent transect.

  19. Oscuros estados de deseo: Josephine Baker, identidad y el cuerpo sexual negro

    OpenAIRE

    Romero Ruiz, María Isabel

    2012-01-01

    La puesta en escena de josephine baker del cuerpo de color femenino en los escenarios de parís en los años 20 y 30 es un ejemplo de la comodificación de la sexualidad femenina. Tiene su precedente en el siglo xix en saartjie baartman, conocida como la ven

  20. Baker Island Site 11P 1/24/2004 1-2M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 11P (00 11.941N, 176 29.078W), between 1 and 2 meters along a permanent transect.

  1. Exact Baker-Campbell-Hausdorff formula for the contact Heisenberg algebra

    CERN Document Server

    Bravetti, Alessandro; Tapias, Diego

    2016-01-01

    In this work we introduce the contact Heisenberg algebra as the Lie algebra of linear functions over a contact manifold and we give the exact expression of its corresponding Baker-Campbell-Hausdorff formula. We argue that this result is relevant to the quantization of contact systems.

  2. National Apprenticeship and Training Standards for Associated Retail Bakers of America.

    Science.gov (United States)

    Associated Retail Bakers of America, Chicago, IL.

    The document presents systematic standards (adopted by the Associated Retail Bakers of America in accordance with the basic standards recommended by the Bureau of Apprenticeship and Training of the U.S. Department of Labor) to be used in the apprenticeship and training programs of the baking industry. Included is the following information: (1)…

  3. Baker Island Site 5P 1/24/2004 49-50M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 49 and 50 meters along a permanent transect.

  4. Baker Island Site 5P 3/19/2000 34-35M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 34 and 35 meters along a permanent transect.

  5. Baker Island Site 16P 1/30/2002 7-8M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 16P (00 11 698N, 176 27.753W), between 7 and 8 meters along a permanent transect.

  6. Baker Island Site 5P 1/29/2002 18-19M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 18 and 19 meters along a permanent transect.

  7. Baker Island Site 5P 1/24/2004 33-34M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 33 and 34 meters along a permanent transect.

  8. Chicks in Charge: Andrea Baker & Amy Daniels--Airport High School Media Center, Columbia, SC

    Science.gov (United States)

    Library Journal, 2004

    2004-01-01

    This article briefly discusses two librarians exploration of Linux. Andrea Baker and Amy Daniels were tired of telling their students that new technology items were not in the budget. They explored Linux, which is a program that recycles older computers, installs free operating systems and free software.

  9. Baker Island Site 5P 3/19/2000 29-30M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 29 and 30 meters along a permanent transect.

  10. Baker Island Site 11P 1/24/2004 16-17M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 11P (00 11.941N, 176 29.078W), between 16 and 17 meters along a permanent transect.

  11. Baker Island Site 11P 2/10/2001 24-25M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 11P (00 11.941N, 176 29.078W), between 24 and 25 meters along a permanent transect.

  12. Baker Island Site 5P 2/9/2001 80-81M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (0 11.781N, 176 29.176W), between 80 and 81 meters along a permanent transect.

  13. Baker Island Site 16P 1/23/2004 45-46M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 16P (00 11 698N, 176 27.753W), between 45 and 46 meters along a permanent transect.

  14. Climate Driven Retreat of Mount Baker Glaciers and Changing Water Resources

    Directory of Open Access Journals (Sweden)

    Tristram Irvine-Fynn

    2016-08-01

    Full Text Available Reviewed: Climate Driven Retreat of Mount Baker Glaciers and Changing Water Resources By Mauri Pelto. Cham, Switzerland: Springer, 2015. x + 107 pp. Softcover: US$ 54.99, ISBN 978-3-319-22604-0. E-book: US$ 39.99, ISBN 978-3-319-22605-7.

  15. Baker Island Site 11P 2/10/2001 29-30M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 11P (00 11.941N, 176 29.078W), between 29 and 30 meters along a permanent transect.

  16. The natural extensions of β-transformations which generalize baker's transformations

    Science.gov (United States)

    Kwon, Do Yong

    2009-02-01

    We consider the natural extensions of β-transformations. For some specific β, the extensions can be viewed as generalized baker's transformations, i.e. they flatten and stretch and then cut and stack a two-dimensional domain. This paper characterizes such β and studies their properties.

  17. Baker Island Site 5P 3/19/2000 87-88M

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — One-meter-square (1 meter x 1 meter) benthic substrate at Baker Island, site 5P (00 11.781N, 176 29.176W), between 87 and 88 meters along a permanent transect.

  18. Realizing the quantum baker's map on a 3-qubit NMR quantum computer

    CERN Document Server

    Brun, T A; Brun, Todd A.; Schack, Ruediger

    1999-01-01

    By numerically simulating an implementation of the quantum baker's map on a 3-qubit NMR quantum computer based on the molecule trichloroethylene, we demonstrate the feasibility of quantum chaos experiments on present-day quantum computers. We give detailed descriptions of proposed experiments that investigate (a) the rate of entropy increase due to decoherence and (b) the phenomenon of hypersensitivity to perturbation.

  19. A set of amino acids found to occur more frequently in human and fly than in plant and yeast proteomes consists of non-essential amino acids

    OpenAIRE

    2007-01-01

    We investigated the hypothesis that essential amino acids are being replaced in proteins by non-essential amino acids.We compared the amino acid composition in human, worm and fly proteomes, organisms that cannot synthesize all amino acids, with the amino acids of the proteomes of plant, bakers yeast and budding yeast, which are capable of synthesizing them. The analysis covered 460,737 proteins (212,197,907 amino acids). The data suggest a bias towards the usage of non-essential ami...

  20. Erisipelóide de Baker-Rosenbach

    Directory of Open Access Journals (Sweden)

    Aureo Guimarães de Macedo

    1970-10-01

    Full Text Available O erisipelóide de Baker-Rosenbach, embora assinalado no Brasil há 23, anos, por Sebastião Sampaio, seguido de nove casos estudados em 1951 por Lacaz e Ancona Lopes, não tem sido motivo de publicações posteriores. O A. teve ocasião de estudar seis casos, senão que três foram motivo de trabalho anterior e foram observados em 1953. Os três restantes, um de 1965 e dois de 1967, são aqui relatados. Assinala o A. a ubiquidade do germe, o Erysipelotrix rhusiopathiae e a variedade de condições em que o homem pode infectar-se, especialmente no exercício de determinadas profissões, o que dá à doença, caráter típico de doença profissional. São os operários de fábricas de botões ou em geral os que lidam com ossos, especialmente de porco ou carneiro, os açougueiros, magarefes, salsicheiros etc. São particularmente vulneráveis os que tratam com produtos do mar, pescadores, mercadores de siris, camarões, crustáceos, peixes em geral, pela facilidade com que se podem ferir e adquirir a infecção por picada ocasional. A doença atinge numerosos animais domésticos ou não, com formas clínicas bem definidas no porco (erisipela dos porcos, no carneiro (poliartrite dos carneiros, em animais de corte e de tração, em aves domésticas ou de rapina, ratos e camundongos, além de outros numerosos roedores. Moscas hematófagas e outros insetos têm sido encontrados infectados. Nunca é demais frisar que os produtos do mar são grande fonte de infecção humana. No homem, tem a dcença em geral, caráter benigno e localizado (erisipelóide, podendo em certas circunstâncias assumir característica septicêmica como no porco, produzir endocardite, como no carneiro além de outras formas clínicas e complicações. São resumidos no texto os três casos anteriormente apresentados e bem descritos os três inéditos, que têm história clínica e evolução típicas de erisipelóide. Tratando-se de doença com características tipicamente

  1. 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.

  2. Dynamics of the Heat Stress Response of Ceramides with Different Fatty-Acyl Chain Lengths in Baker's Yeast.

    Directory of Open Access Journals (Sweden)

    Po-Wei Chen

    2015-08-01

    Full Text Available The article demonstrates that computational modeling has the capacity to convert metabolic snapshots, taken sequentially over time, into a description of cellular, dynamic strategies. The specific application is a detailed analysis of a set of actions with which Saccharomyces cerevisiae responds to heat stress. Using time dependent metabolic concentration data, we use a combination of mathematical modeling, reverse engineering, and optimization to infer dynamic changes in enzyme activities within the sphingolipid pathway. The details of the sphingolipid responses to heat stress are important, because they guide some of the longer-term alterations in gene expression, with which the cells adapt to the increased temperature. The analysis indicates that all enzyme activities in the system are affected and that the shapes of the time trends in activities depend on the fatty-acyl CoA chain lengths of the different ceramide species in the system.

  3. Study on the High-sugar-tolerant Baker's Yeast%耐高糖面包酵母的研究

    Institute of Scientific and Technical Information of China (English)

    刘湄; 肖冬光; 代丽昕

    2001-01-01

    实验表明,蔗糖酶活力低的菌株,在高糖面团中发酵力较好;而麦芽糖适应性好的菌株,在无糖面团中起发速度较快.从12株原始菌株中选出蔗糖酶活力最低,且麦芽糖适应性较好的BY-6菌进行DES诱变,以葡萄糖氧化酶-辣根过氧化物酶-邻联茴香胺偶联反应平板作为初筛平板,经蔗糖酶活力复筛得到4株酶活力降低了的突变株.其中M-26菌蔗糖酶活力降低幅度最大,比BY-6茵降低了27.04%,且麦芽糖适应性有所提高.经测定,4株突变株的发酵性能良好.

  4. Optimising enzyme production by bakers yeast in continuous culture: physiological knowledge useful for process design and control

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, M.E. [Centre for Process Systems Engineering, Imperial Coll. of Science, Technology and Medicine, London (United Kingdom); Bulmer, M. [Advanced Centre for Biochemical Engineering, University Coll., London (United Kingdom); Bogle, I.D.L. [Advanced Centre for Biochemical Engineering, University Coll., London (United Kingdom); Titchener-Hooker, N. [Advanced Centre for Biochemical Engineering, University Coll., London (United Kingdom)

    1996-10-01

    Saccharomyces cerevisiae was grown in aerobic continuous culture on a defined minimal medium, with glucose (40 g.l{sup -1}) as the growth-limiting carbon source, to acquire knowledge useful in process design and for model-based control. Steady-state concentrations of biomass, glucose, ethanol and activities of model products alcohol dehydrogenase, hexokinase, malate dehydrogenase, glucose-6-phosphate dehydrogenase and iso-citrate dehydrogenase were determined at dilution rates (D) between 0.06 h{sup -1} and 0.323 h{sup -1} (close to {mu}{sub max}). Enzyme activities showed productivity trends related to the transition from oxidative to oxido-reductive growth. Conclusions are drawn from the data with regard to designing a new process for production of intracellular enzymes. Issues of process stability as well as productivity are discussed. (orig.). With 5 figs.

  5. Analysis of the Involvement of Different Ceramide Variants in the Response to Hydroxyurea Stress in Baker's Yeast.

    Directory of Open Access Journals (Sweden)

    Po-Wei Chen

    Full Text Available Sphingolipids have been identified as important signaling compounds in stress responses. However, it is not always clear how different sphingolipid profiles are achieved in a particular stress situation. Here we propose a detailed mass action model, containing 42 dependent variables and 137 reactions, that offers explanations of the roles of variant ceramides species, which differ in the lengths of their fatty acyl chains and their saturation state, in the response to hydroxyurea stress. The simulations demonstrate that the cells manage to achieve hydroxyurea tolerance through a well-coordinated, differential usage of the variant ceramide species. Moreover, the results suggest that key enzymes have different affinities toward saturated and unsaturated fatty acyl chains, which implies that the saturation state affords the cells with an additional mode of regulation that had not been recognized so far. These conclusions from our computational analysis are yet to be validated experimentally.

  6. Gene engineering in yeast for biodegradation: Immunological cross-reactivity among cytochrome p-450 system proteins of saccharomyces cerevisiae and candida tropicalis

    Energy Technology Data Exchange (ETDEWEB)

    Loper, J.C.; Chen, C.; Dey, C.R.

    1993-01-01

    Yeasts are eukaryotic microorganisms whose cytochrome P-450 monooxygenase systems may be amenable to genetic engineering for the hydroxylation and detoxication of polychlorinated aromatic hydrocarbons. The molecular genetic properties of strains of bakers yeast, Saccharomyces cerevisiae, and an n-alkane utilizing yeast, Candida tropicalis ATCC750 are examined. Standard methods were used to purify cytochrome P-450 and NADPH-cytochrome c (P-450) reductase proteins from cells cultured by semi-anaerobic glucose fermentation (S. cerevisiae, C. tropicalis) and by growth on tetradecane (C. tropicalis). Polyvalent antisera prepared in rabbits to some of these proteins were used in tests of immunological relatedness among the purified proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and nitrocellulose filter immunoblots. The results provide evidence for gene relationships which should prove useful in gene isolation and subsequent engineering of P-450 enzyme systems in yeast.

  7. 16 years research on lactic acid production with yeast - ready for the market?

    Science.gov (United States)

    Sauer, Michael; Porro, Danilo; Mattanovich, Diethard; Branduardi, Paola

    2010-01-01

    The use of plastic produced from non-renewable resources constitutes a major environmental problem of the modern society. Polylactide polymers (PLA) have recently gained enormous attention as one possible substitution of petroleum derived polymers. A prerequisite for high quality PLA production is the provision of optically pure lactic acid, which cannot be obtained by chemical synthesis in an economical way. Microbial fermentation is therefore the commercial option to obtain lactic acid as monomer for PLA production. However, one major economic hurdle for commercial lactic acid production as basis for PLA is the costly separation procedure, which is needed to recover and purify the product from the fermentation broth. Yeasts, such as Saccharomyces cerevisiae (bakers yeast) offer themselves as production organisms because they can tolerate low pH and grow on mineral media what eases the purification of the acid. However, naturally yeasts do not produce lactic acid. By metabolic engineering, ethanol was exchanged with lactic acid as end product of fermentation. A vast amount of effort has been invested into the development of yeasts for lactic acid production since the first paper on this topic by Dequin and Barre appeared 1994. Now yeasts are very close to industrial exploitation - here we summarize the developments in this field.

  8. Effect of ultrafiltration of yeast extracts on their ability to promote lactic acid bacteria growth.

    Science.gov (United States)

    Gaudreau, H; Champagne, C P; Conway, J; Degré, R

    1999-11-01

    Five yeast extracts (YE) were fractionated by ultrafiltration (UF) with 1, 3, and 10 kDa molecular weight cutoff membranes, concentrated by freeze-drying, and the resulting powders of yeast extract filtrates (YEF) were evaluated for their growth-promoting properties on nine cultures of lactic acid bacteria (LAB). There was an increase in alpha-amino nitrogen content of the YEF powders as the pore size of the UF membranes used to filter the YE solutions decreased. The source of YE had a much greater effect than UF on the growth of LAB. This was also the case for the YEF contents in total and alpha-amino nitrogen. Growth curves of the LAB showed that maximum growth rate (mumax) data were on average 30% higher with bakers' YE than with brewers' YE, while maximum optical density (ODmax) values were on average 16% higher with bakers' YE. This could be related to the higher nitrogen content of the bakers' YE used in this study. Modification by UF of the YE had no significant influence on the growth of 4 of the 9 LAB strains. The three strains of Lactobacillus casei were negatively influenced by UF, as they did not grow as well in the media containing the YEF obtained after filtering with 1 and 3 kDa membranes. On a total solids basis, the 2.5 x retentates from the 10 kDa membrane gave, on average, 4% lower mumax and 5% lower ODmax values as compared to cultures where the corresponding YEF was used as medium supplement. This could also be partially related to the different nitrogen contents of the filtrates and retentates.

  9. Rediscovery of Tetranychus abacae Baker & Pritchard, additional description and notes on South American spider mites (Acari, Prostigmata, Tetranychidae

    Directory of Open Access Journals (Sweden)

    Carlos H.W Flechtmann

    1996-01-01

    Full Text Available The rediscovery of Tetranychus abacae Baker & Pritchard, 1962 is reported and additional description and drawings presented. New host and distribution records for 19 species of spider mites (Tctranychidae in South America are given.

  10. CRED 5 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Isand Areas, Central Pacific. Almost complete bottom coverage...

  11. CRED 40 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  12. Quantitative analysis of photoquadrats 1-35 acquired at Baker Island permanent transect site 5P on March 19, 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This spreadsheet summarizes the number of corals photographed along a permanent transect line at Underwater Site 5P at Baker Island on 3/19/2000.

  13. CRED REA Fish Team Stationary Point Count Surveys at Baker, Pacific Remote Island Areas (PRIAs) in 2006

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stationary Point Counts at 4 stations at each survey site were surveyed as part of Rapid Ecological Assessments (REA) conducted at 9 sites around Baker in the...

  14. CRED 5 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom coverage...

  15. CRED 40 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (NetCDF Format)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (40 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Island Areas, Central Pacific. Almost complete bottom...

  16. The indentation of pressurized elastic shells: from polymeric capsules to yeast cells

    KAUST Repository

    Vella, D.

    2011-08-10

    Pressurized elastic capsules arise at scales ranging from the 10 m diameter pressure vessels used to store propane at oil refineries to the microscopic polymeric capsules that may be used in drug delivery. Nature also makes extensive use of pressurized elastic capsules: plant cells, bacteria and fungi have stiff walls, which are subject to an internal turgor pressure. Here, we present theoretical, numerical and experimental investigations of the indentation of a linearly elastic shell subject to a constant internal pressure. We show that, unlike unpressurized shells, the relationship between force and displacement demonstrates two linear regimes. We determine analytical expressions for the effective stiffness in each of these regimes in terms of the material properties of the shell and the pressure difference. As a consequence, a single indentation experiment over a range of displacements may be used as a simple assay to determine both the internal pressure and elastic properties of capsules. Our results are relevant for determining the internal pressure in bacterial, fungal or plant cells. As an illustration of this, we apply our results to recent measurements of the stiffness of baker\\'s yeast and infer from these experiments that the internal osmotic pressure of yeast cells may be regulated in response to changes in the osmotic pressure of the external medium.

  17. Topics in noncommutative algebra the theorem of Campbell, Baker, Hausdorff and Dynkin

    CERN Document Server

    Bonfiglioli, Andrea

    2012-01-01

    Motivated by the importance of the Campbell, Baker, Hausdorff, Dynkin Theorem in many different branches of Mathematics and Physics (Lie group-Lie algebra theory, linear PDEs, Quantum and Statistical Mechanics, Numerical Analysis, Theoretical Physics, Control Theory, sub-Riemannian Geometry), this monograph is intended to: 1) fully enable readers (graduates or specialists, mathematicians, physicists or applied scientists, acquainted with Algebra or not) to understand and apply the statements and numerous corollaries of the main result; 2) provide a wide spectrum of proofs from the modern literature, comparing different techniques and furnishing a unifying point of view and notation; 3) provide a thorough historical background of the results, together with unknown facts about the effective early contributions by Schur, Poincaré, Pascal, Campbell, Baker, Hausdorff and Dynkin; 4) give an outlook on the applications, especially in Differential Geometry (Lie group theory) and Analysis (PDEs of subelliptic type); ...

  18. Assessment of increased thermal activity at Mount Baker, Washington, March 1975-March 1976

    Science.gov (United States)

    Frank, David; Meier, Mark Frederick; Swanson, Donald A.; with contributions by Babcock, James W.; Fretwell, Marvin O.; Malone, Stephen D.; Rosenfeld, Charles L.; Shreve, Ronald L.; Wilcox, Ray E.

    1977-01-01

    In March 1975 Mount Baker showed a large increase in thermal emission, which has persisted for more than 1 year. Fumarole ejecta accompanied the thermal activity from March to September, but the ejecta had no constituents that suggest a magmatic source. Estimates of that part of the total heat flux that would account for the observed snow and ice loss show that the heat-flow increase was roughly one order of magnitude, from about 2 megawatts at 10 watts per square meter, averaged over Sherman Crater before 1975, to about 30 megawatts at 180 watts per square meter, during 1975. Almost half of the glacier that occupied the basin of Sherman Crater was melted in 1975. The new activity generated great concern among the public and the government agencies responsible for geological evaluation of potential hazards and for protection of life and property. The past geologic history, current topography, rock alteration, and location of major fumarolic activity indicate that large rock avalanches and mudflows on the east slope in Boulder Creek valley are the potential hazards of most significance related to present conditions. The most probable types of large mass movements would be mudflows, having speeds of as much as 50 kilometers per hour, that would originate from mixtures of snow, ice, and melt water and avalanches of structurally weak clay-rich rocks that make up the rim of Sherman Crater. Similar mudflows from the volcano have traveled at least 12 kilometers 8 times during the past 10,000 years. A possible worst case event, however, might be a larger, air-cushioned avalanche of as much as 20 to 30 million cubic meters that could hit Baker Lake at speeds of more than 300 kilometers per hour and generate a wave of water large enough to overtop Upper Baker Dam. At least 30 million cubic meters of potentially unstable material occurs as hydrothermally altered remnants of the rim of Sherman Crater and could provide the required volume for the estimated worst case event or

  19. 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...

  20. Vaginal Yeast Infections

    Science.gov (United States)

    ... infection caused by a type of fungus called candida albicans . Yeast infections usually happen in warm, moist parts of the body, like the mouth, or vagina. We all have candida in our bodies, but usually it's kept in ...

  1. Furoquinoline Alkaloids and Methoxyflavones from the Stem Bark of Melicope madagascariensis (Baker T.G. Hartley

    Directory of Open Access Journals (Sweden)

    Vincent E. Rasamison

    2016-09-01

    Full Text Available Abstract Melicope madagascariensis (Rutaceae is an endemic plant species of Madagascar that was first classified as a member of the genus Euodia J. R. & G. Forst (Rutaceae under the scientific name Euodia madagascariensis Baker. Based on morphological characteristics, Thomas Gordon Hartley taxonomically revised E. madagascariensis Baker to be M. madagascariensis (Baker T.G. Hartley. Chemotaxonomical studies have long been used to help the identification and confirmation of taxonomical classification of plant species and botanicals. Aiming to find more evidences to support the taxonomical revision performed on E. madagascariensis, we carried out phytochemical investigation of two samples of the plant. Fractionation of the ethanol extracts prepared from two stem bark samples of M. madagascariensis (Baker T.G. Hartley led to the isolation of seven known furoquinoline alkaloids 1–7 and two known methoxyflavones 8 and 9. The presence of furoquinoline alkaloids and methoxyflavones in the title species is in agreement with its taxonomic transfer from Euodia to Melicope. Antiprotozoal evaluation of the isolated compounds showed that 6-methoxy-7-hydroxydictamnine (heliparvifoline, 3 showed weak antimalarial activity (IC50 = 35 µM against the chloroquine-resistant strain Dd2 of Plasmodium falciparum. Skimmianine (4 displayed moderate cytotoxicity with IC50 value of 1.5 µM against HT-29 colon cancer cell line whereas 3,5-dihydroxy-3′,4′,7-trimethoxyflavone (9 was weakly active in the same assay (IC50 = 13.9 µM. Graphical Abstract

  2. Demonstration of an infected popliteal (Baker's) cyst with three-phase skeletal scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Wallner, R.J.; Dadparvar, S.; Croll, M.N.; Brady, L.W.

    1985-03-01

    A case is reported of an infected popliteal (Baker's) cyst demonstrated with triple phase skeletal scintigraphy. Although double-contrast arthrography and ultrasonography are currently the modalities most frequently employed to diagnose the presence of popliteal cysts, they may also be detected utilizing this radionuclide technique in the course of evaluation for knee joint disease or septic arthritis. Radionuclide studies may be more sensitive for the evaluation of associated inflammatory disease involving the knee joint.

  3. Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

    Energy Technology Data Exchange (ETDEWEB)

    Tuenge, Jason R.

    2011-06-01

    The U.S. Department of Energy (DOE) is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service (NPS) views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other NPS tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr for this tunnel to a much larger figure national

  4. Dimension and measure of baker-like skew-products of $\\beta$-transformations

    CERN Document Server

    Färm, David

    2010-01-01

    We consider a generalisation of the baker's transformation, consisting of a skew-product of contractions and a $\\beta$-transformation. The Hausdorff dimension and Lebesgue measure of the attractor is calculated for a set of parameters with positive measure. The proofs use a new transverality lemma similar to Solomyak's [Solomyak, 1995]. This transversality, which is applicable to the considered class of maps holds for a larger set of parameters than Solomyak's transversality.

  5. 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.

  6. 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

  7. The genome of wine yeast Dekkera bruxellensis provides a tool to explore its food-related properties.

    Science.gov (United States)

    Piškur, Jure; Ling, Zhihao; Marcet-Houben, Marina; Ishchuk, Olena P; Aerts, Andrea; LaButti, Kurt; Copeland, Alex; Lindquist, Erika; Barry, Kerrie; Compagno, Concetta; Bisson, Linda; Grigoriev, Igor V; Gabaldón, Toni; Phister, Trevor

    2012-07-01

    The yeast Dekkera/Brettanomyces bruxellensis can cause enormous economic losses in wine industry due to production of phenolic off-flavor compounds. D. bruxellensis is a distant relative of baker's yeast Saccharomyces cerevisiae. Nevertheless, these two yeasts are often found in the same habitats and share several food-related traits, such as production of high ethanol levels and ability to grow without oxygen. In some food products, like lambic beer, D. bruxellensis can importantly contribute to flavor development. We determined the 13.4 Mb genome sequence of the D. bruxellensis strain Y879 (CBS2499) and deduced the genetic background of several "food-relevant" properties and evolutionary history of this yeast. Surprisingly, we find that this yeast is phylogenetically distant to other food-related yeasts and most related to Pichia (Komagataella) pastoris, which is an aerobic poor ethanol producer. We further show that the D. bruxellensis genome does not contain an excess of lineage specific duplicated genes nor a horizontally transferred URA1 gene, two crucial events that promoted the evolution of the food relevant traits in the S. cerevisiae lineage. However, D. bruxellensis has several independently duplicated ADH and ADH-like genes, which are likely responsible for metabolism of alcohols, including ethanol, and also a range of aromatic compounds.

  8. The genome of wine yeast Dekkera bruxellensis provides a tool to explore its food-related properties

    Energy Technology Data Exchange (ETDEWEB)

    Piskur, Jure; Ling, Zhihao; Marcet-Houben, Marina; Ishchuk, Olena P.; Aerts, Andrea; LaButti, Kurt; Copeland, Alex; Lindquist, Erika; Barry, Kerrie; Compagno, Concetta; Bisson, Linda; Grigoriev, Igor V.; Gabaldon, Toni; Phister, Trevor

    2012-03-14

    The yeast Dekkera/Brettanomyces bruxellensis can cause enormous economic losses in wine industry due to production of phenolic off-flavor compounds. D. bruxellensis is a distant relative of baker's yeast Saccharomyces cerevisiae. Nevertheless, these two yeasts are often found in the same habitats and share several food-related traits, such as production of high ethanol levels and ability to grow without oxygen. In some food products, like lambic beer, D. bruxellensis can importantly contribute to flavor development. We determined the 13.4 Mb genome sequence of the D. bruxellensis strain Y879 (CBS2499) and deduced the genetic background of several ?food-relevant? properties and evolutionary history of this yeast. Surprisingly, we find that this yeast is phylogenetically distant to other food-related yeasts and most related to Pichia (Komagataella) pastoris, which is an aerobic poor ethanol producer. We further show that the D. bruxellensis genome does not contain an excess of lineage specific duplicated genes nor a horizontally transferred URA1 gene, two crucial events that promoted the evolution of the food relevant traits in the S. cerevisiae lineage. However, D. bruxellensis has several independently duplicated ADH and ADH-like genes, which are likely responsible for metabolism of alcohols, including ethanol, and also a range of aromatic compounds.

  9. Yeast cytochrome c peroxidase: mutagenesis and expression in Escherichia coli show tryptophan-51 is not the radical site in compound I

    Energy Technology Data Exchange (ETDEWEB)

    Fishel, L.A.; Villafranca, J.E.; Mauro, J.M.; Kraut, J.

    1987-01-27

    Using oligonucleotide-directed site-specific mutagenesis, they have constructed a system for the mutation and expression of yeast cytochrome c peroxidase (CCP, EC 1.11.1.5) in Escherichia coli and applied it to test the hypothesis that Trp-51 is the locus of the free radical observed in compound I of CCP. The system was created by substituting a CCP gene modified by site-directed mutagenesis, CCP(MI), for the fol gene in a vector previously used for mutagenesis and overexpression of dihydrofolate reductase. E. coli transformed with the resulting plasmid produced the CCP(MI) enzyme in large quantities, more than 15 mg/L of cell culture, of which 10% is holo- and 90% is apo-CCP(MI). The apoenzyme was easily converted to holoenzyme by the addition of bovine hemin. Purified CCP(MI) has the same catalytic activity and spectra as bakers' yeast CCP. A mutation has been made in CCP(MI), Trp-51 to Phe. The Phe-51 mutant protein CCP(MI,F51) is fully active, and the electron paramagnetic resonance (EPR) spectrum, at 89 K, of its oxidized intermediate, compound I, displays a strong sharp resonance at g = 2.004, which is very similar to the signal observed for compound I of both bakers' yeast CCP and CCP(MI). However, UV-visible and EPR spectroscopy revealed that the half-life of CCP(MI,F51) compound I at 23 /sup 0/C is only 1.4% of that observed for the compound I forms of CCP(MI) or bakers' yeast CCP. Thus, Trp-51 is not necessary for the formation of the free radical observed in compound I but appears to exert a significant influence on its stability.

  10. 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.

  11. [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.

  12. Transcriptional robustness and protein interactions are associated in yeast

    Directory of Open Access Journals (Sweden)

    Conant Gavin C

    2011-05-01

    Full Text Available Abstract Background Robustness to insults, both external and internal, is a characteristic feature of life. One level of biological organization for which noise and robustness have been extensively studied is gene expression. Cells have a variety of mechanisms for buffering noise in gene expression, but it is not completely clear what rules govern whether or not a given gene uses such tools to maintain appropriate expression. Results Here, we show a general association between the degree to which yeast cells have evolved mechanisms to buffer changes in gene expression and whether they possess protein-protein interactions. We argue that this effect bears an affinity to epistasis, because yeast appears to have evolved regulatory mechanisms such that distant changes in gene copy number for a protein-protein interaction partner gene can alter a gene's expression. This association is not unexpected given recent work linking epistasis and the deleterious effects of changes in gene dosage (i.e., the dosage balance hypothesis. Using gene expression data from artificial aneuploid strains of bakers' yeast, we found that genes coding for proteins that physically interact with other proteins show less expression variation in response to aneuploidy than do other genes. This effect is even more pronounced for genes whose products interact with proteins encoded on aneuploid chromosomes. We further found that genes targeted by transcription factors encoded on aneuploid chromosomes were more likely to change in expression after aneuploidy. Conclusions We suggest that these observations can be best understood as resulting from the higher fitness cost of misexpression in epistatic genes and a commensurate greater regulatory control of them.

  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. Overview of Drilling Completion System for Multilateral Well in Baker Hughes Co.%Baker Hughes多底井分支井钻井完井系统综述

    Institute of Scientific and Technical Information of China (English)

    李洪乾; 李建国

    2000-01-01

    系统介绍Baker Hughes公司对于多底井分支井的分类方法及其相适应的油气藏类型,对Baker Hughes公司研制的ROOT系统的钻井完井工具、功能原理、施工步骤以及完井作业时应该注意的问题详细进行了说明,对Baker Hughes的多底井分支井钻井完井系统的特点进行了总结,并提出几点认识与建议.

  15. A study on the fundamental mechanism and the evolutionary driving forces behind aerobic fermentation in yeast.

    Directory of Open Access Journals (Sweden)

    Arne Hagman

    Full Text Available Baker's yeast Saccharomyces cerevisiae rapidly converts sugars to ethanol and carbon dioxide at both anaerobic and aerobic conditions. The later phenomenon is called Crabtree effect and has been described in two forms, long-term and short-term effect. We have previously studied under fully controlled aerobic conditions forty yeast species for their central carbon metabolism and the presence of long-term Crabtree effect. We have also studied ten steady-state yeast cultures, pulsed them with glucose, and followed the central carbon metabolism and the appearance of ethanol at dynamic conditions. In this paper we analyzed those wet laboratory data to elucidate possible mechanisms that determine the fate of glucose in different yeast species that cover approximately 250 million years of evolutionary history. We determine overflow metabolism to be the fundamental mechanism behind both long- and short-term Crabtree effect, which originated approximately 125-150 million years ago in the Saccharomyces lineage. The "invention" of overflow metabolism was the first step in the evolution of aerobic fermentation in yeast. It provides a general strategy to increase energy production rates, which we show is positively correlated to growth. The "invention" of overflow has also simultaneously enabled rapid glucose consumption in yeast, which is a trait that could have been selected for, to "starve" competitors in nature. We also show that glucose repression of respiration is confined mainly among S. cerevisiae and closely related species that diverged after the whole genome duplication event, less than 100 million years ago. Thus, glucose repression of respiration was apparently "invented" as a second step to further increase overflow and ethanol production, to inhibit growth of other microbes. The driving force behind the initial evolutionary steps was most likely competition with other microbes to faster consume and convert sugar into biomass, in niches that

  16. Jazz as individual expression: an analysis of 'The Fabulous Baker Boys' soundtrack

    OpenAIRE

    Biggs, A.

    2014-01-01

    'The Fabulous Baker Boys' (1989) by Kloves is a fictional account of a frustrated sibling piano duo who, in order to liven up their act, hire a singer. As well as a portrayal of sibling rivalry, the film is a study of the working jazz musician and the suppression and expression of individual identity. The film’s soundtrack, arranged, composed and performed by jazz pianist Dave Grusin, uses jazz standards and original thematic compositions that work as ‘ambi-diegetic cinemusical moments’ (Holb...

  17. Comment on ‘Special-case closed form of the Baker-Campbell-Hausdorff formula’

    Science.gov (United States)

    Lo, C. F.

    2016-05-01

    Recently Van-Brunt and Visser (2015 J. Phys. A: Math. Theor. 48 225207) succeeded in explicitly evaluating the Baker-Campbell-Hausdorff (BCH) expansion series for the noncommuting operators X and Y, provided that the two operators satisfy the commutation relation: [X,Y]={uX}+{vY}+{cI}, and the operator I commutes with both of them. In this comment we show that the closed-form BCH formula of this special case can be straightforwardly derived by the means of the Wei-Norman theorem and no summation of the infinite series is needed.

  18. Reactivation or expansion of Hotel Baker Hydro plant. Feasibility assessment report

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    The Hotel Baker Hydroelectric Power plant, built in 1928 at St. Charles, IL., has two generating units which until 1970 supplied the hotel with 100 kW output at 6 ft. head. The feasibility of reactivating, upgrading, or replacing these units to again supply power for the hotel was evaluated considering installation and operating costs, financing requirements, environmental impacts, and regulatory requirements. It was concluded that the reactivation project is marginally attractive only with full use of the power output by an expanded hotel and if electric utility rates increase at 8% per year. (LCL)

  19. Plant regeneration from excised bulb scale segments of Zephyranthes robusta Baker

    Directory of Open Access Journals (Sweden)

    Mirosława Furmanowa

    2014-01-01

    Full Text Available Zephyranthes robusta Baker excised bulb scale segments with the basal plate were grown on Murashige and Skoog (MS medium in four modifications. The cultures were kept at 25°C in darkness. The best results (bulbing, leaf development and rooting were obtained on MS medium with 1 mg/l IBA, 2-6 bulblets being developed from one explant. After 6 weeks the plantlets (4-6 cm high were transferred to pots filled with sterilized soil mixes. After two months the leaves of the plants reached a length of 20 cm.

  20. A major baker's asthma allergen from rye flour is considerably more active than its barley counterpart.

    Science.gov (United States)

    García-Casado, G; Armentia, A; Sánchez-Monge, R; Sánchez, L M; Lopez-Otín, C; Salcedo, G

    1995-05-01

    A rye flour protein of about 13.5 kDa, as well as its barley homologue, have been isolated. The rye component was recognized in vitro by IgE of allergic patients and provoked positive responses in 15 out of 21 baker's asthma patients (71%) when skin prick tests were performed. Its barley homologue showed no detectable in vitro reactivity and caused positive responses in only one-third of patients. Although no inhibitory activity against different alpha-amylases or trypsin was found for these two proteins, their N-terminal sequencing revealed considerable similarity to several members of the cereal alpha-amylase/trypsin inhibitor family.

  1. Baker-Campbell-Hausdorff relation for special unitary groups SU(N)

    CERN Document Server

    Weigert, S

    1997-01-01

    Multiplication of two elements of the special unitary group SU(N) determines uniquely a third group element. A BAker-Campbell-Hausdorff relation is derived which expresses the group parameters of the product (written as an exponential) in terms of the parameters of the exponential factors. This requires the eigen- values of three (N-by-N) matrices. Consequently, the relation can be stated analytically up to N=4, in principle. Similarity transformations encoding the time evolution of quantum mechanical observables, for example, can be worked out by the same means.

  2. [The cloning and expression of the gene for beta-galactosidase from Candida pseudotropicalis yeasts in Saccharomyces cerevisiae cells].

    Science.gov (United States)

    Tretiak, K A; Zakal'skiĭ, A E; Gudz', S P

    1998-01-01

    The gene of beta-galactosidase of lactose-assimilating yeast Candida pseudotropicalis was cloned in pG2 and pBG2-3 hybrid shuttle vectors and expressed in Saccharomyces cerevisiae laboratory strains under the control of own promoter. The plasmids were able to replicate autonomously with relative stability in transformants of baker's yeasts. The availability of glucose or lactose in the medium influenced the recombinant plasmid stability and the expression of the cloned gene. A number of experiments have shown that the LAC+ phenotype in pG2-transformed Saccharomyces cerevisiae was due to the expression of the Candida pseudotropicalis lactose permease gene that is probably located in SaIG1/XhoI DNA fragment about 4.3 kb long. Southern hybridization experiments showed that LAC(+)-transformants of Saccharomyces cerevisiae contained both autonomously-replicative, and integrative pG2 plasmid.

  3. 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.

  4. L-arabinose fermenting yeast

    Science.gov (United States)

    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.

  5. Development of industrial yeast for second generation bioethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Hou, X.

    2012-01-15

    The cost of lignocellulose-based bioethanol needs to be reduced, in order to commercialize this clean and sustainable fuel substitute for fossil fuels. A microorganism that can completely and efficiently convert all the sugars in lignocellulose into ethanol is one of the prerequisites of a cost-effective production process. In addition, the microorganisms should also have a high tolerance towards the inhibitory compounds present in the lignocellulosic hydrolysate, which are formed during the pretreatment of lignocellulose. Baker's yeast, Saccharomyces cerevisiae, is generally regarded as a robust microorganism and can efficiently ferment glucose. But it lacks the ability to ferment xylose which comprises 20-35% of lignocellulose. Naturally xylose-fermenting yeast such as Pichia stipitis is much more sensitive to inhibitors than S. cerevisiae and it requires accurately controlled microaerophilic conditions during the xylose fermentation, rendering the process technically difficult and expensive. In this study, a novel xylose fermenting yeast Spathaspora passalidarum displayed fast cell growth and efficient xylose fermentation under anaerobic conditions. In contrast, P. stipitis was almost unable to utilize xylose under the same conditions. It is further demonstrated that S. passalidarum converts xylose by means of NADH-preferred xylose reductase (XR) and NAD+-dependent xylitol dehydrogenase (XDH). Thus, the capacity of S. passalidarum to utilize xylose under anaerobic conditions is possibly due to a balance between supply and demand of cofactor through this XR-XDH pathway. Only one other XR with NADH preference has been reported so far. Unfortunately, S. passalidarum also has a low tolerance towards inhibitors generated during pretreatment, which prevents immediate use of this yeast in industrial application. S. passalidarum is able to convert the inhibitor furfural to furfuryl alcohol in a synthetic medium when the addition of furfural is low. The enzymes

  6. A Study on the Paul-Baker System as an Instrument for Multi-object Spectrum Observation

    Institute of Scientific and Technical Information of China (English)

    Xiang-Yan Yuan; Ding-Qiang Su; Xiang-Qun Cui; Gen-Rong Liu

    2005-01-01

    Paul-Baker systems with 4° fiat field and 5° flat field are studied. Their light obstructions under different f/ratios of the primary mirror are analyzed. Due to the strong f/ratio of the system, a focal length extender is designed in order to match the following fiber instrumentation, and two kinds of dispersion prism correctors are designed for correcting the atmospheric dispersion. We compare the designed Paul-Baker system with LAMOST, the national major scientific project now under construction.

  7. The essential oil from Vanillosmopsis arborea Baker (Asteraceae presents antinociceptive, anti-inflammatory, and sedative effects

    Directory of Open Access Journals (Sweden)

    Nara Kelly Albuquerque Santos

    2015-01-01

    Full Text Available Background: The essential oil from Vanillosmopsis arborea (EOVA Baker is rich in (--α-bisabolol. Investigations demonstrated its gastroprotective, larvicidal, and visceral antinociceptive activities. Aims: The present study aimed to elucidate the antinociceptive, anti-inflammatory and sedative properties of the EOVA Baker in mice. Materials and Methods: The antinociceptive and anti-inflammatory activities were assessed using the abdominal constriction, formalin and carrageenan-induced paw edema models, respectively. The sedative property was detected by the open-field and sleeping time tests. Results were analyzed by ANOVA, followed by Student-Newman-Keuls test. Results: EOVA, after intraperitoneal administration, produced an inhibition of the acetic acid-induced writhing in mice. In addition, the same doses were able to inhibit both the early and late phases of the formalin-induced nociception. EOVA produced inhibition in the carrageenan-induced edema model, reduced the spontaneous motor activity and prolonged the sleeping time induced by pentobarbital. Conclusion: The experimental data demonstrated that EOVA showed antinociceptive, anti-inflammatory, and sedative activities.

  8. Magma at depth: A retrospective analysis of the 1975 unrest at Mount Baker, Washington, USA

    Science.gov (United States)

    Crider, Juliet G.; Frank, David; Malone, Stephen D.; Poland, Michael P.; Werner, Cynthia; Caplan-Auerbach, Jacqueline

    2011-01-01

    Mount Baker volcano displayed a short interval of seismically-quiescent thermal unrest in 1975, with high emissions of magmatic gas that slowly waned during the following three decades. The area of snow-free ground in the active crater has not returned to pre-unrest levels, and fumarole gas geochemistry shows a decreasing magmatic signature over that same interval. A relative microgravity survey revealed a substantial gravity increase in the ~30 years since the unrest, while deformation measurements suggest slight deflation of the edifice between 1981-83 and 2006-07. The volcano remains seismically quiet with regard to impulsive volcano-tectonic events, but experiences shallow (10 km) long-period earthquakes. Reviewing the observations from the 1975 unrest in combination with geophysical and geochemical data collected in the decades that followed, we infer that elevated gas and thermal emissions at Mount Baker in 1975 resulted from magmatic activity beneath the volcano: either the emplacement of magma at mid-crustal levels, or opening of a conduit to a deep existing source of magmatic volatiles. Decadal-timescale, multi-parameter observations were essential to this assessment of magmatic activity.

  9. Simplifying the Reinsch algorithm for the Baker-Campbell-Hausdorff series

    CERN Document Server

    Van-Brunt, Alexander

    2015-01-01

    The Baker-Campbell-Hausdorff series computes the quantity \\begin{equation*} Z(X,Y)=\\ln\\left( e^X e^Y \\right) = \\sum_{n=1}^\\infty z_n(X,Y), \\end{equation*} where $X$ and $Y$ are not necessarily commuting, in terms of homogeneous multinomials $z_n(X,Y)$ of degree $n$. (This is essentially equivalent to computing the so-called Goldberg coefficients.) The Baker-Campbell-Hausdorff series is a general purpose tool of wide applicability in mathematical physics, quantum physics, and many other fields. The Reinsch algorithm for the truncated series permits one to calculate up to some fixed order $N$ by using $(N+1)\\times(N+1)$ matrices. We show how to further simplify the Reinsch algorithm, making implementation (in principle) utterly straightforward. This helps provide a deeper understanding of the Goldberg coefficients and their properties. For instance we establish strict bounds (and some equalities) on the number of non-zero Goldberg coefficients. Unfortunately, we shall see that the number of terms in the multino...

  10. Origin, distribution, and rapid removal of hydrothermally formed clay at Mount Baker, Washington

    Science.gov (United States)

    Frank, David

    1983-01-01

    Clay minerals are locally abundant in two hydrothermal areas at Mount Baker-Sherman Crater and the Dorr Fumarole Field. The silt- and clay-size fractions of volcanic debris that is undergoing alteration at and near the ground surface around areas of current fumarolic activity in Sherman Crater are largely dominated by alunite and a silica phase, either opal or cristobalite, but contain some kaolinite and smectite. Correspondingly, the chemistry of solutions at the surface of the crater, as represented by the crater lake, favors the formation of alunite over kaolinite. In contrast, vent-filling debris that was ejected to the surface from fumaroles in 1975 contains more than 20 percent clay-size material in which kaolinite and smectite are dominant. The youngest eruptive deposit (probably 19th century) on the crater rim was also altered prior to ejection and contains as much as 27 percent clay-size material in which kaolinite, smectite, pyrophyllite, and mixed-layer illitesmectite are abundant. The hydrothermal products, kaolinite and alunite, are present in significant amounts in five large Holocene mudflows that originated at the upper cone of Mount Baker. The distribution of kaolinite in crater and valley deposits indicates that, with the passage of time, increasingly greater amounts of this clay mineral have been incorporated into large mass movements from the upper cone. Either erosion has cut into more kaolinitic parts of the core of Sherman Crater, or the amount of kaolinite has increased through time in Sherman Crater.

  11. 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....

  12. Short communication: Conversion of lactose and whey into lactic acid by engineered yeast.

    Science.gov (United States)

    Turner, Timothy L; Kim, Eunbee; Hwang, ChangHoon; Zhang, Guo-Chang; Liu, Jing-Jing; Jin, Yong-Su

    2017-01-01

    Lactose is often considered an unwanted and wasted byproduct, particularly lactose trapped in acid whey from yogurt production. But using specialized microbial fermentation, the surplus wasted acid whey could be converted into value-added chemicals. The baker's yeast Saccharomyces cerevisiae, which is commonly used for industrial fermentation, cannot natively ferment lactose. The present study describes how an engineered S. cerevisiae yeast was constructed to produce lactic acid from purified lactose, whey, or dairy milk. Lactic acid is an excellent proof-of-concept chemical to produce from lactose, because lactic acid has many food, pharmaceutical, and industrial uses, and over 250,000 t are produced for industrial use annually. To ferment the milk sugar lactose, a cellodextrin transporter (CDT-1, which also transports lactose) and a β-glucosidase (GH1-1, which also acts as a β-galactosidase) from Neurospora crassa were expressed in a S. cerevisiae strain. A heterologous lactate dehydrogenase (encoded by ldhA) from the fungus Rhizopus oryzae was integrated into the CDT-1/GH1-1-expressing strain of S. cerevisiae. As a result, the engineered strain was able to produce lactic acid from purified lactose, whey, and store-bought milk. A lactic acid yield of 0.358g/g of lactose was achieved from whey fermentation, providing an initial proof of concept for the production of value-added chemicals from excess industrial whey using engineered yeast.

  13. Yeast biomass production: a new approach in glucose-limited feeding strategy

    Directory of Open Access Journals (Sweden)

    Érika Durão Vieira

    2013-01-01

    Full Text Available The aim of this work was to implement experimentally a simple glucose-limited feeding strategy for yeast biomass production in a bubble column reactor based on a spreadsheet simulator suitable for industrial application. In biomass production process using Saccharomyces cerevisiae strains, one of the constraints is the strong tendency of these species to metabolize sugars anaerobically due to catabolite repression, leading to low values of biomass yield on substrate. The usual strategy to control this metabolic tendency is the use of a fed-batch process in which where the sugar source is fed incrementally and total sugar concentration in broth is maintained below a determined value. The simulator presented in this work was developed to control molasses feeding on the basis of a simple theoretical model in which has taken into account the nutritional growth needs of yeast cell and two input data: the theoretical specific growth rate and initial cell biomass. In experimental assay, a commercial baker's yeast strain and molasses as sugar source were used. Experimental results showed an overall biomass yield on substrate of 0.33, a biomass increase of 6.4 fold and a specific growth rate of 0.165 h-1 in contrast to the predicted value of 0.180 h-1 in the second stage simulation.

  14. On the growth of scientific knowledge: yeast biology as a case study.

    Directory of Open Access Journals (Sweden)

    Xionglei He

    2009-03-01

    Full Text Available The tempo and mode of human knowledge expansion is an enduring yet poorly understood topic. Through a temporal network analysis of three decades of discoveries of protein interactions and genetic interactions in baker's yeast, we show that the growth of scientific knowledge is exponential over time and that important subjects tend to be studied earlier. However, expansions of different domains of knowledge are highly heterogeneous and episodic such that the temporal turnover of knowledge hubs is much greater than expected by chance. Familiar subjects are preferentially studied over new subjects, leading to a reduced pace of innovation. While research is increasingly done in teams, the number of discoveries per researcher is greater in smaller teams. These findings reveal collective human behaviors in scientific research and help design better strategies in future knowledge exploration.

  15. Effect of conjugated linoleic acid on fungal delta6-desaturase activity in a transformed yeast system.

    Science.gov (United States)

    Chuang, L T; Thurmond, J M; Liu, J W; Kirchner, S J; Mukerji, P; Bray, T M; Huang, Y S

    2001-02-01

    Conjugated linoleic acid (CLA; 18:2), a group of positional and geometric isomers of linoleic acid (LA; 18:2n-6), has been shown to modulate immune function through its effect on eicosanoid synthesis. This effect has been attributed to a reduced production of n-6 polyunsaturated fatty acid (PUFA), the precursor of eicosanoids. Since delta6-desaturase is the rate-limiting enzyme of the n-6 PUFA production, it is our hypothesis that CLA, which has similar chemical structure to LA, interacts directly with delta6-desaturase. A unique and simple model, i.e., baker's yeast (Saccharomyces cerevisiae) transformed with fungal delta6-desaturase gene, previously established, was used to investigate the direct effect of CLA on delta6-desaturase. This model allows LA to be converted to y-linolenic acid (GLA; 18:3n-6) but not GLA to its metabolite(s). No metabolites of CLA were found in the lipids of the yeast transformed with delta6-desaturase. The inability to convert CLA to conjugated GLA was not due to the failure of yeast cells to take up the CLA isomers. CLA mixture and individual isomers significantly inhibited the activity of delta6-desaturase of the transformed yeast in vivo. Even though its uptake by the yeast was low, CLA c9,t11 isomer was found to be the most potent inhibitor of the four isomers tested, owing to its high inhibitory effect on delta6-desaturase. Since CLA did not cause significant changes in the level of delta6-desaturase mRNA, the inhibition of GLA production could not be attributed to suppression of delta6-desaturase gene expression at the transcriptional level.

  16. Mechanism of untargeted mutagenesis in UV-irradiated yeast

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, C.W.; Christensen, R.B.

    1982-06-01

    The SOS error-prone repair hypothesis proposes that untargeted and targeted mutations in E. coli both result from the inhibition of polymerase functions that normally maintain fidelity, and that this is a necessary precondition for translesion synthesis. Using mating experiments with excision deficient strains of Bakers' yeast, Saccharomyces cerevisiae, we find that up to 40% of cycl-91 revertants induced by UV are untargeted, showing that a reduction in fidelity is also found in irradiated cells of this organism. We are, however, unable to detect the induction or activation of any diffusible factor capable of inhibiting fidelity, and therefore suggest that untargeted and targeted mutations are the consequence of largely different processes. We propose that these observations are best explained in terms of a limited fidelity model. Untargeted mutations are thought to result from the limited capacity of processes which normally maintain fidelity, which are active during replication on both irradiated and unirradiated templates. Even moderate UV fluences saturate this capacity, leading to competition for the limited resource. Targeted mutations are believed to result from the limited, though far from negligible, capacity of lesions like pyrimidine dimers to form Watson-Crick base pairs.

  17. Mechanism of untargeted mutagenesis in UV-irradiated yeast

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, C.W.; Christensen, R.B.

    1982-01-01

    The SOS error-prone repair hypothesis proposes that untargeted and targeted mutations in E. coli both result from the inhibition of polymerase functions that normally maintain fidelity, and that this is a necessary precondition for translesion synthesis. Using mating experiments with excision deficient strains of Bakers' yeast, Saccharomyces cerevisiae, we find that up to 40% of cycl-91 revertants induced by uv are untargeted, showing that a reduction in fidelity is also found in irradiated cells of this organism. We are, however, unable to detect the induction or activation of any diffusible factor capable of inhibiting fidelity, and therefore suggest that untargeted and targeted mutations are the consequence of largely different processes. We propose that these observations are best explained in terms of a limited fidelity model. Untargeted mutations are thought to result from the limited capacity of processes which normally maintain fidelity, which are active during replication on both irradiated and unirradiated templates. Targeted mutations are believed to result from the limited, though far from negligible, capacity of lesions like pyrimidine dimers to form Watson-Crick base pairs.

  18. Performance of a Yeast-mediated Biological Fuel Cell

    Directory of Open Access Journals (Sweden)

    Filip To

    2008-10-01

    Full Text Available Saccharomyces cerevisiae present in common Baker’s yeast was used in a microbial fuel cell in which glucose was the carbon source. Methylene blue was used as the electronophore in the anode compartment, while potassium ferricyanide and methylene blue were tested as electron acceptors in the cathode compartment. Microbes in a mediator-free environment were used as the control. The experiment was performed in both open and closed circuit configurations under different loads ranging from 100 kΩ to 400Ω. The eukaryotic S. cerevisiae-based fuel cell showed improved performance when methylene blue and ferricyanide were used as electron mediators, rendering a maximum power generation of 146.71±7.7 mW/m3. The fuel cell generated a maximum open circuit voltage of 383.6±1.5 mV and recorded a maximum efficiency of 28±1.8 % under 100 kΩ of external load.

  19. Meltwater palaeohydrology of the Baker River basin (Chile/Argentina) during Late Pleistocene deglaciation of the Northern Patagonia Icefield

    Science.gov (United States)

    Thorndycraft, Varyl; Bendle, Jacob; Benito, Gerardo; Sancho, Carlos; Palmer, Adrian; Rodríguez, Xavier

    2016-04-01

    The Late Pleistocene deglaciation of the Northern Patagonia Icefield (NPI) was characterised by rapid ice sheet thinning and retreat, and the development of large proglacial lake systems characterised by continental scale drainage reversals. In this region, research has focused primarily on the identification of former ice-limits (e.g. moraine ridges) for geochronological analyses, with little attention given to the meltwater palaeohydrology of major river valleys. The Baker River catchment drains the majority of the eastern ice shed of the NPI, with a basin area of 29,000 km2 that includes the large transboundary lakes of General Carrera/Buenos Aires and Cochrane/Puerreydón. The Baker River valley is aligned north to south, crossing the east-west valleys of the main NPI outflow glaciers, and thus represents an important aspect of regional Late Pleistocene palaeogeography. The Baker River valley therefore has the potential to refine regional models of deglaciation through better understanding of relationships between glacier dynamics, ice dammed lakes and meltwater pathways. Here we present geomorphological mapping from the Atlantic-Pacific drainage divide (over 150 km east of the Cordillera) to the lower Baker valley, in order to reconstruct Late Pleistocene palaeohydrology. We provide new mapping of palaeolake shoreline elevations and evidence for glacial lake outburst flood (GLOF) pathways that require a re-evaluation of the currently accepted palaeogeographic models. For example, the palaeohydrological evidence does not support existing models of a unified Buenos Aires/Puerreydón mega-lake at ca. 400m elevation. We propose a relative chronology of palaeohydrological events that help refine the published moraine chronology derived from cosmogenic nuclide exposure dating. Controls on Late Pleistocene meltwater palaeohydrology of the Baker catchment are discussed, including the interplay of glacial processes and regional tectonics, in particular, dynamic

  20. Mineral resource assessment map of the Big Gum Swamp Roadless Area, Columbia and Baker counties, Florida

    Science.gov (United States)

    Cathcart, J.B.; Cameron, C.C.; Patterson, S.H.

    1986-01-01

    The Big Gum Swamp Roadless Area (figs, 1 and 2) comprises 13,600 acres in the north-central part of the Osceola National Forest in Columbia and Baker Counties, about 12 airline miles northeast of Lake City, Fla. The area is bounded by Forest Service road 211 and Florida highway 250 on the south, Forest Service roads 233 and 232 on the west and north, and Forest Service road 235 on the east. The area can be reached by traveling 11.7 mi on Florida Highway 250 northeast from its junction with U.S. Highway 441, north of Lake City to the junction of Highway 250 and Forest Service road 233, thence north 1.3 mi on the Forest Service road to the southern corner of the area.

  1. I Teoremi di Campbell, Baker, Hausdorff e Dynkin. Storia, Prove, Problemi Aperti

    Directory of Open Access Journals (Sweden)

    Andrea Bonfiglioli

    2010-12-01

    Full Text Available The aim of this lecture is to provide an overview of facts and references about past and recent results on the Theorem of Campbell, Baker, Hausdorff and Dynkin (shortcut as the CBHD Theorem, following the recent preprint monograph [13]. In particular, we shall give sketches of the following facts: A historical précis of the early proofs (see also [1]; the statement of the CBHD Theorem as usually given in Algebra and that employed in the Analysis of linear PDE's; a review of proofs of the CBHD Theorem (as given by: Bourbaki; Hausdorff; Dynkin; Varadarajan together with a unifying demonstrational approach; an application to the Third Theorem of Lie (in local form. Some new results will be also commented: The intertwinement of the CBHD Theorem with the Theorem of Poincaré-Birkhoff-Witt and with the free Lie algebras (see [12]; recent results on optimal domains of convergence.

  2. Special-case closed form of the Baker-Campbell-Hausdorff formula

    Science.gov (United States)

    Van-Brunt, Alexander; Visser, Matt

    2015-06-01

    The Baker-Campbell-Hausdorff formula is a general result for the quantity Z(X,Y)=ln ({{e}X}{{e}Y}), where X and Y are not necessarily commuting. For completely general commutation relations between X and Y, (the free Lie algebra), the general result is somewhat unwieldy. However in specific physics applications the commutator [X,Y], while non-zero, might often be relatively simple, which sometimes leads to explicit closed form results. We consider the special case [X,Y]=uX+vY+cI, and show that in this case the general result reduces to Furthermore we explicitly evaluate the symmetric function f(u,v)=f(v,u), demonstrating that and relate this to previously known results. For instance this result includes, but is considerably more general than, results obtained from either the Heisenberg commutator [P,Q]=-i\\hbar I or the creation-destruction commutator [a,{{a}\\dagger }]=I.

  3. Characterization of Baker Fjord region through its heavy metal content on sediments (Central Chilean Patagonia

    Directory of Open Access Journals (Sweden)

    Ramón Ahumada

    2015-07-01

    Full Text Available The spatial distribution of heavy metals content (Ba, Cd, Cu, Pb, Sr and Zn in sediments of the Baker Fjord and surrounding channels in the central region of the Chilean fjords (47°45'S, 48°15'S is analyzed. The aim of the study was characterized the patterns of abundance and distribution of these metals in surface sediments. The area corresponds to a poorly studied zone with low human activity. Distribution patterns would be influenced by rainfall conditions (local erosion, fluvial (continental sediments carried by rivers, glacier (glacier flour and estuarine circulation. Cluster analysis allows differentiation among the sampled sites and group with similar characteristics. Finally, the concentrations found were contrasted with average values of metamorphic rocks and show with some certainty that the values found for calendar for this area and the greatest concentrations are the result of natural enrichment.

  4. Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models.

    Science.gov (United States)

    Pfohl-Leszkowicz, A; Hadjeba-Medjdoub, K; Ballet, N; Schrickx, J; Fink-Gremmels, J

    2015-01-01

    The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease

  5. 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 ...

  6. Moraine-dammed lake failures in Patagonia and assessment of outburst susceptibility in the Baker Basin

    Directory of Open Access Journals (Sweden)

    P. Iribarren Anacona

    2014-07-01

    Full Text Available Glacier retreat since the Little Ice Age has resulted in the development or expansion of hundreds of glacial lakes in Patagonia. Some of these lakes have produced large (≥106 m3 Glacial Lake Outburst Floods (GLOFs damaging inhabited areas. GLOF hazard studies in Patagonia have been mainly based on the analysis of short-term series (≤50 years of flood data and until now no attempt has been made to identify the relative susceptibility of lakes to failure. Power schemes and associated infrastructure are planned for Patagonian basins that have historically been affected by GLOFs, and we now require a thorough understanding of the characteristics of dangerous lakes in order to assist with hazard assessment and planning. In this paper, the conditioning factors of 16 outbursts from moraine dammed lakes in Patagonia were analysed. These data were used to develop a classification scheme designed to assess outburst susceptibility, based on image classification techniques, flow routine algorithms and the Analytical Hierarchy Process. This scheme was applied to the Baker Basin, Chile, where at least 7 moraine-dammed lakes have failed in historic time. We identified 386 moraine-dammed lakes in the Baker Basin of which 28 were classified with high or very high outburst susceptibility. Commonly, lakes with high outburst susceptibility are in contact with glaciers and have moderate (>8° to steep (>15° dam outlet slopes, akin to failed lakes in Patagonia. The proposed classification scheme is suitable for first-order GLOF hazard assessments in this region. However, rapidly changing glaciers in Patagonia make detailed analysis and monitoring of hazardous lakes and glaciated areas upstream from inhabited areas or critical infrastructure necessary, in order to better prepare for hazards emerging from an evolving cryosphere.

  7. Moraine-dammed lake failures in Patagonia and assessment of outburst susceptibility in the Baker Basin

    Science.gov (United States)

    Iribarren Anacona, P.; Norton, K. P.; Mackintosh, A.

    2014-12-01

    Glacier retreat since the Little Ice Age has resulted in the development or expansion of hundreds of glacial lakes in Patagonia. Some of these lakes have produced large (≥ 106 m3) Glacial Lake Outburst Floods (GLOFs) damaging inhabited areas. GLOF hazard studies in Patagonia have been mainly based on the analysis of short-term series (≤ 50 years) of flood data and until now no attempt has been made to identify the relative susceptibility of lakes to failure. Power schemes and associated infrastructure are planned for Patagonian basins that have historically been affected by GLOFs, and we now require a thorough understanding of the characteristics of dangerous lakes in order to assist with hazard assessment and planning. In this paper, the conditioning factors of 16 outbursts from moraine-dammed lakes in Patagonia were analysed. These data were used to develop a classification scheme designed to assess outburst susceptibility, based on image classification techniques, flow routine algorithms and the Analytical Hierarchy Process. This scheme was applied to the Baker Basin, Chile, where at least seven moraine-dammed lakes have failed in historic time. We identified 386 moraine-dammed lakes in the Baker Basin of which 28 were classified with high or very high outburst susceptibility. Commonly, lakes with high outburst susceptibility are in contact with glaciers and have moderate (> 8°) to steep (> 15°) dam outlet slopes, akin to failed lakes in Patagonia. The proposed classification scheme is suitable for first-order GLOF hazard assessments in this region. However, rapidly changing glaciers in Patagonia make detailed analysis and monitoring of hazardous lakes and glaciated areas upstream from inhabited areas or critical infrastructure necessary, in order to better prepare for hazards emerging from an evolving cryosphere.

  8. Yeast "make-accumulate-consume" life strategy evolved as a multi-step process that predates the whole genome duplication.

    Directory of Open Access Journals (Sweden)

    Arne Hagman

    Full Text Available When fruits ripen, microbial communities start a fierce competition for the freely available fruit sugars. Three yeast lineages, including baker's yeast Saccharomyces cerevisiae, have independently developed the metabolic activity to convert simple sugars into ethanol even under fully aerobic conditions. This fermentation capacity, named Crabtree effect, reduces the cell-biomass production but provides in nature a tool to out-compete other microorganisms. Here, we analyzed over forty Saccharomycetaceae yeasts, covering over 200 million years of the evolutionary history, for their carbon metabolism. The experiments were done under strictly controlled and uniform conditions, which has not been done before. We show that the origin of Crabtree effect in Saccharomycetaceae predates the whole genome duplication and became a settled metabolic trait after the split of the S. cerevisiae and Kluyveromyces lineages, and coincided with the origin of modern fruit bearing plants. Our results suggest that ethanol fermentation evolved progressively, involving several successive molecular events that have gradually remodeled the yeast carbon metabolism. While some of the final evolutionary events, like gene duplications of glucose transporters and glycolytic enzymes, have been deduced, the earliest molecular events initiating Crabtree effect are still to be determined.

  9. Storage lipids of yeasts: a survey of nonpolar lipid metabolism in Saccharomyces cerevisiae, Pichia pastoris, and Yarrowia lipolytica.

    Science.gov (United States)

    Koch, Barbara; Schmidt, Claudia; Daum, Günther

    2014-09-01

    Biosynthesis and storage of nonpolar lipids, such as triacylglycerols (TG) and steryl esters (SE), have gained much interest during the last decades because defects in these processes are related to severe human diseases. The baker's yeast Saccharomyces cerevisiae has become a valuable tool to study eukaryotic lipid metabolism because this single-cell microorganism harbors many enzymes and pathways with counterparts in mammalian cells. In this article, we will review aspects of TG and SE metabolism and turnover in the yeast that have been known for a long time and combine them with new perceptions of nonpolar lipid research. We will provide a detailed insight into the mechanisms of nonpolar lipid synthesis, storage, mobilization, and degradation in the yeast S. cerevisiae. The central role of lipid droplets (LD) in these processes will be addressed with emphasis on the prevailing view that this compartment is more than only a depot for TG and SE. Dynamic and interactive aspects of LD with other organelles will be discussed. Results obtained with S. cerevisiae will be complemented by recent investigations of nonpolar lipid research with Yarrowia lipolytica and Pichia pastoris. Altogether, this review article provides a comprehensive view of nonpolar lipid research in yeast.

  10. 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

  11. High power density yeast catalyzed microbial fuel cells

    Science.gov (United States)

    Ganguli, Rahul

    Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density

  12. 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...

  13. 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.

  14. Application of biogenic carbon dioxide produced by yeast with different carbon sources for attraction of mosquitoes towards adult mosquito traps.

    Science.gov (United States)

    Sukumaran, D; Ponmariappan, S; Sharma, Atul K; Jha, Hemendra K; Wasu, Yogesh H; Sharma, Ajay K

    2016-04-01

    Surveillance is a prime requisite for controlling arthropod vectors like mosquitoes that transmit diseases such as malaria, dengue and chikungunya. Carbon dioxide (CO2) is one of the main cues from vertebrate breath that attracts mosquitoes towards the host. Hence, CO2 is used as an attractant during surveillance of mosquitoes either from commercial cylinders or dry ice for mosquito traps. In the present study, the biogenic carbon dioxide production was optimized with different carbon sources such as glucose, simple sugar and jaggery with and without yeast peptone dextrose (YPD) media using commercial baker's yeast. The results showed that yeast produced more biogenic CO2 with simple sugar as compared to other carbon sources. Further substrate concentration was optimized for the continuous production of biogenic CO2 for a minimum of 12 h by using 10 g of baker's yeast with 50 g of simple sugar added to 1.5 l distilled water (without YPD media) in a 2-l plastic bottle. This setup was applied in field condition along with two different mosquito traps namely Mosquito Killing System (MKS) and Biogents Sentinel (BGS) trap. Biogenic CO2 from this setup has increased the trapping efficiency of MKS by 6.48-fold for Culex quinquefasciatus, 2.62-fold for Aedes albopictus and 1.5-fold for Anopheles stephensi. In the case of BGS, the efficiency was found to be increased by 3.54-fold for Ae. albopictus, 4.33-fold for An. stephensi and 1.3-fold for Armigeres subalbatus mosquitoes. On the whole, plastic bottle setup releasing biogenic CO2 from sugar and yeast has increased the efficiency of MKS traps by 6.38-fold and 2.74-fold for BGS traps as compared to traps without biogenic CO2. The present study reveals that, among different carbon sources used, simple sugar as a substance (which is economical and readily available across the world) yielded maximum biogenic CO2 with yeast. This setup can be used as an alternative to CO2 cylinder and dry ice in any adult mosquito traps to

  15. Inventory and Monitoring Plan for Howland Island, Baker Island, Jarvis Island National Wildlife Refuges; Units of the Pacific Remote Islands Marine National Monuments

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan documents and prioritizes inventory and monitoring surveys and research currently conducted, and proposed to be conducted, at the Howland Island, Baker...

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 21 CFR 172.896 - Dried yeasts.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  1. A barley flour inhibitor of insect alpha-amylase is a major allergen associated with baker's asthma disease.

    Science.gov (United States)

    Barber, D; Sánchez-Monge, R; Gómez, L; Carpizo, J; Armentia, A; López-Otín, C; Juan, F; Salcedo, G

    1989-05-08

    A barley salt-soluble protein of 14.5 kDa, which inhibits the alpha-amylase from the insect Tenebrio molitor, has been identified as a major IgE-binding component of sera from baker's asthma patients. The N-terminal amino acid sequence of this protein indicates that it is a member of a previously described family of alpha-amylase/trypsin inhibitors.

  2. The Influence of Baker Bay and Sand Island on Circulations in the Mouth of the Columbia River

    Science.gov (United States)

    2014-06-01

    pile dike system and conducted clockwise circulations for 2–3 hours. Eulerian water temperature and salinity depend on many variables, including the...Baker Bay are evaluated next to determine the effects of the pile dikes on water exchange. The salinity and temperature trends were very similar at A2...into the regions between the pile dikes. Highest salinities and coldest temperatures were observed about 1.5 hours after high tide, when saltwater

  3. Consumption of agro-industrial supplies by the baker subsector of Palmira, Valle, Colombia. Consumo de insumos agroindustriales por el subsector panificador de Palmira, Valle del Cauca.

    Directory of Open Access Journals (Sweden)

    Adarme J Wilson

    2007-06-01

    Full Text Available The indicators of agroindustrial consumption in the bakers subsector Pymes play a primary role for designing sustainable strategies for the small craftsman of bread. The administrative, operative and human talent subsystems were evaluated, in 30 of 178 organizations that conformed the bakers subsystems of Palmira on 2005. The estimated annual consumption of wheat flour on 2004 was 2016 t; 348 t of sugar; 240 t of cheese; 54 t of salt; 492 t of margarine; 99 t of yeast; 151200 panels of eggs. With regarding to raw materials it consumes 384000 m3 of natural gas; 1.2 million kw of electric power and 156000 m3 of water. The sector generates 681 direct employments. Map is presented with the location of 86% of the bakeries registered in the Trade Chamber. There is not a unique bakery that had implemented a program of Good Manufacture Practices BPM in an integral way, that meets the National Institute of Medications and Foods Surveillance INVIMA Standars, that has of a system of Hazard Analysis and Critical Control Point (HACCP or have been is to be certified with Quality Assuring Standars (ISO 9000, and/or Environmental Administration (ISO 14000, with occupational health programs (OHSAS 18000 and permanent improvement programs relative to administrative and commercial aspects.Los indicadores de consumo agroindustrial en las Pymes del subsector panificador resultan apremiantes para el diseño de estrategias de sostenibilidad para los pequeños artesanos del pan. Se evaluaron los subsistemas administrativos, talento humano y operativo en 30 de las 178 organizaciones que conformaron el subsistema panificador de Palmira en el 2005. El consumo estimado anual para el 2004 de harina de trigo fue 2.016 t; 348 t de azúcar; 240 t de queso; 54 t de sal; 492 t de margarina; 99 t de levadura; 151.200 paneles de huevos. En materias primas auxiliares consume 384.000 m3 de gas natural; 1.2 millones de kw de energía eléctrica y 156.000 m3 de agua. El sector genera

  4. Simplifying the Reinsch algorithm for the Baker-Campbell-Hausdorff series

    Science.gov (United States)

    Van-Brunt, Alexander; Visser, Matt

    2016-02-01

    The Goldberg version of the Baker-Campbell-Hausdorff series computes the quantity Z ( X , Y ) = ln (" separators=" e X e Y ) = ∑ w g ( w ) w ( X , Y ) , where X and Y are not necessarily commuting in terms of "words" constructed from the {X, Y} "alphabet." The so-called Goldberg coefficients g(w) are the central topic of this article. This Baker-Campbell-Hausdorff series is a general purpose tool of very wide applicability in mathematical physics, quantum physics, and many other fields. The Reinsch algorithm for the truncated series permits one to calculate the Goldberg coefficients up to some fixed word length |w| by using nilpotent (|w| + 1) × (|w| + 1) matrices. We shall show how to further simplify the Reinsch algorithm, making its implementation (in principle) utterly straightforward using "off the shelf" symbolic manipulation software. Specific computations provide examples which help to provide a deeper understanding of the Goldberg coefficients and their properties. For instance, we shall establish some strict bounds (and some equalities) on the number of non-zero Goldberg coefficients. Unfortunately, we shall see that the number of nonzero Goldberg coefficients often grows very rapidly (in fact exponentially) with the word length |w|. Furthermore, the simplified Reinsch algorithm readily generalizes to many closely related but still quite distinct problems—we shall also present closely related results for the symmetric product S ( X , Y ) = ln (" separators=" e X / 2 e Y e X / 2 ) = ∑ w g S ( w ) w ( X , Y ) . Variations on such themes are straightforward. For instance, one can just as easily consider the "loop" product L ( X , Y ) = ln (" separators=" e X e Y e - X e - Y ) = ∑ w g L ( w ) w ( X , Y ) . This "loop" type of series is of interest, for instance, when considering either differential geometric parallel transport around a closed curve, non-Abelian versions of Stokes' theorem, or even Wigner rotation/Thomas precession in special

  5. The effects of mixture commercial live bakers’ yeast and probiotic bacillus on growth and feeding performance and survival rate of silver carp (Hypophthalmichthys molitrix larvae via bioencapsulated Artemia urmiana nauplii

    Directory of Open Access Journals (Sweden)

    Hossein Adineh

    2011-07-01

    Full Text Available Hypophthalmichthys molitrix (Valenciennes, 1844 larvae is an important species forfreshwater aquaculture. This study evaluated the effects of feeding a blend of probiotic bacilli bacteria(B. polymixa, B. licheniformis, B. circulans and baker´s yeast (Saccharomyces cerevisiae on growth and feeding parameters and survival rate of Silver carp larvae. Artemia urmiana (Gǘnther, 1899 nauplii is an important live food that was used as a vector to carry probiotic bacillus to digestive tract of silver carp larvae. The fish larvae were fed at a level of 10 percent body weight at 4 times a day for 30 days. Fish larvae in experimental treatments were fed A. urmiana nauplii that were enriched by blend of 50 percent of Bacillus spp. with concentrations of 1×105, 2×105, 3×105 and 4×105 CFU mL-1 and 50 percent of baker´s yeast with concentrations of 1×105, 2×105, 3×105 and 4×105 cellsmL-1 (T1, T2, T3, T4, respectively and were compared to fish larvae fed control diets of unbioencapsulated A. urmiananauplii. The experiment indicated that feeding and growth parameters in fish fed experimental treatments were significantly higher than fish fed control diets (P<0.05 but survival rate did not significantly differ. Overall, the best group was fed the highest level of yeast and probiotic.

  6. 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...

  7. 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.

  8. 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.

  9. 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...

  10. 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) a...

  11. 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.

  12. 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.

  13. Quiescent hydrogen sulfide and carbon dioxide degassing from Mount Baker, Washington

    Science.gov (United States)

    McGee, K.A.; Doukas, M.P.; Gerlach, T.M.

    2001-01-01

    Volcanic H2S emission rate data are scant despite their importance in understanding magma degassing. We present results from direct airborne plume measurements of H2S and CO2 on a 21-orbit survey at eleven different altitudes around Mount Baker volcano in September 2000 utilizing instrumentation mounted in a light aircraft. Measured emission rates of H2S and CO2 were 5.5 td-1 and 187 td-1 respectively. Maximum concentrations of H2S and CO2 encountered within the 4-km-wide plume were 75 ppb and 2 ppm respectively. Utilizing the H2S signal as a marker for the plume allows the corresponding CO2 signal to be more easily and accurately distinguished from ambient CO2 background. This technique is sensitive enough for monitoring weakly degassing volcanoes in a pre-eruptive condition when scrubbing by hydrothermal fluid or aquifers might mask the presence of more acid magmatic gases such as SO2.

  14. Telescope Fabra ROA Montsec: a new robotic wide-field Baker-Nunn facility

    CERN Document Server

    Fors, O; Muiños, J L; Montojo, F J; Baena-Gallé, R; Boloix, J; Morcillo, R; Merino, M T; Downey, E C; Mazur, M J

    2012-01-01

    A Baker-Nunn Camera (BNC), originally installed at the Real Instituto y Observatorio de la Armada (ROA) in 1958, was refurbished and robotized. The new facility, called Telescope Fabra ROA Montsec (TFRM), was installed at the Observatori Astron\\`omic del Montsec (OAdM). The process of refurbishment is described in detail. Most of the steps of the refurbishment project were accomplished by purchasing commercial components, which involve little posterior engineering assembling work. The TFRM is a 0.5m aperture f/0.96 optically modified BNC, which offers a unique combination of instrumental specifications: fully robotic and remote operation, wide-field of view (4.4 deg x 4.4 deg), moderate limiting magnitude (V~19.5mag), ability of tracking at arbitrary right ascension and declination rates, as well as opening and closing CCD shutter at will during an exposure. Nearly all kind of image survey programs can benefit from those specifications. Apart from other less time consuming programs, since the beginning of sci...

  15. Classification of commutator algebras leading to the new type of closed Baker-Campbell-Hausdorff formulas

    Science.gov (United States)

    Matone, Marco

    2015-11-01

    We show that there are {\\it 13 types} of commutator algebras leading to the new closed forms of the Baker-Campbell-Hausdorff (BCH) formula $$\\exp(X)\\exp(Y)\\exp(Z)=\\exp({AX+BZ+CY+DI}) \\ , $$ derived in arXiv:1502.06589, JHEP {\\bf 1505} (2015) 113. This includes, as a particular case, $\\exp(X) \\exp(Z)$, with $[X,Z]$ containing other elements in addition to $X$ and $Z$. The algorithm exploits the associativity of the BCH formula and is based on the decomposition $\\exp(X)\\exp(Y)\\exp(Z)=\\exp(X)\\exp({\\alpha Y}) \\exp({(1-\\alpha) Y}) \\exp(Z)$, with $\\alpha$ fixed in such a way that it reduces to $\\exp({\\tilde X})\\exp({\\tilde Y})$, with $\\tilde X$ and $\\tilde Y$ satisfying the Van-Brunt and Visser condition $[\\tilde X,\\tilde Y]=\\tilde u\\tilde X+\\tilde v\\tilde Y+\\tilde cI$. It turns out that $e^\\alpha$ satisfies, in the generic case, an algebraic equation whose exponents depend on the parameters defining the commutator algebra. In nine {\\it types} of commutator algebras, such an equation leads to rational solutions for $\\alpha$. We find all the equations that characterize the solution of the above decomposition problem by combining it with the Jacobi identity.

  16. Classification of Commutator Algebras Leading to the New Type of Closed Baker-Campbell-Hausdorff Formulas

    CERN Document Server

    Matone, Marco

    2015-01-01

    We show that there are thirteen {\\it Types} of commutator algebras leading to the new closed forms of the Baker-Campbell-Hausdorff (BCH) formula $$e^Xe^Z=e^{aX+bZ+c[X,Z]+dI} \\ , $$ derived in arXiv:1502.06589, and holding also in cases when $[X,Z]$ includes elements different from $X$ and $Z$. This follows by a rescaled version of the decomposition $e^Xe^Ye^Z=e^Xe^{\\alpha Y} e^{1-\\alpha Y} e^Z$, with $\\alpha$ fixed in such a way that it reduces to the exponential product $e^{\\tilde X}e^{\\tilde Y}$ satisfying the Van-Brunt and Visser condition $[\\tilde X,\\tilde Y]=\\tilde u\\tilde X+\\tilde v\\tilde Y+\\tilde cI$. It turns out that $x:=e^\\alpha$ satisfies, in the generic case, the algebraic equation $$ x^{u+z}-x^u e^{z-w}-x^z e^v+e^{v-w+z}=0 \\ , $$ where $u,v,w$ and $z$ are the parameters in the commutators $[X,Y]=uX+vY+cI$, $[Y,Z]=wY+ zZ+ d I$. We find all the equations that characterize the solution of the above decomposition problem by combining it with the Jacobi Identity.

  17. Telescope Fabra ROA Montsec: A New Robotic Wide Field Baker-Nunn Facility

    Science.gov (United States)

    Fors, Octavi; Núñez, Jorge; Muiños, José Luis; Montojo, Francisco Javier; Baena-Gallé, Roberto; Boloix, Jaime; Morcillo, Ricardo; Merino, María Teresa; Downey, Elwood C.; Mazur, Michael J.

    2013-05-01

    A Baker-Nunn Camera (BNC), originally installed at the Real Instituto y Observatorio de la Armada (ROA) in 1958, was refurbished and robotized. The new facility, called Telescope Fabra ROA Montsec (TFRM), was installed at the Observatori Astronòmic del Montsec (OAdM). The process of refurbishment is described in detail. Most of the steps of the refurbishment project were accomplished by purchasing commercial components, which involve little posterior engineering assembling work. The TFRM is a 0.5 m aperture f/0.96 optically modified BNC, which offers a unique combination of instrumental specifications: fully robotic and remote operation, wide field of view (4°.4 × 4°.4), moderate limiting magnitude (V ~ 19.5 mag), ability of tracking at arbitrary right ascension (α) and declination (δ) rates, as well as opening and closing CCD shutter at will during an exposure. Nearly all kinds of image survey programs can benefit from those specifications. Apart from other less time-consuming programs, since the beginning of science TFRM operations we have been conducting two specific and distinct surveys: super-Earths transiting around M-type dwarfs stars, and geostationary debris in the context of Space Situational Awareness/Space Surveillance and Tracking (SSA/SST) programs. Preliminary results for both cases will be shown.

  18. Phylogeographic studies of Brazilian “campo-rupestre” species: Wunderlichia mirabilis Riedel ex Baker (Asteraceae

    Directory of Open Access Journals (Sweden)

    Maria Imaculada Zucchi

    2009-03-01

    Full Text Available Wunderlichia mirabilis Riedel ex Baker, a Brazilian wind-dispersed tree species, has a disjunct pattern of geographical distribution. This species occurs in ‘campo rupestre’ locations of the Espinhaço Range, and Goiás Mountains, Brazil. The phylogeography of W. mirabilis was reconstructed on the basis of the genetic variability and phylogeny of the nuclear (ITS and chloroplast (trnL non-coding spacer regions. AMOVA and Mantel analysis revealed for both markers that genetic variability is high within populations and moderate-to-high among populations. Rates of seed flow are higher than those of pollen flow, and there is a non-significant genetic x geographic correlation. The spread of Wunderlichia mirabilis probably occurred from Serra do Cabral through other serras in the Espinhaço Range of Minas Gerais and Espírito Santo, in an easterly direction, and through Goiás Mountains, Serra da Canastra in Minas Gerais and São Paulo in a westerly movement from the Serra do Cabral, Minas Gerais.

  19. Topical Antinociceptive Effect of Vanillosmopsis arborea Baker on Acute Corneal Pain in Mice

    Directory of Open Access Journals (Sweden)

    Laura Hévila Inocêncio Leite

    2014-01-01

    Full Text Available This study aimed to assess the possible topical antinociceptive activity of Vanillosmopsis arborea Baker essential oil (EOVA and to clarify the underlying mechanism, using the acute model of chemical (eye wiping nociception in mice. EOVA (25 to 200 mg/kg; p.o. and topical evidenced significant antinociception against chemogenic pain in the test model of formalin-induced neuroinflammatory pain. Local application of 5 M NaCl solution on the corneal surface of the eye produced a significant nociceptive behavior, characterized by eye wiping. The number of eye wipes was counted during the first 30 s. EOVA (25, 50, 100, and 200 mg/kg; p.o. and topical significantly decreased the number of eye wipes. Naloxone, yohimbine, L-NAME, theophylline, glibenclamide, and ruthenium red had no effect on the antinociceptive effect of EOVA. However, ondansetron, p-chlorophenylalanine methyl ester (PCPA, capsazepine, prazosin, and atropine prevented the antinociception induced by EOVA. These results indicate the topical antinociceptive effect of EOVA and showed that 5-HT, α1, TRPV1, and central muscarinic receptors might be involved in the antinociceptive effect of EOVA in the acute corneal model of pain in mice.

  20. Chemical constituents of the essential oil, antioxidant and antibacterial activities from Elettariopsis curtisii Baker.

    Directory of Open Access Journals (Sweden)

    Vanida Chairgulprasert

    2008-08-01

    Full Text Available Elettariopsis curtisii Baker, the culinary and medicinal herb, was investigated to elucidate its chemical constituents and determine antioxidant and antibacterial activities. The essential oil of E. curtisii was obtained by steam distillation of fresh rhizomes in a maximum yield of 0.63%. GC-MS data indicated the presence of six compounds, of which trans-2-decenal (78.03% was the principal constituent. The essential oils and also the hexane, dichloromethane and methanol extracts from the rhizomes and leaves were assessed for antioxidant and antibacterial activities. In an evaluation of antioxidant activity, the crude dichloromethane extract of the leaves exhibited the highest scavenging effect on the DPPH radicalwith an EC50 of 0.28+0.01 mg/mL. The leaf dichloromethane extract also had the highest total phenol concentration, (73.4+2.80 mg GA/g of extract whereas the crude methanol extract from the rhizomes had the highest reducing power with an EC50 of 2.07+0.06 mg/mL. In terms of antibacterial activity, the essential oil (distilled from either the leaves or the rhizomesdisplayed the highest inhibitory activity, with the same MID value of 1 mg/disc against 5 strains of bacteria, Bacillus subtilis,Escherichia coli, Staphylococcus aureus, Sarcina sp. and Pseudomonas aeruginosa.

  1. Longitudinal ultrasound and clinical follow-up of Baker's cysts injection with steroids in knee osteoarthritis.

    Science.gov (United States)

    Bandinelli, Francesca; Fedi, Roberto; Generini, Sergio; Porta, Francesco; Candelieri, Antonio; Mannoni, Alessandro; Innocenti, Massimo; Matucci Cerinic, Marco

    2012-04-01

    This study was conducted to assess ultrasound (US) and clinical changes of Baker's cyst (BC) of patients with knee osteoarthritis (OA) after steroid injection. Patients with knee OA complicated with symptomatic BC (40) were treated with US-guided direct (posterior) aspiration. The injection of 40 mg triamcynolone acetonide was in 20 patients direct into the BC and in other 20 subjects intra-articular (anterior). BC diameters (longitudinal, transverse, and thickness) were measured and followed up with US at baseline, 2, 4, and 8 weeks after injection. Swelling, pain, and range motion were scored at clinical examination with Rauschning and Lindgren classification (RLC, since 0 normal to 3 maximal signs). All US measures of BC and RLC significantly decreased after treatment, in comparison to baseline (p < 0.001) and during the follow-up, did not change through the time (no significant difference between 2, 4, and 8 weeks). At 4 and 8 weeks, diameters measured at US are lower when BC is directly infiltrated in comparison to intra-articular injection (p < 0.01). US steroid direct injection reduces US measures and clinics of BC in knee OA, in particular, when steroid is directly infiltrated into BC.

  2. In vitro multiple shoot regeneration and plant production in Alysicarpus rugosus DC. var. heyneanus Baker.

    Science.gov (United States)

    Bhosle, S V; Thengane, R J; Thengane, S R

    2005-10-01

    A protocol for in vitro multiple shoot regeneration and plant production through seedling (shoot tip) culture was established for Alysicarpus rugosus DC. var. heyneanus Baker. Maximum number of adventitious shoots (14.4) per shoot tip explant were initiated after two subcultures on MS solid medium supplemented with IAA (2.85 microM) plus BAP (2.22 microM) after 4 weeks. Shoot elongation (3.0-3.5 cm) was achieved on MS medium without any hormones. Stunted shoots elongated on half MS medium without growth hormones. Rooting occurred in MS medium containing IAA (1.14 - 2.85 microM) alone or in combination with IBA (0.89 - 2.46 microM) and or NAA (1.07 - 2.69 microM). Maximum rooting was established in MS medium supplemented with IAA (2.85 microM). The plants were acclimatized successfully with 55% survival in pot containing cocoa peat and sand (1:1). After a month, hardened plants were transferred to pots with manure, garden soil and sand (1:2:1) for further growth and finally planted in field.

  3. 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.

  4. Selective Affinity Separation of Yeast Alcohol Dehydrogenase by Reverse Micelles with Unbound Triazine Dye

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfac tant and n-hexanol as cosolvent in the CTAB (50mmol.L-1)/hexanol (15% by volume)/hexane system. Cibacron Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed mi celles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recovery of most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH>pI with electrostatic attraction between YADH and CTAB. The recovery of YADH activity and purification factor have been improved with addition of a small amount of affinity CB. The recovery of YADH activity obtained was ~99% and the purification factor was about 4.0-fold after one cycle of full forward and backward extraction. The low ionic strength in the initial aqueous phase might be responsible for the YADH transfer into the reversed micellar phase.

  5. Selective Affinity Separation of Yeast Alcohol Dehydrogenase by Reverse Micelles with Unbound Triazine Dye*

    Institute of Scientific and Technical Information of China (English)

    张天喜; 刘会洲; 陈家镛

    2001-01-01

    The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfactant and n-hexanol as cosolvent in the CTAB (50 mmol·L- 1)/hexanol (15% by volume)/hexane system. Cibacron Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed micelles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recoveryof most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH>pI with electrostatic attraction between YADH and CTAB. The recovery of YADH activity and purification factor have been improved with addition of a small amount of affinity CB. The recovery of YADH activity obtained was 99% and the purification factor was about 4.0-fold after one cycle of full forward and backward extraction. The low ionic strength in the initial aqueous phase might be responsible for the YADH transfer into the reversed micellar phase.

  6. Characterization of charge isomers of yeast phosphoglycerate kinase. Evidence for intracellular differences.

    Science.gov (United States)

    Arvidsson, L; Schierbeck, B; Larsson-Raźnikiewicz, M

    1976-01-01

    Three electrophoretic components of phosphoglycerate kinase have been isolated from baker's yeast. The isoionic point of the major component is 7.18 at 10 degrees C. Corresponding values for the minor ones are 6.91 and 7.48, respectively. There is a difference of one charge-unit between the isomers 1 and 2, and between the isomers 2 and 3. The release of component 3 from the yeast cells appears in contrast to the isomers 1 and 2 to be promoted by an organic solvent, thus suggesting this component to be bound to the cell-membrane. The amino-terminal amino acid residue appears to be N-acetylated serine in each of the three cases. The carboxyl-terminal ends seem to be identical also with -(Ala, Leu, Val, Lys)- Ala-Lys as the ultimate sequence. From the circular dichroism spectra the contents of alpha-helix and beta-structure were estimated to 15 and 40-50%, respectively. Factors have been determined for transformation and comparison of the specific activities as determined under the various conditions used at different laboratories.

  7. 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

  8. 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.

  9. New examples of membrane protein expression and purification using the yeast based Pdr1-3 expression strategy.

    Science.gov (United States)

    Gupta, Rakeshkumar P; Kueppers, Petra; Schmitt, Lutz

    2014-12-10

    Overexpression and purification of membrane proteins has been a bottleneck for their functional and structural study for a long time. Both homologous and heterologous expression of membrane proteins with suitable tags for purification presents unique challenges for cloning and expression. Saccharomyces cerevisiae is a potential host system with significant closeness to higher eukaryotes and provides opportunity for attempts to express membrane proteins. In the past, bakers yeast containing mutations within the transcriptional regulator Pdr1 has been used to overexpress various membrane proteins including for example the ABC transporters Pdr5 and Yor1, respectively. In this study we exploited this system and tried to express and purify 3 membrane proteins in yeast along with Pdr5 and Yor1 viz. Rsb1, Mdl1 and Drs2 by virtue of an N-terminal 14-histidine affinity tag. Out of these five, we could express all membrane proteins although at different levels. Satisfactory yields were obtained for three examples i.e. Pdr5, Yor1 and Drs2. Rsb1 expression was comparatively low and Mdl1 was rather unsatisfactory. Thus, we demonstrate here the application of this yeast based expression system that is suitable for cloning, expression and purification of a wide variety of membrane proteins.

  10. An improving absorption spectrometry method of yeast biomass concentration estimation using thickening agent%增稠剂改进浊度法测定面包酵母生物量的研究

    Institute of Scientific and Technical Information of China (English)

    王震; 郭祥峰; 贾丽华; 李逸娜

    2013-01-01

    Baker's yeast was treated as modeling microorganism which owned a large particle volume.The subsidence phenomenon baker's yeast during turbidity measurement process was studied.The stability of the baker's yeast was improved by adding hydrolyzable anionic polyacrylamide (HPAM) into the suspension.A standard curve between turbidity and yeast concentration was established of in the thickening system.The results showed that the settlement of the yeast cells was effectively prevented by HPAM,the turbidity exhibited good linearity over the range from 0 to 4.9×106cell/mL with a correlation coefficient of 0.9976,and the detection limit was 1.0×104cell/mL.The average recovery was 100.99%,indicating that this method possessed good accuracy for yeast and was suitable for application in microbial biomass quantitative detection in liquid environment.%以面包酵母为模式微生物,研究了大粒径微生物在浊度测量过程中的沉降现象.通过添加增稠剂水解型阴离子聚丙烯酰胺(HPAM),改善了面包酵母悬浮体系的稳定性,并在增稠体系中建立了浊度与酵母浓度的标准曲线.结果表明,增稠体系中HPAM浓度达到0.100g/L时,可以有效阻止酵母细胞的沉降,悬浮液的浊度与细胞浓度在0~4.9×106个/mL范围内呈现良好的线性关系,相关系数R2=0.9976,检出限为1.0×104个/mL.该方法的平均回收率为100.99%,具有良好的准确性,适用于液体环境中微生物生物量的定量检测.

  11. 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.

  12. Alternative control of Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) on tomato plants grown in greenhouses.

    Science.gov (United States)

    Soto, Alberto; Venzon, Madelaine; Oliveira, Rafael M; Oliveira, Hamilton G; Pallini, Angelo

    2010-01-01

    Tetranychus evansi Baker & Pritchard is an important pest of solanaceous plants, including tomatoes. This mite is characterized by a high reproductive rate, which leads to high population growth in a short period of time causing important economic damage. Control of T. evansi is mainly through synthetic acaricides. In searching for environmentally friendly control measures, we evaluated the efficiency of alternative products to control T. evansi on tomato plants under greenhouse conditions. The products tested were lime sulphur and neem based products. We first estimated the lethal concentration (LC) and instantaneous rate of increase (r i) of T. evansi exposed to different product concentrations in laboratory conditions, and later tested the efficacy of LC95 and the concentrations that restrained mite population growth (r i = 0) in greenhouse conditions. The following treatments were repeated three times: NeemPro (81.0 and 71.6 mg a.i./l), Natuneem (31.1 and 20.4 mg ai/l), Organic Neem (39.1 and 30.4 mg a.i./l), lime sulphur (1.0 and 0.6%) and water (control). For all products, control provided by LC95 was higher than provided for lower concentrations (r i = 0) one day after spraying. However, after five days, for both concentrations, the percentage of T. evansi population reduction was superior to 95% and increased over time. Only plants sprayed with Natuneem (31.1 mg a.i./l) showed symptoms of phytotoxicity. Lime sulphur and neem based products, applied in appropriate concentrations and formulations, bear out as a viable alternative to control T. evansi on tomato plants.

  13. Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

    Energy Technology Data Exchange (ETDEWEB)

    Tuenge, Jason R.

    2011-06-28

    The U.S. Department of Energy is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr to a much larger figure nationally. Most of the energy savings in this application is attributable to the instant-restrike capability of LED products and to their high tolerance for frequent on/off switching, used here to separately control either end of the tunnel during daytime hours. Some LED luminaires rival or outperform their high-intensity discharge (HID) counterparts in terms of efficacy, but options are limited, and smaller lumen packages preclude true one-for-one equivalence. However, LED products continue to improve in efficacy and affordability at a rate unmatched by other light source technologies; the estimated simple payback period of eight years (excluding installation costs and maintenance savings) can be expected to improve with time. The proposed revisions to the existing high-pressure sodium (HPS) lighting system would require slightly increased controls complexity and significantly increased luminaire types and quantities. In exchange, substantial annual savings (from reduced maintenance and energy use) would be complemented by improved quantity and quality of illumination. Although advanced lighting controls could offer additional savings, it is unclear whether such a system would prove cost-effective; this topic may be explored in future work.

  14. Climate change impacts on the Lehman-Baker Creek drainage in the Great Basin National Park

    Science.gov (United States)

    Volk, J. M.

    2013-12-01

    Global climate models (GCMs) forced by increased CO2 emissions forecast anomalously dry and warm trends over the southwestern U.S. for the 21st century. The effect of warmer conditions may result in decreased surface water resources within the Great Basin physiographic region critical for ecology, irrigation and municipal water supply. Here we use downscaled GCM output from the A2 and B1 greenhouse gas emission scenarios to force a Precipitation-Runoff Modeling System (PRMS) watershed model developed for the Lehman and Baker Creeks Drainage (LBCD) in the Great Basin National Park, NV for a century long time period. The goal is to quantify the effects of rising temperature to the water budget in the LBCD at monthly and annual timescales. Dynamically downscaled GCM projections are attained from the NSF EPSCoR Nevada Infrastructure for Climate Change Science, Education, and Outreach project and statistically downscaled output is retrieved from the "U.S. Bias Corrected and Downscaled WCRP CMIP3 Climate Projections". Historical daily climate and streamflow data have been collected simultaneously for periods extending 20 years or longer. Mann-Kendal trend test results showed a statistically significant (α= 0.05) long-term rising trend from 1895 to 2012 in annual and monthly average temperatures for the study area. A grid-based, PRMS watershed model of the LBCD has been created within ArcGIS 10, and physical parameters have been estimated at a spatial resolution of 100m. Simulation results will be available soon. Snow cover is expected to decrease and peak runoff to occur earlier in the spring, resulting in increased runoff, decreased infiltration/recharge, decreased baseflows, and decreased evapo-transpiration.

  15. [Presence of nitrates and nitrites in baker's products and in certain other flour products].

    Science.gov (United States)

    Nabrzyski, M; Gajewska, R; Ganowiak, Z

    1990-01-01

    The results of the study demonstrated that the content of nitrates and nitrites in various baker's products varied from 0.96 (in wheat rolls and baguettes) to 44.07 mg KO3/kg in pumpernickel bread. In wholemeal bread, village bread, tourist bread, rye brown bread and Graham bread the content of these compounds was from 1.46 to 27.10 mg KNO3/kg. The mean content of nitrites in these bread sorts was 1.76 mg NaNo2/kg, range 0.10-4.40 mg NaNo2/kg. In white wheat flours (Wrocław flour, cake flour and Poznań flour) the content of nitrates ranged from 1.10 to 19.08 mg KNO3/kg, and in the dishes produced from them in household was from 0.50 to 16.33 mg KNO3/kg. The content of nitrites in these flours was in the range from 0.00 to 4.16 mg NaNo2/kg, and in the products prepared from them it was from 0.00 to 1.60 mg NaNO2/kg. Eleven types were tested also of popular biscuits, wafers, gingerbread and hard cakes in which the content of nitrates was from 3.66 to 17.72 mg/kg, and that of nitrites was from 0.00 to 8.80 mg NaNo2/kg. Considering the average consumption of these products per one person in the seashore region and the mean values of nitrates and nitrites it was calculated that they provided daily about 3.9 mg KNO3 and 0.4 NaNo2, that is about 1.8% of nitrates and 7.7% of nitrites consumed by adults in daily food ration.

  16. Diet, occupational exposure and early asthma incidence among bakers, pastry makers and hairdressers

    Directory of Open Access Journals (Sweden)

    Rémen Thomas

    2012-05-01

    Full Text Available Abstract Background The natural history of occupational asthma (OA is influenced by many determinants. This study aims to assess the combined roles of personal characteristics, including occupational exposure and nutritional habits, on the incidence of OA during the first years at work. Methods A nested case–control study was conducted within a retrospective cohort of young workers in the bakery, pastry-making and hairdressing sectors. Cases were subjects diagnosed as ‘confirmed’ or ‘probable’ OA consecutively to a medical visit (N = 31. Controls were subjects without OA (N = 196. Atopy was defined after blood specific IgE analysis, based on the PhadiatopTM test. Occupational exposure was characterized by standardized questionnaires and diet patterns by a food frequency questionnaire. Results Among bakers and pastry-makers, only atopy is an independent risk factor of OA (OR = 10.07 95%CI [2.76 – 36.65]. Among hairdressers, several variables are associated with OA. Body mass index (unit OR = 1.24 [1.03 – 1.48] and the score of exposure intensity (unit OR = 1.79 [1.05 – 3.05] are independent predictors of OA, but the role of atopy is weak (OR = 4.94 [0.66 – 36.75]. Intake of vitamin A is higher among hairdressers cases (crude p = 0.002, adjusted p = 0.01 after control for body mass index and atopy; the same observation is made for vitamin D (crude p = 0.004, adjusted p = 0.01. Conclusion This study suggests that the influence of several factors on the incidence of OA, including dietary vitamins, might vary across exposure settings.

  17. Partial methylation at Am100 in 18S rRNA of baker's yeast reveals ribosome heterogeneity on the level of eukaryotic rRNA modification.

    Science.gov (United States)

    Buchhaupt, Markus; Sharma, Sunny; Kellner, Stefanie; Oswald, Stefanie; Paetzold, Melanie; Peifer, Christian; Watzinger, Peter; Schrader, Jens; Helm, Mark; Entian, Karl-Dieter

    2014-01-01

    Ribosome heterogeneity is of increasing biological significance and several examples have been described for multicellular and single cells organisms. In here we show for the first time a variation in ribose methylation within the 18S rRNA of Saccharomyces cerevisiae. Using RNA-cleaving DNAzymes, we could specifically demonstrate that a significant amount of S. cerevisiae ribosomes are not methylated at 2'-O-ribose of A100 residue in the 18S rRNA. Furthermore, using LC-UV-MS/MS of a respective 18S rRNA fragment, we could not only corroborate the partial methylation at A100, but could also quantify the methylated versus non-methylated A100 residue. Here, we exhibit that only 68% of A100 in the 18S rRNA of S.cerevisiae are methylated at 2'-O ribose sugar. Polysomes also contain a similar heterogeneity for methylated Am100, which shows that 40S ribosome subunits with and without Am100 participate in translation. Introduction of a multicopy plasmid containing the corresponding methylation guide snoRNA gene SNR51 led to an increased A100 methylation, suggesting the cellular snR51 level to limit the extent of this modification. Partial rRNA modification demonstrates a new level of ribosome heterogeneity in eukaryotic cells that might have substantial impact on regulation and fine-tuning of the translation process.

  18. Overexpression of O‐methyltransferase leads to improved vanillin production in baker's yeast only when complemented with model‐guided network engineering

    DEFF Research Database (Denmark)

    Brochado, Ana Rita; Patil, Kiran R.

    2013-01-01

    Overproduction of a desired metabolite is often achieved via manipulation of the pathway directly leading to the product or through engineering of distant nodes within the metabolic network. Empirical examples illustrating the combined effect of these local and global strategies have been so far...

  19. 面包酵母海藻糖积累条件的研究%TREHALOSE ACCUMULATION CONDITION IN BAKER'S YEAST

    Institute of Scientific and Technical Information of China (English)

    王兰; 肖冬光

    2002-01-01

    对面包酵母的海藻糖积累条件及补料分批发酵进行了研究.结果表明pH为 5.0,温度 37 ℃有利于海藻糖积累.少量多次的补加葡萄糖可持续增加海藻糖的含量,但随着发酵时间的延长,葡萄糖对海藻糖转化率有逐渐减少的趋势.

  20. Application of Baker's Yeast in Asymmetric Synthesis%面包酵母在催化不对称合成中的应用

    Institute of Scientific and Technical Information of China (English)

    杨忠华; 邹少兰; 梅乐和; 关怡新; 林东强; 姚善泾

    2004-01-01

    介绍了当前国内外在以面包酵母为催化剂不对称催化合成手性化合物的研究情况,重点介绍了面包酵母催化各类潜手性羰基的不对称还原、潜手性碳-碳双键的不对称加成和碳-碳键形成的反应情况,讨论了各种提高酵母催化不对称合成反应立体选择性的方法,对酵母催化不对称合成有关生物学方面的研究进行了简单的介绍.

  1. Stero and Chemoselective Reduction of Ketones and Aldehydes Using Baker's Yeast%面包酵母的立体选择性还原作用

    Institute of Scientific and Technical Information of China (English)

    黄南平; 钟平

    2002-01-01

    面包酵母是一种廉价易得的实验材料,可将酮类化合物还原为具有高光学活性的醇,也可还原醛、烯烃化合物、叠氮化合物等.反应条件温和,操作简单,因此,面包酵母是一种很有发展前途的生化试剂.

  2. Asymmetric Reduction of Acetophenone with Baker's Yeast%面包酵母用于苯乙酮的不对称还原研究

    Institute of Scientific and Technical Information of China (English)

    刘湘; 孙培冬; 李明; 许建和

    2002-01-01

    研究了面包酵母用于苯乙酮的不对称还原,分别考察了反应温度、反应时间、底物浓度等因素对转化率和对映选择性的影响.结果表明,在合适的生物转化条件下,底物苯乙酮以中等的转化率被还原并得到较高对映体过量值的产物S-1-苯基乙醇.

  3. Influence of Selenium on Bakers' Yeast Growth%硒对啤酒酵母细胞生长的影响

    Institute of Scientific and Technical Information of China (English)

    孙海云; 于同立; 王金玉

    2007-01-01

    目的 研究不同硒浓度对啤酒酵母细胞生长的影响,确定适宜的硒添加量.方法 用分光光度计测定不同硒浓度时酵母细胞培养液在不同时间的吸收度,绘制生长曲线,比较硒浓度不同时酵母细胞的生长情况.结果 亚硒酸钠的添加浓度小于20 μg/mL时,有促进酵母菌生长的作用;亚硒酸钠浓度高于30 μg/mL时,对酵母菌生长有明显的抑制作用;亚硒酸钠浓度在20 μg/mL时酵母菌可以正常生长.结论 亚硒酸钠的添加浓度应在20 μg/mL左右.

  4. 面包酵母发酵力测定方法的研究%Study on determination method of baker's yeast fermentation activity

    Institute of Scientific and Technical Information of China (English)

    肖冬光; 刘青; 李静

    2004-01-01

    探讨了面包酵母发酵力的测定方法.结果表明,标准排水法测得的产气量已不能正确反映现代商用面包酵母的发酵力,面团发酵0~2h的产气量与面包酵母发酵力呈正比,可作为衡量面包酵母发酵力的指标.活性干酵母用量在一定范围内,与发酵0.5~1.5h所失去CO2的重量呈正相关,相关系数R2=0.9976,所以发酵0.5~1.5h的CO2的失重量也可作为衡量面包酵母发酵力的指标.失重法无需专用设备,具有重复性好、操作简便易行、可以同时测定大量样品的优点,可作为实验室检测面包酵母发酵力的简易方法.

  5. 面包酵母发酵力测定方法的探讨%Research on determination method of dough fermentation ability in baker's yeast

    Institute of Scientific and Technical Information of China (English)

    姜天笑; 肖冬光; 王振

    2008-01-01

    研究面包酵母面团发酵力的测定方法,讨论在不加糖面团和高糖面团中培养时间与酵母加量的关系,确定了最佳的测定条件,同时对市售8株商品面包酵母进行比较.

  6. 面包酵母耐冷冻性能的评价方法%Investigation on the Determination Methods of Freeze-tolerant Ability in Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    姜天笑; 肖冬光; 董博宇

    2007-01-01

    讨论了面包酵母耐冷冻能力的评价方法,通过对酵母在普通面团中冷冻后的相对发酵力、在液体模拟面团中冷冻后的相对发酵力和酵母细胞冷冻存活率之间的比较,发现3者之间具有显著的线性正相关性.而应用液体模拟面团测定酵母耐冷冻能力的方法简便、易控制,可用于耐冷冻酵母菌种的选育和耐冷冻酵母产品的检测中.

  7. 膜法酵母提取海藻糖应用初探%Development of extracting trehalose from baker's yeast by membrane process

    Institute of Scientific and Technical Information of China (English)

    韩少卿; 慈龙剑; 陈贵锐; 彭奇均

    2004-01-01

    采用超滤-纳滤技术对活性干酵母溶液中的海藻糖进行提取研究,结果表明:MWCO为5000的卷式超滤膜可截留约98%以上的蛋白质,起到纳滤预处理的作用;MWCO为300的卷式纳滤膜对超滤液进行纳滤预浓缩和渗滤操作,发现浓缩过程通量随压力的增加而增加,随浓缩时间的延长而迅速下降,海藻糖截留率变化不大;渗滤过程表明渗透通量随渗滤时间的延长而略有增加,海藻糖截留率变化不大.经过超滤-纳滤处理,海藻糖提取率达85%以上,纯度99.4%,优于传统乙醇提取方法.

  8. 面包酵母耐冷冻性影响因子的研究进展%Study on Influence on Freeze-tolerance of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    和东芹; 肖冬光; 邹静

    2007-01-01

    论述了影响面包酵母耐冷冻性的各种因子.耐冷冻面包酵母是冷冻面团技术的关键,许多因素与酵母冷冻耐受性有关,如酵母胞内海藻糖含量、甘油含量、酒精含量、热休克蛋白含量、不同脂肪成分的比例、某些带电荷的氨基酸含量、呼吸能力、控制质膜的水运送的基因的表达等等,而海藻糖在酵母胞内起到的耐冷冻作用被广泛证明.

  9. 高渗培养对酵母抗冻能力的影响%Effect of Hyperosmotic Cultivation on the Freezing Resistance of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    韩春然; 马永强; 张红薇

    2010-01-01

    研究高渗培养对冷冻面团中的酵母抗冻能力的影响.分别研究16%、18%、20%和22%的葡萄糖对酵母冷冻期间的存活率,面团的产气能力和面团解冻之后重量损失的影响.结果表明:在冷冻5周之内,葡萄糖浓度低于20%.高渗培养可以提高酵母的抗冻能力,表现为酵母的存活率显著提高,面团的产气能力明显增强,冷冻面团解冻之后的重量损失降低.

  10. 海藻糖对面包酵母高糖耐性的影响%Effect of Intercellular Trehalose on the High Sugar Tolerance of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    徐曼; 肖冬光; 郭学武; 姜天笑; 刘宝开

    2008-01-01

    通过高温刺激使面包酵母积累较高的胞内海藻糖,考察胞内海藻糖含量对面包酵母高糖发酵力和高渗存活率的影响.研究结果表明,发酵结束前2 h培养温度提高至40℃后,菌株BY-6胞内海藻糖含量由4.21%提高到9.76%,高糖发酵力提高了17.2%,高渗存活率也有一定提高.另外对3株面包酵母的海藻糖积累能力和面团发酵力的比较表明,海藻糖积累能力强的酵母菌株高糖耐性较好.

  11. 面包酵母酸性海藻糖酶活性测定%Detecting Acidic Trehalase Activity of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    肖冬光; 邹静; 和东芹

    2006-01-01

    首先通过单因素实验研究了pH值、温度、底物浓度对面包酵母酸性海藻糖酶活性的影响,然后通过正交试验得出了酸性海藻糖酶活性测定的适宜条件:海藻糖浓度1.6%、温度30℃、pH 4.0、酵母菌泥接种量为0.02g/mL.在此条件下,海藻糖的消耗量与时间成线性关系,并得出该菌的酸性海藻糖酶活性为338.6 mg/(g·h).可用于面包酵母酸性海藻糖酶活性的测定和耐冷冻酵母菌株的选育.

  12. Determination neutral trehalase activity of baker's yeast%面包酵母中性海藻糖酶活性的测定方法

    Institute of Scientific and Technical Information of China (English)

    邹静; 肖冬光; 宋飞; 谷向春; 和东芹

    2007-01-01

    酵母中性海藻糖酶是受蛋白激酶磷酸化作用调控的酶,其在体内的酶活性与用破壁后提出的酶活性有很大的差异.本文构建了一种活体测定面包酵母中性海藻糖酶活性的方法,在pH为6.8的100mL模拟面团溶液中,接新鲜酵母泥2g,30℃下作用5min,以每克菌体单位时间内胞内海藻糖的消耗量来定义酶的活性.

  13. SCREENING OF BAKER'S YEAST FOR QUICK FERMENTATION IN PLAIN DOUGHS%快速发酵面包酵母菌株的选育

    Institute of Scientific and Technical Information of China (English)

    姜天笑; 肖冬光; 刘青; 胡娅兰

    2006-01-01

    对出发菌株进行紫外-氯化锂复合诱变,通过初筛、复筛选育出高麦芽糖发酵力、低葡萄糖阻遏的面包酵母菌株BM-72,该菌株在不加糖、低糖面团中均表现出较好的发酵力,分别高于出发菌株19.4%和7.3%.

  14. Screening of baker's yeast strains with high melibiose using%利用蜜二糖面包酵母的菌种选育

    Institute of Scientific and Technical Information of China (English)

    姜翔; 肖冬光; 郭学武; 葛彦

    2009-01-01

    对能利用蜜二糖的葡萄汁酵母M-3进行生孢培养和孢子分离,得到122株单倍体,经筛选后得到一株性能优良的单倍体M-3-16(α),作为杂交实验的亲本.将M-3-16(α)与不利用蜜二糖的面包酵母BY-6(a)单倍体进行杂交,共获得杂交株153株.经杜氏管实验、面团发酵力实验和蜜二糖利用实验等,筛选得到一株能利用蜜二糖的面包酵母BM-31.

  15. Optimization of Trehalose Accumulation Conditions in Baker's Yeast%酵母内海藻糖积累条件的优化

    Institute of Scientific and Technical Information of China (English)

    王兰; 肖冬光; 张正; 李绩

    2002-01-01

    对面包酵母(BY-11)海藻糖积累条件进行了较系统的研究,采用了PB和响应曲面设计法,得到了1个优化的培养基.采用此培养基,以3g/L(以酵母干固物计)的接种量,37℃震荡培养3h可积累海藻糖0.96g/L,从而大大提高了海藻糖的产量,为工业生产提供了可行性.

  16. DEFINING THE EFFECTIVENESS OF FACTORS IN PROCESS OF DRYING INDUSTRIAL BAKERS YEAST BY USING TAGUCHI METHOD AND REGRESSION ANALYSIS, AND COMPARING THE RESULTS

    Directory of Open Access Journals (Sweden)

    Semra Boran

    2007-09-01

    Full Text Available Taguchi Method and Regression Analysis have wide spread applications in statistical researches. It can be said that Taguchi Method is one of the most frequently used method especially in optimization problems. But applications of this method are not common in food industry . In this study, optimal operating parameters were determined for industrial size fluidized bed dryer by using Taguchi method. Then the effects of operating parameters on activity value (the quality chracteristic of this problem were calculated by regression analysis. Finally, results of two methods were compared.To summarise, average activity value was found to be 660 for the 400 kg loading and average drying time 26 minutes by using the factors and levels taken from application of Taguchi Method. Whereas, in normal conditions (with 600 kg loading average activity value was found to be 630 and drying time 28 minutes. Taguchi Method application caused 15 % rise in activity value.

  17. Effect of glutathione on freezing resistance of baker's yeast%谷胱甘肽对酵母抗冻能力的影响

    Institute of Scientific and Technical Information of China (English)

    韩春然; 马永强; 苏蕾蕾

    2010-01-01

    研究了不同浓度的谷胱甘肽(CSH)对面团冷冻期间酵母存活率、产气能力及面团重量损失的影响.结果表明:随着冷冻时间的延长,冷冻面团中酵母的存活率越来越低,添加GSH的冷冻面团中的酵母菌落数明显高于未添加的冷冻面团,同时,添加了GSH的面团冷冻之后的产气能力显著高于未添加组,冷冻面团的重量损失则低于未添加组.GSH的添加浓度为0.3mg/kg时保护效果最明显.

  18. 面包酵母发酵力测定方法的探讨%Investigation on Determination Methods of Baker's Yeast Fermentation Ability

    Institute of Scientific and Technical Information of China (English)

    李长文; 肖冬光; 李志勇

    2002-01-01

    探讨了面包酵母发酵力的测定方法.试验结果表明,采用发酵0.5h内面团的产气量(mL)作为面包酵母发酵力的指标,能较好地反映面包酵母产品的质量;面团浮水法设备简单、重复性好,且与排水法之间有良好的相关关系,亦可作为面包酵母发酵力检测的方法.

  19. Partial methylation at Am100 in 18S rRNA of baker's yeast reveals ribosome heterogeneity on the level of eukaryotic rRNA modification.

    Directory of Open Access Journals (Sweden)

    Markus Buchhaupt

    Full Text Available Ribosome heterogeneity is of increasing biological significance and several examples have been described for multicellular and single cells organisms. In here we show for the first time a variation in ribose methylation within the 18S rRNA of Saccharomyces cerevisiae. Using RNA-cleaving DNAzymes, we could specifically demonstrate that a significant amount of S. cerevisiae ribosomes are not methylated at 2'-O-ribose of A100 residue in the 18S rRNA. Furthermore, using LC-UV-MS/MS of a respective 18S rRNA fragment, we could not only corroborate the partial methylation at A100, but could also quantify the methylated versus non-methylated A100 residue. Here, we exhibit that only 68% of A100 in the 18S rRNA of S.cerevisiae are methylated at 2'-O ribose sugar. Polysomes also contain a similar heterogeneity for methylated Am100, which shows that 40S ribosome subunits with and without Am100 participate in translation. Introduction of a multicopy plasmid containing the corresponding methylation guide snoRNA gene SNR51 led to an increased A100 methylation, suggesting the cellular snR51 level to limit the extent of this modification. Partial rRNA modification demonstrates a new level of ribosome heterogeneity in eukaryotic cells that might have substantial impact on regulation and fine-tuning of the translation process.

  20. Tolerance of Immolpbilized Baker's Yeast on Organic Solvents%固定化酵母在有机溶剂中的耐受性研究

    Institute of Scientific and Technical Information of China (English)

    蒋群; 姚善泾; 梅乐和

    2001-01-01

    通过测定面包酵母在不同有机溶剂中浸泡24h后的代谢活力保留值,考察了固定化面包酵母与游离面包酵母对有机溶剂的耐受性,以及预培养时间和温度对其耐受性的影响.结果表明,面包酵母经固定化后,对有机溶剂的耐受性明显好于游离面包酵母,而且固定化面包酵母的耐受性与有机溶剂的logP值有关,logP值越大其耐受性越好.同时,温度对固定化面包酵母耐受性的影响与温度对面包酵母生长的影响相似,30℃时固定化面包酵母的耐受性最强;处于出芽高峰期的面包酵母,对有机溶剂的耐受性有所降低.

  1. Breeding of Excellent Baker's Yeast Strain with Good Flocculation%絮凝性强的优良面包酵母菌株的选育

    Institute of Scientific and Technical Information of China (English)

    刘春秀; 何秀萍; 蒋思欣; 曲娜; 张博润

    2003-01-01

    通过初筛、单倍体分离、DES诱变、絮凝基因的克隆表达及杂交等育种技术成功构建了高生物量、耐高糖、强絮凝的优良面包酵母菌株(Saccharomyces cerevisiae) ZLTH-58(MATa/α,leu,FLO1).菌株ZLTH-58具有双亲的优良性状,遗传性状稳定.对其生物量、耐高糖能力、絮凝特性进行了检测,结果表明,菌株ZLTH-58的生物量是原始亲株BL56的1.21倍;耐高糖能力优于原始亲株BL61;絮凝性能明显优于原始亲株BL56和BL61.对其培养条件进行了优化,在优化的培养条件下,生物量可以达到83.06g/L,为初始培养条件下的1.35倍.

  2. 消泡剂在面包酵母生产中的应用%Application of Antifoam to Baker's Yeast Production

    Institute of Scientific and Technical Information of China (English)

    覃先武; 陈晖; 匡金宝; 肖冬光

    2006-01-01

    消泡剂在面包酵母生产中有着特殊作用.研究了4种不同类型消泡剂对面包酵母发酵产量和酵母活力的影响,发现烷基脂肪酸酯的消泡效果最好.在此基础上,分析比较了3种消泡剂流加方式的应用情况.结果表明,发酵罐底部雾化流加方式能使消泡剂分布均匀且用量少,适合面包酵母大规模生产.

  3. 高蛋白面包酵母酶解过程的研究%Study on the Enzymatic Process of High Protein Content of Baker's Yeast

    Institute of Scientific and Technical Information of China (English)

    邹嫚; 李啸; 武业旭; 李知洪

    2013-01-01

    对高蛋白面包酵母的酶解过程进行了研究.首先,采用外源酶对其进行酶解,以氨基氮和总氮含量为响应值,系统考察了酶种类、pH值、温度、添加量、添加时间和酶解时间等因素对酶解过程的影响.在此基础上进行正交设计试验,得到了酵母酶解的最适条件为:温度60℃、pH值7、添加量0.3%、添加时间0h、酶解时间20 h.以此条件制备的酵母浸出物的氨基氮含量可达到5.33 g·L-1,总氮含量为12.04 g·L-1,上清液体积为7.5 mL,湿质量为2.512 g(总体积为10 mL).

  4. High Density Cultivation of Rotifer Brachionus plicatilis by Baker's Yeast%用酵母高密度培养褶皱臂尾轮虫

    Institute of Scientific and Technical Information of China (English)

    王鸿鹄; 吴灶和; 瘳永岩

    2009-01-01

    用面包酵母室内高密度培养褶皱臂尾轮虫,结果发现,1.5 g/(106·d)的较高投饵量.适合于接种密度约为50个/ml的褶皱臂尾轮虫培养,而投饵量为1.0~1.2 g/(106·d)时.适合于200个/ml以上较高密度的褶皱臂尾轮虫培养.投饵量为1.5 g/(106·d)时.不适于500个/ml以上接种密度的褶皱臂尾轮虫培养.若褶皱臂尾轮虫密度继续高至1000个/ml以上,投喂量则需进一步降低至1 0 g/(106·d)以下.褶皱臂尾轮虫接种密度低至30个/ml以下时,除酵母外,适当添加一定量(1/3以上体积)的单胞藻.可提高褶皱臂尾轮虫的增殖速度,降低褶皱臂尾轮虫培育的风险.

  5. Ribosomal DNA sequence heterogeneity reflects intraspecies phylogenies and predicts genome structure in two contrasting yeast species.

    Science.gov (United States)

    West, Claire; James, Stephen A; Davey, Robert P; Dicks, Jo; Roberts, Ian N

    2014-07-01

    The ribosomal RNA encapsulates a wealth of evolutionary information, including genetic variation that can be used to discriminate between organisms at a wide range of taxonomic levels. For example, the prokaryotic 16S rDNA sequence is very widely used both in phylogenetic studies and as a marker in metagenomic surveys and the internal transcribed spacer region, frequently used in plant phylogenetics, is now recognized as a fungal DNA barcode. However, this widespread use does not escape criticism, principally due to issues such as difficulties in classification of paralogous versus orthologous rDNA units and intragenomic variation, both of which may be significant barriers to accurate phylogenetic inference. We recently analyzed data sets from the Saccharomyces Genome Resequencing Project, characterizing rDNA sequence variation within multiple strains of the baker's yeast Saccharomyces cerevisiae and its nearest wild relative Saccharomyces paradoxus in unprecedented detail. Notably, both species possess single locus rDNA systems. Here, we use these new variation datasets to assess whether a more detailed characterization of the rDNA locus can alleviate the second of these phylogenetic issues, sequence heterogeneity, while controlling for the first. We demonstrate that a strong phylogenetic signal exists within both datasets and illustrate how they can be used, with existing methodology, to estimate intraspecies phylogenies of yeast strains consistent with those derived from whole-genome approaches. We also describe the use of partial Single Nucleotide Polymorphisms, a type of sequence variation found only in repetitive genomic regions, in identifying key evolutionary features such as genome hybridization events and show their consistency with whole-genome Structure analyses. We conclude that our approach can transform rDNA sequence heterogeneity from a problem to a useful source of evolutionary information, enabling the estimation of highly accurate phylogenies of

  6. 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...

  7. ATHYRIUM PALMENSE (CHRIST) LELLINGER Y ATHYRIUM SKINNERI (BAKER) DIELS (ATHYRIACEAE-PTERIDOPHYTA), NUEVA PROPUESTA PARA SU DELIMITACIÓN

    OpenAIRE

    Janet Vivero-Barón; María de la Luz Arreguín-Sánchez; David Leonor Quiroz-García; Rafael Fernández-Nava

    2010-01-01

    Se estudiaron las especies Athyrium palmense (Christ) Lellinger y Athyrium skinnneri (Baker) Diels, porque se consideró que su delimitación taxonómica no es clara. Se realizaron estudios de morfología externa, anatomía de la fronde y del rizoma, y morfología de las esporas de 60 ejemplares depositados en herbarios de México. Se encontró que no existen caracteres para separar a las dos especies y se consideró que se trata de una sola especie muy variable a la que corresponde designar con el no...

  8. Non-Linear N-Parameter Spacetime Perturbations: Gauge Transformations through the Baker-Campbell-Hausdorff Formula

    CERN Document Server

    Sopuerta, C F; Gualtieri, L; Sopuerta, Carlos F.; Bruni, Marco; Gualtieri, Leonardo

    2003-01-01

    We present a new way of deriving gauge transformations in non--linear relativistic perturbation theory. The main ingredient in this formulation is the use of the Baker-Campbell-Hausdorff formula. The associated formal machinery allows us to generalize one-parameter perturbation theory to an arbitrary number of parameters, and to prove the main results concerning the consistency of the scheme to any order in the perturbations. Gauge transformations at any required order can then be directly derived from a generating exponential formula via a simple Taylor expansion. We outline the relation between our novel formulation and previous results.

  9. Shuffling Yeast Gene Expression Data

    CERN Document Server

    Bilke, S

    2000-01-01

    A new method to sort gene expression patterns into functional groups is presented. The method is based on a sorting algorithm using a non-local similarity score, which takes all other patterns in the dataset into account. The method is therefore very robust with respect to noise. Using the expression data for yeast, we extract information about functional groups. Without prior knowledge of parameters the cell cycle regulated genes in yeast can be identified. Furthermore a second, independent cell clock is identified. The capability of the algorithm to extract information about signal flow in the regulatory network underlying the expression patterns is demonstrated.

  10. 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.

  11. 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... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.355 Phaffia yeast. (a) Identity. (1) The color additive phaffia yeast consists of the killed, dried cells of a nonpathogenic and nontoxicogenic strain of...

  12. Comparative Evaluation of the BD Phoenix Yeast ID Panel and Remel RapID Yeast Plus System for Yeast Identification

    OpenAIRE

    Michelle L. Grant; Shobha Parajuli; Raquel Deleon-Gonsalves; Raghava Potula; Truant, Allan L.

    2016-01-01

    Becton Dickinson Phoenix Yeast ID Panel was compared to the Remel RapID Yeast Plus System using 150 recent clinical yeast isolates and the API 20C AUX system to resolve discrepant results. The concordance rate between the Yeast ID Panel and the RapID Yeast Plus System (without arbitration) was 93.3% with 97.3% (146/150) and 95.3% (143/150) of the isolates correctly identified by the Becton Dickinson Phoenix and the Remel RapID, respectively, with arbitration.

  13. Vpliv relativne zračne vlažnosti in anoksičnih razmer na vezavo baker-etanolaminskih pripravkov v smrekovino

    OpenAIRE

    Biškup, Jure

    2014-01-01

    Med najpomembnejša zaščitna sredstva za impregnacijo lesa v 3. in 4. razredu izpostavitve spadajo baker-etanolaminski pripravki. Fiksacija teh pripravkov je v primerjavi s klasičnimi hitrejša in je končana v 2 do 24 urah po impregnaciji. Po določenem času se vezava teh pripravkov zopet poslabša. Ugotavljali smo kako različni postopki kondicioniranja vplivajo na vezavo baker-etanolaminskih pripravkov v les. Smrekove vzorce smo impregnirali s 3 koncentracijami zaščitnega pripravka Silvanolin (C...

  14. 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

  15. 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

  16. 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.

  17. The 'electric stroke' and the 'electric spark': anatomists and eroticism at George Baker's electric eel exhibition in 1776 and 1777.

    Science.gov (United States)

    Plumb, Christopher

    2010-09-01

    In 1776 and 1777 five living electric eels exhibited in London became a sensational spectacle that appealed to anatomists, electricians and connoisseurs of erotica. George Baker's exhibition made visible the 'electric spark' of the electrical eel and a series of experiments were both witnessed by and participated in by members of the Royal Society and the metropolitan elite. Some participants even grasped the eels firmly in their hands and felt the 'electric stroke' of the eel in addition to observing the spark. In their observation of the electric eel some of these spectators transposed the vivid electric spark from the sphere of electricians and anatomists into that of satirical and erotic literature. Here the erotic electric eel proliferated in the literature and the eel took on quite different connotations that nonetheless were reliant on readers knowledge and experience of the exhibition, experiments and the preoccupations of anatomists. George Baker's electric eel exhibition of 1776 and 1777 is then instructive in exploring the production and circulation of knowledge in Georgian Britain. The story of the electric eel in Georgian culture charts the creation of the electric spark and stroke as objects of observation and encounter, their exhibitionary context, and finally their divergent meanings as the electric eel became erotically charged for a metropolitan masculine elite.

  18. 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.

  19. Whey - raw material for the production of baker starter-cultures

    Directory of Open Access Journals (Sweden)

    Jasna Mrvčić

    2008-05-01

    Full Text Available The possibility of production Lactic acid bacteria (LAB, which are suitable for breadmaking on whey was researched and compared to the results achieved in modified MRS medium. The growth and fermentation activities of Leuconostoc meseteroides L-3, Lactobacillus brevis L-62 and Lactobacillus plantarum L-73 were examined by monitoring lactic and acetic acid production in fermentation broth and in sourdough. Presented results show that deproteinized whey is suitable for LAB production. The best biomass yield (1,7 g/L and lactic acid production (9,15 mg/mL was achieved with L. plantarum L-73. Better flavour, elasticity and shelf life of bread made with whey-based starters compared to the classical yeast-monoculture based bread were determined by sensory analysis (DLG method.

  20. Agave x güemensis Guillot & Meer (Agave polyacantha Haw. x Agave warelliana Baker), un nuevo híbrido dentro del grupo Polycephalae Gentry

    OpenAIRE

    Guillot Ortiz, Daniel; Van der Meer, Piet

    2005-01-01

    Se describe un nuevo híbrido dentro del género Agave L., a partir de ejemplares cultivados en el Jardín Botánico de Valencia, Agave x güemensis Guillot & Meer (Agave polyacantha Haw. x Agave warelliana Baker).

  1. A new Oligonychus and description of the female allotype of Oligonychus psidium Estebanes & Baker (Acari, Tetranychidae from Qualea grandiflora Mart. (Vochysiaceae in northwestern São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Reinaldo J.F. Feres

    1995-09-01

    Full Text Available Oligonychus longipenis, sp.n. and the female allotype of O. psidium Estebanes & Baker, 1968 from Qualea grandiflora Mart. (Vochysiaceae is described. The male of O. psidium is redescribed in Northwestern São Paulo (Brazil. This is the first record for 0. psidium in Brazil.

  2. 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...

  3. 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.

  4. Petrogenesis of Mt. Baker basalts (Cascade arc): Constraints from thermobarometry, phase equilibria, trace elements and isotopes

    Science.gov (United States)

    Mullen, E. K.; McCallum, I. S.

    2010-12-01

    Primitive arc basalts provide information on sub-arc mantle compositions and processes. The relative abundance of basalts in the Cascade arc decreases northward, and basalts are rare in the most northerly segment of the arc (Garibaldi belt) where the Mt. Baker volcanic field (MBVF) is located. Following reconstruction of the compositions of the primary basalts at MBVF (olivine addition ± plag subtraction), we have applied phase equilibria and forward-modeled trace element abundances and isotope ratios to obtain petrogenetic constraints. The most primitive lavas are the Sulphur Cr, Lk Shannon, and Park Butte basalts and the Hogback, Tarn Plateau, and Cathedral Crag basaltic andesites, ranging from 716 to 10 ka. Most erupted peripheral to the major centers. Spinel/olivine and Fe-Ti oxide oxybarometry indicate redox states of ~QFM + 1 corresponding to Fe3+/ΣFe = 0.20. Mg# ranges from 51 to 71. The lavas are medium-K and similar to calc-alkaline basalts and high-Mg basaltic andesites from the High Cascades. MBVF basalts have higher MgO and lower CaO and Al2O3 than typical CAB and HAOT, grading to alkalic compositions with TiO2 and Na2O of up to 1.65 and 5.4 wt%, respectively (Sulphur Cr). Phenocryst contents are 5 to 33% (plag + olivine ± cpx) and the lavas are holo- or hypocrystalline with glass contents of up to 15%. The whole rocks are close to equilibrium with olivine cores (range Fo 87-68). Plagioclase cores range from An 88-68. Reconstructed primary basalt compositions give liquidus T and P values (from olivine-liquid equilibria and silica activities) ranging from 1280°C and 1 GPa (Tarn Plateau) to 1350°C and 1.4 GPa (Sulphur Cr), corresponding to the upper mantle above the core of the mantle wedge. These estimates take into account the 1 to 3 wt% initial H2O contents of the basalts calculated using plagioclase cores. Phase equilibria of the primary basalts indicate a similar pressure range of 1-2 GPa and indicate a residual mantle assemblage of harzburgite

  5. Functional genomics of drug-induced ion homeostasis identifies a novel regulatory crosstalk of iron and zinc regulons in yeast.

    Science.gov (United States)

    Landstetter, Nathalie; Glaser, Walter; Gregori, Christa; Seipelt, Joachim; Kuchler, Karl

    2010-12-01

    Pyrrolidine dithiocarbamate (PDTC), a known inhibitor of NFκB activation, has antioxidative as well as antiviral activities. PDTC is effective against several virus families, indicating that its antiviral mechanism targets host rather than viral functions. To investigate its mode of action, we used baker's yeast as a simple eukaryotic model system and two types of genome-wide analysis. First, expression profiling using whole-genome DNA microarrays identifies more than 200 genes differentially regulated upon PDTC exposure. Interestingly, the Aft1-dependent iron regulon is a main target of PDTC, indicating a lack of iron availability. Moreover, the PDTC-caused zinc influx triggers a strong regulatory effect on zinc transporters due to the cytoplasmic zinc excess. Second, phenotypic screening the EUROSCARF collection for PDTC hypersensitivity identifies numerous mutants implicated in vacuolar maintenance, acidification as well as in transport, mitochondrial organization, and translation. Notably, the screening data indicate significant overlaps of PDTC-sensitive genes and those mediating zinc tolerance. Hence, we show that PDTC induces cytoplasmic zinc excess, eliciting vacuolar detoxification, which in turn, disturbs iron homeostasis and activates the iron-dependent regulator Aft1. Our work reveals a complex crosstalk in yeast ion homeostasis and the underlying regulatory networks.

  6. 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.

  7. Study on Total DNA Extraction of Alsophila costularis Baker and Its ISSR-PCR Analysis%中华桫椤DNA提取及ISSR分析

    Institute of Scientific and Technical Information of China (English)

    应站明; 黎桂芳; 王海舟

    2009-01-01

    [目的]研究中华桫椤总DNA的提取方法.[方法]采用SDS法和改良CTAB法提取中华桫椤总DNA,通过电泳检测方法进行比较.[结果]用改良CTAB法得到的DNA浓度和纯度都较高,基本上无蛋白质、多糖等杂质.用改良CTAB法得到的总DNA进行ISSR-PCR扩增,谱带清晰,获得较好的效果.[结论]为提取高质量的DNA样品奠定了基础,并为探讨中华桫椤自然居群的遗传多样性和种群遗传结构及进一步保护和利用中华桫椤提供了分子遗传学依据.%[Objective] The research aimed to study the total DNA extraction methods of A. costularis Baker.[Method] To investigate the optimum DNA extraction method, SDS and modified CTAB methods for isolating genomic DNA from A. costularis Baker leaf were studied. The isolated DNA was examined by ultraviolet absorption test and agarose gelelectrophoresis. [Result] The results showed that the modified CTAB method was suitable for DNA isolation from A. costularis Baker plants. The quality of DNA could meet ISSR requirement even extracted once by the modified CTAB method. [Conclusion] The study can provide the basis for extracting high quality DNA sample, and can offer the molecular genetics reference for exploring the genetic diversity and the population genetic structure of A. costularis Baker and deeply protecting and utilizing A. costularis Baker.

  8. 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.

  9. [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.

  10. 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.

  11. Allergy in bakers' apprentices and factors associated to non-participation in a cohort study of allergic sensitization

    DEFF Research Database (Denmark)

    Skjold, Tina; Nielsen, Sven C; Adolf, Katja;

    2006-01-01

    Objective  To describe the prevalence of atopy and respiratory symptoms among baker apprentices at the start of the education and factors associated with non-participation in the study. Methods  A total of 346 students, 22.1(0.6) years of age, mean (SD), from the food production programme...... of technical colleges in Denmark were invited to participate in a 3 year study. Of the students, 187 agreed to participate and filled in a physician-administered questionnaire. The presence of atopy was determined by skin prick test (SPT) and serum allergen specific IgE (SpIgE). Bronchial hyper responsiveness...

  12. 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...

  13. Validation of a predictive model for the growth of chalk yeasts on bread.

    Science.gov (United States)

    Burgain, Anaïs; Bensoussan, Maurice; Dantigny, Philippe

    2015-07-02

    The present study focused on the effects of temperature, T, and water activity, aw, on the growth of Hyphopichia burtonii, Pichia anomala, and Saccharomycopsis fibuligera on Sabouraud Agar Medium. Cardinal values were estimated by means of cardinal models with inflection. All the yeasts were xerophilic, and they exhibited growth at 0.85 aw. The combined effects of T, aw, and pH on the growth of these species were described by the gamma-concept and validated on bread in the range of 15-25 °C, 0.91-0.97 aw, and pH 4.6-6.8. The optimum growth rates on bread were 2.88, 0.259, and 1.06 mm/day for H. burtonii, P. anomala, and S. fibuligera, respectively. The optimal growth rate of S. fibuligera on bread was about 2 fold that obtained on Sabouraud. Due to reproduction by budding, P. anomala exhibited low growth on Sabouraud and bread. However, this species is of major concern in the baker's industry because of the production of ethyl acetate in bread.

  14. Yeast nitrogen catabolite repression is sustained by signals distinct from glutamine and glutamate reservoirs.

    Science.gov (United States)

    Fayyad-Kazan, Mohammad; Feller, A; Bodo, E; Boeckstaens, M; Marini, A M; Dubois, E; Georis, I

    2016-01-01

    Nitrogen catabolite repression (NCR) is a wide transcriptional regulation program enabling baker's yeast to downregulate genes involved in the utilization of poor nitrogen sources when preferred ones are available. Nowadays, glutamine and glutamate, the major nitrogen donors for biosyntheses, are assumed to be key metabolic signals regulating NCR. NCR is controlled by the conserved TORC1 complex, which integrates nitrogen signals among others to regulate cell growth. However, accumulating evidence indicate that the TORC1-mediated control of NCR is only partial, arguing for the existence of supplementary regulatory processes to be discovered. In this work, we developed a genetic screen to search for new players involved in NCR signaling. Our data reveal that the NADP-glutamate dehydrogenase activity of Gdh1 negatively regulates NCR-sensitive gene transcription. By determining the total, cytoplasmic and vacuolar pools of amino acids, we show that there is no positive correlation between glutamine/glutamate reservoirs and the extent of NCR. While our data indicate that glutamine could serve as initial trigger of NCR, they show that it is not a sufficient signal to sustain repression and point to the existence of yet unknown signals. Providing additional evidence uncoupling TORC1 activity and NCR, our work revisits the dogmas underlying NCR regulation.

  15. Microorganisms of the San Francisco sour dough bread process. I. Yeasts responsible for the leavening action.

    Science.gov (United States)

    Sugihara, T F; Kline, L; Miller, M W

    1971-03-01

    Two hundred isolates from San Francisco sour dough French bread fermentations (40 from each of five different bakeries) were screened by fermentation tests and for their ability to grow in the presence of cycloheximide (Actidione). All of the isolates from four of the bakeries and 70% of those from the fifth were unable to utilize maltose but grew well on other sugars, even in the presence of cycloheximide. The remaining few isolates from the fifth bakery utilized maltose but not galactose and were inhibited by cycloheximide. No bakers' yeast types were found. Sixteen of the maltose-negative and five of the galactose-negative isolates were subjected to more rigorous taxonomic procedures. All of the maltose-negative isolates were identified as asporogenous strains of Saccharomyces exiguus (Torulopsis holmii) and the galactose-negative ones, as S. inusitatus. The predominance of S. exiguus, its vigor in the particular acidic environment of the sour dough, and the correlation of its numbers with the leavening function constitute strong evidence on the role of this organism in the sour dough system.

  16. Assessing the complex architecture of polygenic traits in diverged yeast populations.

    Science.gov (United States)

    Cubillos, Francisco A; Billi, Eleonora; Zörgö, Enikö; Parts, Leopold; Fargier, Patrick; Omholt, Stig; Blomberg, Anders; Warringer, Jonas; Louis, Edward J; Liti, Gianni

    2011-04-01

    Phenotypic variation arising from populations adapting to different niches has a complex underlying genetic architecture. A major challenge in modern biology is to identify the causative variants driving phenotypic variation. Recently, the baker's yeast, Saccharomyces cerevisiae has emerged as a powerful model for dissecting complex traits. However, past studies using a laboratory strain were unable to reveal the complete architecture of polygenic traits. Here, we present a linkage study using 576 recombinant strains obtained from crosses of isolates representative of the major lineages. The meiotic recombinational landscape appears largely conserved between populations; however, strain-specific hotspots were also detected. Quantitative measurements of growth in 23 distinct ecologically relevant environments show that our recombinant population recapitulates most of the standing phenotypic variation described in the species. Linkage analysis detected an average of 6.3 distinct QTLs for each condition tested in all crosses, explaining on average 39% of the phenotypic variation. The QTLs detected are not constrained to a small number of loci, and the majority are specific to a single cross-combination and to a specific environment. Moreover, crosses between strains of similar phenotypes generate greater variation in the offspring, suggesting the presence of many antagonistic alleles and epistatic interactions. We found that subtelomeric regions play a key role in defining individual quantitative variation, emphasizing the importance of the adaptive nature of these regions in natural populations. This set of recombinant strains is a powerful tool for investigating the complex architecture of polygenic traits.

  17. Oscillatory, stochastic and chaotic growth rate fluctuations in permittistatically controlled yeast cultures.

    Science.gov (United States)

    Davey, H M; Davey, C L; Woodward, A M; Edmonds, A N; Lee, A W; Kell, D B

    1996-01-01

    We describe a continuous culture system related to the turbidostat, but using a feedback system based on biomass estimation from the dielectric permittivity of the cell suspension rather than its optical density. It is shown that this system provides an excellent method of maintaining a constant biomass level within a fermentor. The computer-controlled system was able to effect the essentially continuous registration of growth rate by monitoring the rate of medium addition via the time-dependent activity of the pump. At some biomass setpoints for aerobically grown cultures of baker's yeast substantial time-dependent fluctuations in the growth rate of the culture were thereby observed. At some biomass setpoints, however, or under anaerobic conditions, or when using a non-Crabtree yeast, the growth rate was constant, indicating that the fluctuations were inherent to the biological system and not simply a property of the fermentor and control system. A variety of time series analyses (Fourier transformations, Hurst and Lyapunov exponents, the determination of embedding dimension, and non-linear time series predictions based on the methodology of Sugihara and May) were used to demonstrate, for the first time, that as well as stochastic and periodic components these fluctuations exhibited deterministic chaos. 'Trivial predictors' were unable to give accurate predictions of the growth rate in these cultures. The growth rate fluctuations were studied further by means of offline measurements of changes in percentage viability, bud count, and in the external ethanol and glucose concentrations; these data and other evidence suggested that the growth rate fluctuations were closely linked to the primary respiro-fermentative metabolism of this organism. The identification of chaotic growth rates in cell cultures suggests that there may be novel methods for controlling the growth of such cultures.

  18. The oxidation of yeast alcohol dehydrogenase-1 by hydrogen peroxide in vitro.

    Science.gov (United States)

    Men, Lijie; Wang, Yinsheng

    2007-01-01

    Yeast alcohol dehydrogenase (YADH) plays an important role in the conversion of alcohols to aldehydes or ketones. YADH-1 is a zinc-containing protein, and it accounts for the major part of ADH activity in growing baker's yeast. To gain insight into how oxidative modification of the enzyme affects its function, we exposed YADH-1 to hydrogen peroxide in vitro and assessed the oxidized protein by LC-MS/MS analysis of proteolytic cleavage products of the protein and by measurements of enzymatic activity, zinc release, and thiol/thiolate loss. The results illustrated that Cys43 and Cys153, which reside at the active site of the protein, could be selectively oxidized to cysteine sulfinic acid (Cys-SO2H) and cysteine sulfonic acid (Cys-SO3H). In addition, H2O2 induced the formation of three disulfide bonds: Cys43-Cys153 in the catalytic domain, Cys103-Cys111 in the noncatalytic zinc center, and Cys276-Cys277. Therefore, our results support the notion that the oxidation of cysteine residues in the zinc-binding domain of proteins can go beyond the formation of disulfide bond(s); the formation of Cys-SO2H and Cys-SO3H is also possible. Furthermore, most methionines could be oxidized to methionine sulfoxides. Quantitative measurement results revealed that, among all the cysteine residues, Cys43 was the most susceptible to H2O2 oxidation, and the major oxidation products of this cysteine were Cys-SO2H and Cys-SO3H. The oxidation of Cys43 might be responsible for the inactivation of the enzyme upon H2O2 treatment.

  19. Triosephosphate isomerase: energetics of the reaction catalyzed by the yeast enzyme expressed in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Nickbarg, E.B.; Knowles, J.R.

    1988-08-09

    Triosephosphate isomerase from bakers' yeast, expressed in Escherichia coli strain DF502(p12), has been purified to homogeneity. The kinetics of the reaction in each direction have been determined at pH 7.5 and 30 degrees C. Deuterium substitution at the C-2 position of substrate (R)-glyceraldehyde phosphate and at the 1-pro-R position of substrate dihydroxyacetone phosphate results in kinetic isotope effects on kcat of 1.6 and 3.4, respectively. The extent of transfer of tritium from (1(R)-TH)dihydroxyacetone phosphate to product (R)-glyceraldehyde phosphate during the catalyzed reaction is only 3% after 66% conversion to product, indicating that the enzymic base that mediates proton transfer is in rapid exchange with solvent protons. When the isomerase-catalyzed reaction is run in tritiated water in each direction, radioactivity is incorporated both into the remaining substrate and into the product. In the exchange-conversion experiment with dihydroxyacetone phosphate as substrate, the specific radioactivity of remaining dihydroxyacetone phosphate rises as a function of the extent of reaction with a slope of about 0.3, while the specific radioactivity of the products is 54% that of the solvent. In the reverse direction with (R)-glyceraldehyde phosphate as substrate, the specific radioactivity of the product formed is only 11% that of the solvent, while the radioactivity incorporated into the remaining substrate (R)-glyceraldehyde phosphate also rises as a function of the extent of reaction with a slope of 0.3. These results have been analyzed according to the protocol described earlier to yield the free energy profile of the reaction catalyzed by the yeast isomerase.

  20. X-ray structures of recombinant yeast cytochrome c peroxidase and three heme-cleft mutants prepared by site-directed mutagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Mauro, J.M.; Edwards, S.L.; Oatley, S.J.; Fishel, L.A.; Ashford, V.A.; Xuong, Nguyenhuu; Kraut, J. (Univ. of California at San Diego, La Jolla (USA))

    1990-08-07

    The 2.2-{angstrom} x-ray structure for CCP(MI), a plasmid-encoded form of Saccharomyces cerevisiae cytochrome c peroxidase (CCP) expressed in Escherichia coli has been solved, together with the structures of three specifically designed single-site heme-cleft mutants. The structure of CCP(MI) was solved by using molecular replacement methods, since its crystals grow differently from the crystals of CCP isolated from bakers' yeast used previously for structural solution. Small distal-side differences between CCP(MI) and bakers' yeast CCP are observed, presumably due to a strain-specific Thr-53 {yields} Ile substitution in CCP(MI). The observation of a vacant sixth coordination site in this structure differs from the results of solution resonance Raman studies, which predict hexacoordinated high-spin iron. The coordination behavior of this W51F mutant is apparently altered in the presence of a precipitating agent, 30% 2-methyl-2,4-pentanediol. A proximal Trp-191 {yields} Phe mutant that has substantially diminished enzyme activity and altered magnetic properties accommodates the substitution by allowing the side chain of Phe-191, together with the segment of backbone to which it is attached, to move toward the heme. This relatively large local perturbation is accompanied by numerous small adjustments resulting in a slight overall compression of the enzyme's proximal domain; however, the iron coordination sphere is essentially unchanged. This structures rules out a major alteration in protein conformation as a reason for the dramatically decreased activity of the W191F mutant. From the alteration of local structure that occurs in this mutant, coupled with the results of preliminary functional studies, the authors infer that Asp-235 exerts influence on the heme iron so as to keep its sixth coordination site vacant, and hence reactive with peroxide substrate, over a wide pH range.

  1. 28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

    CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

  2. Biofuels. Altered sterol composition renders yeast thermotolerant

    DEFF Research Database (Denmark)

    Caspeta, Luis; Chen, Yun; Ghiaci, Payam;

    2014-01-01

    Ethanol production for use as a biofuel is mainly achieved through simultaneous saccharification and fermentation by yeast. Operating at ≥40°C would be beneficial in terms of increasing efficiency of the process and reducing costs, but yeast does not grow efficiently at those temperatures. We use...

  3. 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.

  4. 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

  5. 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...

  6. Biological cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae on leaflets of three rubber tree clones Ciclo de vida de Tenuipalpus heveae Baker (Acari, Tenuipalpidae em folíolos de três clones de seringueira

    Directory of Open Access Journals (Sweden)

    Reinaldo José Fazzio Feres

    2010-06-01

    Full Text Available Life cycle of Tenuipalpus heveae Baker (Acari, Tenuipalpidae on leaflets from three rubber tree clones. The biological cycle of Tenuipalpus heveae Baker, 1945 (Tenuipalpidae, a potential rubber tree pest mite, was studied by the observation of individuals reared on leaflets of the clones GT 1, PB 235 and RRIM 600, in controlled environmental conditions. Three daily observations were done of 60 eggs on leaflets from each clone in order to verify the development of immature stages and the female oviposition. The fertility life table was constructed based in the collected data. Mites reared on PB 235 had faster rate of development, requiring less time in days, to double its population in number (TD, and had the highest values for egg production, female longevity, net reproductive rate (Ro, intrinsic rate of natural increase (r m and finite rate of increase (λ. Lower reproductive values and the longest time necessary to reach adult stage were recorded for the mites on GT 1. In all studied clones, the deutonymphal phase had the highest viability, while the larval phase had the lowest, highlighted by the survivorship curve that indicated high mortality during this life stage. The clone PB 235 allowed the most suitable conditions for the development of T. heveae, followed by RRIM 600, while GT 1 was the less suitable substratum to rear this mite species.O ciclo de vida de Tenuipalpus heveae Baker, 1945 (Tenuipalpidae, um potencial ácaro-praga da seringueira, foi estudado a partir de indivíduos criados sobre folíolos destacados dos clones GT 1, PB 235 e RRIM 600, em condições controladas. Três observações diárias foram realizadas, acompanhando-se o desenvolvimento de 60 ovos e de sua prole em folíolos de cada um dos clones, para verificação da oviposição das fêmeas e dos estágios de desenvolvimento. A partir dos dados obtidos, foi elaborada uma tabela de vida de fertilidade. Os ácaros criados sobre folíolos de PB 235 apresentaram r

  7. 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...

  8. Ceramide Accumulation in Yeast Yarrowia lipolitica

    Institute of Scientific and Technical Information of China (English)

    周全; 陈国强

    2005-01-01

    Ceramides are a class of lipid molecules widely distributed in eukaryotic cells in small amount. To investigate the possibility of ceramide production by yeast, a yeast strain Yarrowia lipolitica was grown under different conditions including changing carbon/nitrogen ratio, and serine concentration, dissolved oxygen and presence of ethanol. It was found that increased dissolved oxygen supply increased the ceramide content in the yeast 2.5 fold of its normal control level. Ethanol treatment could also enhance ceramide accumulation by 3.3 fold compared with the control although the cell growth was negatively affected. Cellular redox potential was shown to affect ceramide accumulation by the yeast. This was possibly related to the cellular reactive oxygen species presented in the yeast.

  9. Estudios sobre semilla de Hypochaeris variegata L. (Baker: aceite seminal y harina residual de extracción

    Directory of Open Access Journals (Sweden)

    Nolasco, S. M.

    2000-08-01

    Full Text Available Seeds from Hypochaeris variegata L. (Baker harvested at Olavarría (Buenos Aires, Argentine were defatted with hexane and the raw oil obtained with a yield of 24,7% dry basis. The crude oil was examined in their physicochemical characteristics had refractive index of 1,4637 (at 25ºC, iodine value of 125,2, saponification index of 188,4, unsaponifiable matter of 8,5 % and free fatty acid content of 9,7 (mg KOH/g. Gas chromatographic analysis of the oil revealed high levels of linoleic acid (66,2%, appreciable amount of linolenic and erucic acids. The residual seed meal contained 35,49% of crude protein and 35,1% of crude fiber. Total and phytic acid phosphorous, calcium, ash, sugar and polisaccharides (non presence of starch contents are reported.Semillas de Hypochaeris variegata L. (Baker cosechadas en Olavarría (prov. de Buenos Aires, Argentina se extrajeron con hexano (soxhlet obteniéndose el aceite crudo con un rendimiento del 24,7 % (b.s. y la harina residual de extracción. El aceite crudo se examinó en sus características fisicoquímicas (Indice de refracción: 1.4637 (a 25ºC, Indice de iodo: 125,2, Indice de saponificación: 188,4, insaponificable: 8,5%, Indice de acidez: 9,7 (mgKOH/g y composición acídica. El análisis por cromatografía gaseosa de los ésteres metílicos revela un alto porcentaje de ácido linoleico (66,2%, cantidades apreciables de ácido linolénico y erúcico. La harina residual de extracción presentó un 35,49% b.s. de proteína cruda y 35,1% b.s. de fibra cruda. Se informan valores de fósforo total y de ácido fítico, cenizas, calcio e hidratos de carbono.

  10. Rock property measurements guide interpretation of electromagnetic, magnetic and gravity models at Mts. Adams, Baker, Rainier and St. Helens (Invited)

    Science.gov (United States)

    Finn, C.; Bedrosian, P. A.; Horton, R.; Polster, S.

    2010-12-01

    Mt. Adams north of the summit. Alteration at Mt. Baker is restricted to thinner (transform debris avalanches into lahars. The EM data identified water-saturated rocks from the surface to the detection limit (100 - 200 m) in discreet zones at Mt. Rainier and Mt Adams and over the entire summit region at Mt. Baker. At Mt. St. Helens, perched aquifers are identified in the 1980 avalanche deposits as well as in older, thick breccia or avalanche deposits. The modeled distribution of alteration and pore fluids helps identify likely sources for future alteration-related debris flows and clearly shows that debris flow hazard studies on altered volcanoes are greatly enhanced by magnetic, EM and gravity data.

  11. Modeling competition between yeast strains

    Science.gov (United States)

    de Gee, Maarten; van Mourik, Hilda; de Visser, Arjan; Molenaar, Jaap

    2016-04-01

    We investigate toxin interference competition between S. cerevisiae colonies grown on a solid medium. In vivo experiments show that the outcome of this competition depends strongly on nutrient availability and cell densities. Here we present a new model for S. cerevisiae colonies, calculating the local height and composition of the colonies. The model simulates yeast colonies that show a good fit to experimental data. Simulations of colonies that start out with a homogeneous mixture of toxin producing and toxin sensitive cells can display remarkable pattern formation, depending on the initial ratio of the strains. Simulations in which the toxin producing and toxin sensitive species start at nearby positions clearly show that toxin production is advantageous.

  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. 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... CONSUMPTION Flavoring Agents and Related Substances § 172.590 Yeast-malt sprout extract. Yeast-malt sprout... prescribed conditions: (a) The additive is produced by partial hydrolysis of yeast extract (derived...

  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. Biosynthesis of lead nanoparticles by the aquatic water fern, Salvinia minima Baker, when exposed to high lead concentration.

    Science.gov (United States)

    Castro-Longoria, E; Trejo-Guillén, K; Vilchis-Nestor, A R; Avalos-Borja, M; Andrade-Canto, S B; Leal-Alvarado, D A; Santamaría, J M

    2014-02-01

    Salvinia minima Baker is a small floating aquatic fern that is efficient for the removal and storage of heavy metals such as lead and cadmium. In this study, we report that lead removal by S. minima causes large accumulation of lead inside the cells in the form of nanoparticles (PbNPs). The accumulation pattern of lead was analyzed in both, submerged root-like modified fronds (here named "roots"), and in its aerial leaf-like fronds ("leaves"). Analysis by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) confirmed the biosynthesis of PbNPs by the plant. In both, roots and leaves, PbNPs were found to accumulate almost exclusively at the cell wall and closely associated to the cell membrane. Two types of PbNPs shapes were found in cells of both tissues, those associated to the cell wall were quasi-spherical with 17.2±4.2 nm of diameter, while those associated to the cell membrane/cytoplasm were elongated. Elongated particles were 53.7±29.6 nm in length and 11.1±2.4 nm wide. Infrared spectroscopy (IR) results indicate that cellulose, lignin and pectin are the major components that may be acting as the reducing agents for lead ions; these findings strongly suggest the potential use of this fern to further explore the bio-assisted synthesis of heavy metal nanostructures.

  16. “YONDER LIES YOUR HINTERLAND”: RHODES, BAKER AND THE TWISTED STRANDS OF THE SOUTH AFRICAN ARCHITECTURAL TRADITION

    Directory of Open Access Journals (Sweden)

    J.M. Claassen

    2012-03-01

    Full Text Available This article considers the various strands that make up the classical architectural tradition in South Africa. In the last quarter of the nineteenth century and the beginning of the twentieth, under British rule the tradition of the Palladian style for civic buildings and of Graeco-Roman building styles for institutions of higher learning reflected the imperial ideals of South Africa’s political overlords. This was the tradition in which Sir Herbert Baker had been trained and which he encountered when he reached South Africa late in the nineteenth century. South African architecture would have been less rich without the strong influence of Cecil John Rhodes’ admiration for indigenous Cape Dutch architecture on Baker’s architectural taste. This architecture was strongly rooted in another aspect of the classical tradition. During Dutch economic and imperial rule, the northern European style of classicistic or baroque gabling on perpendicular buildings had at the Cape been translated into the gables of sprawling low buildings. Illustrations show earlier examples of classical styles at the Cape, including examples of the second classical strain (via Holland and Germany in South African architecture, so much admired by Rhodes. The article continues with an examination of some of Baker’s best known buildings that show a blending of these two strands. It ends with some thoughts on the durability of the Classical tradition and neo-classical vestiges in post-colonial (and postapartheid South Africa.

  17. Closed form of the Baker-Campbell-Hausdorff formula for the generators of semisimple complex Lie algebras

    Science.gov (United States)

    Matone, Marco

    2016-11-01

    Recently it has been introduced an algorithm for the Baker-Campbell-Hausdorff (BCH) formula, which extends the Van-Brunt and Visser recent results, leading to new closed forms of BCH formula. More recently, it has been shown that there are 13 types of such commutator algebras. We show, by providing the explicit solutions, that these include the generators of the semisimple complex Lie algebras. More precisely, for any pair, X, Y of the Cartan-Weyl basis, we find W, linear combination of X, Y, such that exp (X) exp (Y)=exp (W). The derivation of such closed forms follows, in part, by using the above mentioned recent results. The complete derivation is provided by considering the structure of the root system. Furthermore, if X, Y, and Z are three generators of the Cartan-Weyl basis, we find, for a wide class of cases, W, a linear combination of X, Y and Z, such that exp (X) exp (Y) exp (Z)=exp (W). It turns out that the relevant commutator algebras are type 1c-i, type 4 and type 5. A key result concerns an iterative application of the algorithm leading to relevant extensions of the cases admitting closed forms of the BCH formula. Here we provide the main steps of such an iteration that will be developed in a forthcoming paper.

  18. Closed form of the Baker-Campbell-Hausdorff formula for the generators of semisimple complex Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Matone, Marco [Universita di Padova, Dipartimento di Fisica e Astronomia ' ' G. Galilei' ' , Padua (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padua (Italy)

    2016-11-15

    Recently it has been introduced an algorithm for the Baker-Campbell-Hausdorff (BCH) formula, which extends the Van-Brunt and Visser recent results, leading to new closed forms of BCH formula. More recently, it has been shown that there are 13 types of such commutator algebras. We show, by providing the explicit solutions, that these include the generators of the semisimple complex Lie algebras. More precisely, for any pair, X, Y of the Cartan-Weyl basis, we find W, linear combination of X, Y, such that exp(X) exp(Y) = exp(W). The derivation of such closed forms follows, in part, by using the above mentioned recent results. The complete derivation is provided by considering the structure of the root system. Furthermore, if X, Y, and Z are three generators of the Cartan-Weyl basis, we find, for a wide class of cases, W, a linear combination of X, Y and Z, such that exp(X) exp(Y) exp(Z) = exp(W). It turns out that the relevant commutator algebras are type 1c-i, type 4 and type 5. A key result concerns an iterative application of the algorithm leading to relevant extensions of the cases admitting closed forms of the BCH formula. Here we provide the main steps of such an iteration that will be developed in a forthcoming paper. (orig.)

  19. 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/.

  20. 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...

  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. 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

  3. Structure and function of yeast alcohol dehydrogenase

    OpenAIRE

    VLADIMIR LESKOVAC; SVETLANA TRIVIC

    2000-01-01

    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

  4. 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)

  5. 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.

  6. 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.

  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. 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.

  9. 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.

  10. 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

  11. 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.

  12. Variações na morfoanatomia foliar de Aechmea lindenii (E. Morren Baker var. lindenii (Bromeliaceae sob distintas condições ambientais Leaf morphoanatomy variation in Aechmea lindenii (E. Morren Baker var. lindenii (Bromeliaceae under distinct environmental conditions

    Directory of Open Access Journals (Sweden)

    Caroline Heinig Voltolini

    2011-03-01

    Full Text Available Aechmea lindenii (E. Morren Baker var. lindenii (Bromeliaceae-Bromelioideae ocorre em restingas e Floresta Pluvial de Encosta Atlântica em Santa Catarina e Nordeste do Rio Grande do Sul, BR. Pode ser encontrada total ou parcialmente exposta à irradiação solar e em distintas formas de vida - terrícola, rupícola e epifítica. O objetivo deste trabalho foi comparar morfoanatomicamente às características de folhas de A. lindenii var. lindenii em distintas condições ambientais. Foram coletadas, na Ilha de Santa Catarina (Florianópolis, SC, folhas de plantas terrícolas em restinga herbácea (alta irradiação solar, rupícolas de costões rochosos (alta irradiação solar, terrícolas e epifíticas de sub-bosques (baixa irradiação solar de restinga arbórea e rupícolas de sub-bosque (baixa irradiação solar de Floresta Pluvial de Encosta Atlântica. Foram mensurados comprimento, largura, área da lâmina e bainha foliar, densidade estomática, comprimento e largura das células-guarda, espessura total e das estruturas constituintes na lâmina foliar. As características anatômicas qualitativas são semelhantes nas distintas condições analisadas. A baixa irradiação solar determina maior expansão da área foliar, decorrente do alongamento da lâmina. Lâmina e bainha foliares têm maior largura sob alta irradiação. A densidade estomática foi maior em folhas de plantas sob alta irradiação solar. A espessura total da lâmina foliar foi menor em plantas terrícolas sob alta irradiação, porém não mostrou diferenças estatísticas significativas entre as outras condições.Aechmea lindenii (E. Morren Baker var. lindenii (Bromeliaceae-Bromelioideae occurs in restingas and hillside Atlantic rain forest in Santa Catarina and northeastern Rio Grande do Sul, Brazil. It is found totally or partially exposed to solar radiation and in different life forms - terricolous, rupicolous and epiphytes. The aim of this work was to compare

  13. Produção de frutanos em calos e plântulas clonadas in vitro de Viguiera discolor Baker (Asteraceae Fructan production in callus and in vitro cloned seedlings of Viguiera discolor Baker (Asteraceae

    Directory of Open Access Journals (Sweden)

    Nair Massumi Itaya

    2005-09-01

    Full Text Available Viguiera discolor Baker é uma espécie nativa do cerrado, cuja sobrevivência está ameaçada pela invasão de espécies exóticas. Considerando sua elevada produção e a vasta aplicação de frutanos, o presente trabalho foi conduzido visando à obtenção in vitro dessa espécie e à prospecção desses carboidratos nessas condições. Sementes foram germinadas in vitro, em meio MS modificado, e após cinco semanas de incubação, nós caulinares foram isolados e incubados no mesmo meio adicionado de 0,5 mg L-1 de ANA, regenerando plantas uniformes, raízesnão espessadas, raízes tuberosas e estruturas semelhantes a calo (calo tipo1, formadas na região caulinar basal. Análise desse material evidenciou a presença de frutanos do tipo inulina nas raízes tuberosas e nos calos tipo 1. Na presença de 2,4-D obteve-se a formação de calos friáveis (calo tipo 2, nos quais também foram detectados frutanos e suas enzimas de síntese sacarose: sacarose 1-frutosiltransferase (SST e frutano: frutano 1-frutosiltransferase (FFT. Embora em concentrações menores às observadas nas plantas cultivadas sob condições naturais, o material produzido in vitro apresentou frutanos do mesmo tipo e razão SST/FFT menor do que um. Em meio de cultura sem hormônios, foi verificada a regeneração de 50% de plantas a partir dos nós caulinares. A propagação de V. discolor in vitro pode viabilizar a multiplicação e a preservação da espécie, bem como a produção de frutanos nessas condições.Viguiera discolor Baker is a herbaceous species, native to cerrado and its survival has been threatened by the invasion of exotic species. Considering its high production and the wide application of fructans, the present work has aimed to establish in vitro culture of this species and to investigate the presence of fructans under these conditions. Seeds were germinated in vitro on modified MS medium and after plant growth, stem nodes were isolated and incubated on

  14. Optimization of feeding strategy for the ergosterol production by yeasts Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Mojmir Rychtera

    2010-08-01

    Full Text Available Objective of this study was to optimize ergosterol production by yeast strain Saccharomyces cerevisiae with the use of computer controlled feeding of cultivation medium. Baker´s yeasts strain of Saccharomyces cerevisiae originally modified and selected as mutant D7 was further applied in an industrial scale and also in this investigation. Composition of cultivation medium was optimized with the use of a modified Rosenbrock´s method with regard to following components: glucose, yeast extract, ammonium sulphate, potassium dihydrogen phosphate, magnesium sulphate and calcium chloride. Cultivation of yeast culture was performed in 7 L laboratory bioreactor with a working volume of 5 L equipped with a control unit and linked to a computer, with dissolved oxygen tension measurement, oxygen and carbon dioxide analyzers. BIOGENES prototype software was created from the commercial control system Genesis for Windows 3.0 (GFW, from Iconics and CLIPS 6.04 for the PC-Windows platform. From various factors affecting sterol biosynthesis a specific growth rate was chosen. Feed rate was controlled according to mathematical model. In this case it dealt with a design of optimal profile of specific growth rate with consequent calculation of carbon dioxide profile. Sterol concentration in the dry biomass increased from 1.0 % up to 3 %. Key words: Saccharomyces cerevisiae yeasts, ergosterol, fed-batch cultivation control, effect of the specific growth rate. Resumen: El objetivo de este estudio fue optimizar la producción de ergosterol por una cepa de levadura Saccharomyces cerevisiae, controlando la alimentación de medio de cultivo por computadora. La cepa de levadura panadera Saccharomyces cerevisiae originalmente modificada y seleccionada como mutante D7 fue posteriormente utilizada a escala industrial y también para esta investigación. La composición del medio de cultivo fue optimizada usando el método modificado de Rosenbrock respecto a los siguientes

  15. Use of Saccharomyces cerevisiae yeasts in the chemo selective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)-1,4-pentadien-3-one in biphasic system

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Cesar A.; Silva, Vanessa D.; Nascimento, Maria da G., E-mail: maria.nascimento@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis-SC (Brazil); Stambuk, Boris U. [Departamento de Bioquimica, Universidade Federal de Santa Catarina, Florianopolis-SC (Brazil)

    2013-07-15

    This work describes the chemoselective bioreduction of (1E,4E)-1,5-bis(4-methoxyphenyl)- 1,4-pentadien-3-one (1) mediated by baker's yeast (BY, Saccharomyces cerevisiae cells) in an aqueous/organic solvent biphasic system. The biotransformation of this compound was chemoselective and formed only the corresponding saturated ketone 1,5-bis(4-methoxyphenyl)- 3-pentanone (2). The influence of various factors which may alter the bioreduction of 1, such as the type and percentage of co-solvents, use of six different S. cerevisiae yeast samples (four commercial and two industrial), variations in the substrate and yeast concentrations, temperature, pH and volume of aqueous and organic phases, was investigated. The best reaction conditions were 66.7 g L{sup -1} of Fleischmann BY, 8.3 Multiplication-Sign 10{sup -3} mol L{sup -1} of substrate, pH 6.5 at 35 deg C in the presence of 2.5% (v/v) of N,N-dimethyl sulfoxide (DMSO) as an additive and a V{sub aq}/V{sub org} ratio of 70/30. Under these conditions, the product 2 was recovered in conversions of 82% in 5 h reaction. (author)

  16. 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.

  17. NetPhosYeast: prediction of protein phosphorylation sites in yeast

    DEFF Research Database (Denmark)

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

    2007-01-01

    sites compared to those in humans, suggesting the need for an yeast-specific phosphorylation site predictor. NetPhosYeast achieves a correlation coefficient close to 0.75 with a sensitivity of 0.84 and specificity of 0.90 and outperforms existing predictors in the identification of phosphorylation sites...

  18. 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.

  19. 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

  20. 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

  1. 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.).

  2. 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

  3. 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

  4. 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

  5. Phytochemical and bio-efficacy studies on methanolic flower extracts of Peltophorum pterocarpum (DC.) Baker ex Heyne.

    Institute of Scientific and Technical Information of China (English)

    Vinod Kumar Nathan; Johnson Marimuthu Antonisamy; Wesely Edward Gnanaraj

    2012-01-01

    Objective: The present study was aimed to investigate the preliminary phytochemical analysis and HPTLC profiling and the antibacterial activity of P. pterocarpum methanolic flower extracts against the bacteria isolated from human infections. Methods: The preliminary phytochemical screening was performed according to the Harborne method. HPTLC studies were carried out using Harborne and Wagner et al method. The methanolic flower extracts of P. pterocarpum were tested against Salmonella typhi (MTCC 733), Staphylococcus aureus (MTCC 96), Proteus mirabilis (MTCC 742), Bacillus subtilis (MTCC 441) and Escherichia coli (MTCC 443). The antimicrobial activity was tested through well diffusion method. Results: The phytochemical studies on methanolic flower extract of Peltophorum pterocarpum (DC.) Baker ex Heyne. revealed the presence of glycosides, flavonoids, phenolics, saponins, catechin and alkaloids. The HPTLC separation was achieved using ethyl acetate-methanol-ethanol-water (8.1: 1.1: 0.4: 0.8) as the mobile phase. The methanolic extract of P. pterocarpum showed four different Rf values 0.16, 0.31, 0.77 and 0.82 which indicated various glycosides present in the flower extract. The methanolic extract of P. pterocarpum showed the maximum zone of inhibition against Proteus mirabilis followed by Salmonella typhi. Conclusion: Bio-assay revealed the presence of specific and selective antimicrobial compounds in the fractions. Broad range activity of plant extracts as per observations in this study was due to presence of multiple antimicrobial compounds or synergic effects of these compounds. Therefore, standardization of active fractions and study for in vivo efficacy may result in development of better antimicrobial drugs.

  6. Preparing for Volcanic Hazards: An Examination of Lahar Knowledge, Risk Perception, and Preparedness around Mount Baker and Glacier Peak, WA

    Science.gov (United States)

    Corwin, K.; Brand, B. D.

    2015-12-01

    As the number of people living at risk from volcanic hazards in the U.S. Pacific Northwest continues to rise, so does the need for improved hazard science, mitigation, and response planning. The effectiveness of these efforts relies not only on scientists and policymakers, but on individuals and their risk perception and preparedness levels. This study examines the individual knowledge, perception, and preparedness of over 500 survey respondents living or working within the lahar zones of Mount Baker and Glacier Peak volcanoes. We (1) explore the common disconnect between accurate risk perception and adequate preparedness; (2) determine how participation in hazard response planning influences knowledge, risk perception, and preparedness; and (3) assess the effectiveness of current lahar hazard maps for public risk communication. Results indicate that a disconnect exists between perception and preparedness for the majority of respondents. While 82% of respondents accurately anticipate that future volcanic hazards will impact the Skagit Valley, this knowledge fails to motivate increased preparedness. A majority of respondents also feel "very responsible" for their own protection and provision of resources during a hazardous event (83%) and believe they have the knowledge and skills necessary to respond effectively to such an event (56%); however, many of these individuals still do not adequately prepare. When asked what barriers prevent them from preparing, respondents primarily cite a lack of knowledge about relevant local hazards. Results show that participation in response-related activities—a commonly recommended solution to this disconnect—minimally influences preparedness. Additionally, although local hazard maps successfully communicate the primary hazard—97% of respondents recognize the lahar hazard—many individuals incorrectly interpret other important facets of the maps. Those who participate in response-related activities fail to understand these

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Resistance of tomato genotypes with high level of acylsugars to Tetranychus evansi Baker & Pritchard Resistência de genótipos de tomateiro com alto teor de acilaçúcares a Tetranychus evansi Baker & Pritchard

    Directory of Open Access Journals (Sweden)

    Juliano Tadeu Vilela de Resende

    2008-02-01

    Full Text Available The Lycopersicon pennellii accession LA716 has been used as a source of arthropod pest resistance in tomato breeding programs due the high contents of acylsugars presents in its leaflets. We investigated the relationship between high foliar acylsugar contents and repellence to spider mite Tetranychus evansi in plants with contrasting acylsugar levels, selected from F2 and BC1F2 (= F2 of the first backcross towards L. esculentum generations derived from the interespecific cross L. esculentum 'TOM-584' ´ L. pennellii LA716. Mite resistance was assessed by a repellence test. Plants selected for high levels of acylsugars in leaflets had mite repellence levels similar to that of LA716. The high correlation confirmed the association between high acylsugar levels and mite repellence.O acesso de Lycopersicon pennellii LA716 tem sido utilizado em programas de melhoramento do tomateiro devido à sua resistência a artrópodos-pragas, mediada pela presença de acilaçúcares nos folíolos. Foi verificada a correlação entre o teor de acilaçúcares em folíolos de tomateiros e a repelência ao ácaro Tetranychus evansi Baker & Pritchard. Foram selecionadas plantas contrastantes quanto aos níveis de acilaçúcares nos folíolos de populações F2 e F2RC1 (= F2 do primeiro retrocruzamento para Lycopersicon esculentum do cruzamento interespecífico de L. esculentum TOM 584 (baixo teor de acilaçúcares e L. pennellii LA 716 (alto teor. Foi realizado um teste de repelência ao ácaro T. evansi, tomando por base a distância percorrida pelos ácaros nos folíolos. Os genótipos selecionados para alto teor de acilaçúcares, em média, foram responsáveis por reduções significativas nas distâncias percorridas pelos ácaros sobre a superfície do folíolo. A repelência ao ácaro T. evansi exercida pelas plantas selecionadas para alto teor de acilaçúcares deu-se de forma semelhante àquela conferida pelo genitor LA-716. As magnitudes das correla

  16. 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.

  17. 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.

  18. 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.

  19. Modeling diauxic glycolytic oscillations in yeast

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Sørensen, Preben Graae

    2010-01-01

    switching in a closed-system experiment by feeding the yeast suspension with a glucose pulse-notably the initial NADH spike and final NADH rise. Another object of this study is to gain insight into the secondary low-flux metabolic pathways by feeding starved yeast cells with various metabolites......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 characterized quantitatively by experimental quenching and bifurcation analysis. In this article, we use these methods to show that the dynamics of oscillations in a closed system is a simple transient version of the open-system dynamics. Thus, easy-setup closed-system experiments are also useful...

  20. 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.